Neutrino transition magnetic moments within the non-standard neutrino-nucleus interactions

Tensorial non-standard neutrino interactions are studied through a combined analysis of nuclear structure calculations and a sensitivity $\chi^2$-type of neutrino events expected to be measured at the COHERENT experiment, recently planned to operate at the Spallation Neutron Source (Oak Ridge). Potential sizeable predictions on transition neutrino magnetic moments and other electromagnetic parameters, such as neutrino milli-charges, are also addressed. The non-standard neutrino-nucleus processes, explored from nuclear physics perspectives within the context of quasi-particle random phase approximation, are exploited in order to estimate the expected number of events originating from vector and tensor exotic interactions for the case of reactor neutrinos, studied with TEXONO and GEMMA neutrino detectors.Comment: 7 pages, 6 Figures, 2 Tables, Accepted for publication to Physics Letters

Nuclear aspects of neutral current non-standard ν\nu-nucleus reactions and the role of the exotic μ−→e−\mu^-\to e^{-} transitions experimental limits

The nuclear aspects of flavour changing neutral current (FCNC) processes, predicted by various new-physics models to occur in the presence of nuclei, are examined by computing the relevant nuclear matrix elements within the context of the quasi-particle RPA using realistic strong two-body forces. One of our aims is to explore the role of the non-standard interactions (NSI) in the leptonic sector and specifically: (i) in lepton flavour violating (LFV) processes involving the neutral particles $\nu_\ell$ and $\tilde{\nu}_\ell$, $\ell = e,\mu,\tau$ and (ii) in charged lepton flavour violating (cLFV) processes involving the charged leptons $\ell^-$ or $\ell^+$. As concrete nuclear systems we have chosen the stopping targets of $\mu^-\rightarrow e^-$ conversion experiments, i.e. the $^{48}\mathrm{Ti}$ nucleus of the PRIME/PRISM experiment at J-PARC and the $^{27}\mathrm{Al}$ of the COMET at J-PARC as well as of the Mu2e at Fermilab. These experiments have been designed to reduce the single event sensitivity down to $10^{-16}$--$10^{-18}$ in searching for charged lepton mixing events. Our goal is, by taking advantage of our detailed nuclear structure calculations and using the present limits or the sensitivity of the aforementioned exotic $\mu^- \rightarrow e^-$ experiments, to put stringent constraints on the parameters of NSI Lagrangians.Comment: 8 pages, 4 figures, 3 Tables, Physics Letters B accepte