Breakdown of QCD factorization at large Feynman x
- Departamento de Fisica, Universidad Tecnica Santa Maria, Valparaiso (Chile)
- Institute of Experimental Physics SAV, Kosice (Slovakia)
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Recent measurements by the BRAHMS Collaboration of high-p{sub T} hadron production at forward rapidities at the BNL Relativistic Heavy Ion Collider found the relative production rate (d-Au)/(p-p) to be suppressed rather than enhanced. Examining other known reactions (forward production of light hadrons, the Drell-Yan process, heavy flavor production, etc.), one notes that all of these display a similar property, namely, their cross sections in nuclei are suppressed at large x{sub F}. Since this is the region where x{sub 2} is minimal, it is tempting to interpret this as a manifestation of coherence or of a color glass condensate, whereas it is actually a simple consequence of energy conservation and takes place even at low energies. We demonstrate that in all these reactions there is a common suppression mechanism that can be viewed, alternatively, as a consequence of a reduced survival probability for large rapidity gap processes in nuclei, a Sudakov suppression, an enhanced resolution of higher Fock states by nuclei, or an effective energy loss that rises linearly with energy. Our calculations agree with the data.
- OSTI ID:
- 20699134
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 72, Issue 5; Other Information: DOI: 10.1103/PhysRevC.72.054606; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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