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Gonzalez-Alonso, M., Pich, A., & Prades, J. (2010). Pinched weights and duality violation in QCD sum rules: A critical analysis. Phys. Rev. D, 82(1), 014019–7pp.
Abstract: We analyze the so-called pinched weights, that are generally thought to reduce the violation of quarkhadron duality in finite-energy sum rules. After showing how this is not true in general, we explain how to address this question for the left-right correlator and any particular pinched weight, taking advantage of our previous work [1], where the possible high-energy behavior of the left-right spectral function was studied. In particular, we show that the use of pinched weights allows to determine with high accuracy the dimension six and eight contributions in the operator-product expansion, O-6 = (-4.3(-0.7)(+0.9)) x 10(-3) GeV6 and O-8 = (-7.2(-5.3)(+4.2)) x 10(-3) GeV8.
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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Measurements of Charged Current Lepton Universality and vertical bar V-us vertical bar Using Tau Lepton Decays to e(-)(nu)over-bar(e)nu(tau), mu(-)(nu)over-bar(mu)nu(tau), pi(-)nu(tau), and K-nu(tau). Phys. Rev. Lett., 105(5), 051602–8pp.
Abstract: Using 467 fb(-1) of e(+)e(-) annihilation data collected with the BABAR detector, we measure B(tau(-)->mu(-)(nu) over bar (mu)nu(tau))/B(tau(-)-> e(-)(nu) over bar (e)nu(tau)) = (0.9796 +/- 0.0016 +/- 0.0036), B(tau(-)->pi(-)nu(tau))/B(tau(-)-> e(-)nu(e)nu(tau)) = (0.5945 +/- 0.0014 +/- 0.0061), and B(tau(-)-> K-nu(tau))/B(tau(-)-> e(-)nu(e)nu(tau)) = (0.03882 +/- 0.00032 +/- 0.00057), where the uncertainties are statistical and systematic, respectively. From these precision similar to measurements, we test the standard model assumption of μ- e and tau – μcharge current lepton universality and provide determinations of vertical bar V-us vertical bar experimentally independent of the decay of a kaon.
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BABAR Collaboration(del Amo Sanchez, P. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). B-meson decays to eta ' rho, eta ' f(0), and eta ' K*. Phys. Rev. D, 82(1), 011502–8pp.
Abstract: We present measurements of B-meson decays to the final states eta'rho, eta'f(0), and eta'K*, where K* stands for a vector, scalar, or tensor strange meson. We observe a significant signal or evidence for eta'rho(+) and all the eta'K* channels. We also measure, where applicable, the charge asymmetries, finding results consistent with no direct CP violation in all cases. The measurements are performed on a data sample consisting of 467 X 10(6) B (B) over bar pairs, collected with the BABAR detector at the PEP-II e(+)e(-) collider at the SLAC National Accelerator Laboratory. Our results favor the theoretical predictions from perturbative QCD and QCD factorization and we observe an enhancement of the tensor K-2*(1430) with respect to the vector K*(892) component.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Studying the underlying event in Drell-Yan and high transverse momentum jet production at the Tevatron. Phys. Rev. D, 82(3), 034001–21pp.
Abstract: We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles produced in association with a large transverse momentum jet (similar to 2: 2 fb(-1)) or with a Drell-Yan lepton pair (similar to 2.7 fb(-1)) in the Z-boson mass region [70 < M(pair) < 110 GeV/c(2)] as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton pair or the leading jet in each event to define regions of eta-phi space that are sensitive to the modeling of the underlying event. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte Carlo models.
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Rafi Alam, M., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2010). Weak kaon production off the nucleon. Phys. Rev. D, 82(3), 033001–8pp.
Abstract: The weak kaon production off the nucleon induced by neutrinos is studied at the low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. This process is also potentially important for the analysis of proton decay experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are f pi, the pion decay constant, Cabibbo's angle, the proton and neutron magnetic moments, and the axial vector coupling constants for the baryons octet, D and F, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. The studied mechanisms are the main source of kaon production for neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva and T2K.
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