Given an accelerator-based neutrino experiment with the beam energy E \lesssim 1 GeV, we expand the probabilities of ν_μ\to ν_e and \overline ν_μ\to \overline ν_e oscillations in matter in terms of two small quantities Δ_{21}/Δ_{31} and A/Δ_{31}, where Δ_{21} \equiv m^2_2 - m^2_1 and Δ_{31} \equiv m^2_3 - m^2_1 are the neutrino mass-squared differences, and A measures the strength of terrestrial matter effects. Our analytical approximations are numerically more accurate than those made by Freund in this energy region, and thus they are particularly applicable for the study of leptonic CP violation in the low-energy MOMENT, ESS\nuSM and T2K oscillation experiments. As a by-product, the new analytical approximations help us to easily understand why the matter-corrected Jarlskog parameter \widetilde{\cal J} peaks at the resonance energy E_* \simeq 0.14 GeV (or 0.12 GeV) for the normal (or inverted) neutrino mass hierarchy, and how the three Dirac unitarity triangles are deformed due to the terrestrial matter contamination. We also affirm that a medium-baseline neutrino oscillation experiment with the beam energy E lying in the E_* \lesssim E \lesssim 2 E_* range is capable of exploring leptonic CP violation with little matter-induced suppression.
The possible existence of light and heavy sterile neutrinos may give rise to direct and indirect unitarity violation of the $3\times3$ lepton mixing matrix respectively. In the current work we study the potential of future accelerator neutrino facilities in probing the unitarity violation effects. Taking DUNE, T2HK and a low-energy Neutrino Factory (LENF) as working examples of future accelerator neutrino facilities, we study the distinct effects of direct and indirect unitarity violation on the discovery reach of the leptonic CP violation and precision measurements of $θ_{23}$ in the three ne…
We investigate prospects of building a future accelerator-based neutrino oscillation experiment in China, including site selection, beam optimization and tau neutrino physics aspects. CP violation, non-unitary mixing and non-standard neutrino interactions are discussed. We simulate neutrino beam setups based on muon and beta decay techniques and compare Chinese laboratory sites by their expected sensitivities. A case study on Super Proton-Proton Collider and China JinPing Laboratory is also presented. It is shown that the muon-decay-based beam setup can measure the Dirac CP phase by about 14.2…
Searches for lepton flavor violation in tau decays are unambiguous signatures of new physics. The branching ratios of tau leptons at the level of 10^-10 - 10^-9 can be probed with 50 ab^-1 of electron-positron annihilation data being collected by the Belle II experiment at the world's highest luminosity accelerator, the SuperKEKB, located at the High Energy Accelerator Research Organization, KEK, in Tsukuba, Japan. Searches with such expected sensitivity will either discover new physics or strongly constrain several new physics models.
