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Original title:
QCD factorization at forward rapidities
Authors: Nemchik, J. ; Šumbera, Michal
Document type: Papers
Conference/Event: 35th International Conference of High Energy Physics (ICHEP 2010), Paris (FR), 20100722
Year: 2010
Language: eng
Abstract: We analyze several reactions on nuclear targets at forward rapidities and different energies (at smallest experimentally accessible Bjorken x(2) in the target). Nuclear effects are then usually interpreted as a result of shadowing or the Color Glass Condensate. QCD factorization of soft and hard interactions requires the nucleus to be an universal filter for different Fock components of the projectile hadron. We demonstrate, however, that this is not the case in the vicinity of the kinematic limit, Feynman x(F) -> 1, where sharing of energy between the projectile constituents becomes an issue. The rise of suppression with x(F) is confirmed by the E772 and E886 data on the Drell-Yan and heavy quarkonium production. We show that this effect can be treated alternatively as an effective energy loss proportional to initial energy. This leads to a nuclear suppression at any energy, and predicts x(F) scaling of the suppression. We demonstrate also that the same kinematic limit can be approached in transverse momentum when the Cronin enhancement of particle production at medium-high p(T) switches to a suppression at larger p(T) violating thus QCD factorization. Such an unexpected effect seems to be confirmed by the RHIC data for pion production in d+A collisions, and even for direct photons in Au+Au collisions.
Keywords: collisions; suppression
Host item entry: 35th International Conference of High Energy Physics (ICHEP 2010)
Institution: Nuclear Physics Institute AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0281528
Permalink: http://www.nusl.cz/ntk/nusl-373394
The record appears in these collections:
Research > Institutes ASCR > Nuclear Physics Institute
Conference materials > Papers
Authors: Nemchik, J. ; Šumbera, Michal
Document type: Papers
Conference/Event: 35th International Conference of High Energy Physics (ICHEP 2010), Paris (FR), 20100722
Year: 2010
Language: eng
Abstract: We analyze several reactions on nuclear targets at forward rapidities and different energies (at smallest experimentally accessible Bjorken x(2) in the target). Nuclear effects are then usually interpreted as a result of shadowing or the Color Glass Condensate. QCD factorization of soft and hard interactions requires the nucleus to be an universal filter for different Fock components of the projectile hadron. We demonstrate, however, that this is not the case in the vicinity of the kinematic limit, Feynman x(F) -> 1, where sharing of energy between the projectile constituents becomes an issue. The rise of suppression with x(F) is confirmed by the E772 and E886 data on the Drell-Yan and heavy quarkonium production. We show that this effect can be treated alternatively as an effective energy loss proportional to initial energy. This leads to a nuclear suppression at any energy, and predicts x(F) scaling of the suppression. We demonstrate also that the same kinematic limit can be approached in transverse momentum when the Cronin enhancement of particle production at medium-high p(T) switches to a suppression at larger p(T) violating thus QCD factorization. Such an unexpected effect seems to be confirmed by the RHIC data for pion production in d+A collisions, and even for direct photons in Au+Au collisions.
Keywords: collisions; suppression
Host item entry: 35th International Conference of High Energy Physics (ICHEP 2010)
Institution: Nuclear Physics Institute AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0281528
Permalink: http://www.nusl.cz/ntk/nusl-373394
The record appears in these collections:
Research > Institutes ASCR > Nuclear Physics Institute
Conference materials > Papers
Record created 2018-03-09, last modified 2021-11-24