First measurement of the Q^2 distribution of X(3915) single-tag two-photon production

Abstract

We report the first measurement of the $Q^2$ distribution of $X(3915)$ produced by single-tag two-photon interactions. The decay mode used is $X(3915)\to J/\ddot{I}ˆ\ddot{I}‰$. The covered $Q^2$ region is from 1.5 (GeV/$c$)${}^2$ to 10.0 (GeV/$c$)${}^2$. We observe $7.9\pm 3.1(stat.)\pm 1.5(syst.)$ events, where we expect $4.1\pm 0.7$ events based on the $Q^2=0$ result from the no-tag two-photon process, extrapolated to higher $Q^2$ region using the $c\bar{c}$ model of Schuler, Berends, and van Gulik. The shape of the distribution is also consistent with this model; we note that statistical uncertainties are large.

10 pages, 9 figures, 3 tables