In this paper, we have analysed the latest data from NO$ν$A and T2K with the Lorentz invariance violation along with the standard oscillation hypothesis. We have found that the NO$ν$A data cannot distinguish between the two hypotheses at $1\, σ$ confidence level. T2K data and the combined data analysis excluded standard oscillation at $1\, σ$. All three cases do not have any hierarchy sensitivity when analysed with LIV. There is a mild tension between the two experiments, when analysed with LIV, as $θ_{23}$ at \nova best-fit is at higher octant but the same for T2K is at lower octant. NO$ν$A h…
We propose a phenomenological model of Dirac neutrino mass operator based on the Fridberg-Lee (FL) neutrino mass model to include CP violation. By considering the most general set of complex coefficients, and imposing the condition that the mass eigenvalues are real, we find a neutrino mass matrix which is non-hermitian, symmetric and magic. In particular, we find that the requirement of obtaining real mass eigenvalues by transferring the residual phases to the mass eigenstates self-consistently, dictates the following relationship between the imaginary part of the mass matrix elements $B$ and…
CP-violation or Nuclear Excitation: Reviewing the Role of Neutrino Interaction Model Uncertainties on Accelerator-Based Neutrino Oscillation Measurements
One of the fundamental parameters entering neutrino oscillation framework is the leptonic CP phase $δ_{13}$ and its measurement is an important goal of the planned long baseline experiments. It should be noted that ordinary matter effects complicate the determination of this parameter and there are studies in literature that deal with separation of intrinsic versus extrinsic CP violation. It is important to investigate the consequences of new physics effects that can not only hamper the measurement of $δ_{13}$, but also impact the consequences of discrete symmetries such as CP, T and unitarity…
Using $Δχ^2$ which is defined by the difference of the number of events with the CP phase $δ$ and the hypothetical one with $δ=0$, we discuss correlations of errors of the CP phase and other oscillation parameters as well as the matter effect in measurements at neutrino factories. By varying the oscillation parameters and the normalization of the matter effect, we evaluated the data size required to reject a hypothesis with $δ=0$ at 3$σ$CL. The optimum muon energy and the baseline depends on the magnitude of $θ_{13}$, the background fraction, the uncertainty of the normalization of the matter …
After reviewing the general framework to study EPR-like neutrino oscillations, we derive expressions for the oscillation probabilities and a direct measure of CP violation. We compare the possibility of studying CP violation in this case with that of baseline accelerator experiments and conclude that it is possible to study CP violation in experiments with length scales comparable to that of short baseline accelerator experiments.
The visible universe - it is the universe of nucleons and electrons. The appearance of nucleon mass is caused by the violation of chiral symmetry in quantum chromodynamics (QCD). For this reason, the experiments on high energy accelerators cannot shed light on the origin of the matter in the visible universe. The origin of the mass of matter will be clarified, when the mechanism of chiral symmetry violation in QCD will be elucidated.
Very soon a new generation of reactor and accelerator neutrino oscillation experiments - Double Chooz, Daya Bay, Reno and T2K - will seek for oscillation signals generated by the mixing parameter theta_13. The knowledge of this angle is a fundamental milestone to optimize further experiments aimed at detecting CP violation in the neutrino sector. Leptonic CP violation is a key phenomenon that has profound implications in particle physics and cosmology but it is clearly out of reach for the aforementioned experiments. Since late 90's, a world-wide activity is in progress to design facilities th…
We compute the neutralino decay rate in the minimal supersymmetric standard model with the addition of explicit R-parity violation. We include the complete squark and slepton mixing matrices, previously neglected, and we improve and correct published formulas. These decays are relevant to accelerator and non-accelerator searches for R-parity violation, and are especially interesting in light of the reported high Q^2 anomaly at HERA.
Motivated by experimental indications of a significant presence of heavy nuclei in the cosmic ray flux at ultra high energies ($\gtrsim 10^{19} \eV$), we consider the effects of Planck scale suppressed Lorentz Invariance Violation (LIV) on the propagation of cosmic ray nuclei. In particular we focus on LIV effects on the photodisintegration of nuclei onto the background radiation fields. After a general discussion of the behavior of the relevant quantities, we apply our formalism to a simplified model where the LIV parameters of the various nuclei are assumed to kinematically result from a sin…
Contribution of the strong CP angle, $\barθ$, to the Wilson Coefficients of electron and muon electric dipole moment (EDM) operators are discussed. Previously, $\barθ$ contribution to the electron EDM operator was calculated by Choi and Hong. However, the effect of CP-violating three meson coupling was missing there. We include this missing contribution for the first time in the literature, and reevaluate the Wilson coefficients of the lepton EDM operator. We obtain $d_e = - (2.2-8.6) \times 10^{-28} \barθ$ e-cm which is 15 - 70 % of the result obtained in Choi and Hong. We also estimated the …
The simplest unified extension of the Minimal Supersymmetric Standard Model with bilinear R--Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino anomalies.Despite the smallness of neutrino masses R-parity violation is observable at present and future high-energy colliders, providing an unambiguous cross-check of the model.
