619 research outputs found

    Particle production in matter at extreme conditions

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    We study particle production and its density evolution and equilibration in hot dense medium. One type of hot dense medium, which we study, is hadronic gas produced at quark gluon plasma hadronization in heavy ions collisions in SPS, RHIC and LHC experiments. We study hadron production at non-equilibrium quark gluon plasma hadronization and their evolution in thermal hadronic gas phase. We use non-equilibrium hadronization as the initial condition in the study of hadronic kinetic phase. During this time period some hadronic resonances can be produced in lighter hadrons fusion. Production of resonances is dominant over decay if there is non-equilibrium excess of decay products. Within this model we explain apparently contradictory experimental results reported in RHIC experiments: Sigma(1385) yield is enhanced while Lambda(1520) yield is suppressed compared to the statistical hadronization model expectation obtained without kinetic phase. We also predict Delta(1232) enhancement. The second type of plasma medium we consider is the relativistic electron positron photon plasma drop. This plasma is expected to be produced in decay of supercritical field created in ultrashort laser pulse. We study at what conditions this plasma drop is opaque for photons and therefore may reach thermal and chemical equilibrium. Further we consider muon and pion production in this plasma also as a diagnostic tool. Finally all these theoretical developments can be applied to begin a study of particles evolution in early universe in temperatures domain from QGP hadronization (160 MeV) to nucleosynthesis (0.1 MeV). The first results on pion equilibration are presented here.Comment: PhD dissertation, as accepted by the University of Arizona, 197 page

    Charmed Hadrons from Strangeness-rich QGP

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    The yields of charmed hadrons emitted by strangeness rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.Comment: 6 pages, 2 figures SQM 2006; the same as J. Phys. G in pres

    Enhanced Production of Delta(1230) and Sigma(1385) Resonances

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    Yields of Delta(1230), Sigma(1385) resonances produced in heavy ion collisions are studied within the framework of a kinetic master equation. The time evolution is driven by the process Delta(1230) \leftrightarrow N \pi, Sigma(1385) \leftrightarrow \Lambda \pi . We obtain resonance yield both below and above chemical equilibrium, depending on initial hadronization condition and separation of kinetic and chemical freeze-out.Comment: 6 pages, 3 figure

    Unstable Hadrons in Hot Hadron Gas in Laboratory and in the Early Universe

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    We study kinetic master equations for chemical reactions involving the formation and the natural decay of unstable particles in a thermal bath. We consider the decay channel of one into two particles, and the inverse process, fusion of two thermal particles into one. We present the master equations the evolution of the density of the unstable particles in the early Universe. We obtain the thermal invariant reaction rate using as an input the free space (vacuum) decay time and show the medium quantum effects on π+πρ\pi+\pi \leftrightarrow \rho reaction relaxation time. As another laboratory example we describe the K+KϕK+K \leftrightarrow \phi process in thermal hadronic gas in heavy-ion collisions. A particularly interesting application of our formalism is the π0γ+γ\pi^{0}\leftrightarrow \gamma +\gamma process in the early Universe. We also explore the physics of π±\pi^{\pm} and μ±\mu^{\pm} freeze-out in the Universe.Comment: 13 pages, 9 figures, published in Physical Review

    Pion and muon production in electron-positron photon plasma

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    We study production and equilibration of pions and muons in relativistic electron-positron-photon plasma at a temperature Tmμ,mπT\ll m_\mu, m_\pi . We argue that the observation of pions and muons can be a diagnostic tool in the study of the initial properties of such a plasma formed by means of strong laser fields. Conversely, properties of muons and pions in thermal environment become accessible to precise experimental study.Comment: 16 pages, v3 imporved presentation in response to PRD review, v4 minor corrections presumably the "to be" published versio

    Efficacy and safety of the use of alirocumab in real clinical practice

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    Aim. To evaluate the results of two-year use of alirokumab in Karelia Republic. Materials and methods. The observation group consisted of 27 patients (17 patients with familial hypercholesterolemia, 10 patients with the history of myocardial infarction), mean age 53.44.3 years, 70.3% men, follow-up duration from one year to 2.5 years, 18 (66.6%) patients received therapy for more than 2 years. 19 patients received alirocumab at a dose of 75 mg/ml once every 2 weeks, eight at a dose of 150 mg/ml once every 2 weeks. Before the start of therapy, the majority received maximally tolerated statin therapy, 10 patients received statin therapy in combination with ezetemibe, 3 patients received ezetemibe monotherapy due to statin intolerance. The target levels of LDL cholesterol were considered for very high risk patients less than 1.4 mmol/L, high risk less than 1.8 mmol/L, extreme risk less than 1 mmol/L. Results. The reduction of LDL on therapy with alirocumab was 58%; target levels of LDL were achieved in 77.8%. The level of decrease in LDL cholesterol less than 50% was noted only in 7.4% of cases. Patients requiring a large dose of the drug were classified as very high risk, had higher cholesterol and LDL-C levels. The level of Lp(a) decrease on 29.7% by 612 months. No destabilization of coronary heart disease, new cases of stroke were registered. Conclusion. The inclusion of alirocumab in the treatment regimen contributed to the stable course of atherosclerosis-associated diseases, the achievement of LDL cholesterol targets in 77.8% of patients, was not accompanied by side effects during 2.5 years therapy

    Strangeness and threshold of phase changes

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    We explore entropy and strangeness as signature of QGP for top AGS energy and the energy scan at SPS. We find that the hadronization dynamics changes between 20 and 30 AA GeV projectile energy. The high energy results are consistent with QGP.Comment: Presented at SQM07, to appear in JPG special issu

    Association of genetic variation with systolic and diastolic blood pressure among African Americans: the Candidate Gene Association Resource study

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    The prevalence of hypertension in African Americans (AAs) is higher than in other US groups; yet, few have performed genome-wide association studies (GWASs) in AA. Among people of European descent, GWASs have identified genetic variants at 13 loci that are associated with blood pressure. It is unknown if these variants confer susceptibility in people of African ancestry. Here, we examined genome-wide and candidate gene associations with systolic blood pressure (SBP) and diastolic blood pressure (DBP) using the Candidate Gene Association Resource (CARe) consortium consisting of 8591 AAs. Genotypes included genome-wide single-nucleotide polymorphism (SNP) data utilizing the Affymetrix 6.0 array with imputation to 2.5 million HapMap SNPs and candidate gene SNP data utilizing a 50K cardiovascular gene-centric array (ITMAT-Broad-CARe [IBC] array). For Affymetrix data, the strongest signal for DBP was rs10474346 (P= 3.6 × 10−8) located near GPR98 and ARRDC3. For SBP, the strongest signal was rs2258119 in C21orf91 (P= 4.7 × 10−8). The top IBC association for SBP was rs2012318 (P= 6.4 × 10−6) near SLC25A42 and for DBP was rs2523586 (P= 1.3 × 10−6) near HLA-B. None of the top variants replicated in additional AA (n = 11 882) or European-American (n = 69 899) cohorts. We replicated previously reported European-American blood pressure SNPs in our AA samples (SH2B3, P= 0.009; TBX3-TBX5, P= 0.03; and CSK-ULK3, P= 0.0004). These genetic loci represent the best evidence of genetic influences on SBP and DBP in AAs to date. More broadly, this work supports that notion that blood pressure among AAs is a trait with genetic underpinnings but also with significant complexit
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