PLB31619S0370-2693(15)01015-110.1016/j.physletb.2015.12.067CERN for the benefit of the ALICE CollaborationExperimentsFig. 1(a): Measured dE/dx in the TPC as function of momentum p expressed as a deviation from the expected energy loss of electrons, normalised by the energy-loss resolution (σTPC) after eID with TOF. The solid lines indicate the nσTPC selection criteria for the TPC and TOF eID strategy. (b): E/p distribution of electrons (−1<nσTPC<3) and hadrons (nσTPC<−3.5) in the transverse momentum interval 6<pT<8 GeV/c. The E/p distribution of hadrons was normalised to that of electrons in the lower E/p range (0.4–0.6), where hadrons dominate. The solid lines indicate the applied electron selection criteria. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)Fig. 2Invariant mass distributions of unlike-sign and like-sign electron pairs for the inclusive electron pT interval 0.5<pT<0.6 GeV/c. The difference between the distributions yields the photonic contribution.Fig. 3The pT-differential invariant cross section of electrons from heavy-flavour hadron decays in minimum-bias p–Pb collisions at sNN=5.02 TeV, comparing the results of the eID strategies in the two transition regions at 2.5 and 6 GeV/c. The centre values are slightly shifted along the pT-axis in the transition regions for better visibility. The results agree within 1%. Details on the eID strategies can be found in the text.Fig. 4The pT-differential invariant cross section of electrons from heavy-flavour hadron decays in minimum-bias p–Pb collisions at sNN=5.02 TeV. The pp reference obtained via the interpolation method is shown, not scaled by A, for comparison. The statistical uncertainties are indicated for both spectra by error bars, the systematic uncertainties are shown as boxes.Fig. 5Nuclear modification factor RpPb of electrons from heavy-flavour hadron decays as a function of transverse momentum for minimum-bias p–Pb collisions at sNN=5.02 TeV, compared with theoretical models [25,27,45,48,75], as described in the text. The vertical bars represent the statistical uncertainties, and the boxes indicate the systematic uncertainties. The systematic uncertainty from the normalisation, common to all points, is shown as a filled box at high pT.Table 1Systematic uncertainties for the different momentum intervals.Variable0.5<pT<2.5 GeV/c2.5<pT<6 GeV/c6<pT<12 GeV/cTracking4.3%2.2%3%Matching4.2%3%3.2%eID3.6%3.6%3.2% (6–8 GeV/c)5.1% (8–10 GeV/c)15.1% (10–12 GeV/c)Photonic method6.9% (0.5–1 GeV/c)2.4%4.5%3.7% (1–2.5 GeV/c)Unfolding1%1%<1%Total9.9% (0.5–1 GeV/c)5.8%7.1% (6–8 GeV/c)8.0% (1–2.5 GeV/c)8.1% (8–10 GeV/c)16.4% (10–12 GeV/c)Measurement of electrons from heavy-flavour hadron decays in p–Pb collisions at sNN=5.02TeVALICE Collaboration⋆J.Adam40D.Adamová83M.M.Aggarwal87G.Aglieri Rinella36M.Agnello110N.Agrawal48Z.Ahammed132S.U.Ahn68S.Aiola136A.Akindinov58S.N.Alam132D.Aleksandrov99B.Alessandro110D.Alexandre101R.Alfaro Molina64A.Alici12104A.Alkin3J.R.M.Almaraz119J.Alme38T.Alt43S.Altinpinar18I.Altsybeev131C.Alves Garcia Prado120C.Andrei78A.Andronic96V.Anguelov93J.Anielski54T.Antičić97F.Antinori107P.Antonioli104L.Aphecetche113H.Appelshäuser53S.Arcelli28R.Arnaldi110O.W.Arnold3792I.C.Arsene22M.Arslandok53B.Audurier113A.Augustinus36R.Averbeck96M.D.Azmi19A.Badalà106Y.W.Baek67S.Bagnasco110R.Bailhache53R.Bala90A.Baldisseri15R.C.Baral61A.M.Barbano27R.Barbera29F.Barile33G.G.Barnaföldi135L.S.Barnby101V.Barret70P.Bartalini7K.Barth36J.Bartke117E.Bartsch53M.Basile28N.Bastid70S.Basu132B.Bathen54G.Batigne113A.Batista Camejo70B.Batyunya66P.C.Batzing22I.G.Bearden80H.Beck53C.Bedda110N.K.Behera50I.Belikov55F.Bellini28H.Bello Martinez2R.Bellwied122R.Belmont134E.Belmont-Moreno64V.Belyaev75G.Bencedi135S.Beole27I.Berceanu78A.Bercuci78Y.Berdnikov85D.Berenyi135R.A.Bertens57D.Berzano36L.Betev36A.Bhasin90I.R.Bhat90A.K.Bhati87B.Bhattacharjee45J.Bhom128L.Bianchi122N.Bianchi72C.Bianchin57134J.Bielčík40J.Bielčíková83A.Bilandzic80R.Biswas4S.Biswas79S.Bjelogrlic57J.T.Blair118D.Blau99C.Blume53F.Bock9374A.Bogdanov75H.Bøggild80L.Boldizsár135M.Bombara41J.Book53H.Borel15A.Borissov95M.Borri82124F.Bossú65E.Botta27S.Böttger52C.Bourjau80P.Braun-Munzinger96M.Bregant120T.Breitner52T.A.Broker53T.A.Browning94M.Broz40E.J.Brucken46E.Bruna110G.E.Bruno33D.Budnikov98H.Buesching53S.Bufalino2736P.Buncic36O.Busch93128Z.Buthelezi65J.B.Butt16J.T.Buxton20D.Caffarri36X.Cai7H.Caines136L.Calero Diaz72A.Caliva57E.Calvo Villar102P.Camerini26F.Carena36W.Carena36F.Carnesecchi28J.Castillo Castellanos15A.J.Castro125E.A.R.Casula25C.Ceballos Sanchez9J.Cepila40P.Cerello110J.Cerkala115B.Chang123S.Chapeland36M.Chartier124J.L.Charvet15S.Chattopadhyay132S.Chattopadhyay100V.Chelnokov3M.Cherney86C.Cheshkov130B.Cheynis130V.Chibante Barroso36D.D.Chinellato121S.Cho50P.Chochula36K.Choi95M.Chojnacki80S.Choudhury132P.Christakoglou81C.H.Christensen80P.Christiansen34T.Chujo128S.U.Chung95C.Cicalo105L.Cifarelli1228F.Cindolo104J.Cleymans89F.Colamaria33D.Colella593336A.Collu7425M.Colocci28G.Conesa Balbastre71Z.Conesa del Valle51M.E.Connors136iiJ.G.Contreras40T.M.Cormier84Y.Corrales Morales110I.Cortés Maldonado2P.Cortese32M.R.Cosentino120F.Costa36P.Crochet70R.Cruz Albino11E.Cuautle63L.Cunqueiro36T.Dahms9237A.Dainese107A.Danu62D.Das100I.Das51100S.Das4A.Dash12179S.Dash48S.De120A.De Caro3112G.de Cataldo103C.de Conti120J.de Cuveland43A.De Falco25D.De Gruttola1231N.De Marco110S.De Pasquale31A.Deisting9693A.Deloff77E.Dénes135iC.Deplano81P.Dhankher48D.Di Bari33A.Di Mauro36P.Di Nezza72M.A.Diaz Corchero10T.Dietel89P.Dillenseger53R.Divià36Ø.Djuvsland18A.Dobrin5781D.Domenicis Gimenez120B.Dönigus53O.Dordic22T.Drozhzhova53A.K.Dubey132A.Dubla57L.Ducroux130P.Dupieux70R.J.Ehlers136D.Elia103H.Engel52E.Epple136B.Erazmus113I.Erdemir53F.Erhardt129B.Espagnon51M.Estienne113S.Esumi128J.Eum95D.Evans101S.Evdokimov111G.Eyyubova40L.Fabbietti9237D.Fabris107J.Faivre71A.Fantoni72M.Fasel74L.Feldkamp54A.Feliciello110G.Feofilov131J.Ferencei83A.Fernández Téllez2E.G.Ferreiro17A.Ferretti27A.Festanti30V.J.G.Feuillard1570J.Figiel117M.A.S.Figueredo124120S.Filchagin98D.Finogeev56F.M.Fionda25E.M.Fiore33M.G.Fleck93M.Floris36S.Foertsch65P.Foka96S.Fokin99E.Fragiacomo109A.Francescon3036U.Frankenfeld96U.Fuchs36C.Furget71A.Furs56M.Fusco Girard31J.J.Gaardhøje80M.Gagliardi27A.M.Gago102M.Gallio27D.R.Gangadharan74P.Ganoti8836C.Gao7C.Garabatos96E.Garcia-Solis13C.Gargiulo36P.Gasik3792E.F.Gauger118M.Germain113A.Gheata36M.Gheata6236P.Ghosh132S.K.Ghosh4P.Gianotti72P.Giubellino36110P.Giubilato30E.Gladysz-Dziadus117P.Glässel93D.M.Goméz Coral64A.Gomez Ramirez52V.Gonzalez10P.González-Zamora10S.Gorbunov43L.Görlich117S.Gotovac116V.Grabski64O.A.Grachov136L.K.Graczykowski133K.L.Graham101A.Grelli57A.Grigoras36C.Grigoras36V.Grigoriev75A.Grigoryan1S.Grigoryan66B.Grinyov3N.Grion109J.M.Gronefeld96J.F.Grosse-Oetringhaus36J.-Y.Grossiord130R.Grosso96F.Guber56R.Guernane71B.Guerzoni28K.Gulbrandsen80T.Gunji127A.Gupta90R.Gupta90R.Haake54Ø.Haaland18C.Hadjidakis51M.Haiduc62H.Hamagaki127G.Hamar135J.W.Harris136A.Harton13D.Hatzifotiadou104S.Hayashi127S.T.Heckel53M.Heide54H.Helstrup38A.Herghelegiu78G.Herrera Corral11B.A.Hess35K.F.Hetland38H.Hillemanns36B.Hippolyte55R.Hosokawa128P.Hristov36M.Huang18T.J.Humanic20N.Hussain45T.Hussain19D.Hutter43D.S.Hwang21R.Ilkaev98M.Inaba128M.Ippolitov7599M.Irfan19M.Ivanov96V.Ivanov85V.Izucheev111P.M.Jacobs74M.B.Jadhav48S.Jadlovska115J.Jadlovsky11559C.Jahnke120M.J.Jakubowska133H.J.Jang68M.A.Janik133P.H.S.Y.Jayarathna122C.Jena30S.Jena122R.T.Jimenez Bustamante96P.G.Jones101H.Jung44A.Jusko101P.Kalinak59A.Kalweit36J.Kamin53J.H.Kang137V.Kaplin75S.Kar132A.Karasu Uysal69O.Karavichev56T.Karavicheva56L.Karayan9396E.Karpechev56U.Kebschull52R.Keidel138D.L.D.Keijdener57M.Keil36M.Mohisin Khan19P.Khan100S.A.Khan132A.Khanzadeev85Y.Kharlov111B.Kileng38D.W.Kim44D.J.Kim123D.Kim137H.Kim137J.S.Kim44M.Kim44M.Kim137S.Kim21T.Kim137S.Kirsch43I.Kisel43S.Kiselev58A.Kisiel133G.Kiss135J.L.Klay6C.Klein53J.Klein9336C.Klein-Bösing54S.Klewin93A.Kluge36M.L.Knichel93A.G.Knospe118T.Kobayashi128C.Kobdaj114M.Kofarago36T.Kollegger4396A.Kolojvari131V.Kondratiev131N.Kondratyeva75E.Kondratyuk111A.Konevskikh56M.Kopcik115M.Kour90C.Kouzinopoulos36O.Kovalenko77V.Kovalenko131M.Kowalski117G.Koyithatta Meethaleveedu48I.Králik59A.Kravčáková41M.Kretz43M.Krivda59101F.Krizek83E.Kryshen36M.Krzewicki43A.M.Kubera20V.Kučera83C.Kuhn55P.G.Kuijer81A.Kumar90J.Kumar48L.Kumar87S.Kumar48P.Kurashvili77A.Kurepin56A.B.Kurepin56A.Kuryakin98M.J.Kweon50Y.Kwon137S.L.La Pointe110P.La Rocca29P.Ladron de Guevara11C.Lagana Fernandes120I.Lakomov36R.Langoy42C.Lara52A.Lardeux15A.Lattuca27E.Laudi36R.Lea26L.Leardini93G.R.Lee101S.Lee137F.Lehas81R.C.Lemmon82V.Lenti103E.Leogrande57I.León Monzón119H.León Vargas64M.Leoncino27P.Lévai135S.Li707X.Li14J.Lien42R.Lietava101S.Lindal22V.Lindenstruth43C.Lippmann96M.A.Lisa20H.M.Ljunggren34D.F.Lodato57P.I.Loenne18V.Loginov75C.Loizides74X.Lopez70E.López Torres9A.Lowe135P.Luettig53M.Lunardon30G.Luparello26A.Maevskaya56M.Mager36S.Mahajan90S.M.Mahmood22A.Maire55R.D.Majka136M.Malaev85I.Maldonado Cervantes63L.Malinina66iiiD.Mal'Kevich58P.Malzacher96A.Mamonov98V.Manko99F.Manso70V.Manzari36103M.Marchisone2765126J.Mareš60G.V.Margagliotti26A.Margotti104J.Margutti57A.Marín96C.Markert118M.Marquard53N.A.Martin96J.Martin Blanco113P.Martinengo36M.I.Martínez2G.Martínez García113M.Martinez Pedreira36A.Mas120S.Masciocchi96M.Masera27A.Masoni105L.Massacrier113A.Mastroserio33A.Matyja117C.Mayer117J.Mazer125M.A.Mazzoni108D.Mcdonald122F.Meddi24Y.Melikyan75A.Menchaca-Rocha64E.Meninno31J.Mercado Pérez93M.Meres39Y.Miake128M.M.Mieskolainen46K.Mikhaylov6658L.Milano36J.Milosevic22L.M.Minervini10323A.Mischke57A.N.Mishra49D.Miśkowiec96J.Mitra132C.M.Mitu62N.Mohammadi57B.Mohanty79132L.Molnar55113L.Montaño Zetina11E.Montes10D.A.Moreira De Godoy54113L.A.P.Moreno2S.Moretto30A.Morreale113A.Morsch36V.Muccifora72E.Mudnic116D.Mühlheim54S.Muhuri132M.Mukherjee132J.D.Mulligan136M.G.Munhoz120R.H.Munzer9237S.Murray65L.Musa36J.Musinsky59B.Naik48R.Nair77B.K.Nandi48R.Nania104E.Nappi103M.U.Naru16H.Natal da Luz120C.Nattrass125K.Nayak79T.K.Nayak132S.Nazarenko98A.Nedosekin58L.Nellen63F.Ng122M.Nicassio96M.Niculescu62J.Niedziela36B.S.Nielsen80S.Nikolaev99S.Nikulin99V.Nikulin85F.Noferini12104P.Nomokonov66G.Nooren57J.C.C.Noris2J.Norman124A.Nyanin99J.Nystrand18H.Oeschler93S.Oh136S.K.Oh67A.Ohlson36A.Okatan69T.Okubo47L.Olah135J.Oleniacz133A.C.Oliveira Da Silva120M.H.Oliver136J.Onderwaater96C.Oppedisano110R.Orava46A.Ortiz Velasquez63A.Oskarsson34J.Otwinowski117K.Oyama9376M.Ozdemir53Y.Pachmayer93P.Pagano31G.Paić63S.K.Pal132J.Pan134A.K.Pandey48P.Papcun115V.Papikyan1G.S.Pappalardo106P.Pareek49W.J.Park96S.Parmar87A.Passfeld54V.Paticchio103R.N.Patra132B.Paul100H.Pei7T.Peitzmann57H.Pereira Da Costa15E.Pereira De Oliveira Filho120D.Peresunko9975C.E.Pérez Lara81E.Perez Lezama53V.Peskov53Y.Pestov5V.Petráček40V.Petrov111M.Petrovici78C.Petta29S.Piano109M.Pikna39P.Pillot113O.Pinazza10436L.Pinsky122D.B.Piyarathna122M.Płoskoń74M.Planinic129J.Pluta133S.Pochybova135P.L.M.Podesta-Lerma119M.G.Poghosyan8486B.Polichtchouk111N.Poljak129W.Poonsawat114A.Pop78S.Porteboeuf-Houssais70J.Porter74J.Pospisil83S.K.Prasad4R.Preghenella10436F.Prino110C.A.Pruneau134I.Pshenichnov56M.Puccio27G.Puddu25P.Pujahari134V.Punin98J.Putschke134H.Qvigstad22A.Rachevski109S.Raha4S.Rajput90J.Rak123A.Rakotozafindrabe15L.Ramello32F.Rami55R.Raniwala91S.Raniwala91S.S.Räsänen46B.T.Rascanu53D.Rathee87K.F.Read12584K.Redlich77R.J.Reed134A.Rehman18P.Reichelt53F.Reidt9336X.Ren7R.Renfordt53A.R.Reolon72A.Reshetin56J.