The Origin of Transverse Flow at the SPS

We study the transverse expansion in central Pb+Pb collisions at the CERN SPS. Strong collective motion of hadrons can be created. This flow is mainly due to meson baryon rescattering. It allows to study the angular distribution of intermediate mass meson baryon interactions.Comment: submitted to Phys. Lett.

Systematics of pion emission in heavy ion collisions in the 1A GeV regime

Using the large acceptance apparatus FOPI, we study pion emission in the reactions (energies in GeV/nucleon are given in parentheses): 40Ca+40Ca (0.4, 0.6, 0.8, 1.0, 1.5, 1.93), 96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0, 1.5), 197Au+197Au (0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The observables include longitudinal and transverse rapidity distributions and stopping, polar anisotropies, pion multiplicities, transverse momentum spectra, ratios for positively and negatively charged pions of average transverse momenta and of yields, directed flow, elliptic flow. The data are compared to earlier data where possible and to transport model simulations.Comment: 56 pages,42 figures; to be published in Nuclear Physics

Nucleon matrix elements and baryon masses in the Dirac orbital model

Using the expansion of the baryon wave function in a series of products of single quark bispinors (Dirac orbitals), the nonsinglet axial and tensor charges of a nucleon are calculated. The leading term yields $g_A = 1.27$ in good agreement with experiment. Calculation is essentially parameter-free and depends only on the strong coupling constant value $\alpha_s$. The importance of lower Dirac bispinor component, yielding 18% to the wave function normalization is stressed. As a check, the baryon decuplet masses in the formalism of this model are also computed using standard values of the string tension $\sigma$ and the strange quark mass $m_s$; the results being in a good agreement with experiment.Comment: 8 pages, 2 tables; LaTeX2

Mental health interventions and priorities for research for adult survivors of torture and systematic violence: a review of the literature

This research describes the development and findings of a literature review and analysis meant to inform the international torture and trauma treatment community. The review focuses on interventions that have been used among populations affected by torture, based on a review of journals indexed in commonly used search engines. Work on the review began in September 2008 and continued to be updated until March 2014. In total, 88 studies of interventions for torture victims were identified. Studies ranged from randomized controlled trials utilizing evidence-based treatments to case studies employing non-structured, supportive therapies. Based on the results of the analysis, we have included recommendations for interventions that demonstrate effectiveness in treating survivors of torture and other systematic violence who suffer from PTSD, depression, and anxiety.  Priorities for mental health research for survivors of torture and other systematic violence are also recommended. &nbsp

Strangeness dynamics in relativistic nucleus-nucleus collision

We investigate hadron production as well as transverse hadron spectra in nucleus-nucleus collisions from 2 $A\cdot$GeV to 21.3 $A\cdot$TeV within two independent transport approaches (UrQMD and HSD) that are based on quark, diquark, string and hadronic degrees of freedom. The comparison to experimental data demonstrates that both approaches agree quite well with each other and with the experimental data on hadron production. The enhancement of pion production in central Au+Au (Pb+Pb) collisions relative to scaled $pp$ collisions (the 'kink') is well described by both approaches without involving any phase transition. However, the maximum in the $K^+/\pi^+$ ratio at 20 to 30 A$\cdot$GeV (the 'horn') is missed by $\sim$ 40%. A comparison to the transverse mass spectra from $pp$ and C+C (or Si+Si) reactions shows the reliability of the transport models for light systems. For central Au+Au (Pb+Pb) collisions at bombarding energies above $\sim$ 5 A$\cdot$GeV, however, the measured $K^{\pm}$ $m_{T}$-spectra have a larger inverse slope parameter than expected from the calculations. The approximately constant slope of $K^\pm$ spectra at SPS (the 'step') is not reproduced either. Thus the pressure generated by hadronic interactions in the transport models above $\sim$ 5 A$\cdot$GeV is lower than observed in the experimental data. This finding suggests that the additional pressure - as expected from lattice QCD calculations at finite quark chemical potential and temperature - might be generated by strong interactions in the early pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions.Comment: 10 pages, 5 figures, Invited talk presented by H. Stocker at ERICE-2003 (Sep. 2003, Erice, Italy), to be published in Prog. Part. Nucl. Phys. 52 (2004

