In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs), discussing both the constraints on the magnitudes of the three transition moments Lambda_i as well as the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1 x 10^-11 mu_B at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Lambda_1| < 5.6 x10^-11 mu_B, |Lambda_2| < 4.0 x 10^-11 mu_B, and |Lambda_3| < 3.1 x 10^-11 mu_B (90% C.L.), irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, and presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.Comment: 20 pages, 4 figures, Addendum on the limit from the Borexino dat

After the first measurement of the coherent elastic neutrino nucleus scattering (CENNS) by the COHERENT Collaboration, it is expected that new experiments will confirm the observation. Such measurements will allow to put stronger constraints or discover new physics as well as to probe the Standard Model by measuring its parameters. This is the case of the weak mixing angle at low energies, which could be measured with an increased precision in future results of CENNS experiments using, for example, reactor antineutrinos. In this work we analyze the physics potential of different proposals for the improvement of our current knowledge of this observable and show that they are very promising.

Short distance reactor antineutrino experiments measure an antineutrino spectrum a few percent lower than expected from theoretical predictions. In this work we study the potential of low energy threshold reactor experiments in the context of a light sterile neutrino signal. We discuss the perspectives of the recently detected coherent elastic neutrino-nucleus scattering in future reactor antineutrino experiments. We find that the expectations to improve the current constraints on the mixing with sterile neutrinos are promising. We also analyse the measurements of antineutrino scattering off electrons from short distance reactor experiments. In this case, despite the statistics is not competitive with inverse beta decay experiments, the restrictions play an important role when we compare it with the Gallium anomaly. PACS numbers: 13.15.+g , 14.60.St I. INTRODUCTIONNeutrino physics is already in the precision physics era; with recent Nobel prize awarded in 2015 and with most of the Standard Model parameters already measured with good accuracy [1]. Future neutrino experiments will try to improve the determination of these parameters, especially the neutrino CP violating phase [2]. Besides oscillations, there is also a complete program of neutrino experiments aiming to improve the measurements of neutrino cross sections [3,4].Historically, reactor neutrino experiments have been a powerful tool in the measurement of neutrino electron scattering [5]. Recently, several experiments have measured this process with an increased precision [6-9] and it is expected that new results will be reported in the near future, for instance by the GEMMA experiment [10]. Despite the small cross section, neutrino electron scattering data have given interesting results on neutrino properties, such as neutrino magnetic moments [11], as well as on the value of the weak mixing angle at low energies [12].Regarding inverse beta decay (IBD) experiments, besides the succesful measurements of the standard oscillation parameters, both for long [13,14] and for short baselines [15][16][17], there is also a complete program to unambiguously discover or exclude sterile neutrinos in the near future. Some of these experiments are underway and others will start data taking soon [18][19][20]. Recent results from the NEOS experiment already exclude part of the previously allowed region in the most recent 3+1 sterile neutrino data fit [21]. Also in the low energy threshold regime, there is the coherent elastic neutrino nucleus scattering (CENNS), that was studied for the first time in the seventies [22] and has finally been observed [23]. A large number of proposals are also looking for this signal, and there will be several measurements of the neutrino cross sections with this reaction in the future. As it has been proved by the COHERENT Collaboration [23], CENNS is a very promising process for low energy neutrino physics. Several works have pointed out its impact in testing non-standard interactions [24][25][26][27][28][29], neutrino magnetic moment [30]...

Taking into account recent theoretical and experimental inputs on reactor fluxes we reconsider the determination of the weak mixing angle from low energy experiments. We perform a global analysis to all available neutrino-electron scattering data from reactor antineutrino experiments, obtaining sin 2 θW = 0.252 ± 0.030. We discuss the impact of the new theoretical prediction for the neutrino spectrum, the new measurement of the reactor antineutrino spectrum by the Daya Bay collaboration, as well as the effect of radiative corrections. We also reanalyze the measurements of the νe − e cross section at accelerator experiments including radiative corrections. By combining reactor and accelerator data we obtain an improved determination for the weak mixing angle, sin 2 θW = 0.254 ± 0.024.