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Bridges, M., Cranmer, K., Feroz, F., Hobson, M., Ruiz de Austri, R., & Trotta, R. (2011). A coverage study of the CMSSM based on ATLAS sensitivity using fast neural networks techniques. J. High Energy Phys., 03(3), 012–23pp.
Abstract: We assess the coverage properties of confidence and credible intervals on the CMSSM parameter space inferred from a Bayesian posterior and the profile likelihood based on an ATLAS sensitivity study. In order to make those calculations feasible, we introduce a new method based on neural networks to approximate the mapping between CMSSM parameters and weak-scale particle masses. Our method reduces the computational effort needed to sample the CMSSM parameter space by a factor of similar to 10(4) with respect to conventional techniques. We find that both the Bayesian posterior and the profile likelihood intervals can significantly over-cover and identify the origin of this effect to physical boundaries in the parameter space. Finally, we point out that the effects intrinsic to the statistical procedure are conflated with simplifications to the likelihood functions from the experiments themselves.
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Nieves, J., Ruiz Simo, I., & Vicente Vacas, M. J. (2011). Inclusive charged-current neutrino-nucleus reactions. Phys. Rev. C, 83(4), 045501–19pp.
Abstract: We present a model for weak charged-current induced nuclear reactions at energies of interest for current and future neutrino oscillation experiments. This model is a natural extension of the work in Refs. [1,2], where the quasielastic contribution to the inclusive electron and neutrino scattering on nuclei was analyzed. The model is based on a systematic many-body expansion of the gauge boson absorption modes that includes one, two, and even three-body mechanisms, as well as the excitation of Delta isobars. The whole scheme has no free parameters, besides those previously adjusted to the weak pion production off the nucleon cross sections in the deuteron, since all nuclear effects were set up in previous studies of photon, electron, and pion interactions with nuclei. We have discussed at length the recent charged-current quasielastic MiniBooNE cross section data, and showed that two-nucleon knockout mechanisms are essential to describing these measurements.
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Chang, Q., Li, X. Q., & Yang, Y. D. (2011). The effects of a family nonuniversal Z ' boson on B -> pi pi decays. Int. J. Mod. Phys. A, 26(7-8), 1273–1294.
Abstract: Motivated by the measured large branching ratio of (B) over bar (0) --> pi(0)pi(0) (the so-called pi pi puzzle), we investigate the effects of a family nonuniversal Z' model on the tree-dominated B --> pi pi decays. We find that the Z' coupling parameter zeta(LR)(d) similar to 0.05 with a nontrivial new weak phase phi(L)(d) similar to -50 degrees, which is relevant to the Z' contributions to the QCD penguin sector Delta C-5, is needed to reconcile the observed discrepancy. Combined with the recent fitting results from B --> pi K, pi K* and rho K decays, the Z' parameter spaces are severely reduced but still not excluded entirely, implying that both the “pi pi” and “pi K” puzzles could be accommodated simultaneously within such a family nonuniversal Z' model.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Analysis of the D+ -> K- pi(+) e(+) nu(e) decay channel. Phys. Rev. D, 83(7), 072001–35pp.
Abstract: Using 347: 5 fb(-1) of data recorded by the BABAR detector at the PEP-II electron-positron collider, 244 x 10(3) signal events for the D+ -> K- pi(+)e(+)nu(e) decay channel are analyzed. This decay mode is dominated by the (K) over bar*(892)(0) contribution. We determine the (K) over bar*(892)(0) parameters: m(K*(892)0) (895.4 +/- 0.2 +/- 0.2) MeV/c(2),Gamma(0)(K*(892)0) (46.5 +/- 0.3 +/- 0.2) MeV/c(2), and the Blatt-Weisskopf parameter r(BW) = 2.1 +/- 0.5 +/- 0.5 (GeV/c)(-1), where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at q(2) = 0 (r(V) = V(0)/A(1)(0) = 1.463 +/- 0.031, r(2) = A(2)(0)/A(1)(0) = 0.801 +/- 0.020 +/- 0.020) and the value of the axial-vector pole mass parametrizing the q(2) variation of A(1) and A(2): m(A) (2.63 +/- 0.10 +/- 0.13) GeV/c(2). The S-wave fraction is equal to (5.79 +/- 0.16 +/- 0: 15)%. Other signal components correspond to fractions below 1%. Using the D+ -> K-pi(+)pi(+) channel as a normalization, we measure the D+ semileptonic branching fraction: B(D+ K-pi(+)e(+)nu(e)) (4.00 +/- 0: 03 +/- 0.04 +/- 0.09) x 10(-2), where the third uncertainty comes from external inputs. We then obtain the value of the hadronic form factor A(1) at q(2) 0: A(1)(0) 0.6200 +/- 0.0056 +/- 0.0065 +/- 0.0071. Fixing the P-wave parameters, we measure the phase of the S wave for several values of the K pi mass. These results confirm those obtained with K pi production at small momentum transfer in fixed target experiments.
