X(3872) and its production at hadron colliders

TL;DR

This paper calculates the production rates of X(3872) at hadron colliders using a NRQCD approach, showing good agreement with some experimental data and highlighting limitations of the molecular production model.

Contribution

It introduces a NRQCD-based model assuming X(3872) mainly arises from its $ ext{chi}_{c1}'$ component, providing improved predictions over molecular models.

Findings

NRQCD calculations match CMS and CDF data well

Molecular production models are inconsistent with collider data

Predicted X(3872) cross sections are larger than LHCb measurements

Abstract

We evaluate the production cross sections of $X(3872)$ at the LHC and Tevatron at NLO in $\alpha_s$ in NRQCD by assuming that the short-distance production proceeds dominantly through its $\chi_{c1}'$ component in our $\chi_{c1}'\mbox{-}D^0\bar{D}^{*0}$ mixing model for $X(3872)$. The outcomes of the fits to the CMS $p_T$ distribution can well account for the recent ATLAS data in a much larger range of transverse momenta ($10~\mbox{GeV}<p_T<70~\mbox{GeV}$), and the CDF total cross section data, and are also consistent with the value of $k=Z_{c\bar c}\cdot Br(X\to J/\psi\pi^+\pi^-)$ constrained by the $B$-meson decay data. %It can also well describe the behavior of the CDF $\psi(2S)$ data, which show a strong %resemblance to that of the X(3872). For LHCb the predicted X(3872) total cross section is larger than the data by a factor of 2, which is due to the problem of the fixed-order NRQCD calculation that may not be applicable for the region with small $p_T$ ($p_T\sim 5 ~\mbox{GeV}$) and large forward rapidity $(2.5<y<4.5)$. In comparison, the prediction of molecule production mechanism for $X(3872)$ is inconsistent with both $p_T$ distributions and total cross sections of CMS and ATLAS, and the total cross section of CDF.