Publications (524)2509.6 Total impact
 [Show abstract] [Hide abstract]
ABSTRACT: We report a measurement of the timedependent CP asymmetry of B0>D(*)CP h0 decays, where the light neutral hadron h0 is a pi0, eta or omega meson, and the neutral D meson is reconstructed in the CP eigenstates K+ K, K0S pi0 or K0S omega. The measurement is performed combining the final data samples collected at the Y(4S) resonance by the BaBar and Belle experiments at the asymmetricenergy B factories PEPII at SLAC and KEKB at KEK, respectively. The data samples contain ( 471 +/ 3 ) x 10^6 BB pairs recorded by the BaBar detector and ( 772 +/ 11 ) x 10^6, BB pairs recorded by the Belle detector. We measure the CP asymmetry parameters eta_f S = +0.66 +/ 0.10 (stat.) +/ 0.06 (syst.) and C = 0.02 +/ 0.07 (stat.) +/ 0.03 (syst.). These results correspond to the first observation of CP violation in B0>D(*)CP h0 decays. The hypothesis of no mixinginduced CP violation is excluded in these decays at the level of 5.4 standard deviations.  [Show abstract] [Hide abstract]
ABSTRACT: We present a search for a neutral, longlived particle L that is produced in e^{+}e^{} collisions and decays at a significant distance from the e^{+}e^{} interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an e^{+}e^{} data sample with a luminosity of 489.1 fb^{1} collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the twotrack mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible twobody L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction B(B→X_{s}L), where X_{s} is a strange hadronic system.  [Show abstract] [Hide abstract]
ABSTRACT: We present a measurement of the asymmetry A_{CP} between samesign inclusive dilepton samples ℓ^{+}ℓ^{+} and ℓ^{}ℓ^{} (ℓ=e, μ) from semileptonic B decays in ϒ(4S)→BB[over ¯] events, using the complete data set recorded by the BABAR experiment near the ϒ(4S) resonance, corresponding to 471×10^{6} BB[over ¯] pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B[over ¯]^{0}→B^{0}) and P(B^{0}→B[over ¯]^{0}), and therefore probes CP and T violation. The result, A_{CP}=[3.9±3.5(stat)±1.9(syst)]×10^{3}, is consistent with the standard model expectation. 
Article: The Physics of the B Factories
[Show abstract] [Hide abstract]
ABSTRACT: This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C. Please note that version 3 on the archive is the auxiliary version of the Physics of the B Factories book. This uses the notation alpha, beta, gamma for the angles of the Unitarity Triangle. The nominal version uses the notation phi_1, phi_2 and phi_3. Please cite this work as Eur. Phys. J. C74 (2014) 3026.  [Show abstract] [Hide abstract]
ABSTRACT: Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the socalled dark photon (A^{'}), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e^{+}e^{}→γA^{'}, A^{'}→e^{+}e^{}, μ^{+}μ^{} using 514 fb^{1} of data collected with the BABAR detector. We observe no statistically significant deviations from the standard model predictions, and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10^{4}10^{3} for dark photon masses in the range 0.0210.2 GeV. We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.  [Show abstract] [Hide abstract]
ABSTRACT: We describe searches for B meson decays to the charmless vectorvector final states omega omega and omega phi with 471 x 10^6 B Bbar pairs produced in e+ e annihilation at sqrt(s) = 10.58 GeV using the BABAR detector at the PEPII collider at the SLAC National Accelerator Laboratory. We measure the branching fraction B(B0 > omega omega) = (1.2 + 0.3 +0.30.2) x 10^6, where the first uncertainty is statistical and the second is systematic, corresponding to a significance of 4.4 standard deviations. We also determine the upper limit B(B0 > omega phi) < 0.7 x 10^6 at 90% confidence level. These measurements provide the first evidence for the decay B0 > omega omega, and an improvement of the upper limit for the decay B0 > omega phi.  [Show abstract] [Hide abstract]
