Related papers: Lepton Flavour Universality in $\tau$ decays
Motivated by the recent LHCb announcement of a $3.1\sigma$ violation of lepton-flavor universality in the ratio $R_K=\Gamma(B\to K\mu^+\mu^-)/\Gamma(B\to K e^+ e^-)$, we present an updated, comprehensive analysis of the flavor anomalies…
I review the recent theoretical progress on the study of tree-level semileptonic $b\to c$ decays. After briefly reviewing the latest developments on the exclusive determinations of $|V_{cb}|$, I discuss the hints on lepton flavor…
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…
Lepton Flavor Violating (LFV) decays are forbidden in the Standard Model (SM) and to explore them one has to go beyond it. The flavor changing neutral current induced Lepton Flavor Conserving and LFV decays of $K$ and $B$ mesons are…
Lepton flavor violation (LFV) is studied within a realistic unified framework, based on supersymmetric SO(10) or an effective G(224) = SU(2)_L\times SU(2)_R\times SU(4)^c symmetry, that successfully describes (i) fermion masses and mixings,…
The B Factories have generated a large amount of new results on the tau lepton. The present status of some selected topics on tau physics is presented: charged-current universality tests, bounds on lepton-flavour violation, the…
We propose measurements of weighted differences of the angular observables in the rare decays $B \to K^*\ell^+\ell^-$. The proposed observables are very sensitive to the difference between the Wilson coefficients $\mathcal{C}_9^{(e)}$ and…
In recent years, evidence for lepton flavour universality violation beyond the Standard Model has been accumulated. In this context, a singly charged $SU(2)_L$ singlet scalar ($\phi^\pm$) is very interesting, as it can only have flavour…
Gauged extensions [$SU(2)_L\otimes U(1)_Y\otimes U(1)_X$] of the standard $SU(2)_L\otimes U(1)_Y$ model obtained without extending the fermion content of the model are studied. Models that are possible when $U(1)_X$ is identified with some…
The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the…
We present two recent developments on lepton flavour violation in the MSSM. 1) The supersymmetric seesaw mechanism can be realized through the exchange of heavy SU(2)_W-triplet states, rather than `right-handed' neutrinos. In this scenario…
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…
The most efficient way to extend the Standard Model of particle theory so that it accommodates the observed B anomalies is the hypothesis of a leptoquark which is a color-triplet weak-singlet boson with electric charge $Q=+\frac{2}{3}$. We…
The basic features of quark and lepton mass matrices can be successfully explained by natural minima of a generic potential with dynamical Yukawa fields invariant under the $[\mathrm{SU(3)}]^5\times \mathcal{O}(3)$ flavor symmetry. If this…
The most recent measurements of the observables $R_{D^{(*)}}$ are in tension with the Standard Model offering hints of New Physics in $b\rightarrow c \ell \bar{\nu}_{\ell}$ transitions. Motivated by these results, in this work we present an…
In supersymmetric~SO(10) with large $\tan\beta$ and Yukawa coupling unification $\lambda_t=\lambda_b=\lambda_\tau$, we compute the rates for lepton flavour violating processes. Experiments in progress or foreseen for $\mu\to e\gamma$,…
Recently, discrepancies of up to $4\,\sigma$ between the different determinations of the Cabibbo angle were observed. This "Cabibbo-angle anomaly" could be explained by lepton flavour universality (LFU) violating New Physics (NP) in the…
The measurements of several lepton flavor universality (LFU) violating observables in the decays induced by the quark level transition $b \to c \tau \bar{\nu}$ provide an inkling of plausible physics beyond the standard model of electroweak…
Motivated by the recent observation of lepton universality violation in the flavour changing charged current transitions $b \to c l \bar{\nu}_l$, we intend to scrutinize the lepton non-universality effects in rare semileptonic $B$ meson…
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…