We predict CP violation in the long baseline accelerator experiments taking into consideration the recent LSND data and the atmospheric neutrino data. The estimated upper bound of CP violation is 0.006, which may be observable in the long baseline accelerator experiments. It is found that the upper bound increases to 0.01 if the LSND data is excluded. The matter effect, which is not CP invariant, is found to be very small in the case we consider.
We show that if the lepton flavor violating $μ\rightarrow e γ$ process is observed in the MEG II experiment, the initial density of primordial black holes (PBHs) can be constrained with the scotogenic dark matter. As a benchmark case, if the PBH evaporation occurs in the radiation dominated era, the initial density may be $2\times 10^{-17} \lesssim β\lesssim 3 \times 10^{-16}$ for $\mathcal{O}$ (TeV) scale dark sector in the scotogenic model where $β=ρ_{\rm PBH}/ρ_{\rm rad}$ is the ratio of the PBH density $ρ_{\rm PBH}$ to the radiation density $ρ_{\rm rad}$ at the time of PBH formation. As an…
We study the CP violation effects from two types of neutrino mass matrices with (i) $(M_ν)_{ee}=0$, and (ii) $(M_ν)_{ee}=(M_ν)_{eμ}=0$, which can be realized by the high dimensional lepton number violating operators $\bar \ell_R^cγ^μL_L (D_μΦ)Φ^2$ and $\bar \ell_R^c l_R (D_μΦ)^2Φ^2$, respectively. In (i), the neutrino mass spectrum is in the normal ordering with the lightest neutrino mass within the range $0.002\,{\rm eV}\lesssim m_0\lesssim 0.007\,{\rm eV}$. Furthermore, for a given value of $m_0$, there are two solutions for the two Majorana phases $α_{21}$ and $α_{31}$, whereas the Dirac ph…
The simplest unified extension of the Minimal Supersymmetric Standard Model with bilinear R--Parity violation provides a predictive scheme for neutrino masses which can account for the observed atmospheric and solar neutrino parameters. Despite the smallness of neutrino masses R-parity violation is observable at present and future high-energy colliders, providing an unambiguous cross-check of the model.
Opaque detectors are a recently proposed novel detector concept where an opaque scintillator aligned with wavelength-shifting fibers is used to enable the discrimination of electron neutrinos and antineutrinos with a rather low energy threshold. In this work, we investigate the potential effects of the enhanced detection capabilities of the opaque detectors in accelerator neutrino experiments. Focusing on the energy threshold, energy resolution, detection efficiency and background suppression in the analysis of electron-like events, we determine whether using opaque detectors could lead to imp…
We constrain some lepton flavor violating vertices in the context of the two Higgs doublet model type III, assuming that the lightest scalar Higgs mass $% m_{h^{0}} $is about $115 $GeV. Specifically, based on the $g-2 $muon factor and the decay width of$ μ\to eγ$,$ $the following quite general bounds are obtained:$ 7.62\times 10^{-4}\lesssim ξ_{μτ}^{2}\lesssim 4.44\times 10^{-2}, $ $ξ_{eτ}^{2}\lesssim 2.77\times 10^{-14}$. Additionally, based on the processes $τ\to μγ$, and $τ\to μμμ$, bounds on $ξ_{ττ} $and $ξ_{μμ} $are also gotten, such constraints on these parameters$ $still give enough roo…
A general introduction to Lorentz and CPT violation is presented. The observable effects of the breakdown of such fundamental symmetries in neutrinos are outlined and different experimental searches of some of the key signals of Lorentz violation are discussed. A novel powerful method to study model-independent neutrino oscillations is reviewed and then used to illustrate a new global model of neutrino oscillations based on Lorentz violation consistent with atmospheric, accelerator, reactor, and solar neutrino data.
