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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of the decay (B)over-bar(0) -> Lambda(+)(c)(p)over-bar pi(0). Phys. Rev. D, 82(3), 031102–8pp.
Abstract: In a sample of 467 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP- II collider at SLAC we have observed the decay (B) over bar (0) -> Lambda(+)(c)(p) over bar pi(0) and measured the branching fraction to be (1.94 +/- 0.17 +/- 0.14 +/- 0.50 x 10(-4), where the uncertainties are statistical, systematic, and the uncertainty on the Lambda(+)(c) -> pK(-)pi(+) branching fraction, respectively. We determine an upper limit of 1.5 x 10(-6) at 90% C.L. for the product branching fraction B((B) over bar (0) -> Sigma(+)(c) (2455)(p) over bar) x B(Lambda(+)(c) -> pK(-) pi(+)). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon- antibaryon pair.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of the top quark mass in the dilepton channel using m(T2) at CDF. Phys. Rev. D, 81(3), 031102–9pp.
Abstract: We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurement of Z gamma production in p(p)over-bar collisions at root s=1.96 TeV. Phys. Rev. D, 82(3), 031103–8pp.
Abstract: The production rate and kinematics of photons produced in association with Z bosons are studied using 2 fb(-1) of p (p) over bar collision data collected at the Collider Detector at Fermilab. The cross section for p (p) over bar -> l(+)l(-)gamma + X ( where the leptons l are either muons or electrons with dilepton mass M-ll > 40 GeV/c(2), and where the photon has transverse energy E-T(gamma) > 7 GeV and is well separated from the leptons) is 4.6 +/- 0.2(stat) +/- 0.3 (syst) +/- 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon E-T distribution from Z gamma events where the Z has decayed to mu(+) mu(-) ,e(+) e(-), or nu(+) nu(-) to set limits on anomalous (non standard model) trilinear couplings between photons and Z bosons.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Measurements of branching fraction ratios and CP asymmetries in B-+/- -> DCPK +/- decays in hadron collisions. Phys. Rev. D, 81(3), 031105–9pp.
Abstract: We reconstruct B-+/- -> DK +/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb(-1) of integrated luminosity. We select decay modes where the D meson decays to either K-pi(+) (flavor eigenstate) or K-K+, pi(-)pi(+) (CP-even eigenstates), and measure the direct CP asymmetry A(CP+) = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle gamma. They are performed here for the first time using data from hadron collisions.
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Caballero, L., Rubio, B., Kleinheinz, P., Yates, S. W., Algora, A., Dewald, A., et al. (2010). Two-phonon octupole excitation in Gd-146. Phys. Rev. C, 81(3), 031301–4pp.
Abstract: Based on experimental evidence from the Sm-144(alpha,2n) reaction, the 3484.7- keV 6(+) state in Gd-146 is identified as the highest-spin member of the 3(-) circle times 3(-) two-phonon octupole quartet. A previously unknown gamma line of 1905.8 keV and E3 character feeding the 3(-) octupole state has been observed. These results represent the first observation of a 6(+) -> 3(-) -> 0(+) cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6(+) state as a two-phonon octupole excitation.
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