Cosmic neutrino spectrum and the muon anomalous magnetic moment in the gaugedLμ−Lτmodel

Abstract

The energy spectrum of cosmic neutrinos, which was recently reported by the IceCube Collaboration, shows a gap between 400 TeV and 1 PeV. An unknown neutrino interaction mediated by a field with a mass of the MeV scale is one of the possible solutions to this gap. We examine whether the leptonic gauge interaction Lh -L r can simultaneously explain the two phenomena in the lepton sector: the gap in the cosmic neutrino spectrum and the unsettled disagreement in the muon anomalous magnetic moment. We illustrate that there remain regions in the model parameter space which account for both of the problems. Our results also provide a hint to the distance to the source of the high-energy cosmic neutrinos.

Detecting the Lμ−Lτ gauge boson at Belle II

“…Differing from the search for a dark photon with a constant kinetic mixing (e.g., Ref. [67]), the signal event in the U (1) L µ −L τ model is strongly enhanced with a small M Z , with which the inconsistency in the muon anomalous magnetic moment and the gap in the IceCube spectrum can be simultaneously explained [23]. The cross section of the signal event reaches O(1) ab with the parameters g Z = 10 −3 and M Z < 1 GeV, i.e., O(10) events are expected at the Belle-II experiment with the design luminosity.…”

“…It is interesting to point out that the Z lies on the parameter region of Eq. (10), resonantly enhancing the scattering of high-energy cosmic neutrinos on the cosmic neutrino background, and the scattering can leave characteristic absorption lines in the cosmic neutrino spectrum observed at the Earth [23]. The IceCube experiment reported a gap in the cosmic neutrino spectrum between 400 TeV and 1 PeV [95], 7 and it was demonstrated in Ref.…”

“…As a theoretical framework of such a light boson, the gauged U (1) L µ −L τ model [34][35][36] has particularly gained a lot of attention, because the model is free from gauge anomaly without any extension of particle content. Moreover, recent studies reveal that the gauge boson with an MeV-scale mass, which resolves the discrepancy in muon anomalous magnetic moment, can simultaneously explain either the deficit in the highenergy cosmic neutrino spectrum [23][24][25][26] or the problem of the relic abundance of DM in the scenario with a light weakly interacting massive particle [37][38][39][40]. The L µ − L τ symmetry has been discussed also in the context of the lepton-flavor nonuniversality in B decays [41][42][43], leptonflavor-violating decay of the Higgs boson [42,44], the flavor structure of neutrino mass matrix [40,[45][46][47][48][49], and dark matter phenomenology [38,40,43,49].…”

“…In fact, extensions of the SM with a new boson possessing a mass around the MeV scale and only feebly interacting with our visible sector have been recently discussed in much literature, which is motivated by phenomenological observations. Those include the discrepancy between the SM predictions and the experimental measurements of the muon anomalous magnetic moment [8,9], inconsistency in the measurement of the e + e − pair produced in the transition between an excited state of 8 Be and its ground state [10][11][12][13][14][15], the tension between the sterile neutrino suggested by the short-baseline neutrino experiments and cosmological observations [16][17][18], the deficit of high-energy cosmic neutrino events, which is reported by the IceCube experiment [19][20][21][22][23][24][25][26][27], and the disagreement in the measurement of the proton radius [28][29][30][31]. It is also known that a light force carrier that intermediates between the DM promotes the annihilation of the DM in the early Universe and helps to reproduce the correct relic density [32,33].…”

Testing the Dark Matter Scenario for PeV Neutrinos Observed in IceCube

“…Summary and discussion.-The discovery of cosmic neutrinos opens up a new window to probe new physics beyond the Standard Model, such as neutrino selfinteractions [79,[86][87][88][89][90] and Lorentz-invariance violation [91][92][93]. The VHDM scenario has been considered as an explanation for the cosmic neutrinos.…”