Evidences for neutrino oscillations coming from atmospheric and solar observations can be probed by terrestrial long baseline experiments. This requires accelerator beams or nuclear power plants. The current status of these searches as well as future activities are discussed. A precise determination of all matrix elements and searches for a leptonic CP-violation will be possible with high intensity accelerator beams currently discussed in the context of neutrino factories.
We propose to use the unique event topology and reconstruction capabilities of liquid argon time projection chambers to study sub-GeV atmospheric neutrinos. The detection of low energy recoiled protons in DUNE allows for a determination of the leptonic $CP$-violating phase independent from the accelerator neutrino measurement. Our findings indicate that this analysis can exclude several values of $δ_{CP}$ beyond the $3σ$ level. Moreover, the determination of the sub-GeV atmospheric neutrino flux will have important consequences in the detection of diffuse supernova neutrinos and in dark matter…
We point out the possibility that reactor measurement of theta_{13}, when combined with high-statistics nu_e appearance accelerator experiments, can detect leptonic CP violation. Our proposal is based on a careful statistical analysis under reasonable assumptions on systematic errors, assuming 2 years running of the neutrino mode J-PARC -> Hyper-Kamiokande experiment and a few years running of a reactor experiment with 100 ton detectors at the Kashiwazaki-Kariwa nuclear power plant. We show that the method can be arranged to be insensitive to the intrinsic parameter degeneracy but is affected …
The new round of experiments, MEG II, COMET/Mu2e, and Mu3e, would soon start to push the $μ\to eγ$, $μN \to eN$ conversion, and $μ\to 3e$ frontier, while Belle II would probe $τ\to μγ$ and $τ\to 3μ$. In the general two Higgs doublet model with extra Yukawa couplings, we show that all these processes probe the lepton flavor violating (LFV) dipole transition that arises from the two loop mechanism, with scalar-induced contact terms subdominant. This is because existing data suggest the extra Yukawa couplings $ρ_{μe},\, ρ_{ee} \lesssim λ_e$, while $ρ_{τμ},\, ρ_{ττ} \lesssim λ_τ$ and $ρ_{tt} \less…
We study lepton flavour-violating interactions which could result in the $τ$-lepton production in the $ν_μN$ scattering or in $μ\to τ$ conversion on nucleons at high energies. Phenomenological bounds on the strength of $\barτν_μ\bar{q}q^{'}$ interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for $ν_μ - ν_τ$ oscillations. Some of these bounds supersede limits from rare decays. We also propose a ``missing energy'' type experiment searching for $μ- τ$ conversion on nucleons. The experiment can be performed at a present accelerator or at a future n…
We study the connection between quark and lepton mass matrices in a supersymmetric SO(10) GUT model in six dimensions, compactified on an orbifold. The physical quarks and leptons are mixtures of brane and bulk states. This leads to a characteristic pattern of mass matrices and high-energy CP violating phases. The hierarchy of up and down quark masses determines the CKM matrix and most charged lepton and neutrino masses and mixings. The small hierarchy of neutrino masses is a consequence of the mismatch of the up and down quark mass hierarchies. The effective CP violating phases in the quark s…
We consider effects of CP violating phases in μand A_t parameters in the effective supersymmetric standard model on B\to X_s l^+ l^- and ε_K. Scanning over the MSSM parameter space with experimental constraints including edm constraints from Chang-Keung-Pilaftsis (CKP) mechanism, we find that the Br(B\to X_s l^+ l^-) can be enhanced by upto \sim 85 % compared to the standard model (SM) prediction, and its correlation with Br(B \to X_s γ) is distinctly different from the minimal supergravity scenario. Also we find 1 \lesssim ε_K / ε_K^{SM} \lesssim 1.4, and fully supersymmetric CP violation in …
In a minimal supersymmetric extension of the standard model (MSSM) with explicit CP violation a mass of the lightest Higgs boson H_1 in the range 7 GeV} < M_{H_1} < 10 GeV is experimentally allowed by present accelerator limits. In the same scenario a lightest neutralino as light as 2.9 GeV can be a viable dark matter candidate, provided that a departure from the usual GUT relation among gaugino masses is assumed.
