Fully charmed tetraquark production at the LHC experiments
I. Belov, Alessandro Giachino, E. Santopinto
Abstract
A bstract We develop the formalism for production of a fully heavy tetraquark and apply it to the calculation of pp → T 4 c + X cross-sections. We demonstrate that the production cross-section of a fully heavy tetraquark, even if it is a diquark-antidiquark cluster, can be obtained in the meson-like basis, for which the spin-color projection technique is well established. Prompted by the recent LHCb, ATLAS and CMS data, we perform a pQCD calculation of $$ \mathcal{O} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( $$ {\alpha}_s^5 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>α</mml:mi> <mml:mi>s</mml:mi> <mml:mn>5</mml:mn> </mml:msubsup> </mml:math> ) short-distance factors in the dominant channel of gluon fusion, and match these to the four-body T 4 c wave functions in order to obtain the unpolarized T 4 c (0 ++ , 1 + − , 2 ++ ) cross-sections. The novelty in comparison with the recently published article [1] lies in the fact that we predict the absolute values as well as the dσ/dp T spectra in the kinematic ranges accessible at the ongoing LHC experiments. From the comparison with the signal yield at LHCb we derive the constraints on the Φ · Br( J/ψ J/ψ ) (reduced wave function times branching) product for the T 4 c candidates for X (6900) and observe that X (6900) is compatible with a 2 ++ (2 S ) state.