Related papers: $\tau$ physics at LHCb
At the back of succeeding measurements of anomalies in semileptonic decays at LHCb and several collider experiments hinting at the possible violation of lepton flavor universality, we undertake a concise review of theoretical foundations of…
We consider lepton-flavor violation in strangeness changing ($|\Delta S|=1$) semileptonic $\tau$-lepton decays arising from new physics encoded in a standard model effective Lagrangian. Its invariance under the standard model gauge group…
A measurement of the ratio of the branching fractions, $R_{\tau/e} = B(W \to \tau \nu)/ B(W \to e \nu)$, is performed using a sample of $W$ bosons originating from top-quark decays to final states containing $\tau$-leptons or electrons.…
Using the ZEUS detector at the HERA electron-proton collider, we have searched for lepton flavor violation in ep collisions at a center-of-mass energy s^1/2 of 300 GeV. Events of the type e + p -> lepton + X with a final-state lepton (mu or…
The charged lepton flavor violation process is a clean and sensitive probe of new physics beyond the Standard Model. A sensitivity study is performed to the process $\tau^- \to \gamma \mu^-$ based on a 3~fb$^{-1}$ inclusive Monte Carlo…
In this letter, we use LHC data from the Drell-Yan processes $pp\to\ell_i\ell_j$ (with $i\neq j$) to derive model-independent upper limits on lepton-flavor-violating meson decays. Our analysis is based on an Effective Field Theory (EFT)…
The CMS collaboration has reported a possible lepton flavour violating (LFV) signal $h\to\mu\tau$. Whereas this does not happen in the standard model (SM), we point out that new physics responsible for this type of decay would, in general,…
We explore the limits on lepton-flavor universality (LFU) violation in theories where the hierarchy problem is solved by means of a warped extra dimension. In those theories LFU violation, in fermion interaction with Kaluza-Klein modes of…
We present a complete analysis of Lepton Flavor Universality (LFU) violations in leptonic $\tau$ decays in motivated models addressing the $B$-physics anomalies, based on the $SU(4)\times SU(3)\times SU(2)\times U(1)$ gauge group. We show…
We discuss sensitivities to lepton flavor violating (and conserving) interactions at future muon colliders, especially at $\mu^+\mu^+$ colliders. Compared with the searches for rare decays of $\mu$ and $\tau$, we find that the TeV-scale…
We study lepton flavour-violating interactions which could result in the $\tau$-lepton production in the $\nu_{\mu}N$ scattering or in $\mu \to \tau$ conversion on nucleons at high energies. Phenomenological bounds on the strength of…
Several experiments observed deviations from the Standard Model (SM) in the flavour sector: LHCb found a $4-5\,\sigma$ discrepancy compared to the SM in $b\to s\mu^+\mu^-$ transitions (recently supported by an Belle analysis) and CMS…
We present in a full analytic form the partial widths for the lepton flavour violating decays $\mu^\pm \to e^\pm e^+ e^-$ and $\tau^\pm \to \ell^\pm \ell'^{+} \ell'^{-}$, with $\ell,\ell'=\mu,e$, mediated by neutrino oscillations in the…
Present measurements of b->c tau nu and b->u tau nu transitions differ from the standard model predictions of lepton flavor universality by almost 4sigma. We examine new physics interpretations of this anomaly. An effective field theory…
Extant anomalies in several semileptonic $B$-meson decays argue for physics beyond the Standard Model. Measurements of both neutral-current decays (such as $R_K$, $R_{K^*}$ and $B_s\rightarrow \phi\mu\mu$) as well as charged-current ones-…
The LHCb experiment at the Large Hadron Collider specialises in high-precision measurements of flavour physics with hadrons containing $b$ and $c$ quarks. Lepton flavour universality tests provide an accurate and clear approach to…
The BaBar experiment recorded 471 x 10^6 BBbar pairs at the Y(4S) resonance (corresponding to an integrated luminosity of 429 fb^-1). We present here a selection of recent results from the BaBar collaboration: search for lepton-number…
Searches for $B$ mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either $\Lambda_c$ or $\Lambda$ and the lepton is a muon or an electron. These decays violate both baryon and lepton number…
The possibility to discriminate between different operators contributing to lepton flavour violating tau decays is discussed within an effective field theory framework. Correlations among decay rates in different channels as well as…
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…