4,123 research outputs found
Hybrid configuration content of heavy S-wave mesons
We use the non-relativistic expansion of QCD (NRQCD) on the lattice to study
the lowest hybrid configuration contribution to the ground state of heavy
S-wave mesons. Using lowest-order lattice NRQCD to create the heavy-quark
propagators, we form a basis of ``unperturbed'' S-wave and hybrid states. We
then apply the lowest-order coupling of the quark spin and chromomagnetic field
at an intermediate time slice to create ``mixed'' correlators between the
S-wave and hybrid states. From the resulting amplitudes, we extract the
off-diagonal element of our two-state Hamiltonian. Diagonalizing this
Hamiltonian gives us the admixture of hybrid configuration within the meson
ground state. The present effort represents a continuation of previous work:
the analysis has been extended to include lattices of varying spacings, source
operators having better overlap with the ground states, and the pseudoscalar
(along with the vector) channel. Results are presented for bottomonium
(, ) using three different sets of quenched lattices. We
also show results for charmonium (, ) from one lattice set,
although we note that the non-relativistic approximation is not expected to be
very good in this case.Comment: 9 pages, 7 figures, version to appear in Phys Rev
Hadron Spectroscopy with Dynamical Chirally Improved Fermions
We simulate two dynamical, mass degenerate light quarks on 16^3x32 lattices
with a spatial extent of 2.4 fm using the Chirally Improved Dirac operator. The
simulation method, the implementation of the action and signals of
equilibration are discussed in detail. Based on the eigenvalues of the Dirac
operator we discuss some qualitative features of our approach. Results for
ground state masses of pseudoscalar and vector mesons as well as for the
nucleon and delta baryons are presented.Comment: 26 pages, 17 figures, 10 table
The equation of state with nonzero chemical potential for 2+1 flavors
We present results for the QCD equation of state with nonzero chemical
potential using the Taylor expansion method with terms up to sixth order in the
expansion. Our calculations are performed on asqtad 2+1 quark flavor lattices
at .Comment: Talk given at the XXV International Symposium on Lattice Field
Theory, July 30-4 August 2007, Regensburg, German
AN IMPROVED ESTIMATOR FOR ASSESSING THE MEASURE OF AGREEMENT WITH A GOLD STANDARD
St. Laurent (1998, Biometrics 54, 537-545) developed a measure of agreement for method comparison studies in which an approximate method of measurement is compared to a gold standard method of measurement. The measure of agreement proposed was shown to be related to a population intraclass correlation coefficient. This paper develops a family of estimators for the measure of agreement based on pivotal quantities. A blend of two particular members of the family is suggested as an estimator itself. In general, this estimator outperforms the maximum likelihood estimator in terms of bias and mean-squared error
The QCD equation of state with asqtad staggered fermions
We report on our result for the equation of state (EOS) with a Symanzik
improved gauge action and the asqtad improved staggered fermion action at
and 6. In our dynamical simulations with 2+1 flavors we use the inexact
R algorithm and here we estimate the finite step-size systematic error on the
EOS. Finally we discuss the non-zero chemical potential extension of the EOS
and give some preliminary results.Comment: 7 pages, 6 figures, presented at Lattice2006(High Temperature and
Density), to appear in Proceedings of Scienc
If you leave, don\u27t leave now: The role of gender, sociosexuality, and fear of being single on desire to engage in breakup sex
Experiencing a romantic breakup is often a complicated and emotional experience, and in many cases, this emotional ambivalence leads to people having âbreakup sexâ with their ex-partners. To better understand this complicated relationship stage, we sampled 987 single adults to understand how individual differences in sociosexuality and fear of being single predict one\u27s desire to have breakup sex and previous breakup sex experience. We observed that both men and women who reported more unrestricted sociosexual orientations reported greater desire for breakup sex. However, womenâbut not menâwho reported greater fear of being single reported a greater desire for breakup sex. Lastly, those who reported a more unrestricted sociosexual orientation were more likely to have had breakup sex in the past. Results suggest that both men\u27s and women\u27s desire for casual sex impacts engagement in breakup sex and that women\u27s desire is also motivated by their fear of being single
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