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HADES Collaboration(Agakishiev, G. et al), Diaz, J., & Gil, A. (2010). Lambda-p femtoscopy in collisions of Ar + KCl at 1.76AGeV. Phys. Rev. C, 82(2), 021901–5pp.
Abstract: Results on Lambda p femtoscopy are reported at the lowest energy so far. At a beam energy of 1.76AGeV, the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer ( HADES) at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of Lambda p correlations at low relative momenta. The experimental correlation function is compared to corresponding model calculations allowing the determination of the space-time extent of the Lambda p emission source. The Lambda p source radius is found to be slightly smaller than the pp correlation radius for a similar collision system. The present Lambda p radius is significantly smaller than that found for Au + Au/Pb + Pb collisions in the AGS, SPS, and RHIC energy domains but larger than that observed for electroproduction from He. Taking into account all available data, we find the Lambda p source radius to increase almost linearly with the number of participants to the power of one-third.
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Sun, B. X., Garzon, E. J., & Oset, E. (2010). Radiative decay into gamma-baryon of dynamically generated resonances from the vector-baryon interaction. Phys. Rev. D, 82(3), 034028–11pp.
Abstract: We study the radiative decay into gamma and a baryon of the SU(3) octet and decuplet of nine and ten resonances that are dynamically generated from the interaction of vector mesons with baryons of the octet and the decuplet, respectively. We obtain quite different partial decay widths for the various resonances, and for different charge states of the same resonance, suggesting that the experimental investigation of these radiative decays should bring much information on the nature of these resonances. For the case of baryons of the octet we determine the helicity amplitudes and compare them with experimental data when available.
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CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2010). Search for the Production of Scalar Bottom Quarks in p(p)over-bar Collisions at root s=1.96 TeV. Phys. Rev. Lett., 105(8), 081802–7pp.
Abstract: We report on a search for direct scalar bottom quark (sbottom) pair production in p (p) over bar collisions at root s = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65 fb(-1) of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c(2), sbottom masses up to 230 GeV/c(2) are excluded at 95% confidence level.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Measurement of D-0-(D)over-bar(0) Mixing Parameters Using D-0 -> K-S(0)pi(+) pi(-) and D-0 -> (KSK+K-)-K-0 Decays. Phys. Rev. Lett., 105(8), 081803–7pp.
Abstract: We report a direct measurement of D-0-(D) over bar (0) mixing parameters through a time-dependent amplitude analysis of the Dalitz plots of D-0 -> K-S(0)pi(+)pi(-) and, for the first time, D-0 -> (KSK+K-)-K-0 decays. The low-momentum pion pi(+)(s) in the decay D*(+) -> D-0 pi(+)(s) identifies the flavor of the neutral D meson at its production. Using 468.5 fb(-1) of e(+)e(-) colliding-beam data recorded near root s = 10.6 by the BABAR detector at the PEP-II asymmetric-energy collider at SLAC, we measure the mixing parameters x = [1.6 + 2.3(stat) +/- 1.2(syst) +/- 0.8(model)] X 10(-3), and y = [5.7 +/- 2.0(stat) +/- 1.3(syst) +/- 0.7(model)] X 10(-3). These results provide the best measurement to date of x and y. The knowledge of the value of x, in particular, is crucial for understanding the origin of mixing.
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ATLAS Collaboration(Abat, E. et al), Castillo Gimenez, V., Ferrer, A., Gonzalez, V., Higon-Rodriguez, E., Mitsou, V. A., et al. (2010). Study of energy response and resolution of the ATLAS barrel calorimeter to hadrons of energies from 20 to 350 GeV. Nucl. Instrum. Methods Phys. Res. A, 621(1-3), 134–150.
Abstract: A fully instrumented slice of the ATLAS detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the results of the measurements of the response of the barrel calorimeter to hadrons with energies in the range 20-350 GeV and beam impact points and angles corresponding to pseudo-rapidity values in the range 0.2-0.65 are reported. The results are compared to the predictions of a simulation program using the Geant 4 toolkit.
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AGATA Collaboration, Farnea, E., Recchia, F., Bazzacco, D., Kroll, T., Podolyak, Z., et al. (2010). Conceptual design and Monte Carlo simulations of the AGATA array. Nucl. Instrum. Methods Phys. Res. A, 621(1-3), 331–343.
Abstract: The aim of the Advanced GAmma Tracking Array (AGATA) project is the construction of an array based on the novel concepts of pulse shape analysis and gamma-ray tracking with highly segmented Ge semiconductor detectors. The conceptual design of AGATA and its performance evaluation under different experimental conditions has required the development of a suitable Monte Carlo code. In this article, the description of the code as well as simulation results relevant for AGATA, are presented.
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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 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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Martinez Torres, A., & Oset, E. (2010). Novel Interpretation of the “Theta(+)(1540) Pentaquark” Peak. Phys. Rev. Lett., 105(9), 092001–4pp.
Abstract: We use a theoretical model of the gamma d --> K+K- np reaction adapted to the experiment done at LEPS where a peak was observed and associated with the Theta(+)(1540) pentaquark. The study shows that the method used in the experiment to assign momenta to the undetected proton and neutron, together with the chosen cuts, necessarily creates an artificial broad peak in the assumed K(+)n invariant mass in the region of the claimed Theta(+)(1540), such that the remaining strength seen for the experimental peak is compatible with a fluctuation of 2 sigma significance.
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Xie, J. J., & Wilkin, C. (2010). Associated strangeness production in the pp -> pK(+) K(-)p and pp -> pK(+)pi(0)Sigma(0) reactions. Phys. Rev. C, 82(2), 025210–6pp.
Abstract: The total and differential cross sections for associated strangeness production in the pp -> pK(+) K(-)p and pp -> pK(+)pi(0)Sigma(0) reactions have been studied in a unified approach using an effective Lagrangian model. It is assumed that both the K(-)p and pi(0)Sigma(0) final states originate from the decay of the Lambda(1405) that was formed in the production chain pp -> p(N*(1535). K+ Lambda(1405)). The available experimental data are well reproduced, especially the ratio of the two total cross sections, which is much less sensitive to the particular model of the entrance channel. The significant coupling of the N*(1535) to Lambda(1405)K is further evidence for large ss components in the quark wave function of the N*(1535).
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