First measurement of the beam asymmetry in photoproduction off the proton near threshold

P. Levi Sandri; G. Mandaglio; V. De Leo; O. Bartalini; V. Bellini; J. -P. Bocquet; M. Capogni; F. Curciarello; J. -P. Didelez; A. D’Angelo; R. Di Salvo; A. Fantini; D. Franco; G. Gervino; F. Ghio; B. Girolami; A. Giusa; A. Lapik; A. Lleres; F. Mammoliti; M. Manganaro; D. Moricciani; A. Mushkarenkov; V. Nedorezov; C. Randieri; D. Rebreyend; N. Rudnev; G. Russo; C. Schaerf; M. -L. Sperduto; M. -C. Sutera; A. Turinge; V. Vegna; I. Zonta

doi:10.1140/epja/i2015-15077-0

2024 Impact factor 2.8

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2015) 51: 77
https://doi.org/10.1140/epja/i2015-15077-0

Letter

First measurement of the $\Sigma$ beam asymmetry in $\eta^{\prime}$ photoproduction off the proton near threshold

P. Levi Sandri¹, G. Mandaglio²^,3^*, V. De Leo⁴, O. Bartalini⁵^,6, V. Bellini⁷^,8, J. -P. Bocquet⁹, M. Capogni⁵^,6^,a, F. Curciarello²^,8, J. -P. Didelez¹⁰, A. D’Angelo⁵^,6, R. Di Salvo⁵, A. Fantini⁵^,6, D. Franco⁵^,6^,b, G. Gervino¹¹^,12, F. Ghio¹³^,14, B. Girolami¹³^,14, A. Giusa⁷^,8, A. Lapik¹⁵, A. Lleres⁹, F. Mammoliti⁷^,8, M. Manganaro²^,8^,c, D. Moricciani⁵, A. Mushkarenkov¹⁵, V. Nedorezov¹⁵, C. Randieri⁷^,8, D. Rebreyend⁹, N. Rudnev¹⁵, G. Russo⁷^,8, C. Schaerf⁵^,6, M. -L. Sperduto⁷^,8, M. -C. Sutera⁸, A. Turinge¹⁵, V. Vegna⁵^,6^,d and I. Zonta⁵^,6

¹ INFN, Laboratori Nazionali di Frascati, 00044, Frascati, Italy
² Dipartimento di Fisica e di Scienze della Terra, Università di Messina, 98166, Messina, Italy
³ INFN, Gruppo collegato di Messina, 98166, Messina, Italy
⁴ Dipartimento di Matematica e Fisica dell’Università “Roma Tre”, INFN, Sezione di Roma Tre, Roma, Italy
⁵ INFN, Sezione di Roma Tor Vergata, 00133, Roma, Italy
⁶ Dipartimento di Fisica, Università degli Studi di Roma Tor Vergata, 00133, Roma, Italy
⁷ Dipartimento di Fisica, Università degli Studi di Catania, 95123, Catania, Italy
⁸ INFN, Sezione di Catania, 95123, Catania, Italy
⁹ LPSC, Université Grenoble-Alpes, CNRS/IN2P3, Grenoble IPN, F-38026, Grenoble, France
¹⁰ IN2P3, Institut de Physique Nucléaire, 91406, Orsay, France
¹¹ INFN, Sezione di Torino, 10125, Torino, Italy
¹² Dipartimento di Fisica Sperimentale, Università degli Studi di Torino, I-10125, Torino, Italy
¹³ INFN, Sezione di Roma, 00185, Roma, Italy
¹⁴ Istituto Superiore di Sanità, I-00161, Roma, Italy
¹⁵ Institute for Nuclear Research, 60-letiya Oktyabrya prospekt 7a, 117312, Moscow, Russia

^* e-mail: gmandaglio@unime.it

Received: 16 April 2015
Revised: 16 June 2015
Accepted: 18 June 2015
Published online: 8 July 2015

Abstract

The $\Sigma$ beam asymmetry in $\eta^{\prime}$ photoproduction off the proton was measured at the GrAAL polarised photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson production angle shows a clear structure, more pronounced at the lowest one, with a change of sign around $90^{\circ}$ . The observed behaviour is compatible with P-wave D-wave (or S-wave F-wave) interference, the closer to threshold the stronger. The results are compared to the existing state-of-the-art calculations that fail to account for the data.

Present address: ENEA - C.R. Casaccia, Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, Via Anguillarese, 301, I-00123, Roma, Italy

Present address: IPNL - 43, Bd du 11 Novembre 1918, Fr69622, Villeurbanne Cedex, France

Present address: Universidad de La Laguna, Instituto de Astrofísica de Canarias, E-38205, La Laguna, Tenerife, Spain

Present address: Universität Bonn, Physikalisches Institut, Nu¿allee 12, D-53115, Bonn, Germany

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