A sterile neutrino at GeV mass scale is of particular interest in this work. Though not take part in neutrino oscillation, the sterile neutrino can induce flavor violating semileptonic and leptonic decay of $K, D$ and $B$ mesons. We calculated a box diagram contribution in these processes. By making use of current experiment limit of lepton flavor violating decays $M^+_h\to M_l^+\ell_1^+\ell_2^-$ and $M^0\to \ell_1^-\ell_2^+$, we explore the allowed parameter space of $U_{e4}$ and $U_{μ4}$ in different mass ranges. Generally speaking, both channels give a limit to the product of $U_{e4}$ and $U_{μ4}$. When sterile neutrino mass is located in between pion and kaon mass, $K^+\to π^+ e^{\pm}μ^{\mp}$ gives the strongest constraint while $B^+\to π^+ e^{\pm} μ^{\mp}$ provides the dominated constraint when its mass in between of kaon and B meson. If sterile neutrino is even heavier than B mesons, the $B^0_s\to μ^{\pm} e^{\mp}$ experiment which is performed at LHCb gives the strongest constraint.
We investigate lepton-number-violating decays $K^\mp \rightarrow π^\pm l^\mp l^\mp$ in the presence of sterile neutrinos. We consider minimal interactions with Standard-Model fields through Yukawa couplings as well as higher-dimensional operators in the framework of the neutrino-extended Standard Model Effective Field Theory. We use $SU(3)$ chiral perturbation theory to match to mesonic interactions and compute the lepton-number-violating decay rate in terms of the neutrino masses and the Wilson coefficients of higher-dimensional operators. For neutrinos that can be produced on-shell, the deca…
In the presence of transition magnetic moments between active and sterile neutrinos, the search for a Primakoff upscattering process at coherent elastic neutrino-nucleus scattering (CE$ν$NS) experiments can provide stringent constraints on the neutrino magnetic moment. We show that a radiative upscattering process with an emitted photon in the final state can induce a novel coincidence signal at CE$ν$NS experiments that can also probe neutrino transition magnetic moments beyond existing limits. Furthermore, the differential distributions for such a radiative mode can also potentially be sensit…
In this work, prospects to probe an overlooked facet of axion-like particles (ALPs) -- their potential couplings to sterile neutrinos -- are presented. We found that mono-photon searches have the potential to constrain ALP couplings to sterile neutrinos when a new heavy scalar boosts the ALP decay yields. Working within an effective field theory (EFT) approach, we scan the parameters space to establish the reach of the 13 TeV LHC to probe such couplings. We found regions of the parameters space evading several experimental constraints that can be probed at the LHC. Moreover, a complementary ro…
Ultraviolet Flavor Transmission to T-Violating Neutrino Oscillation Observables in a Seesaw Framework with Sterile Mixing and Planck-Suppressed Corrections
Department of Physics, Kirori Mal College, University of Delhi（德里大学科里尔马尔学院物理系）；Department of Physics, Chaudhary Charan Singh University（乔杜里·查兰·辛格大学物理系）
We present, how a systematic study of $B \to D\ell N$ ($D \to K \ell N$) decays with $\ell=μ,τ$, at Belle II (BESIII) can provide unambiguous signature of a heavy neutrino $N$ and/or constrain its mixing with active neutrinos $ν_\ell$, which is parameterized by $|U_{\ell N}|^2$. Our constraint on $|U_{μN}|^2$ that can be achieved from the full Belle II data is comparable with what can be obtained from the much larger data set of the upgraded LHCb. Additionally, our method offers better constraint on $|U_{μN}|^2$ for mass of sterile neutrino $m_N < 2$ GeV. We can also probe the Dirac and Majora…
Motivated by the first observation of coherent-elastic neutrino-nucleus scattering at the COHERENT experiment, we confront the neutrino dipole portal giving rise to the transition of the standard model neutrinos to sterile neutrinos with the recently released CENNS 10 data from the liquid argon as well as the CsI data of the COHERENT experiment. Performing statistical analysis of those data, we show how the transition magnetic moment can be constrained for the range of the sterile neutrino mass between 10 keV and 40 MeV.
While three flavors of "active" neutrinos are consistent with mixing angle results within error bars, there are anomalies may be hints of physics beyond the standard model that can accommodate a fourth mostly "sterile" neutrino species with an eV-scale mass and a mixing angle with active neutrinos of order $θ_0\simeq 0.1$. We describe a scenario with eV-scale sterile neutrinos that have self-interactions via a new gauge vector boson, a "secret" mediator $ϕ$. We show that their production in the early Universe via mixing with active neutrinos is consistent with Big Bang Nucleosynthesis and free…
