Constraints on Neutrino Electric Millicharge from Experiments of Elastic Neutrino-Electron Interaction and Future Experimental Proposals Involving Coherent Elastic Neutrino-Nucleus Scattering

Abstract

In several extensions of the Standard Model of Particle Physics (SMPP), the neutrinos acquire electromagnetic properties such as the electric millicharge. Theoretical and experimental bounds have been reported in the literature for this parameter. In this work, we first carried out a statistical analysis by using data from reactor neutrino experiments, which include elastic neutrino-electron scattering (ENES) processes, in order to obtain both individual and combined limits on the neutrino electric millicharge (NEM). Then, we performed a similar calculation to show an estimate of the sensitivity of future experiments of reactor neutrinos to the NEM, by involving coherent elastic neutrino-nucleus scattering (CENNS). In the first case, the constraints achieved from the combination of several experiments are − 1.1 × 1 0 − 12 e < q ν < 9.3 × 1 0 − 13 e (90% C.L.), and in the second scenario, we obtained the bounds − 1.8 × 1 0 − 14 e < q ν < 1.8 × 1 0 − 14 e (90% C.L.). As we will show here, these combined analyses of different experimental data can lead to stronger constraints than those based on individual analysis, where CENNS interactions would stand out as an important alternative to improve the current limits on NEM.

Concept of Coherence in Neutrino and Antineutrino Scattering off Nuclei

“…Concluding this section, we stress that a new and unique result is obtained [19,20], which is demonstrated by formulas ( 125) and ( 126), (127) or ( 128), (129) and consists in "smooth" transition of the (anti)neutrino-nucleus scattering cross section from the coherent regime (129) to the incoherent regime (128).…”

“…In what follows the left and upper indices indicate neutrinos, and the right and lower indices indicate antineutrinos. In terms of , i.e., of the number of the -type nucleons with the spin projection on the direction of the incident lepton momentum, the coherent and incoherent terms from ( 125) are (126) (127) In terms of and , these terms are respectively 16 (128) (129) Recall that or , and the kinematic variables are given by the expressions Here is the total energy squared of the neutrino and nucleon, where is the four-momentum of the initial lepton, and is the effective four-momentum of the scattering nucleon that is a solution of nucleus energy-momentum conservation equation (49). The variables and are completely determined by the kinematics of the neutrino-nucleon system.…”

“…The form factors of the 127 I and 133 Cs nuclei were calculated using the effective interaction [80] and the space of states of spherical orbitals , , , , and on the basis of the filled 100 Sn core. Six internal configurations for 127 I and three for 133 Cs were considered. This was enough to adequately reproduce the most important characteristics of these isotopes.…”

“…Concluding the brief review of physical problems for CEvNS experiments, it should be mentioned that the novelty potential of the problems is high indeed. New works on this subject are regularly published (see, for example, [126][127][128][129][130][131][132][133][134][135][136]).…”

Electromagnetic neutrinos: The theory and bounds from scattering experiments

“…Only constraints (the upper bounds on neutrino electromagnetic characteristics) are obtained in different experiments. The available constraints are discussed in the review paper [1] (see also [5], [6], [7], [8] and [9] for the latest developments and progress in this field).…”