38 research outputs found
Measurements of CP-Violating Asymmetries in the Decay B^{0}âK^{+}K^{-}K^{0}
We analyze the decay B0âK+K-K0 using 383Ă106 BBÌ
events collected by the BABAR detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K+K-K0 events, we find ACP=-0.015±0.077±0.053 and ÎČeff=0.352±0.076±0.026âârad, corresponding to a CP violation significance of 4.8Ï. A second solution near Ï/2-ÎČeff is disfavored with a significance of 4.5Ï. We also report ACP and ÎČeff separately for decays to Ï(1020)K0, f0(980)K0, and K+K-K0 with mK+K->1.1ââGeV/c2
Measurement of the time-dependent CP asymmetry in B0âDCP(*)h0 decays
We report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B-0 -> D((*)0)h(0) decays, where h(0) is a pi(0), eta, or omega meson, and the decays to one of the CP eigenstates K+K-, K-S(0)pi(0), or K-S(0)omega. The data sample consists of 383x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The results are S=-0.56 +/- 0.23 +/- 0.05 and C=-0.23 +/- 0.16 +/- 0.04, where the first error is statistical and the second is systematic
Branching fraction measurements of B+âÏ+Îł, B0âÏ0Îł, and B0âÏÎł
We present a study of the decays B+->rho(+)gamma, B-0 ->rho(0)gamma, and B-0 ->omega gamma. The analysis is based on data containing 347x10(6) B (B) over bar events recorded with the BABAR detector at the PEP-II asymmetric B factory. We measure the branching fractions B(B+->rho(+)gamma)=(1.10(-0.33)(+0.37)+/- 0.09)x10(-6) and B(B-0 ->rho(0)gamma)=(0.79(-0.20)(+0.22)+/- 0.06)x10(-6), and set a 90% C.L. upper limit B(B-0 ->omega gamma)(rho/omega)gamma)=(1.25(-0.24)(+0.25)+/- 0.09)x10(-6), from which we determine vertical bar V-td/V-ts vertical bar=0.200(-0.020)(+0.021)+/- 0.015, where the first uncertainty is experimental and the second is theoretical
Measurement of cos2ÎČ in B0âD(*)h0 decays with a time-dependent Dalitz plot analysis of DâKs0Ï+Ï-
We study the time-dependent Dalitz plot of D -> K-S(0)pi(+) pi(-) in B-0 -> D((*))h(0) decays, where h(0) is a pi(0), eta, eta', or omega meson and D-* -> D pi(0), using a data sample of 383 x 10(6) Upsilon(4S) -> B (B) over bar decays collected with the BABAR detector. We determine cos2 beta = 0.42 +/- 0.49 +/- 0.09 +/- 0.13, sin2 beta = 0.29 +/- 0.34 +/- 0.03 +/- 0.05, and |lambda| = 1.01 +/- 0.08 +/- 0.02, where the first error is statistical, the second is the experimental systematic uncertainty, and the third, where given, is the Dalitz model uncertainty. Assuming the world average value for sin2 beta and |lambda| = 1, cos2 beta > 0 is preferred over cos2 beta < 0 at 86% confidence level
Search for the decay B+-> K+tau(-/+)mu(+/-)
We present a search for the lepton flavor violating decay B+-> K+tau(-/+)mu(+/-) using 383x10(6) B (B) over bar events collected by the BABAR experiment. The branching fraction for this decay can be substantially enhanced in new physics models. The kinematics of the tau from the signal B decay are inferred from the K+, mu, and other B in the event, which is fully reconstructed in one of a variety of hadronic decay modes, allowing the signal B candidate to be fully reconstructed. We observe no excess of events over the expected background and set a limit of B(B+-> K+tau mu)< 7.7x10(-5) at 90% confidence level, where the branching fraction is for the sum of the K+tau(-)mu(+) and K+tau(+)mu(-) final states. We use this result to improve a model-independent bound on the energy scale of flavor-changing new physics
Observation of B meson decays to b(1)pi and b(1)K
