Physics motivation heavy ion collisions

• Energy loss of heavy quarks

  • High-pT partons lose energy in the medium due to gluon radiation and elastic collisions with lower-energy partons. The latter mechanism becomes a smaller effect as the mass of the high-pT parton increases.
  • The Silicon Vertex Detector alows the investigation of energy loss for example via the measurement of open charm via D -> K+p.

• Enhancement of Charm and Beauty

  • The mechanism is the same as for the strangeness enhancement of old (early-stage parton-parton collisions, and gluon fusion), but it is not clouded by late-stage production, as it is in the case of strangeness.
  • Need to measure open charm and open beauty over a wide range of pT in AA, pA and pp

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