The X(3872) at CDF II

TL;DR

This paper reports the measurement of the X(3872) meson's mass and its production sources in proton-antiproton collisions at CDF II, confirming its existence and analyzing its origin.

Contribution

The study provides the first detailed measurement of the X(3872) mass and quantifies its production from prompt sources and b-hadron decays at CDF II.

Findings

X(3872) mass measured as 3871.3 MeV/c2

Approximately 16% of X(3872) originate from b-hadron decays

Production source distribution similar to psi(2S) state

Abstract

Last year's X(3872) discovery was confirmed with the CDF II detector in pbarp collisions. We measure its mass to be $3871.3 \pm 0.7 \pm 0.4 MeV/c2$. The source of X-mesons in the large CDF sample is resolved by studying their vertex displacement. We find $16.1 \pm 4.9 \pm 2.0$% of our X-sample comes from decays of b-hadrons, and the remainder from prompt sources: either direct production or by decay of (unknown) short-lived particles. The mix of production sources is similar to that observed for the psi(2S) charmonium state.