Z-induced FCNC's and their effects on neutrino oscillations

Abstract

Adding singlet neutrinos to the standard model spectrum in general gives rise to Z-induced flavor-changing neutral currents. We study the impact of these currents on matter-induced neutrino oscillations in the sun and in supernovae. While the effects for solar neutrinos are negligible, dramatic effects are possible for supernova neutrinos.

Probing nonstandard neutrino interactions with supernova neutrinos

“…In contrast to previous work [49][50][51], we have not restricted ourselves to large values of Y e , discussing also small values present in the inner layers. This way our generalized description includes both the possibility of neutrinos having the massless NSI-induced resonant conversions in the inner layers of the SN envelope [13,47,48], as well as the ''outer'' oscillation-induced conversions [49][50][51]56].…”

“…[52,53] they studied the corrections that such NSI would have on the expressions for the survival probabilities in the standard resonances MSW-H and MSW-L. A similar analysis was performed in Ref. [50] assuming Z-induced NSI interactions originated by additional heavy neutrinos. A phenomenological generalization of these results was carried out in Ref.…”

“…4 (color online). Contours of constant jump probability at the I-resonance in terms of " and " e for two profiles corresponding to The presence of NSI with values of j" j & 10 ÿ2 modifies the properties of the H and L transitions [49][50][51]. In particular one finds that the effects of the NSI can be described as in the standard case by embedding the "'s into effective mixing angles [51].…”

“…On the other hand several subsequent articles [49][50][51] considered the effects of NSI on the neutrino propagation in a three-neutrino mixing scenario for the case Y e > 0:4, typical for the outer SN envelope. Together with the assumption that " dV & 10 ÿ2 this prevents the appearance of internal resonances in contrast to previous references.…”

Perspectives for tests of neutrino mass generation at the GeV scale: Experimental reach versus theoretical predictions

“…The mass term Lagrangian in the seesaw mechanism is, below the EWSB scale, given by [26] − L mass ¼ 1 2 N experimental signatures of sterile neutrinos besides those already mentioned. The active-sterile mixing can modify the EW precision observables such as the Z invisible decay width, the Fermi constant G F , and other EW parameters in the SM and lead to lepton number/flavor violation (LFV) [101][102][103][104][105][106][107][108][109]. Therefore, deviations from the SM values of these observables might suggest the existence of sterile neutrinos.…”