Fine Tuning in General Gauge Mediation (2009)
Kobayashi, Tatsuo, Nakai, Yuichiro, Takahashi, Ryo
We study the fine-tuning problem in the context of general gauge mediation. Numerical analyses toward for relaxing fine-tuning are presented. We analyse the problem in typical three cases of the...
Non-Abelian discrete flavor symmetries from magnetized/intersecting brane models (2009)
Abe, Hiroyuki, Choi, Kang-Sin, Kobayashi, Tatsuo, Ohki, Hiroshi
We study non-Abelian discrete flavor symmetries, which appear in magnetized brane models. For example, D4, Δ (27) and Δ (54) flavor symmetries can appear with matter fields in several...
E6,7,8 Magnetized Extra Dimensional Models (2009)
Choi, Kang-Sin, Kobayashi, Tatsuo, Maruyama, Ryosuke, Murata, Masaki, Nakai, Yuichiro, Ohki, Hiroshi, ...
We study 10D super Yang-Mills theory with the gauge groups $E_6$, $E_7$ and $E_8$. We consider the torus/orbifold compacfitication with magnetic fluxes and Wilson lines. They lead to 4D interesting...
Magnetic flux, Wilson line and orbifold (2009)
Abe, Hiroyuki, Choi, Kang-Sin, Kobayashi, Tatsuo, Ohki, Hiroshi
We study torus/orbifold models with magnetic flux and Wilson line background. The number of zero-modes and their profiles depend on those backgrounds. That has interesting implications from the...
Delta(54) Flavor Model for Leptons and Sleptons (2009)
Ishimori, Hajime, Kobayashi, Tatsuo, Okada, Hiroshi, Shimizu, Yusuke, Tanimoto, Morimitsu
We have studied $\Delta(54)\times Z_2$ flavor model for leptons and sleptons. The tri-bimaximal mixing can be reproduced for arbitrary neutrino masses if vacuum alignments of scalar fields are...
Non-Abelian Discrete Flavor Symmetries from Magnetized/Intersecting Brane Models (2009)
Abe, Hiroyuki, Choi, Kang-Sin, Kobayashi, Tatsuo, Ohki, Hiroshi
We study non-abelian discrete flavor symmetries, which can appear in magnetized brane models. For example, $D_4$, $\Delta(27)$ and $\Delta(54)$ can appear and matter fields with several...
Higher Order Couplings in Magnetized Brane Models (2009)
Abe, Hiroyuki, Choi, Kang-Sin, Kobayashi, Tatsuo, Ohki, Hiroshi
We compute three-point and higher order couplings in magnetized brane models. We show that higher order couplings are written as products of three-point couplings. This behavior is the same as higher...
Three generation magnetized orbifold models (2008)
Abe, Hiroyuki, Choi, Kang-Sin, Kobayashi, Tatsuo, Ohki, Hiroshi
We study three generation models in the four-dimensional spacetime, which can be derived from the ten-dimensional N=1 super Yang-Mills theory on the orbifold background with a non-vanishing magnetic...
Lepton Flavor Model from Delta(54) Symmetry (2008)
Ishimori, Hajime, Kobayashi, Tatsuo, Okada, Hiroshi, Shimizu, Yusuke, Tanimoto, Morimitsu
We present the lepton flavor model with $\Delta (54)$, which appears typically in heterotic string models on the $T^2/Z_3$ orbifold. Our model reproduces the tri-bimaximal mixing in the parameter...
Duality cascade of softly broken supersymmetric theories (2008)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo, Ohta, Kazutoshi, Omura, Yuji, Terao, Haruhiko
We study the duality cascade of softly broken supersymmetric theories. We investigate the renormalization group (RG) flow of SUSY breaking terms as well as supersymmetric couplings. It is found that...
Flavor Symmetry Breaking and Vacuum Alignment on Orbifolds (2008)
Kobayashi, Tatsuo, Omura, Yuji, Yoshioka, Koichi
Flavor symmetry has been widely studied for figuring out the masses and mixing angles of standard-model fermions. In this paper we present a framework for handling flavor symmetry breaking where the...
