Measurement of the CP Violating Phase $$\boldsymbol{\sin(2\beta_{s})}$$ using $$\boldsymbol{B^{0}_{s}\rightarrow J/\psi\phi}$$ Decays at CDF
- Carnegie Mellon Univ., Pittsburgh, PA (United States)
A B0 s meson can oscillate into its anti-particle, the $$\bar{B}$$0 s meson, before decaying. CP violation in this system is made possible by the presence of amplitudes from both mixed and unmixed B0 s meson decays. The CP violating phase βs appears in the interference between the decay amplitudes. The quantity sin(2βs) is expected to be small in the standard model. Thus, measuring a large value for sin(2βs) would be an unequivocal sign of new physics participation in the B0 s mixing loop diagram. In this thesis, we present a latest measurement of sin(2βs), using 5.2 fb-1 of data collected at CDF from p$$\bar{p}$$ collisions at a center of mass energy of √s=1.96 TeV. A time-dependent angular analysis, with the production flavor of the B0 s meson identified with flavor tagging methods, is used to extract sin(2βs) from ~6500 B0 s→ J/ψφ decays. Other parameters of interest, such as the B0 s lifetime and the decay width difference between the heavy and light B0 s mass eigenstates are determined to high precision. Also, the effect of potential contributions to the final state from B0 s → J/ψf0 and B0 s→ J/ψK+K- decays is considered for the first time. We present 68% and 95% confidence regions in the βs plane. The probability that the observed central value is a fluctuation of the data from the standard model expected value of βs is calculated to be 44%. The observed confidence region shows better agreement with the standard model prediction than previous measurements.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1024914
- Report Number(s):
- FERMILAB-THESIS-2010-70; TRN: US1104847
- Country of Publication:
- United States
- Language:
- English
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