Title: Charm-meson triangle singularity in $e^{+}{e}^{-}$ annihilation into $D^{*0}{\overline{D}}^0+\gamma$

Abstract

We calculate the cross section for $e^+ e^-$ annihilation into $$D^{*0} \bar D^0 +\gamma$$ at center-of-mass energies near the $$D^{*0} \bar D^{*0}$$ threshold under the assumption that $X(3872)$ is a weakly bound charm meson molecule. The Dalitz plot has a $$\bar D^{*0}$$ resonance band in the squared invariant mass $$t$$ of $$\bar D^0 \gamma$$. In the limit as the decay width of the $$D^{*0}$$ goes to 0, the Dalitz plot also has a narrow band in the squared invariant mass $$u$$ of $$D^{*0} \bar D^0$$ from a charm-meson triangle singularity. At the physical value of the $$D^{*0}$$ width, the narrow band reduces to a shoulder. Thus the triangle singularity cannot be observed directly as a peak in a differential cross section as a function of $$u$$. It may however be observed indirectly as a local minimum in the $$t$$ distribution for events with $$u$$ below the triangle singularity. The minimum is produced by the Schmid cancellation between triangle loop diagrams and a tree diagram. The observation of this minimum would support the identification of $X(3872)$ as a weakly bound charm meson molecule.

Authors:

Braaten, Eric; He, Li-Ping; Ingles, Kevin ;

• Search DOE PAGES for author "Ingles, Kevin"
• Search DOE PAGES for ORCID "0000-0002-5369-0493"

Jiang, Jun

• Search DOE PAGES for author "Jiang, Jun"
• Search DOE PAGES for ORCID "0000-0002-0718-4813"

Publication Date:

Thu May 28 00:00:00 EDT 2020

Research Org.:

The Ohio State Univ., Columbus, OH (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP); Natural Science Foundation of Shandong Province; Fundamental Research Funds of Shandong University

OSTI Identifier:

1631077

Alternate Identifier(s):

OSTI ID: 1782849

Grant/Contract Number:  

SC0011726; ZR2019QA012

Resource Type:

Published Article

Journal Name:

Physical Review D

Additional Journal Information:

Journal Name: Physical Review D Journal Volume: 101 Journal Issue: 9; Journal ID: ISSN 2470-0010

Publisher:

American Physical Society

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS