Eur. Phys. J. A (2007) 31: 79-93
https://doi.org/10.1140/epja/i2006-10167-8

Regular Article - Hadron Physics

Polarization observable measurements for γp → K⁺Λ and γp → K⁺Σfor energies up to 1.5 GeV

¹ IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, 38026, Grenoble, France
² Dipartimento di Fisica, Università di Roma “Tor Vergata”, via della Ricerca Scientifica 1, I-00133, Roma, Italy
³ Dipartimento di Fisica Sperimentale, Università di Torino, via P. Giuria, I-00125, Torino, Italy
⁴ INFN, Laboratori Nazionali di Frascati, via E. Fermi 40, I-00044, Frascati, Italy
⁵ INFN, Laboratori Nazionali del Sud, via Santa Sofia 44, I-95123, Catania, Italy
⁶ INFN, Sezione di Catania, via Santa Sofia 64, I-95123, Catania, Italy
⁷ INFN, Sezione di Genova, via Dodecanneso 33, I-16146, Genova, Italy
⁸ INFN, Sezione di Roma, piazzale Aldo Moro 2, I-00185, Roma, Italy
⁹ INFN, Sezione di Roma Tor Vergata, via della Ricerca Scientifica 1, I-00133, Roma, Italy
¹⁰ INFN, Sezione di Torino, I-10125, Torino, Italy
¹¹ Istituto Superiore di Sanità, viale Regina Elena 299, I-00161, Roma, Italy
¹² Dipartimento di Fisica ed Astronomia, Università di Catania, via Santa Sofia 64, I-95123, Catania, Italy
¹³ Institute for Nuclear Research, 117312, Moscow, Russia
¹⁴ IN2P3, Institut de Physique Nucléaire, 91406, Orsay, France

^* e-mail: lleres@lpsc.in2p3.fr

Received: 7 July 2006
Accepted: 21 December 2006
Published online: 24 January 2007

Abstract

Beam asymmetries and hyperon recoil polarizations for the reactions γp → K ⁺Λ and γp → K ⁺Σ⁰ have been measured from the threshold production to 1500MeV with the GRAAL facility located at the ESRF in Grenoble. These results complement the database for the beam asymmetry, covering for the first time the production threshold region. Recent theoretical analyses are presented for which the beam asymmetry data bring interesting new information and allow to better determine some resonance parameters. Most importantly, these results strengthen the need of a new D₁₃ state around 1900MeV.