181 research outputs found

    Strangeness production time and the K+/pi+ horn

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    We construct a hadronic kinetic model which describes production of strange particles in ultrarelativistic nuclear collisions in the energy domain of SPS. We test this model on description of the sharp peak in the excitation function of multiplicity ratio K+/pi+ and demonstrate that hadronic model reproduces these data rather well. The model thus must be tested on other types of data in order to verify the hypothesis that deconfinement sets in at lowest SPS energies.Comment: proceedings of Hot Quarks 0

    Probing hadronic formation times with antiprotons in p+A reactions at AGS energies

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    The production of antiprotons in p+Ap+A reactions is calculated in a microscopic transport approach employing hadronic and string degrees of freedom (HSD). It is found that the abundancies of antiprotons as observed by the E910 Collaboration in p+Ap+A reactions at 12.3 GeV/c as well as 17.5 GeV/c can approximately be described on the basis of primary proton-nucleon and secondary meson-baryon production channels for all targets. The transport calculations demonstrate that the antiproton rapidity distributions for heavy targets are sensitive to the pˉ\bar{p} (or hadron) formation time in the nuclear medium. Within our analysis the data from the E910 Collaboration are reasonably described with a formation time of 0.40.8 0.4-0.8 fm/c in the hadron rest frame.Comment: 18 pages, LaTeX, 8 postscript figures; submitted to Nucl. Phys.

    Analysis of particle production in ultra-relativistic heavy ion collisions within a two-source statistical model

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    The experimental data on hadron yields and ratios in central lead-lead and gold-gold collisions at 158 AGeV/cc (SPS) and s=130\sqrt{s} = 130 AGeV (RHIC), respectively, are analysed within a two-source statistical model of an ideal hadron gas. A comparison with the standard thermal model is given. The two sources, which can reach the chemical and thermal equilibrium separately and may have different temperatures, particle and strangeness densities, and other thermodynamic characteristics, represent the expanding system of colliding heavy ions, where the hot central fireball is embedded in a larger but cooler fireball. The volume of the central source increases with rising bombarding energy. Results of the two-source model fit to RHIC experimental data at midrapidity coincide with the results of the one-source thermal model fit, indicating the formation of an extended fireball, which is three times larger than the corresponding core at SPS.Comment: 6 pages, REVTEX

    Parton-Hadron-String Dynamics: an off-shell transport approach for relativistic energies

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    The dynamics of partons, hadrons and strings in relativistic nucleus-nucleus collisions is analyzed within the novel Parton-Hadron-String Dynamics (PHSD) transport approach, which is applied to Pb+Pb collisions from 20 to 160 A GeV in order to explore the space-time regions of 'partonic matter'. We find that even central collisions at the top-SPS energy of 158 A GeV show a large fraction of non-partonic, i.e. hadronic or string-like matter, which can be viewed as a hadronic corona. Furthermore, we observe that the partonic phase has a very low impact on rapidity distributions of hadrons but a sizeable influence on the transverse mass distribution of final kaons due to the repulsive partonic mean fields. We also find a significant effect on the production of multi-strange antibaryons due to a slightly enhanced ssˉs{\bar s} pair production in the partonic phase from massive time-like gluon decay and a larger formation of antibaryons in the hadronization process. All differential hadron spectra are analyzed in comparison to the data of experimental collaborations.Comment: 33 pages, 23 figures, submitted to Nulc. Phys.

    Important pharmacogenetic information for drugs prescribed during the SARS-CoV-2 infection (COVID-19)

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    In December 2019, the severe acute respiratory syndrome virus-2 pandemic began, causing the coronavirus disease 2019. A vast variety of drugs is being used off-label as potential therapies. Many of the repurposed drugs have clinical pharmacogenetic guidelines available with therapeutic recommendations when prescribed as indicated on the drug label. The aim of this review is to provide a comprehensive summary of pharmacogenetic biomarkers available for these drugs, which may help to prescribe them more safelyM.N.-G. is co-financed by the European Social Fund and the Youth European Initiative; grant number PEJ-2018-TL/BMD-1108

    Observing many body effects on lepton pair production from low mass enhancement and flow at RHIC and LHC energies

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    The ρ\rho spectral function at finite temperature calculated using the real-time formalism of thermal field theory is used to evaluate the low mass dilepton spectra. The analytic structure of the ρ\rho propagator is studied and contributions to the dilepton yield in the region below the bare ρ\rho peak from the different cuts in the spectral function are discussed. The space-time integrated yield shows significant enhancement in the region below the bare ρ\rho peak in the invariant mass spectra. It is argued that the variation of the inverse slope of the transverse mass (MTM_T) distribution can be used as an efficient tool to predict the presence of two different phases of the matter during the evolution of the system. Sensitivity of the effective temperature obtained from the slopes of the MTM_T spectra to the medium effects are studied

    Signatures of Thermal Dilepton Radiation at RHIC

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    The properties of thermal dilepton production from heavy-ion collisions in the RHIC energy regime are evaluated for invariant masses ranging from 0.5 to 3 GeV. Using an expanding thermal fireball to model the evolution through both quark-gluon and hadronic phases various features of the spectra are addressed. In the low-mass region, due to an expected large background, the focus is on possible medium modifications of the narrow resonance structures from ω\omega and ϕ\phi mesons, whereas in the intermediate-mass region the old idea of identifying QGP radiation is reiterated including effects of chemical under-saturation in the early stages of central Au+Au collisions.Comment: 17 pages ReVTeX including 16 figure

    Structural basis for phosphorylation-dependent recruitment of tel2 to hsp90 by pih1

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    Client protein recruitment to the Hsp90 system depends on cochaperones that bind the client and Hsp90 simultaneously and facilitate their interaction. Hsp90 involvement in the assembly of snoRNPs, RNA polymerases, PI3-kinase-like kinases, and chromatin remodeling complexes depends on the TTT (Tel2-Tti1-Tti2), and R2TP complexes-consisting of the AAA-ATPases Rvb1 and Rvb2, Tah1 (Spagh/RPAP3 in metazoa), and Pih1 (Pih1D1 in humans)-that together provide the connection to Hsp90. The biochemistry underlying R2TP function is still poorly understood. Pih1 in particular, at the heart of the complex, has not been described at a structural level, nor have the multiple protein-protein interactions it mediates been characterized. Here we present a structural and biochemical analysis of Hsp90-Tah1-Pih1, Hsp90-Spagh, and Pih1D1-Tel2 complexes that reveal a domain in Pih1D1 specific for binding CK2 phosphorylation sites, and together define the structural basis by which the R2TP complex connects the Hsp90 chaperone system to the TTT complex

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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