ABSTRACT: We present results of a search for CP violation in B^{0} B[over ¯]^{0} mixing with the BABAR detector. We select a sample of B^{0}→D^{*}Xℓ^{+}ν decays with a partial reconstruction method and use kaon tagging to assess the flavor of the other B meson in the event. We determine the CP violating asymmetry A_{CP}≡[N(B^{0}B^{0})N(B[over ¯]^{0}B[over ¯]^{0})]/[N(B^{0}B^{0})+N(B[over ¯]^{0}B[over ¯]^{0})]=(0.06±0.17_{0.32}^{+0.38})%, corresponding to Δ_{CP}=1q/p=(0.29±0.84_{1.61}^{+1.88})×10^{3}.  [Show abstract] [Hide abstract]
ABSTRACT: We report results of a search for Weakly Interacting Massive Particles (WIMPs) with the Si detectors of the CDMS II experiment. This report describes a blind analysis of the first data taken with CDMS II's full complement of detectors in 20062007; results from this exposure using the Ge detectors have already been presented. We observed no candidate WIMPscattering events in an exposure of 55.9 kgdays before analysis cuts, with an expected background of ~1.1 events. The exposure of this analysis is equivalent to 10.3 kgdays over a recoil energy range of 7100 keV for an ideal Si detector and a WIMP mass of 10 GeV/c2. These data set an upper limit of 1.7x1041 cm2 on the WIMPnucleon spinindependent cross section of a 10 GeV/c2 WIMP. These data exclude parameter space for spinindependent WIMPnucleon elastic scattering that is relevant to recent searches for lowmass WIMPs.  [Show abstract] [Hide abstract]
ABSTRACT: We report the determination of the CabibboKobayashiMaskawa CPviolating angle gamma through the combination of various measurements involving B+/ > DK +/, B+/ > D*K+/, and B+/ > DK*(+/) decays performed by the BABAR experiment at the PEPII e(+)e() collider at SLAC National Accelerator Laboratory. Using up to 474 million B (B) over bar pairs, we obtain gamma = (69(16)(+17))degrees modulo 180 degrees. The total uncertainty is dominated by the statistical component, with the experimental and amplitudemodel systematic uncertainties amounting to +/ 4 degrees. The corresponding twostandarddeviation region is 41 degrees < gamma < 102 degrees. This result is inconsistent with gamma = 0 with a significance of 5.9 standard deviations.  [Show abstract] [Hide abstract]
ABSTRACT: We report on a search for direct $CP$ violation in the singly Cabibbosuppressed decay ${D}^{+}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{}}{\ensuremath{\pi}}^{+}$ using a data sample of $476\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{}1}$ of ${e}^{+}{e}^{\ensuremath{}}$ annihilation data accumulated with the BABAR detector at the SLAC PEPII electronpositron collider, running at and just below the energy of the $\ensuremath{\Upsilon}(4S)$ resonance. The integrated $CP$violating decay rate asymmetry ${A}_{CP}$ is determined to be $(0.37\ifmmode\pm\else\textpm\fi{}0.30\ifmmode\pm\else\textpm\fi{}0.15)%$. Modelindependent and modeldependent Dalitz plot analysis techniques are used to search for $CP$violating asymmetries in the various intermediate states. We find no evidence for $CP$violation asymmetry.  [Show abstract] [Hide abstract]
ABSTRACT: We present improved measurements of CPviolation parameters in the decays B0→π+π, B0→K+π, and B0→π0π0, and of the branching fractions for B0→π0π0 and B0→K0π0. The results are obtained with the full data set collected at the Υ(4S) resonance by the BABAR experiment at the PEPII asymmetricenergy B factory at the SLAC National Accelerator Laboratory, corresponding to (467±5)×106 BB̄ pairs. We find the CPviolation parameter values and branching fractions: Sπ+π= 0.68±0.10±0.03, Cπ+π=0.25±0.08±0. 02, AKπ+=0.107±0.0160.004+0.006, C π0π0=0.43±0.26±0.05, B(B0→π0π0)=(1. 83±0.21±0.13)×106, B(B0→K0π0)=(10. 1±0.6±0.4)×106, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B0→π+π and 6.1 standard deviations for B0→K+π, including systematic uncertainties. Constraints on the unitarity triangle angle α are determined from the isospin relations among the B→ππ rates and asymmetries. Considering only the solution preferred by the Standard Model, we find α to be in the range [71, 109] at the 68% confidence level.  [Show abstract] [Hide abstract]
