Neutrino dipole portal at electron colliders

作者：Zhang, Yu; Song, Mao; Ding, Ran; Chen, Liangwen^*

来源：Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics , 2022, 829: 137116.

DOI：10.1016/j.physletb.2022.137116

• PHYSICS

We propose to search for a heavy neutral lepton (HNL), that is also known as sterile neutrino, in electron colliders running with the center-of-mass energies at few GeV, including BESIII, Belle II, and the proposed Super Tau Charm Factory (STCF). We consider the HNL interacting with Standard Model neutrino and photon via a transition magnetic moment, the so-called dipole portal. We use the monophoton signature at electron colliders to probe the constraints on the active-sterile neutrino transition magnetic moments d as the function of the HNL's mass m(N). It is found that BESIII, Belle II and STCF can probe the upper limits for d down to 1.3 x 10(-5) GeV-1, 8 x 10(-6) GeV-1, and 1.3 x 10(-6) GeV-1 with mN around GeV scale, respectively, and have sensitivity to the previously unexplored parameter space for electron-(d(e)) and tau-neutrino (d(tau)) dipole portal with m(N) from dozens to thousands MeV. On d(mu) for HNL mixing with the muon-neutrino, Belle II and STCF can also provide leading constraints.