Nuclear Reactions Rates Governing the Nucleosynthesis of Ti44

Large excesses of Ca44 in certain presolar graphite and silicon carbide grains give strong evidence for Ti44 production in supernovae. Furthermore, recent detection of the Ti44 gamma-line from the Cas A SNR by CGRO/COMPTEL shows that radioactive Ti44 is produced in supernovae. These make the Ti44 abundance an observable diagnostic of supernovae. Through use of a nuclear reaction network, we have systematically varied reaction rates and groups of reaction rates to experimentally identify those that govern Ti44 abundance in core-collapse supernova nucleosynthesis. We survey the nuclear-rate dependence by repeated calculations of the identical adiabatic expansion, with peak temperature and density chosen to be 5.5xE9 K and 1E7 g/cc, respectively, to approximate the conditions in detailed supernova models. We find that, for equal total numbers of neutrons and protons (eta=0), Ti44 production is most sensitive to the following reaction rates: Ti44(alpha,p)V47, alpha(2alpha,gamma)C12, Ti44(alpha,gamma)Cr48, V45(p,gamma)Cr46. We tabulate the most sensitive reactions in order of their importance to the Ti44 production near the standard values of currently accepted cross-sections, at both reduced reaction rate (0.01X) and at increased reaction rate (100X) relative to their standard values. Although most reactions retain their importance for eta > 0, that of V45(p,gamma)Cr46 drops rapidly for eta >= 0.0004. Other reactions assume greater significance at greater neutron excess: C12(alpha,gamma)O16, Ca40(alpha,gamma)Ti44, Al27(alpha,n)P30, Si30(alpha,n)S33. Because many of these rates are unknown experimentally, our results suggest the most important targets for future cross section measurements governing the value of this observable abundance.Comment: 37 pages, LaTex, 17 figures, 8 table

Medium information from anisotropic flow and jet quenching in relativistic heavy ion collisions

Within a multiphase transport (AMPT) model, where the initial conditions are obtained from the recently updated HIJING 2.0 model, the recent anisotropic flow and suppression data for charged hadrons in Pb+Pb collisions at the LHC center of mass energy of 2.76 TeV are explored to constrain the properties of the partonic medium formed. In contrast to RHIC, the measured centrality dependence of charged hadron multiplicity dN_ch/deta at LHC provides severe constraint to the largely uncertain gluon shadowing parameter s_g. We find final-state parton scatterings reduce considerably hadron yield at midrapidity and enforces a smaller s_g to be consistent with dN_ch/deta data at LHC. With the parton shadowing so constrained, hadron production and flow over a wide transverse momenta range are investigated in AMPT. The model calculations for the elliptic and triangular flow are found to be in excellent agreement with the RHIC data, and predictions for the flow coefficients v_n(p_T, cent) at LHC are given. The magnitude and pattern of suppression of the hadrons in AMPT are found consistent with the measurements at RHIC. However, the suppression is distinctly overpredicted in Pb+Pb collisions at the LHC energy. Reduction of the QCD coupling constant alpha_s by ~30% in the higher temperature plasma formed at LHC reproduces the measured hadron suppression.Comment: Talk given by Subrata Pal at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

Elliptic flow fluctuations in 200 GeV Au+Au collisions at RHIC

We present first results on event-by-event elliptic flow fluctuations in Au+Au collisions at 200 GeV obtained with the PHOBOS detector. Over the measured range in centrality, large relative fluctuations of 40--50% are found. The elliptic flow fluctuations are well described as being proportional to fluctuations in the shape of the initial collision region, as estimated event-by-event with the participant eccentricity using Glauber Monte Carlo.Comment: 5 pages, 2 figures, QM 2006 proceedings; v2: Corrected a few typo

Equation of State for Exclusion Statistics in a Harmonic Well

We consider the equations of state for systems of particles with exclusion statistics in a harmonic well. Paradygmatic examples are noninteracting particles obeying ideal fractional exclusion statistics placed in (i) a harmonic well on a line, and (ii) a harmonic well in the Lowest Landau Level (LLL) of an exterior magnetic field. We show their identity with (i) the Calogero model and (ii) anyons in the LLL of an exterior magnetic field and in a harmonic well.Comment: latex file, 11 page

Diagnosing Energy Loss: PHENIX Results on High-pT Hadron Spectra

Measurements of inclusive spectra of hadrons at large transverse momentum over a broad range of energy in different collision systems have been performed with the PHENIX experiment at RHIC. The data allow to study the energy and system size dependence of the suppression observed in RAA of high-pT hadrons at sqrt(s_NN)= 200 GeV. Due to the large energy range from sqrt(s_NN)= 22 GeV to 200 GeV, the results can be compared to results from CERN SPS at a similar energy. The large Au+Au dataset from the 2004 run of RHIC also allows to constrain theoretical models that describe the hot and dense matter produced in such collisions. Investigation of particle ratios such as eta/pi0 helps understanding the mechanisms of energy loss.Comment: 4 pages, 6 figures. To appear in the proceedings of the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2006), Shanghai, China, November 14-20, 200

Descriptive Analysis of Assaults in Domestic Violence Incidents Reported to Alaska State Troopers: 2004

This project examined the characteristics of assaults in domestic violence incidents reported to the Alaska State Troopers. Assaults are only one type of criminal offense defined in Alaska statutes as a crime involving domestic violence. This report is not inclusive of all crimes involving domestic violence reported to AST, because it only includes assaults. In addition, this report is not inclusive of assaults in domestic violence incidents that were reported to municipal police departments across Alaska. Only assaults in domestic violence incidents reported to AST are described in this report. The term assault will be used throughout this report to define assault cases that are crimes involving domestic violence incidents; this includes felony and misdemeanor assaults. The sample utilized for this analysis included all assaults in domestic violence incidents reported to AST in 2004. It included information from 1,281 reports on 1,803 assault charges, 1,356 suspects, 1,523 victims, and 1,283 witnesses. This descriptive analysis documents the characteristics of these reports, charges, suspects, victims, witnesses, and legal resolutions.Index of Tables and Figures / Acknowledgements / Executive Summary / Descriptive Analysis of Assaults in Domestic Violence Incidents / Brief Overview of the State of Alaska / Brief Overview of the Alaska State Troopers / Summary of Alaska's Criminal Assault Statutes / Purpose of this Study / Methods / Report Characteristics / Suspect Characteristics / Victim Characteristics / Incident Characteristics / Witness Characteristics / Legal Resolutions / Appendix A -- Data Collection Instruments / Appendix B -- 2004 Alaska's Criminal Assault Statute