Browsing by Author "Grauges, E."

Now showing 1 - 20 of 49

Antideuteron Production in ϒ(nS) Decays and in e⁺e⁻→qq̅ at √s ≈ 10.58 GeV
(American Physical Society, 2014-06-24) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present measurements of the inclusive production of antideuterons in e+e- annihilation into hadrons at ≈ 10.58 GeV center-of-mass energy and in ϒ(1S,2S,3S) decays. The results are obtained using data collected by the BABAR detector at the PEP-II electron-positron collider. Assuming a fireball spectral shape for the emitted antideuteron momentum, we find ℬ(ϒ(1S) → d̅X) = (2. 81 ± 0.49 (stat) _{-0.24}^{+0.20} (syst)) x 10⁻⁵ ℬ(ϒ(2S) → d̅X) = (2. 64 ± 0.11 (stat) _{-0.21}^{+0.26} (syst)) x 10⁻⁵, B(ϒ(3S) → d̅X) = (2. 33 ± 0.15 (stat) _{-0.28}^{+0.31} (syst)) x 10⁻⁵, and σ(e⁺e⁻ → d̅X) = (9.63 ± 0.41 (stat) _{-1.01}^{+1.17} (syst) fb.
Bottomonium Spectroscopy and Radiative Transitions Involving the χ_{bJ} (1p, 2p) States at BaBar
(American Physical Society, 2014-12-24) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We use (121 ± 1) million ϒ(3S) and (98 ± 1) million ϒ(2S) mesons recorded by the BABAR detector at the PEP-II e⁺e⁻ collider at SLAC to perform a study of radiative transitions involving the χ_{bJ}(1P, 2P) states in exclusive decays with μ⁺μ⁻γγ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the χ_{b0}(2P) → γϒ(2S) and χ_{b0}(1P) → γϒ(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e⁺e⁻ pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring ϒ(3S) → γχ_{b1,2}(1P) decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for χ_b transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian.
Collins Asymmetries in Inclusive Charged KK and Kπ Pairs Produced in e⁺e⁻ Annihilation
(American Physical Society, 2015-12-22) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present measurements of Collins asymmetries in the inclusive process e⁺e⁻ → h₁h₂Χ, h₁h₂ = KK, Kπ, ππ at the center-of-mass energy of 10.6 GeV, using a data sample of 468 fb⁻¹ collected by the BABAR experiment at the PEP-II B factory at SLAC National Accelerator Center. Considering hadrons in opposite thrust hemispheres of hadronic events, we observe clear azimuthal asymmetries in the ratio of unlike sign to like sign, and unlike sign to all charged h₁h₂ pairs, which increase with hadron energies. The Kπ asymmetries are similar to those measured for the ππ pairs, whereas those measured for high-energy KK pairs are, in general, larger.
Cross sections for the reactions e⁺e⁻→ K_s^0 K_L^0, K_s^0 K_L^0 π⁺π⁻, K_s^0 K_s^0 π⁺π⁻, K_s^0 K_s^0 K⁺ K⁻ from events with initial-state radiation
(American Physical Society, 2014-05-06) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; 56366505900 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We study the processes e⁺e⁻ → K_s^0 K_L^0γ, K_s^0 K_L^0π⁺π⁻γ, K_s^0 K_s^0 π⁺ π⁻ γ, K_s^0 K_s^0 K⁺ K⁻ γ, where the photon is radiated from the initial state. providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb−1 of data collected with the BABAR detector at SLAC. We observe the ϕ(1020) resonance in the K_s^0 K_L^0 final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the e⁺e⁻ → K_s^0 K_L^0 cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the e⁺e⁻ → K_s^0 K_L^0 π⁺π⁻ and K_s^0 K_s^0 K⁺ K⁻ cross sections and study the intermediate resonance structures. We obtain the first observations of J/ψ decay to the K_s^0 K_L^0 π⁺π⁻, K_s^0 K_s^0 π⁺π⁻, and K_s^0 K_s^0 K⁺ K⁻ final states.
