Related papers: $b \to c$ semileptonic sum rule: Extension to angu…
We present results of global fits of all relevant experimental data on rare $b \to s$ decays. We observe significant tensions between the Standard Model predictions and the data. After critically reviewing the possible sources of…
In top-pair events where at least one of the tops decays semi-leptonically, the identification of the lepton charge allows to tag not only the top charge but also that of the subsequent b quark. In cases where the b also decays…
In the Standard Model of particle physics, charged leptons of different flavour couple to the electroweak force carriers with the same interaction strength. This property, known as lepton flavour universality, was found to be consistent…
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…
The Standard Model (SM) predicts the universality of lepton couplings with the electroweak gauge bosons. Semileptonic decays of $b$-hadrons provide a powerful framework for testing the SM and probing possible New Physics effects. In…
We study the heavy quark effective theory prediction for semileptonic $B$ decays into an orbital excited $F$-wave charmed doublet, the ($2^{+}$, $3^{+}$) states ($D^{*'}_{2}$, $D_{3}$), at the leading order of heavy quark expansion. The…
Mass and full width of the heavy scalar molecule $\mathcal{M}$ composed of the mesons $B_{c}^{+}$ and $B_{c}^{-}$ are calculated in the QCD sum rule framework. To find its mass and current coupling, we apply the two-point sum rule method.…
We consider the recent LHCb result for $B_c\to J/\psi \tau \nu$ in conjunction with the existing anomalies in $R(D)$ and $R(D^\star)$ within the framework of a right-handed current with enhanced couplings to the third generation. The model…
We use QCD sum rules to calculate the hadronic matrix elements governing the rare decays $B \to K \ell^+ \ell^-$ and $B \to K^* \ell^+ \ell^-$ induced by the flavour changing neutral current $b \to s$ transition. We also study relations…
We study semileptonic $B$ meson decays $B^+ \to D_1^{(\prime)}\ell^+\nu_\ell$ and $B_s^0 \to D_{s1}^{-(\prime)}\ell^+\nu_\ell$, where $\ell=\mu,\tau$. The final state axial vector mesons are treated as mixtures of the heavy quark basis…
In these lectures, I present several important applications of QCD sum rules to the decay processes involving heavy-flavour hadrons. The first lecture is introductory. As a study case, the sum rules for decay constants of the heavy-light…
The measurement of lepton universality parameters $R_{K^{(*)}}$ was updated by LHCb in December 2022, which indicated that the well-known anomalies in flavor-changing neutral current (FCNC) processes of B meson decays have faded away.…
Precise theoretical predictions derived from the Standard Model are a key ingredient in searches for new physics in the flavor sector. The large mass and long lifetime of the $b$ quark make processes involving $b$ quarks of particular…
We conduct an investigation on the spin $\frac{3}{2}\rightarrow \frac{1}{2}$ semileptonic weak transition of single heavy baryons for the exclusive decay $\Sigma_{b}^{*0}\,\rightarrow\, \Sigma_{c}^{+}\,\ell\,\bar{\nu}_{\ell}$ in three…
Hints of lepton flavor universality violation observed in various flavor ratios such as $R_D$, $R_{D^*}$, $R_{J/\psi}$, $P_\tau^{D^*}$ and $F_L^{D^*}$ in $B\to D^{(*)}\,\ell \, \nu$ and $B_c\to J/\psi \, \ell\, \nu$ charge current decays…
We analyze the semileptonic rare decays of $B$ meson to $K_{1} (1270)$ and $K_{1} (1400)$ axial vector mesons. The $B\to K_{1} (1270,1400) \ell^+ \ell^-$ decays are significant flavor changing neutral current decays of the $B$ meson. These…
Recently hints of lepton flavor non-universality emerged when the BaBar Collaboration observed deviations from the standard model predictions in $R(D^{(*)}) \equiv {\cal B}({\bar B} \to D^{(*)+} \tau^- {\bar\nu}_\tau) / {\cal B}({\bar B}…
There are discrepancies between the experimental results and the Standard Model predictions, in the lepton flavor universality of the semileptonic $B$ decays: $B \to D^{(*)} \ell \nu$. As the new physics interpretations, new charged vector…
This is an addendum to the previous publication, P. Ko and J.-h. Park, Phys. Rev. D80, 035019 (2009). The semileptonic charge asymmetry in B_s decays is discussed in the context of general MSSM with gluino-mediated flavor and CP violation…
The anomalously large like-sign dimuon charge asymmetry in semileptonic b-hadron decays recently measured by the D0 Collaboration may be hinting at the presence of CP-violating new physics in the mixing of B_s mesons. It has been suggested…