ABSTRACT: We use 429 fb1 of e+e collision data collected at the Υ(4S) resonance with the BABAR detector to measure the radiative transition rate of b→sγ with a sum of 38 exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be B(B̅ →Xsγ)=(3.29±0.19±0.48)×104 where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the bestfit values for the heavyquark parameters, mb and μπ2, in the kinetic and shape function models.  [Show abstract] [Hide abstract]
ABSTRACT: We study the process e+e→J/ψπ+π with initialstateradiation events produced at the PEPII asymmetricenergy collider. The data were recorded with the BABAR detector at centerofmass energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454 fb1. We investigate the J/ψπ+π mass distribution in the region from 3.5 to 5.5 GeV/c2. Below 3.7 GeV/c2 the ψ(2S) signal dominates, and above 4 GeV/c2 there is a significant peak due to the Y(4260). A fit to the data in the range 3.74–5.50 GeV/c2 yields a mass value 4245±5(stat)±4(syst) MeV/c2 and a width value 11415+16(stat)±7(syst) MeV for this state. We do not confirm the report from the Belle Collaboration of a broad structure at 4.01 GeV/c2. In addition, we investigate the π+π system which results from Y(4260) decay.  [Show abstract] [Hide abstract]
ABSTRACT: A precise measurement of the cross section of the process e+e→π+π(γ) from threshold to an energy of 3 GeV is obtained with the initialstate radiation (ISR) method using 232 fb1 of data collected with the BABAR detector at e+e centerofmass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e+e→μ+μ(γ)γISR, which is found to agree with the nexttoleadingorder QED prediction to within 1.1%. The cross section for the process e+e→π+π(γ) is obtained with a systematic uncertainty of 0.5% in the dominant ρ resonance region. The leadingorder hadronic contribution to the muon magnetic anomaly calculated using the measured ππ cross section from threshold to 1.8 GeV is (514.1±2.2(stat)±3.1(syst))×1010.  [Show abstract] [Hide abstract]
ABSTRACT: In a sample of 471×106 BB̅ events collected with the BABAR detector at the PEPII e+e collider we study the rare decays B→K(*)ℓ+ℓ, where ℓ+ℓ is either e+e or μ+μ. We report results on partial branching fractions and isospin asymmetries in seven bins of dilepton masssquared. We further present CP and leptonflavor asymmetries for dilepton masses below and above the J/ψ resonance. We find no evidence for CP or leptonflavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.  [Show abstract] [Hide abstract]
ABSTRACT: We report measurements of partial branching fractions for inclusive charmless semileptonic B decays B̅ →Xuℓν̅ and the determination of the Cabibbo–Kobayashi–Maskawa (CKM) matrix element Vub. The analysis is based on a sample of 467×106 Υ(4S)→BB̅ decays recorded with the BABAR detector at the PEPII e+e storage rings. We select events in which the decay of one of the B mesons is fully reconstructed and an electron or a muon signals the semileptonic decay of the other B meson. We measure partial branching fractions ΔB in several restricted regions of phase space and determine the CKM element Vub based on different QCD predictions. For decays with a charged lepton momentum pℓ*>1.0 GeV in the B meson rest frame, we obtain ΔB=(1.80±0.13stat±0.15sys±0.02theo)×103 from a fit to the twodimensional MXq2 distribution. Here, MX refers to the invariant mass of the final state hadron X and q2 is the invariant mass squared of the charged lepton and neutrino. From this measurement we extract Vub=(4.33±0.24exp±0.15theo)×103 as the arithmetic average of four results obtained from four different QCD predictions of the partial rate. We separately determine partial branching fractions for B̅ 0 and B decays and derive a limit on the isospin breaking in B̅ →Xuℓν̅ decays.  [Show abstract] [Hide abstract]
