Related papers: Four-lepton decays of neutral vector mesons
Very little is known about the mass spectrum of fermions in the standard model. In this talk, I point out that in the simplest extension of the standard model, in which all right-handed fields are singlets, it is quite possible that a…
We search for lepton-flavor-violating tau-> ell V^0 decays, where ell is an electron or muon and V^0 is one of the vector mesons rho^0, phi, omega, K*0 and K*0-bar. We use 854 fb^{-1} of data collected with the Belle detector at the KEKB…
We study the $d\Gamma / dq^2$ spectra and the branching fractions of the $D$ meson exclusive semileptonic decays with the lepton mass effects into consideration. We investigate their sensitivity to form factor models, and find that the…
We investigate the weak semileptonic decays of the charmonium $J/\psi$ and bottomonium $\Upsilon(1S)$ into a pseudoscalar meson, namely, the $J/\psi\to D_{(s)}\ell\bar{\nu}_\ell$ and $\Upsilon(1S)\to B_{(c)}\ell\bar{\nu}_\ell$ decays. We…
We give a short and basic introduction to our covariant Dyson-Schwinger-Bethe-Salpeter-equation approach using a rainbow-ladder truncated model of QCD, in which we investigate the leptonic decay properties of heavy quarkonium states in the…
We analyse the dependence of the rates of the LFV charged lepton decays mu to e + gamma, tau to e + gamma, tau to mu + gamma (l_i to l_j + gamma) and their ratios, predicted in the class of SUSY theories with see-saw mechanism of nu-mass…
We determine the decay rate to leptons of the ground-state $\Upsilon$ meson and its first radial excitation in lattice QCD for the first time. We use radiatively-improved NRQCD for the $b$ quarks and include $u$, $d$, $s$ and $c$ quarks in…
A search for heavy narrow resonances decaying into four-lepton final states from cascade decays of a Z' boson has been performed using proton-proton collision data at sqrt(s) = 8 TeV collected by the CMS experiment, corresponding to an…
We report a study of $B \to J/\psi(\ell^{+}\ell^{-})K$ decays, where $\ell$ represents an electron or a muon, using $e^{+}e^{-}$ collisions at the $\Upsilon(4S)$ resonance. The data were collected by the Belle II experiment at the SuperKEKB…
We present a search for ten baryon-number violating decay modes of $\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\Lambda…
We propose a phenomenological Lagrangian for the decay of the SU(3) nonets of the axial-vector mesons of $J^{PC}=1^{+-},1^{++}$ into a vector meson and a pseudoscalar constructed with tensor fields for the vector and axial-vector mesons.…
Using a counting scheme which treats pseudoscalar and vector mesons on equal footing, the decays of the narrow light vector mesons omega and phi into a dilepton and a pseudoscalar pi-meson or eta-meson, respectively, are calculated.…
The light vector mesons ($\rho$, $\omega$, and $\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\rho$ meson at normal nuclear densities and…
An examination of leptons in ${\Upsilon (4S)}$ events tagged by reconstructed $B$ decays yields semileptonic branching fractions of $b_-=(10.1 \pm 1.8\pm 1.4)\%$ for charged and $b_0=(10.9 \pm 0.7\pm 1.1)\%$ for neutral $B$ mesons. This is…
We have searched for neutrinoless $\tau$ lepton decays into $\ell$ and $V^0$, where $\ell$ stands for an electron or muon, and $V^0$ for a vector meson ($\phi$, $\omega$, $K^{*0}$, $\bar{K}^{*0}$ or $\rho^0$), using 543 fb$^{-1}$ of data…
We point out that lepton number violation is possible even if neutrinos are Dirac particles. We illustrate this by constructing a simple model that allows for lepton number violation by four units only. As a consequence, neutrinoless double…
We study the phenomenology of heavy neutral leptons (HNLs) in $B$-meson decays as probes of physics beyond the Standard Model. Focusing on the leptonic channels $B \to \mu N$ and $B \to \tau N$, we constrain the allowed regions in the…
We present a search for the charged lepton-flavor-violating decays $\Upsilon(1S)\rightarrow\ell\ell^\prime$ and radiative charged lepton-flavour-violating decays $\Upsilon(1S)\rightarrow\gamma\ell\ell^\prime$ [$\ell,\ell^\prime = e, \mu,…
Leptoquarks with mass in the region of $550-650$ GeV are a possible candidate for the recent excess seen by CMS in the $eejj$ and $e \nu jj$ channels. We discuss models where leptoquarks decay primarily to dark matter and jets, thereby…
Based on the picture that the $ f_0(1370), f_0(1710), f_2(1270), f'_2(1525), \bar{K}^{*0}_2(1430)$ resonances are dynamically generated from the vector-vector interaction, we study the decays $J/\psi \to \phi (\omega) f_0(1370)…