-P.Revol12K.Reygers93V.Riabov85R.A.Ricci73T.Richert34M.Richter22P.Riedler36W.Riegler36F.Riggi29C.Ristea62E.Rocco57M.Rodríguez Cahuantzi211A.Rodriguez Manso81K.Røed22E.Rogochaya66D.Rohr43D.Röhrich18R.Romita124F.Ronchetti7236L.Ronflette113P.Rosnet70A.Rossi3036F.Roukoutakis88A.Roy49C.Roy55P.Roy100A.J.Rubio Montero10R.Rui26R.Russo27E.Ryabinkin99Y.Ryabov85A.Rybicki117S.Sadovsky111K.Šafařík36B.Sahlmuller53P.Sahoo49R.Sahoo49S.Sahoo61P.K.Sahu61J.Saini132S.Sakai72M.A.Saleh134J.Salzwedel20S.Sambyal90V.Samsonov85L.Šándor59A.Sandoval64M.Sano128D.Sarkar132E.Scapparone104F.Scarlassara30C.Schiaua78R.Schicker93C.Schmidt96H.R.Schmidt35S.Schuchmann53J.Schukraft36M.Schulc40T.Schuster136Y.Schutz11336K.Schwarz96K.Schweda96G.Scioli28E.Scomparin110R.Scott125M.Šefčík41J.E.Seger86Y.Sekiguchi127D.Sekihata47I.Selyuzhenkov96K.Senosi65S.Senyukov336E.Serradilla1064A.Sevcenco62A.Shabanov56A.Shabetai113O.Shadura3R.Shahoyan36A.Shangaraev111A.Sharma90M.Sharma90M.Sharma90N.Sharma125K.Shigaki47K.Shtejer927Y.Sibiriak99S.Siddhanta105K.M.Sielewicz36T.Siemiarczuk77D.Silvermyr8434C.Silvestre71G.Simatovic129G.Simonetti36R.Singaraju132R.Singh79S.Singha13279V.Singhal132B.C.Sinha132T.Sinha100B.Sitar39M.Sitta32T.B.Skaali22M.Slupecki123N.Smirnov136R.J.M.Snellings57T.W.Snellman123C.Søgaard34J.Song95M.Song137Z.Song7F.Soramel30S.Sorensen125F.Sozzi96M.Spacek40E.Spiriti72I.Sputowska117M.Spyropoulou-Stassinaki88J.Stachel93I.Stan62G.Stefanek77E.Stenlund34G.Steyn65J.H.Stiller93D.Stocco113P.Strmen39A.A.P.Suaide120T.Sugitate47C.Suire51M.Suleymanov16M.Suljic26iR.Sultanov58M.Šumbera83A.Szabo39A.Szanto de Toledo120iI.Szarka39A.Szczepankiewicz36M.Szymanski133U.Tabassam16J.Takahashi121G.J.Tambave18N.Tanaka128M.A.Tangaro33M.Tarhini51M.Tariq19M.G.Tarzila78A.Tauro36G.Tejeda Muñoz2A.Telesca36K.Terasaki127C.Terrevoli30B.Teyssier130J.Thäder74D.Thomas118R.Tieulent130A.R.Timmins122A.Toia53S.Trogolo27G.Trombetta33V.Trubnikov3W.H.Trzaska123T.Tsuji127A.Tumkin98R.Turrisi107T.S.Tveter22K.Ullaland18A.Uras130G.L.Usai25A.Utrobicic129M.Vajzer83M.Vala59L.Valencia Palomo70S.Vallero27J.Van Der Maarel57J.W.Van Hoorne36M.van Leeuwen57T.Vanat83P.Vande Vyvre36D.Varga135A.Vargas2M.Vargyas123R.Varma48M.Vasileiou88A.Vasiliev99A.Vauthier71V.Vechernin131A.M.Veen57M.Veldhoen57A.Velure18M.Venaruzzo73E.Vercellin27S.Vergara Limón2R.Vernet8M.Verweij134L.Vickovic116G.Viesti30iJ.Viinikainen123Z.Vilakazi126O.Villalobos Baillie101A.Villatoro Tello2A.Vinogradov99L.Vinogradov131Y.Vinogradov98iT.Virgili31V.Vislavicius34Y.P.Viyogi132A.Vodopyanov66M.A.Völkl93K.Voloshin58S.A.Voloshin134G.Volpe135B.von Haller36I.Vorobyev3792D.Vranic9636J.Vrláková41B.Vulpescu70A.Vyushin98B.Wagner18J.Wagner96H.Wang57M.Wang7113D.Watanabe128Y.Watanabe127M.Weber11236S.G.Weber96D.F.Weiser93J.P.Wessels54U.Westerhoff54A.M.Whitehead89J.Wiechula35J.Wikne22M.Wilde54G.Wilk77J.Wilkinson93M.C.S.Williams104B.Windelband93M.Winn93C.G.Yaldo134H.Yang57P.Yang7S.Yano47C.Yasar69Z.Yin7H.Yokoyama128I.-K.Yoo95J.H.Yoon50V.Yurchenko3I.Yushmanov99A.Zaborowska133V.Zaccolo80A.Zaman16C.Zampolli104H.J.C.Zanoli120S.Zaporozhets66N.Zardoshti101A.Zarochentsev131P.Závada60N.Zaviyalov98H.Zbroszczyk133I.S.Zgura62M.Zhalov85H.Zhang18X.Zhang74Y.Zhang7C.Zhang57Z.Zhang7C.Zhao22N.Zhigareva58D.Zhou7Y.Zhou80Z.Zhou18H.Zhu18J.Zhu1137A.Zichichi2812A.Zimmermann93M.B.Zimmermann5436G.Zinovjev3M.Zyzak431A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, ArmeniaA.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) FoundationYerevanArmenia2Benemérita Universidad Autónoma de Puebla, Puebla, MexicoBenemérita Universidad Autónoma de PueblaPueblaMexico3Bogolyubov Institute for Theoretical Physics, Kiev, UkraineBogolyubov Institute for Theoretical PhysicsKievUkraine4Bose Institute, Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Kolkata, IndiaBose InstituteDepartment of PhysicsCentre for Astroparticle Physics and Space Science (CAPSS)KolkataIndia5Budker Institute for Nuclear Physics, Novosibirsk, RussiaBudker Institute for Nuclear PhysicsNovosibirskRussia6California Polytechnic State University, San Luis Obispo, CA, United StatesCalifornia Polytechnic State UniversitySan Luis ObispoCAUnited States7Central China Normal University, Wuhan, ChinaCentral China Normal UniversityWuhanChina8Centre de Calcul de l'IN2P3, Villeurbanne, FranceCentre de Calcul de l'IN2P3VilleurbanneFrance9Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, CubaCentro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN)HavanaCuba10Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, SpainCentro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT)MadridSpain11Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, MexicoCentro de Investigación y de Estudios Avanzados (CINVESTAV)Mexico City and MéridaMexico12Centro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, ItalyCentro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”RomeItaly13Chicago State University, Chicago, IL, USAChicago State UniversityChicagoILUSA14China Institute of Atomic Energy, Beijing, ChinaChina Institute of Atomic EnergyBeijingChina15Commissariat à l'Energie Atomique, IRFU, Saclay, FranceCommissariat à l'Energie AtomiqueIRFUSaclayFrance16COMSATS Institute of Information Technology (CIIT), Islamabad, PakistanCOMSATS Institute of Information Technology (CIIT)IslamabadPakistan17Departamento de Física de Partículas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, SpainDepartamento de Física de PartículasIGFAEUniversidad de Santiago de CompostelaSantiago de CompostelaSpain18Department of Physics and Technology, University of Bergen, Bergen, NorwayDepartment of Physics and TechnologyUniversity of BergenBergenNorway19Department of Physics, Aligarh Muslim University, Aligarh, IndiaDepartment of PhysicsAligarh Muslim UniversityAligarhIndia20Department of Physics, Ohio State University, Columbus, OH, United StatesDepartment of PhysicsOhio State UniversityColumbusOHUnited States21Department of Physics, Sejong University, Seoul, South KoreaDepartment of PhysicsSejong UniversitySeoulSouth Korea22Department of Physics, University of Oslo, Oslo, NorwayDepartment of PhysicsUniversity of OsloOsloNorway23Dipartimento di Elettrotecnica ed Elettronica del Politecnico, Bari, ItalyDipartimento di Elettrotecnica ed Elettronica del PolitecnicoBariItaly24Dipartimento di Fisica dell'Università ‘La Sapienza’ and Sezione INFN Rome, ItalyDipartimento di Fisica dell'Università‘La Sapienza’Sezione INFNRomeItaly25Dipartimento di Fisica dell'Università and Sezione INFN, Cagliari, ItalyDipartimento di Fisica dell'UniversitàSezione INFNCagliariItaly26Dipartimento di Fisica dell'Università and Sezione INFN, Trieste, ItalyDipartimento di Fisica dell'UniversitàSezione INFNTriesteItaly27Dipartimento di Fisica dell'Università and Sezione INFN, Turin, ItalyDipartimento di Fisica dell'UniversitàSezione INFNTurinItaly28Dipartimento di Fisica e Astronomia dell'Università and Sezione INFN, Bologna, ItalyDipartimento di Fisica e Astronomia dell'UniversitàSezione INFNBolognaItaly29Dipartimento di Fisica e Astronomia dell'Università and Sezione INFN, Catania, ItalyDipartimento di Fisica e Astronomia dell'UniversitàSezione INFNCataniaItaly30Dipartimento di Fisica e Astronomia dell'Università and Sezione INFN, Padova, ItalyDipartimento di Fisica e Astronomia dell'UniversitàSezione INFNPadovaItaly31Dipartimento di Fisica ‘E.R. Caianiello’ dell'Università and Gruppo Collegato INFN, Salerno, ItalyDipartimento di Fisica ‘E.R. Caianiello’ dell'UniversitàGruppo Collegato INFNSalernoItaly32Dipartimento di Scienze e Innovazione Tecnologica dell'Università del Piemonte Orientale and Gruppo Collegato INFN, Alessandria, ItalyDipartimento di Scienze e Innovazione Tecnologica dell'Università del Piemonte OrientaleGruppo Collegato INFNAlessandriaItaly33Dipartimento Interateneo di Fisica ‘M. Merlin’ and Sezione INFN, Bari, ItalyDipartimento Interateneo di Fisica ‘M. Merlin’Sezione INFNBariItaly34Division of Experimental High Energy Physics, University of Lund, Lund, SwedenDivision of Experimental High Energy PhysicsUniversity of LundLundSweden35Eberhard Karls Universität Tübingen, Tübingen, GermanyEberhard Karls Universität TübingenTübingenGermany36European Organization for Nuclear Research (CERN), Geneva, SwitzerlandEuropean Organization for Nuclear Research (CERN)GenevaSwitzerland37Excellence Cluster Universe, Technische Universität München, Munich, GermanyExcellence Cluster UniverseTechnische Universität MünchenMunichGermany38Faculty of Engineering, Bergen University College, Bergen, NorwayFaculty of EngineeringBergen University CollegeBergenNorway39Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, SlovakiaFaculty of Mathematics, Physics and InformaticsComenius UniversityBratislavaSlovakia40Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech RepublicFaculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PraguePragueCzech Republic41Faculty of Science, P.J. Šafárik University, Košice, SlovakiaFaculty of ScienceP.J. Šafárik UniversityKošiceSlovakia42Faculty of Technology, Buskerud and