“Bulletin Board”

 School of Particles and Accelerator - November 2, 2011

Measurement of the b-tagging efficiency in the CMS experiment with the first LHC collisions

Dr. N. Jafari from IPM

 Abstract: Jets originating from bottom (b) quarks, play an important role in the study of Standard Model processes together with the search for new physics. In the CMS experiment a considerable effort is dedicated to the development and the performance study of so-called b-tagging algorithms. On the other hand, the top quark which is produced in pair with a high rate at the LHC, decays near 99% of the time to a b-quark. Hence it provides a rich source of b-quark jets, suitable for b-jet identification studies. In this thesis, a fully data-driven method to measure the b-tagging efficiency, using top quark events in its semi-electron final state, is developed. The result of the application of the method on the first LHC collisions in 2010 is reported. The method can be extended to a simultaneous top quark cross section and b-tagging efficiency measurement, therefore resulting in smaller uncertainties.

Time:Wednesday, November 2, 2011, 14:00

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