ρ-Meson Nucleon Scattering Length from CLAS Threshold Photoproduction Measurementsmission
ORAL
Abstract
Extending our study of the vector meson-nucleon scattering lengths, we are focusing on the ρ-meson case using recent CLAS threshold data for the reaction γ p → ρ p within the meson–baryon reaction model. The total σ(γ p → ρ p) and σ(γ p → ω p) cross sections are close below the momentum of the vector meson in CM q = 0.2 GeV/c. Then the ρp photoproduction cross section grows rapidly. Our result for ρp scattering length is a factor of 4 smaller than the size of the hadron and the phenomenological determination of the ωp scattering length using threshold photoproduction cross sections. The observed difference between ρp and ωp scattering lengths is of interest for further understanding within the hadron structure theory.
*U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Awards No. DE-SC0016583 and No. DE-AC05-06OR23177.
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Publication: I.I. Strakovsky, E.L. Isupov, V. Mokeev and A. Schmidt, ``rho-Meson Nucleon Scattering Length from CLAS Threshold Photoproduction Measurements,'' [arXiv:2509.04672 [nucl-th]].
I.I. Strakovsky, W.J. Briscoe, L. Pentchev, and A. Schmidt, ``Threshold Upsilon-meson photoproduction at the EIC and EicC,'' Phys. Rev. D 104, 074028 (2021).
E. Golovatch et al. [CLAS Collaboration], ``First results on nucleon resonance photocouplings from the gamma + p --> pi+ pi- p reaction,'' Phys. Lett. B 788, 371 (2019).
Presenters
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Igor I Strakovsky
- George Washington University