Vestfold University College, Vestfold, NorwayFaculty of TechnologyBuskerud and Vestfold University CollegeVestfoldNorway43Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyFrankfurt Institute for Advanced StudiesJohann Wolfgang Goethe-Universität FrankfurtFrankfurtGermany44Gangneung-Wonju National University, Gangneung, South KoreaGangneung-Wonju National UniversityGangneungSouth Korea45Gauhati University, Department of Physics, Guwahati, IndiaGauhati UniversityDepartment of PhysicsGuwahatiIndia46Helsinki Institute of Physics (HIP), Helsinki, FinlandHelsinki Institute of Physics (HIP)HelsinkiFinland47Hiroshima University, Hiroshima, JapanHiroshima UniversityHiroshimaJapan48Indian Institute of Technology Bombay (IIT), Mumbai, IndiaIndian Institute of Technology Bombay (IIT)MumbaiIndia49Indian Institute of Technology Indore, Indore (IITI), IndiaIndian Institute of Technology IndoreIndore (IITI)India50Inha University, Incheon, South KoreaInha UniversityIncheonSouth Korea51Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud, CNRS-IN2P3, Orsay, FranceInstitut de Physique Nucléaire d'Orsay (IPNO)Université Paris-SudCNRS-IN2P3OrsayFrance52Institut für Informatik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyInstitut für InformatikJohann Wolfgang Goethe-Universität FrankfurtFrankfurtGermany53Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, GermanyInstitut für KernphysikJohann Wolfgang Goethe-Universität FrankfurtFrankfurtGermany54Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, GermanyInstitut für KernphysikWestfälische Wilhelms-Universität MünsterMünsterGermany55Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, CNRS-IN2P3, Strasbourg, FranceInstitut Pluridisciplinaire Hubert Curien (IPHC)Université de StrasbourgCNRS-IN2P3StrasbourgFrance56Institute for Nuclear Research, Academy of Sciences, Moscow, RussiaInstitute for Nuclear ResearchAcademy of SciencesMoscowRussia57Institute for Subatomic Physics of Utrecht University, Utrecht, NetherlandsInstitute for Subatomic Physics of Utrecht UniversityUtrechtNetherlands58Institute for Theoretical and Experimental Physics, Moscow, RussiaInstitute for Theoretical and Experimental PhysicsMoscowRussia59Institute of Experimental Physics, Slovak Academy of Sciences, Košice, SlovakiaInstitute of Experimental PhysicsSlovak Academy of SciencesKošiceSlovakia60Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech RepublicInstitute of PhysicsAcademy of Sciences of the Czech RepublicPragueCzech Republic61Institute of Physics, Bhubaneswar, IndiaInstitute of PhysicsBhubaneswarIndia62Institute of Space Science (ISS), Bucharest, RomaniaInstitute of Space Science (ISS)BucharestRomania63Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, MexicoInstituto de Ciencias NuclearesUniversidad Nacional Autónoma de MéxicoMexico CityMexico64Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, MexicoInstituto de FísicaUniversidad Nacional Autónoma de MéxicoMexico CityMexico65iThemba LABS, National Research Foundation, Somerset West, South AfricaiThemba LABSNational Research FoundationSomerset WestSouth Africa66Joint Institute for Nuclear Research (JINR), Dubna, RussiaJoint Institute for Nuclear Research (JINR)DubnaRussia67Konkuk University, Seoul, South KoreaKonkuk UniversitySeoulSouth Korea68Korea Institute of Science and Technology Information, Daejeon, South KoreaKorea Institute of Science and Technology InformationDaejeonSouth Korea69KTO Karatay University, Konya, TurkeyKTO Karatay UniversityKonyaTurkey70Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS-IN2P3, Clermont-Ferrand, FranceLaboratoire de Physique Corpusculaire (LPC)Clermont UniversitéUniversité Blaise PascalCNRS-IN2P3Clermont-FerrandFrance71Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS-IN2P3, Grenoble, FranceLaboratoire de Physique Subatomique et de CosmologieUniversité Grenoble-AlpesCNRS-IN2P3GrenobleFrance72Laboratori Nazionali di Frascati, INFN, Frascati, ItalyLaboratori Nazionali di FrascatiINFNFrascatiItaly73Laboratori Nazionali di Legnaro, INFN, Legnaro, ItalyLaboratori Nazionali di LegnaroINFNLegnaroItaly74Lawrence Berkeley National Laboratory, Berkeley, CA, United StatesLawrence Berkeley National LaboratoryBerkeleyCAUnited States75Moscow Engineering Physics Institute, Moscow, RussiaMoscow Engineering Physics InstituteMoscowRussia76Nagasaki Institute of Applied Science, Nagasaki, JapanNagasaki Institute of Applied ScienceNagasakiJapan77National Centre for Nuclear Studies, Warsaw, PolandNational Centre for Nuclear StudiesWarsawPoland78National Institute for Physics and Nuclear Engineering, Bucharest, RomaniaNational Institute for Physics and Nuclear EngineeringBucharestRomania79National Institute of Science Education and Research, Bhubaneswar, IndiaNational Institute of Science Education and ResearchBhubaneswarIndia80Niels Bohr Institute, University of Copenhagen, Copenhagen, DenmarkNiels Bohr InstituteUniversity of CopenhagenCopenhagenDenmark81Nikhef, Nationaal Instituut voor Subatomaire Fysica, Amsterdam, NetherlandsNikhefNationaal Instituut voor Subatomaire FysicaAmsterdamNetherlands82Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, United KingdomNuclear Physics GroupSTFC Daresbury LaboratoryDaresburyUnited Kingdom83Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy, Czech RepublicNuclear Physics InstituteAcademy of Sciences of the Czech RepublicŘež u PrahyCzech Republic84Oak Ridge National Laboratory, Oak Ridge, TN, United StatesOak Ridge National LaboratoryOak RidgeTNUnited States85Petersburg Nuclear Physics Institute, Gatchina, RussiaPetersburg Nuclear Physics InstituteGatchinaRussia86Physics Department, Creighton University, Omaha, NE, United StatesPhysics DepartmentCreighton UniversityOmahaNEUnited States87Physics Department, Panjab University, Chandigarh, IndiaPhysics DepartmentPanjab UniversityChandigarhIndia88Physics Department, University of Athens, Athens, GreecePhysics DepartmentUniversity of AthensAthensGreece89Physics Department, University of Cape Town, Cape Town, South AfricaPhysics DepartmentUniversity of Cape TownCape TownSouth Africa90Physics Department, University of Jammu, Jammu, IndiaPhysics DepartmentUniversity of JammuJammuIndia91Physics Department, University of Rajasthan, Jaipur, IndiaPhysics DepartmentUniversity of RajasthanJaipurIndia92Physik Department, Technische Universität München, Munich, GermanyPhysik DepartmentTechnische Universität MünchenMunichGermany93Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, GermanyPhysikalisches InstitutRuprecht-Karls-Universität HeidelbergHeidelbergGermany94Purdue University, West Lafayette, IN, United StatesPurdue UniversityWest LafayetteINUnited States95Pusan National University, Pusan, South KoreaPusan National UniversityPusanSouth Korea96Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, GermanyResearch DivisionExtreMe Matter Institute EMMIGSI Helmholtzzentrum für SchwerionenforschungDarmstadtGermany97Rudjer Bošković Institute, Zagreb, CroatiaRudjer Bošković InstituteZagrebCroatia98Russian Federal Nuclear Center (VNIIEF), Sarov, RussiaRussian Federal Nuclear Center (VNIIEF)SarovRussia99Russian Research Centre Kurchatov Institute, Moscow, RussiaRussian Research Centre Kurchatov InstituteMoscowRussia100Saha Institute of Nuclear Physics, Kolkata, IndiaSaha Institute of Nuclear PhysicsKolkataIndia101School of Physics and Astronomy, University of Birmingham, Birmingham, United KingdomSchool of Physics and AstronomyUniversity of BirminghamBirminghamUnited Kingdom102Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, PeruSección FísicaDepartamento de CienciasPontificia Universidad Católica del PerúLimaPeru103Sezione INFN, Bari, ItalySezione INFNBariItaly104Sezione INFN, Bologna, ItalySezione INFNBolognaItaly105Sezione INFN, Cagliari, ItalySezione INFNCagliariItaly106Sezione INFN, Catania, ItalySezione INFNCataniaItaly107Sezione INFN, Padova, ItalySezione INFNPadovaItaly108Sezione INFN, Rome, ItalySezione INFNRomeItaly109Sezione INFN, Trieste, ItalySezione INFNTriesteItaly110Sezione INFN, Turin, ItalySezione INFNTurinItaly111SSC IHEP of NRC Kurchatov institute, Protvino, RussiaSSC IHEP of NRC Kurchatov instituteProtvinoRussia112Stefan Meyer Institut für Subatomare Physik (SMI), Vienna, AustriaStefan Meyer Institut für Subatomare Physik (SMI)ViennaAustria113SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS-IN2P3, Nantes, FranceSUBATECHEcole des Mines de NantesUniversité de NantesCNRS-IN2P3NantesFrance114Suranaree University of Technology, Nakhon Ratchasima, ThailandSuranaree University of TechnologyNakhon RatchasimaThailand115Technical University of Košice, Košice, SlovakiaTechnical University of KošiceKošiceSlovakia116Technical University of Split FESB, Split, CroatiaTechnical University of Split FESBSplitCroatia117The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, PolandThe Henryk Niewodniczanski Institute of Nuclear PhysicsPolish Academy of SciencesCracowPoland118The University of Texas at Austin, Physics Department, Austin, TX, USAThe University of Texas at AustinPhysics DepartmentAustinTXUSA119Universidad Autónoma de Sinaloa, Culiacán, MexicoUniversidad Autónoma de SinaloaCuliacánMexico120Universidade de São Paulo (USP), São Paulo, BrazilUniversidade de São Paulo (USP)São PauloBrazil121Universidade Estadual de Campinas (UNICAMP), Campinas, BrazilUniversidade Estadual de Campinas (UNICAMP)CampinasBrazil122University of Houston, Houston, TX, United StatesUniversity of HoustonHoustonTXUnited States123University of Jyväskylä, Jyväskylä, FinlandUniversity of JyväskyläJyväskyläFinland124University of Liverpool, Liverpool, United KingdomUniversity of LiverpoolLiverpoolUnited Kingdom125University of Tennessee, Knoxville, TN, United StatesUniversity of TennesseeKnoxvilleTNUnited States126University of the Witwatersrand, Johannesburg, South AfricaUniversity of the WitwatersrandJohannesburgSouth Africa127University of Tokyo, Tokyo, JapanUniversity of TokyoTokyoJapan128University of Tsukuba, Tsukuba, JapanUniversity of TsukubaTsukubaJapan129University of Zagreb, Zagreb, CroatiaUniversity of ZagrebZagrebCroatia130Université de Lyon, Université Lyon 1, CNRS/IN2P3, IPN-Lyon, Villeurbanne, FranceUniversité de LyonUniversité Lyon 1CNRS/IN2P3IPN-LyonVilleurbanneFrance131V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, RussiaV. Fock Institute for PhysicsSt. Petersburg State UniversitySt. PetersburgRussia132Variable Energy Cyclotron Centre, Kolkata, IndiaVariable Energy Cyclotron CentreKolkataIndia133Warsaw University of Technology, Warsaw, PolandWarsaw University of TechnologyWarsawPoland134Wayne State University, Detroit, MI, United StatesWayne State UniversityDetroitMIUnited States135Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, HungaryWigner Research Centre for PhysicsHungarian Academy of SciencesBudapestHungary136Yale University, New Haven, CT, United StatesYale UniversityNew HavenCTUnited States137Yonsei University, Seoul, South KoreaYonsei UniversitySeoulSouth Korea138Zentrum für Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, GermanyZentrum für Technologietransfer und Telekommunikation (ZTT)Fachhochschule WormsWormsGermanyiDeceased.iiAlso at: Georgia State University, Atlanta, Georgia, United States.iiiAlso at: M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear, Physics, Moscow, Russia.