Speaker
Description
We calculate the total cross section and transverse momentum distributions for the production of the enigmatic $\chi_{c1}(3872)$ (or X(3872)) (see [1]) assuming different scenarios: $c \bar c$ state and $D^{0*} {\bar D}^0 + D^0 {\bar D}^{0*}$ molecule.
The derivative of the $c \bar c$ wave function needed in the first scenario is taken from a potential $c \bar c$ model calculations. Compared to earlier calculations of molecular state, we include not only single parton scattering (SPS) but also double parton scattering (DPS) contributions. The latter one gives a smaller contribution than the SPS one.
The upper limit for the DPS production of $\chi_{c1}(3872)$ is much below the CMS data. We compare the results of our calculations with existing experimental data of CMS, ATLAS and LHCb collaborations. Reasonable cross sections can be obtained in either $c \bar c$ or molecular $D {\bar D}^*$ scenarios for $X(3872)$, provided one takes into account both directly produced $D^0, \bar D^0$, as well as $D^0, \bar D^0$ from the decay of $D^*$. However, arguments related to the lifetime of $D^*$ suggest that the latter component is not active. With these reservations, also a hybrid scenario is not excluded.
We propose to study the structure of the enigmatic $\chi_{c1}(3872)$ axial vector meson through its $\gamma^* \gamma \chi_{c1}(3872)$ transition form factor (see [2]). We derive a light-front wave function representation of the form factor for the lowest $c \bar c$ Fock-state. We found that the reduced width of the state is well within the current experimental bound recently published by the Belle collaboration. This strongly suggests a crucial role of the $c \bar c$ Fock-state in the photon-induced production. Our results for the $Q^2$ dependence can be tested by future single tagged $e^+ e^−$ experiments, giving further insights into the short-distance structure of this meson.
[1] A. Cisek, W. Schaefer and A. Szczurek,
''Structure and production mechanism of the enigmatic $X(3872)$ in high-energy hadronic reactions'',
Eur. Phys. Jour. C882, (2022) 1062.
[2] I. Babiarz, R. Pasechnik, W. Schaefer and A. Szczurek,
``Probing the structure of $\chi_{c1}(3872)$ with photon transition form factors'',
arXiv:2303.09175, Phys. Rev. D107 (2023) L071503.
| Collaboration / Activity | Theory |
|---|
