Exotic hadron spectroscopy at the LHCb experiment

TL;DR

This paper reviews LHCb's recent findings in exotic hadron spectroscopy, including the discovery of pentaquark states and the non-confirmation of a tetraquark candidate, advancing understanding of heavy hadron structures.

Contribution

It provides the first observation of pentaquark states at LHCb and clarifies the existence of a proposed tetraquark candidate, contributing novel experimental insights.

Findings

Discovery of pentaquark states in $\Lambda_b^0 o J/ ext{ extbackslash}psi p K^-$ decays

Non-confirmation of the D0 tetraquark candidate in $B_s^0 ext{ extbackslash}pi^+$ spectrum

Precise measurements of masses, widths, and quantum numbers of exotic states

Abstract

The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from proton-proton collisions at the CERN Large Hadron Collider. During Run 1, it has recorded the world's largest data sample of beauty and charm hadrons, enabling precise studies into the spectroscopy of such particles, including discoveries of new states and measurements of their masses, widths and quantum numbers. An overview of recent LHCb results in the area of exotic hadron spectroscopy is presented, focussing on the discovery of the first pentaquark states in the $\Lambda_b^0 \to J/\psi p K^-$ channel and a search for them in the related $\Lambda_b^0 \to J/\psi p\pi^-$ mode. The LHCb non-confirmation of the D0 tetraquark candidate in the $B_s^0\pi^+$ invariant mass spectrum is presented.