Cyclopamine Tartrate, An Inhibitor of Hedgehog Signaling, Strongly Interferes with Mitochondrial Function and Suppresses Aerobic Respiration in Lung Cancer Cells
(American Physical Society, 2016-03-29) del Amo Sanchez. P.; Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); Izen, Joseph M.; Lou, Xinchou
We measure the time-dependent CP asymmetry in the radiative-penguin decay B0→KS0π-π+γ, using a sample of 471×106 (4S)→BB-events recorded with the BABAR detector at the PEP-II e+e- storage ring at SLAC. Using events with mKππ<1.8 GeV/c2, we measure the branching fractions of B+→K+π-π+γ and B0→K0π-π+γ, the branching fractions of the kaonic resonances decaying to K+π-π+, as well as the overall branching fractions of the B+→ρ0K+γ, B+→K∗0π+γ and S-wave B+→(Kπ)0∗0π+γ components. For events from the ρ mass band, we measure the CP-violating parameters SKS0π+π-γ=0.14±0.25±0.03 and CKS0π+π-γ=-0.39±0.20-0.02+0.03, where the first uncertainties are statistical and the second are systematic. We extract from this measurement the time-dependent CP asymmetry related to the CP eigenstate ρ0KS0 and obtain SKS0ργ=-0.18±0.32-0.05+0.06, which provides information on the photon polarization in the underlying b→sγ transition.
Dalitz Plot Analyses of B⁰ → D⁻D⁰K⁺ and B⁺ → D̅⁰D⁰K⁺ Decays
(American Physical Society, 2015-03-02) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 56366505900 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present Dalitz plot analyses for the decays of B mesons to D⁻D⁰K⁺ and D̅⁰D⁰K⁺. We report the observation of the D*{s1} (2700)⁺ resonance in these two channels and obtain measurements of the mass M(D*{s1} (2700)⁺) = 2699{₋₇}⁺¹⁴ MeV/c² and of the width Γ(D*{s1} (2700)⁺) = 127{₋₁₉}⁺²⁴ MeV, including statistical and systematic uncertainties. In addition, we observe an enhancement in the D⁰K⁺ invariant mass around 2350-2500 MeV/c² in both decays B⁰ → D⁻D⁰K⁺ and B⁺ → D̅⁰D⁰K⁺, which we are not able to interpret. The results are based on 429 fb⁻¹ of data containing 471 x10⁶ BB̅ pairs collected at the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory.
Dalitz Plot Analysis of η_c → K⁺K⁻η and η_c → K⁺K⁻π⁰ in Two-Photon Interactions
(American Physical Society, 2014-06-16) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; 56366505900 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We study the processes γγ→K⁺K⁻η and γγ→K⁺K⁻π⁰ using a data sample of 519 fb⁻¹ recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e⁺e⁻ collider at center-of-mass energies at and near the Υ(nS) (n = 2, 3, 4) resonances. We observe η_c → K⁺K⁻π⁰ and η_c → K⁺K⁻η decays, measure their relative branching fraction, and perform a Dalitz plot analysis for each decay. We observe the K₀*(1430) → K η decay and measure its branching fraction relative to the K π decay mode to be R(K₀*(1430)) = ℬ(K₀*(1430) → K η) / ℬ(K₀*(1430) → K π) = 0.092 ± 0.025_(-0.025)^(+0.010). The η_c → K⁺K⁻η and K₀*(1430) → Kη results correspond to the first observations of these channels. The data also show evidence for η_c(2S) → K⁺K⁻π⁰ and first evidence for η_c(2S) → K⁺K⁻η.
Evidence for CP Violation in B⁺ → K*(892)⁺π⁰ from a Dalitz Plot Analysis of B⁺ → K_s⁰π⁺π⁰ Decays
(American Physical Society, 2017-10-02) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); Izen, Joseph M.; Lou, Xinchou
We report a Dalitz plot analysis of charmless hadronic decays of charged B mesons to the final state K_s⁰ π⁺π⁰ using the full BABAR data set of 470.9 ± 2.8 million BB̅ events collected at the Υ(4S) resonance. We measure the overall branching fraction and CP asymmetry to be Β(B⁺ → K⁰ π⁺π⁰) = (31.8 ± 1.8 ± 2.1_{-0.0}^{+6.0}) x 10⁻⁶ and A_{CP}(B⁺ → K⁰ π⁺π⁰) = 0.07 ± 0.05 ± 0.03_{-0.03}^{+0.02}, where the uncertainties are statistical, systematic, and due to the signal model, respectively. This is the first measurement of the branching fraction for B⁺ → K⁰ π⁺π⁰. We find first evidence of a CP asymmetry in B⁺ → K*(892)⁺π⁰ decays: A_{CP}(B⁺ → K*(892)⁺π⁰) = -0.52 ± 0.14 ± 0.04_{-0.02}^{+0.04}. The significance of this asymmetry, including systematic and model uncertainties, is 3.4 standard deviations. We also measure the branching fractions and CP asymmetries for three other intermediate decay modes.
