EvtGen and CP-physics


Here are some of the CP related distributions that I have generated with EvtGen.

First I have looked at B->pipi. Here the "only" interesting distribution is the difference in time (in the Upsilon restframe) between the decays of the two B's. (time is expressed as c*t and is given in mm.)

The other decay that I have looked at is B->J/PSI K* with J/PSI->e+e- and K*->K pi. Here there are many more interesting distribution since the decay distributions are time dependent. In the figure the decay angle of the K* is shown for (tcp-ttag) greater than 0 and less than 0. And the tistributions are clearly different. The generation of these events were done with the following decay file (the parameters for the decay B->J/PSI KS given after the decay model "SVV_CP" are a bit arbitrary, the two first are the mass difference and beta.):

  Decay UPS4
  1.000 2 B0 B0B                VSS
  Enddecay
  Decay B0
  1.000 2 PSI  K*0              SVV_CP 0.51e12 0.4 1.0 1.0 0.0 1.0 0.0 1.0 0.0
  Enddecay
  Decay PSI
  1.000 2 E+   E-               VLL
  Enddecay
  Decay K*0
  1.000 2 K0   pi0              VSS
  Enddecay
  Decay B0B
  1.000 3 D+     e-   nueb      ISGW2
  Enddecay
  End