Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment

We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta < 7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations for the response of the CASTOR calorimeter, and in particular to the traversal of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR

CASTOR: Centauro and Strange Object Research in nucleus-nucleus collisions at LHC

We describe the CASTOR detector designed to probe the very forward, baryon-rich rapidity region in nucleus-nucleus collisions at the LHC. We present a phenomenological model describing the formation of a QGP fireball in a high baryochemical potential environment, and its subsequent decay into baryons and strangelets. The model explains Centauros and the long-penetrating component and makes predictions for the LHC. Simulations of Centauro-type events were done. To study the response of the apparatus to new effects different exotic species (DCC, Centauros, strangelets etc.) were passed through the deep calorimeter. The energy deposition pattern in the calorimeter appears to be a new clear signature of the QGP.Comment: Talk given by E. Gladysz-Dziadus for the CASTOR group, Intern. Workshop on Nuclear Theory, 10-15 June, 2002, Bulgaria, Rila Mountains, 15 pages, 14 figure

Particle abundances and spectra in the hydrodynamical description of relativistic nuclear collisions with light projectiles

We show that a hydrodynamical model with continuous particle emission instead of sudden freeze out may explain both the observed strange particle and pion abundances and transverse mass spectra for light projectile at SPS energy. We found that the observed enhancement of pion production corresponds, within the context of continuous emission, to the maximal entropy production.Comment: 11 pages, 2 figure

Timbre brownfield prioritization tool to support effective brownfield regeneration.

In the last decade, the regeneration of derelict or underused sites, fully or partly located in urban areas (or so called “brownfields”), has become more common, since free developable land (or so called “greenfields”) has more and more become a scare and, hence, more expensive resource, especially in densely populated areas. Although the regeneration of brownfield sites can offer development potentials, the complexity of these sites requires considerable efforts to successfully complete their revitalization projects and the proper selection of promising sites is a pre-requisite to efficiently allocate the limited financial resources. The identification and analysis of success factors for brownfield sites regeneration can support investors and decision makers in selecting those sites which are the most advantageous for successful regeneration. The objective of this paper is to present the Timbre Brownfield Prioritization Tool (TBPT), developed as a web-based solution to assist stakeholders responsible for wider territories or clusters of brownfield sites (portfolios) to identify which brownfield sites should be preferably considered for redevelopment or further investigation. The prioritization approach is based on a set of success factors properly identified through a systematic stakeholder engagement procedure. Within the TBPT these success factors are integrated by means of a Multi Criteria Decision Analysis (MCDA) methodology, which includes stakeholders' requalification objectives and perspectives related to the brownfield regeneration process and takes into account the three pillars of sustainability (economic, social and environmental dimensions). The tool has been applied to the South Moravia case study (Czech Republic), considering two different requalification objectives identified by local stakeholders, namely the selection of suitable locations for the development of a shopping centre and a solar power plant, respectively. The application of the TBPT to the case study showed that it is flexible and easy to adapt to different local contexts, allowing the assessors to introduce locally relevant parameters identified according to their expertise and considering the availability of local data

Disruption of Growth Hormone Receptor Prevents Calorie Restriction from Improving Insulin Action and Longevity

Most mutations that delay aging and prolong lifespan in the mouse are related to somatotropic and/or insulin signaling. Calorie restriction (CR) is the only intervention that reliably increases mouse longevity. There is considerable phenotypic overlap between long-lived mutant mice and normal mice on chronic CR. Therefore, we investigated the interactive effects of CR and targeted disruption or knock out of the growth hormone receptor (GHRKO) in mice on longevity and the insulin signaling cascade. Every other day feeding corresponds to a mild (i.e. 15%) CR which increased median lifespan in normal mice but not in GHRKO mice corroborating our previous findings on the effects of moderate (30%) CR on the longevity of these animals. To determine why insulin sensitivity improves in normal but not GHRKO mice in response to 30% CR, we conducted insulin stimulation experiments after one year of CR. In normal mice, CR increased the insulin stimulated activation of the insulin signaling cascade (IR/IRS/PI3K/AKT) in liver and muscle. Livers of GHRKO mice responded to insulin by increased activation of the early steps of insulin signaling, which was dissipated by altered PI3K subunit abundance which putatively inhibited AKT activation. In the muscle of GHRKO mice, there was elevated downstream activation of the insulin signaling cascade (IRS/PI3K/AKT) in the absence of elevated IR activation. Further, we found a major reduction of inhibitory Ser phosphorylation of IRS-1 seen exclusively in GHRKO muscle which may underpin their elevated insulin sensitivity. Chronic CR failed to further modify the alterations in insulin signaling in GHRKO mice as compared to normal mice, likely explaining or contributing to the absence of CR effects on insulin sensitivity and longevity in these long-lived mice

