Search

Neutrino magnetic moment ($\nu$MM) is an important property of massive neutrinos. The recent anomalous excess at few keV electronic recoils observed by the Xenon1T collaboration might indicate a $\sim 2.2\times10^{-11} \mu_B$ effective neutrino magnetic moment ($\mu_\nu^{eff}$) from solar neutrinos. Therefore, it is essential to carry out the $\nu$MM searches at a different experiment to confirm or exclude such hypothesis. We study the feasibility of doing $\nu$MM measurement with 4 kton active mass at Jinping neutrino experiment using electron recoil data from both natural and artificial neutrino sources. The sensitivity of $\mu_\nu^{eff}$ can reach $1.2\times10^{-11}\mu_B$ at 90\% C.L. with 10-year data taking of solar neutrinos. Besides the intrinsic low energy background $^{14}$C in the liquid scintillator, we find the sensitivity to $\nu$MM is highly correlated with the systematic uncertainties of $pp$ and $^{85}$Kr. Reducing systematic uncertainties ($pp$ and $^{85}$Kr) and the intrinsic background ($^{14}$C and $^{85}$Kr) can help to improve sensitivities below these levels and reach the region of astrophysical interest. With a 3 mega-Curie (MCi) artificial neutrino source $^{51}$Cr installed at Jinping neutrino detector for 55 days, it could give us a sensitivity to the electron neutrino magnetic moment ($\mu_{\nu_e}$) with $1.1\times10^{-11} \mu_B$ at 90\% C.L.. With the combination of those two measurements, the flavor structure of the neutrino magnetic moment can be also probed at Jinping., Comment: 18 pages, 9 figures

The study of very low energy neutrinos requires a suppression of the natural radioactivity up to ultra-traces level. This is what the Borexino experiment succeeded to achieve with the development of technologies for liquid purification and non-standard approaches in constructing and assembling the detector, allowing a threshold down to 50 keV. Thanks to these measures, the entire solar neutrino spectrum has been detected, neglecting the hep neutrinos which account for less than 10 − 5 of the total flux, together with a small, but clean and robust geoneutrino signal; they represent new achievements in the physics of the Sun, the stars and neutrinos, and they open new horizons in the study of the Earth’s interior too. This report describes the technology employed to achieve these goals and the results obtained throughout more than 10 years of data collection. Among the results, actual breakthroughs can be counted: the identification of the nuclear reactions which produce 99% of solar energy and consequently solar luminosity, combined with the demonstration of the solar stability on a 105 years scale; the confirmation of the Standard Solar Model predictions through the measured neutrino fluxes, leading the way for a significant indication in favor of the high metallicity composition of the Sun; the independent demonstration of the validity of the MSW neutrino oscillation solution, through the determination in a single experiment of the distinctive transition of the electron neutrino survival probability from the matter to the vacuum regime; and finally the achievement of the first experimental evidence of the CNO cycle, which dominates in the stars. To this date BOREXINO is a unique experiment with its unprecedented radiopurity level, achieved by means of innovative techniques, which have now become a standard reference for the whole physics field of rare events search.

Neutrino can carry information from places that cannot be reached by the usual detection mechanism because it has a very weak interaction with matter. This can be utilized to study the heat flow process inside the earth by using information carried by geoneutrino (electron antineutrino). In this sense, it is important to know the characteristics of neutrino interaction with materials. In this study, the cross-section calculation of the electron antineutrino interaction with Ar-40 and Kr-84 was carried out using computational methods with the help of GENIE software. In the energy range of 0-10 MeV, the dominant interaction between the two materials is the interaction of QES NC and MEC types with an energy threshold of 5,09 MeV. Both Ar-40 and Kr-84 cannot be used as a scintillator material for geoneutrino detection because in the energy range 0-4,4 MeV the cross-sectional value of the CC interaction is 0.

The left-right symmetric model may present evidence of new physics at the era of the Large Hadron Collider (LHC). We use its framework to investigate the lepton number violating process $pp \to e^\pm e^\pm jj+X$ at the $\unit[14]{TeV}$ LHC. We show that for an integrated luminosity of $\unit[300]{fb^{-1}}$, the discovery contour of the right-handed boson $W_R$ and the right-handed electron neutrino $N_e$ as a result of the $pp \to W^\pm_R \to e^\pm N \to e^\pm e^\pm jj$ process can be expanded upon considering an additional channel mediated by the right-handed doubly charged Higgs $\delta^{\pm\pm}_R$, i.e. $pp\to W^\pm_R \to W^{\mp*}_R \delta^{\pm\pm*}_R \to e^\pm e^\pm jj$., Comment: 28 pages, 7 figures, 2 tables