Evidence for the Baryonic Decay B̅→ D⁰ΛΛ̅
(2014-06-06) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
Evidence is presented for the baryonic B meson decay B̅⁰ → D⁰ΛΛ̅ based on a data sample of 471 x 10⁶ BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric e⁺e⁻ collider located at the SLAC National Accelerator Laboratory. The branching fraction is determined to beℬ(B̅⁰ → D⁰ΛΛ̅) = (9.8_{-2.6}^{+2.9} ± 1.9) x 10⁻⁶, corresponding to a significance of 3.4 standard deviations including additive systematic uncertainties. A search for the related baryonic B meson decay B̅⁰ → D⁰Σ⁰Λ̅ with Σ⁰ → Λγ is performed and an upper limit ℬ(B̅⁰ → D⁰Σ⁰Λ̅ + B̅⁰ → D⁰ΛΣ̅⁰ < 3.1 x 10⁻⁵ is determined at 90% confidence level.
Evidence for the Decay B⁰ → ωω and Search for B⁰ → ωφ
(American Physical Society, 2014-03-05) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We describe searches for B meson decays to the charmless vector-vector final states ωω and ωφ with 471 x 10⁶ BB̅ pairs produced in e⁺e⁻ annihilation at √s̅ = 10.58 GeV using the BABAR detector at the PEP-II collider at the SLAC National Accelerator Laboratory. We measure the branching fraction ℬ(B⁰ → ωω) = (1.2 ± 0.3_{-0.2}^{+0.3}) 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 → ωφ) < 0.7 x 10⁻⁶ at 90% confidence level. These measurements provide the first evidence for the decay B⁰ → ωω, and an improvement of the upper limit for the decay B⁰ → ωφ.
Exclusive Measurements of b → sγ Transition Rate and Photon Energy Spectrum
(American Physical Society, 2012-10-17) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Izen, Joseph M.; Lou, Xinchou
We use 429 fb⁻¹ 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 → Χ_sγ) = (3.29 ± 0.19 ± 0.48) x 10⁻⁴ 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 best-fit values for the heavy-quark parameters, m_b and μ_π², in the kinetic and shape function models.
Improved Limits on B⁰ Decays to Invisible (+γ) Final States
(American Physical Society, 2012-09-27) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Izen, Joseph M.; Lou, Xinchou
We establish improved upper limits on branching fractions for B⁰ decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 x 10⁶ BB̅ pairs collected at the Υ(4S) resonance by the BABAR experiment at the PEP-II e⁺e⁻ storage ring at the SLAC National Accelerator Laboratory, we establish upper limits at the 90% onfidence level of 2.4 x 10⁻⁵ for the branching fraction of B⁰ → invisible and1.7 x 10⁻⁵ for the branching fraction of B⁰ → invisible + γ.
Measurement of Collins Asymmetries in Inclusive Production of Charged Pion Pairs in e⁺e⁻ Annihilation at BaBar
(American Physical Society, 2014-09-09) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present measurements of Collins asymmetries in the inclusive process e⁺e⁻ → ππX, where π stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb⁻¹ collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis.
