Measurements of Time-dependent CP Asymmetries in B0 --] D(*)+D(*)- Decays

Measurements of Time-dependent CP Asymmetries in B0 --] D(*)+D(*)- Decays
Title Measurements of Time-dependent CP Asymmetries in B0 --] D(*)+D(*)- Decays PDF eBook
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Pages 13
Release 2009
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ISBN

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We present new measurements of time-dependent CP asymmetries for B° --> D{sup (*)+}d{sup (*)-} decays using (467 ± 5) x 106 B{bar B} pairs collected with the BABAR detector located at the PEP-II B Factory at the Stanford Linear Accelerator Center. We determine the CP-odd fraction of the B° --> D*D*− decays to be R(up tack) = 0.158 ± 0.028 ± 0.006 and find CP asymmetry parameters for the CP-even component of the decay S+ = -0.76 ± 0.16 ± 0.04 and C+ = 0.00 ± 0.12 ± 0.02. We measure S = -0.63±0.36±0.05 and C = -0.07±0.23±0.03 for B° --> DD−, S = -0.62±0.21±0.03 and C = 0.08 ± 0.17 ± 0.04 for B° --> D*+D−, and S = -0.73 ± 0.23 ± 0.05 and C = 0.00 ± 0.17 ± 0.03 for B° --> D+D*−. For the B° --> D*{sup ±}D{sup {-+}} decays, we also determine the CP-violating asymmetry A = 0.008 ± 0.048 {+-} 0.013. In each case, the first uncertainty is statistical and the second is systematic. The measured values for the asymmetries are all consistent with the Standard Model.

Measurement of Time-Dependent CP Asymmetries in B0 to D(*)D Decays

Measurement of Time-Dependent CP Asymmetries in B0 to D(*)D Decays
Title Measurement of Time-Dependent CP Asymmetries in B0 to D(*)D Decays PDF eBook
Author
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Pages 7
Release 2005
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The authors present a first measurement of CP asymmetries in neutral B decays to DD−, and updated CP asymmetry measurements in decays to D*D− and D*−D+. They use fully-reconstructed decays collected in a data sample of (232 ± 3) x 106 [Upsilon](4S) 2!B{bar B} events in the BABAR detector at the PEp-II asymmetric-energy B Factory at SLAC. they determine the time-dependent asymmetry parameters to be S{sub D*+D−} = -0.54 ± 0.35 ± 0.07, C{sub D*+D−} = 0.09 ± 0.25 ± 0.06, S{sub D*−D{sup +}} = -0.29 ± 0.33 ± 0.07, C{sub D*−D{sup +}} = 0.17 ± 0.24 ± 0.04, S{sub D{sup +}D{sup -}} = -0.29 ± 0.63 ± 0.06, and C{sub D{sup +}D{sup -}} = 0.11 ± 0.35 ± 0.06, where in each case the first error is statistical and the second error is systematic.

Measurement of Time-Dependent CP Asymmetry in B0-]ccbar K(*)0 Decays

Measurement of Time-Dependent CP Asymmetry in B0-]ccbar K(*)0 Decays
Title Measurement of Time-Dependent CP Asymmetry in B0-]ccbar K(*)0 Decays PDF eBook
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Pages 15
Release 2009
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ISBN

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The authors present updated measurements of time-dependent Cp asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465 ± 5) x 106 [Upsilon](4S) 2!B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric energy ee− storage rings operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured from J/[psi] K{sub S}°, J/[psi]K{sub L}°, [psi](2S)K{sub S}°, [eta]{sub c}K{sub S}°, [chi]{sub c1}K{sub S}° and J/[psi] K*(892)° decays are: C{sub f} = 0.024 ± 0.020(stat) ± 0.016(syst) and -[eta]{sub f}S{sub f} = 0.687 ± 0.028(stat) ± 0.012(syst).

Measurement of Time-dependent CP Asymmetries InB0-]D(*)pi and B0-]Drho Decays

Measurement of Time-dependent CP Asymmetries InB0-]D(*)pi and B0-]Drho Decays
Title Measurement of Time-dependent CP Asymmetries InB0-]D(*)pi and B0-]Drho Decays PDF eBook
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Pages 8
Release 2006
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ISBN

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We present updated results on time-dependent CP asymmetries in fully reconstructed B° → D{sup (*)±}[pi]{sup {-+}} and B° → D{sup ±}[rho]{sup {-+}} decays in approximately 232 million [Upsilon](4S) → B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. From a time-dependent maximum likelihood fit we obtain for the parameters related to the CP violation angle 2[beta] + [gamma]: a{sup D{pi}} = -0.010 ± 0.023 ± 0.007, c{sub lep}{sup D{pi}} = -0.033 ± 0.042 ± 0.012, a{sup D*{pi}} = -0.040 ± 0.023 ± 0.010, C{sub lep}{sup D*{pi}} = 0.049 ± 0.042 ± 0.015, a{sup D{rho}} = -0.024 ± 0.031 ± 0.009, c{sub lep}{sup D{rho}} = -0.098 {+-} 0.055 {+-} 0.018, where the first error is statistical and the second is systematic. Using other measurements and theoretical assumptions, we interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle and find

Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR.

Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR.
Title Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR. PDF eBook
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Pages 355
Release 2007
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ISBN

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In this work we presented measurements of CP violation and decay rates of B decays in final states not involving a charm quark in the final state. In particular, the time-dependent CP asymmetries of decays which proceed through b 2!s elementary transition is a particularly sensitive probe of physics beyond the Standard Model. In fact, even if the precise measurements of CP conserving and CP violating processes show the success of the CKM picture of the flavour physics, the sector of b 2!s transitions is still not strongly constrained and leaves room for new physics contributions. In particular, we considered the decays which have the cleanest theoretical prediction within the Standard Model: B° 2![phi]K° and B° 2!K{sub s}°K{sub s}°K{sub s}° [beta]{sub eff}{sup SM} = 0.379. We examined the former with a completely new approach with respect to the past: the study of CP violation in the whole KK−K° phase space through a time-dependent Dalitz plot analysis. With this approach, we simultaneously measured the CP-violating asymmetries of the [phi]KJ°, f0(980)K° resonant and KK−K° non-resonant contributions, avoiding one of the largest uncertainties which affected the previous measurements of B° 2![phi]K°. We find [beta]{sub eff}(B° 2![phi]K°) = 0.06 ± 0.16 ± 0.05, which is lower than the Standard Model expectation, but it is consistent with it within two standard deviations. Moreover, only a recently developed experimental technique, which allows the determination of the position of B decay vertex when no charged tracks are originating from it, has made possible the measurement of the time-dependent CP asymmetry in B° 2!K{sub s}°K{sub s}°K{sub s}° decays. The mixing-induced CP parameter S in the Standard Model should be equal to sin 2[beta] parameter, which is measured with high precision in B 2![c{bar c}]K° decays by the B-factories. This statement is true, in the Standard Model, with excellent approximation for the decays studied in this work. The summary of the measurements in the b 2!s sector is shown in Fig. 9.8 A naive average of the b 2!s penguins, which does not account for the correlations existing among [phi]K°, f0(980)K° and K+K−K°, and that includes also modes with larger theoretical uncertainties, shows that -[eta]{sub CP} x S is lower than sin 2[beta]. This is not an evidence of physics beyond the Standard Model, but the systematic deviation from the expected value is an hint that there is room for it. More compelling evidence for new physics could be obtained measuring significant deviation in each decay channel from Standard Model prediction. Currently all the measurement are statistically limited and therefore an increase in accumulated statistics will shed more light into this quest for New Physics.

Measurement of Time-dependent CP Asymmetries in B^0 --] K^0_s K^0_s K^0_s Decays

Measurement of Time-dependent CP Asymmetries in B^0 --] K^0_s K^0_s K^0_s Decays
Title Measurement of Time-dependent CP Asymmetries in B^0 --] K^0_s K^0_s K^0_s Decays PDF eBook
Author B. Aubert
Publisher
Pages 17
Release 2006
Genre
ISBN

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The authors present an updated measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0} decays based on 347 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The authors obtain the CP asymmetries S{sub f} = -0.66 {+-} 0.26 {+-} 0.08 and C{sub f} = -0.14 {+-} 0.22 {+-} 0.05, where the first uncertainties are statistical and the second systematic.

Update of Time-Dependent CP Asymmetry Measurements in B to C-cbar-s Decays

Update of Time-Dependent CP Asymmetry Measurements in B to C-cbar-s Decays
Title Update of Time-Dependent CP Asymmetry Measurements in B to C-cbar-s Decays PDF eBook
Author
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Pages 19
Release 2008
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ISBN

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We present updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465 ± 5) x 106 [Upsilon](4S) → B{bar B} decays collected with the BABAR detector at the PEP-II B factory. The time-dependent CP asymmetry parameters measured from J/[psi]K{sub S}°, J/[psi]K{sub L}°, [psi](2S)K{sub S}°, [chi]{sub c1}K{sub S}°, [eta]{sub c}K{sub S}°, and J/[psi]K*° decays are: (1) C{sub f} = 0.026 ± 0.020(stat) ± 0.016(syst); and (2) S{sub f} = 0.691 ± 0.029(stat) ± 0.014(syst).