The photoproduction of D*(+/-)(2010) mesons associated with a leading neutron has been observed with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 80 pb(-1). The neutron carries a large fraction, x(L) > 0.2, of the incoming proton beam energy and is detected at very small production angles, theta(n) < 0.8 mrad, an indication of peripheral scattering. The D* meson is centrally produced with pseudorapidity \eta\ < 1.5, and has a transverse momentum p(T) > 1.9 GeV, which is large compared to the average transverse momentum of the neutron of 0.22 GeV The ratio of neutron-tagged to inclusive D* production is 8.85 +/- 0.93(stat.)(-0.61)(+0.48)(syst.)% in the photon-proton center-of-mass energy range 130 < W < 280 Gev The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.
Photoproduction of D*(+/-) mesons associated with a leading neutron
BRUGNERA, RICCARDO;CARLIN, ROBERTO;GARFAGNINI, ALBERTO;A. Longhin;
2004
Abstract
The photoproduction of D*(+/-)(2010) mesons associated with a leading neutron has been observed with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 80 pb(-1). The neutron carries a large fraction, x(L) > 0.2, of the incoming proton beam energy and is detected at very small production angles, theta(n) < 0.8 mrad, an indication of peripheral scattering. The D* meson is centrally produced with pseudorapidity \eta\ < 1.5, and has a transverse momentum p(T) > 1.9 GeV, which is large compared to the average transverse momentum of the neutron of 0.22 GeV The ratio of neutron-tagged to inclusive D* production is 8.85 +/- 0.93(stat.)(-0.61)(+0.48)(syst.)% in the photon-proton center-of-mass energy range 130 < W < 280 Gev The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.Pubblicazioni consigliate
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