This paper reports the cross section measurements for the process ep --> e J/psi p for Q(2) < 4 GeV2 at root s = 296 GeV, based on an integrated luminosity of about 0.5 pb(-1), using the ZEUS detector. The J/psi was detected in its e(+)e(-) and mu(+)mu(-) decay modes. The photoproduction cross section was measured to be 52(-12)(+7) +/- 10 nb at an average gamma p centre of mass energy of 67 GeV and 71(-20)(+13) +/- 12 nb at 114 GeV. The significant rise of the cross section compared to lower energy measurements is not in agreement with VDM models, but can be described by QCD inspired models if a rise in the gluon momentum density at low x in the proton is assumed.

Derrick, M., Krakauer, D., Magill, S., Mikunas, D., Musgrave, B., Repond, J., et al. (1995). MEASUREMENT OF THE CROSS-SECTION FOR THE REACTION GAMMA-P-]J/PSI-P WITH THE ZEUS DETECTOR AT HERA RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008. PHYSICS LETTERS. SECTION B, 350(1), 120-134 [10.1016/0370-2693(95)00403-8].

MEASUREMENT OF THE CROSS-SECTION FOR THE REACTION GAMMA-P-]J/PSI-P WITH THE ZEUS DETECTOR AT HERA RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008

MARI, Stefano Maria;
1995-01-01

Abstract

This paper reports the cross section measurements for the process ep --> e J/psi p for Q(2) < 4 GeV2 at root s = 296 GeV, based on an integrated luminosity of about 0.5 pb(-1), using the ZEUS detector. The J/psi was detected in its e(+)e(-) and mu(+)mu(-) decay modes. The photoproduction cross section was measured to be 52(-12)(+7) +/- 10 nb at an average gamma p centre of mass energy of 67 GeV and 71(-20)(+13) +/- 12 nb at 114 GeV. The significant rise of the cross section compared to lower energy measurements is not in agreement with VDM models, but can be described by QCD inspired models if a rise in the gluon momentum density at low x in the proton is assumed.
1995
Derrick, M., Krakauer, D., Magill, S., Mikunas, D., Musgrave, B., Repond, J., et al. (1995). MEASUREMENT OF THE CROSS-SECTION FOR THE REACTION GAMMA-P-]J/PSI-P WITH THE ZEUS DETECTOR AT HERA RID B-9165-2008 RID C-5889-2009 RID A-4818-2008 RID C-1693-2008. PHYSICS LETTERS. SECTION B, 350(1), 120-134 [10.1016/0370-2693(95)00403-8].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/134235
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