Title: Deciphering the mechanism of near-threshold $$$$J/\psi $$$$ photoproduction

Abstract

Abstract The photoproduction of the $$$$J/\psi $$$$ $J/\psi$ off the proton is believed to deepen our understanding of various physics issues. On the one hand, it is proposed to provide access to the origin of the proton mass, based on the QCD multipole expansion. On the other hand, it can be employed in a study of pentaquark states. The process is usually assumed to proceed through vector-meson dominance, that is the photon couples to a $$$$J/\psi $$$$ $J/\psi$ which rescatters with the proton to give the $$$$J/\psi p$$$$ $J/\psi p$ final state. In this paper, we provide a compelling hint for and propose measurements necessary to confirm a novel production mechanism via the $$$$\varLambda _c \bar{D}^{(*)}$$$$ ${\Lambda }_c{\overline{D}}^{(\ast )}$ intermediate states. In particular, there must be cusp structures at the $$$$\varLambda _c \bar{D}^{(*)}$$$$ ${\Lambda }_c{\overline{D}}^{(\ast )}$ thresholds in the energy dependence of the $$$$J/\psi $$$$ $J/\psi$ photoproduction cross section. The same mechanism also implies the $$$$J/\psi $$$$ $J/\psi$ -nucleon scattering lengths of order 1 mfm. Given this, one expects only a minor contribution of charm quarks to the nucleon mass.

Authors:

Du, Meng-Lin ;

• Search DOE PAGES for author "Du, Meng-Lin"
• Search DOE PAGES for ORCID "0000-0002-7504-3107"

Baru, Vadim ;

• Search DOE PAGES for author "Baru, Vadim"
• Search DOE PAGES for ORCID "0000-0001-6472-1008"

Guo, Feng-Kun ;

• Search DOE PAGES for author "Guo, Feng-Kun"
• Search DOE PAGES for ORCID "0000-0002-2919-2064"

Hanhart, Christoph ;

• Search DOE PAGES for author "Hanhart, Christoph"
• Search DOE PAGES for ORCID "0000-0002-3509-2473"

Meißner, Ulf-G. ;

• Search DOE PAGES for author "Meißner, Ulf-G."
• Search DOE PAGES for ORCID "0000-0003-1254-442X"

Nefediev, Alexey ;

• Search DOE PAGES for author "Nefediev, Alexey"
• Search DOE PAGES for ORCID "0000-0002-9988-9430"

Strakovsky, Igor

• Search DOE PAGES for author "Strakovsky, Igor"
• Search DOE PAGES for ORCID "0000-0001-8586-9482"

Publication Date:

Mon Nov 16 00:00:00 EST 2020

Research Org.:

George Washington Univ., Washington, DC (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Nuclear Physics (NP); National Natural Science Foundation of China (NSFC); Russian Science Foundation

OSTI Identifier:

1714391

Alternate Identifier(s):

OSTI ID: 1726236

Grant/Contract Number:  

SC0016583; 18-12-00226; XDB34030303; QYZDB-SSW-SYS013; 11835015; 11947302; 11961141012

Resource Type:

Published Article

Journal Name:

European Physical Journal. C, Particles and Fields

Additional Journal Information:

Journal Name: European Physical Journal. C, Particles and Fields Journal Volume: 80 Journal Issue: 11; Journal ID: ISSN 1434-6044

Publisher:

Springer

Country of Publication:

Germany

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS