本文从模型无关的角度探讨了用中微子探测器直接探测轻费米子暗物质的可能性。我们考虑所有的运营商的6维或更低，可以有助于相互作用$\bar{f} p \to e^+ n$，其中$f$是一个黑暗的马约拉纳或狄拉克费米子。然后从产生可见$γ$射线或电子的$f$寿命及其衰变中获得对这些算子的约束。我们发现一个算子，它将允许$\bar{f} p \to e^+ n$在有趣的速度在中微子探测器，只要$m_f \lesssim m_π$。现有的限制轻暗物质的遗迹密度参数，超新星冷却率，大爆炸核合成。我们计算了该算符所隐含的中微子探测器中的$\bar{f} p \to e^+ n$的截面，发现Super-K可以探测到该相互作用的新物理标度$Λ$直到${\cal O}(100 {TeV})$
英文摘要：
The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction $\bar{f} p \to e^+ n$, where $f$ is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the $f$ lifetime and its decays which produce visible $γ$ rays or electrons. We find one operator which would allow $\bar{f} p \to e^+ n$ at interesting rates in neutrino detectors, as long as $m_f \lesssim m_π$. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross-section for $\bar{f} p \to e^+ n$ in neutrino detectors implied by this operator, and find that Super-K can probe the new physics scale $Λ$ for this interaction up to ${\cal O}(100 {TeV})$
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We propose two-loop neutrino mass model with gauged hidden $U(1)$ symmetry, and discuss a Majorana type of dark matter candidate that has semi-annihilation processes in the relic density as well as lepton flavor violations and muon anomalous magnetic moment. Also, we demonstrate global analysis to satisfy neutrino oscillation data, lepton flavor violations, and relic density of dark matter candidate and show that semi-annihilation modes play a crucial role in finding observed relic density.
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We propose a radiative seesaw model with a hidden $U(1)$ gauge symmetry. In order to have anomaly cancellations, we need to introduce several new fermions that contribute to muon anomalous magnetic dipole moment $(g-2)_μ$ as well as explain the neutrino oscillation data. We also consider a fermionic dark matter candidate that correlates with $(g-2)_μ$ and neutrino mass matrix at the same time. We show allowed regions in our input parameters satisfying several constraints. Finally, we also briefly discuss the possibility of the resolution of the Hubble tension via neutrino self-interactions med…
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The existence of light sterile neutrinos, as predicted in several models, can help to explain a number of observations starting from dark mater to recent anomalies in short baseline experiments. In this paper we consider two models - Left-Right Symmetric Zee model and Extended Seesaw model, that can naturally accommodate the presence of light sterile neutrinos in the eV to MeV mass scale. We perform a detailed study on the neutrinoless double beta decay process which receives major contributions from diagrams involving these light sterile neutrinos. Considering a number of theoretical and expe…
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Light gauge bosons can lead to resonant interactions between high-energy astrophysical neutrinos and the cosmic neutrino background. We study this possibility in detail, considering the ability of IceCube to probe such scenarios. We find the most dramatic effects in models with a very light $Z'$ ($m_{Z'} \lesssim 10$ MeV), which can induce a significant absorption feature at $E_ν \sim\,$5-10$\,{\rm TeV} \times (m_{Z'}/{\rm MeV})^2$. In the case of the inverted hierarchy and a small sum of neutrino masses, such a light $Z'$ can result in a broad and deep spectral feature at $\sim\,$0.1-10$\,{\r…
Evidence was previously reported for an 8 MeV neutrino line associated with SN 1987A based on an analysis of 997 events recorded in the Kamiokande-II detector on the day of the supernova. That claimed line, however, occurred at the peak of the background spectrum, and both had a similar shape, making the claim tenuous at best. Here the claim is buttressed by providing five reasons to expect such an 8 MeV neutrino line. A final section of the paper concerns the ongoing KATRIN experiment to find the neutrino mass, which might provide additional support for the line, should it validate a controve…
Sterile neutrinos at the GeV scale can resolve several outstanding problems of the Standard Model (SM), such as the source of neutrino masses and the origin of the baryon asymmetry through freeze-in leptogenesis, but they can be challenging to detect experimentally due to their small couplings to SM particles. In extensions of the SM with new interactions of the sterile neutrinos, they can be produced copiously at accelerators and colliders. We systematically investigate the impact of such novel interactions on the asymmetry from freeze-in leptogenesis. We find that the interactions tend to br…
We report on the first results from a new dish antenna search for hidden photon dark matter (HPDM) in the meV mass region. A double mirror system composed of a plane and a parabolic mirror is designed to convert HPDMs into photons focused on a receiver. In this phase 1 experiment we obtain an upper limit on the photon-HP kinetic mixing $χ\lesssim 10^{-8}$ for the mass range of $0.67-0.92\,{\rm meV}$ using conventional mm-wave technology with a room-temperature receiver and a small-sized mirror system.