⋆E-mail address: alice-publications@cern.ch.Editor: L. RolandiAbstractThe production of electrons from heavy-flavour hadron decays was measured as a function of transverse momentum (pT) in minimum-bias p–Pb collisions at sNN=5.02 TeV using the ALICE detector at the LHC. The measurement covers the pT interval 0.5<pT<12 GeV/c and the rapidity range −1.065<ycms<0.135 in the centre-of-mass reference frame. The contribution of electrons from background sources was subtracted using an invariant mass approach. The nuclear modification factor RpPb was calculated by comparing the pT-differential invariant cross section in p–Pb collisions to a pp reference at the same centre-of-mass energy, which was obtained by interpolating measurements at s=2.76 TeV and s=7 TeV. The RpPb is consistent with unity within uncertainties of about 25%, which become larger for pT below 1 GeV/c. The measurement shows that heavy-flavour production is consistent with binary scaling, so that a suppression in the high-pT yield in Pb–Pb collisions has to be attributed to effects induced by the hot medium produced in the final state. The data in p–Pb collisions are described by recent model calculations that include cold nuclear matter effects.1IntroductionThe Quark-Gluon Plasma (QGP) [1,2], a colour-deconfined state of strongly-interacting matter, is predicted to exist at high temperature according to lattice Quantum Chromodynamics (QCD) calculations [3]. These conditions can be reached in ultra-relativistic heavy-ion collisions [4–10]. Charm and beauty (heavy-flavour) quarks are mostly produced in initial hard scattering processes on a very short time scale, shorter than the formation time of the QGP medium [11], and thus experience the full temporal and spatial evolution of the collision. While interacting with the QGP medium, heavy quarks lose energy via elastic and radiative processes [12–14]. Heavy-flavour hadrons are therefore well-suited probes to study the properties of the QGP. The effect of energy loss on heavy-flavour production can be characterised via the nuclear modification factor (RAA) of heavy-flavour hadrons. The RAA is defined as the ratio of the heavy-flavour hadron yield in nucleus–nucleus (A–A) collisions to that in proton–proton (pp) collisions scaled by the average number of binary nucleon–nucleon collisions. The RAA is studied differentially as a function of transverse momentum (pT), rapidity (y) and collision centrality. It was measured at the Relativistic Heavy Ion Collider (RHIC) [15–18] and at the Large Hadron Collider (LHC) [19–22]. At RHIC, in central Au–Au collisions at sNN=200 GeV the RAA of charmed mesons and of electrons from heavy-flavour hadron decays shows that their production is strongly suppressed by a factor of about 5 for pT>3 GeV/c at mid-rapidity. For the most central Pb–Pb collisions at sNN=2.76 TeV at the LHC, a suppression by a factor of 5–6 is observed for charmed mesons for pT>5 GeV/c at mid-rapidity [22].The interpretation of the measurements in A–A collisions requires the study of heavy-flavour production in p–A collisions, which provides access to cold nuclear matter (CNM) effects. These effects are not related to the formation of a colour-deconfined medium, but are present in case of colliding nuclei (or proton–nucleus). An important CNM effect in the initial state is parton-density shadowing or saturation, which can be described using modified parton distribution functions (PDF) in the nucleus [23] or using the Color Glass Condensate (CGC) effective theory [24]. Further CNM effects include energy loss [25] in the initial and final states and a Cronin-like enhancement [26] as a consequence of multiple scatterings [25,27].The influence of the CNM effects can be studied by measuring the nuclear modification factor RpA. Like the RAA, the RpA is defined such that it is unity if there are no nuclear effects. For minimum-bias p–A collisions, it can be expressed as [28](1)RpA=1AdσpA/dpTdσpp/dpT , where dσpA/dpT and dσpp/dpT are the pT-differential production cross sections of a given particle species in p–A and pp collisions, respectively, and A is the number of nucleons in the nucleus.Cold nuclear matter effects were recently investigated at the RHIC and the LHC [29–44]. At RHIC, the nuclear modification factor of electrons from heavy-flavour hadron decays in central d–Au collisions (0–20%) at sNN=200 GeV is larger than unity at mid-rapidity in the transverse momentum interval 1.5<pT<5 GeV/c [42]. The corresponding measurement for muons from heavy-flavour hadron decays in central d–Au collisions shows a suppression at forward rapidity and an enhancement at backward rapidity [43]. Theoretical models that include the modification of the PDF in the nucleus can neither explain the enhancement nor the large difference between forward and backward rapidity. Possible explanations include the Cronin-like enhancement [26] due to radial flow of heavy mesons [45]. At the LHC, the pT-differential nuclear modification factor RpPb of D mesons measured in p–Pb collisions at sNN=5.02 TeV [44] is consistent with unity for pT>1 GeV/c and is described by theoretical calculations that include gluon saturation effects. Both at RHIC and at the LHC, the p/d–A measurements indicate that initial-state effects alone cannot explain the strong suppression seen at high-pT in nucleus–nucleus collisions.In this Letter, the pT-differential invariant cross section and the nuclear modification factor RpPb of electrons from heavy-flavour hadron decays measured in minimum-bias p–Pb collisions at sNN=5.02 TeV with ALICE at the LHC are presented. The measurement covers the rapidity range −1.065<ycms<0.135 in the centre-of-mass system (cms) for electrons with transverse momentum 0.5<pT<12 GeV/c. This rapidity coverage results from the same rigidity of the p and Pb beams at the LHC, leading to a rapidity shift of |yNN|=0.465 between the nucleon–nucleon cms and the laboratory reference frame, in the direction of the p beam. At low pT, the measurement probes the production of charm-hadron decays [46], providing sensitivity to the gluon PDF in the regime of Bjorken-x of the order of 10−4 [47], where a substantial shadowing effect is expected [48].To obtain the nuclear modification factor RpPb of electrons from heavy-flavour hadron decays, the pT-differential invariant cross section in p–Pb collisions at sNN=5.02 TeV was compared to a pp reference multiplied by 208, the Pb mass number. The pp reference was obtained by interpolating the pT-differential cross section measurements at s=2.76 TeV and 7 TeV.The Letter is organised as follows. The experimental apparatus, data sample and event selection are described in Section 2. The electron reconstruction strategy and the pp reference spectrum are explained in Sections 3 and 4, respectively. The measured pT-differential invariant cross section, the nuclear modification factor RpPb of electrons from heavy-flavour hadron decays and comparison of RpPb to model calculations are reported in Section 5.2Experimental apparatus, data sample and event selectionA detailed description of the ALICE apparatus can be found in [49,50]. Electrons are reconstructed at mid-rapidity using the central barrel detectors (described below) located inside a solenoid magnet, which generates a magnetic field B=0.5 T along the beam direction.The Inner Tracking System (ITS), the closest detector to the interaction point, includes six cylindrical layers of silicon detectors with three different technologies (pixel, drift and strip) at radii between 3.9 cm and 43 cm with a pseudorapidity coverage in the laboratory reference frame in the full azimuth between |ηlab|< 2.0 at small radii and |ηlab|< 0.9 at large radii [49,51]. The two innermost layers form the Silicon Pixel Detector (SPD), which plays a key role in primary and secondary vertex reconstruction. At an incident angle perpendicular to the detector surfaces, the total material budget of the ITS corresponds on average to 7.7% of a radiation length [51]. The main tracking device in the central barrel is the Time Projection Chamber (TPC) [52], which surrounds the ITS and covers a pseudorapidity range of |ηlab|< 0.9 in the full azimuth. The track reconstruction proceeds inward from the outer radius of the TPC to the innermost layer of the ITS [50]. The TPC provides particle identification via the measurement of the specific energy loss dE/dx. The Time-Of-Flight array (TOF), based on Multi-gap Resistive Plate Chambers, covers the full azimuth and |ηlab|< 0.9 at a radial distance of 3.7 m from the interaction point [53]. Using the particle time-of-flight measurement, electrons can be distinguished from hadrons for pT≤2.5 GeV/c. The collision time, used for the calculation of the time-of-flight to the TOF detector, is measured by an array of Cherenkov counters, the T0 detector, located at +350 cm and −70 cm from the interaction point along the beam direction [54]. The Electromagnetic Calorimeter (EMCal), situated behind the TOF, is a sampling