The azimuthal anisotropy of electrons from heavy flavor decays in sqrt(s_NN) = 200 GeV Au-Au collisions by PHENIX

The transverse momentum dependence of the azimuthal anisotropy parameter v_{2}, the second harmonic of the azimuthal distribution, for electrons at mid-rapidity (|eta|<0.35) has been measured with the PHENIX detector in Au+Au collisions at sqrt(s_NN) = 200 GeV with respect to the reaction plane defined at high rapidities (|eta|=3-4). From the result we have calculated non-photonic electron v_{2}, which is expected to reflect the heavy-flavor azimuthal anisotropy, by subtracting v_{2} of electrons from other sources such as photon conversions, Dalitz decay etc.Comment: 4 pages, 4 figures, proceeding (poster) of the 18th International Conference on Nucleus-Nucleus Collisions (QM2005), Aug.4-9, Budapest, Hungar

Measurements of heavy-flavour decay leptons with ALICE

We present measurements of electrons and muons from heavy-flavour hadron decays at central and forward rapidity performed by the ALICE Collaboration in p–Pb (√sNN = 5.02 TeV) and Pb–Pb collisions (√sNN = 2.76 TeV). Electrons are reconstructed using several detectors of the ALICE central barrel. Muons are reconstructed using the muon spectrometer at forward rapidity (2.5 < y < 4). The nuclear modification factors in Pb–Pb (RAA) and in p–Pb (RpPb) collisions, and the azimuthal anisotropy (v2) in Pb– Pb collisions will be discussed. Theoretical predictions are compared with the data. In addition, the measurement of the azimuthal correlation between electrons from heavyflavour hadron decays and charged hadrons in p–Pb collisions will be shown

Measurement of RAA and v2 of electrons from heavy-flavour decays in Pb–Pb collisions at sNN=2.76 TeV with ALICE

AbstractWe present measurements of the nuclear modification factor (RAA) and azimuthal anisotropy (v2) of heavy-flavour decay electrons by the ALICE Collaboration at central rapidity in Pb–Pb collisions at sNN=2.76 TeV. A strong suppression of heavy-flavour decay electron production at high pT is observed in central Pb–Pb collisions, while non-zero v2 is seen at low pT in semi central collisions

Measurement of electron azimuthal anisotropy and implications of heavy quark flow in Au+Au collisions at [√sNN]=200 GeV

Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 4230, 2007.3.23Includes bibliographical reference

Formation of first star clusters under the supersonic gas flow -- I. Morphology of the massive metal-free gas cloud

We performed $42$ simulations of the first star formation with initial supersonic gas flows relative to the dark matter at the cosmic recombination era. Increasing the initial streaming velocities led to delayed halo formation and increased halo mass, enhancing the mass of the gravitationally shrinking gas cloud. For more massive gas clouds, the rate of temperature drop during contraction, in other words, the structure asymmetry, becomes more significant. When the maximum and minimum gas temperature ratios before and after contraction exceed about ten, the asymmetric structure of the gas cloud prevails, inducing fragmentation into multiple dense gas clouds. We continued our simulations until $10^5$ years after the first dense core formation to examine the final fate of the massive star-forming gas cloud. Among the $42$ models studied, we find the simultaneous formation of up to four dense gas clouds, with a total mass of about $2254\,M_\odot$. While the gas mass in the host halo increases with increasing the initial streaming velocity, the mass of the dense cores does not change significantly. The star formation efficiency decreases by more than one order of magnitude from $\epsilon_{\rm III} \sim 10^{-2}$ to $10^{-4}$ when the initial streaming velocity, normalised by the root mean square value, increases from 0 to 3.Comment: 15 pages, 16 figures, 1 table, Accepted for publication in MNRA