CP-violation Parameters In B0 Research Articles

Measurement of time-dependent CP violation parameters in B0→KS0KS0KS0 decays at Belle

We measure the time-dependent CP violation parameters in B0→KS0KS0KS0 decays using 772×106BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The obtained mixing-induced and direct CP asymmetries are −0.71±0.23 (stat)±0.05 (syst) and 0.12±0.16 (stat)±0.05 (syst), respectively. These values are consistent with the Standard Model predictions. The significance of CP violation differs from zero by 2.5 standard deviations.Received 3 November 2020Accepted 15 January 2021DOI:https://doi.org/10.1103/PhysRevD.103.032003Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsBottom mesonsQuark mixingTechniquesLepton collidersParticle decaysParticle mixing & oscillationsParticles & Fields

B-meson decays into charmonium states in the ATLAS experiment

The paper presents several recent ATLAS results on the analyses of B-meson decays into charmonium states. These include the measurements of B+ mass and the fractions of J/ψ mesons produced in b-hadron decays in pp collisions at $$\sqrt s$$ = 13 TeV in the center of mass system. The measured partial widths and polarizations in B + → J/ψD (*)+ decays and CP-violation parameters in B 0 → J/ψϕ decays in pp collisions at 7 and 8 TeV in the center of mass system are also presented.

Constraining the UT angle γ by CP violation parameters in B0 → π+π−**Partly Supported by National Science Foundation of China (11175151, 11235005, 11375208, 11447032, 11575151), Natural Science Foundation of Shandong Province (ZR2014AQ013) and the Program for New Century Excellent Talents in University (NCET) by Ministry of Education of P.R. China (NCET-13-0991)

We calculate the tree and penguin amplitudes in the B0 → π+π− decay channel employing the perturbative QCD factorization approach. Using the amplitudes as input with the theoretical uncertainties sufficiently considered, we constrain the UT angle γ to 53° ⩽ γ ⩽ 70°, from the measurements of the CP violation parameters Cπ+π− and Sπ+π− in B0 → π+π−. The U-spin breaking effect between B0 → π+π− and is estimated to be around 30%.

CP violation in B decays at Belle

Using the full data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider, we present three recent measurements of time-dependent CP violation in B decays that are sensitive to potential new physics contributions and a measurement of branching fraction of the B0 → π0π0 decay. We studied B → ωK decays and measured the values of CP violation parameters in B0 → ωK0S to be AωK0S = 0.36 ± 0.19 ± 0.05 and SωK0S = +0.91 ± 0.32 ± 0.05, which gives the first evidence of CP violation in this decay. From the measurement of CP violation parameters in the B0 → η'K0 decay we obtain Sη'K0 = 0.68 ± 0.07 ± 0.03 and Aη'K0 = +0.03 ± 0.05 ± 0.04, which are the world's most precise values to date. We present the Belle first measurement of CP violation parameters in B0 → K0Sηγ decay, where we measure SK0Sηγ = -1.32 ± 0.77 ± 0.36 and AK0Sηγ = -0.48 ± 0.41 ± 0.07 (preliminary). Finally we present our preliminary measurement of the B0 → π0π0 branching fraction. We measure B(B0 → π0π0) = (0.89 ± 0.12 ± 0.10) × 10-6, with significantly improved sensitivity compared to previously available results.

Measurement of branching fraction and first evidence ofCPviolation inB0→a1±(1260)π∓decays

We present a measurement of the branching fraction and time-dependent CP violation parameters in B0 --> a_1^+-(1260) pi^-+ decays. The results are obtained from the final data sample containing 772x10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We also measure an upper limit on the product branching fraction for a possible decay with the same final state B0 --> a_2^+-(1320) pi^-+. In a time-dependent measurement to extract CP asymmetries, we find evidence of mixing-induced CP violation in B0 --> a_1^+-(1260) pi^-+ decays with a 3.1 sigma significance and the rate where the a_1^+-(1260) does not contain the spectator quark is found to dominate the rate where it does at the 4.1 sigma level. However, there is no evidence for either time and flavor integrated direct CP violation or flavor-dependent direct CP violation.

