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

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}.