Energy loss and in finite size QCD medium · Energy loss and in finite size QCD medium Alejandro...
Transcript of Energy loss and in finite size QCD medium · Energy loss and in finite size QCD medium Alejandro...
Energy loss and in finite size QCD medium
Alejandro AyalaICN-UNAM
November, 2006
Radiative vs. Collisional energy lossSingle non-photonic electron puzzle at RHIC
S. Wicks, W. Horowitz, M. Djordjevic and M. Gyulassy, nucl-th/0512076
Energy loss issues
Collisional vs radiative energy lossesRunning of αs
Non-perturbative calculations usingAdS/CFT and duality argumentsFinite size effects
S. Peigné, P.B. Gossiaux and T. Gousset, hep-ph/0509185
Energy loss computed by slowing down of parton inducedby medium produced electric field in Abelian approximation
Retardation effects: A fast parton produced in the mediumneeds to travel some distance before losing energy at thehighest rate.Conclusion: finite zise reduces the rate of energy loss.
M. Djordjevic, nucl-th/0603066Perturbative collisional energy loss, 2 → 2 processesin a finite QCD medium
Condition for interaction between jet andmedium parton to occur inside finite QCDmedium of size L.Conclusion: finite size does not affect the rateof energy loss.
Finite size effects
AA
BB
Particle production region
Q: Does the size of the interaction region, whereparticles are produced, play a role in the description of particle spectra?
Finite size effects
Qualitatively, finite size effects produce a broader transverse momentum spectrum due to Heisenberg uncertainty principle since the more localized the states are in coordinate space, the wider their spread will be in momentum space.
Bosons
Momentum distribution
Thermal occupation factorincludinng radial expansion
Wigner transform for bosons
A.A. E. Cuautle, J. Magnin, L.M. Montaño & A. Raya, Phys. Lett. B 634, 200 (2006)
Rπ=8 fm, βπ=0.6,Tπ=120 MeV
Fermions
Momentum distribution
Thermal occupation factorincludinng radial expansion
Wigner transform for fermions
A.A., E. Cuautle, J. Magnin, L.M. Montaño, nucl-th/0603039, to appear in PRC
Rπ=Rp=8 fmβπ=0.6 βp=0.53 (10% smaller than βπ)
Tπ=Tp=117 MeV
Scaling: R=R0 +C (Npart/2)1/3
R0 = 1fm, C = 1.28 fm
Two pion correlations
R vs PHENIX data
10-7
10-6
10-5
10-4
10-3
10-2
10-1
1
10
10 2
10 3
0 1 2 3 4 5 6 7 8 9 10Pt (GeV/c)
1/2π
*ptd
N/d
pt
ConclusionsConsidering finite size of particle production region, proton and pion spectra well described.Spectra from discrete set of states.Similar analysis possible for heavy quark produced in finite QCD medium?