11,939 research outputs found
SU(2) gluon propagator on a coarse anisotropic lattice
We calculated the SU(2) gluon propagator in Landau gauge on an anisotropic
coarse lattice with the improved action. The standard and the improved scheme
are used to fix the gauge in this work. Even on the coarse lattice the lattice
gluon propagator can be well described by a function of the continuous
momentum. The effect of the improved gauge fixing scheme is found not to be
apparent. Based on the Marenzoni's model, the mass scale and the anomalous
dimension are extracted and can be reasonably extrapolated to the continuum
limit with the values and . We also extract the
physical anisotropy from the gluon propagator due to the explicit
dependence of the gluon propagator.Comment: LaTeX, 14 pages including 4 ps figure
On Two-Body Decays of A Scalar Glueball
We study two body decays of a scalar glueball. We show that in QCD a spin-0
pure glueball (a state only with gluons) cannot decay into a pair of light
quarks if chiral symmetry holds exactly, i.e., the decay amplitude is chirally
suppressed. However, this chiral suppression does not materialize itself at the
hadron level such as in decays into and , because in
perturbative QCD the glueball couples to two (but not one) light quark pairs
that hadronize to two mesons. Using QCD factorization based on an effective
Lagrangian, we show that the difference of hadronization into and
already leads to a large difference between and , even the decay amplitude is not chirally suppressed. Moreover,
the small ratio of of
measured in experiment does not imply to be a pure glueball. With
our results it is helpful to understand the partonic contents if or is measured reliably.Comment: revised versio
Local spin fluctuations in iron-based superconductors: 77Se and 87Rb NMR measurements of Tl0.47Rb0.34Fe1.63Se2
We report nuclear magnetic resonance (NMR) studies of the intercalated iron
selenide superconductor (Tl, Rb)FeSe ( K).
Single-crystal measurements up to 480 K on both Se and Rb nuclei
show a superconducting phase with no magnetic order. The Knight shifts and
relaxation rates increase very strongly with temperature above ,
before flattening at 400 K. The quadratic -dependence and perfect
proportionality of both and data demonstrate their origin in
paramagnetic moments. A minimal model for this pseudogap-like response is not a
missing density of states but two additive contributions from the itinerant
electronic and local magnetic components, a framework unifying the and
data in many iron-based superconductors
MC-Simulation of the Transverse Double Spin Asymmetry for RHIC
Using {\sc Sphinx tt}, a new MC simulation program for transverse polarized
nucleon--nucleon scattering based on {\sc Pythia~5.6}, we calculate the
transverse double spin asymmetry in the Drell-Yan process. If one
assumes (quite arbitrarily) that the transversity parton distribution equals the helicity distribution at some low
scale, the resulting asymmetry is of order 1\%. In this case is
would hardly be be measurable with PHENIX at RHIC.Comment: 17 pages, 5 figure
Three-photon absorption in water-soluble ZnS nanocrystals
We report on large three-photon absorption (3PA) in glutathione-capped ZnS
semiconductor nanocrystals (NCs), determined by both Z-scan and transient
transmission techniques with 120-fs laser pulses. The monodispersed,
water-soluble ZnS NCs are synthesized by a modified protocol with a mean
diameter of 2.5 nm. Their 3PA cross-section is determined to be around
2.7x10^-78 cm^6s^2photon^-2 at an optimal wavelength of commercial Ti:sapphire
femtosecond lasers. This value is nearly one order of magnitude greater than
that of CdS NCs, and four to five orders of magnitude higher than those of the
previously reported common UV fluorescent dyes.Comment: 15 pages, 4 figure
Lifting method to analyze pipeline deformation
Lifting is to use lifting equipment to lift components and install them to the designated position. On the main structure, lifting equipment is used to transport the flue and transport the sectional flue to the designated position. Certain deformation will occur during the lifting operation of the flue due to its force condition, but it is not known whether it is elastic deformation or plastic deformation. Therefore, this paper analyzes the stress and strain of the flue during operation by finite element method, and observes and analyzes the influence of plastic deformation on the whole flue
Deformation analysis of running electric hoist
According to the practical engineering application, three-dimensional modeling of electric hoist and I-beam track is carried out, and the model is simplified to determine the electric hoist load, roller acceleration and speed, and the Abaqus software is used to simulate, analyze the simulation results, observe the actual maximum load under the track stress and strain to meet the requirements, calculate the allowable stress, Observe whether it exceeds the allowable stress and whether plastic deformation occurs. If the numerical simulation results of stress and strain are within the safety requirements, the project can be implemented
- …