Production of X(3872) at PANDA

TL;DR

This paper predicts the production rates and line-shapes of X(3872) at PANDA, aiming to distinguish its molecular or charmonium nature through threshold measurements and decay analysis.

Contribution

It provides numerical predictions for X(3872) production near threshold in antiproton-proton collisions, considering two interpretations and analyzing their distinguishability.

Findings

High event rates near threshold (10^6 to 10^8) at PANDA.

More than 60% of events originate from X(3872) decay.

Line-shape analysis can differentiate between interpretations.

Abstract

The recently discovered $X$(3872) has many possible interpretations. We study the production of $X$(3872) with PANDA at GSI for the antiproton-proton collision with two possible interpretations of X(3872). One is as a loosely-bound molecule of $D$-mesons, while another is a 2P charmonium state $\chi_{c1}$ (2P). Using effective couplings we are able to give numerical predictions for the production near the threshold and the production associated with $\pi^0$. The produced $X$(3872) can be identified with its decay $J/\psi \pi^+\pi^-$. We also study the possible background near the threshold production for $X(3872) \to J/\psi \pi^+\pi^-$. With the designed luminosity $1.5{\rm fb}^{-1}$ per year of PANDA we find that the event number of $p\bar p \to J/\psi \pi^+\pi^-$ near the threshold is at the order of $10^6 \sim 10^8$, where the large uncertainty comes from the total decay width of X(3872). Our study shows that at the threshold more than about 60% events come from the decay of X(3872) and two interpretations are distinguishable from the line-shape of the production. With our results we except that the PANDA experiments will shed light on the property of X(3872).