calorimeter based on Shashlik technology [55]. Its geometrical acceptance is 107° in azimuth and |ηlab|< 0.7. In this analysis, the azimuthal angle and η coverage were limited to 100° and 0.6, respectively, to ensure uniform detector performance.The minimum-bias (MB) p–Pb data sample used in this analysis was collected in 2013. The trigger condition required a coincidence of signals between the two V0 scintillator hodoscopes, placed on either side of the interaction point at 2.8<ηlab<5.1 and −3.7<ηlab<−1.7, synchronised with the passage of bunches from both beams [54]. The background due to interactions of one of the two beams and residual particles in the beam vacuum tube was rejected in the offline event selection by correlating the time information of the V0 detectors with that from the two Zero Degree Calorimeters (ZDC) [50], that are located 112.5 m away from the interaction point along the beam pipe, symmetrically on either side. The primary vertex was reconstructed with tracks in the ITS and the TPC [50]. Events with a primary vertex located farther than ±10 cm from the centre of the interaction region along the beam direction were rejected. About 10% of the events do not fulfil this selection criterion. A sample of 100 million events passed the offline event selection, corresponding to an integrated luminosity Lint=47.8±1.6 μb−1, given the cross section σMBV0=2.09±0.07 b for the minimum-bias V0 trigger condition [56]. The efficiency for the trigger condition and offline event selection is larger than 99% for non-single-diffractive (NSD) p–Pb collisions [57].3AnalysisA combination of electron identification (eID) strategies with different detectors offers the largest pT reach for the measurement of electrons from heavy-flavour hadron decays. In particular, it ensures that the systematic uncertainties and the hadron contamination are small over the whole transverse momentum range. Throughout the paper, the term ‘electron’ is used for electrons and positrons. The capability of the TPC to identify electrons via specific energy loss dE/dx in the detector was used over the whole momentum range 0.5<pT<12 GeV/c. However, it is subject to ambiguous identification of hadrons (pions, kaons, protons and deuterons) below 2.5 GeV/c and above 6 GeV/c in transverse momentum. At low transverse momentum (0.5<pT<2.5 GeV/c), these ambiguities were resolved by measuring the time-of-flight of the particle from the interaction region to the TOF detector and combining it with the momentum measurement, to determine the particle mass. In the high momentum region (6<pT<12 GeV/c), the EMCal was used to reduce the hadron contamination. Electrons are separated from hadrons by calculating the ratio of the energy deposited (E) in the EMCal to the momentum (p). Since electrons deposit all of their energy in the EMCal, the ratio E/p is around unity for electrons, while the ratio for charged hadrons is much smaller on average.The selection criteria for charged-particle tracks are similar to those applied in previous analyses measuring the production of electrons from heavy-flavour hadron decays in pp collisions [58,59]. In order to have optimal eID performance with the TPC, the analysis was restricted to the pseudorapidity range |ηlab|<0.6 in the laboratory frame for electrons with transverse momentum 0.5<pT<12 GeV/c. Up to a pT of 6 GeV/c, a signal in the innermost layer of the SPD was required in order to reduce the background from photon conversions. In addition, this selection was further constrained by requiring hits in both SPD layers, to reduce the number of incorrect matches between candidate tracks and hits reconstructed in the first layer of the SPD. At high pT, where the EMCal was used, tracks with hits in either of the SPD layers were selected in order to minimise the effect of dead areas of the first SPD layer within the acceptance region of the EMCal, as in previous analyses [58,59].The electron identification with TPC and TOF was based on the number of standard deviations (nσTPC or nσTOF) for the specific energy loss and time-of-flight measurements, respectively. The nσ variable is computed as a difference between the measured signal and the expected one for electrons divided by the energy loss (σTPC) or time-of-flight (σTOF) resolution. The expected signal and resolution originate from parametrisations of the detector signal, which are described in detail in [50]. In the transverse momentum interval 0.5<pT<2.5 GeV/c, particles were identified as electrons if they satisfied −0.5<nσTPC<3, which yields an identification efficiency of 69%. In the transverse momentum interval 2.5<pT<6 GeV/c, a tighter selection criterion of 0<nσTPC<3 was applied (with an eID efficiency of 50%) to reduce the hadron contamination at higher transverse momentum. To resolve the aforementioned ambiguities at low transverse momentum (pT≤2.5 GeV/c), only tracks with |nσTOF|<3 were accepted. Fig. 1(a) shows the measured dE/dx in the TPC with respect to the expected dE/dx for electrons normalised to the expected resolution σTPC after the eID with TOF. The solid lines indicate the selection criteria used for the transverse momentum interval 0.5<pT<2.5 GeV/c, indicating that the hadron contamination within the resulting electron candidate sample is small. In the high momentum region (6<pT<12 GeV/c), electrons were selected if they satisfied −1<nσTPC<3 and 0.8<E/p<1.2 (see Fig. 1(b)).The hadron contamination in the electron candidate sample was determined by parametrising the TPC signal in momentum slices for pT≤6 GeV/c as done in previous analyses [58,59]. In the transverse momentum interval 6<pT<12 GeV/c, the E/p distribution for hadrons identified via the specific energy loss measured in the TPC (nσTPC<−3.5) was normalised in the lower E/p range (0.4–0.6) to the corresponding E/p distribution for identified electrons (−1<nσTPC<3) (see Fig. 1(b)). The number of hadrons with an E/p ratio between 0.8 and 1.2 was thus determined in momentum slices. The hadron contamination ranged from 2% at 5<pT<6 GeV/c to 15% at 10<pT<12 GeV/c and was correspondingly subtracted. For pT<5 GeV/c, the contamination was found to be negligible.The resulting electron candidate sample, also referred to as the ‘inclusive electron sample’ in the following, still contains electrons from sources other than heavy-flavour hadron decays. The majority of the remaining background originates from photon conversions in the detector material (γ→e+e−) and Dalitz decays of neutral mesons, e.g. π0→γe+e− and η→γe+e−. These electrons are hereafter denoted as ‘photonic electrons’.In previous analyses of electrons from heavy-flavour hadron decays in pp collisions by the ALICE Collaboration, the contribution of electrons from background sources was estimated via a data-tuned Monte Carlo cocktail and subtracted from the inclusive electron sample [58,59]. The pion input to the cocktail was based on pion measurements with ALICE [60,61], while heavier mesons were implemented via mT scaling [62], and photons from hard scattering processes (direct γ, γ⁎) were obtained from next-to-leading order (NLO) calculations [63]. The resulting systematic uncertainty of the sum of all background sources was large, in particular at low pT, where the signal-to-background ratio is small [58,59]. In order to reduce this uncertainty, in this analysis an invariant mass technique [16] was used to estimate the number of electrons coming from background sources.Photonic electrons are produced in e+e− pairs and can thus be identified using an invariant mass technique (photonic method). All inclusive electrons were paired with other tracks in the same event passing looser track selection and electron identification criteria (e.g. −3<nσTPC<3). Looser selection criteria were applied to increase the efficiency to find the photonic partner. Fig. 2 shows the invariant mass distributions of unlike-sign and like-sign electron pairs for the inclusive electron in the interval 0.5<pT<0.6 GeV/c. The like-sign distribution estimates the uncorrelated pairs. Subtracting these from the unlike-sign pairs yields the number of electrons with a photonic partner Nphotraw (see Fig. 2). An invariant mass smaller than 0.14 GeV/c2 was required. According to simulations, the peak around zero in the photonic electron pair distribution is due to photon conversions; the exponential tail to higher values originates from Dalitz decays of neutral mesons.The efficiency εphot to find photonic electron pairs was estimated using Monte Carlo simulations. A sample of p–Pb collisions was generated with HIJING v1.36 [64]. To increase the statistical precision at high pT, one cc‾ or bb‾ pair decaying semileptonically using the generator PYTHIA v6.4.21 [65] with the Perugia-0 tune [66] was added in each event. The generated particles were propagated through the apparatus using GEANT3 [67] and a realistic detector response was applied to reproduce the performance of the detector system during data taking period. The simulated transverse momentum distributions of the π0 and η mesons were weighted to match the measured shapes, where the π0 input was based on the measured charged-pion spectra [68,69] assuming Nπ0=1/2(Nπ++Nπ−) and the η input was derived via mT scaling. The efficiency εphot is defined as the fraction of electrons from photonic origin for which the partner could be found within the defined acceptance of the analysis, i.e. the geometrical acceptance of the ALICE apparatus together with the superimposed track selection and electron identification criteria. The efficiency εphot increases sharply with pT from 35% to 80% between 0.5 and 3 GeV/c and remains at 80% up to 12 GeV/c. The raw photonic electron distribution Nphotraw was then corrected by the efficiency εphot as Nphot(pT)=Nphotraw(pT)/εphot(pT) and subtracted from the inclusive electron yield to obtain the yield of electrons from heavy-flavour hadron decays. The signal-to-background ratio (ratio of non-photonic to photonic yield) ranges from 0.2 at 0.5 GeV/c to 4 at 10 GeV/c.The remaining electrons are then those from semileptonic heavy-flavour hadron decays (Nhferaw), besides a small residual