Short path length pQCD corrections to energy loss in the quark gluon plasma.

High Energy Particle Physics Workshop 2016

Kolbe, Isobel^1 ; Horowitz, W.A.^1

Department of Physics, University of Cape Town, Private Bag X3, Rondebosch

7701, South Africa^1

关键词: Collective behaviour;    Correction terms;    Debye screening length;    Measurements of;    Particle correlations;    Quark-gluon plasma;    Separation distances;    Short separations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/802/1/012006/pdf
DOI  :  10.1088/1742-6596/802/1/012006

来源: IOP

【 摘 要 】

Recent surprising discoveries of collective behaviour of low-pTparticles in pA collisions at LHC hint at the creation of a hot, fluid-like QGP medium. The seemingly conflicting measurements of non-zero particle correlations and RpAthat appears to be consistent with unity demand a more careful analysis of the mechanisms at work in such ostensibly minuscule systems. We study the way in which energy is dissipated in the QGP created in pA collisions by calculating, in pQCD, the short separation distance corrections to the well-known DGLV energy loss formulae that have produced excellent predictions for AA collisions. We find that, shockingly, the large formation time (compared to the 1/μ Debye screening length) assumption that was used in the original DGLV calculation, results in a highly non-trivial cancellation of correction terms. We investigate the effect of relaxing the large formation time assumption in the final stages of the calculation and find that, not only is the effect of the small separation distance correction important even in large (∼ 5 fm) systems, but also that the correction term dominates over the leading term at high energies.