Production of $X(3872)$ at High Multiplicity
ORAL
Abstract
The dependence of the production of the $X(3872)$ meson on the hadron multiplicity in $pp$ collisions has been used as evidence against $X$ being a charm-meson molecule. The argument is based in part on the incorrect assumption that the cross section for the breakup of $X$ by scattering with comovers can be approximated by a geometric cross section inversely proportional to the binding energy of $X$. The breakup cross section should instead be approximated by the probability-weighted sum of the cross sections for the scattering of comoving pions from the charm-meson constituents of $X$, which is insensitive to the binding energy. A simple modification of the comover interaction model gives excellent fits to the data from the LHCb collaboration on the multiplicity dependence of the production of $X$ and $\psi(2S)$ using parameters compatible with $X$ being a loosely bound charm-meson molecule.
*This work was supported in part by the U.S. Department of Energy under grant DE-SC0011726, the National Natural Science Foundation of China under grant 11905112, and the Natural Science Foundation of Shandong Province under grant ZR2019QA012. We acknowledge useful communications with A. Esposito and A. Pilloni.
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