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Title: Lifetime difference in the B$$0\atop{s}$$ system from untagged B$$0\atop{s}$$ → J/ΨΦ decay at √s= 1.96 TeV at D0 detector

Abstract

In this dissertation, they present a study of the untagged decay of B$$0\atop{s}$$ → J/ΨΦ, the final state of which is a superposition of the CP-even and CP-odd states. Within the framework of the standard model (SM), to a good approximation, the two CP eigenstates of the (B$$0\atop{s}$$, $$\bar{B}$$$0\atop{s}$$) system are equivalent to mass eigenstates. The data collected by the D0 detector between June 2002 to August 2004 (an integrated luminosity of approximately 450 pb -1) has been used for the analysis presented in this thesis. From a simultaneous fit to the B$$0\atop{s}$$ candidate mass, lifetime, and the angular distribution of the decay products, they obtain the CP-odd fraction in the final state at production time to be 0.16 ±} 0.10(stat) ± 0.02(syst). The average lifetime of the (B$$0\atop{s}$$, $$\bar{B}$$$0\atop{s}$$) system is measured to be 1.39$$+0.13\atop{-0.16}$$(stat)$$+0.01\atop{-0.02}$$(syst) ps, with the relative width difference between the heavy and light mass eigenstates, Δγ/$$\bar{γ}$$ = (γ LH)/$$\bar{γ}$$ = 0.24$$+0.16\atop{-0.38}$$(stat)$$+0.03\atop{-0.04}$$(syst). With the additional constraint from the world average of the B$$0\atop{s}$$ lifetime measurements using semileptonic decays, they find average lifetime of the (B$$0\atop{s}$$, $$\bar{B}$$$0\atop{s}$$) system 1.39 ± 0.06 ps with Δγ/$$\bar{γ}$$ = 0.25$$+0.14\atop{-0.15}$$. They have also done B 0 lifetime measurement for its analogous decay mode to J/Ψ}K*. With this measurement they get B 0 lifetime 1.530 ± 0.043(stat) ± 0.023(syst) ps. Using above results, they get 0.91 ± 0.09(stat) ± 0.003(syst), for the ratio of the B$$0\atop{s}$$ and B 0 lifetimes ($$\bar{γ}$$(B$$0\atop{s}$$)/γ(B 0)). These measurements are consistent with the predictions of SM within the measurement uncertainty.

Authors:
 [1]
  1. Tata Inst. of Fundamental Research (TIFR), Mumbai (India)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
907797
Report Number(s):
FERMILAB-THESIS-2006-40
TRN: US0703314
DOE Contract Number:
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANGULAR DISTRIBUTION; DAUGHTER PRODUCTS; DECAY; EIGENSTATES; LIFETIME; LUMINOSITY; PRODUCTION; SEMILEPTONIC DECAY; STANDARD MODEL; Experiment-HEP

Citation Formats

Chandra, Avdhesh. Lifetime difference in the B$0\atop{s}$ system from untagged B$0\atop{s}$ → J/ΨΦ decay at √s= 1.96 TeV at D0 detector. United States: N. p., 2006. Web. doi:10.2172/907797.
Chandra, Avdhesh. Lifetime difference in the B$0\atop{s}$ system from untagged B$0\atop{s}$ → J/ΨΦ decay at √s= 1.96 TeV at D0 detector. United States. doi:10.2172/907797.
Chandra, Avdhesh. Sun . "Lifetime difference in the B$0\atop{s}$ system from untagged B$0\atop{s}$ → J/ΨΦ decay at √s= 1.96 TeV at D0 detector". United States. doi:10.2172/907797. https://www.osti.gov/servlets/purl/907797.
@article{osti_907797,
title = {Lifetime difference in the B$0\atop{s}$ system from untagged B$0\atop{s}$ → J/ΨΦ decay at √s= 1.96 TeV at D0 detector},
author = {Chandra, Avdhesh},
abstractNote = {In this dissertation, they present a study of the untagged decay of B$0\atop{s}$ → J/ΨΦ, the final state of which is a superposition of the CP-even and CP-odd states. Within the framework of the standard model (SM), to a good approximation, the two CP eigenstates of the (B$0\atop{s}$, $\bar{B}$$0\atop{s}$) system are equivalent to mass eigenstates. The data collected by the D0 detector between June 2002 to August 2004 (an integrated luminosity of approximately 450 pb-1) has been used for the analysis presented in this thesis. From a simultaneous fit to the B$0\atop{s}$ candidate mass, lifetime, and the angular distribution of the decay products, they obtain the CP-odd fraction in the final state at production time to be 0.16 ±} 0.10(stat) ± 0.02(syst). The average lifetime of the (B$0\atop{s}$, $\bar{B}$$0\atop{s}$) system is measured to be 1.39$+0.13\atop{-0.16}$(stat)$+0.01\atop{-0.02}$(syst) ps, with the relative width difference between the heavy and light mass eigenstates, Δγ/$\bar{γ}$ = (γL/γH)/$\bar{γ}$ = 0.24$+0.16\atop{-0.38}$(stat)$+0.03\atop{-0.04}$(syst). With the additional constraint from the world average of the B$0\atop{s}$ lifetime measurements using semileptonic decays, they find average lifetime of the (B$0\atop{s}$, $\bar{B}$$0\atop{s}$) system 1.39 ± 0.06 ps with Δγ/$\bar{γ}$ = 0.25$+0.14\atop{-0.15}$. They have also done B0 lifetime measurement for its analogous decay mode to J/Ψ}K*. With this measurement they get B0 lifetime 1.530 ± 0.043(stat) ± 0.023(syst) ps. Using above results, they get 0.91 ± 0.09(stat) ± 0.003(syst), for the ratio of the B$0\atop{s}$ and B0 lifetimes ($\bar{γ}$(B$0\atop{s}$)/γ(B0)). These measurements are consistent with the predictions of SM within the measurement uncertainty.},
doi = {10.2172/907797},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

