Overview of the status/results in the exotics sector

Chengping Shen,Changsheng Li,A Wrońska,C Guaraldo,A Magiera,H Ströher

doi:10.1051/epjconf/201613001004

Abstract

Many exotic hadronic states beyond the conventional quark model (called char-moniumlike/bottomoniumlike states or XYZ particles) were found in the B -factories or energy scans of the cross sections of e + e − annhilation into conventional quarkonia and light hadrons. Their nature properties were proposed including glueballs, hybrids, multi-quark states, hadron molecules, etc. Dramatic progress was made in the study of the them after the running of the B -factories. In this report, I present the most recent results on the XYZ results from Belle experiment.

Highlights

During the past thirteen years many exotic states decaying into conventional quarkonia and light hadrons, the so-called “XYZ" particles, have been reported in many different reactions [1]
They correspond to high excitations and have masses above the DDor BBthresholds
After the charged charmoniumlike state Zc(3900) was observed by BESIII and Belle experiments [14, 22] BESIII and Belle observed a series of charged Zc states including Zc(4020) [19], Zc(4200) [23], and Zc(3885) [24]

Summary

Introduction

During the past thirteen years many exotic states decaying into conventional quarkonia and light hadrons, the so-called “XYZ" particles, have been reported in many different reactions [1]. They correspond to high excitations and have masses above the DDor BBthresholds. Most cannot be described well by quarkonium potential models [1,2,3] Their unusual properties have stimulated considerable theoretical interest and various interpretations have been proposed, including tetraquarks, molecules, hybrids, or hadrocharmonia [1, 3, 4]. I present the most recent results on the study of the XYZ states from the Belle experiment

The X states

The Y states

The Z states