Status and Prospects of Exotic Hadrons at Belle II

Abstract

In the past 20 years, many new hadrons that are difficult to explain within the conventional quark model have been discovered in the quarkonium region; these are called exotic hadrons. The Belle II experiment, as the next-generation B factory, provides a good platform for exploring them. The charmonium-like states can be produced at Belle II in several ways, such as B meson decays, initial-state radiation processes, two-photon collisions and double charmonium production. Bottomonium-like states can be produced directly in e + e − colliding energies at Belle II with low continuum backgrounds. Belle II plans to perform a high-statistics energy scan from the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mover accent="true"> <mml:mi>B</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> threshold up to the highest possible energy of 11.24 GeV to search for new Y b states with J PC = 1 −− , X b [the bottom counterpart of χ c 1 (3872), also known as X (3872)] and partners of Z b states. We give a mini-review on the status and prospects of exotic hadrons at Belle II.