CASTOR: A Forward Detector for the Identification of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC

Presentation made at the XXVIIIth Symposium on Multiparticle Dynamics, 6-11 September 1998, Delphi and published in World ScientificThe physics motivation for a very forward detector to be employed in heavy ion collisions at the CERN LHC is discussed. A phenomenological model describing the formation and decay of a Centauro fireball in nucleus-nucleus collisions is presented. The CASTOR detector which is aimed to measure the hadronic and photonic content of an interaction and to identify deeply penetrating objects in the very forward, baryon-rich phase space 5.6eta7.2 in an event-by-event mode is described. Results of simulations of the expected response of the calorimeter and, in particular, to the passage of strangelets, are presented

Formation of Centauro in Pb+Pb Collisions at the LHC and their Identification in the ALICE Experiment

Presentation made at EPS-HEP'99 and submitted to IOP PublishingWe present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and strangeness-rich objects. We describe the CASTOR calorimeter for the ALICE experiment at the LHC. CASTOR will probe the very forward, baryon-rich phase space 5.6eta7.2 in 5.5xA TeV central Pb+Pb collisions. We present results of simulations for the response of CASTOR to the passage of strangeness-rich objects

Thermal phenomenology of hadrons from 200 AGeV S+S collisions

We develop a complete and consistent description for the hadron spectra from heavy ion collisions in terms of a few collective variables, in particular temperature, longitudinal and transverse flow. To achieve a meaningful comparison with presently available data, we also include the resonance decays into our picture. To disentangle the influences of transverse flow and resonance decays in the $m_T$-spectra, we analyse in detail the shape of the $m_T$-spectra.Comment: 31 pages, 13 figs in seperate uuencoded file, for LaTeX, epsf.sty and dvips, TPR-93-16 and BNL-(no number yet

Remnants of Initial Anisotropic High Energy Density Domains in Nucleus-Nucleus Collisions

Anisotropic high energy density domains may be formed at early stages of ultrarelativistic heavy ion collisions, e.g. due to phase transition dynamics or non-equilibrium phenomena like (mini-)jets. Here we investigate hadronic observables resulting from an initially created anisotropic high energy density domain. Based on our studies using a transport model we find that the initial anisotropies are reflected in the freeze-out multiplicity distribution of both pions and kaons due to secondary hadronic rescattering. The anisotropy appears to be stronger for particles at high transverse momenta. The overall kaon multiplicity increases with large fluctuations of local energy densities, while no change has been found in the pion multiplicity.Comment: Submitted to PR

Search for the QCD critical point in nuclear collisions at the CERN SPS

Pion production in nuclear collisions at the SPS is investigated with the aim to search, in a restricted domain of the phase diagram, for power-laws in the behavior of correlations which are compatible with critical QCD. We have analyzed interactions of nuclei of different size (p+p, C+C, Si+Si, Pb+Pb) at 158$A$ GeV adopting, as appropriate observables, scaled factorial moments in a search for intermittent fluctuations in transverse dimensions. The analysis is performed for $\pi^+\pi^-$ pairs with invariant mass very close to the two-pion threshold. In this sector one may capture critical fluctuations of the sigma component in a hadronic medium, even if the $\sigma$-meson has no well defined vacuum state. It turns out that for the Pb+Pb system the proposed analysis technique cannot be applied without entering the invariant mass region with strong Coulomb correlations. As a result the treatment becomes inconclusive in this case. Our results for the other systems indicate the presence of power-law fluctuations in the freeze-out state of Si+Si approaching in size the prediction of critical QCD.Comment: 31 pages, 11 figure