Soft supersymmetry breaking terms from A4 lepton flavor symmetry (2008)
Ishimori, Hajime, Kobayashi, Tatsuo, Omura, Yuji, Tanimoto, Morimitsu
We study the supersymmetric model with the A4 lepton flavor symmetry, in particular soft supersymmetry breaking terms, which are predicted from the A4 lepton flavor symmetry. We evaluate soft slepton...
Magnetized orbifold models (2008)
Abe, Hiroyuki, Kobayashi, Tatsuo, Ohki, Hiroshi
We study (4+2n)-dimensional N=1 super Yang-Mills theory on the orbifold background with non-vanishing magnetic flux. In particular, we study zero-modes of spinor fields. The flavor structure of our...
(Non-)Abelian discrete anomalies (2008)
Araki, Takeshi, Kobayashi, Tatsuo, Kubo, Jisuke, Ramos-Sanchez, Saul, Ratz, Michael, Vaudrevange, Patrick K. S.
We derive anomaly constraints for Abelian and non-Abelian discrete symmetries using the path integral approach. We survey anomalies of discrete symmetries in heterotic orbifolds and find a new...
Non-perturbative moduli superpotential with positive exponents (2008)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo, Seto, Osamu
Submitted on 21 Apr 2008 (v1), last revised 24 Apr 2008 (this version, v2).-- 13 pages, 4 figures.-- v2: reference added.
Non-perturbative moduli superpotential with positive exponents (2008)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo, Seto, Osamu
We study non-perturbative moduli superpotentials with positive exponents, i.e. the form like $Ae^{aT}$ with a positive constant $a$ and the modulus $T$. These effects can be generated, e.g., by...
Soft supersymmetry breaking terms from D4 x Z2 lepton flavor symmetry (2008)
Ishimori, Hajime, Kobayashi, Tatsuo, Ohki, Hiroshi, Omura, Yuji, Takahashi, Ryo, Tanimoto, Morimitsu
We study the supersymmetric model with $D_4 \times Z_2$ lepton flavor symmetry. We evaluate soft supersymmetry breaking terms, i.e. soft slepton masses and A-terms, which are predicted in the $D_4$...
D4 Flavor Symmetry for Neutrino Masses and Mixing (2008)
Ishimori, Hajime, Kobayashi, Tatsuo, Ohki, Hiroshi, Omura, Yuji, Takahashi, Ryo, Tanimoto, Morimitsu
We present the $D_4\times Z_2$ flavor symmetry, which is different from the previous work by Grimus and Lavoura. Our model reduces to the standard model in the low energy and there is no FCNC at the...
Dynamically sequestered F-term uplifting in extra dimension (2008)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo, Omura, Yuji
We study concretely several issues altogether, moduli stabilization, the dynamical supersymmetry (SUSY) breaking, the uplifting of SUSY anti-de Sitter (AdS) vacuum and the sequestering of hidden...
Metastable supersymmetry breaking vacua from conformal dynamics (2007)
Abe, Hiroyuki, Kobayashi, Tatsuo, Omura, Yuji
We study the scenario that conformal dynamics leads to metastable supersymmetry breaking vacua. At a high energy scale, the superpotential is not R-symmetric, and has a supersymmetric minimum....
Higher Order Couplings from Heterotic Orbifold Theory (2007)
Choi, Kang-Sin, Kobayashi, Tatsuo
We calculate couplings of arbitrary order from correlation functions among twisted strings, using conformal field theory. Twisted strings arise in heterotic string compactified on orbifolds yielding...
Prospects for the direct detection of neutralino dark matter in orbifold scenarios (2007)
Cerdeño, David G., Kobayashi, Tatsuo, Muñoz, Carlos
51 pages, 25 figures.
