45254853
Lattice thermodynamics for gauge theories.
We study the Stefan-Boltzmann formula for a free-gluon gas system in the lattice-regularized thermodynamics, and find that there arises a clear ''Debye effect'' above the temperature T/sub D/ = 1/a/sub sigma/ (a/sub sigma/ being the lattice spacing) and the Stefan-Boltzmann formula deviates from the conventional one in the high-temperature region T>T/sub D/.
118270514
Covariant lagrangian formulation of interacting heterotic strings
A manifestly Lorentz-covarariant lagrangian formulation of the Neveu-Schwarz-Ramond heterotic string interacting with external fields is presented. The action is derived from the action for fully 26-dimensional semi-superstring by a simple ansatz. The internal space compactification occurs automatically from the action. The twist factors associated with the Kac-Moody algebra are involved in the theory without introducing them by hands.
16459641
Interaction between Noncommutative Open Strings and Closed-String Tachyons
We construct a vertex operator that describes the emission of a ground-state tachyon of a closedstring out of a noncommutative open string. Such a vertex operator is shown to exist only when the momentum of the closed-string tachyon is subject to some constraints coming from the background B field. When the non-zero background B fieldis lying only on a D-brane, and both ends of the open string are on the D-brane, the closed-string tachyon is emittedfrom the open string in an orthogonal d irection to the D-brane. The vertex operator has a multiplicative coupling constant g(σ) which depends on σ as g(σ) = sin 2 σ in 0 ≤ σ ≤ π. This behavior is the same as in the ordinary B = 0 case.
121289650
Schwarzian Connections in the Krichever-Novikov Algebra
In the local operator approach to higher-genus Riemann surface we point out an importance of
122739517
Electromagnetic Properties of the Kaluza-Klein String
On calcule le g-facteur magnetique pour la corde dans la theorie de Kaluza-Klein de l'espace-temps a 5 dimensions et on trouve une formule generale des moments magnetiques avec le g-facteur universel de g(J)=1 pour tous les etats de corde
9105602
Charged superstrings in background gauge fields and spectrum-generating algebra
The spectrum-generating algebra (SGA) for charged superstrings placed in constant background magnetic fields is constructed. Contrary to the neutral string this algebra is characteristic of including the cyclotron frequency. The Regge intercept and superconformal anomalies are calculated to be shifted by the cyclotron frequency and Dbrane parameters from the conventional values.
34447702
Collective modes in hot and dense matter.
We propose a model for a relativistic many-body system at finitetemperature in the framework of thermo field dynamics, which is a real-timeformalism of finite-temperature field theory. Our model contains the scalar(sigma) and the vector (..omega..) mesons as well as the Dirac nucleon. Thefull propagator and self-energy for each particle are presented in terms ofspectral representations. The Feynman rules for a perturbation expansion areshown. They are applied to the study of collective modes in hot and densematter within the random-phase approximation. The dispersion relations of thelongitudinal and transverse collective modes in the meson branch arecalculated. We also estimate the effective meson mass which is defined as theenergy needed to create one meson at rest in extreme matter. The effects ofvacuum fluctuations are also examined. They contribute a fair amount to thecollective modes through the effective nucleon mass.
15911146
Variations of hadron masses and matter properties in dense nuclear matter.
Using a self-consistent quark model for nuclear matter we investigate variations of the masses of the nonstrange vector mesons, the hyperons, and the nucleon in dense nuclear matter (up to four times the normal nuclear density). We find that the changes in the hadron masses can be described in terms of the value of the scalar mean field in matter. The model is then used to calculate the density dependence of the quark condensate in-medium, which turns out to be well approximated by a linear function of the nuclear density. Some relations among the hadron properties and the in-medium quark condensate are discussed.
55538978
HIGH GRADIENT BEHAVIORS OF LARGE GRAIN ICHIRO SINGLE CELL CAVITY BY CHEMICAL POLISHING
We have started high gradient R&D with the combination of ICHIRO shape, sliced large grain niobium, and buffered chemical polishing (BCP). We fabricated one large grain ICHIRO single cell cavity that had end cell shape of ICHIRO 9-cell but no end group. We processed this cavity surface by centrifugal barrel polishing (CBP) and BCP. This cavity successfully achieved the high gradient of 42MV/m at the first vertical test. We made series test by repeating BCP on this cavity. The results of the series test will be reported. INTRODUCTION Large grain niobium SRF cavities have been developed in many laboratories, Jlab, DESY, IHEP, KEK, and so on. Our KEK LL group made breakthrough of LG Nb sheet production in 2008 [1]. We have successfully developed the multi-wire slicing method for niobium ingots with 270mm diameter collaborating with KEK, Tokyo Denkai Co. Ltd., TKX Co.Ltd., and Toyo Advanced Technologies Co. Ltd. This technology can reduce the cost of Nb sheet productions. LG cavity also can achieve high gradient of 40MV/m by BCP, not by electro polishing (EP) [2]. In order to make the breakthrough of ILC cavity cost, we are proposing the combination of sliced LG Nb materials + ICHIRO shape + BCP. This could promise the cheap, easy, and high reliable performance cavity production. In this paper, we will describe about our R&D on LG single cell cavity made of sliced Nb sheets.
10938062
Composite nucleons in scalar and vector mean fields.
We emphasize that the composite structure of the nucleon may play quite an important role in nuclear physics. It is shown that the momentum-dependent repulsive force of second order in the scalar field, which plays an important role in Dirac phenomenology, can be found in the quark-meson coupling (QMC) model, and that the properties of nuclear matter are well described through the quark-scalar density in a nucleon and a self-consistency condition for the scalar field. The difference between theories of pointlike nucleons and composite ones may be seen in the change of the {omega}-meson mass in nuclear matter if the composite nature of the nucleon suppresses contributions from nucleon-antinucleon pair creation.
20298579
Relativistic hydrodynamics of quark-gluon plasma and stability of scaling solutions.
The scaling solutions of the relativistic hydrodynamics are expected to play an important role in describing the expansion stage of a quark-gluon plasma which may be formed in nucleus-nucleus collisions at high energies. After summarizing some general properties of the scaling solutions, we study in detail their stability against small perturbations. In some typical cases of the two-dimensional scaling solution it is found that (i) the scaling solution is stable if the Reynolds number {ital R} defined in terms of the viscosity coefficients is larger than a critical value {ital R}{sub {ital c}} (=1), (ii) it is also stable for a long-wavelength perturbation if {ital R} is small enough, and (iii) it becomes unstable when {ital R} approaches {ital R}{sub {ital c}} from below. It is also shown that these results are related to the time dependence of the Reynolds number, the entropy density, and the temperature, and the point {ital R}={ital R}{sub {ital c}} corresponds to a critical instant when the heating due to the dissipative processes balances with the cooling due to the expansion of the fluid. The stability of the scaling solution of the quark-gluon plasma is examined for typical ranges of the relevant parameters.