Systematic Study of the Kaon to Pion Multiplicity Ratios in Heavy-Ion Collisions

We present a systematic study of the kaon to pion multiplicity ratios (K+/pi+ and K-/pi-) in heavy-ion collisions from AGS to RHIC energy using the Relativistic Quantum Molecular Dynamics (RQMD) model. The model satisfactorily describes the available experimental data on K+/pi+ and K-/pi-. Within the model, we find that the strong increase of the ratios with the number of participants is mainly due to hadronic rescattering of produced mesons with ingoing baryons and their resonances. The enhancement of K/pi in heavy-ion collisions with respect to elementary p+p interactions is larger at AGS energy than SPS energy, and decreases smoothly with bombarding energy. The total multiplicity ratios at RHIC energy are predicted by RQMD to be K+/pi+ = 0.19 and K-/pi- = 0.15.Comment: 10 pages, 8 figures, RevTeX style. A section is added to discuss effects of rope formatio

Simulation of Atmospheric Muon and Neutrino Fluxes with CORSIKA

The fluxes of atmospheric muons and neutrinos are calculated by a three dimensional Monte Carlo simulation with the air shower code CORSIKA using the hadronic interaction models DPMJET, VENUS, GHEISHA, and UrQMD. For the simulation of low energy primary particles the original CORSIKA has been extended by a parametrization of the solar modulation and a microscopic calculation of the directional dependence of the geomagnetic cut-off functions. An accurate description for the geography of the Earth has been included by a digital elevation model, tables for the local magnetic field in the atmosphere, and various atmospheric models for different geographic latitudes and annual seasons. CORSIKA is used to calculate atmospheric muon fluxes for different locations and the neutrino fluxes for Kamioka. The results of CORSIKA for the muon fluxes are verified by an extensive comparison with recent measurements. The obtained neutrino fluxes are compared with other calculations and the influence of the hadronic interaction model, the geomagnetic cut-off and the local magnetic field on the neutrino fluxes is investigated.Comment: revtex, 19 pages, 19 Postscript figures, submitted to Phys. Rev.

Can a leader be seen as too ethical? The curvilinear effects of ethical leadership

Ethical leadership predicts important organizational outcomes such as decreased deviant and increased organizational citizenship behavior (OCB). We argued that due to the distinct nature of these two types of employee behaviors, ethical leadership decreases deviance in a linear manner (i.e., more ethical leadership leading to less deviance), but we expected ethical leadership to reveal a curvilinear relationship with respect to OCB. Specifically, we expected that, at lower levels, ethical leadership promotes OCB. However, at high levels, ethical leadership should lead to a decrease in these behaviors. We also examined a mechanism that explains this curvilinear pattern, that is, followers’ perceptions of moral reproach. Our predictions were supported in three organizational field studies and an experiment. These findings offer a better understanding of the processes that underlie the workings of ethical leadership. They also imply a dilemma for organizations in which they face the choice between limiting deviant employee behavior and promoting OCB

Phi Mesons from a Hadronic Fireball

Production of $\phi$ mesons is considered in the course of heavy-ion collisions at SPS energies. We investigate the possible difference in momentum distributions of $\phi$ mesons measured via their leptonic ($\mu^+\mu^-$) and hadronic ($K^+K^-$) decays. Rescattering of secondary kaons in the dense hadron gas together with the influence of in-medium kaon potential can lead to a relative decrease of a $\phi$ yield observed in the hadronic channel. We analyze how the in-medium modifications of meson properties affect apparent - reconstructed momentum distributions of $\phi$ mesons. Quantitative results are presented for central Pb+Pb collisions at $E_{beam}=158 GeV/A$.Comment: style Revtex4,9 pages, 5 figures. submitted to Phys. Rev.

Particlization in hybrid models

In hybrid models, which combine hydrodynamical and transport approaches to describe different stages of heavy-ion collisions, conversion of fluid to individual particles, particlization, is a non-trivial technical problem. We describe in detail how to find the particlization hypersurface in a 3+1 dimensional model, and how to sample the particle distributions evaluated using the Cooper-Frye procedure to create an ensemble of particles as an initial state for the transport stage. We also discuss the role and magnitude of the negative contributions in the Cooper-Frye procedure.Comment: 18 pages, 28 figures, EPJA: Topical issue on "Relativistic Hydro- and Thermodynamics"; version accepted for publication, typos and error in Eq.(1) corrected, the purpose of sampling and change from UrQMD to fluid clarified, added discussion why attempts to cancel negative contributions of Cooper-Frye are not applicable her