Time-dependent Dalitz plot measurement ofCPparameters inB0→KS0π+π−decays

We present a time-dependent Dalitz plot measurement of CP violation parameters in B0 --> Ks Pi+ Pi- decays. These results are obtained from a large data sample that contains 657 million BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. For the CP violation parameters, we obtain two consistent solutions that describe the data well. The first of these solutions may be preferred by external information from other measurements. There is no evidence for direct CP violation in B0 --> rho0(770) Ks, B0 --> f0(980) Ks and B0 --> K*+(892) Pi-, while measurements of mixing-induced CP violation in B0 --> rho0(770) Ks, B0 --> f0(980) Ks decays are consistent with that of b --> c cbar s decays. We also measured the phase difference between B0 --> K*+(892) Pi- and B0B --> K*-(892) Pi+ which may be used to extract phi3.

Time dependent CP violation in penguin dominated B decays

We present a measurement of the CP violation parameters in B0 → KS0π0π0 and B0 → KS0KS0 decays using a data sample containing 657 × 106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e− collider operating at the γ(4S) resonance. We obtain S κπ0π0 = +0.43 ± 0.49 ± 0.09, Aκπ0π0 = -0.17 ± 0.24 ± 0.06, Sκs0κ0 = -0.38 ± 0.77 ± 0.08 and Aκs0κ0 = -0.38 ± 0.38 ± 0.05, where the first and second errors are statistical and systematic, respectively.

Observation of Time-DependentCPViolation inB0→η′K0Decays and Improved Measurements ofCPAsymmetries inB0→φK0,KS0KS0KS0andB0→J/ψK0Decays

We present improved measurements of CP-violation parameters in B0→ϕK0, η′K0, KS0KS0KS0 decays based on a sample of 535×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e− collider. We obtain sin2ϕ1eff=+0.64±0.10(stat)±0.04(syst) for B0→η′K0, +0.50±0.21(stat)±0.06(syst) for B0→ϕK0, and +0.30±0.32(stat)±0.08(syst) for B0→KS0KS0KS0 decays. We have observed CP violation in the B0→η′K0 decay with a significance of 5.6 standard deviations. We also perform an improved measurement of CP asymmetries in B0→J/ψK0 decays and obtain sin2ϕ1=+0.642±0.031(stat)±0.017(syst).Received 2 October 2006DOI:https://doi.org/10.1103/PhysRevLett.98.031802©2007 American Physical Society

Time-dependentCP-violating asymmetries inb→sq¯qtransitions

We present new measurements of CP-violation parameters in B0→ϕK0, K+K−KS0, f0(980)KS0, η′KS0, ωKS0, and KS0π0 decays based on a sample of 275×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e− collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the decay modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. The combined result for the B0→ϕK0, K+K−KS0, f0(980)KS0, η′KS0, ωKS0, KS0π0, and previously reported KS0KS0KS0 decays differs from the SM expectation by 2.4 standard deviations.Received 12 April 2005DOI:https://doi.org/10.1103/PhysRevD.72.012004©2005 American Physical Society

CP Violation in b → s Decays and New Physics Phases

We present new measurements of CP-violation parameters in B0 → ϕK0, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] decays based on a sample of [Formula: see text] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the decay modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. All results are preliminary.

Measurement of time-dependent CP-violating asymmetries in B0-->phiK(0)S, K+K-K0(S), and eta'K0(S) decays.

We present an improved measurement of CP-violation parameters in B0-->phiK(0)(S), K(+)K(-)K(0)(S), and eta(')K(0)(S) decays based on a 140 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the three modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. We find that the observed CP asymmetry in the B-->phiK(0)(S) decay differs from the standard model (SM) expectation by 3.5 standard deviations, while the other cases are consistent with the SM.