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physics:crosssection [2009/06/09 10:58] decianmphysics:crosssection [2009/06/09 11:01] (current) decianm
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-===== Calculation of the Cross Section =====+====== Calculation of the Cross Section ======
 ===== Introduction ===== ===== Introduction =====
 Note that the follwing numbers all depend on the settings of the Monte Carlo generator (Pythia, in this case), as none of the quantities has been measured to a high accuracy at the LHC energy. Note that the follwing numbers all depend on the settings of the Monte Carlo generator (Pythia, in this case), as none of the quantities has been measured to a high accuracy at the LHC energy.
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 Depending on what you want to calculate you also have to take into account the acceptance of the detector and the efficiency of the reconstruction. Depending on what you want to calculate you also have to take into account the acceptance of the detector and the efficiency of the reconstruction.
 The cut that is applied in Pythia to generate events that mostly decay in the LHCb detector (angular acceptance of 400mrad) is about 34.7% for B mesons and 43.2% for b bbar inclusive. The cut that is applied in Pythia to generate events that mostly decay in the LHCb detector (angular acceptance of 400mrad) is about 34.7% for B mesons and 43.2% for b bbar inclusive.
 +
 +===== Summary =====
 +The formula then is:
 +b bbar cross section * 2 * f_had * branching fraction * efficiency and acceptance.
 +
 +The yield can the be calculated by multiplying it with the integrated luminosity.
 +
  
 ===== Links ===== ===== Links =====
physics/crosssection.1244537920.txt.gz · Last modified: 2009/06/09 10:58 by decianm