Rapidity Dependence of High-pt Suppresion

The rapidity dependence of the nuclear modification factor in d-Au collaisions at sqrt(s) = 200 GeV at RHIC is discussed.Comment: To appear in the proceedings of the XIII International Workshop on Deep Inelastic Scattering (DIS 2005), Madison. 4 pages 4 figure

Stopping in Relativistic Heavy Ion Reactions - From SIS to RHIC

The status of stopping in heavy ion reactions is reviewed by comparing available data in pp, pA and AA systems over the energy regime sqrt(s_NN) ~ 2.5 - 130 GeV/c. The data consist of average rapidity losses, anti-proton over proton ratios, and net-baryon values at mid-rapidity. The overall features of nuclear stopping are reasonbly well described by simple extrapolations of pp, and pA collisions to AAComment: 10 pages incl. 8 figures. Proceedings of the 17th winter workshop on Nuclear Dynamics, Park City,Utah 200

Danish and British Protection from Disability Discrimination at Work - Past, Present and Future.

Denmark and the United Kingdom both became members of what is now the European Union (EU) in 1973 and are thus equally matched in terms of opportunity to bring their anti-discrimination laws into line with those of the EU and other supra-national bodies such as the United Nations (UN) and the Council of Europe. Our investigation, based on existing reports, academic analysis and case law rulings involving alleged discrimination on grounds of disability, has revealed some major differences in the level of protection provided by each country’s legislature and judicature, but also by other mechanisms that extend beyond these traditional measures, such as workplace collective agreements.While the UK has a long history of supporting people with disabilities by legislating in all aspects of society, Denmark has been at the forefront with social mechanisms, but has been reluctant to ensure equality in the labour market. However, both countries have been equally unsuccessful in ensuring opportunities for disabled workers, and consideration is given here as to whether one system of dealing with this is better than another. We conclude that neither strict regulation imposed by the EU or national governments, nor the laissez-faire method of leaving the level of protection to be decided by collective agreement is entirely satisfactory. A different perspective altogether would be to adopt the substantive diversity theory which would focus on a person’s abilities and what they are able to do, and to gear society to embrace diversities, as the Danish employment agency Specialisterne has done so successfully in the case of adults with autism. Countries such as Denmark and the UK have much to learn from each other to tackle successfully this last bastion of workplace inequality

The ring imaging Cherenkov detector for the BRAHMS experiment at RHIC

A ring imaging Cherenkov counter, to be read out by four 100-channel PMTs, is a key element of the BRAHMS experiment. We report here the most recent results obtained tested at the BNL AGS using several radiator gases, including the heavy fluorocarbon C4F10. Ring radii were measured for different particles (pions, muons, and electrons) for momenta ranging from 2 to 12 GeV/c employing pure C4F10 as radiator.Comment: 3 pages 3 figure

Proton stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A GeV/c

The shape of proton rapidity distributions is analysed in terms of their Gaussian components, and the average rapidity loss is determined in order to estimate the amount of stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A GeV/c. Three Gaussians correspond to the nuclear transparency and describe well all peripheral and also C+C central collisions. Two-component shape is obtained in case of d+C and C+Ta central collisions. Finally one Gaussian, found in d+Ta central collisions, corresponds to the full stopping. The calculated values of the average rapidity loss support the qualitative relationship between the number of Gaussian components and the corresponding stopping power. It is also observed, in central collisions, that the average rapidity loss increases with the ratio of the number of target and the number of projectile participants.Comment: 9 pages REVTeX, 1 PS figure replaced, to be published in Phys.Rev.

Single-Transverse Spin Asymmetry in Dijet Correlations at Hadron Colliders

We present a phenomenological study of the single-transverse spin asymmetry in azimuthal correlations of two jets produced nearly "back-to-back" in pp collisions at RHIC. We properly take into account the initial- and final-state interactions of partons that can generate this asymmetry in QCD hard-scattering. Using distribution functions fitted to the existing single-spin data, we make predictions for various weighted single-spin asymmetries in dijet correlations that are now readily testable at RHIC.Comment: 14 pages, 2 figure

The Spectator Electromagnetic Effect on Charged Pion Spectra in Peripheral Ultrarelativistic Heavy-Ion Collisions

We estimate the electromagnetic effect of the spectator charge on the momentum spectra of $\pi^+$ and $\pi^-$ produced in peripheral Pb+Pb collisions at SPS energies. We find that the effect is large and results in strongly varying structures in the $x_F$ dependence of the $\pi^+/\pi^-$ ratio, especially at low transverse momenta where a deep valley in the above ratio is predicted at $x_F \sim$ 0.15 -- 0.20. It appears that the effect depends on initial conditions. Thus, it provides new information on the space and time evolution of the non-perturbative pion creation process.Comment: 20 pages and 8 figure

Excitation Functions of Stopping Power and Flow in Relativistic Heavy-Ion Collisions

Using a relativistic transport (ART) model, we study the stopping power, the formation of superdense hadronic matter as well as the strength of transverse and radial flow in central Au+Au collisions at beam momentum from 2 to 12 GeV/c per nucleon. We find that complete stopping is achieved in the whole beam momentum range. In particular, the proton rapidity distribution scaled by the beam rapidity is independent of the beam momentum, and this is in agreement with the experimental findings. Also, a large volume of superdense hadronic matter with a local energy density exceeding that expected for the transition of a hadronic matter to the quark-gluon plasma is formed in collisions at beam momenta greater than 8 GeV/c per nucleon. Furthermore, it is found that the transverse flow in these collisions is sensitive to the nuclear equation of state and decreases with increasing beam momentum. On the other hand, the radial flow is insensitive to the equation of state, and its strength increases with beam momentum.Comment: Talk given at NN97, Gatlinburg, Tennessee June 2-6,1997. To appear in the proc. in Nucl. Phys.

Density and Boundary Effects on Pion Distributions in Relativistic Heavy--Ion Collisions

We compute the pion inclusive momentum distribution in a heavy-ion collision, assuming thermal equilibrium and accounting for boundary effects at the time of decoupling. We calculate the chemical potential corresponding to an average pion multiplicity in central collisions and explore the consequences of having the pion system produced close to the critical temperature for Bose-Einstein condensation.Comment: Latex, 4 pages, 4 figures. Submitted to Phys. Lett.