Related papers: $b\to s\tau^+\tau^-$ Physics at Future $Z$ Factori…

Measurements in $W^+W^-$ events at LEP2 and in $B$ hadron semileptonic decays at B factories and LHCb provide intriguing hints of a violation of lepton universality in the charged current coupling of tau leptons relative to those for…

We have just entered a new round in the testing of the flavour sector of the Standard Model through high-precision measurements of B-meson decays. A particularly exciting aspect is the exploration of the B_s-meson system at LHCb. We focus…

We estimate that the LHC could set bounds BR(Z -> mu^\pm e^\mp) < 4.1 * 10^{-7} and BR(Z -> tau^\pm mu^\mp)< 3.5 * 10^{-6} (at 95% C.L.) with 20 inverse fb of data at 8 TeV. A similar sensitivity can be anticipated for Z -> tau^\pm e^\mp,…

The $Z'$-gauge boson in an $U(1)_{L_\mu-L_\tau}$ gauge symmetry has two interesting features: one is its vector couplings to the charged leptons, and the other is the decoupling from the electron. Based on these properties, we investigate…

The persisting anomalous data in semileptonic B-decays point towards New Physics models exhibiting large sources of Lepton Flavour Universality Violation. In this work we generalise previous studies by considering frameworks which include…

Three new observables for Z-factory to measure the weak dipole moment of $\tau$ lepton ($d_w^\tau$) are proposed. As those observables employed at LEP-I, the new observables depend on the real and imaginary parts of $d_w^\tau$ linearly,…

Here we update the predictions for lepton flavour violating tau and muon decays, $l_j \to l_i \gamma$, $l_j \to 3 l_i$, and $\mu-e$ conversion in nuclei. We work within a SUSY-seesaw context where the particle content of the Minimal…

We propose a generation dependent lepton/baryon gauge symmetry, $U(1)_{B_3 - x_\mu L_\mu - x_\tau L_\tau} \equiv U(1)_X$ (with $x_\mu + x_\tau =1$ for anomaly cancellation), as a possible solution for the $b \rightarrow s \mu^+ \mu^-$…

Over the last few years LHCb with present energies found some discrepancies in $b\to s\ell^+\ell^-$ FCNC transitions including anomalies in the angular observables of $B\to K^*\mu^+\mu^-$, particularly in $P_5^\prime$, in low dimuon mass…

Charged-lepton-flavor-violation is predicted in several new physics scenarios. We update the analysis of $\tau$ lepton decays into a light charged lepton ($\ell$ = $e^{\pm}$ or $\mu^{\pm}$) and a vector meson ($V^0$ = $\rho^0$, $\phi$,…

The lepton flavor violating $Z^{\prime}\to\tau\mu$ decay is studied in the context of several extended models that predict the existence of the new gauge boson named $Z^\prime$. A calculation of the strength of the lepton flavor violating…

A search for charged lepton flavour violation in $\tau \to 3\mu$ decays is performed in $pp$ collisions at a centre-of-mass energy of 13 TeV using ATLAS data collected between 2016 and 2018, corresponding to an integrated luminosity of 137…

Semileptonic flavor changing neutral current transitions with a pair of neutrinos in the final state are very accurately determined in the standard model (SM) and thus provide an accurate and sensitive probe for physics beyond the SM. Until…

Within the framework of the next to the minimal supersymmetric (SUSY) extension of the Standard Model (SM) with a local B-L gauge symmetry (N-B-LSSM), we study lepton flavor violating (LFV) $\tau\rightarrow e M^+ M^-$ decays: $\tau…

In recent years, significant experimental indications that point towards Lepton Flavour Universality violating effects in B-decays, involving $b \to c \tau \nu$ and $b \to s \ell^+ \ell^-$ have been accumulated. A possible New Physics…

A search for the lepton-flavour violating decays $B^0 \to K^{*0} \mu^\pm e^\mp$ and $B_s^0 \to \phi \mu^\pm e^\mp$ is presented, using proton-proton collision data collected by the LHCb detector at the LHC, corresponding to an integrated…

We search for the rare flavor-changing neutral current process $B^{+}\rightarrow K^{+}\tau^{+}\tau^{-}$ using data from the BABAR experiment. The data sample, collected at the center-of-mass energy of the $\Upsilon{(4S)}$ resonance,…

We present a search for the lepton-flavor-violating decays $B{}^0_s \rightarrow \ell^{\mp}\tau^{\pm}$, where $\ell = e, \mu$, using the full data sample of $121~\mathrm{fb}^{-1}$ collected at the $\Upsilon(5S)$ resonance with the Belle…

Precise measurement of the Electric Dipole Moment (EDM) and anomalous magnetic moment ($g$-2) of particles are important tests of Beyond Standard Model (BSM) physics. It is generally believed that the tau lepton couples more strongly to BSM…

The electric and magnetic dipole moments of the electron and of the muon provide stringent tests of the Standard Model and sensitive probes of new physics. By contrast, the corresponding dipole moments of the $\tau$ lepton remain weakly…