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Avijit Hazra

Publications and source records attributed to Avijit Hazra.

4 recordsLinked to original sources

Weak decays of $\pmb{B_c}$ involving vector mesons in self-consistent covariant light-front approach

We present a comprehensive analysis of weak transition form factors, semileptonic decays, and nonleptonic decays of $B_c$ meson involving pseudoscalar ($P$) and vector ($V$) meson for bottom-conserving and bottom-changing decay modes. We employ self-consistent covariant light-front quark model (CLFQM), termed as Type-II correspondence, to calculate the $B_c$ to $P(V)$ transition form factors. The Type-II correspondence in the CLF approach gives self-consistent results associated with the $B^{(i)}_j$ functions, which vanish numerically after the replacement $M^{\prime(\prime\prime)} \to M_0^{\prime(\prime\prime)}$ in traditional Type-I correspondence, and the covariance of the matrix elements is also restored. We investigate these effects on bottom-conserving $B_c$ to $P(V)$ form factors that have not yet been studied in CLFQM Type-II correspondence. In addition, we quantify the implications of self-consistency propagating to weak decays involving both bottom-conserving and bottom-changing $B_c$ transition form factors. We use two different parameterizations, the usual three-parameter function of $q^2$ and the model-independent $z$-series expansion, to establish a clear understanding of $q^2$ dependence. Using the numerical values of the form factors, we predict the branching ratios and other physical observables, such as forward-backward asymmetries, polarization fractions, etc., of the semileptonic $B_c$ decays. Subsequently, we predict the branching ratios of two-body nonleptonic weak decays using the factorization hypothesis in self-consistent CLFQM. We also compare our results with those of other theoretical studies.

hep-ph

$B_c$ to $A$ Transition Form Factors and Semileptonic Decays in Self-consistent Covariant Light-front Approach

We present a comprehensive analysis of the semileptonic weak decays of $B_c$ meson decaying to axial-vector ($A$) mesons for bottom-conserving and bottom-changing decay modes. We employ self-consistent covariant light-front quark model (CLFQM) that uses type-II correspondence to eliminate inconsistencies in the traditional type-I CLFQM. As a fresh attempt, we test the self-consistency in CLFQM through type-II correspondence for $B_c \to A$ meson transition form factors. We establish that in type-II correspondence the form factors for longitudinal and transverse polarization states are numerically equal and are free from zero-mode contributions, which confirms the self-consistency of type-II correspondence for $B_c \to A$ transition form factors. Furthermore, we ascertain that the problems of inconsistency and violation of covariance of CLFQM within the type-I correspondence are resolved in type-II correspondence for $B_c \to A$ transitions. We thoroughly investigate the effects of self-consistency between type-I and type-II schemes using a comparative analysis. We also study the $q^2$ dependence of the form factors in weak hadronic currents for the whole accessible kinematic range $0 \leqslant q^2 \leqslant q^2_{max}$ for both bottom-conserving as well as bottom-changing transitions. In addition, we extend our analysis to predict the branching ratios of the semileptonic weak decays of $B_c$ meson involving axial-vector meson in the final state to quantify the effects of self-consistency in these decays that were not studied before. We evaluate the lepton mass effect on these branching ratios and various other important physical observables, such as forward-backward asymmetries, lepton-side convexity parameter, asymmetry parameter, and longitudinal polarization asymmetries and fractions. Finally, we obtain the lepton flavor universality ratios for various decays.

hep-ph

Screening of quark charge and mixing effects on transition moments and M1 decay widths of baryons

Motivated by the precision measurements of heavy flavor baryon masses, we analyze the modification of quark charge by employing the screening effect inside the baryon. In addition, we calculate the isospin mass splitting up to charmed baryons employing isospin symmetry breaking. Consequently, we obtain the masses, magnetic moments, and transition moments of $J^P=\frac{1}{2}^+$ and $\frac{3}{2}^+$ baryons to predict radiative decay widths for $\frac{1}{2}^{\prime +} \to \frac{1}{2}^+$ and $\frac{3}{2}^+\to \frac{1}{2}^{(\prime)+}$ transitions. Finally, we include the effects of state mixing in flavor degenerate baryon magnetic and transition moments, as well as M1 transition decay widths.

hep-ph

Radiative M1 transitions of heavy baryons: Effective Quark Mass Scheme

We calculate the magnetic moments of ground state $J^P=\frac{1}{2}^+$ and $J^P=\frac{3}{2}^+$ heavy flavor charm and bottom baryon states employing the concept of effective mass based on single gluon exchange interaction coupling to the spectator quarks in the non-relativistic quark model. We exploit the current experimental information in the heavy flavor sector to estimate the interaction contributions to get the effective masses of the quarks inside the baryons. We study the spin $\frac{1}{2}^{'+} \rightarrow \frac{1}{2}^+$, $\frac{3}{2}^+ \rightarrow \frac{1}{2}^+$, and $\frac{3}{2}^+ \rightarrow \frac{1}{2}^{'+}$ transition moments for these baryons. We make robust predictions of the radiative M1 decay widths of singly, doubly, and triply heavy flavored baryons.

hep-ph