P Massarotti Charged kaon lifetime Paolo Massarotti Charged

P. Massarotti Charged kaon lifetime Paolo Massarotti Charged Kaon Meeting 12 october 2006

Outlook “Length” measurement: Found bug in the library extrapolation routine Studies on DC thickness “Time” measurement: Problem with fit on data Kaon decays before DC Paolo Massarotti Charged Kaon Meeting 12 october 2006

Bug problem We found a bug in the library functions that make kaon extrapolation: from the DC to the IP and from the IP to the DC After correction No differences Paolo Massarotti Charged Kaon Meeting 12 october 2006

DC thickness problem In the analysis we have used the old thickness value for the DC wall i. e. the same value used to process 2002 Data We are evaluating what happens when we use the correct value for the DC wall thickness (10% greater than the old one) which is not the value used to process Data 2002 Paolo Massarotti Charged Kaon Meeting 12 october 2006

DC thickness problem Proper time distribution old new Paolo Massarotti Charged Kaon Meeting 12 october 2006

“time” measurement We evaluated t on Data, using the time technique. There are some problems with the result (bad c 2 and great fluctuations) We think the problems are due to the T 0 refasing on Data. Therefore we want to study the events in which the kaon decays, with a p 0, before the DC wall: in these events the g‘s come from the origin. Paolo Massarotti Charged Kaon Meeting 12 october 2006

Time measurement: proper time distribution The region in red is given by the kaons decay before the DC Paolo Massarotti Charged Kaon Meeting 12 october 2006

Time measurement: resolution Inside DC Before DC Paolo Massarotti Charged Kaon Meeting 12 october 2006

Time measurement: resolution Before DC Inside DC Paolo Massarotti Charged Kaon Meeting 12 october 2006