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Theory Center Seminar<br>
Wed., Dec. 11, 2013<br>
1:00 p.m. (coffee at 12:45 p.m.) <br>
CEBAF Center, Room L102 <br>
<br>
<br>
Emanuele Mereghetti <br>
Lawrence Berkeley National Laboratory <br>
<br>
<b>Heavy Quark Production in Soft Collinear Effective Theory </b><br>
<br>
Heavy quarks play an important role in collider experiments. Due to
the large scale set by the quark mass, heavy flavor production
provides a valuable test of perturbative QCD. In addition, heavy
flavor production processes are the background to many electroweak
and new physics processes, and a great number of new physics
searches rely on the efficient tagging of b jets. It is therefore
very important to have a clear theoretical understanding of the
production of heavy flavor and heavy flavored jets . Many
theoretical tools are currently available, which allow to obtain a
successful description of heavy flavor production in fully inclusive
observable, or at moderate energies Q, close the scale of the quark
mass mQ. However, if Q >> mQ, large logarithms of the ratio
mQ/Q appear, threatening the convergence of the perturbative series,
and introducing large theoretical uncertainties. The hierarchy of
scales Q >> mQ can be exploited to establish an effective
field theory treatment of heavy quark production. Using Soft
Collinear Effective Theory (SCET), I will show how the dynamics at
the different scales that enter heavy flavor production processes
can be factorized, and large logarithms be resumed through
renormalization group equations. I will first discuss the definition
of heavy quark fragmentation function in the SCET, and its
extraction from e+ e- annihilation data. I will then move on to
hadronic collision, and discuss how SCET allows to achieve the
resummation of large logarithms for more exclusive observables than
in standard perturbative QCD.
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