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Satoshi Matsuda

Publications and source records attributed to Satoshi Matsuda.

11 recordsLinked to original sources
arXiv2006

Cosmological Constant Probing Shape Moduli through Large Extra Dimensions

We consider compactification of extra dimensions and numerically calculate Casimir energy which is provided by the mass of Kaluza-Klein modes. For the extra space we consider a torus with shape moduli and show that the corresponding vacuum energy is represented as a function of the moduli parameter of the extra dimensions. By assuming that the Casimir energy may be identified with cosmological constant, we evaluate the size of extra dimensions in terms of the recent data given by the WMAP observation. We suggest that the observed cosmological constant may probe the shape moduli of the extra space by the study of the Casimir energy of the compactified extra dimensions.

hep-th↗
arXiv2003

Proposal for Generic Size of Large Extra Dimensions

In order to resolve the hierarchy problem, large extra dimensions have been introduced, and it has been suggested that the size of extra dimensions is sub-millimeter. On the other hand, we assume in this paper that the cosmological constant comes from the Casimir energy of extra dimensions and estimate the size of extra dimensions in terms of the value of the cosmological constant discovered by the recent WMAP observations. We demonstrate that this size is consistent with the one derived from the hierarchy problem and propose that there may be a generic size of large extra dimensions when the number of extra dimensions is equal to two.

hep-ph↗
arXiv2001

Gravitational Stability and Screening Effect from Extra Timelike Dimensions

We discuss extra timelike dimensions and their effects on the gravitational stability of spherical massive bodies. Here we specifically report our results for the case of one extra timelike dimension where we have made analytically rigorous investigations on the tachyonic graviton exchange due to the infinite tower of the Kaluza-Klein mode. With the scale $L$ of the extra timelike dimension we find that some spherical bodies of radius $R$ can be stable at critical radii $R=2πLp$ for some positive integer $p$. We also obtain the generic property of massive bodies that for the short distance range $0<R\leq πL$ the gravitational force due to the ordinary massless graviton exchange is screened by the Kaluza-Klein mode exchange of tachyonic gravitons.

hep-th↗
arXiv2000

Gravitational Stability and Screening Effect from D Extra Timelike Dimensions

We study (3+1)+D dimensional spacetime, where D extra dimensions are timelike. Compactification of the D timelike dimensions leads to tachyonic Kaluza-Klein gravitons. We calculate the gravitational self-energies of massive spherical bodies due to the tachyonic exchange, discuss their stability, and find that the gravitational force is screened in a certain number of the extra dimensions. We also derive the exact relationship between the Newton constants in the full 4+D dimensional spacetime with the D extra times and the ordinary Newton constant of our 4 dimensional world.

hep-th↗
arXiv2000

Gravitational Stability and Extra Timelike Dimensions

Tachyonic Kaluza-Klein modes normally appear from the compactification of extra timelike dimensions with scale $L$ and lead to some instabilities of physical systems. We calculate the contribution of tachyonic gravitons to the self energies of spherical massive bodies of radius $R$ and discuss their possible gravitational stability. We find that some spherical bodies can be stable at critical radii $R=2πL p$ for some positive integers $p$. We also prove the generic property of massive bodies that for the range $0<R\leqπL$ the gravitational force due to the ordinary massless graviton exchange is screened by the Kaluza-Klein mode exchange of tachyonic gravitons.

hep-ph↗
arXiv1996

Spectral Flow and Feigin-Fuks Parameter Space of N=4 Superconformal Algebras

The parameter space of the Feigin-Fuks representations of the N=4 SU(2)$_k$ superconformal algebras is studied from the viewpoint of the specral flow. The $η$ phase of the spectral flow is nicely incorporated through twisted fermions and the spectral flow resulting from the inner automorphism of the N=4 superconformal algebras is explicitly shown to be operating as identiy relations among the generators. Conditions for the unitary representations are also investigated in our Feigin-Fuks parameter space.

hep-th↗
arXiv1996

Feigin-Fuchs Representations for Nonequivalent Algebras of N=4 Superconformal Symmetery

The $N=4$ SU(2)$_k$ superconformal algebra has the global automorphism of SO(4) $\approx$ SU(2)$\times$SU(2) with the {\it left} factor as the Kac-Moody gauge symmetry. As a consequence, an infinite set of independent algebras labeled by $ρ$ corresponding to the conjugate classes of the {\it outer} automorphism group SO(4)/SU(2)=SU(2) are obtained à la Schwimmer and Seiberg. We construct Feigin-Fuchs representations with the $ρ$ parameter embedded for the infinite set of the $N=4$ nonequivalent algebras. In our construction the extended global SU(2) algebras labeled by $ρ$ are self-consistently represented by fermion fields with appropriate boundary conditions.

hep-th↗
arXiv1994

More on the Burkhardt-Cottingham Sum Rule in QCD

The QCD higher order effects to the polarized structure function $g_2(x, Q^2 )$ are reanalyzed for massive quarks in the context of the operator product expansion. We confirm that the lowest moment of $g_2 (x, Q^2 )$ which corresponds to the Burkhardt-Cottingham sum rule does {\sl not} suffer from radiative corrections in perturbative QCD.

hep-ph↗
arXiv1994

Representation Blocks of Conformal Fields for the $N$=4 SU(2)$_k$ Superconformal Algebras

The representation theories of the SU(2)$_k$-extended $N$=4 superconformal algebras (SCAs) with $arbitrary$ level $k$ are developed being based on their Feigin-Fuchs representations found recently by the present author. A basic unit of the representation blocks consisting of eight \lq\lq boson-like\rq\rq\ and eight \lq\lq fermion-like\rq\rq\ conformal fields is found to describe arbitrary representations of the $N$=4 SU(2)$_k$ SCAs, including {\it unitary} and {\it nonunitary} representations. The transformation properties of the fundamental sets of the conformal fields under the $N$=4 SU(2)$_k$ superconformal symmetries are given. Then, the whole sets of the charge-screening operators of the $N$=4 SU(2)$_k$ SCAs are identified out of the sixteen conformal fields in the basic unit of the representation blocks. The conditions for the {\it eligible} charge-screening operators are analyzed in terms of the continuous parameters which enter in our vertex-operator forms for the fundamental conformal fields of the representation blocks.

hep-th↗
arXiv1992

Coulomb Gas Representations and Screening Operators of the N=4 Superconformal Algebras

The Coulomb gas representations are presented for the ${\rm SU(2)}$$_k$-extended $N$=4 superconformal algebras, incorporating the Feigin-Fuchs representation of the\break ${\rm SU(2)}$$_k$ Kac-Moody algebra with {\sl arbitrary} level $k$. Then the long-standing problem of identifying the whole set of charge-screening operators for the $N$=4 superconformal algebras is solved and their explicit expressions are given. The method of achieving a rigorous proof of the $N$=4 Kac determinant formulae following Kato and Matsuda is suggested. The complete proof for them will be given elsewhere. Our results for the screening operators also provide the basis for studying the BRST formalism of the $N$=4 superconformal algebras ${\sl {\grave a}\ la}$ Felder.

hep-th↗