General neutrino interactions with sterile neutrinos in light of coherent neutrino-nucleus scattering and meson invisible decays

Abstract

In this work we study the current bounds from the CEνNS process and meson invisible decays on generic neutrino interactions with sterile neutrinos in effective field theories. The interactions between quarks and left-handed SM neutrinos and/or right-handed neutrinos are first described by the low-energy effective field theory (LNEFT) between the electroweak scale and the chiral symmetry breaking scale. We complete the independent operator basis for the LNEFT up to dimension-6 by including both the lepton-number-conserving (LNC) and lepton-number-violating (LNV) operators involving right-handed neutrinos. We translate the bounds on the LNEFT Wilson coefficients from the COHERENT observation and calculate the branching fractions of light meson invisible decays. The bounds on LNEFT are then mapped onto the SM effective field theory with sterile neutrinos (SMNEFT) to constrain new physics above the electroweak scale. We find that the meson invisible decays can provide the only sensitive probe for τ neutrino flavor component and s quark component in the quark-neutrino interactions involving two (one) active neutrinos and for the effective operators without any active neutrino fields. The CEνNS process places the most stringent bound on all other Wilson coefficients. By assuming one dominant Wilson coefficient at a time in SMNEFT and negligible sterile neutrino mass, the most stringent limits on the new physics scale are 2.7–10 TeV from corresponding dipole operator in LNEFT and 0.5–1.5 TeV from neutrino-quark operator in LNEFT.

Anomalous dimensions from gauge couplings in SMEFT with right-handed neutrinos

“…We briefly comment on some phenomenological consequences of our results; for earlier work see refs. [20][21][22][23][24][25]. Semileptonic decays of the b quark are topical given that both charged current and neutral current decay measurements are hinting at new physics.…”

Constraints on general neutrino interactions with exotic fermion from neutrino-electron scattering experiments

“…The survival probability of solar neutrinos is given by [ in the Borexino measurement [41]. We consider the pp, 7 Be and pep spectra measured in the Borexino phase-I [42][43][44] and phase-II [22,45], and the 8 B data collected between January 2008 and December 2016 [46]. The expected event rate at Borexino is given by…”

“…where N e = 3.307 × 10 31 /100 ton is the density of target electrons in the Borexino detector [22], and i indicates solar neutrino sources pp, 7 Be, pep and 8 B. Φ i (E ν ) is the corresponding solar neutrino flux taken from the standard solar model (B16-GS98-HZ) [47]. P i ee is the survival probability given in eq.…”

“…The couplings between the neutrinos and sub-GeV DM through the scattering off nucleus have been studied in refs. [2][3][4][5][6][7][8][9]. There are also plenty of novel models and signatures proposed to search for sub-GeV DM through the scattering off electrons [10][11][12][13][14][15].…”

Dark Matter EFT, the Third -- Neutrino WIMPs

“…For our present purposes then, our νDMEFT is equivalent to the regular DMEFT. We simply identify the fermionic singlet DM as a stable (or at least very long-lived) sterile neutrino to stress the connection to the currently actively discussed topic of Standard Model Effective Field Theory (SMEFT) extended with sterile neutrinos (νSMEFT or SMNEFT) [35,[39][40][41][42][43][44][45]. The standard seesaw mechanism as one possible origin of Majorana neutrinos N implies that other sterile neutrinos would have to be heavier, so they decouple and decay before N freezes out.…”