Search results for "Dalitz plot"
showing 10 items of 90 documents
Search for direct CP-violation in K±→π±π0π0 decays
2006
Abstract A search for direct CP-violation in K ± → π ± π 0 π 0 decay based on 47.14 million events has been performed by the NA48/2 experiment at the CERN SPS. The asymmetry in the Dalitz plot linear slopes A g = ( g + − g − ) / ( g + + g − ) is measured to be A g = ( 1.8 ± 2.6 ) × 10 −4 . The design of the experiment and the method of analysis provide good control of instrumental charge asymmetries in this measurement. The precision of the result is limited by statistics and is almost one order of magnitude better than that of previous measurements by other experiments.
Amplitude analysis and measurement of the time-dependentCPasymmetry ofB0→KS0KS0KS0decays
2012
We present the first results on the Dalitz-plot structure and improved measurements of the time-dependent CP-violation parameters of the process B0→KS0KS0KS0 obtained using 468×106 BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The Dalitz-plot structure is probed by a time-integrated amplitude analysis that does not distinguish between B0and B 0 decays. We measure the total inclusive branching fraction B(B0→KS0KS0KS0)=(6.19±0.48±0.15±0.12)×10-6, where the first uncertainty is statistical, the second is systematic, and the third represents the Dalitz-plot signal model dependence. We also observe evidence for the intermediate resonant states f0…
Observation and study of the baryonicB-meson decaysB→D(*)pp¯(π)(π)
2012
We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×106 BB pairs recorded by the BaBar detector at the SLAC PEP-II asymmetric-energy e^+e^- collider. The branching fractions are measured for the following ten decays: B ^0→D^0pp, B^0→D^(*0)pp, B^0→D^(*+)ppπ^-, B^0→D^(*+)ppπ^-, B-→D0ppπ^-, B-→D^(*0)ppπ^-, B^0→D^0pp π^-π^+, B^0→D^(*0)pp π^-π^+, B^-→D^+pp π^-π^-, and B^-→D^(*+)pp π^-π^-. The four B^- and the two five-body B^0 modes are observed for the first time. The four-body modes are enhanced compared to the three- and the five-body modes. In the three-body modes, the M(pp) and M(D^((*)0)p) invariant-mass distributions show enhancements near thre…
Measurements ofCPviolation in the three-body phase space of charmlessB±decays
2014
The charmless three-body decay modes B±→K±π+π−, B±→K±K+K−, B±→π±K+K− and B±→π±π+π− are reconstructed using data, corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb detector. The inclusive CP asymmetries of these modes are measured to be ACP(B±→K±π+π−)=+0.025±0.004±0.004±0.007,ACP(B±→K±K+K−)=−0.036±0.004±0.002±0.007,ACP(B±→π±π+π−)=+0.058±0.008±0.009±0.007,ACP(B±→π±K+K−)=−0.123±0.017±0.012±0.007, where the first uncertainty is statistical, the second systematic, and the third is due to the CP asymmetry of the B±→J/ψK± reference mode. The distributions of these asymmetries are also studied as functions of position in the Dalitz plot and suggest contributions from res…
Amplitude analysis of the decayD0→K−K+π0
2007
Using 385 fb^-1 of e^+e^- collisions at the CM energies of around 10.6 GeV recorded by the BaBar experiment, we study the amplitudes of the singly Cabibbo-suppressed decay D^0 --> K^- K^+ pi^0. We measure the strong phase difference between the D0bar and D0 decays to the K^*(892)^+ K^- state to be -35.5 +/- 1.9 (stat) +/- 2.2 (syst) degrees, and their amplitude ratio to be 0.599 +/- 0.013 (stat) +/- 0.011 (syst). We observe significant contributions from the Kpi and K^-K^+ scalar and vector amplitudes, and analyze the moments of the cosine of the helicity angle in these systems. We find no evidence for charged, scalar kappa(800) state, nor for higher spin states. We also perform a model-ind…
Amplitude analysis ofB0→K+π−π0and evidence of directCPviolation inB→K*πdecays
2011
We analyze the decay B0-->K+ pi- pi0 with a sample of 454 million B Bbar events collected by the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC, and extract the complex amplitudes of seven interfering resonances over the Dalitz plot. These results are combined with amplitudes measured in B0-->K_S pi+ pi- decays to construct isospin amplitudes from B0-->K* pi and B0-->rho K decays. We measure the phase of the isospin amplitude Phi_3/2, useful in constraining the CKM unitarity triangle angle gamma and evaluate a CP rate asymmetry sum rule sensitive to the presence of new physics operators. We measure direct CP violation in B0-->K*+ pi- decays at the level of 3 sigma when mea…
Measurements ofe+e−→K+K−η,K+K−π0, andKs0K±π∓cross sections using initial state radiation events
2008
This paper reports measurements of processes: e+e-→γKS0K±π∓, e+e-→γK+K-π0, e+e-→γϕη, and e+e-→γϕπ0. The initial-state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ≈4.6 GeV. The overall size of the data sample analyzed is 232 fb-1, collected by the BABAR detector running at the PEP-II e+e- storage ring. From the Dalitz plot analysis of the KS0K±π∓ final state, moduli, and relative phase of the isoscalar and the isovector components of the e+e-→KK*(892) cross section are determined. Parameters of ϕ and ρ recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli, and phases…
Photoproduction of neutral pion pairs from the proton
2000
Double neutral pion photoproduction from the proton has been measured at MAMI for photon energies between threshold and 820 MeV. The reaction was identified by an invariant mass and missing mass analysis. From threshold up to 370 MeV the total cross-section does not exceed 30 nb. For higher energies it shows a smooth rise until it reaches a maximum of about 10 μb at Eγ = 740 MeV. Dalitz plots of m2(π0π0) versusm2(p,π0) for seven bins of incident photon energy have been analysed. For Eγ > 610 MeV, a strong contribution of a sequential decay is observed with the Δ(1232)-resonance as intermediate state. A comparison to model calculations shows that these sequential decays presumably originate …
Constraints on the CKM angleγinB0→D¯0K*0andB0→D0K*0from a Dalitz analysis ofD0andD¯0decays toKSπ+π−
2009
We present constraints on the angle γ of the unitarity triangle with a Dalitz analysis of neutral D decays to KSπ+π- from the processes B0→D0K*0 (B0→D0K*0) and B0→D0K*0 (B0→D0K*0) with K*0→K+π- (K*0→K-π+). Using a sample of 371×106 BB pairs collected with the BABAR detector at PEP-II, we constrain the angle γ as a function of rS, the magnitude of the average ratio between b→u and b→c amplitudes. © 2009 The American Physical Society.
Measurement of the Dalitz plot slope parameters of the K±→π±π+π− decay
2007
Abstract The distribution of the K ± → π ± π + π − decays in the Dalitz plot has been measured by the NA48/2 experiment at the CERN SPS with a sample of 4.71 × 10 8 fully reconstructed events. With the standard Particle Data Group parameterization the following values of the slope parameters were obtained: g = ( − 21.134 ± 0.017 ) % , h = ( 1.848 ± 0.040 ) % , k = ( − 0.463 ± 0.014 ) % . The quality and statistical accuracy of the data have allowed an improvement in precision by more than an order of magnitude, and are such as to warrant a more elaborate theoretical treatment, including pion–pion rescattering, which is in preparation.