Bottom Tetraquark Production at RHIC?

Background: A resonance has been observed by the ANDY Collaboration at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory in Cu+Au collisions at center-of-mass energy $sqrt{s} = 200$ GeV and at forward rapidity with an average mass of 18.15 GeV. The Collaboration suggests that it is a $b overline b b overline b$ tetraquark state decaying to two $Upsilon$(1S) states, each measured through the $Upsilon rightarrow ggg$ channel. Purpose: Their suggestion is investigated assuming that the two $Upsilon$ states are produced through the materialization of a $|uud boverline b b overline b rangle$ Fock state in the projectile. Methods: The $Upsilon$ pair mass and rapidity distributions arising from such a state are calculated. The production of an $X_b(b overline b b overline b)$ tetraquark state from the same Fock configuration is also investigated. The dependence on bottom quark mass and their transverse momentum range is also studied. Results: It is found that double $Upsilon$ production from these $|uud b overline b b overline b rangle$ states peak in the rapidity range of the ANDY detector. The $Upsilon$ pair and $X_b$ masses are, however, higher than the mass reported by the ANDY Collaboration. Conclusions: The results obtained from these calculations are incompatible with the ANDY result. They are, however, compatible with previous predictions of $b overline b b overline b$ tetraquark masses.