相关论文: Extra gauge bosons and lepton flavor universality …
We present a global analysis of the current $B$-meson flavor anomalies and extend it to the baryonic sector through the decay $\Lambda_b^0 \to \Lambda_c^+(\to \Lambda^0 \pi^+) \tau^-(\to \pi^- \nu_\tau)\bar{\nu}_\tau$. The lepton flavor…
In this letter we propose a strategy for discerning if new physics in the Wilson coefficient ${\cal C}_{9\mu}$ is dominantly lepton flavour universality violating or if it contains a sizable lepton flavour universal component (${\cal…
In this study, we investigate the lepton flavor violation (LFV) of Z gauge boson decaying into two different flavor charged leptons $Z\rightarrow l_i l_j$ ($Z\rightarrow \tau \mu$, $Z\rightarrow \tau e$ and $Z\rightarrow \mu e$). This work…
We present a search for the radiative leptonic decays B+ -> e+ nu gamma and B+ -> mu+ nu gamma using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in Upsilon(4S)…
The ratio of branching ratios of the $W$ boson to muons and electrons, $R^{\mu/e}_W=B(W\rightarrow \mu\nu)/B(W\rightarrow e\nu)$, has been measured using 140 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV collected with the ATLAS…
The electroweak sector of the Standard Model contains three generations of charged leptons $\ell^-\in\{e^-,\mu^-,\tau^-\}$ as exact replicas of each other, except for their Yukawa couplings to the Higgs that determine their masses. The…
We present an updated and improved global fit analysis of current flavor and electroweak precision observables to derive bounds on unitarity deviations of the leptonic mixing matrix and on the mixing of heavy neutrinos with the active…
Three recent measurements of leptonic and semileptonic decays of $B$ mesons are presented here. All results use the full Belle II Run 1 $e^+e^- \to \Upsilon(4S) \to B\bar{B}$ dataset of 365 fb$^{-1}$. We present one leptonic $B$ decay…
The flavour lepton symmetry is gauged for both the Standard Model flavor group and its extension with three degenerate right-handed neutrinos. As a consequence of anomaly cancellation, exotic leptons are introduced which induce a see-saw…
We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the…
Lepton flavor violating Higgs boson decays (LFVHD) are studied in the context of the Minimal Supersymmetric Standard Model (MSSM) being embeded in a mSUGRA scenario that is enlarged with three right handed neutrinos and their supersymmetric…
We present Standard Model predictions for lepton flavour universality ratios of inclusive $B\to X_{(c)} \ell \bar\nu_\ell$. For the $\ell=\mu,e$, these ratios are very close to unity as expected. For the $\tau$ mode, we update the SM…
In this work the following lepton flavor violating $\tau$ and $\mu$ decays are studied: $\tau^- \to \mu^- \mu^- \mu^+$, $\tau^- \to e^- e^- e^+$, $\mu^- \to e^- e^- e^+$, $\tau^- \to \mu^- \gamma$, $\tau^- \to e^- \gamma$ and $\mu^- \to e^-…
We present a search for the decay B+ -> tau+ nu using 288 inverse femtobarns of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed semileptonic B decay…
Models based on the extended symmetry gauge $SU(3)_c \otimes SU(3)_L \otimes U(1)_Y$ can be build up with a leptonic sector consistent of five triplets in different $SU(3)_L$ representations where additional heavy fermions are included.…
The first test of lepton flavor universality between muons and electrons using $B^+ \to K^+\pi^+\pi^-\ell^+\ell^-$ ($\ell=e,\mu$) decays is presented. The measurement is performed with data from proton-proton collisions collected by the…
One of the exciting results in flavor physics in recent times is the $R_D$/$R_{D^*}$ puzzle. The measurements of these flavor ratios performed by the B-factory experiments, BaBar and Belle, and the LHCb experiment are about $4\sigma$ away…
We propose improved Lepton Flavor Universality (LFU) ratios in semileptonic $P\to V \ell \bar{\nu}$ decays, when comparing $\mu$ and $\tau$ modes, that minimize the theoretical form-factor uncertainties. These optimized ratios are obtained…
We present a search for the decay B^+ --> tau^+ nu using $383 \times 10^{6}}$ BBbar pairs collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II B Factory. We select a sample of events with one completely…
General expressions for one-loop contributions associated with lepton-flavor violating decays of the standard model-like Higgs boson $h\to e_b^\pm e_a^\mp$ and gauge boson $Z\to e^\pm_b e_a^\mp$ are introduced in the unitary gauge. The…