34,192 research outputs found
Light hadrons in 2+1 flavor lattice QCD
This talk will focus on recent results by the MILC collaboration from
simulations of light hadrons in 2+1 flavor lattice QCD. We have achieved high
precision results in the pseudoscalar sector, including masses and decay
constants, plus quark masses and Gasser-Leutwyler parameters from well
controlled chiral perturbation theory fits to our data. We also show
spectroscopy results for vector mesons and baryons.Comment: To appear in the proceedings of the First Meeting of the APS Topical
Group on Hadronic Physics, Fermilab, Batavia, Illinois, Oct. 24-26, 200
Jet-hadron correlations in STAR
Advancements in full jet reconstruction have made it possible to use jets as
triggers in azimuthal angular correlations to study the modification of
hard-scattered partons in the medium created in ultrarelativistic heavy-ion
collisions. This increases the range of parton energies accessible in these
analyses and improves the signal-to-background ratio compared to dihadron
correlations. Results of a systematic study of jet-hadron correlations in
central Au-Au collisions at sqrt(s_NN) = 200 GeV are indicative of a broadening
and softening of jets which interact with the medium. Furthermore, jet-hadron
correlations suggest that the suppression of the associated hadron yield at
high-pT is balanced in large part by low-pT enhancement.Comment: 4 pages, 2 figures, proceedings for Quark Matter 201
Determination of the chiral condensate from 2+1-flavor lattice QCD
We perform a precise calculation of the chiral condensate in QCD using
lattice QCD with 2+1 flavors of dynamical overlap quarks. Up and down quark
masses cover a range between 3 and 100 MeV on a 16^3x48 lattice at a lattice
spacing around 0.11 fm. At the lightest sea quark mass, the finite volume
system on the lattice is in the epsilon-regime. By matching the low-lying
eigenvalue spectrum of the Dirac operator with the prediction of chiral
perturbation theory at the next-to-leading order, we determine the chiral
condensate in 2+1-flavor QCD with strange quark mass fixed at its physical
value as Sigma (MS-bar at 2 GeV) = [242(04)(^+19_-18}) MeV}]^3, where the
errors are statistical and systematic, respectively.Comment: 4 pages, 3 figures, errors in table 1 and fig.3 corrected. Published
in PR
Star forming regions of the southern galaxy
A catalog of southern dust cloud properties is being compiled to aid in the planning and analysis of radio spectral line surveys in the southern hemisphere. Ultimately, images of dust temperature and column density will be produced. For the interim, a list of the 60 and 100 micron fluxes was prepared for the cores and adjacent backgrounds of 65 prominent dust clouds. Dust temperatures and column densities were derived
Fluctuation characteristics of the TCV snowflake divertor measured with high speed visible imaging
Tangentially viewing fast camera footage of the low-field side snowflake
minus divertor in TCV is analysed across a four point scan in which the
proximity of the two X-points is varied systematically. The motion of
structures observed in the post- processed movie shows two distinct regions of
the camera frame exhibiting differing patterns. One type of motion in the outer
scrape-off layer remains present throughout the scan whilst the other, apparent
in the inner scrape-off layer between the two nulls, becomes increasingly
significant as the X-points contract towards one another. The spatial structure
of the fluctuations in both regions is shown to conform to the equilibrium
magnetic field. When the X-point gap is wide the fluctuations measured in the
region between the X-points show a similar structure to the fluctuations
observed above the null region, remaining coherent for multiple toroidal turns
of the magnetic field and indicating a physical connectivity of the
fluctuations between the upstream and downstream regions. When the X-point gap
is small the fluctuations in the inner scrape-off layer between the nulls are
decorrelated from fluctuations upstream, indicating local production of
filamentary structures. The motion of filaments in the inter-null region
differs, with filaments showing a dominantly poloidal motion along magnetic
flux surfaces when the X-point gap is large, compared to a dominantly radial
motion across flux-surfaces when the gap is small. This demonstrates an
enhancement to cross-field tranport between the nulls of the TCV low-field-side
snowflake minus when the gap between the nulls is small.Comment: Accepted for publication in Plasma Physics and Controlled Fusio
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