The Baryon Isgur-Wise Function in the Large $N_c$ Limit

Abstract

In the large $N_c$ limit, the ${\Lambda }_b$ and ${\Lambda }_c$ can be treated as bound states of chiral solitons and mesons containing a heavy quark. We show that the soliton and heavy meson are bound in an attractive harmonic oscillator potential. The Isgur-Wise function for ${\Lambda }_b\to {\Lambda }_c{e}^{-}{\bar{\nu }}_e$ decay is computed in the large $N_c$ limit. Corrections to the form factor which depend on $m_N/m_Q$ can be summed exactly ($m_N$ and $m_Q$ are the nucleon and heavy quark masses). We find that this symmetry breaking correction at zero recoil is only $1\%$.

Comments: 18 pages, 0 figures, uses harvmac