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Pierre Auger Collaboration(Abreu, P. et al), & Pastor, S. (2011). Search for first harmonic modulation in the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory. Astropart Phys., 34(8), 627–639.
Abstract: We present the results of searches for dipolar-type anisotropies in different energy ranges above 2.5 x 10(17) eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% C.L. for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2011). Search for Supersymmetry Using Final States with One Lepton, Jets, and Missing Transverse Momentum with the ATLAS Detector in sqrt(s)=7 TeV pp Collisions. Phys. Rev. Lett., 106(13), 131802–19pp.
Abstract: This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from root s = 7 TeV proton-proton collisions at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35 pb(-1). No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. Within this framework, for A(0) = 0 GeV, tan beta = 3, and μ> 0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidence level.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Measurement of b Hadron Lifetimes in Exclusive Decays Containing a J/Psi in p(p)over-bar Collisions at sqrt(s)=1.96 TeV. Phys. Rev. Lett., 106(12), 121804–8pp.
Abstract: We report on a measurement of b-hadron lifetimes in the fully reconstructed decay modes B+-> J/psi K+, B-0 -> J/psi K*(892)(0), B-0 -> J/psi K-s(0), and Lambda(0)(b)-> J/psi Lambda(0) using data corresponding to an integrated luminosity of 4.3 fb(-1), collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are tau(B+)=[1.639 +/- 0.009(stat)+/- 0.009(syst)]ps, tau(B-0)=[1.507 +/- 0.010(stat)+/- 0.008(syst)]ps, and tau(Lambda(0)(b))=[1.537 +/- 0.045(stat)+/- 0.014(syst)]ps. The lifetime ratios are tau(B+)/tau(B-0)=[1.088 +/- 0.009(stat)+/- 0.004(syst)] and tau(Lambda(0)(b))/tau(B-0)=[1.020 +/- 0.030(stat)+/- 0.008(syst)]. These are the most precise determinations of these quantities from a single experiment.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2011). Search for Diphoton Events with Large Missing Transverse Energy in 7 TeV Proton-Proton Collisions with the ATLAS Detector. Phys. Rev. Lett., 106(12), 121803–19pp.
Abstract: A search for diphoton events with large missing transverse energy is presented. The data were collected with the ATLAS detector in proton-proton collisions at root s = 7 TeV at the CERN Large Hadron Collider and correspond to an integrated luminosity of 3: 1 pb(-1). No excess of such events is observed above the standard model background prediction. In the context of a specific model with one universal extra dimension with compactification radius R and gravity-induced decays, values of 1/R < 729 GeV are excluded at 95% C. L., providing the most sensitive limit on this model to date.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of the B-0 -> pi(-)l(+)nu and B+ -> eta(l)l(+)nu branching fractions, the B-0 -> pi(-)l(+)nu and B+ -> eta l(+)nu form- factor shapes, and determination of |Vub|. Phys. Rev. D, 83(5), 052011–16pp.
Abstract: We report the results of a study of the exclusive charmless semileptonic decays, B+ -> eta(l)l(+)nu and B-0 -> pi(-)l(+)nu undertaken with approximately 464 x 10(6) B (B) over bar pairs collected at the Y(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 for B+ -> eta l(+)nu and B-0 -> pi(-)l(+)nu decays in three and 12 bins of q(2), respectively, from which we extract the f (+)(q(2)) form-factor shapes and the total branching fractions B(B+ -> eta l(+)nu)= (0.36 +/- 0.05(stat) +/- 0.04(syst)) x 10(-4) and B(B-0 -> pi(-)l(+)nu) = (1.42 +/- 0.05(stat) +/- 0.07(syst)) x 10(-4). We also measure B(B+ -> eta'l(+)nu) = (0.24 +/- 0.08(stat) +/- 0.03(syst)) x 10(-4). We obtain values for the magnitude of the CKM matrix element |V-ub| using three different QCD calculations.
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MiniBooNE Collaboration(Aguilar-Arevalo, A. A. et al), & Sorel, M. (2011). Measurement of nu(mu)-induced charged-current neutral pion production cross sections on mineral oil at E-nu is an element of 0.5-2.0 GeV. Phys. Rev. D, 83(5), 052009–17pp.
Abstract: Using a custom 3-Cerenkov ring fitter, we report cross sections for nu(mu)-induced charged-current single pi(0) production on mineral oil (CH2) from a sample of 5810 candidate events with 57% signal purity over an energy range of 0.5-2.0 GeV. This includes measurements of the absolute total cross section as a function of neutrino energy, and flux-averaged differential cross sections measured in terms of Q(2), mu(-) kinematics, and pi(0) kinematics. The sample yields a flux-averaged total cross section of (9.2 +/- 0.3(stat) +/- 1.5(syst)) X 10(-39) cm(2)/CH2 at mean neutrino energy of 0.965 GeV.
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