Search for Prompt Production of $\chi_{c}$ and X(3872) in e^+e^- Annihilations

TL;DR

This study searched for prompt production of specific charmonium states and X(3872) in electron-positron collisions, setting upper limits on their production cross-sections that align with theoretical predictions.

Contribution

It provides the first experimental upper limits on prompt $oldsymbol{\chi_{c1,2}}$ and X(3872) production in e+e- annihilations, refining previous constraints.

Findings

No significant prompt $oldsymbol{\chi_{c1,2}}$ signals observed.

Upper limits on cross-sections are 77 fb for $oldsymbol{\chi_{c1}}$ and 79 fb for $oldsymbol{\chi_{c2}}$.

Upper limit on X(3872) prompt production established.

Abstract

We have searched for prompt production of $\chi_{c1}$, $\chi_{c2}$ and X(3872) in continuum e^+e^- annihilations using a 386 fb^{-1} data sample collected around $\sqrt{s} = 10.6$ GeV with the BABAR detector using the $\gamma J/\psi$ decay mode. After accounting for the feed-down from $\psi(2S)\to\gamma\chi_{c1,2}$, no significant signal for prompt $\chi_{c1,2}$ production is observed. We present improved upper limits on the cross-section, with the rest of the event consisting of more than two charged tracks, to be 77 fb for $\chi_{c1}$ and 79 fb for $\chi_{c2}$ with $e^+e^-$ center-of-mass frame $\chi_c$ momentum greater than 2.0 GeV at 90% confidence level. These limits are consistent with NRQCD predictions. We also set an upper limit on the prompt production of X(3872) through the decay $X(3872)\to \gamma J/\psi$.