Related papers: Explaining the $R_{K}$ and $R_{D^{(*)}}$ anomalies…
We reconsider a model introducing a scalar leptoquark $\phi \sim (\mathbf{3}, \mathbf{1}, -1/3)$ to explain recent deviations from the standard model in semileptonic $B$ decays. The leptoquark can accommodate the persistent tension in the…
We discuss a model with a SU$(2)_L$ doublet vector leptoquark (LQ), motivated by the recent experimental results relating to the lepton universality of $\overline{B} \to D^{(*)} \tau \overline{\nu}_\tau$. We find that scalar operators…
We study the exclusive semileptonic rare $B_c^+ \to D^+ \nu \bar{\nu}$ decay in the framework of light-cone quark model. The transition form factors $f_{+}(q^2)$ and $f_{T}(q^2)$ are evaluated in the time-like region using the analytic…
Over the past years, experiments accumulated intriguing hints for new physics (NP) in flavor observables, namely in the anomalous magnetic moment of the muon ($a_\mu$), in $R(D^{(*)})={\rm Br}(B\to D^{(*)}\tau\nu)/{\rm Br}(B\to…
We attempt to explain recent anomalies in semileptonic $B$ decays at LHCb via a composite Higgs model, in which both the Higgs and an $SU(2)_L$-triplet leptoquark arise as pseudo-Goldstone bosons of the strong dynamics. Fermion masses are…
Experimental data on $ R(D^{(*)}) $, $ R(K^{(*)}) $ and $ R(J/\psi) $, provided by different collaborations, show sizable deviations from the SM predictions. To describe these anomalies many new physics scenarios have been proposed. One of…
We show that by adding a single new scalar particle to the Standard Model, a TeV-scale leptoquark with the quantum numbers of a right-handed down quark, one can explain in a natural way three of the most striking anomalies of particle…
Leptoquarks have been suggested to solve a variety of discrepancies between the expected and observed phenomenon. In this paper, we investigate the effect of scalar leptoquarks on the lepton flavor violating B meson rare decays which…
We perform a study of the $B^{(*)}$, $D^{(*)}$ semileptonic decays, using a different method than in conventional approaches, where the matrix elements of the weak operators are evaluated and a detailed spin-angular momentum algebra is…
Recent experimental results from the LHCb, BaBar and Belle collaborations on the semitauonic decays of $B$ meson, $\bar{B}\rightarrow D^{(\ast)}\tau \bar{\nu}$, showing a significant deviation from the Standard Model (SM), hint towards a…
We examine various scenarios in which the Standard Model is extended by a light leptoquark state to explain one or both $B$-physics anomalies. Combining low-energy constraints and direct searches at the LHC, we confirm that the only single…
The persistent anomalies observed in $B$ mesons related to $b \to s \mu^+ \mu^-$ transitions point to the potential for new physics beyond the Standard Model. To explore this further, we conduct an analysis of the exclusive semileptonic…
Very compelling deviations in the recently observed lepton nonuniversality observables $\big (R_{D^{(*)}}, R_{K^{(*)}}, R_{J/\psi} \big )$ of semileptonic $B$ meson decays from their Standard Model predictions hint towards the presence of…
The semileptonic and nonleptonic decays of the b-flavor vector mesons $B^{*}_{u,d,s}$ and $B_{c}^{*}$ are investigated within the covariant light-front quark model (CLFQM). By calculating the form factors of the transitions $B_{u, d, s,…
We study the purely leptonic decay of the charged $B$-meson within the $U_1$ Vector Leptoquark model at both leading-order and with one-loop QCD corrections. The structure of this amplitude is characterised by direct quark-lepton couplings…
Most of the popular explanations of the observed anomalies in the semileptonic $B$-meson decays involve TeV scale Leptoquarks (LQs). Among the various possible LQ models, two particular LQs -- $S_{1}(3, 1, 1/3)$ and $U_{1}(3, 1, 2/3)$ seem…
In view of the emerging hints for the violation of lepton flavour universality in several $B$-meson decays, we conduct a model-independent study (effective field theory approach) of several well-motivated new physics scenarios. Taking into…
We study the scalar leptoquark effects on the rare semileptonic decays of $\Lambda_b$ baryon, governed by the quark level transition $b \to s l^+ l^-$. We estimate the branching ratios, forward-backward asymmetries, lepton polarization…
The $B$-physics experiments at LHCb, BaBar and Belle hint towards deviations from Lepton Flavor Universality in both the tree-level and loop-induced $B$ meson semileptonic decays. We propose a leptoquark model with light right-handed…
Leptoquarks (LQs) have been extensively studied in the context of $B$ anomalies. When $U(1)_{L_\mu-L_\tau}$ is introduced to a scalar LQ model with the LQ $S_1$ charged under the new symmetry, $S_1$ primarily couples to the third-generation…