Energy loss and in finite size QCD Energy loss and in finite size QCD medium Alejandro Ayala...

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Transcript of Energy loss and in finite size QCD Energy loss and in finite size QCD medium Alejandro Ayala...

  • Energy loss and in finite size QCD medium

    Alejandro Ayala ICN-UNAM

    November, 2006

  • Radiative vs. Collisional energy loss Single 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 losses Running of αs Non-perturbative calculations using AdS/CFT and duality arguments Finite size effects

  • S. Peigné, P.B. Gossiaux and T. Gousset, hep-ph/0509185

    Energy loss computed by slowing down of parton induced by medium produced electric field in Abelian approximation

    Retardation effects: A fast parton produced in the medium needs to travel some distance before losing energy at the highest rate. Conclusion: finite zise reduces the rate of energy loss.

  • M. Djordjevic, nucl-th/0603066 Perturbative collisional energy loss, 2 → 2 processes in a finite QCD medium

    Condition for interaction between jet and medium parton to occur inside finite QCD medium of size L. Conclusion: finite size does not affect the rate of energy loss.

  • Finite size effects

    AA

    BB

    Particle production region

    Q: Does the size of the interaction region, where particles 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 factor includinng 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 factor includinng 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 fm βπ=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 10 Pt (GeV/c)

    1/ 2π

    *p td

    N /d

    p t

  • Conclusions Considering 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?

    Energy loss and in finite size QCD medium Radiative vs. Collisional energy loss Energy loss issues S. Peigné, P.B. Gossiaux and T. Gousset, hep-ph/0509185 M. Djordjevic, nucl-th/0603066 Finite size effects Momentum distribution R?=8 fm, ??=0.6,T?=120 MeV Fermions Momentum distribution R?=Rp=8 fm??=0.6 ?p=0.53 (10% smaller than ??) T?=Tp=117 MeV Scaling: R=R0 +C (Npart/2)1/3R0 = 1fm, C = 1.28 fm Two pion correlations R vs PHENIX data Conclusions