43 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
The equation of state in lattice QCD: with physical quark masses towards the continuum limit
The equation of state of QCD at vanishing chemical potential as a function of
temperature is determined for two sets of lattice spacings. Coarser lattices
with temporal extension of N_t=4 and finer lattices of N_t=6 are used. Symanzik
improved gauge and stout-link improved staggered fermionic actions are applied.
The results are given for physical quark masses both for the light quarks and
for the strange quark. Pressure, energy density, entropy density, quark number
susceptibilities and the speed of sound are presented.Comment: 14 pages, 9 figures. Version published in JHEP: discussions added in
Sects. 1, 2. Fig. 1 changed and a new figure for the interaction measure
added. Information on statistics added in Table 1. Raw values of the pressure
added in Table 3. A few references adde
Heavy-Light Decay Constants: Conclusions from the Wilson Action
We report on the results of a MILC collaboration calculation of ,
, , and their ratios. We discuss the most important
errors in more detail than we have elsewhere.Comment: LATTICE98(heavyqk) 3 latex pages and 3 postscript figures. The
perturbative correction calculated by Kuramashi has been adjusted to take
into account the fact that we match to the continuum at the kinetic mass of
the heavy meson, not the pole mass. This produces a 2 to 4 MeV change in
final results for decay constants, and has negligible effect on decay
constant ratio
Update on the physics of light pseudoscalar mesons
We present an update of the MILC investigation of the properties of light
pseudoscalar mesons using three flavors of improved staggered quarks. Results
are presented for the and leptonic decay constants, the CKM matrix
element , the up, down and strange quark masses, and the coefficients
of the chiral lagrangian. We have new data for lattice spacing fm with several values of the light quark mass down to one-tenth
the strange quark mass, higher statistics for fm with the
light quark mass equal to one-tenth the strange quark mass, and initial results
for our smallest lattice spacing, fm with light quark mass
two-fifths of the strange quark mass.Comment: 7 pages, 4 figures. To be published in Proceedings of Science
(Lattice 2006) 163 (2006
The Phase Diagram of High Temperature QCD with Three Flavors of Improved Staggered Quarks
We report on progress in our study of high temperature QCD with three flavors
of improved staggered quarks. Simulations are being carried out with three
degenerate quarks with masses less than or equal to the strange quark mass,
, and with degenerate up and down quarks with masses in the range , and the strange quark mass fixed near its physical
value. For the quark masses studied to date we find rapid crossovers, which
sharpen as the quark mass is reduced, rather than bona fide phase transitions.Comment: Lattice 2003 (Nonzero temperature and density
Update on pi and K Physics
We present an update of the MILC studies of the physics of light
pseudoscalars using improved staggered fermions. New runs at lighter quark
mass, as well as increased statistics for older sets, are enabling us to
improve the results for decay constants in full QCD. In addition, we have
analyzed quenched runs at two different lattice spacings. This makes possible a
test of the applicability of staggered chiral perturbation theory in a
different context.Comment: presented at Lattice2005(Hadron Spectrum), Dublin, July 25-30, 2005,
6 pages, 4 figures, to appear in Proceedings of Scienc
B Mixing in the Standard Model and Beyond: Lattice QCD
We give a brief overview and progress report on our lattice QCD calculation
of neutral B mixing hadronic matrix elements needed for Standard Model and
Beyond the Standard Model physics. Reference [1] contains more details and
results.Comment: 3 pages, 0 figures, Proceedings of the 19th Particles and Nuclei
International Conference (PANIC11), Cambridge, MA, U.S.A., July 201
The scaling dimension of low lying Dirac eigenmodes and of the topological charge density
As a quantitative measure of localization, the inverse participation ratio of
low lying Dirac eigenmodes and topological charge density is calculated on
quenched lattices over a wide range of lattice spacings and volumes. Since
different topological objects (instantons, vortices, monopoles, and artifacts)
have different co-dimension, scaling analysis provides information on the
amount of each present and their correlation with the localization of low lying
eigenmodes.Comment: Lattice2004(topology), Fermilab, June 21 - 26, 2004; 3 pages, 3
figure
QCD equation of state at non-zero chemical potential
We present our new results for the QCD equation of state at nonzero chemical
potential at N_t=6 and compare them with N_t=4. We use the Taylor expansion
method with terms up to sixth order in simulations with 2+1 flavors of improved
asqtad quarks along a line of constant physics with m_l=0.1 m_s and
approximately physical strange quark mass m_s.Comment: 7 pages, 10 figures, presented at Lattice 2008 (Nonzero Temperature
and Density), College of William and Mary, Williamsburg, V