Measurement of CP Asymmetries in B0 to Phi K0 and B0 to K+K-Ks Decays

Measurement of CP Asymmetries in B0 to Phi K0 and B0 to K+K-Ks Decays
Title Measurement of CP Asymmetries in B0 to Phi K0 and B0 to K+K-Ks Decays PDF eBook
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Pages
Release 2005
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ISBN

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We measure the time-dependent CP asymmetry parameters in B° 2!KK−K° based on a data sample of approximately 227 million B-meson pairs recorded at the [Upsilon](4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. We reconstruct two-body B° decays to [phi](1020)K{sub s}° and [phi](1020)K{sub L}°, and the three-body decay KK−K{sub s}° with [phi](1020)K{sub s}° excluded. For the B° 2![phi]K° decays, they measure sin 2[beta]{sub eff}([phi]K°) = +0.50 ± 0.25(stat){sub -0.04}{sup +0.07}(syst). The B° 2!K+K−K{sub s}° decays are dominated by K+K− S-wave, as determined from an angular analysis; they measure sin 2[beta]{sub eff} (K+K−K{sub s}°) = +0.55 ± 0.22(stat) ± 0.04(syst) ± 0.11(CP), where the last error is due to the uncertainty in the fraction of CP-even contributions to the decay amplitude. We find no evidence for direct CP violation.

Measurement of CP Asymmetry in B° --] KK−K°S Decays

Measurement of CP Asymmetry in B° --] KK−K°S Decays
Title Measurement of CP Asymmetry in B° --] KK−K°S Decays PDF eBook
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Pages 5
Release 2004
Genre
ISBN

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The authors present preliminary measurements of the CP asymmetry parameters and CP content in B° --> KK−K{sub s}° decays, with [phi]K{sub s}° events excluded. In a sample of 227 M B{bar B} pairs collected by the BABAR detector at the PEP-II B Factory at SLAC, they find the CP parameters to be S = -0.42 ± 0.17 ± 0.04 and C = 0.10 ± 0.14 ± 0.06, where the first error is statistical and the second systematic. Extracting the fraction of CP-even final states from angular moments f{sub even} = 0.89 ± 0.08 ± 0.06, and setting C = 0, they determine sin 2[beta] = 0.55 ± 0.22 ± 0.04 ± 0.11, where the last error is due to uncertainty on the CP content.

Measurement of CP Asymmetry in B0 to Ks Pi0 Pi0 Decays

Measurement of CP Asymmetry in B0 to Ks Pi0 Pi0 Decays
Title Measurement of CP Asymmetry in B0 to Ks Pi0 Pi0 Decays PDF eBook
Author
Publisher
Pages 8
Release 2007
Genre
ISBN

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We present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay into the CP = +1 final state K{sub S}°?°?°, with K{sub S}° →??−. We use a sample of approximately 227 million B-meson pairs recorded at the?(4S) resonance with the BABAR detector at the PEP-II B-Factory at SLAC. From an unbinned maximum likelihood fit we extract the mixing-induced CP-violation parameter S = 0.72 ± 0.71 ± 0.08 and the direct CP-violation parameter C = 0.23 ± 0.52 ± 0.13, where the first uncertainty is statistical and the second systematic.

Measurement of CP Asymmetries in B0-]Ks Pi0 Pi0 Decays

Measurement of CP Asymmetries in B0-]Ks Pi0 Pi0 Decays
Title Measurement of CP Asymmetries in B0-]Ks Pi0 Pi0 Decays PDF eBook
Author J. C. Chen
Publisher
Pages 17
Release 2005
Genre
ISBN

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The authors present a preliminary measurement of the time-dependent CP asymmetry for the neutral B-meson decay into the CP = +1 final state K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}, with K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -} and {pi}{sup 0} {yields} {gamma}{gamma}. They use a sample of approximately 227 million B-meson pairs recorded at the {Upsilon}(4S) resonance by the BABAR detector at the PEP-II B-Factory at SLAC. From a maximum likelihood fit they extract the mixing-induced CP-violation parameter S{sub K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}} = 0.84 {+-} 0.71(stat) {+-} 0.08(syst) and the direct CP-violation parameter C{sub K{sub S}{sup 0}}{pi}{sup 0}{pi}{sup 0} = 0.27 {+-} 0.52(stat) {+-} 0.13(syst), where the first uncertainty is statistical and the second systematic.

