101 research outputs found
Evidence for Direct CP Violation in B0 -> K+- pi-+ Decays
We report evidence for direct CP violation in the decay B0 -> K+-pi-+ with
253/fb of data collected with the Belle detector at the KEKB e+e- collider.
Using 275 million B B_bar pairs we observe a B -> K+-pi-+ signal with 2140+-53
events. The measured CP violating asymmetry is Acp(K+-pi-+) = -0.101+-0.025
(stat)+-0.005 (syst), corresponding to a significance of 3.9 sigma including
systematics. We also search for CP violation in the decays B+- -> K+-pi0 and
B+- -> pi+-pi0. The measured CP violating asymmetries are Acp(K+-pi0) =
0.04+-0.05(stat)+-0.02(syst) and Acp(pi+-pi0) = -0.02+-0.10(stat)+-0.01(syst),
corresponding to the intervals -0.05 < Acp(K+-pi0) < 0.13 and
-0.18<Acp(pi+-pi0)<0.14 at 90% confidence level.Comment: 9 pages, 3 figures. submitted to Physical Review Letter
An Improved Measurement of Mixing-induced CP Violation in the Neutral B Meson System
We present an improved measurement of the standard model CP violation
parameter sin2phi_1 (also known as sin2beta) based on a sample of 85 times 10^6
B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at
the KEKB asymmetric-energy e+e- collider. One neutral B meson is reconstructed
in a J/psi K_S, psi(2S) K_S, chi_{c1} K_S, eta_c K_S, J/psi K^{*0}, or J/psi
K_L CP-eigenstate decay channel and the flavor of accompanying B meson is
identified from itsdecay products. From the asymmetry in the distribution of
the time intervals between the two B meson decay points, we obtain sin2phi_1 =
0.719 +/- 0.074(stat) +/- 0.035(syst). We also report measurements of CP
violation parameters for the related B^0 -> J/psi pi^0 decay mode and the
penguin-dominated processes B^0 -> eta' K_S, phi K_S and K^+K^- K_S.Comment: 11 pages, 4 figures, 4 tables, contributed to ICHEP200
Angular analysis of
We present a measurement of angular observables, , , ,
, in the decay , where
is either or . The analysis is performed on
a data sample corresponding to an integrated luminosity of
containing pairs, collected
at the resonance with the Belle detector at the
asymmetric-energy collider KEKB. Four angular observables,
are extracted in five bins of the invariant mass squared of the
lepton system, . We compare our results for with Standard
Model predictions including the region in which the LHCb collaboration
reported the so-called anomaly.Comment: Conference paper for LHC Ski 2016. SM prediction for
corrected and reference for arXiv:1207.2753 adde
- …