Yano-Koonin-Podgoretskii Parametrisation of the Hanbury Brown-Twiss Correlator

The Yano-Koonin-Podgoretskii (YKP) parametrisation of Hanbury Brown-Twiss (HBT) two-particle correlation functions opens new strategies for extracting the emission duration and testing the longitudinal expansion in heavy-ion collisions. Based on the recently derived model-independent expressions, we present a detailed parameter study of the YKP parameters for a finite, hydrodynamically expanding source model of heavy-ion collisions. For the class of models studied here, we show that the three YKP radius parameters have an interpretation as longitudinal extension, transverse extension and emission duration of the source in the YKP frame. This frame is specified by the fourth fit parameter, the Yano-Koonin velocity which describes to a good approximation the velocity of the fluid element with highest emissivity and allows to test for the longitudinal expansion of the source. Deviations from this interpretation of the YKP parameters are discussed quantitatively.Comment: 38 pages, REVTeX, 11 PS-figures, to be published in Z.Phys.

Space-time Characteristics of the Fireball from HBT Interferometry

We present the Yano-Koonin-Podgoretskii parametrisation of the correlation function. Compared to the conventionally used Cartesian parametrisation, this one provides more straightforward measurement of the duration of the emission process in the fireball and a clearer signal of the longitudinal expansion, which is expected in ulrarelativistic heavy ion collisions.Comment: 13 pages LaTeX,3 figures incl. with epsf-style. Proceedings of "Heavy Ion Workshop on Particle Physics", Sept. 2.-6., 1996, Bratislava, Slovakia, misprint in Eq.(27) correcte

HBT: A (mostly) experimental overview

I will present a review of the field of Hanbury Brown-Twiss interferometry in relativistic heavy-ion collisions. The "HBT puzzle" is explored in detail, emphasizing recent theoretical attempts to understand the persisting puzzle. I also present recent experimental results on azimuthally sensitive HBT, HBT of direct photons, and some surprises in the comparison of HBT results from p+p and Au+Au collisions at RHIC.Comment: 8 pages, 3 figures. Proceedings of the Quark Matter 2004 conference (Oalkland, CA, USA, January 2004

Transport model analysis of the transverse momentum and rapidity dependence of pion interferometry at SPS energies

Based on the UrQMD transport model, the transverse momentum and the rapidity dependence of the Hanbury-Brown-Twiss (HBT) radii $R_L$, $R_O$, $R_S$ as well as the cross term $R_{OL}$ at SPS energies are investigated and compared with the experimental NA49 and CERES data. The rapidity dependence of the $R_L$, $R_O$, $R_S$ is weak while the $R_{OL}$ is significantly increased at large rapidities and small transverse momenta. The HBT "life-time" issue (the phenomenon that the calculated $\sqrt{R_O^{2}-R_S^{2}}$ value is larger than the correspondingly extracted experimental data) is also present at SPS energies.Comment: 17 pages, 11 figure

A comprehensive description of multiple observables in heavy-ion collisions at SPS

Combining and expanding on work from previous publications, a model for the evolution of ultrarelativistic heavy-ion collisions at the CERN SPS for 158 AGeV beam energy is presented. Based on the assumption of thermalization and a parametrization of the space-time expansion of the produced matter, this model is able to describe a large set of observables including hadronic momentum spectra, correlations and abundancies, the emission of real photons, dilepton radiation and the suppression pattern of charmonia. Each of these obervables provides unique capabilities to study the reaction dynamics and taken together they form a strong and consistent picture of the evolving system. Based on the emission of hard photons, we argue that a strongly interacting, hot and dense system with temperatures above 250 MeV has to be created early in the reaction. Such a system is bound to be different from hadronic matter and likely to be a quark-gluon plasma, and we find that this assumption is in line with the subsequent evolution of the system that is reflected in other observables.Comment: 21 pages, 10 figures, submitted to J. Phys.

Early collective expansion: Relativistic hydrodynamics and the transport properties of QCD matter

Relativistic hydrodynamics for ideal and viscous fluids is discussed as a tool to describe relativistic heavy-ion collisions and to extract transport properties of the quark-gluon plasma from experimentally measured hadron momentum spectra.Comment: Review article, 54 pages, 25 figure

Dual antiplatelet therapy duration after coronary stenting in clinical practice: results of an EAPCI survey

Aims: Our aim was to report on a survey initiated by the EuropeanAssociation of Percutaneous Cardiovascular Interventions (EAPCI) concerning opinion on the evidence relating to dual antiplatelet therapy (DAPT) duration after coronary stenting.Methods and results: Results from three randomised clinical trials were scheduled to be presented at the American Heart Association Scientific Sessions 2014 (ARIA 2014). A web-based survey was distributed to all individuals registered in the EuroIntervention mailing list (n=15,200) both before and after ARIA 2014. A total of 1,134 physicians responded to the first (i.e., before AHA 2014) and 542 to the second (i.e., after ARIA 2014) survey. The majority of respondents interpreted trial results consistent with a substantial equipoise regarding the benefits and risks of an extended versus a standard DAPT strategy. Two respondents out of ten believed extended DAFT should be implemented in selected patients. After ARIA 2014, 46.1% of participants expressed uncertainty about the available evidence on DAFT duration, and 40.0% the need for clinical guidance.Conclusions: This EAPCI survey highlights considerable uncertainty within the medical community with regard to the optimal duration of DAFT after coronary stenting in the light of recent reported trial results. Updated recommendations for practising physicians to guide treatment decisions in routine clinical practice should be provided by international societies