We investigate how the observed neutrino data can be accommodated by R-parity violation in Split Supersymmetry. The atmospheric neutrino mass and mixing are explained by the bilinear parameters $ξ_i$ inducing the neutrino-neutralino mixing as in the usual low-energy supersymmetry. Among various one-loop corrections, only the quark-squark exchanging diagrams involving the order-one trilinear couplings $λ'_{i23,i32}$ can generate the solar neutrino mass and mixing if the scalar mass $m_S$ is not larger than $10^9$ GeV. This scheme requires an unpleasant hierarchical structure of the couplings, e…
Lorentz- and CPT-violating effects initiating two-body electromagnetic flavor-changing decays of charged leptons are studied in the framework of Lorentz-violating effective field theory. An analysis of data from experiments at the Paul Scherrer Institute and at the Stanford Linear Accelerator measuring the branching ratios of these decays provides 576 constraints on independent flavor-changing effects in the charged-lepton sector, consistent with no Lorentz and CPT violation at the level of parts in $10^{-13}$ GeV$^{-1}$ to $10^{-9}$ GeV$^{-1}$.
We consider the effects of R-parity violation due to the inclusion of a bilinear $μ^\prime L H_u$ superpotential term in high scale supersymmetric models with an EeV scale gravitino as dark matter. Although the typical phenomenological limits on this coupling (e.g. due to lepton number violation and the preservation of the baryon asymmetry) are relaxed when the supersymmetric mass spectrum is assumed to be heavy (in excess of the inflationary scale of $3 \times 10^{13}$ GeV), the requirement that the gravitino be sufficiently long-lived so as to account for the observed dark matter density, le…
Some theoretical aspects of 3-flavour (3f) neutrino oscillations are reviewed. These include: general properties of 3f oscillation probabilities; matter effects in ν_μ\leftrightarrow ν_τoscillations; 3f effects in oscillations of solar, atmospheric, reactor and supernova neutrinos and in accelerator long-baseline experiments; CP and T violation in neutrino oscillations in vacuum and in matter, and the problem of U_{e3}.
An increasing number of experiments at the Belle, BNL, CERN, DAΦNE and SLAC accelerators are confirming the violation of time reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and calls for a major shift in the way we think about time. Here we show that processes which violate T symmetry induce destructive interference between different paths that the universe can take through time. The interference eliminates all paths except for two that represent continuously forwards and continuously backwards time evolution. Evidence from the accelerator …
In this talk we discuss the possibility to measure CP violation in neutrino oscillation experiments using the neutrino beam with energy which is lower (E_ν\gsim 100 MeV) than the one usually considered (typically > 1 GeV) in accelerator experiments. The advantage of using such lower energy neutrino beam is that despite the smaller detection cross sections, the effect of CP violation is larger and the optimal length of baseline can be rather short, 30-50 km, being free from matter effect contamination.
