${\Lambda }_b\to {\Sigma }_c^{(\ast )}\pi l\bar{\nu }$ in the heavy quark, chiral, and large $N_c$ limits

Abstract

The decay of ${\Lambda }_b\to {\Sigma }_c^{(\ast )}\pi l\bar{\nu }$ processes are calculated in the framework of heavy baryon chiral perturbation theory with help of the $1/N_c$ expansion. The decay rate distributions over $v\cdot v^{\prime }$ where $v$ and $v^{\prime }$ are the 4-vector velocities of ${\Lambda }_b$ and ${\Sigma }_c^{(\ast )}$ respectively, and over the pion and lepton energies are given. The decay branching ratios amount to about $1.21(0.971)$ for ${\Lambda }_b\to {\Sigma }_c\pi l\bar{\nu }$ and $0.798(0.640)$ for ${\Lambda }_b\to {\Sigma }_c^{\ast }\pi l\bar{\nu }$ by using the baryonic Isgur-Wise function predicted by QCD sum rule (large $N_c$ QCD).

Comments: 17 pages, 8 figures, to appear in PRD