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  • This thesis describes a measurement of the Bmore » $$0\atop{d}$$ lifetime in the decay to (J/ΨK$$0\atop{S}$$), using 114 pb -1 of data collected by the D0 experiment at the Tevatron from October 15, 2002, to June 10, 2003. The measurement is motivated by the tests of the Standard Model that it makes possible. These include tests of Heavy Quark Effective Theory predicting B-meson lifetimes, and of the complex phase in the CKM-matrix as the source of CP-violation in B$$0\atop{d}$$ decays to (J/ΨK$$0\atop{S}$$).« less
  • We report the first observation of Bmore » $$0\atop{s}$$ → Ψ(2S)Φ decay in p$$\bar{p}$$ collisions at √s = 1.96 TeV using 360 pb -1 of data collected by the CDF II detector at the Fermilab Tevatron. We present the first measurement of the relative branching fraction B$$0\atop{s}$$ → Ψ(2S)Φ / B(B$$0\atop{s}$$ → J/ΨΦ) = 0.52±0.13 (stat.)±0.04(syst.)±0.06(BR) using the Ψ(2S) → μ +μ - decay mode.« less
  • After years of preparation, data taking with the upgraded D0 detector at the Tevatron proton-antiproton collider has begun. The large amount of data produced in a pmore » $$\bar{p}$$-collider requires sophisticated triggers to filter out the interesting events. Described in this thesis is the development of trigger software for the newly implemented Silicon Microstrip Tracker. D0 is a multi-purpose detector with a broad physics program. one area being studied at D0 is B mesons. An algorithm for reconstructing the B$$0\atop{s}$$ and B$$0\atop{d}$$ mesons and for measuring their lifetimes has been developed and is described in this thesis. The results suggest that an improvement of the current lifetime measurements can be achieved within the next two years. The reconstruction of a J/Ψ meson forms the basis for a wide range of b-physics. Data taken with the muon system during the commissioning period of the detector has been analyzed and a signal for the J/Ψ meson has been found. Systematic transfer of HEP technologies into other areas and their commercial exploitation plays an important role in the future of particle physics. An area of particular interest is DNA sequencing as shown by the recent completion of the sequencing of the human genome. The final part of this thesis details the development of a simulation for a high throughput sequencing device which is currently being developed at Imperial College.« less
  • We present the first observation of the decaymore » $$\bar{B}$$$0\atop{s}$$→ D$$±\atop{s}$$ K∓ and measure the relative branching fraction of $$\bar{B}$$$0\atop{s}$$ → D$$±\atop{s}$$ K∓ to $$\bar{B}$$$0\atop{s}$$ → D$$+\atop{s}$$ π -. The measurement of the relative branching fraction is performed by applying a fit in invariant mass and specific ionization to 1.2 fb -1 of D s(φπ)X data collected with the CDF II detector in pp collisions at √ s = 1.96 TeV at the Fermilab Tevatron collider. We measure B $$\bar{B}$$$0\atop{s}$$ → D$$±\atop{s}$$ K∓ /B $$\bar{B}$$$0\atop{s}$$ → D$$+\atop{s}$$ π - = 0.107±0.019(stat)±0.008(sys). The statistical significance of the $$\bar{B}$$$0\atop{s}$$ → D$$±\atop{s}$$ K signal is 7.9σ. To cross-check our analysis method, we also measure B $$\bar{B0}$$→ D +K - /B $$\bar{B0}$$ → D +π - and B $$\bar{B0}$$ → D +*K - /B $$\bar{B0}$$ → D *+π - and verify that our results are in agreement with the world average.« less
  • Bmore » $$0\atop{s}$$ mixing studies provide a precision test of Charge-Parity violation in the Standard Model. A measurement of Δm s constrains elements of the CKM quark rotation matrix [1], providing a probe of Standard Model Charge-Parity violation. This thesis describes a study of $$0\atop{s}$$ mixing in the semileptonic decay $$0\atop{s}$$ → D s - μ +vX, where D s - → Φπ -, using data collected at the D-Zero detector at Fermi National Accelerator in atavia, Illinois. Approximately 2.8 fb -1 of data collected between April 2002 and August 2007 was used, covering the entirety of the Tevatron's RunIIa (April 2002 to March 2006) and part of RunIIb (March 2006-August 2007). Taggers using both opposite-side and same-side information were used to obtain the flavor information of the s 0 meson at production. The charge of the muon in the decay $$0\atop{s}$$ → D s -μ +vX was used to determine the flavor of the $$0\atop{s}$$ at decay. The $$d\atop{0}$$ mixing frequency, Δm d, was measured to verify the analysis procedure. A log-likelihood calculation was performed, and a measurement of Δm s was obtained. The final result was Δm s = 18.86 ± 0.80(stat.) ± 0.37(sys.) with a significance of 2.6σ.« less