

   Request for a DESY Summer Student in 2012
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   Name : Dr. Karl-Johan Grahn     email : karl-johan.grahn@desy.de
  
   Tel  : 4671                 Room : 3/118
 
   DESY-Group/Experiment : ATLAS

 
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   Short description of the project the student should work on  :

   The DESY ATLAS group is doing a measurement of additional particle
   jets in events with top-anti-top quark pairs at the LHC. This
   measurement is important to understand QCD at hard scales and as
   background for Higgs searches and searches for new physics. With
   current LHC luminosities, there is a considerable effect of pile-up
   from several proton–proton interactions occurring in the same bunch
   crossing. This effect has to be accounted for in the
   measurement. In particular, there is a need to distinguish jets
   coming from the vertex of the main hard interaction from those of
   pile-up ones. One way to do this is to make a cut on the jet vertex
   fraction (JVF). The efficiencies of this cut need to be understood
   and corrected for. In particular, in this project we will study the
   efficiency of the JVF cut on jets stemming from bottom quarks
   (so-called b-jets).

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   Physics / Computing/ Engineering  Content of the project :

   Physics, see description



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  Special Qualifications expected from the student ( Computing,...) :
 
   Some knowledge of particle physics. Familiarity with C++ or Python
   beneficial.
 
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  Other remarks :  



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   Supervisor(s) during the project (17/07/12 - 6/09/12) :
 
  
   Name:               Tel:       email :

   Dr. Karl-Johan Grahn    4671       karl-johan.grahn@desy.de
   Dr. Judith Katzy        1471       judith.katzy@desy.de



