Bibcode
Fantini, A.; di Salvo, R.; Bartalini, O.; Bellini, V.; Bocquet, J. P.; Casano, L.; Castoldi, M.; D'Angelo, A.; Franco, D.; Gervino, G.; Ghio, F.; Giardina, G.; Girolami, B.; Giusa, A.; Kuznetsov, V.; Lapik, A.; Sandri, P. Levi; Lleres, A.; Mammoliti, F.; Mandaglio, G.; Manganaro, M.; Moricciani, D.; Mushkarenkov, A. N.; Nedorezov, V.; Nicoletti, L.; Randieri, C.; Rebreyend, D.; Renard, F.; Rudnev, N.; Russo, G.; Schaerf, C.; Sperduto, M.-L.; Sutera, M.-C.; Turinge, A.; Vegna, V.; Fix, A.; Tiator, L.; Kamalov, S.
Bibliographical reference
Physical Review C, vol. 78, Issue 1, id. 015203
Advertised on:
7
2008
Citations
44
Refereed citations
35
Description
We present the first measurement of the Σ beam asymmetry in η
photoproduction on the neutron in the photon energy range from threshold
to 1.5 GeV. Data have been collected by using the tagged and linearly
polarized photon beam and the large solid angle apparatus of the GRAAL
facility. Neutron data have been selected among η photoproduction
events on the deuteron in the quasi-free kinematics approximation.
Proton data, extracted in the same way, are within errors identical to
those previously obtained on free protons at the GRAAL facility, except
for a few points falling in certain energy bins. This difference is,
however, well understood in terms of the Fermi motion of the nucleons in
the deuteron. We take the consistency of free and quasi-free proton data
as an indication that nuclear effects are negligible also for neutron
data. The ETAMAID model, in which a strong coupling of the
D15(1675) resonance to the η-neutron channel is
introduced, can explain the proton data very well, but it cannot
describe the beam asymmetry for the neutron.