In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario that scotogenic neutrino and flavored mediator share the same inert Higgs doublet and all are charged under a hidden gauged $U(1)$ symmetry. The dark Z2 symmetry in dark sector is regarded as the remnant of this hidden $U(1)$ symmetry breaking. In particular, we investigate a dark $U(1)_D$ (and also a $U(1)_{B-L}$) model which unifies scotogenic neutrino and top-flavored mediator. In this model dark tops and dark n…
We propose a neutrinophilic two Higgs doublet model with hidden local $U(1)$ symmetry, where active neutrinos are Dirac type, and a fermionic DM candidate is naturally induced as a result of remnant symmetry even after the spontaneous symmetry breaking. In addition, a physical Goldstone boson is arisen as a consequence of two types of gauge singlet bosons and contributes to the DM phenomenologies as well as additional neutral gauge boson. Then we will analyze the relic density of DM within the safe range of direct detection searches, and show the allowed region of dark matter mass.
We first discuss and determine the isospin mixing of the two $2^-$ states (12.53 MeV and 12.97 MeV) of $^{16}$O nucleus using the inelastic electron scattering data. We then evaluate the cross section of 4.4-MeV $γ$ rays produced in the neutrino neutral-current (NC) reaction $^{16}$O($ν, ν^{\prime}$)$^{16}$O$(12.97 {\rm MeV}, 2^-$) in a water Cherenkov detector at the low energy below 100 MeV. The detection of $γ$ rays for $E_γ>5$ MeV from the NC reaction $^{16}$O($ν, ν^{\prime}$)$^{16}$O$(E_x>16\ {\rm MeV}, T=1$) with a water Cherenkov detector in the supernova neutrino bursts has been propos…
Recent results from neutrino experiments show evidence for light sterile neutrinos which do not have any Standard Model interactions. In this work we study the hidden interaction of sterile neutrinos with an "MeV scale" gauge boson (the $ν_s$HI model) with mass $M_X$ and leptonic coupling $g^\prime_l$. By performing an analysis on the $ν_s$HI model using the data of the MINOS neutrino experiment we find that the values above $G_X/G_F=92.4$ are excluded by more than $2σ$ C.L., where $G_F$ is the Fermi constant and $G_X$ is the field strength of the $ν_s$HI model. Using this model we can also pr…
New light species can contribute to the number of effective relativistic degrees of freedom ($N_{\rm eff}$) at Cosmic Microwave Background (CMB) which is precisely measured by Planck. In this work, we consider an MeV scale thermally decoupled non-minimal dark sector and study the imprint of the dark sector dynamics on the measurement of $N_{\rm eff}$ at the time of CMB formation. We have predicted the allowed region of model parameter space in the light of constraints arising from the measurements of both $N_{\rm eff}$ and dark matter relic density by Planck. It turns out that the impact of th…
An analysis of sub-MeV dark photon as dark matter is given which is achieved with two hidden sectors, one of which interacts directly with the visible sector while the second has only indirect coupling with the visible sector. The formalism for the evolution of three bath temperatures for the visible sector and the two hidden sectors is developed and utilized in solution of Boltzmann equations coupling the three sectors. We present exclusion plots where the sub-MeV dark photon can be dark matter. The analysis can be extended to a multi-temperature universe with multiple hidden sectors and mult…
In the near future, the neutrinoless double-beta ($0νββ$) decay experiments will hopefully reach the sensitivity of a few ${\rm meV}$ to the effective neutrino mass $|m^{}_{ββ}|$. In this paper, we tentatively examine the sensitivity of future $0νββ$-decay experiments to neutrino masses and Majorana CP phases by following the Bayesian statistical approach. Provided experimental setups corresponding to the sensitivity of $|m^{}_{ββ}| \simeq 1~{\rm meV}$, the null observation of $0νββ$ decays in the case of normal neutrino mass ordering leads to a very competitive bound on the lightest neutrino …
