Strong Decays of Charmed Baryons in Heavy Hadron Chiral Perturbation Theory: An Update

TL;DR

This paper updates the coupling constants in heavy hadron chiral perturbation theory for charmed baryons using recent experimental data, providing refined insights into their decay processes and structure.

Contribution

It offers new determinations of key coupling constants in heavy hadron chiral perturbation theory based on recent measurements, improving understanding of charmed baryon decays and structure.

Findings

Updated coupling constant g_2=0.565^{+0.011}_{-0.024}

Extracted h_2=0.63±0.07 from Λ_c(2595)^+ decays

Identified tension in h_2 value affecting decay rate predictions

Abstract

We first give a brief overview of the charmed baryon spectroscopy and discuss their possible structure and spin-parity assignments in the quark model. With the new Belle measurement of the widths of $\Sigma_c(2455)$ and $\Sigma_c(2520)$ and the recent CDF measurement of the strong decays of $\Lambda_c(2595)$ and $\Lambda_c(2625)$, we give updated coupling constants in heavy hadron chiral perturbation theory. We find $g_2=0.565^{+0.011}_{-0.024}$ for $P$-wave transitions between $s$-wave and $s$-wave baryons, and $h_2$, one of the couplings responsible for $S$-wave transitions between $s$-wave and $p$-wave baryons, is extracted from $\Lambda_c(2595)^+\to\Lambda_c^+\pi\pi$ to be $0.63\pm0.07$. It is substantially enhanced compared to the old value of order 0.437. With the help from the quark model, two of the couplings $h_{10}$ and $h_{11}$ responsible for $D$-wave transitions between $s$-wave and $p$-wave baryons are determined from $\Sigma_c(2880)$ decays. There is a tension for the coupling $h_2$ as its value extracted from $\Lambda_c(2595)^+\to \Lambda_c^+\pi\pi$ will imply $\Xi_c(2790)^0\to\Xi'_c\pi$ and $\Xi_c(2815)^+\to\Xi_c^*\pi$ rates slightly above the current limits. It is conceivable that SU(3) flavor symmetry breaking can help account for the discrepancy.