Abe, Hiroyuki, Kobayashi, Tatsuo, Omura, Yuji
We study N=1 global and local supersymmetric theories with a continuous global $U(1)_R$ symmetry as models of dynamical supersymmetry (SUSY) breaking. We introduce explicit R-symmetry breaking terms...
More about F-term uplifting (2007)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo
We study moduli stabilization and a realization of de Sitter vacua in generalized F-term uplifting scenarios of the KKLT-type anti-de Sitter vacuum, where the uplifting sector X directly couples to...
TeV scale partial mirage unification and neutralino dark matter (2007)
Abe, Hiroyuki, Kim, Yeong Gyun, Kobayashi, Tatsuo, Shimizu, Yasuhiro
We study the TeV scale partial mirage unification scenario, where the gluino and wino masses are degenerate around a TeV scale, but the bino mass is not degenerate. This scenario has...
Discrete R-symmetry anomalies in heterotic orbifold models (2007)
Araki, Takeshi, Choi, Kang-Sin, Kobayashi, Tatsuo, Kubo, Jisuke, Ohki, Hiroshi
Anomalies of discrete R-symmetries appearing in heterotic orbifold models are studied. We find that the mixed anomalies for different gauge groups satisfy the universal Green-Schwarz (GS) condition,...
String-derived D4 flavor symmetry and phenomenological implications (2007)
Ko, Pyungwon, Kobayashi, Tatsuo, Park, Jae-hyeon, Raby, Stuart
In this paper we show how some flavor symmetries may be derived from the heterotic string, when compactified on a 6D orbifold. In the body of the paper we focus on the $D_4$ family symmetry, recently...
Relaxed fine-tuning in models with non-universal gaugino masses (2007)
Abe, Hiroyuki, Kobayashi, Tatsuo, Omura, Yuji
We study, in a bottom-up approach, the fine-tuning problem between soft SUSY breaking parameters and the $\mu$-term for the successful electroweak symmetry breaking in the minimal supersymmetric...
TeV Scale Mirage Mediation and Natural Little SUSY Hierarchy (2006)
Choi, Kiwoon, Jeong, Kwang Sik, Kobayashi, Tatsuo, Okumura, Ken-ichi
TeV scale mirage mediation has been proposed as a supersymmetry breaking scheme reducing the fine tuning for electroweak symmetry breaking in the minimal supersymmetric extension of the standard...
Non-Factorisable Z2 times Z2 Heterotic Orbifold Models and Yukawa Couplings (2006)
Forste, Stefan, Kobayashi, Tatsuo, Ohki, Hiroshi, Takahashi, Kei-jiro
We classify compactification lattices for supersymmetric Z2 times Z2 orbifolds. These lattices include factorisable as well as non-factorisable six-tori. Different models lead to different numbers of...
Stringy origin of non-Abelian discrete flavor symmetries (2006)
Kobayashi, Tatsuo, Nilles, Hans Peter, Plöger, Felix, Raby, Stuart, Ratz, Michael
We study the origin of non-Abelian discrete flavor symmetries in superstring theory. We classify all possible non-Abelian discrete flavor symmetries which can appear in heterotic orbifold models....
Moduli stabilization, F-term uplifting and soft supersymmetry breaking terms (2006)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo, Omura, Yuji
We study moduli stabilization with F-term uplifting. As a source of uplifting F-term, we consider spontaneous supersymmetry breaking models, e.g. the Polonyi model and the Intriligator-Seiberg-Shih...
Time variation of proton-electron mass ratio and fine structure constant with runaway dilaton (2006)
Chiba, Takeshi, Kobayashi, Tatsuo, Yamaguchi, Masahide, Yokoyama, Jun'ichi
Recent astrophysical observations indicate that the proton-electron mass ratio and the fine structure constant have gone through nontrivial time evolution. We discuss their time variation in the...