Future long-baseline neutrino experiments will measure neutrino oscillation properties with unprecedented precision and will search for clear signatures of CP violation in the leptonic sector. Near detectors can measure the neutrino-electron scattering with high statistics, giving the chance for its precise measurement. We study, in this work, the expectations for the measurement of radiative corrections in this process. We focus on the determination of contributions that are exclusive to the neutrino channels, particularly on the neutrino charge radius. We illustrate how the perspectives in a…
Recent data from long-baseline neutrino oscillation experiments have provided new information on θ_{13}, hinting that 0.01\lesssim sin^2 2θ_{13} \lesssim 0.1 at 2 sigma C.L. Confirmation of this result with high significance will have a crucial impact on the optimization of the future long-baseline oscillation experiments designed to probe the neutrino mass ordering and leptonic CP violation. In this context, we expound in detail the physics reach of an experimental setup where neutrinos produced in a conventional wide-band beam facility at CERN are observed in a proposed Giant Liquid Argon de…
We perform a detailed combined fit to the $\overline ν_e \rightarrow \overline ν_e$ disappearence data of the Daya Bay experiment and the appearance $ν_μ \rightarrow ν_{e}$ and disappearance $ν_μ \rightarrow ν_μ$ data of the Tokai to Kamioka (T2K) one in the presence of two models of new physics affecting neutrino oscillations, namely a model where sterile neutrinos can propagate in a large compactified extra dimension and a model where non-standard interactions (NSI) affect the neutrino production and detection. We find that the Daya Bay $\oplus$ T2K data combination constrains the largest ra…
We investigate matter-induced (or extrinsic) CPT violation effects in neutrino oscillations in matter. Especially, we present approximate analytical formulas for the CPT-violating probability differences for three flavor neutrino oscillations in matter with an arbitrary matter density profile. Note that we assume that the CPT invariance theorem holds, which means that the CPT violation effects arise entirely because of the presence of matter. As special cases of matter density profiles, we consider constant and step-function matter density profiles, which are relevant for neutrino oscillation …
In R-parity-violating supersymmetry the lightest neutralino can be very light, even massless. For masses in the range $500$ MeV$\lesssim m_{\tildeχ^0_1}\lesssim 4.5$ GeV the neutralino can be produced in hadron collisions from rare meson decays via an R-parity violating coupling, and subsequently decay to a lighter meson and a charged lepton. Due to the small neutralino mass and for small R-parity violating coupling the lightest neutralino is long-lived, leading to displaced vertices at fixed-target and collider experiments. In this work, we study such signatures at the proposed experiments AN…
Dark Matter as a Source for Lepton Flavor Violation
Universidad Andres Bello（安德烈斯贝略大学）；Universidade Federal da Paraíba（帕拉伊巴联邦大学）；International Institute of Physics, Universidade Federal do Rio Grande do Norte（北里奥格兰德联邦大学国际物理研究所）；Departamento de Física, Universidade Federal do Rio Grande do Norte（北里奥格兰德联邦大学物理系）；Millennium Institute for Subatomic Physics at High-Energy Frontier (SAPHIR)（高能前沿亚原子物理学千年研究所（SAPHIR））；Departamento de Física, Facultad de Ciencias, Universidad de La Serena（拉塞雷纳大学理学院物理系）
The scalar nonstandard interactions (NSI) can also introduce matter effect for neutrino oscillation in a medium. Especially the recent Borexino data prefers nonzero scalar NSI, $η_{ee} = - 0.16$. In contrast to the conventional vector NSI, the scalar type contributes as a correction to the neutrino mass matrix rather than the matter potential. Consequently, the scalar matter effect is energy independent while the vector one scales linearly with neutrino energy. This leads to significantly different phenomenological consequences in reactor, solar, atmospheric, and accelerator neutrino oscillati…
The fourth generation can give the correct trend of S_{phi K^0}, S_{pi^0 K^0} < sin2phi_1/beta, as indicated by data, and the effect, being largely leading order, is robust against hadronic uncertainties. The effect on S_{eta' K^0}, however, is diluted away by hadronic effects, and S_{eta' K^0} \simeq sin2phi_1/beta is expected. The near maximal arg[V^*_{t's}V_{t'b}] \lesssim 90^\circ that is needed could resolve the unequal direct CP violation seen in B -> K^+ pi^- and K^+ pi^0 modes, and is consistent with b ->s l^+l^- and B_s mixing constraints.
The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, has brought neutrino physics to the precision era. We note that CP effects in oscillation phenomena could be difficult to extract in the presence of unitarity violation. As a result upcoming dedicated leptonic CP violation studies should take into account the non-unitarity of the lepton mixing matrix. Restricting non-unitarity will shed light on the seesaw scale, and thereby guide us towards the new physics responsible for neutrino mass generation.
