Nonrelativistic effective field theory for heavy exotic hadrons

Abstract

We propose an effective field theory to describe hadrons with two heavy quarks without any assumption on the typical distance between the heavy quarks with respect to the typical hadronic scale. The construction is based on Non-Relativistic QCD and inspired in the strong coupling regime of Potential Non-Relativistic QCD. We construct the effective theory at leading and next-to-leading order in the inverse heavy-quark mass expansion for arbitrary quantum numbers of the light degrees of freedom. Hence our results hold for hybrids, tetraquarks, double heavy baryons and pentaquarks, for which we also present the corresponding operators at Non-Relativistic level. At leading order, the effective theory enjoys heavy quark spin symmetry and corresponds to the Born-Oppenheimer approximation. At next-to-leading order, spin and velocity dependent terms arise, which produce splittings in the heavy-quark spin symmetry multiplets. A concrete application to double heavy baryons is presented in an accompanying paper.

Masses of Doubly Heavy Tetraquarks with Error Bars

“…A new nonrelativistic effective field theory for doubly heavy hadrons beyond the compact heavy-diquark limit was recently developed by Soto and Tarrús Castellà [45] and applied to doubly heavy baryons [46]. At leading order in the 1/m Q expansion, the Lagrangian has heavy quark spin symmetry and corresponds to the Born-Oppenheimer approximation.…”

“…That assumption is avoided in the effective field theory for doubly heavy hadrons developed in Refs. [45,46], which makes use of lattice QCD calculations of Born-Oppenheimer potentials. Such an effective field theory, along with the discovery of more doubly heavy hadrons in future experiments, should eventually provide a complete picture of the spectrum of doubly heavy tetraquarks.…”

Hadron Spectroscopy with Lattice QCD

“…states that have been experimentally discovered in the charmonium-like sector. Some general analytic considerations are provided in [105][106][107]. A number of future improvements are necessary to study such closed-bottom states beyond the simplifications used in [102][103][104].…”

Tetraquark Masses by using extension of Gursey-Radicati Mass Formula

“…Also, with the observation of a Y(4220) resonance in the process e + e − → π 0 Z c (3900) 0 [24]. Many theoretical approaches are proposed such as Born-Oppenheimer approximation [25], compact tetraquark model [26], Spectroscopy of pentaquark states [27], diquark-antidiquark model [28], compact pentaquark structures [29], hadrocharmonium model [30], heavy quark spin symmetry and chiral effective field theory are employed to study these tetraquark and pentaquark states [31]. In the past decade, many hidden charm and bottom tetraquark states have been studied by different models and theories for their masses, decay widths and branching ratio's etc.…”