Possible String Theoretic Deviations from pQCD in Heavy Quark Energy Loss at the LHC

by Horowitz, William

Monday 21 May 2007, 15:30 → 16:30 Europe/Zurich

13/2-005 (CERN)

For the first few years of its running, pQCD techniques applied to high-pt jets at RHIC were highly successful in explaining the observed normalization and momentum dependence of jet suppression. However, there were signs that the picture of a weakly coupled, perturbatively understandable QGP was overly naive: the observed intermediate-p_t azimuthal anisotropy was too large; the number of nonphotonic electrons and the viscosity over entropy ratio too small. Infinitely-coupled super Yang-Mills calculations have been computed using string theoretic approaches, first as applied to the eta/s ratio, and recently to jet energy loss. Since none of the RHIC experiments currently has the ability to discern the charm versus bottom quark contribution to the nonphotonic electron spectrum, one cannot distinguish between the possible pQCD versus string theoretic solutions to the heavy quark quench puzzle. Nonetheless, pQCD gives very strong and specific predictions for the momentum dependence of charm and bottom energy loss. Deviations from this would point to new physics, and we provide several possibilities of a different dependence given by string theory calculations. The unique position of the LHC due to both its particle identification abilities and its enormous momentum reach should permit an observation of a possible discrepancy within the first year of LHC running.

Organiser(s): François Arleo, Nicolas Borghini, Yiota Foka and Urs Wiedemann
More information: http://aliceinfo.cern.ch/static/HIF/welcome.html

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