Bilinear R-parity violation provides an attractive origin for neutrino masses and mixings. In such schemes the gravitino is a viable decaying dark matter particle whose R-parity violating decays lead to monochromatic photons with rates accessible to astrophysical observations. We determine the parameter region allowed by gamma-ray line searches, dark matter relic abundance and neutrino oscillation data, obtaining a limit on the gravitino mass $m_{\tilde G} \lsim$ 1-10 GeV corresponding to a relatively low reheat temperature $T_R \lsim$ few $\times 10^7-10^8$ GeV. Neutrino mass and mixing param…
The measurements of the parameters of the neutrino mixing matrix in the present and future neutrino oscillation experiments at accelerators are presented. The perspectives for high intensity new neutrino facilities as SuperBeams, BetaBeams and Neutrino Factories devoted to precise measurements subleading numu to nue oscillation parameters at the atmospheric scale are discussed. Emphasis is on the determination of the currently unknown 1-3 sector of the leptonic mixing matrix (i.e. the mixing between the first and third generation and the CP violating Dirac phase) and on possible experimental p…
Lepton-number violation can be induced by the exchange of an on-shell Majorana neutrino $N$ in semileptonic $|ΔL|=2$ decays of the $B_s$ meson, $B_s^0 \to P^-π^-μ^+ μ^+$ with $P=K, D_s$. We investigate the production of such a heavy sterile neutrino through these four-body $μ^+μ^+$ channels and explore the sensitivity that can be reached at the LHCb and CMS experiments. For heavy neutrino lifetimes of $τ_N$ = [1, 100, 1000] ps and integrated luminosities collected of 10 and 50 fb${}^{-1}$ at the LHCb and 30, 300, and 3000 fb${}^{-1}$ at the CMS, we find a significant sensitivity on branching f…
The low-energy neutrino physics constraints on the TeV scale type I see-saw scenarios of neutrino mass generation are revisited. It is shown that lepton charge (L) violation, associated to the production and decays of heavy Majorana neutrinos N_{j} having masses in the range of M_j \sim (100 ÷1000) GeV and present in such scenarios, is hardly to be observed at ongoing and future particle accelerator experiments, LHC included, because of very strong constraints on the parameters and couplings responsible for the corresponding |ΔL| = 2 processes. If the heavy Majorana neutrinos N_j are observed …
Bilinear R-parity violation (BRPV) provides the simplest intrinsically supersymmetric neutrino mass generation scheme. While neutrino mixing parameters can be probed in high energy accelerators, they are unfortunately not predicted by the theory. Here we propose a model based on the discrete flavor symmetry $A_4$ with a single R-parity violating parameter, leading to (i) correct Cabbibo mixing given by the Gatto-Sartori-Tonin formula, and a successful unification-like b-tau mass relation, and (ii) a correlation between the lepton mixing angles $θ_{13}$ and $θ_{23}$ in agreement with recent neu…
IceCube has observed a flux of cosmic neutrinos, with a "bump" in the energy range $10 \lesssim E/{\rm TeV} \lesssim 100$ that creates a $3σ$ tension with gamma-ray data from the Fermi satellite. This has been interpreted as evidence for a population of hidden cosmic-ray accelerators. We propose an alternative explanation of this conundrum on the basis of cold dark matter which decays into sterile neutrinos that after oscillations produce the bump in the cosmic neutrino spectrum.
Direct Detection of Ultralight Dark Matter via Charged Lepton Flavor Violation
Northwestern University（西北大学）；Fermilab（费米国家加速器实验室）；Tel-Aviv University（特拉维夫大学）；Johannes Gutenberg University（约翰内斯·古腾堡大学）；University of Chicago（芝加哥大学）；University of Cincinnati（辛辛那提大学）
