18787 2204.03011 10.1007/JHEP07(2022)138 138 138 10.1007/JHEP11(2022)138 Constraining new physics with Borexino Phase-II spectral data JHEP 25TH ANNIVERSARY SPECIAL ISSUE JHEP ANNIVERSARY SPECIAL ISSUE 1 35 2022 7 22 2022 4 20 2022 5 15 2022 7 22 2022 11 23 An Erratum to this paper has been published: https://doi.org/10.1007/JHEP11(2022)138 The Author(s) 2022 Open Access. This article is distributed under the terms of the Creative Commons Attribution License ( CC-BY 4.0 ), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited. 13130 2022 2022 7 7 Pilar Coloma pilar.coloma@ift.csic.es M. C. Gonzalez-Garcia maria.gonzalez-garcia@stonybrook.edu Michele Maltoni michele.maltoni@csic.es João Paulo Pinheiro joaopaulo.pinheiro@fqa.ub.edu Salvador Urrea salvador.urrea@ific.uv.es grid.501798.2 0000 0004 0561 6576 Instituto de Física Teórica (IFT-CFTMAT), CSIC-UAM Calle de Nicolás Cabrera 13–15, Campus de Cantoblanco E-28049 Madrid Spain grid.36425.36 0000 0001 2216 9681 C.N. Yang Institute for Theoretical Physics Stony Brook University Stony Brook NY 11794-3840 USA grid.5841.8 0000 0004 1937 0247 Departament de Física Quàntica i Astrofísica and Institut de Ciències del Cosmos Universitat de Barcelona Diagonal 647 E-08028 Barcelona Spain grid.425902.8 0000 0000 9601 989X Institució Catalana de Recerca i Estudis Avançats (ICREA) Pg. Lluis Companys 23 E-08010 Barcelona Spain grid.470047.0 0000 0001 2178 9889 Instituto de Física Corpuscular (IFIC), CSIC-UV Edificio Institutos de Investigación, Calle Catedrático José Beltrán 2 E-46980 Paterna Spain Abstract We present a detailed analysis of the spectral data of Borexino Phase II, with the aim of exploiting its full potential to constrain scenarios beyond the Standard Model. In particular, we quantify the constraints imposed on neutrino magnetic moments, neutrino non-standard interactions, and several simplified models with light scalar, pseudoscalar or vector mediators. Our analysis shows perfect agreement with those performed by the collaboration on neutrino magnetic moments and neutrino non-standard interactions in the same restricted cases and expands beyond those, stressing the interplay between flavour oscillations and flavour non-diagonal interaction effects for the correct evaluation of the event rates. For simplified models with light mediators we show the power of the spectral data to obtain robust limits beyond those previously estimated in the literature. Keywords Neutrino Interactions Non-Standard Neutrino Properties ArXiv ePrint: 2204.03011 An erratum to this article is available online at https://doi.org/10.1007/JHEP11(2022)138 .