Measurement of CP-Violating Asymmetries in B⁰ → (ρπ)⁰ Decays Using a Time-Dependent Dalitz Plot Analysis
(American Physical Society, 2013-07-19) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Brown, D. N.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present results for a time-dependent Dalitz plot measurement of CP-violating asymmetries in the mode B⁰ → π⁺π⁻π⁰. The data set is derived from the complete sample of 471 x 10⁶ BB̅ meson pairs collected with the BABAR detector at the PEP-II asymmetric-energy e⁺e⁻ collider at the SLAC National Accelerator Laboratory operating on the Υ(4S) resonance. We extract parameters describing the time-dependent B⁰ → ρπθ decay probabilities and CPθ asymmetries, including C=0.016 ± 0.059 ± 0.036, ΔC=0.234 ± 0.061 ± 0.048, S=0.053 ± 0.081 ± 0.034, and ΔS=0.054 ± 0.082 ± 0.039, where the uncertainties are statistical and systematic, respectively. We perform a two-dimensional likelihood scan of the direct CP-violation asymmetry parameters for B⁰ → ρ^± π^∓ decays, finding the change in χ² between the minimum and the origin (corresponding to no direct CPθ violation) to be Δχ² = 6.42. We present information on the CP-violating parameter αθ in a likelihood scan that incorporates B^± → ρπθ measurements. To aid in the interpretation of our results, statistical robustness studies are performed to assess the reliability with which the true values of the physics parameters can be extracted. Significantly, these studies indicate that αθ cannot be reliably extracted with our current sample size, though the other physics parameters are robustly extracted.
Measurement of D⁰-D̅⁰ Mixing and CP Violation in Two-Body D⁰ Decays
(American Physical Society, 2013-01-03) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M .; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We present a measurement of D⁰-D̅⁰ mixing and CP violation using the ratio of lifetimes simultaneously extracted from a sample of D⁰ mesons produced through the flavor-tagged process D*⁺ → D⁰π⁺, where D⁰ decays to K^∓ π^±, K⁻ K⁺, or π⁻ π⁺, along with the untagged decays D⁰ → K^∓ π^± and D⁰ → K⁻K⁺. The lifetimes of the CP-even, Cabibbo-suppressed modes K⁻K⁺ and π⁻ π⁺ are compared to that of the CP-mixed mode K^∓ π^± in order to measure y_{CP} and ΔY. We obtain y_{CP}=[0.72 ± 0.18(stat) ± 0.12(syst)]% and ΔY=[0.09 ± 0.26(stat) ±0.06(syst)]%, where ΔY constrains possible CP violation. The y_{CP} result excludes the null mixing hypothesis at 3.3σ significance. This analysis is based on an integrated luminosity of 468 fb⁻¹ collected with the BABAR detector at the PEP-II asymmetric-energy e⁺e⁻ collider.
Measurement of Initial-State-Final-State Radiation Interference in the Processes e⁺e⁻ → μ⁺μ⁻γ and e⁺e⁻ → π⁺π⁻γ
(2015-10-28) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 56366505900 (Lou, X); 250674117 (Izen, JM); Lou, Xinchou
Charge asymmetry in the processes e⁺e⁻ → μ⁺μ⁻γ and e⁺e⁻ → π⁺π⁻γ is measured using 232 fb⁻¹ of data collected with the BABAR detector at e⁺e⁻ center-of-mass energies near 10.58 GeV. An observable is introduced and shown to be very robust against detector asymmetries while keeping a large sensitivity to the physical charge asymmetry that results from the interference between initial-and final-state radiation (FSR). The asymmetry is determined as a function of the invariant mass of the final-state tracks from production threshold to a few GeV/c². It is compared to the expectation from QED for e⁺e⁻ → μ⁺μ⁻γ, and from theoretical models for e⁺e⁻ → π⁺π⁻γ. A clear interference pattern is observed in e⁺e⁻ → π⁺π⁻γ, particularly in the vicinity of the f₂(1270) resonance. The inferred rate of lowest-order FSR production is consistent with the QED expectation for e⁺e⁻ → μ⁺μ⁻γ, and is negligibly small for e⁺e⁻ → π⁺π⁻γ.
Measurement of the B → X₋s ℓ⁺ℓ⁻ Branching Fraction and Search for Direct CP Violation from a Sum of Exclusive Final States
(American Physical Society, 2014-05-30) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We measure the total branching fraction of the flavor-changing neutral-current process B→X_s ℓ⁺ℓ⁻, along with partial branching fractions in bins of dilepton and hadronic system (X_s) mass, using a sample of 471 x 10⁶ ϒ(4S) → BB̅ events recorded with the BABAR detector. The admixture of charged and neutral B mesons produced at PEP-II2 are reconstructed by combining a dilepton pair with 10 different X_s final states. Extrapolating from a sum over these exclusive modes, we measure a lepton-flavor-averaged inclusive branching fraction ℬ(B→X_s ℓ⁺ℓ⁻) = [6.73_{-0.64}^{+0.70}(stat)_{-0.25}^{+0.34}(exp syst) ± 0.50(model syst)] x 10⁻⁶ for m_{ℓ⁺ℓ⁻}^2 > 0.1 GeV²/c⁴. Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry A_{CP} in bins of dilepton mass; over the full dilepton mass range, we find A_{CP} = 0.04 ± 0.11 ± 0.01 for a lepton-flavor-averaged sample.
