A tetraquark or not a tetraquark: A holography inspired stringy hadron (HISH) perspective

TL;DR

This paper explores the nature of tetraquarks using a holography-inspired string model, proposing a criterion based on Regge trajectories to distinguish genuine tetraquarks from molecular states, and predicts properties of related exotic hadrons.

Contribution

It introduces a simple Regge trajectory-based criterion to identify genuine stringy tetraquarks and predicts masses and widths of their excited states across different flavors.

Findings

Predicted mass and width of higher excited Y(4630) states.

Proposed existence of Y_b and strange quark tetraquark trajectories.

Predicted Regge trajectories for various exotic resonances.

Abstract

We suggest to use the state $Y(4630)$, which decays predominantly to $\Lambda_c\bar\Lambda_c$, as a window to the landscape of tetraquarks. We propose a simple criterion to decide whether a state is a genuine stringy exotic hadron - a tetraquark - or a "molecule". If it is the former it should be on a (modified) Regge trajectory. We present the predictions of the mass and width of the higher excited states on the $Y(4630)$ trajectory. We argue that there should exist an analogous "$Y_b$" state that decays to $\Lambda_b\bar\Lambda_b$ and describe its trajectory. We conjecture also a similar trajectory for tetraquarks containing strange quarks, and the modified Regge trajectories can in fact be predicted for any resonances found decaying to a baryon-antibaryon pair. En route to the results regarding tetraquarks, we also make some additional predictions on higher excited charmonium states. We briefly discuss the zoo of exotic stringy hadrons and in particular we sketch all the possibilities of tetraquark states.