Measurement of the cross-section ratio sigma psi (2S)/sigma J/psi (1S) in exclusive photoproduction at HERA

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Abt, I, Adamus, M, Aggarwal, R, Aushev, V, Behnke, O, Bertolin, A, Bloch, I, Brock, I, Brook, NH, Brugnera, R et al (show 72 more authors) , Bruni, A, Bussey, PJ, Caldwell, A, Catterall, CD, Chwastowski, J, Ciborowski, J, Ciesielski, R, Cooper-Sarkar, AM, Corradi, M, Dementiev, RK, Dusini, S, Ferrando, J, Foster, B, Gallo, E, Gangadharan, D, Garfagnini, A, Geiser, A, Grzelak, G, Gwenlan, C, Hochman, D, Jomhari, NZ, Kadenko, I, Karshon, U, Kaur, P, Klanner, R, Klein, U ORCID: 0000-0001-7391-5330, Korzhavina, IA, Kovalchuk, N, Kuze, M, Levchenko, BB, Levy, A, Lohr, B, Lohrmann, E, Longhin, A, Lorkowski, F, Makarenko, I, Malka, J, Masciocchi, S, Nagano, K, Nam, JD, Onishchuk, Yu, Paul, E, Pidhurskyi, I, Polini, A, Przybycin, M, Quintero, A, Rubinsky, I, Ruspa, M, Schneekloth, U, Schorner-Sadenius, T, Selyuzhenkov, I, Shchedrolosiev, M, Shcheglova, LM, Skillicorn, IO, Slominski, W, Solano, A, Stanco, L, Stefaniuk, N, Surrow, B, Tokushuku, K, Tomaszewska, J, Trofymov, A, Turkot, O, Tymieniecka, T, Verbytskyi, A, Abdullah, WAT Wan, Wichmann, K, Wing, M, Yamada, S, Yamazaki, Y, Zarnecki, AF and Zenaiev, O (2022) Measurement of the cross-section ratio sigma psi (2S)/sigma J/psi (1S) in exclusive photoproduction at HERA. JOURNAL OF HIGH ENERGY PHYSICS, 2022 (12).

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The exclusive photoproduction reactions <jats:italic>γp</jats:italic> → <jats:italic>J/ψ</jats:italic>(1<jats:italic>S</jats:italic>)<jats:italic>p</jats:italic> and <jats:italic>γp</jats:italic> → <jats:italic>ψ</jats:italic>(2<jats:italic>S</jats:italic>)<jats:italic>p</jats:italic> have been measured at an <jats:italic>ep</jats:italic> centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 373 pb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. The measurement was made in the kinematic range 30 <jats:italic>&lt; W &lt;</jats:italic> 180 GeV, <jats:italic>Q</jats:italic><jats:sup>2</jats:sup><jats:italic>&lt;</jats:italic> 1 GeV<jats:sup>2</jats:sup> and |<jats:italic>t</jats:italic>| <jats:italic>&lt;</jats:italic> 1 GeV<jats:sup>2</jats:sup>, where <jats:italic>W</jats:italic> is the photon-proton centre-of-mass energy, <jats:italic>Q</jats:italic><jats:sup>2</jats:sup> is the photon virtuality and <jats:italic>t</jats:italic> is the squared four-momentum transfer at the proton vertex. The decay channels used were <jats:italic>J/ψ</jats:italic>(1<jats:italic>S</jats:italic>) <jats:italic>→ μ</jats:italic><jats:sup>+</jats:sup><jats:italic>μ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup>, <jats:italic>ψ</jats:italic>(2<jats:italic>S</jats:italic>) <jats:italic>→ μ</jats:italic><jats:sup>+</jats:sup><jats:italic>μ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> and <jats:italic>ψ</jats:italic>(2<jats:italic>S</jats:italic>) <jats:italic>→ J/ψ</jats:italic>(1<jats:italic>S</jats:italic>)<jats:italic>π</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> with subsequent decay <jats:italic>J/ψ</jats:italic>(1<jats:italic>S</jats:italic>) <jats:italic>→ μ</jats:italic><jats:sup>+</jats:sup><jats:italic>μ</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup>. The ratio of the production cross sections, <jats:italic>R</jats:italic> = <jats:italic>σ</jats:italic><jats:sub><jats:italic>ψ</jats:italic>(2<jats:italic>S</jats:italic>)</jats:sub><jats:italic>/σ</jats:italic><jats:sub><jats:italic>J/ψ</jats:italic>(1<jats:italic>S</jats:italic>)</jats:sub>, has been measured as a function of <jats:italic>W</jats:italic> and |<jats:italic>t</jats:italic>| and compared to previous data in photoproduction and deep inelastic scattering and with predictions of QCD-inspired models of exclusive vector-meson production, which are in reasonable agreement with the data.</jats:p>

Item Type:	Article
Uncontrolled Keywords:	Diffraction, Heavy Quark Production, Lepton-Nucleon Scattering, Quarkonium
Divisions:	Faculty of Science and Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	14 Mar 2023 14:56
Last Modified:	23 Mar 2023 00:43
DOI:	10.1007/JHEP12(2022)164
Open Access URL:	https://doi.org/10.1007/JHEP12(2022)164
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3169057