${\nu }_{\mu }$ and ${\nu }_{\tau }$ elastic scattering in Borexino

Journal Article · Thu Dec 05 23:00:00 EST 2024 · Physical Review. D.

DOI:https://doi.org/10.1103/PhysRevD.110.113004· OSTI ID:2480370

Kelly, Kevin J.; Mishra, Nityasa; Rai, Mudit; Strigari, Louis E.

We perform a detailed study of neutrino-electron elastic scattering using the monoenergetic ${}^7\mathrm{Be}$ neutrinos in Borexino, with an emphasis on exploring the differences between the contributions of ${\nu }_e$ , ${\nu }_{\mu }$ , and ${\nu }_{\tau }$ . We find that current data are capable of measuring these components such that the contributions from ${\nu }_{\mu }$ and ${\nu }_{\tau }$ cannot be zero, although distinguishing between them is challenging—the differences stemming from Standard Model radiative corrections are insufficient without significantly more precise measurements. In studying these components, we compare predicted neutrino-electron scattering event rates within the Standard Model (accounting for neutrino oscillations), as well as going beyond the Standard Model in two ways. We allow for nonunitary evolution to modify neutrino oscillations, and find that with a larger exposure ( $\sim 30\mathrm{x}$ ), Borexino may provide relevant information for constraining nonunitarity, and that JUNO may be able to accomplish this with its data collection of ${}^7\mathrm{Be}$ neutrinos. We also consider novel ${\nu }_{\mu }$ - and ${\nu }_{\tau }$ -electron scattering from a gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ model, showing consistency with previous analyses of Borexino and this scenario, but also demonstrating the impact of uncertainties on Standard Model mixing parameters on these results.

Published by the American Physical Society 2024

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0010813
• OSTI ID: 2480370
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 11 Vol. 110; ISSN PRVDAQ; ISSN 2470-0010
• Publisher: American Physical Society
• Country of Publication: United States
• Language: English