An Estimate of the Partial Width for X(3872) into p p-bar

TL;DR

This paper estimates the decay width of the X(3872) particle into proton-antiproton pairs, assuming it is a weakly-bound hadronic molecule, and relates it to known cross sections near the threshold.

Contribution

It provides a novel estimate of the X(3872) partial width into p p-bar based on molecular structure assumptions and cross section scaling from known processes.

Findings

The partial width is proportional to the square root of the binding energy.

Estimated partial width is comparable to that of chi_{c1}.

The approach links decay width to threshold cross section extrapolation.

Abstract

We present an estimate of the partial width of X(3872) into p p-bar under the assumption that it is a weakly-bound hadronic molecule whose constituents are a superposition of the charm mesons D^{*0} D-bar^0 and D^{0} D-bar^{*0}. The p p-bar partial width of X is therefore related to the cross section for p p-bar to D^{*0} D-bar^0 near the threshold. That cross section at an energy well above the threshold is estimated by scaling the measured cross section for p p-bar to K^{*-} K^+. It is extrapolated to the D^{*0} D-bar^0 threshold by taking into account the threshold resonance in the 1^{++} channel. The resulting prediction for the p p-bar partial width of X(3872) is proportional to the square root of its binding energy. For the current central value of the binding energy, the estimated partial width into p p-bar is comparable to that of the P-wave charmonium state chi_{c1}.