background contribution originating from semileptonic kaon decays and dielectron decays of J/ψ mesons. The latter is the only non-negligible contribution from quarkonia. These contributions were subtracted from the corrected invariant cross section, as described later on in this section.The pT-differential invariant cross section σhfe of electrons from heavy-flavour hadron decays, 1/2(e++e−), was calculated as(2)12πpTd2σhfedpTdy=121ΔφpTcentre1ΔyΔpTcunfoldNhferaw(ϵgeo×ϵreco×ϵeID)σMBV0NMB, where pTcentre are the centres of the pT bins with widths ΔpT, and Δφ and Δy denote the geometrical acceptance in azimuth and rapidity to which the analysis was restricted, respectively. NMB is the number of events that pass the selection criteria described in Section 2 and σMBV0 is the p–Pb cross section for the minimum-bias V0 trigger condition. The raw spectrum of electrons from heavy-flavour hadron decays (Nhferaw) was corrected for the acceptance of the detectors in the selected geometrical region of the analysis (ϵgeo), the track reconstruction and selection efficiency (ϵreco), and the eID efficiency (ϵeID). These corrections were computed using the aforementioned Monte Carlo simulations. Only the efficiency of the TPC electron identification selection criterion for pT<6 GeV/c was determined using a data-driven approach based on the nσTPC distribution [59]. The measurement of the electron pT is affected by the finite momentum resolution and by electron energy loss due to bremsstrahlung in the detector material [49], which is not corrected for in the track reconstruction algorithm. These effects distort the shape of the pT distribution, which falls steeply with increasing momentum. To determine this correction (cunfold), an iterative unfolding procedure based on Bayes' theorem was applied [70,71].The aforementioned residual background contributions, electrons from semileptonic kaon decays and dielectron decays of J/ψ mesons, were estimated as an invariant cross section with Monte Carlo simulations and found to be less than 3% per pT bin and subtracted from the corrected invariant cross section of non-photonic electrons. More specifically, the contribution from J/ψ mesons was implemented by using a parametrisation for pp collisions based on the interpolation of J/ψ measurements from RHIC at s=200 GeV, Tevatron at s=1.96 TeV, and the LHC at s=7 TeV according to [72]. Decays of J/ψ mesons within |ylab|< 1.0 were considered. The parametrisation and its associated systematic uncertainty were scaled from pp to p–Pb collisions assuming binary collision scaling. Potential deviations from binary collision scaling were considered by assigning a 50% systematic uncertainty on the normalisation. The parametrisation with its uncertainties used as input for the Monte Carlo simulations is consistent with the measured J/ψ cross section in p–Pb collisions [38].The systematic uncertainties were estimated as a function of pT by repeating the analysis with different selection criteria. The systematic uncertainties were evaluated for the spectrum obtained after the subtraction of the photonic yield Nphot from the inclusive spectrum and before removing the remaining background contributions originating from semileptonic kaon decays and dielectron decays of J/ψ mesons. The sources of systematic uncertainty for the inclusive analysis and the determination of the electron background are listed in Table 1.The systematic uncertainties for tracking and eID are pT dependent due to the usage of the various detectors in the different momentum intervals. The latter also includes the uncertainties due to the determination of the hadron contamination. The 3% systematic uncertainty for the matching between ITS and TPC was taken from [73], where the matching efficiency of charged particles in data was compared to Monte Carlo simulations. The uncertainty of the TOF-TPC matching efficiency was estimated by comparing the matching efficiency in data and Monte Carlo simulations using electrons from photon conversions, which were identified via topological cuts. The uncertainty amounts to 3%. The TPC-EMCal matching uncertainty was assigned to be 1%, as determined by varying the size of the matching window in η and azimuth φ for charged-particle tracks that were extrapolated to the calorimeter. The resulting matching uncertainties were combined in quadrature for the various pT intervals shown in Table 1.The listed uncertainties for the photonic method include the uncertainties on eID and tracking. In addition, the Monte Carlo sample was divided into two halves. The first was treated as real data and the second was used to correct the resulting spectrum. Deviations from the expected pT spectrum of electrons from heavy-flavour hadron decays resulted in a 2% systematic uncertainty for pT≤6 GeV/c and 4% above. The uncertainty on the re-weighting of the π0- and η-meson pT distributions in Monte Carlo simulations was estimated by changing the weights by ±10%. The variation yielded a 2% uncertainty for pT≤2.5 GeV/c on the pT-differential invariant cross section of electrons from heavy-flavour hadron decays. This source of uncertainty is negligible at higher pT. The invariant mass technique gives a systematic uncertainty smaller by a factor of ≥4 and of about 1.4 for pT≤1 GeV/c and 3<pT<12 GeV/c, respectively, compared to the one of the cocktail subtraction method [59]. The reduction in uncertainty, in particular at low pT, proves the advantage of using the invariant mass technique for the estimation of electrons from background sources.The uncertainty of the pT unfolding procedure was determined by employing an alternative unfolding method (matrix inversion) and, as described in [59], by correcting the data with two different Monte Carlo samples corresponding to different pT distributions. In addition to the aforementioned signal-enhanced Monte Carlo sample, a minimum-bias sample was used. The comparison of the resulting pT spectra revealed an uncertainty of 1% for pT≤6 GeV/c, and smaller than 1% above 6 GeV/c. The systematic uncertainties of the heavy-flavour electron yield due to the subtraction of the remaining background originating from semileptonic kaon decays and dielectron decays from J/ψ mesons are smaller than 0.5%. This was estimated by changing the particle yields by ±50% and ±100% for the J/ψ meson and the semileptonic kaon decays, respectively.The individual sources of systematic uncertainties are uncorrelated. Therefore, they were added in quadrature to give a total systematic uncertainty ranging from 5.8% to 16.4% depending on the pT bin. The normalisation uncertainty on the luminosity is of 3.7% [56].Fig. 3 shows the interval 2.5<pT<8 GeV/c of the pT-differential invariant cross section of electrons from heavy-flavour hadron decays in minimum-bias p–Pb collisions at sNN=5.02 TeV, comparing the results of the various eID strategies in the two transition regions at 2.5 GeV/c and 6 GeV/c. A consistency within 1% is found.4pp referenceIn order to calculate the nuclear modification factor RpPb, a reference cross section for pp collisions at the same centre-of-mass energy is needed. Since pp data at s=5.02 TeV are currently not available, the reference was obtained by interpolating the pT-differential cross sections of electrons from heavy-flavour hadron decays measured in pp collisions at s=2.76 TeV and at s=7 TeV [58,59]. The analysis described in this paper requires a reference in the interval 0.5<pT<12 GeV/c. While the s=2.76 TeV analysis was carried out in this pT range, the s=7 TeV measurement is limited to the pT interval 0.5<pT<8 GeV/c. Thus, to extend the pT interval up to 12 GeV/c a measurement by the ATLAS Collaboration in the pT interval 7<pT<12 GeV/c was used [74]. The published ATLAS measurement, dσ/dpT, was divided by 1/(2πpTcentreΔy), where pTcentre denotes the central values of the pT bins, and Δy the rapidity range covered by the measurement. In the overlap interval 7<pT<8 GeV/c the ALICE and ATLAS measurements, which agree within uncertainties, were combined as a weighted average. The inverse quadratic sum of statistical and systematic uncertainties of the two spectra were used as weights. Perturbative QCD (pQCD) calculations at fixed order with next-to-leading-log (FONLL) resummation [75–77] describe all aforementioned pp results [58,59] within experimental and theoretical uncertainties. The pp references are measured in a symmetric rapidity window (|ycms|<0.8 at s=2.76 TeV and |ycms|<0.5 at s=7 TeV). The effect due to the different asymmetric rapidity window in this analysis was estimated with FONLL and is much smaller than the systematic uncertainties of the data, therefore is was neglected.An assumption about the s dependence of the heavy-flavour production cross sections is required for the interpolation. Calculations based on pQCD are consistent with a power-law scaling of the heavy-flavour production cross section with s [78]. Therefore, this scaling was used to calculate the interpolated data points. The statistical uncertainties of the spectra at s=2.76 TeV and s=7 TeV were added in quadrature with weights according to the s interpolation. The weighted correlated systematic uncertainties (tracking, matching and eID) of the spectra at s=2.76 TeV and s=7 TeV were added linearly, while the weighted uncorrelated uncertainties (ITS layer conditions, unfolding and cocktail systematics) were added in quadrature. The weights were determined according to the s interpolation. The uncorrelated and correlated uncertainties were then added in quadrature.The systematic uncertainty of the bin-by-bin interpolation procedure was added in quadrature to the previous ones. It was estimated by using a linear or exponential dependence on s instead of a power law. The ratios of the resulting pT spectra to the baseline pp reference were used to estimate a systematic uncertainty of %−10+a5.The resulting pp reference cross section is well described by FONLL calculations. The systematic uncertainties of the normalisations related to the determination of the minimum-bias nucleon–nucleon cross sections of the input spectra were likewise interpolated, yielding