After gravitational wave (GW) transients were first observed in 2015, searching for the coincident neutrinos has become one of the most important missions at the current neutrino experiments. Particularly, the coincident searches draw more and more attentions after one GW candidate (denoted GW170817) was detected, which was the first sign of a production of a binary neutron star (BNS) merger. However, no candidate neutrinos have been found yet. As a prospective study, this article presents a search for the potential electron antineutrinos ( ν ¯ e ) from BNS mergers in future medium-baseline reactor neutrino oscillation (MBRO) experiment(s). On one hand, we examine the detection sensitivity to the ν ¯ e signals from BNS mergers at future MBRO experiment(s). On the other hand, we convert the ν ¯ e signal sensitivity to the ν ¯ e fluence upper limits and evaluate the furthest detectable distances for BNS mergers based on the evolution models describing the process of neutrino emission. Moreover, we also analyze the improvement of sensitivity and the enhancement of detectable distance with a proposed extra detector at future MBRO experiment(s).

Graphical dependencies are presented of the probability of electron neutrino preservation in a model with three active and three sterile neutrinos as a function of the neutrino distance from the source at energies, which neutrinos acquire in processes with the participation of 51Cr, 37Ar, and 65Zn nuclei. Refined values of the cross section of the reaction for neutrino capture by 71Ga nuclei are also given for interpretation and prediction of the results of experiments to verify the Gallium anomaly.

The Reactor Experiment for Neutrino Oscillation (RENO) experiment has been taking data using two identical liquid scintillator detectors of 44.5 tons since August 2011. The experiment has observed the disappearance of reactor neutrinos in their interactions with free protons, followed by neutron capture on hydrogen. Based on 1500 live days of data taken with 16.8 GW$_{th}$ reactors at the Hanbit Nuclear Power Plant in Korea, the near (far) detector observes 567690 (90747) electron antineutrino candidate events with a delayed neutron capture on hydrogen. This provides an independent measurement of $\theta_{13}$ and a consistency check on the validity of the result from n-Gd data. Furthermore, it provides an important cross-check on the systematic uncertainties of the n-Gd measurement. Based on a rate-only analysis, we obtain sin$^{2}$2$\theta _{13}$= 0.087 $\pm$ 0.008 (stat.) $\pm$ 0.014 (syst.)., Comment: 26 pages, 19 figures, 6 tables

Neutrinos are one of the most promising messengers for signals of new physics Beyond the Standard Model (BSM). On the theoretical side, their elusive nature, combined with their unknown mass mechanism, seems to indicate that the neutrino sector is indeed opening a window to new physics. On the experimental side, several long-standing anomalies have been reported in the past decades, providing a strong motivation to thoroughly test the standard three-neutrino oscillation paradigm. In this Snowmass21 white paper, we explore the potential of current and future neutrino experiments to explore BSM effects on neutrino flavor during the next decade., CAA is supported by the Faculty of Arts and Sciences of Harvard University, and the Alfred P. Sloan Foundation. GB acknowledges support from AEI-MICINN PID2020-113334GBI00 / AEI / 10.13039/501100011033. MB is supported by the Villum Fonden under project no. 29388. PC acknowledges support by Grants CEX2020-001007-S, PID2019-108892RB-I00 and RYC2018- 024240-I funded byMCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”. YF has received financial support from Saramadan under contract No. ISEF/M/400279 and No. ISEF/M/99169. TK acknowledges the support from the Science and Technology Council Facilities, UK. AMS acknowledges the support of US National Science Foundation (Grant No. PHY-2020275). This project has received funding/support from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 860881-HIDDeN. This white paper has been prepared in the context of the Snowmass’21 Community Planning exercise, as part of the activities coordinated by the NF03 subtopical group (neutrinos and BSM). It summarizes present and future opportunities to search for effects due to new physics in neutrino flavour conversion. Coordinated by Coloma, Forero and Katori. The white paper has two main parts, theoretical aspects and experimental overview and prospects. Sections are led by a wide set of researchers. On the theoretical side, we discuss the new physics in the additional neutrino states (Fernández Martínez, Forero), new interactions (Coloma, Farzan, Tabrizi), neutrino decay (Bustamante, Denton, Gago), and fundamental physics principles (Barenboim, Katori, Lehnert). On the experimental side, discussions go to different neutrino energy scales, from below GeVs (Esteban, Suliga), GeV to TeV scales (Forero, Ross-Lonergan), and beyond TeVs (Argüelles, Katori).

The problem of internal ionization in the beta decay of tritium due to the scattering of a β electron off a bound electron is discussed. The total probability of the process per a single decay event is calculated. The distributions over the momentum and the kinetic energy of a liberated electron are plotted. A correction to the β spectrum produced by internal ionization is determined. The identity of electrons is taken into account in all calculations. The results of calculations of the modified spectrum are of interest for the KATRIN experiment aimed at measuring the mass of an electron antineutrino. The high-luminosity source also makes it possible to search for keV-scale sterile neutrinos in the middle part of the β spectrum, where the internal ionization effect is significant.