We present the results of searches for decays of B mesons to final states with a b(1) meson and a charged pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 382x10(6) B(B)over bar pairs produced in e(+)e(-) annihilation. The results for the branching fractions are, in units of 10(-6), B(B+ -> b(1)(0)pi(+)) = 6.7 +/- 1.7 +/- 1.0, B(B+ -> b(1)(0)K(+)) = 9.1 +/- 1.7 +/- 1.0, B(B-0 -> b(1)(-/+)pi +/- ) = 10.9 +/- 1.2 +/- 0.9, and B(B-0 -> b(1)(-)K(+)) = 7.4 +/- 1.0 +/- 1.0, with the assumption that B(b(1) -> omega pi) = 1. We also measure charge and flavor asymmetries A(ch)(B+ -> b(1)(0)pi(+)) = 0.05 +/- 0.16 +/- 0.02, A(ch)(B+ -> b(1)(0)K(+)) = -0.46 +/- 0.20 +/- 0.02, A(ch)(B-0 -> b(1)(-/+)pi +/- ) = -0.05 +/- 0.10 +/- 0.02, C(B-0 -> b(1)(-/+)pi +/- ) = -0.22 +/- 0.23 +/- 0.05, Delta C(B-0 -> b(1)(-/+)pi +/- ) = -1.04 +/- 0.23 +/- 0.08, and A(ch)(B-0 -> b(1)(-)K(+)) = -0.07 +/- 0.12 +/- 0.02. The first error quoted is statistical, and the second systematic
Amplitude analysis of the decay D0âK-K+Ï0
Using 385 fb(-1) of e(+)e(-) collisions, we study the amplitudes of the singly Cabibbo-suppressed decay D-0 -> K-K+pi(0). We measure the strong phase difference between the (D) over bar (0) and D-0 decays to K-*(892)K-+(-) to be -35.5 degrees +/- 1.9 degrees(stat)+/- 2.2 degrees(syst), and their amplitude ratio to be 0.599 +/- 0.013(stat)+/- 0.011(syst). We observe contributions from the K pi and K-K+ scalar and vector amplitudes, and analyze their angular moments. We find no evidence for charged kappa, nor for higher spin states. We also perform a partial-wave analysis of the K-K+ system in a limited mass range
Observation of Decays and
7 pages, 2 postscript figues, submitted to Physical Review Letters - P. Grenier aussi au LPCWe report the observation of decays B0->D_s(*)+pi- and B0->D_s(*)-K+ in a sample of 230*10^6 Upsilon(4S)->BBbar events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- storage ring. We measure the branching fractions B(B0->D_s+pi-)=(1.3 +/- 0.3 (stat.) +/- 0.2 (syst.))*10^{-5}, B(B0->D_s-K+)=(2.5 +/- 0.4 (stat.) +/- 0.4 (syst.))*10^{-5}, B(B0->D_s*+pi-)=(2.8 +/- 0.6 (stat.) +/- 0.5 (syst.))*10^{-5}, and B(B0->D_s*-K+)=(2.0 +/- 0.5 (stat.) +/- 0.4 (syst.))*10^{-5}. The significance of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively
Study of B0âÏ+Ï- decays and constraints on the CKM angle α
We present results from an analysis of B-0 ->rho(+)rho(-) decays using (383.6 +/- 4.2)x10(6) B (B) over bar pairs collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The measurements of the B-0 ->rho(+)rho(-) branching fraction, longitudinal polarization fraction f(L), and the CP-violating parameters S-long and C-long are as follows: B(B-0 ->rho(+)rho(-))=(25.5 +/- 2.1(stat)(-3.9)(+3.6)(syst))x10(-6), f(L)=0.992 +/- 0.024(stat)(-0.013)(+0.026)(syst), S-long=-0.17 +/- 0.20(stat)(-0.06)(+0.05)(syst), C-long=0.01 +/- 0.15(stat)+/- 0.06(syst). We determine the unitarity triangle angle alpha, using an isospin analysis of B ->rho rho decays. One of the two solutions, alpha=[73.1,117.0]degrees at 68% confidence level, is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry-based approach
Evidence for the B-0 -> p(p)over-barK*(0) and B+->eta K-c*(+) decays and study of the decay dynamics of B meson decays into p(p)over-barh final states
With a sample of 232x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector, we study the decays of B mesons to p (p) over barh final states, where h=pi(+), K-S(0), K*(0), or K*(+). We report evidence for the B-0 -> p (p) over barK(*0) decay, with a branching fraction (1.47 +/- 0.45(stat)+/- 0.40(syst))x10(-6), and for the B+->eta K-c*(+) decay, with the branching fraction of B(B+->eta K-c*(+))xB(eta(c)-> p (p) over bar)=(1.57(-0.45)(+0.56)(stat)(-0.36)(+0.46)(syst))x10(-6), and provide improved measurements of the branching fractions of the other modes of this type. We also report the measurements of the charge asymmetry consistent with zero in the B+-> p (p) over bar pi(+), B-0 -> p (p) over barK*(0), and B+-> p (p) over barK*(+) modes. No evidence is found for the pentaquark candidate Theta(+) in the mass range 1.52 to 1.55 GeV/c(2), decaying into pK(S)(0), or the glueball candidate f(J)(2220) in the mass range 2.2 < m(p (p) over bar)< 2.4 GeV/c(2), and branching fraction limits are established for both at the 10(-7) level