a normalisation uncertainty of 2.3% for the pp reference spectrum, assuming that they are uncorrelated.5ResultsThe pT-differential invariant cross section of electrons from heavy-flavour hadron decays in the rapidity range −1.065<ycms<0.135 for p–Pb collisions at sNN=5.02 TeV is shown in Fig. 4 and compared with the pp reference cross section. The vertical bars represent the statistical uncertainties, while the boxes indicate the systematic uncertainties. The systematic uncertainties of the p–Pb cross section are smaller than those of the pp cross section, in particular at low transverse momentum, mainly as a consequence of the estimation of the electron background via the invariant mass technique. For the pp analysis, the background was subtracted via the cocktail method. At low pT, the electrons mainly originate from charm-hadron decays, while for pT≥4 GeV/c beauty-hadron decays are the dominant source in pp collisions [46].The nuclear modification factor RpPb of electrons from heavy-flavour hadron decays as a function of transverse momentum is shown in Fig. 5. The statistical and systematic uncertainties of the spectra in p–Pb and pp were propagated as independent uncertainties. The normalisation uncertainties of the pp reference and the p–Pb spectrum were added in quadrature and are shown as a filled box at high transverse momentum in Fig. 5.The RpPb is consistent with unity within uncertainties over the whole pT range of the measurement. The production of electrons from heavy-flavour hadron decays is thus consistent with binary collision scaling of the reference spectrum for pp collisions at the same centre-of-mass energy. The suppression of the yield of heavy-flavour production in Pb–Pb collisions at high-pT is therefore a final state effect induced by the produced hot medium.Given the large systematic uncertainties, our measurement is also compatible with an enhancement in the transverse momentum interval 1<pT<6 GeV/c as seen at mid-rapidity in d–Au collisions at sNN=200 GeV [42]. Such an enhancement might be caused by radial flow as suggested by studies on the mean pT as a function of the identified particle multiplicity [68].The data are described within the uncertainties by pQCD calculations including initial-state effects (FONLL [75] + EPS09NLO [48] nuclear shadowing parametrisation). The results suggest that initial-state effects are small at high transverse momentum in Pb–Pb collisions. Calculations by Sharma et al. which include CNM energy loss, nuclear shadowing and coherent multiple scattering at the partonic level also describe the data [27]. Calculations based on incoherent multiple scatterings by Kang et al. predict an enhancement at low pT [25]. The formation of a hydrodynamically expanding medium and consequently flow of charm and beauty quarks are expected to result in an enhancement in the nuclear modification factor RpPb [45]. To quantify the possible effect on RpPb, a blast wave calculation with parameters extracted from fits to the pT spectra of light-flavour hadrons [68] measured in p–Pb collisions was employed. The model calculation agrees with the data. However, the present uncertainties of the measurement do not allow us to discriminate among the aforementioned theoretical approaches.6Summary and conclusionsThe pT-differential invariant cross section for electrons from heavy-flavour hadron decays in minimum-bias p–Pb collisions at sNN=5.02 TeV was measured in the rapidity range −1.065<ycms<0.135 and the transverse momentum interval 0.5<pT<12 GeV/c using the combination of three electron identification methods. The application of the invariant mass technique to subtract electrons not originating from open heavy-flavour hadron decays largely reduced the systematic uncertainties with respect to the cocktail subtraction method, in particular at low transverse momentum. The pp reference for the nuclear modification factor RpPb was obtained by interpolating the measured pT-differential cross sections of electrons from heavy-flavour hadron decays at s=2.76 TeV and s=7 TeV. The RpPb is consistent with unity within uncertainties of about 25%, which become larger for pT below 1 GeV/c. The presented calculations describe the data within uncertainties. The results suggest that heavy-flavour production in minimum-bias p–Pb collisions scales with the number of binary collisions, although within uncertainties the data are also consistent with an enhancement above this scaling. The consistency with unity of the RpPb at high pT indicates that the suppression of heavy-flavour production in Pb–Pb collisions is of different origin than cold nuclear matter effects.AcknowledgementsThe ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) Collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC); Ministry of Education and Youth of the Czech Republic; Danish Natural Science Research Council, the Carlsberg Foundation and the Danish National Research Foundation; The European Research Council under the European Community's Seventh Framework Programme; Helsinki Institute of Physics and the Academy of Finland; French CNRS-IN2P3, the ‘Region Pays de Loire’, ‘Region Alsace’, ‘Region Auvergne’ and CEA, France; German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie (BMBF) and the Helmholtz Association; General Secretariat for Research and Technology, Ministry of Development, Greece; Hungarian Orszagos Tudomanyos Kutatasi Alappgrammok (OTKA) and National Office for Research and Technology (NKTH); Department of Atomic Energy and Department of Science and Technology of the Government of India; Istituto Nazionale di Fisica Nucleare (INFN) and Centro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Italy; MEXT Grant-in-Aid for Specially Promoted Research, Japan; Joint Institute for Nuclear Research, Dubna; National Research Foundation of Korea (NRF); Consejo Nacional de Cienca y Tecnologia (CONACYT), Dirección General de Asuntos del Personal Academico (DGAPA), México, Amerique Latine Formation academique – European Commission (ALFA-EC) and the EPLANET Program (European Particle Physics Latin American Network); Stichting voor Fundamenteel Onderzoek der Materie (FOM) and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; Research Council of Norway (NFR); National Science Centre, Poland; Ministry of National Education/Institute for Atomic Physics and National Council of Scientific Research in Higher Education (CNCSI-UEFISCDI), Romania; Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research; Ministry of Education of Slovakia; Department of Science and Technology, Republic of South Africa, South Africa; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America (EELA), Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellería de Educación), Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba, and IAEA (International Atomic Energy Agency); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC); The United States Department of Energy, the United States National Science Foundation, the State of Texas, and the State of Ohio; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia; Council of Scientific and Industrial Research (CSIR), New Delhi, India; Pontificia Universidad Católica del Perú.References[1]J.D.BjorkenHighly relativistic nucleus–nucleus collisions: the central rapidity regionPhys. Rev. D271983140151[2]F.KarschLattice QCD at high temperature and densityLect. Notes Phys.5832002209249arXiv:hep-lat/0106019[3]S.BorsanyiZ.FodorC.HoelblingS.D.KatzS.KriegK.K.SzaboFull result for the QCD equation of state with 2+1 flavorsPhys. Lett. B730201499104arXiv:1309.5258 [hep-lat][4]BRAHMS CollaborationI.ArseneQuark gluon plasma and color glass condensate at RHIC? The perspective from the BRAHMS experimentNucl. Phys. A7572005127arXiv:nucl-ex/0410020[5]B.B.BackThe PHOBOS perspective on discoveries at RHICNucl. Phys. A757200528101arXiv:nucl-ex/0410022[6]STAR CollaborationJ.AdamsExperimental and theoretical challenges in the search for the quark gluon plasma: the STAR collaboration's critical assessment of the evidence from RHIC collisionsNucl. Phys. A7572005102183arXiv:nucl-ex/0501009[7]PHENIX CollaborationK.AdcoxFormation of dense partonic matter in relativistic nucleus–nucleus collisions at RHIC: experimental evaluation by the PHENIX collaborationNucl. Phys. A7572005184283arXiv:nucl-ex/0410003[8]ALICE CollaborationK.AamodtCharged-particle multiplicity density at mid-rapidity in central Pb–Pb collisions at sNN=2.76 TeVPhys. Rev. Lett.1052010252301arXiv:1011.3916 [nucl-ex][9]ALICE CollaborationK.AamodtElliptic flow of charged particles in Pb–Pb collisions at 2.76 TeVPhys. Rev. Lett.1052010252302arXiv:1011.3914 [nucl-ex][10]ALICE CollaborationK.AamodtSuppression of charged particle production at large transverse momentum in central Pb–Pb collisions at sNN=2.76 TeVPhys. Lett. B69620113039arXiv:1012.1004 [nucl-ex][11]F.-M.LiuS.-X.LiuQuark-gluon plasma formation time and direct photons from heavy ion collisionsPhys. Rev. C8932014034906arXiv:1212.6587 [nucl-th][12]E.BraatenM.H.ThomaEnergy loss of a heavy fermion in a hot plasmaPhys. Rev. D44199112981310[13]R.BaierY.L.DokshitzerA.H.MuellerS.PeigneD.SchiffRadiative energy loss of high-energy quarks and gluons in a finite volume quark-gluon plasmaNucl. Phys. B4831997291320arXiv:hep-ph/9607355[14]S.WicksW.HorowitzM.DjordjevicM.GyulassyHeavy quark jet quenching with collisional plus radiative energy loss and path length fluctuationsNucl. Phys. A7832007493496arXiv:nucl-th/0701063[15]PHENIX CollaborationA.AdareEnergy loss and flow of heavy quarks in Au+Au collisions at sNN=200 GeVPhys. Rev. Lett.982007172301arXiv:nucl-ex/0611018[16]STAR CollaborationB.I.AbelevTransverse momentum and centrality dependence of high-pT non-photonic electron suppression in Au+Au collisions at sNN=200 GeVPhys. Rev. Lett.982007192301arXiv:nucl-ex/0607012STAR CollaborationB.I.AbelevTransverse momentum and centrality dependence of high-pT non-photonic electron suppression in Au+Au collisions at sNN=200 GeVPhys. Rev. Lett.1062011159902(Erratum)[17]PHENIX CollaborationA.AdareNuclear-modification factor for open-heavy-flavor production at forward rapidity in Cu+Cu collisions at sNN=200 GeVPhys. Rev. C862012024909arXiv:1204.0754 [nucl-ex][18]STAR CollaborationL.AdamczykObservation of D0 meson nuclear modifications in Au+Au collisions at sNN=200 GeVPhys. Rev. Lett.113142014142301arXiv:1404.6185 [nucl-ex][19]ALICE CollaborationB.AbelevProduction of muons from heavy flavour decays at forward rapidity in pp and Pb–Pb collisions at sNN=2.76TeVPhys. Rev. Lett.1092012112301arXiv:1205.6443 [hep-ex][20]CMS CollaborationS.ChatrchyanSuppression of non-prompt J/ψ, prompt J/ψ, and Y(1S) in PbPb collisions at sNN=2.76 TeVJ. High Energy Phys.052012063arXiv:1201.5069 [nucl-ex][21]ALICE CollaborationJ.AdamInclusive, prompt and non-prompt J/ψ production at mid-rapidity in Pb–Pb collisions at sNN=2.76 TeVJ. High Energy Phys.072015051arXiv:1504.07151 [nucl-ex][22]ALICE CollaborationJ.AdamCentrality dependence of high-pT D meson suppression in Pb–Pb collisions at sNN=2.76 TeVarXiv:1506.06604 [nucl-ex][23]N.ArmestoNuclear shadowingJ. Phys. G322006R367R394arXiv:hep-ph/0604108[24]H.FujiiF.GelisR.VenugopalanQuark pair production in high energy pA collisions: general featuresNucl. Phys. A7802006146174arXiv:hep-ph/0603099[25]Z.