Properties of Exotic Charmonium-like States at CDF

TL;DR

This paper presents evidence for a new narrow exotic state Y(4140) decaying to J/psi phi, and provides a precise measurement of the X(3872) mass, contributing to understanding of charmonium-like states.

Contribution

First evidence for the Y(4140) state decaying to J/psi phi and a precise measurement of the X(3872) mass using the largest available data samples.

Findings

Evidence for Y(4140) as a narrow structure above open charm threshold

Most precise measurement of the X(3872) mass to date

X(3872) consistent with a single state

Abstract

We report the recent evidence for a new narrow structure, Y(4140), decaying to the $J/\psi \phi$ final state, in exclusive $B^+\to J/\psi\phi K^+$ decays in a data sample corresponding to an integrated luminosity of 2.7 \ifb collected at the CDF II detector. This narrow structure with its mass well above open charm pairs is unlikely to be a candidate for a conventional charmonium state. From a study of the X(3872) mass and width based on the world's largest sample of $X(3872)\to J/\psi\pi^+\pi^-$ decays, we find that our X(3872) signal is consistent with a single state, and leads to the most precise measurement of the X(3872) mass.