Charge Particle Multiplicity and Transverse Energy Measurements in Au-Au collisions in PHENIX at RHIC

We present results on charged particle and transverse energy densities measured at mid-rapidity in Au-Au collisions at sqrt(s_{NN})=200 GeV. The mean transverse energy per charged particle is derived. The results are presented as a function of centrality, which is defined by the number of participating nucleons, and compared to results obtained in Au-Au collisions at sqrt{s_{NN})=130 GeV. A comparison with calculations from various theoretical models is performed.Comment: 4 pages, 5 figures. Talk presented at Quark Matter 2002, Nantes, France, July 18-24, 2002. To appear in the proceedings (Nucl. Phys. A

Direct Photons in Nuclear Collisions at FAIR Energies

Using the extrapolation of existing data estimations of prompt photon production at FAIR energies have been made. At $y=y_{c.m.}$ the rapidity density of prompt photons with $p_{t}>$ 1.5 GeV/c per central Au+Au event at 25 AGeV is estimated as $\sim 10^{-4}$ . With the planed beam intensity $10^{9}$ per second and 1% interaction probability, for 10% of most central events one can expect the prompt photon rate $\sim 10^{2}$ photons per second. Direct photons from the hadron scenario of ion collisions generated by the Hadron-String-Dynamics (HSD) transport approach with implemented meson scatterings $\pi\rho\to\pi\gamma, \pi\pi\to\rho\gamma$ have been analyzed. Photons from short-living resonances (e.g. $\omega \to \pi^{0} \gamma$) decaying during the dense phase of the collision should be considered as direct photons. They contribute significantly in the direct photon spectrum at $p_{t}=0.5 - 1$ GeV/c. At the FAIR energy 25 AGeV in Au+Au central collisions the HSD generator predicts, as a lower estimate, $\gamma_{direct}/\gamma_{\pi^{0}} \simeq$ 0.5% in the region $p_{t}=0.5 - 1$ GeV/c. At $p_{t}=1.5 - 2$ GeV/c $\gamma_{prompt}/\gamma_{\pi^{0}} \simeq$ 2%. Thermal direct photons have been evaluated with the Bjorken Hydro-Dynamics (BHD) model. The BHD spectra differ strongly from the HSD predictions. The direct photon spectrum is very sensitive to the initial temperature parameter $T_{0}$ of the model. The 10 MeV increase in the $T_{0}$ value leads to $\sim$ 2 times higher photon yield.Comment: 9 pages, 5 figures, Talk at the session of Russian Academy of Sciences, ITEP, Moscow, 26 - 30 November 200

Event-by-event fluctuations of average transverse momentum in central Pb+Pb collisions at 158 GeV per nucleon

We present first data on event-by-event fluctuations in the average transverse momentum of charged particles produced in Pb+Pb collisions at the CERN SPS. This measurement provides previously unavailable information allowing sensitive tests of microscopic and thermodynamic collision models and to search for fluctuations expected to occur in the vicinity of the predicted QCD phase transition. We find that the observed variance of the event-by-event average transverse momentum is consistent with independent particle production modified by the known two-particle correlations due to quantum statistics and final state interactions and folded with the resolution of the NA49 apparatus. For two specific models of non-statistical fluctuations in transverse momentum limits are derived in terms of fluctuation amplitude. We show that a significant part of the parameter space for a model of isospin fluctuations predicted as a consequence of chiral symmetry restoration in a non-equilibrium scenario is excluded by our measurement.Comment: 6 pages, 2 figures, submitted to Phys. Lett.

