Related papers: Dark light shining on $B\to K^{(*)} E_{\rm miss}$
This contribution illustrates a new search for the flavor-changing neutral-current decay ${B^+ \to K^+ \nu \bar \nu}$ performed by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. In this study, a…
We present a fermionic dark matter model mediated by the hidden gauge boson. We assume the QED-like hidden sector which consists of a Dirac fermion and U(1)$_X$ gauge symmetry, and introduce an additional scalar electroweak doublet field…
A non perturbative proof of the mass generation of fermions via the Higgs mechanism is given. This is done by showing exponential decay of the two point fermionic correlation function in a weakly coupled U(1) Higgs-Yukawa theory on a unit…
A new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework. Two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an…
The ${\rm U(1)}_{L_\mu - L_\tau}$ model is anomaly-free with the Standard Model (SM) fermion content, and can make substantial contributions to the muon $(g-2)$ at the level of $\Delta a_\mu \sim O(10) \times 10^{-10}$ for $M_{Z'} \sim…
Belle~II has unique sensitivity for a broad class of models postulating the existence of dark matter particles with masses in the MeV--GeV range. We present recent world-leading results from Belle~II searches for several non-SM particles.…
Scenarios in which right-handed light Standard Model fermions couple to a new gauge group, $U(1)_{T3R}$ can naturally generate a sub-GeV dark matter candidate. But such models necessarily have large couplings to the Standard Model,…
We consider a simple model of a dark sector with a chiral $U(1)$ gauge symmetry. The anomaly-free condition requires at least five chiral fermions. Some of the fermions acquire masses through a vacuum expectation value of a Higgs field, and…
In a Dark left-right gauge model, the neutral component of right-handed lepton doublet is odd under generalized R-parity and thus the lightest one serves as the dark matter (DM) candidate. The coannihilation of the dark matter with the…
Combining the dark matter and muon $g-2$ anomaly, we study the $U(1)_{L_\mu-L_\tau}$ breaking phase transition, gravitational wave spectra, and the direct detection at the LHC in an extra $U(1)_{L_\mu-L_\tau}$ gauge symmetry extension of…
In this work, we predict the spectroscopy behavior of these light unflavored vector mesons with masses at the range of $2.4\sim 3$ GeV, which are still missing in the experiment. By presenting their mass spectrum and studying their two-body…
Semileptonic ${B}$ meson decays involving low-mass charged leptons ${e}$ or ${\mu}$ are expected to be free of non-Standard Model contributions and therefore play a critical role in determinations of ${\vert V_{ub} \vert}$ and ${\vert…
An extended Higgs sector may allow for new scalar particles well below the weak scale. In this work, we present a detailed study of a light scalar $S$ with enhanced coupling to leptons, which could be responsible for the existing…
We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new…
Due to the strong constrain from the LUX experiment, the scalar portal dark matter can not generally explain a gamma-ray excess in the galactic center by the annihilation of dark matter into $b\bar{b}$. With the motivation of eliminating…
The new gauge boson $Z'$ in $U(1)_{B-L}$ is widely considered as the mediator of dark matter. In this paper, we propose the conversion-driven dark matter in $U(1)_{B-L}$. The dark sector contains two Dirac fermions $\tilde{\chi}_1$ and…
We consider the lepton number violating decays $B \to \mu^{\pm} \mu^{\pm} \pi^{\mp}$ and $B \to D^{(*)} \mu^{\pm} \mu^{\pm} \pi^{\mp}$ which may be detected at LHCb and Belle-II experiments; and $B \to \mu^{\pm} \mu^{\pm} e^{\mp} \nu$ and…
Dark matter is postulated to be a neutral Dirac fermion, charged under a dark $U(1)_D$ gauge symmetry. Scalar partners of the quarks and leptons are also charged under $U(1)_D$. The dark gauge boson $Z_D$ and the dark Higgs boson $h_D$…
The CMS and ATLAS collaborations recently published their results searching for light Higgs bosons, using the complete Run 2 data of the LHC. Both reported an excess in the diphoton invariant mass distribution at $m_{\gamma \gamma} \simeq…
A very light (GeV scale) dark gauge boson ($Z'$) is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the $3.6 \sigma$ deviation in the muon $g$-2 measurement. We suggest top quark decays…