-B.KangI.VitevE.WangH.XingC.ZhangMultiple scattering effects on heavy meson production in p+A collisions at backward rapidityPhys. Lett. B74020152329arXiv:1409.2494 [hep-ph][26]J.W.CroninH.J.FrischM.J.ShochetJ.P.BoymondR.MermodP.A.PiroueR.L.SumnerProduction of hadrons with large transverse momentum at 200-GeV, 300-GeV, and 400-GeVPhys. Rev. D1119753105[27]R.SharmaI.VitevB.-W.ZhangLight-cone wave function approach to open heavy flavor dynamics in QCD matterPhys. Rev. C802009054902arXiv:0904.0032 [hep-ph][28]D.G.d'EnterriaHard scattering cross-sections at LHC in the Glauber approach: from pp to pA and AA collisionsarXiv:nucl-ex/0302016[29]STAR CollaborationJ.AdamsOpen charm yields in d+Au collisions at sNN=200 GeVPhys. Rev. Lett.942005062301arXiv:nucl-ex/0407006[30]PHENIX CollaborationA.Adareυ(1S+2S+3S) production in d+Au and p+p collisions at sNN=200 GeV and cold-nuclear matter effectsPhys. Rev. C872013044909arXiv:1211.4017 [nucl-ex][31]PHENIX CollaborationA.AdareTransverse-momentum dependence of the J/ψ nuclear modification in d+Au collisions at sNN=200 GeVPhys. Rev. C8732013034904arXiv:1204.0777 [nucl-ex][32]PHENIX CollaborationA.AdareNuclear modification of ψ′, χc, and J/ψ production in d+Au collisions at sNN=200 GeVPhys. Rev. Lett.111202013202301arXiv:1305.5516 [nucl-ex][33]PHENIX CollaborationA.AdareHeavy-flavor electron–muon correlations in p+p and d+Au collisions at sNN=200 GeVPhys. Rev. C8932014034915arXiv:1311.1427 [nucl-ex][34]STAR CollaborationL.AdamczykSuppression of ϒ production in d+Au and Au+Au collisions at sNN=200 GeVPhys. Lett. B7352014127137arXiv:1312.3675 [nucl-ex]STAR CollaborationL.AdamczykSuppression of ϒ production in d+Au and Au+Au collisions at sNN=200 GeVPhys. Lett. B7432015537(Erratum)[35]PHENIX CollaborationA.AdareCross section for bb¯ production via dielectrons in d+Au collisions at sNN=200 GeVPhys. Rev. C9112015014907arXiv:1405.4004 [nucl-ex][36]ALICE CollaborationB.B.AbelevSuppression of ψ(2S) production in p–Pb collisions at sNN=5.02 TeVJ. High Energy Phys.122014073arXiv:1405.3796 [nucl-ex][37]ALICE CollaborationB.B.AbelevProduction of inclusive ϒ(1S) and ϒ(2S) in p–Pb collisions at sNN=5.02 TeVPhys. Lett. B7402015105117arXiv:1410.2234 [nucl-ex][38]ALICE CollaborationJ.AdamRapidity and transverse-momentum dependence of the inclusive J/ψ nuclear modification factor in p–Pb collisions at sNN=5.02 TeVJ. High Energy Phys.062015055arXiv:1503.07179 [nucl-ex][39]ATLAS CollaborationG.AadMeasurement of differential J/ψ production cross sections and forward-backward ratios in p + Pb collisions with the ATLAS detectorPhys. Rev. C9232015034904arXiv:1505.08141 [hep-ex][40]CMS CollaborationS.ChatrchyanEvent activity dependence of Y(nS) production in sNN=5.02 TeV pPb and s=2.76 TeV pp collisionsJ. High Energy Phys.042014103arXiv:1312.6300 [nucl-ex][41]CMS CollaborationV.KhachatryanStudy of B meson production in pPb collisions at sNN=5.02 TeVarXiv:1508.06678 [nucl-ex][42]PHENIX CollaborationA.AdareCold-nuclear-matter effects on heavy-quark production in d+Au collisions at sNN=200 GeVPhys. Rev. Lett.109242012242301arXiv:1208.1293 [nucl-ex][43]PHENIX CollaborationA.AdareCold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d+Au collisions at sNN=200 GeVPhys. Rev. Lett.112252014252301arXiv:1310.1005 [nucl-ex][44]ALICE CollaborationB.B.AbelevMeasurement of prompt D-meson production in p–Pb collisions at sNN=5.02 TeVPhys. Rev. Lett.113232014232301arXiv:1405.3452 [nucl-ex][45]A.M.SicklesPossible evidence for radial flow of heavy mesons in d+Au collisionsPhys. Lett. B73120145156arXiv:1309.6924 [nucl-th][46]ALICE CollaborationB.AbelevMeasurement of electrons from beauty hadron decays in pp collisions at s=7 TeVPhys. Lett. B72120131323arXiv:1208.1902 [hep-ex][47]A.DaineseCharm production and in-medium QCD energy loss in nucleus–nucleus collisions with ALICE: a performance studyPhD thesis2003Padua U.arXiv:nucl-ex/0311004[48]K.J.EskolaH.PaukkunenC.A.SalgadoEPS09: a new generation of NLO and LO nuclear parton distribution functionsJ. High Energy Phys.042009065arXiv:0902.4154 [hep-ph][49]ALICE CollaborationK.AamodtThe ALICE experiment at the CERN LHCJ. Instrum.32008S08002[50]ALICE CollaborationB.B.AbelevPerformance of the ALICE experiment at the CERN LHCInt. J. Mod. Phys. A2920141430044arXiv:1402.4476 [nucl-ex][51]ALICE CollaborationK.AamodtAlignment of the ALICE inner tracking system with cosmic-ray tracksJ. Instrum.52010P03003arXiv:1001.0502 [physics.ins-det][52]J.AlmeThe ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity eventsNucl. Instrum. Methods A6222010316367arXiv:1001.1950 [physics.ins-det][53]ALICE Collaboration, P. Cortese, et al., ALICE: addendum to the technical design report of the time of flight system (TOF), CERN-LHCC-2002-016 (2002) (URL: https://cds.cern.ch/record/545834).[54]ALICE Collaboration, P. Cortese, et al., ALICE technical design report on forward detectors: FMD, T0 and V0, CERN-LHCC-2004-025 (2004) (URL: https://cds.cern.ch/record/781854).[55]ALICE Collaboration, P. Cortese, et al., ALICE electromagnetic calorimeter technical design report, CERN-LHCC-2008-014 (2008) (URL: https://cds.cern.ch/record/1121574).[56]ALICE CollaborationB.B.AbelevMeasurement of visible cross sections in proton-lead collisions at sNN=5.02 TeV in van der Meer scans with the ALICE detectorJ. Instrum.9112014P11003arXiv:1405.1849 [nucl-ex][57]ALICE CollaborationB.AbelevPseudorapidity density of charged particles in p–Pb collisions at sNN=5.02 TeVPhys. Rev. Lett.11032013032301arXiv:1210.3615 [nucl-ex][58]ALICE CollaborationB.B.AbelevMeasurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at s=2.76 TeVPhys. Rev. D9112015012001arXiv:1405.4117 [nucl-ex][59]ALICE CollaborationB.AbelevMeasurement of electrons from semileptonic heavy-flavour hadron decays in pp collisions at s=7 TeVPhys. Rev. D862012112007arXiv:1205.5423 [hep-ex][60]ALICE CollaborationB.AbelevNeutral pion and η meson production in proton–proton collisions at s=0.9 TeV and s=7 TeVPhys. Lett. B7172012162172arXiv:1205.5724 [hep-ex][61]ALICE CollaborationB.B.AbelevNeutral pion production at midrapidity in pp and Pb–Pb collisions at sNN=2.76 TeVEur. Phys. J. C741020143108arXiv:1405.3794 [nucl-ex][62]PHENIX CollaborationA.AdareDetailed measurement of the e+e− pair continuum in p+p and Au+Au collisions at sNN=200 GeV and implications for direct photon productionPhys. Rev. C812010034911arXiv:0912.0244 [nucl-ex][63]L.E.GordonW.VogelsangPolarized and unpolarized isolated prompt photon production beyond the leading orderPhys. Rev. D50199419011916[64]M.GyulassyX.-N.WangHIJING 1.0: a Monte Carlo program for parton and particle production in high-energy hadronic and nuclear collisionsComput. Phys. Commun.831994307arXiv:nucl-th/9502021[65]T.SjostrandS.MrennaP.Z.SkandsPYTHIA 6.4 physics and manualJ. High Energy Phys.052006026arXiv:hep-ph/0603175[66]P.Z.SkandsTuning Monte Carlo generators: the Perugia tunesPhys. Rev. D822010074018arXiv:1005.3457 [hep-ph][67]R. Brun, F. Carminati, S. Giani, GEANT detector description and simulation tool, CERN Program Library long writeup W5013 (1994).[68]ALICE CollaborationB.B.AbelevMultiplicity dependence of pion, kaon, proton and lambda production in p–Pb collisions at sNN=5.02 TeVPhys. Lett. B72820142538arXiv:1307.6796 [nucl-ex][69]ALICE CollaborationJ.AdamMultiplicity dependence of charged pion, kaon, and (anti)proton production at large transverse momentum in p–Pb collisions at sNN=5.02 TeVarXiv:1601.03658 [nucl-ex][70]G. D'Agostini, Bayesian reasoning in high-energy physics: principles and applications, CERN-YELLOW-99-03 (1999) (URL: http://cds.cern.ch/record/395902).[71]J.F.Grosse-OetringhausMeasurement of the charged-particle multiplicity in proton–proton collisions with the ALICE detectorPhD thesis2009Munster U.https://inspirehep.net/record/887184/files/CERN-THESIS-2009-033.pdf[72]F.BossuZ.C.del ValleA.de FalcoM.GagliardiS.GrigoryanG.Martinez GarciaPhenomenological interpolation of the inclusive J/psi cross section to proton–proton collisions at 2.76 TeV and 5.5 TeVarXiv:1103.2394 [nucl-ex][73]ALICE CollaborationB.B.AbelevTransverse momentum dependence of inclusive primary charged-particle production in p–Pb collisions at sNN=5.02 TeVEur. Phys. J. C74920143054arXiv:1405.2737 [nucl-ex][74]ATLAS CollaborationG.AadMeasurements of the electron and muon inclusive cross-sections in proton–proton collisions at s=7 TeV with the ATLAS detectorPhys. Lett. B7072012438458arXiv:1109.0525 [hep-ex][75]M.CacciariM.GrecoP.NasonThe P(T) spectrum in heavy flavor hadroproductionJ. High Energy Phys.051998007arXiv:hep-ph/9803400[76]M.CacciariS.FrixioneP.NasonThe p(T) spectrum in heavy flavor photoproductionJ. High Energy Phys.032001006arXiv:hep-ph/0102134[77]M.CacciariS.FrixioneN.HoudeauM.L.ManganoP.NasonG.RidolfiTheoretical predictions for charm and bottom production at the LHCJ. High Energy Phys.102012137arXiv:1205.6344 [hep-ph][78]ALICE CollaborationB.AbelevMeasurement of charm production at central rapidity in proton–proton collisions at s=2.76 TeVJ. High Energy Phys.072012191arXiv:1205.4007 [hep-ex]