Centrality and sNNDependenceofthe\sqrt{s_{NN}} Dependence of the dE_{T}/d\etaand and dN_{ch}/d\eta$ in Heavy Ion Collisions at Mid-Rapidity

The PHENIX experiment at RHIC has measured transverse energy and charged particle multiplicity at mid-rapidity in Au + Au collisions at $\sqrt{s_{NN}}$ = 19.6, 130, 62.4 and 200 GeV as a function of centrality. The presented results are compared to measurements from other RHIC experiments, and experiments at lower energies. The $\sqrt{s_{NN}}$ dependence of $dE_{T}/d\eta$ and $dN_{ch}/d\eta$ per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of $dE_{T}/d\eta$ and $dN_{ch}/d\eta$ is similar at all measured incident energies. At RHIC energies the ratio of transverse energy per charged particle was found independent of centrality and growing slowly with $\sqrt{s_{NN}}$. A survey of comparisons between the data and available theoretical models is also presented.Comment: Proccedings of the Workshop: Focus on Multiplcity at Bari, Italy, June 17-19,2004. To be submitted to the Jornal of Physics, "Conference series". Includes: 20 Pages, 15 figures, 3 Tables, 80 Referencie

Attitude of young people under 30 towards the opportunities and obstacles of creating start-ups in Lithuania

Tyrimo objektas – jaunuolių iki 30 metų startuolių kūrimo galimybių ir kliūčių vertinimas Lietuvoje. Baigiamojo darbo tikslas - išsiaiškinti jaunuolių iki 30 metų požiūrį į startuolių kūrimo galimybes ir kliūtis Lietuvoje. Darbo metodologija – siekiant atlikti išsamų ir kokybišką bakalauro baigiamojo darbo tyrimą naudojami šie metodai: mokslinės literatūros analizė ir sintezė, mokslinės informacijos apibendrinimas, palyginimas, sisteminimas. Jos tikslas palyginti užsienio ir Lietuvos autorių straipsnius ir knygas, susijusias su startuolių kūrimu. Teorinėje baigiamojo bakalauro darbo dalyje aptariama startuolio samprata ir mokslininkų pateikiami startuolio veiklos etapai, įvardijamos dažniausios kliūtys, su kuriomis susiduria startuoliai bei pateikiamos ir aprašomos startuolių finansavimo alternatyvos. Toliau darbe aprašomi verslo inkubatoriai bei akseleratoriai, įsigilinta į situaciją Lietuvoje ir svarbiausią veiklą pirmuosiuose startuolio steigimo etapuose. Atlikus teorinę analizę susirinkta reikiama informacija praktinei darbo daliai. Empirinis tyrimas paremtas kiekybinių duomenų apdorojimo metodais. Darbe naudojami statistiniai metodai: moda, mediana, vidurkiai, „Spearman“ ryšiai bei „Cramers V“ priklausomybės. Susisteminti statistiniai duomenys pateikti lentelių ir paveikslų pavidalu, pagal juos suformuotos išvados bei rekomendacijos. Darbo pabaigoje pateikiama 20 svarbiausių šio darbo išvadų, taip pat pateikiamos rekomendacijos, šio darbo apribojimai, aktualumas bei tolesnės šio darbo plėtojimo galimybės.The object of the research is the assessment of opportunities and obstacles for the creation of start-ups of young people under the age of 30 in Lithuania. The aim of the final work is to find out the attitude of young people under 30 to the opportunities and obstacles of creating start-ups in Lithuania. Work methodology - to perform a comprehensive and high-quality bachelor's final work, these methods were implemented: analysis and synthesis of scientific literature, generalization of scientific information and comparison. It was also a purpose to compare articles and books by foreign and Lithuanian authors related to the creation of start-ups. The theoretical part of the bachelor's thesis discusses the concept of a start-up and the stages of the start-up activity presented by researchers, identifies the most common obstacles faced by start-ups, presents and describes alternatives for financing start-ups. The paper describes business incubators and accelerators, delves into the situation in Lithuania and the most important activities in the first stages of the start-up. After the theoretical analysis, all the needed information for the practical analysis preparation was gathered. Empirical research is made by a quantitative data processing method. These statistical methods are used in the work: moda, median, means, Spearman correlations and Cramers V dependencies. Systematised statistical data are presented in the form of tables and figures, conclusions and recommendations are formed according to them. At the end of the work, the 20 most important conclusions of this work are presented, as well as recommendations, limitations of this work, relevant and further development opportunities of this work.Ekonomikos ir vadybos fakulteta