316,437 research outputs found
Non-perturbative renormalization of meson decay constants in quenched QCD for a renormalization group improved gauge action
Renormalization constants (-factors) of vector and axial-vector currents
are determined non-perturbatively in quenched QCD for a renormalization group
improved gauge action and a tadpole improved clover quark action using the
Schr\"odinger functional method. Non-perturbative values of -factors turn
out to be smaller than one-loop perturbative values by at lattice
spacing of 1 GeV. The pseudoscalar and vector meson decay
constants calculated with the non-perturbative -factors show a much better
scaling behavior compared to previous results obtained with tadpole improved
one-loop -factors. In particular, the non-perturbative -factors
normalized at infinite physical volume show that scaling violation of the decay
constants are within about 10% up to the lattice spacing GeV.
The continuum estimates obtained from data in the range 1 -- 2 GeV
agree with those determined from finer lattices ( GeV) with the
standard action.Comment: 19 pages, 18 eps figures. Corrected addres
Flavor Singlet Meson Mass in the Continuum Limit in Two-Flavor Lattice QCD
We present results for the mass of the eta-prime meson in the continuum limit
for two-flavor lattice QCD, calculated on the CP-PACS computer, using a
renormalization-group improved gauge action, and Sheikholeslami and Wohlert's
fermion action with tadpole-improved csw. Correlation functions are measured at
three values of the coupling constant beta corresponding to the lattice spacing
a approx. 0.22, 0.16, 0.11 fm and for four values of the quark mass parameter
kappa corresponding to mpi over mrho approx. 0.8, 0.75, 0.7 and 0.6. For each
beta, kappa pair, 400-800 gauge configurations are used. The two-loop diagrams
are evaluated using a noisy source method. We calculate eta-prime propagators
using local sources, and find that excited state contributions are much reduced
by smearing. A full analysis for the smeared propagators gives
metaprime=0.960(87)+0.036-0.248 GeV, in the continuum limit, where the second
error represents the systematic uncertainty coming from varying the functional
form for chiral and continuum extrapolations.Comment: 9 pages, 19 figures, 4 table
B meson leptonic decay constant with quenched lattice NRQCD
We present a lattice NRQCD study of the B meson decay constant in the
quenched approximation with emphasis given to the scaling behavior. The NRQCD
action and the heavy-light axial current we use include all terms of order 1/M
and the perturbative and corrections. Using
simulations at three value of couplings =5.7, 5.9 and 6.1 on lattices of
size and , we find no significant
dependence in if the correction is included in the
axial current. We obtain MeV, MeV and , with the
first error being statistical, the second systematic, and the third due to
uncertainty of strange quark mass, while quenching errors being not included.Comment: 31 pages, 24 eps figure
Kaon B parameter from quenched Lattice QCD
We present results of a large-scale simulation for the Kaon B parameter
in quenched lattice QCD with the Kogut-Susskind quark action. Calculating
at 1% statistical accuracy for seven values of lattice spacing in the range
fm on lattices up to , we verify a
quadratic dependence of theoretically predicted. Strong indications
are found that, with our level of accuracy, terms
arising from our one-loop matching procedure have to be included in the
continuum extrapolation. We present (NDR, 2 GeV)=0.628(42) as our final
value, as obtained by a fit including the term.Comment: 8 pages, Latex(revtex, epsf), 2 epsf figure
Light quark masses from unquenched lattice QCD
We calculate the light meson spectrum and the light quark masses by lattice
QCD simulation, treating all light quarks dynamically and employing the Iwasaki
gluon action and the nonperturbatively O(a)-improved Wilson quark action. The
calculations are made at the squared lattice spacings at an equal distance
a^2~0.005, 0.01 and 0.015 fm^2, and the continuum limit is taken assuming an
O(a^2) discretization error. The light meson spectrum is consistent with
experiment. The up, down and strange quark masses in the \bar{MS} scheme at 2
GeV are \bar{m}=(m_{u}+m_{d})/2=3.55^{+0.65}_{-0.28} MeV and
m_s=90.1^{+17.2}_{-6.1} MeV where the error includes statistical and all
systematic errors added in quadrature. These values contain the previous
estimates obtained with the dynamical u and d quarks within the error.Comment: 4 pages, 3 figures, revtex4; v2: contents partly modified, published
versio
Lattice QCD calculation of the proton decay matrix element in the continuum limit
We present a quenched lattice QCD calculation of the \alpha and \beta
parameters of the proton decay matrix element. The simulation is carried out
using the Wilson quark action at three values of the lattice spacing in the
range a\approx 0.1-0.064 fm to study the scaling violation effect. We find only
mild scaling violation when the lattice scale is determined by the nucleon
mass. We obtain in the continuum limit,
|\alpha(NDR,2GeV)|=0.0090(09)(^{+5}_{-19})GeV^3 and
|\beta(NDR,2GeV)|=0.0096(09)(^{+6}_{-20})GeV^3 with \alpha and \beta in a
relatively opposite sign, where the first error is statistical and the second
is due to the uncertainty in the determination of the physical scale.Comment: 4 pages, 3 figure
B meson B-parameters and the decay constant in two-flavor dynamical QCD
We present a two-flavor dynamical QCD calculation of the B meson B parameters
and decay constant. We use NRQCD for heavy quark and the nonperturbatively
O(a)-improved Wilson action for light quark at =5.2 on a
lattice. We confirm that the sea quark effect increases the heavy-light decay
constant, while estimate of its magnitude depends significantly on the fitting
form in the chiral extrapolation. For the B parameters, on the other hand, we
do not find a significant sea quark effect. The chiral extrapolation with
logarithmic term is examined for both quantities and compared with the
prediction of ChPT.Comment: 3 pages, 3 figures, Lattice2001(heavyquark
Decreasing Caregiver Stress
Stress is both critical and personal experience and has significant effects on caregivers’ physical, mental, and social well-being. The nature of caregiving and the responsibility to work and serve individuals at their illness conditions are very personal encounters that often result in adverse effects on the health and well-being of caregivers (Frederick, 2016). A decrease in stress experience can lead to the satisfaction of caregiver roles and improvement of patient’s quality of life (Choi, Jisun & Boyle, Diane, 2013; Yada, Nagata, & Inagaki, 2014). This scholarly project determined that evidence-based stress management interventions have decreased the perceived stress in caregivers. The scholarly project identified low levels of stress among research participants, and how evidence-based interventions decreased caregiver stress by increasing their knowledge and awareness of evidence-based stress management interventions. The results of this scholarly project agree with the literature that caregiver stress experience can be decreased through the implementation of evidence-based stress management interventions (Blom, Zarit, Groot Zwaaftink, Cuijpers, & Pot, 2013). It is significant to implement evidence-based stress management interventions to decrease perceived stress among caregivers
- …