On energy densities reached in heavy-ion collisions at the CERN SPS

We present a few estimates of energy densities reached in heavy-ion collisions at the CERN SPS. The estimates are based on data and models of proton-nucleus and nucleus-nucleus interactions. In all of these estimates the maximum energy density in central Pb+Pb interactions is larger than the critical energy density GeV/fm³ following from lattice gauge theory computations. In estimates which we consider as realistic the maximum energy density is about . In this way our analysis gives some support to claims that deconfined matter has been produced at the CERN SPS. Any definite statement requires a deeper understanding of formation times of partons and hadrons in nuclear collisions. We also compare our results with implicit energy estimates contained in earlier models of anomalous suppression in nuclear collisions. Received: 3 February 2003 / Revised version: 5 March 2003 / Published online: 5 May 2003     

Production of biologically inert Teflon thin layers on the surface of allergenic metal objects by pulsed laser deposition technology

Allergic-type diseases are current nowadays, and they are frequently caused by certain metals. We demonstrated that the metal objects can be covered by Teflon protective thin layers using a pulsed laser deposition procedure. An ArF excimer laser beam was focused onto the surface of pressed PTFE powder pellets; the applied fluences were 7.5–7.7 J/cm². Teflon films were deposited on fourteen-carat gold, silver and titanium plates. The number of ablating pulses was 10000. Post-annealing of the films was carried out in atmospheric air at oven temperatures between 320 and 500 °C. The thickness of the thin layers was around 5 μm. The prepared films were granular without heat treatment or after annealing at a temperature below 340 °C. At 360 °C a crystalline, contiguous, smooth, very compact and pinhole-free thin layer was produced; a melted and re-solidified morphology was observed above 420 °C. The adhesion strength between the Teflon films and the metal substrates was determined. This could exceed 1–4 MPa depending on the treatment temperature. It was proved that the prepared Teflon layers can be suitable for prevention of contact between the human body and allergen metals and so for avoidance of metal allergy. Received: 12 June 2002 / Accepted: 13 June 2002 / Published online: 4 November 2002 RID="*" ID="*"Corresponding author. E-mail: bhopp@physx.u-szeged.hu     

On the one loop equivalence of dual σ models

It is shown that in the one loop order of perturbation theory the coupling constant and parameter(s) of an (Abelian T) dual sigma model get renormalized in the same way as in the ‘original’ model.     

Spectroscopy of neutron deficient 65Ge

Excited states of ⁶⁵Ge were populated via the ¹²C + ⁵⁸Ni (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction channel separation. On the basis of γγ-coincidence relations and angular distribution ratios a significantly extended level scheme was constructed up to E _x = 9 MeV and J ^π = (33/2^?). The low-energy states of the nucleus are discussed in the framework of the interacting boson-fermion model.     

Compatibility and Marginality

We present a way of introducing joint distibution function and its marginal distribution functions for non-compatible observables. Each such marginal distribution function has the property of commutativity. Models based on this approach can be used to better explain some classical phenomena in stochastic processes.     

Open charm production from d + Au collisions in STAR

Charmed hadrons are interesting observables in heavy ion collisions. They are becoming more accessible to experimental scrutiny at RHIC energies due to the increased production cross-section of charm with the larger centre-of-mass energy available at RHIC compared to SPS. One source of interest in charm production is due to the fact that gluon fusion dominates the charm production cross-section at high energy. Hence, a measurement of charm hadrons is directly sensitive to the gluon distributions of the colliding particles. In addition, any measurement of production at RHIC, and more importantly any observed suppression, must be compared to the overall production of pairs. A systematic study of charmed hadrons in all collision systems available at RHIC is therefore an invaluable experimental tool in the characterization of the matter produced at RHIC. In particular, d + Au collisions are a necessary step for the comparison of any possible modification of charm production in Au + Au collisions. We present preliminary results on D meson production from d + Au collisions in STAR at = 200 . Arrival of the final proofs: 26 July 2005 PACS: 13.20.Fc, 13.25.Ft, 25.75.-q, 24.85. + p     

Strong approximation of empirical kac processes

Summary A strong approximation result is derived for the Poisson sample size empirical characteristic process. Work done while the author was on leave from Szeged University and a Visiting Scientist at Carleton University, supported by Canadian N.R.C. operating grants of D. A. Dawson and J. N. K. Rao.