New measurements from fully reconstructed hadronic final states of the $$B^0_2$$ meson at CDF II experiment

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 2006

DOI:https://doi.org/10.2172/1345596· OSTI ID:1345596

Da Ronco, Saverio ^[1]

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1. Univ. of Padua (Italy)

This thesis reports the reconstruction and lifetime measurement of B⁺, B$$0/atop{d}$$ and B$$0/atop{s}$$ mesons, performed using fully reconstructed hadronic decays collected by a dedicated trigger at CDF II experiment. This dedicated trigger selects significantly displaced tracks from primary vertex of p$$\bar{p}$$ collisions generated at Tevatron collider, obtaining, in this way, huge data samples enriched of long-lived particles, and is therefore suitable for reconstruction of B meson in hadronic decay modes. Due to the trigger track impact parameter selections, the proper decay time distributions of the B mesons no longer follow a simply exponential decay law. This complicates the lifetime measurement and requires a correct understanding and treatment of all the involved effects to keep systematic uncertainties under control. This thesis presents a method to extract the lifetime of B mesons in “ct- biased” samples, based on a Monte Carlo approach, to correct for the effects of the trigger and analysis selections. We present the results of this method when applied on fully re- constructed decays of B collected by CDF II in the data taking runs up to August 2004, corresponding to an integrated luminosity of about 360 pb^-1. The lifetimes are extracted using the decay modes B⁺ → $$\bar{D}$$⁰π⁺,B$$0\atop{d}$$ → D^-π⁺, B$$0\atop{d}$$ → D^-π⁺π^-π⁺, B$$0\atop{s}$$ → D$$-\atop{s}$$π⁺ and B$$0\atop{s}$$ → D$$-\atop{s}$$ π⁺π^-π⁺(and c.c.) and performing combined mass-lifetime unbinned maximum likelihood fits.

• 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: 1345596
• Report Number(s): FERMILAB-THESIS-2006-96; 1515446
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS