538 research outputs found
Hadron ratio fluctuations in heavy-ion collisions
No full textThe first measurement of the fluctuation of the kaon-to-proton ratio in relativistic heavy-ion collisions is presented. This thesis details the analysis procedure for identifying kaons and protons using the NA49 experiment at CERN-SPS and discusses the results in the context of the current state of the field
Probing the quark-gluon phase transition using energy and system-size dependence of long-range multiplicity correlations in heavy ion collisions from the STAR experiment
No full textEnergy and system size dependence study of the percolation phase transition
No full textMultiparticle production at high energies is described in terms of color strings stretched between the projectile and target. As the string density increases, overlap in the transverse plane leads to cluster formation. At some critical density a macroscopic cluster appears, spanning the entire system. This marks the percolation phase transition. Data from root(NN)-N-S = 200 GeV p+p, d+Au and Au+Au collisions at RHIC has been analyzed using the STAR detector to obtain the percolation density parameter, eta. The particle p(T) spectrum from 200 GeV p+p data is parametrized using a power law. Values of the fit parameters are used in the d+Au and Au+Au analysis. For 200 GeV Au+Au collisions, the value of eta is found to lie above the critical percolation threshold, while for other collision systems and energies, it is below the critical value. This supports the idea of string percolation, which at high enough string density is a possible mechanism to explore the hadronic phase transition to a quark-gluon plasma
Lesões laríngeas após intubação orotraqueal.
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Departamento de Clínica Médica, Curso de Medicina, Florianópolis, 199
Transverse momentum distributions and string percolation study in p+p, d+Au and Au+Au collisions at square rootsNN = 200 GeV
No full textMultiparticle production at high energies is described in terms of color strings stretched between the projectile and target. As string density increases, overlap among the strings leads to cluster formation. At some critical density, a macroscopic cluster appears, spanning the entire system. This marks the percolation phase transition. Data from p+p, d+Au and Au+Au collisions at 200 GeV has been analyzed using the STAR detector to obtain the percolation density parameter, eta. For 200 GeV Au+Au collisions, the value of h is found to lie above the critical percolation threshold, while for 200 GeV d+Au collisions it is below the critical value. This supports the idea of string percolation, which at high enough string density is a possible mechanism to explore the hadronic phase transition to a quark-gluon plasma
Fluctuations and correlations from microscopic transport theory
No full textThe multiplicity fluctuations in A+A collisions at SPS and RHIC energies are studied within the HSD transport approach. We find a dominant role of the fluctuations in the nucleon participant number for the final fluctuations. In order to extract physical fluctuations one should decrease the fluctuations in the participants number. This can be done considering very central collisions. The system size dependence of the multiplicity fluctuations in central A+A collisions at the SPS energy range – obtained in the HSD and UrQMD transport models – is presented. The results can be used as a ‘background’ for experimental measurements of fluctuations as a signal of the critical point. Event-by-event fluctuations of the K/p , K/p and p/p ratios in A+A collisions are also studied. Event-by-event fluctuations of the kaon to pion number ratio in nucleus-nucleus collisions are studied for SPS and RHIC energies. We find that the HSD model can qualitatively reproduce the measured excitation function for the K/p ratio fluctuations in central Au+Au (or Pb+Pb) collisions from low SPS up to top RHIC energies. The forward-backward correlation coefficient measured by the STAR Collaboration in Au+Au collisions at RHIC is also studied. We discuss the effects of initial collision geometry and centrality bin definition on correlations in nucleus-nucleus collisions. We argue that a study of the dependence of correlations on the centrality bin definition as well as the bin size may distinguish between these ‘trivial’ correlations and correlations arising from ‘new physics’. 5th International Workshop on Critical Point and Onset of Deconfinement - CPOD 2009, June 08 - 12 2009 Brookhaven National Laboratory, Long Island, New York, US
