Observation of the Narrow State $X(3872)\to J/\psi\pi^{+}\pi^{-}$ in $\bar{p}p$ Collisions at $\sqrt{s}=1.96 \TeV$

TL;DR

This paper reports the first observation of the X(3872) state in proton-antiproton collisions, confirming its existence and measuring its mass with high precision, consistent with previous experiments.

Contribution

The study provides the first observation of the X(3872) in $ar{p}p$ collisions and measures its mass accurately, supporting its identification as a new narrow meson state.

Findings

Observed 730 ± 90 decays of X(3872)

Measured mass at 3871.3 ± 0.7 (stat) ± 0.4 (syst) MeV/c²

Confirmed the X(3872) state in $ar{p}p$ collisions

Abstract

We report the observation of a narrow state decaying into $J/\psi\pi^+\pi^-$ and produced in $220 pb^{-1}$ of $\bar{p} p $ collisions at $\sqrt{s}=1.96 TeV$ in the CDF II experiment. We observe $ 730 \pm 90 $ decays. The mass is measured to be $3871.3 \pm 0.7 (stat) \pm 0.4 (syst) MeV/c2$, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the X(3872) meson.