Is the X(3915) the chi_{c0}(2P)?

TL;DR

This paper critically examines whether the X(3915) meson can be identified as the chi_{c0}(2P) charmonium state, using decay rate measurements and branching fraction limits, and finds significant inconsistencies with this assignment.

Contribution

It provides a detailed analysis showing that the decay patterns and measured signals of X(3915) are incompatible with it being the chi_{c0}(2P) state, challenging previous assignments.

Findings

Measured gamma-gamma->X(3915) signal implies Bf(chi_{c0}(2P)->omega J/psi)<7.8%

Limits on Bf(X(3915)->D0 D0-bar) are inconsistent with expectations for chi_{c0}(2P)

Absence of D0 D0-bar decay signals contradicts the charmonium interpretation

Abstract

The Particle Data Group has assigned the X(3915) meson, an omega J/psi mass peak seen in B-> omega J/psi decays and in two-photon fusion reactions gamma-gamma->omega J/psi, as the chi_{c0}(2P), the 2^3P_0 charmonium state. Here it is shown that if the X(3915) is the chi_{c0}(2P), the measured strength of the gamma-gamma->X(3915) signal implies an upper limit on the branching fraction Bf(chi_{c0}(2P)->omega J/psi)<7.8% that conflicts with a >14.3% lower limit derived for the same quantity from the B-> K X(3915) decay rate. Also, the absence any signal for X(3915)-> D0 D0-bar in B+ -> K+ D0 D0-bar decays is used to establish the limit Bf(X(3915)->D0 D0-bar) < 1.2xBf(X(3915)->omega J/psi). This contradicts expectations that chi_{c0}(2P) decays to D0 D0-bar would be a dominant process, while decays to omega J/psi, which are Okubo-Zweig-Iizuka suppressed, would be relatively rare. These, plus reasons given earlier by Guo and Meissner, raise serious doubts about the X(3915)=chi_{c0}(2P) assignment.