ABSTRACT: We report the results of a study of the exclusive charmless semileptonic decays, B^0 > pi^ l^+ nu, B^+ > pi^0 l^+ nu, B^+ > omega l^+ nu, B^+ > eta l^+ nu and B^+ > eta^' l^+ nu, (l = e or mu) undertaken with approximately 462x10^6 B\bar{B} pairs collected at the Upsilon(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions in several bins of q^2, the square of the momentum transferred to the leptonneutrino pair, for B^0 > pi^ l^+ nu, B^+ > pi^0 l^+ nu, B^+ > omega l^+ nu and B^+ > eta l^+ nu. From these distributions, we extract the formfactor shapes f_+(q^2) and the total branching fractions BF(B^0 > pi^ l^+ nu) = (1.45 +/ 0.04_{stat} +/ 0.06_{syst})x10^4 (combined pi^ and pi^0 decay channels assuming isospin symmetry), BF(B^+ > omega l^+ nu) = (1.19 +/ 0.16_{stat} +/ 0.09_{syst})x10^4 and BF(B^+ > eta l^+ nu) = (0.38 +/ 0.05_{stat} +/ 0.05_{syst})x10^4. We also measure BF(B^+ > eta^' l^+ nu) = (0.24 +/ 0.08_{stat} +/ 0.03_{syst})x10^4. We obtain values for the magnitude of the CKM matrix element V_{ub} by direct comparison with three different QCD calculations in restricted q^2 ranges of B > pi l^+ nu decays. From a simultaneous fit to the experimental data over the full q^2 range and the FNAL/MILC lattice QCD predictions, we obtain V_{ub} = (3.25 +/ 0.31)x10^3, where the error is the combined experimental and theoretical uncertainty.  [Show abstract] [Hide abstract]
ABSTRACT: We study the processes e+e→K+Kπ+πγ, K+Kπ0π0γ, and K+KK+Kγ, where the photon is radiated from the initial state. About 84 000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb1 of BABAR data. The invariant mass of the hadronic final state defines the e+e centerofmass energy, so that the K+Kπ+πγ data can be compared with direct measurements of the e+e→K+Kπ+π reaction. No direct measurements exist for the e+e→K+Kπ0π0 or e+e→K+KK+K reactions, and we present an update of our previous result based on a data sample that is twice as large. Studying the structure of these events, we find contributions from a number of intermediate states and extract their cross sections. In particular, we perform a more detailed study of the e+e→ϕ(1020)ππγ reaction and confirm the presence of the Y(2175) resonance in the ϕ(1020)f0(980) and K+Kf0(980) modes. In the charmonium region, we observe the J/ψ in all three final states and in several intermediate states, as well as the ψ(2S) in some modes, and measure the corresponding products of branching fraction and electron width. 
Article: Search for the decay modes B±→h±τℓ
[Show abstract] [Hide abstract]
ABSTRACT: We present a search for the lepton flavor violating decay modes B±→h±τℓ (h=K, π; ℓ=e, μ) using the BABAR data sample, which corresponds to 472×106 BB̅ pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and ℓ candidates, we are able to fully determine the τ fourmomentum. The resulting τ candidate mass is our main discriminant against combinatorial background. We see no evidence for B±→h±τℓ decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 105.  [Show abstract] [Hide abstract]
ABSTRACT: We perform amplitude analyses of the decays B0→K+KKS0, B+→K+KK+, and B+→KS0KS0K+, and measure CPviolating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106 BB̅ decays, collected with the BABAR detector at the PEPII asymmetricenergy B factory at the SLAC National Accelerator Laboratory. For B+→K+KK+, we find a direct CP asymmetry in B+→ϕ(1020)K+ of ACP=(12.8±4.4±1.3)%, which differs from zero by 2.8σ. For B0→K+KKS0, we measure the CPviolating phase βeff(ϕ(1020)KS0)=(21±6±2)°. For B+→KS0KS0K+, we measure an overall direct CP asymmetry of ACP=(45+4±2)%. We also perform an angularmoment analysis of the three channels and determine that the fX(1500) state can be described well by the sum of the resonances f0(1500), f2′(1525), and f0(1710).
Publication Stats
7k  Citations  
2,509.60  Total Impact Points  
Top Journals
 Physical Review D (183)
 Physical Review Letters (172)
 Physical review D: Particles and fields (32)
 Physical Review Letters (26)
 Physical Review D (2)
Institutions

20062009

Université de Savoie
Chambéry, RhôneAlpes, France


20012005

RuhrUniversität Bochum
 Institut für Experimentalphysik I
Bochum, North RhineWestphalia, Germany
