Properties of the X(3872) at Belle

TL;DR

This paper investigates the properties of the X(3872) particle produced in B+ decays, providing evidence supporting its interpretation as a D D*-bar bound state and constraining its charmonium assignments.

Contribution

It presents new experimental results on X(3872) decays and offers insights into its structure, supporting the molecular state hypothesis over charmonium models.

Findings

X(3872) decays involve virtual omega mesons

Supports D D*-bar bound state interpretation

Constraints on charmonium state assignments

Abstract

We report recent results on the properties of the X(3872) produced via the B+ --> K+ X(3872) decay process. We observe X -->pi+pi-pi0 J/psi decays where the 3pi invariant masses cluster near the upper kinematic boundary suggesting that they originate from sub-threshold decays to virtual omega(782) mesons. This is consistent with expectations for a DD*-bar bound state interpretation for the X(3872). In addition, we constrain the possible charmonium-state assignments for this particles. Results are obtained from a 253/fb data sample that contains 274 million BB-barr pairs that was collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider.