共查询到20条相似文献,搜索用时 0 毫秒
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Dong-Sheng Du 《The European Physical Journal C - Particles and Fields》2007,50(3):579-584
The CP asymmetries for the decays of the neutral charmed meson into CP eigenstates are carefully studied. Formulas and numerical
results are presented. The impact on experiments is briefly discussed. 相似文献
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Abe K Abe K Abe R Adachi I Ahn BS Aihara H Akatsu M Alimonti G Asai K Asai M Asano Y Aso T Aulchenko V Aushev T Bakich AM Banas E Behari S Behera PK Beiline D Bondar A Bozek A Browder TE Casey BC Chang P Chao Y Chen KF Cheon BG Chistov R Choi SK Choi Y Dong LY Dragic J Drutskoy A Eidelman S Eiges V Enari Y Enomoto R Everton CW Fang F Fujii H Fukunaga C Fukushima M Gabyshev N Garmash A Gershon TJ Gordon A Gotow K Guler H Guo R Haba J Hamasaki H Hanagaki K Handa F Hara K Hara T Hastings NC 《Physical review letters》2001,87(9):091802
We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system. 相似文献
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He XG 《Physical review D: Particles and fields》1996,53(11):6326-6333
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There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely
factorization, QCD factorization and the perturbative QCD approach based on k
T factorization, using new parameters and full wave functions. Although they get similar results for many of the branching
ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements
of B factories. 相似文献
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We comment on CP, T and CPT violation in the light of interesting new data from the CPLEAR and KTeV Collaborations on neutral kaon decay asymmetries. Other recent data from the CPLEAR experiment, constraining possible violations of CPT and the ΔS=ΔQ rule, exclude the possibility that the semileptonic-decay asymmetry AT measured by CPLEAR could be solely due to CPT violation, confirming that their data constitute direct evidence for T violation. The CP-violating asymmetry in KL→e−e+π−π+ recently measured by the KTeV Collaboration does not by itself provide direct evidence for T violation, but we use it to place new bounds on CPT violation. 相似文献
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W. Bernreuther U. Löw J. P. Ma O. Nachtmann 《Zeitschrift fur Physik C Particles and Fields》1989,43(1):117-132
We present a general discussion ofCP-violating effects in the following two and three body decays of theZ boson:Z→l + l ?,Z→l + l ?γ, wherel=e, μ, τ andZ→2 jets,Z→ 2 jets+γ, andZ→ 3 jets. Experimental observables sensitive toCP violation in these decays are discussed systematically for the case that polarizations of final state particles are not observed. It is shown that the standard model predicts only extremely smallCP-violating effects for the above decays. PossibleCP-violating interactions beyond the standard model are parametrized in terms of aCP-odd effective Lagrangian containing coupling constants proportional to Λ P -1 and Λ P -2 . Here Λ CP is the mass scale associated with the assumed new interactions. We give estimates of the bounds obtainable for Λ CP in experiments at LEP1. 相似文献
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Aubert B Bona M Boutigny D Karyotakis Y Lees JP Poireau V Prudent X Tisserand V Zghiche A Garra Tico J Grauges E Lopez L Palano A Eigen G Ofte I Stugu B Sun L Abrams GS Battaglia M Brown DN Button-Shafer J Cahn RN Groysman Y Jacobsen RG Kadyk JA Kerth LT Kolomensky YG Kukartsev G Lopes Pegna D Lynch G Mir LM Orimoto TJ Pripstein M Roe NA Ronan MT Tackmann K Wenzel WA Del Amo Sanchez P Hawkes CM Watson AT Held T Koch H Lewandowski B Pelizaeus M Schroeder T Steinke M Cottingham WN Walker D 《Physical review letters》2007,99(17):171803
We present updated measurements of time-dependent CP asymmetries in fully-reconstructed neutral B decays to several CP eigenstates containing a charmonium meson. The measurements use a data sample of (383+/-4)x10(6) Upsilon(4S)-->BB[over] decays collected with the BABAR detector at the PEP-II B factory. We determine sin2beta = 0.714+/-0.032(stat)+/-0.018(syst) and |lambda|=0.952+/-0.022(stat)+/-0.017(syst). 相似文献
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We investigate how to testCP invariance in the weak decay of top quarks. A prediction ofCP violation from the Standard Model is made by an explicit calculation. The effect is very small as expected. We then use a form factor approach to parametrize possible new interactions ofCP violation. The differences between the form factor approach and an effective Lagrangian approach are discussed. The sensitivity of ourCP-odd observables to the form factors is estimated. 相似文献
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Gronau M 《Physical review letters》1989,63(14):1451-1454