514 research outputs found
Is the ice bath finally melting? CWI is no greater than active recovery upon local and systemic inflammatory cellular stress in humans.
Over the past decade, significant research has focussed on optimising the recovery of elite athletes. The premise behind such a theory is that sub-optimal recovery often leads to fatigue, reducing the quality of subsequent training sessions and/or competitive performances, whilst potentially hindering adaptive processes. There is now a plethora of research focussing on the impact of one such recovery strategy, cold-water immersion (CWI), and the benefits it may provide post-exercise
The Kaon B-parameter from Quenched Domain-Wall QCD
We present numerical results for the kaon B-parameter, B_K, determined in the
quenched approximation of lattice QCD. Our simulations are performed using
domain-wall fermions and the renormalization group improved, DBW2 gauge action
which combine to give quarks with good chiral symmetry at finite lattice
spacing. Operators are renormalized non-perturbatively using the RI/MOM scheme.
We study scaling by performing the simulation on two different lattices with
a^{-1} = 1.982(30) and 2.914(54) GeV. We combine this quenched scaling study
with an earlier calculation of B_K using two flavors of dynamical, domain-wall
quarks at a single lattice spacing to obtain
B_K(MS,NDR,mu=2GeV)=0.563(21)(39)(30), were the first error is statistical, the
second systematic (without quenching errors) and the third estimates the error
due to quenching.Comment: 77 pages, 44 figures, to be published in Phys. Rev.
Enhanced chiral logarithms in partially quenched QCD
I discuss the properties of pions in ``partially quenched'' theories, i.e.
those in which the valence and sea quark masses, and , are
different. I point out that for lattice fermions which retain some chiral
symmetry on the lattice, e.g. staggered fermions, the leading order prediction
of the chiral expansion is that the mass of the pion depends only on , and
is independent of . This surprising result is shown to receive corrections
from loop effects which are of relative size , and which thus
diverge when the valence quark mass vanishes. Using partially quenched chiral
perturbation theory, I calculate the full one-loop correction to the mass and
decay constant of pions composed of two non-degenerate quarks, and suggest
various combinations for which the prediction is independent of the unknown
coefficients of the analytic terms in the chiral Lagrangian. These results can
also be tested with Wilson fermions if one uses a non-perturbative definition
of the quark mass.Comment: 14 pages, 3 figures, uses psfig. Typos in eqs (18)-(20) corrected
(alpha_4 is replaced by alpha_4/2
Scaling of Pseudo-Critical Couplings in Two-Flavour QCD
We study the scaling behaviour of the pseudo-critical couplings for the
chiral phase transition in two-flavour QCD. We show that all existing results
from lattice simulations on lattices with temporal extent , 6 and 8
can be mapped onto a universal scaling curve. The relevant combination of
critical exponents, , is consistent with the scaling behaviour
expected for a second order phase transition with exponents. At present,
scaling according to the symmetry group can, however, not be ruled out.Comment: 8 pages, NSF-ITP 93-12
The finite temperature QCD using 2+1 flavors of domain wall fermions at N_t = 8
We study the region of the QCD phase transition using 2+1 flavors of domain
wall fermions (DWF) and a lattice volume with a fifth dimension
of . The disconnected light quark chiral susceptibility, quark number
susceptibility and the Polyakov loop suggest a chiral and deconfining crossover
transition lying between 155 and 185 MeV for our choice of quark mass and
lattice spacing. In this region the lattice scale deduced from the Sommer
parameter is GeV, the pion mass is MeV
and the kaon mass is approximately physical. The peak in the chiral
susceptibility implies a pseudo critical temperature MeV
where the first error is associated with determining the peak location and the
second with our unphysical light quark mass and non-zero lattice spacing. The
effects of residual chiral symmetry breaking on the chiral condensate and
disconnected chiral susceptibility are studied using several values of the
valence .Comment: 41 pages, 10 tables, 13 figure
Testing Algorithms for Finite Temperature Lattice QCD
We discuss recent algorithmic improvements in simulating finite temperature
QCD on a lattice. In particular, the Rational Hybrid Monte Carlo(RHMC)
algorithm is employed to generate lattice configurations for 2+1 flavor QCD.
Unlike the Hybrid R Algorithm, RHMC is reversible, admitting a Metropolis
accept/reject step that eliminates the errors
inherent in the R Algorithm. We also employ several algorithmic speed-ups,
including multiple time scales, the use of a more efficient numerical
integrator, and Hasenbusch pre-conditioning of the fermion force.Comment: 4 pages, 2 figures, poster presented at International Conference on
Strong and Electroweak Matter 2006 (SEWM2006), BNL, May 10-13, 200
Z Boson Propagator Correction in Technicolor Theories with ETC Effects Included
We calculate the Z boson propagator correction, as described by the S
parameter, in technicolor theories with extended technicolor interactions
included. Our method is to solve the Bethe-Salpeter equation for the requisite
current-current correlation functions. Our results suggest that the inclusion
of extended technicolor interactions has a relatively small effect on S.Comment: 15pages, 8 figure
Dynamical QCD thermodynamics with domain wall fermions
We present results from numerical simulations of full, two flavor QCD
thermodynamics at N_t=4 with domain wall fermions. For the first time a
numerical simulation of the full QCD phase transition displays a low
temperature phase with spontaneous chiral symmetry breaking but intact flavor
symmetry and a high temperature phase with the full SU(2) x SU(2) chiral flavor
symmetry.Comment: LATTICE98(hightemp
Quenched QCD with domain wall fermions
We report on simulations of quenched QCD using domain wall fermions, where we
focus on basic questions about the formalism and its ability to produce
expected low energy hadronic physics for light quarks. The work reported here
is on quenched lattices at and 5.85, using values
for the length of the fifth dimension between 10 and 48. We report results for
parameter choices which lead to the desired number of flavors, a study of
undamped modes in the extra dimension and hadron masses.Comment: Contribution to Lattice '98. Presented by R. Mawhinney. 3 pages, 3
figure
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