-- SarahHeim - 07 Jan 2008

Single Top Polarization

1. Single Top Polarization using Madevent and ONETOP samples

The polarization of single top quarks generated by Madevent was analysed. I looked at the t- as well as the s- production channel. For the t-channel the spin correlation distributions are as expected, but the s-channel distribution in the optimal basis doesn’t show the expected full polarization. Therefore I compared my results with two Tevatron data sets, one set generated by Madevent, the other one a leading order calculation with the ONETOP generator. This comparison leads to the presumption that Madevent cannot generate the polarization of s-channel produced single top quarks correctly. The application of cuts lead to the expected impact on the shape of the spin correlation distributions.

Added March 19th: We are not sure any more if it is really Madevent that makes the mistake, maybe the ONETOP code has an error in it.
Added April 11th: Either my macro or Madevent are wrong as full polarization is theoretically expected (see PolarizationMadevent).
Added May 7th: It is Madevent! I will update PolarizationMadevent.

2. Looking for Single Top Polarization in Atlas samples

Topic revision: r37 - 16 Oct 2009, TomRockwell
 

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