Alladi Ramakrishnan Hall

Realizing Doubly heavy Tetraquarks from lattice QCD perspective

Bhabani Sankar Tripathy

IMSc Chennai

Baryons and mesons (collectively referred to as hadrons) have been understood as quark-gluon composite states bound by Quantum ChromoDynamics (QCD), the theory of strong interactions. The conventional understanding is that baryons are made of three quarks and mesons are composed of a quark-antiquark pair. QCD also supports the existence of more complex hadrons, made of more than three quarks. Only recently have collider experiments such as those at LHCb and Belle reported these unexpected states, referred to as exotic hadrons, which are compelling candidates for such complex hadrons. The discoveries of several such exotic states, dubbed as X, Y, Z, and T_{cc}(3875) in the heavy quark flavor sector, have sparked enormous interest in the community. Understanding the binding mechanism of these exotic hadrons can play a crucial role in comprehending the non-perturbative nature of QCD dynamics. In this talk, I will discuss our recent work on lattice QCD investigations of two-meson interactions involving at least one bottom meson, relevant for heavy tetraquark channels. The computations were conducted on state-of-the-art MILC ensembles. Here, I will try to convey how hadron spectroscopy is performed in lattice QCD and the challenges we usually face.