Dynamical realization of democratic Yukawa matrices and alignment of a terms (2006)
Kobayashi, Tatsuo, Omura, Yuji, Terao, Haruhiko
We study realization of the democratic form of Yukawa matrices by infrared fixed points. We investigate renormalization-group flows of Yukawa couplings in models with a single Yukawa matrix for three...
Fine-tuning in gauge mediated supersymmetry breaking models and induced top Yukawa coupling (2006)
Kobayashi, Tatsuo, Terao, Haruhiko, Tsuchiya, Akito
It is shown that fine-tuning of the Higgs parameters stronger than a few percent is required at best in the models with gauge mediated supersymmetry breaking. With the aim of solving this problem, we...
Remark on integrating out heavy moduli in flux compactification (2006)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo
We study two steps of moduli stabilization in type IIB flux compactification with gaugino condensations. We consider the condition that one can integrate out heavy moduli first with light moduli...
Dynamical realization of democratic Yukawa matrices and alignment of A-terms (2006)
Kobayashi, Tatsuo, Omura, Yuji, Terao, Haruhiko
We study realization of the democratic form of Yukawa matrices by infrared fixed points. We investigate renormalization-group flows of Yukawa couplings in models with a single Yukawa matrix for three...
Fine-tuning in gauge mediated supersymmetry breaking models and induced top Yukawa coupling (2006)
Kobayashi, Tatsuo, Terao, Haruhiko, Tsuchiya, Akito
It is shown that fine-tuning of the Higgs parameters stronger than a few % is required at the best in the models with gauge mediated supersymmetry breaking. With the aim of solving this problem, we...
Moduli-mixing racetrack model (2005)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo
We study supersymmetric models with double gaugino condensations in the hidden sector, where the gauge couplings depend on two light moduli of superstring theory. We perform a detailed analysis of...
KKLT type models with moduli-mixing superpotential (2005)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo
We study KKLT type models with moduli-mixing superpotential. In several string models, gauge kinetic functions are written as linear combinations of two or more moduli fields. Their gluino...
More about soft terms and FCNC in realistic string constructions (2005)
Kobayashi, Tatsuo, Munoz, Carlos
In realistic four-dimensional string constructions the presence of anomalous U(1)'s is generic. In addition, the associated Fayet-Iliopoulos contribution to the D-term can break the extra gauge...
Little SUSY hierarchy in mixed modulus-anomaly mediation (2005)
Choi, Kiwoon, Jeong, Kwang Sik, Kobayashi, Tatsuo, Okumura, Ken-ichi
Motivated by the KKLT string compactification involving a supersymmetry-breaking uplifting potential, we examine 4D effective supergravity with a generic form of uplifting potential, focusing on the...
Induced top-Yukawa coupling and suppressed Higgs mass parameters (2005)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
In the scenarios with heavy top squarks, mass parameters of the Higgs field must be fine-tuned due to a large logarithmic correction to the soft scalar mass. We consider a new possibility that the...
Flavor structure and coupling selection rule from intersecting D-branes (2005)
Higaki, Tetsutaro, Kitazawa, Noriaki, Kobayashi, Tatsuo, Takahashi, Kei-jiro
We study flavor structure and the coupling selection rule in intersecting D-brane configurations. We formulate the selection rule for Yukawa couplings and its extensions to generic n-point couplings....
Lepton masses and mixing angles from heterotic orbifold models (2005)
Ko, Pyungwon, Kobayashi, Tatsuo, Park, Jae-hyeon
We systematically study the possibility for realizing realistic values of lepton mass ratios and mixing angles by using only renormalizable Yukawa couplings derived from heterotic $Z_6$-I orbifold....
Induced top Yukawa coupling and suppressed Higgs mass parameters (2005)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
In the scenarios with heavy top squarks, mass parameters of the Higgs field must be fine-tuned due to a large logarithmic correction to the soft scalar mass. We consider a new possibility that the...
Democratic mass matrices induced by strong gauge dynamics and large mixing angles for leptons (2004)
Kobayashi, Tatsuo, Shirano, Hiroaki, Terao, Haruhiko
We consider dynamical realization of the democratic type Yukawa coupling matrices as the Pendelton-Ross infrared fixed points.?Such fixed points of the Yukawa couplings become possible by introducing...
