Measurement of the Average $$B^{0}_{s}$$ Lifetime in the Decay $$B^{0}_{s} \to J/\Psi\Phi$$
- Keble Collge, Oxford (United Kingdom)
The lifetime difference between the long (CP odd) and short (CP even) lived components of the Bg meson is currently predicted to be of the order of 10 % in the Standard Model. It has been suggested that the decay Bg —>• J/\|> 4) is predominantly CP even and thus the measured average lifetime could be shorter than the lifetime measured in the inclusive decay modes. We present a measurement of the average lifetime of the 6° meson in its decay Eg —>• J/4> cj), with J/\|) —> M.+ M.~ and cj) —>• K+K-. During January 2002 and August 2003 the CDF experiment at the Tevatron has been exposed to about 135 pb" 1 of pp collisions with a centre-of-mass energy of A/S = 1.96 TeV. In the data sample collected with the J/\Jj dimuon trigger we fully reconstruct about 125 Bg —> J/\J) (J) candidates with precision silicon information. This is currently the largest exclusive Bg sample. We perform a fit to the proper decay time information to extract the average Bg lifetime and simultaneously use the mass information to disentangle signal from background. For cross-checks we measure the lifetime in the higher statistics modes Bj -» J/\J> K* and B° —> J/4> K*°, which both have similar decay topologies and kinematics. We obtain r(B°s -> J/\|> cf>) = (1.31±5:l3(stat.) ± 0.02(syst.)) ps , which is currently the best single measurement of the Bg lifetime and is consistent with other measurements. This result is not accurate enough to establish the existence of a possible significant lifetime difference between the CP odd and even states.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1336440
- Report Number(s):
- FERMILAB-THESIS-2003-61; 1312543
- Country of Publication:
- United States
- Language:
- English
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