27,095 research outputs found
Modeling of heavy-flavor pair correlations in Au-Au collisions at 200 A GeV at the BNL Relativistic Heavy Ion Collider
We study the nuclear modification of angular and momentum correlations
between heavy quark pairs in ultrarelativistic heavy-ion collisions. The
evolution of heavy quarks inside the thermalized medium is described via a
modified Langevin approach that incorporates both elastic and inelastic
interactions with the medium constituents. The spacetime evolution of the
fireball is obtained from a (2+1)-dimensional viscous hydrodynamics simulation.
The hadronization of heavy quarks is performed utilizing a hybrid model of
fragmentation and coalescence. Our results show that the nuclear modification
of the transverse momentum imbalance of D\bar{D} pairs reflects the total
energy loss experienced by the heavy quarks and may help us probe specific
regions of the medium. The angular correlation of heavy flavor pairs,
especially in the low to intermediate transverse momentum regime, is sensitive
to the detailed energy loss mechanism of heavy quarks inside the QGP.Comment: 10 pages, 9 figure
The ISM Interactions of a Runaway LBV Nebula in the LMC
New observations of the Magellanic Cloud Luminous Blue Variable candidate
S119 (HD269687) show the relationship of the star to its environs. Echelle
spectroscopy and high-resolution HST imagery reveal an expanding bubble
centered on the star. This bubble appears in both Halpha and [NII] and is
noticeably brighter on the near (blue-shifted) side. The systemic velocity of
both the expanding bubble and the star itself (as seen by the very broad Halpha
emission feature in the stellar spectrum) is V_hel=160 km/s whereas the
velocity of the superposed LMC ISM is 250-300 km/s. ISM absorption features
seen in FUSE spectra reveal components at both stellar and LMC velocities. Thus
we conclude that S119 is located within the LMC ISM and that the bubble is
interacting strongly with the ISM in a bow shock.Comment: 5 pages in EmulateApJ format, 3 figures Accepted by ApJL See
http://fuse.pha.jhu.edu/~danforth/s119
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