«ЛИХВАРСЬКИЙ СПРИТ І ШАХРАЙСЬКА ХИТРІСТЬ»: СТАНІСЛАВ ТАРНОВСЬКИЙ ПРО ТРАНСФОРМАЦІЮ ЗАМОЖНОЇ ШЛЯХТИ ГАЛИЧИНИ В УМОВАХ СТАНОВЛЕННЯ ВІЛЬНОРИНКОВОГО СУСПІЛЬСТВА
No full textThe article is devoted to the analysis of the essay “Portions” (“Porcyi”) authored by the famous Polish scientist, politician and publicist S. Tarnowski (1837-1917), which was published in November 1874 and revealed changes in social position, economic activity and behavior of wealthy Galician nobles, who, taking advantage of the plight of the peasantry, were actively engaged in usury, earning a solid income. The author states that remaining outside the “noble origin of the owners of estates”, these nobles actually turned into rural extortionists, who are essentially no different from the representatives of the “merchant’s craft” (commissioners, brokers, moneylenders, etc.), genus classes which did not provide for honor and conscience. This, according to S. Tarnowsky, caused enormous damage to the “Polish cause”, as it destroyed the barely planned agreement between the nobility and the peasantry.Стаття присвячена аналізу есе «Порції» («Porcyi») авторства відомого польського науковця, політика і публіциста С. Тарновського (1837-1917 рр.), яке було опубліковане у листопаді 1874 р. і розкривало зміни в соціальній позиції, економічній діяльності і поведінці заможних галицьких шляхтичів, які, використовуючи нужденне становище селянства, активно займались лихварством, одержуючи солідні прибутки. Автор констатує, що залишаючись зовні «благородного походження власниками маєтків», ці шляхтичі насправді перетворились на сільських здирників, що за своєю сутністю нічим не відрізняються від представників «купецького ремесла» (комісіонерів, маклерів, лихварів і ін.), рід занять яких не передбачав честі й совісті. Це, на думку С. Тарнавського, завдавало величезної шкоди «польській справі», оскільки руйнувало ледь намічену згоду між шляхтою і селянством
Transverse momentum distributions and string percolation study in p+p, d+Au and Au+Au collisions at root S-NN=200 GeV
No full textMultiparticle production at high energies is described in terms of color strings stretched between the projectile and target. As string density increases, overlap among the strings leads to cluster formation. At some critical density, a macroscopic cluster appears, spanning the entire system. This marks the percolation phase transition. Data from p+p, d + Au and Au + Au collisions at 200 GeV has been analyzed using the STAR detector to obtain the percolation density parameter, eta. For 200 GeV Au+Au collisions, the value of eta is found to lie above the critical percolation threshold, while for 200 GeV d+Au collisions it is below the critical value. This supports the idea of string percolation, which at high enough string density is a possible mechanism to explore the hadronic phase transition to a quark-gluon plasma
Understanding the particle production mechanism with correlation studies using long and short range correlations
No full textLong range forward-backward multiplicity correlations have been measured with the STAR detector for Au+Au collisions at root(NN)-N-S = 200 GeV. Strong long range correlations are observed in central Au+Au collisions. Based on the Dual Parton model and Color Glass Condensate considerations the data suggests that these long range correlations are due to multiple parton interactions. This suggests that dense partonic matter is created in central Au+Au collisions at root(NN)-N-S = 200 GeV
The energy dependence of p(t) angular correlations inferred from mean-p(t) fluctuation scale dependence in heavy ion collisions at the SPS and RHIC
No full textWe present the first study of the energy dependence of pt angular correlations inferred from event-wisemean transversemomentum \u3c p(t)\u3e fluctuations in heavy ion collisions. We compare our large-acceptance measurements at CM energies root s(NN) = 19.6, 62.4, 130 and 200 GeV to SPS measurements at 12.3 and 17.3 GeV. p(t) angular correlation structure suggests that the principal source of pt correlations and fluctuations is minijets (minimum-bias parton fragments). We observe a dramatic increase in correlations and fluctuations from SPS to RHIC energies, increasing linearly with 1n root s(NN) from the onset of observable jet-related \u3c p(t)\u3e fluctuations near 10 GeV
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