118392464
Relevant momentum components of gluons for confinement and chiral symmetry breaking
We investigate which momentum components of gluons induce color confinement and spontaneous chiral symmetry breaking in lattice QCD. For this purpose, we formulate a lattice framework to introduce the momentum cutoff of the gluon field. Using this framework, we calculate the quark-antiquark potential, the color flux tube, the chiral condensate, and the Dirac spectrum. Our results suggest that confinement and chiral symmetry breaking are induced by somehow different momentum components of gluons.
119220877
Lattice study of the chiral magnetic effect in a chirally imbalanced matter
We investigate the chiral magnetic effect by lattice QCD with a chiral chemical potential. In a chirally imbalanced matter, we obtain a finite induced current along an external magnetic field. We analyze the dependence on the lattice spacing, the temperature, the spatial volume, and the fermion mass. The present result indicates that the continuum limit is important for the quantitative argument of the strength of the induced current.
122884910
Temporal chiral spiral in QCD in the presence of strong magnetic fields
Vacuum properties of quantum chromodynamics in strong magnetic and nite electric elds are investigated. We show that when a uniform electric eld is instantaneously applied in the parallel direction to a strong magnetic eld, it induces temporal oscillation of the scalar and pseudoscalar condensates. This is a temporal analog to the chiral spiral. The oscillation originates with the propagation of the collective mode, which is protected by the axial anomaly and thus is nondissipative.
118399960
Lattice QCD Anatomy via the Energy-Momentum Component of Gluons
In this thesis, we perform the lattice QCD analysis via the energy-momentum component of gluons. By introducing the momentum cutoff to the link variable, we investigate which energy-momentum components of gluons induce each QCD phenomenon. We use the Landau gauge for the most part of the lattice QCD analysis. In lattice QCD, we analyze color confinement, spontaneous chiral symmetry breaking, topological charge, and the related topics. We also discuss several comparisons with effective theories. As for color confinement, we calculate the quark-antiquark potential, the color flux tube, and meson masses. From quantitative analysis, we find that color confinement is induced by the low-momentum component below 1.5 GeV. As for spontaneous chiral symmetry breaking, we calculate the chiral condensate and the Dirac spectrum. Spontaneous chiral symmetry breaking is induced by the broad low-momentum component which ranges even above 1.5 GeV. The present result suggests that color confinement and spontaneous chiral symmetry breaking are induced by somehow different energy-momentum components of gluons. As for topological charge, we calculate the topological charge density and the Dirac zero mode. Topological charge is induced by the broad energy-momentum component, which is similar to spontaneous chiral symmetry breaking.
119245257
QCD Dirac spectrum and components of the gauge field
Abstract We analyze the relation between the Dirac spectrum and the gauge field in SU(3) lattice QCD. We focus on how a certain component of the gauge field is related to the Dirac spectrum. First, we consider momentum components of the gauge field. It turns out that the broad momentum region is relevant for the low-lying Dirac spectrum and topological charges. The connection with chiral random matrix theory is also discussed. Second, we consider an SU(2) subgroup component of the SU(3) gauge field. The SU(2) subgroup component behaves like the SU(2) gauge field in the low-lying Dirac spectrum.
56393007
Lattice QCD simulation at finite chiral chemical potential
Chiral chemical potential does not cause the sign problem in the Monte Carlo simulation of lattice QCD. Using the chiral chemical potential, we study the chiral magnetic effect in two-flavor full QCD. We show that a strong external magnetic field induces an electric current in a chirally imbalanced QCD matter. The qualitative feature of the induced current is consistent with an analytical prediction.
21013020
Conduction Cooling Test of a Splittable Quadrupole for ILC Cryomodules
A superconducting splittable quadrupole magnet was designed at Fermilab for use in ILC-style cryomodules, in which the magnet is to be assembled around the beam tube to avoid contaminating the ultraclean superconducting RF beam volume. This quadrupole was built and first tested in a liquid helium bath environment at Fermilab, where its quench and magnetic performance were characterized. The device is intended to be cooled by conduction when installed in cryomodules, so a separate test was made at KEK where an appropriate conduction cooling test facility exists. We present results of the thermal performance of the magnet in the conduction cooling mode, and discuss its excitation characteristics in this operating mode.
113855195
Studies of Fabrication Procedure of 9-cell SRF Cavity for ILC Mass-production at KEK.
We had been constructing a new facility for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we have installed a deepdrawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the studies on the fabrication of 9-cell cavity for International Linear Collier (ILC) using this facility. The studies are focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We already finished the fabrication of two 9-cell cavities in this facility. This article reports the current status of the studies.