Browsing by Author "Garra Tico, J."
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item 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, XinchouWe 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.Item 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.Item Search for a Low-Mass Scalar Higgs Boson Decaying to a Tau Pair in Single-Photon Decays of ϒ(1s)(American Physical Society, 2013-10-10) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; BaBar Collaboration; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.We search for a low-mass scalar CP-odd Higgs boson, A⁰, produced in the radiative decay of the upsilon resonance and decaying into a τ⁺τ⁻ pair: ϒ(1S)→γA⁰. The production of ϒ(1S) mesons is tagged by ϒ(2S) π⁺π⁻ ϒ(1S) transitions, using a sample of (98.3 ± 0.9) x 10⁶ ϒ(2S) mesons collected by the BABAR detector. We find no evidence for a Higgs boson in the mass range 3.5 ≤ m_{A⁰} ≤ 9.2 GeV, and combine these results with our previous search for the tau decays of the light Higgs in radiative ϒ(3S) decays, setting limits on the coupling of A⁰ to the bb̅ quarks in the range 0.09-1.9. Our measurements improve the constraints on the parameters of the next-to-minimal-supersymmetric Standard Model and similar theories with low-mass scalar degrees of freedom.Item Study of the Reaction e⁺e⁻ → ψ(2S)π⁺π⁻ via Initial-State Radiation at BaBar(American Physical Society, 2014-06-25) Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A.; Eigen, G.; Izen, Joseph M.; Lou, Xinchou; 250674117 (Izen, JM); 250674117 (Izen, JM); Lou, Xinchou; Izen, Joseph M.We study the process e⁺e⁻ → ψ(2S)π⁺ π⁻ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BABAR detector at center-of-mass energies at and near the Υ(nS) (n=2, 3, 4) resonances and correspond to an integrated luminosity of 520 fb⁻¹. We investigate the ψ(2S)π⁺ π⁻ mass distribution from 3.95 to 5.95 GeV/c², and measure the center-of-mass energy dependence of the associated e⁺e⁻→ ψ(2S)π⁺ π⁻ cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the ψ(2S)π⁺ π⁻ mass distribution corresponding to the decay mode ψ(2S)→J/ψπ⁺ π⁻ yields a mass value of 4340 ±16 (stat) ± 9 (syst) MeV/c² and a width of 94 ± 32 (stat) ±13 (syst) MeV for the first resonance, and for the second a mass value of 4669 ± 21(stat) ± 3 (syst) MeV/c² and a width of 104 ± 48 (stat) ±10 (syst) MeV. In addition, we show the π⁺ π⁻ mass distributions for these resonant regions.