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Add to Calendar 4/16/2018 1:00 pm 4/16/2018 America/Chicago High Energy/Medium Energy Physics Seminar: "Color fluctuations in nucleons and pA collisions at LHC and RHIC" DESCRIPTION:

We explain that Lorentz slowing  down of the transition times between different configurations in colliding nucleons leads to emergence of the coherence phenomenon: nucleons interact with each other in configurations which are frozen during the collision time. Fluctuations of the transverse sizes of configurations lead to fluctuations of strength of the nucleon --nucleon interactions (color / strength fluctuations). This phenomenon explains presence of the inelastic diffraction at small momentum transfers and leads to fluctuations of the number of  wounded  nucleons in the proton/nucleus – nucleus collisions absent in the Glauber picture.  Based on the  QCD expectations that configurations of a nucleon  with a large-x parton, x > 0.1, have a smaller than average size, we explain gross violations of the Glauber model for dependence of jet yield on the centrality which was observed in forward jet production  in pPb collisions at the LHC and in production of high p_t  jets at  central rapidities in dAu collisions at RHIC.  The increase of the suppression with decrease of energy is also explained. This finding further suggests that at even lower energies, a nucleon with a large  x parton should interact much more weakly than in an average configuration, a phenomenon in line with explanations of the EMC effect for large x quarks in nuclei based on the color screening. We also briefly consider color fluctuations in photon – nucleus processes which will be possible to explore in the ultraperipheral heavy ion collisions at the LHC.

\n\nSPEAKER:

Mark Strikman, Penn State University

464 Loomis

false

High Energy/Medium Energy Physics Seminar: "Color fluctuations in nucleons and pA collisions at LHC and RHIC"

Speaker Mark Strikman, Penn State University
Date: 4/16/2018
Time: 1 p.m. -

2:00 pm

Location:

464 Loomis

Event Contact: Sarah Holmes
300-6194
sholmes4@illinois.edu
Sponsor:

Department of Physics

Event Type: Seminar/Symposium
 

We explain that Lorentz slowing  down of the transition times between different configurations in colliding nucleons leads to emergence of the coherence phenomenon: nucleons interact with each other in configurations which are frozen during the collision time. Fluctuations of the transverse sizes of configurations lead to fluctuations of strength of the nucleon --nucleon interactions (color / strength fluctuations). This phenomenon explains presence of the inelastic diffraction at small momentum transfers and leads to fluctuations of the number of  wounded  nucleons in the proton/nucleus – nucleus collisions absent in the Glauber picture.  Based on the  QCD expectations that configurations of a nucleon  with a large-x parton, x > 0.1, have a smaller than average size, we explain gross violations of the Glauber model for dependence of jet yield on the centrality which was observed in forward jet production  in pPb collisions at the LHC and in production of high p_t  jets at  central rapidities in dAu collisions at RHIC.  The increase of the suppression with decrease of energy is also explained. This finding further suggests that at even lower energies, a nucleon with a large  x parton should interact much more weakly than in an average configuration, a phenomenon in line with explanations of the EMC effect for large x quarks in nuclei based on the color screening. We also briefly consider color fluctuations in photon – nucleus processes which will be possible to explore in the ultraperipheral heavy ion collisions at the LHC.

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