Charged kaon lifetime

F. Ambrosino, P. De Simone, P. Massarotti, V. Patera.

Paolo Massarotti K charged meeting 29 July 2004

Measure ot : length

•

Paolo Massarotti K charged meeting 29 July 2004

Background analisys

Four falimies:

good vertex (~ 69%)

kaon hits associated to daughter track (~ 20%)

Daughter hits associated to kaon track (~ 5%)

kaon broken track(~ 6%)

Daughter P*with kaon mass hypothesis

Cut on 100 MeV

Paolo Massarotti K charged meeting 29 July 2004

Measure of

on MCaG = (101.2 ) x10-2

bG = (.15 ) x10-3

T+MC = (12.35±0.08) ns

T-MC = (12.37±0.11) ns

T+true = 12.37 ns

Paolo Massarotti K charged meeting 29 July 2004

MC trueMC reco

Measure of : time

kaonfrom 0

We useneutral and charged

vertex

Paolo Massarotti K charged meeting 29 July 2004

Neutral vertex efficiency

we look for a vertex with: 1 on time

P* < 220 MeV

Paolo Massarotti K charged meeting 29 July 2004

•kaon

daughter

on time

Neutral vertex efficiency: MC true and reco

Paolo Massarotti K charged meeting 29 July 2004

MC trueMC reco

aNV = (104.7 ) x10-2

bNV = (2.0 ) x10-3

from 0 recostruction efficiency

Paolo Massarotti K charged meeting 29 July 2004

aNV = (96.15 ) x10-2

bNV = (.33 ) x10-3

Contamination:

Paolo Massarotti K charged meeting 29 July 2004

minus

plus

aNV = (2.6 ) x10-2

bNV = (.50 ) x10-3

aNV = (1.7 ) x10-2

bNV = (.91 x10-3

Neutral and charged vertex efficiency: MC true and reco

Paolo Massarotti K charged meeting 29 July 2004

aNV CV = (106.3) x10-2

bNV CV= (1.8 ) x10-3

Measure of T: MC

T+MC = (12.35 ± 0.04) ns T-

MC = (12.38 ± 0.02) ns

Paolo Massarotti K charged meeting 29 July 2004

ConclusionsTwo different methods to measure charged

kaon lifetime have been implemented

The studies on systematics must be performed on a larger sample of data

Data have to be analyzed

Paolo Massarotti K charged meeting 29 July 2004