Time-Dependent CP Violation Measurements

Time-Dependent CP Violation Measurements
Title Time-Dependent CP Violation Measurements PDF eBook
Author Markus Röhrken
Publisher Springer Science & Business Media
Pages 205
Release 2013-10-17
Genre Science
ISBN 3319007262

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This thesis describes a high-quality, high-precision method for the data analysis of an interesting elementary particle reaction. The data was collected at the Japanese B-meson factory KEKB with the Belle detector, one of the most successful large-scale experiments worldwide. CP violation is a subtle quantum effect that makes the world look different when simultaneously left and right and matter and antimatter are exchanged. This being a prerequisite for our own world to have developed from the big bang, there are only a few experimental indications of such effects, and their detection requires very intricate techniques. The discovery of CP violation in B meson decays garnered Kobayashi and Maskawa, who had predicted these findings as early as 1973, the 2008 Nobel prize in physics. This thesis describes in great detail what are by far the best measurements of branching ratios and CP violation parameters in two special reactions with two charm mesons in the final state. It presents an in-depth but accessible overview of the theory, phenomenology, experimental setup, data collection, Monte Carlo simulations, (blind) statistical data analysis, and systematic uncertainty studies.

Measurement of CP Violation Observables and Parameters for the Decays $B{̂\pm}\to DK{̂*\pm}$

Measurement of CP Violation Observables and Parameters for the Decays $B{̂\pm}\to DK{̂*\pm}$
Title Measurement of CP Violation Observables and Parameters for the Decays $B{̂\pm}\to DK{̂*\pm}$ PDF eBook
Author
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Pages 16
Release 2010
Genre
ISBN

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We study the decay B− → DK*− using a sample of 379 x 106?(4S) → B{bar B} events collected with the BABAR detector at the PEP-II B-factory. We perform a 'GLW' analysis where the D meson decays into either a CP-even (CP+) eigenstate (KK−,?+?−), CP-odd (CP- ) eigenstate (K{sub S}°?°, K{sub S}°?, K{sub S}°?) or a non-CP state (K−?+). We also analyze D meson decays into K+?− from a Cabibbo-favored {bar D}° decay or doubly suppressed D° decay ('ADS' analysis). We measure observables that are sensitive to the CKM angle?: the partial-rate charge asymmetries A{sub CP±}, the ratios R{sub CP±} of the B-decay branching fractions in CP± and non-CP decay, the ratio R{sub ADS} of the charge-averaged branching fractions, and the charge asymmetry A{sub ADS} of the ADS decays: A{sub CP+} = 0.09 ± 0.13 ± 0.06, A{sub CP-} = -0.23 ± 0.21 ± 0.07, R{sub CP+} = 2.17 ± 0.35 ± 0.09, R{sub CP-} = 1.03 ± 0.27 ± 0.13, R{sub ADS} = 0.066 ± 0.031 ± 0.010, and A{sub ADS} = -0.34 {+-} 0.43 {+-} 0.16, where the first uncertainty is statistical and the second is systematic. Combining all the measurements and using a frequentist approach yields the magnitude of the ratio between the Cabibbo-suppressed and favored amplitudes, r{sub B} = 0.31 with a one (two) sigma confidence level interval of [0.24, 0.38] ([0.17, 0.43]). The value r{sub B} = 0 is excluded at the 3.3 sigma level. A similar analysis excludes values of? in the intervals [0, 7]{sup o}, [55, 111]{sup o}, and [175, 180]{sup o} ([85, 99]{sup o}) at the one (two) sigma confidence level.

Branching Fractions and CP Asymmetries in B0-]K+K-Ks and B+-]K+KsKs

Branching Fractions and CP Asymmetries in B0-]K+K-Ks and B+-]K+KsKs
Title Branching Fractions and CP Asymmetries in B0-]K+K-Ks and B+-]K+KsKs PDF eBook
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Pages 7
Release 2004
Genre
ISBN

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The authors measure the branching fractions and CP asymmetries in the decays B° 2!KK−K{sub S}° and B 2!K+K{sub S}°K{sub S}° using a sample of approximately 122 million B{bar B} pairs collected by the BABAR detector. From a time-dependent analysis of the K+K− K{sub S}° sample that excludes [phi]K{sub S}°, the values of the CP-violation parameters are S = -0.56 ± 0.25 ± 0.04 and C = -0.10 ± 0.19 ± 0.10, where the first uncertainty is statistical, the second is systematic. They confirm that the final state is nearly purely CP-even. Using this result and setting C = 0, they extract the Standard Model parameter sin 2[beta] = 0.57 ± 0.26 ± 0.04−0{sup +0.17} where the last error is due to uncertainty on the CP content. The present the first measurement of the CP-violating charge asymmetry A{sub CP} B+ 2!K+K{sub S}°K{sub S}° = -0.04 ± 0.11 ± 0.02, with a 90% confidence-level interval of [-0.23, 0.15]. The branching fractions are [Beta](B° 2!K+K−K°) = (23.8 ± 2.0 ± 1.6) x 10−6 and [Beta](B+ 2!K+K{sub S}°K{sub S}°) = (10.7 ± 1.2 ± 1.0) x 10−6.