Measurement of the B+ → ω ℓ⁺ ν Branching Fraction with Semileptonically Tagged B Mesons
(American Physical Society, 2013-10-15) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We report a measurement of the branching fraction of the exclusive charmless semileptonic decay B⁺ → ωℓ⁺ ν where ℓ is either an electron or a muon. We use samples of B⁺ mesons tagged by a reconstructed charmed semileptonic decay of the other B meson in the event. The measurement is based on a data set of 426.1 fb⁻¹ of e⁺e⁻ collisions at a center-of-mass energy of 10.58 GeV recorded with the BABAR detector at the PEP-II asymmetric-energy e⁺e⁻ storage rings. We measure a branching fraction of ℬ(B⁺ → ωℓ⁺ ν)=(1.35 ± 0.21 ± 0.11) x 10⁻⁴, where the uncertainties are statistical and systematic, respectively. We also present measurements of the partial branching fractions in three bins of q², the invariant-mass squared of the lepton-neutrino system, and we compare them to theoretical predictions of the form factors.
Measurement of the D*(2010)⁺ Natural Linewidth and the D*(2010)⁺—D⁰ Mass Difference
(American Physical Society, 2013-09-09) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Stugu, B.; Lou, Xinchou; Izen, Joseph M.; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.
We measure the mass difference, Δm₀, between the D *(2010)⁺ and the D⁰ and the natural linewidth, Γ, of the transition D*(2010)⁺ → D⁰π⁺. The data were recorded with the BABAR detector at center-of-mass energies at and near the ϒ(4S) resonance, and correspond to an integrated luminosity of approximately 477 fb⁻¹. The D⁰ is reconstructed in the decay modes D⁰ → K⁻ π⁺ and D⁰ → K⁻ π⁺ π⁻ π⁺. For the decay mode D⁰ → K⁻ π⁺ we obtain Γ = (83.4 ± 1.7 ± 1.5) keV and Δm₀ = (145425.6 ± 0.6 ± 1.8) keV, where the quoted errors are statistical and systematic, respectively. For the D⁰ → K⁻ π⁺ π⁻ π⁺ mode we obtain Γ = (83.2 ± 1.5 ± 2.6) keV and Δm₀ = (145426.6 ± 0.5 ± 2.0) keV. The combined measurements yield Γ = (83.3 ± 1.2 ± 1.4) keV and Δm₀ = (145425.9 ± 0.4 ± 1.7) keV; the width is a factor of approximately 12 times more precise than the previous value, while the mass difference is a factor of approximately 6 times more precise.
Measurement of the D*(2010)⁺ –D⁺ Mass Difference
(American Physical Society, 2018-08-24) Lees, J. P.; Poireau, V.; Tisserand, V.; Grauges, E.; Palano, A.; Eigen, G.; Brown, D. N.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 0000-0003-0867-2189 (Lou, X); 250674117 (Izen, JM); Izen, Joseph M.; Lou, Xinchou
We measure the mass difference, Δm₊, between the D*(2010)⁺ and the D⁺ using the decay chain D*(2010)⁺ → D⁺π⁰ with D⁺ → K⁻π⁺π⁺. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(4S) resonance, and correspond to an integrated luminosity of approximately 468 fb⁻¹. We measure Δm₊ = (140 601.0 ± 6.8 [stat] ± 12.9 [syst]) keV. We combine this result with a previous BABAR measurement of Δm₀ ≡ m(D*(2010)⁺) - m(D⁰) to obtain Δm_D = m(D⁺) - m(D⁰) = (4824.9 ± 6.8 [stat] ± 12.9 [syst]) keV. These results are compatible with and approximately five times more precise than the Particle Data Group averages.