Large Mass Scale by Strong Gauge Dynamics with Infrared Fixed Point (2004)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko, Yamada, Yoshihisa
We consider a mechanism for realizing the desired decoupling of strongly-coupled sector which is supposed to generate hierarchical structure of the Yukawa couplings. In our mechanism, the same...
Radiative stabilization of warped space (2004)
Kobayashi, Tatsuo, Yoshioka, Koichi
Higher-dimensional field theory has been applied to explore various issues in recent particle physics such as the gauge hierarchy problem. In order for such approaches to be viable, a crucial...
Kobayashi, Tatsuo, Raby, Stuart, Zhang, Ren-Jie
Motivated by orbifold grand unified theories, we construct a class of three-family Pati-Salam models in a Z6 abelian symmetric orbifold with two discrete Wilson lines. These models have marked...
Yukawa Coupling Structure in Intersecting D-brane Models (2004)
Kitazawa, Noriaki, Kobayashi, Tatsuo, Maru, Nobuhito, Okada, Nobuchika
The structure of Yukawa coupling matrices is investigated in type IIA T^6/(Z_2 x Z_2) orientifold models with intersecting D-branes. Yukawa coupling matrices are difficult to be realistic in the...
Quark masses and mixing angles in heterotic orbifold models (2004)
Ko, Pyungwon, Kobayashi, Tatsuo, Park, Jae-hyeon
We study systematically the possibility for realizing realistic values of quark mass ratios $m_c/m_t$ and $m_s/m_b$ and the mixing angle $V_{cb}$ by using only renormalizable Yukawa couplings derived...
Suppressed supersymmetry breaking terms in the Higgs sector (2004)
Kobayashi, Tatsuo, Terao, Haruhiko
We study the little hierarchy between mass parameters in the Higgs sector and other SUSY breaking masses. This type of spectrum can relieve the fine-tuning problem in the MSSM Higgs sector. Our...
Constructing 5d orbifold grand unified theories from heterotic strings (2004)
Kobayashi, Tatsuo, Raby, Stuart, Zhang, Ren-Jie
A three-generation Pati-Salam model is constructed by compactifying the heterotic string on a particular T^6/Z_6 Abelian symmetric orbifold with two discrete Wilson lines. The compactified space is...
D-term Inflation and Nonperturbative Kahler Potential of Dilaton (2004)
Higaki, Tetsutaro, Kobayashi, Tatsuo, Seto, Osamu
We study the $D$-term inflation scenario with a nonperturbative K\"ahler potential of the dilaton field. Although the FI term which leads an inflationary expansion is given by the derivative of the...
Non-perturbative Kahler Potential, Dilaton Stabilization and Fayet-Iliopoulos Term (2003)
Higaki, Tetsutaro, Kawamura, Yoshiharu, Kobayashi, Tatsuo, Nakano, Hiroaki
We study the dilaton stabilization in models with anomalous U(1) symmetry by adding specific string-motivated, non-perturbative corrections to the tree-level dilaton K\"{a}hler potential. We find...
Localization of heterotic anomalies on various hyper surfaces of T^6/Z_4 (2003)
Nibbelink, Stefan Groot, Hillenbach, Mark, Kobayashi, Tatsuo, Walter, Martin G. A.
We investigate the structure of local anomalies of heterotic E_8 x E_8' theory on T^6/Z_4. We show that the untwisted states lead to anomalies in ten, six and four dimensions. At each of the six...
Anomalous U(1) D-term Contribution in Type I String Models (2003)
Higaki, Tetsutaro, Kawamura, Yoshiharu, Kobayashi, Tatsuo, Nakano, Hiroaki
We study the $D$-term contribution for anomalous U(1) symmetries in type I string models and derive general formula for the $D$-term contribution, assuming that the dominant source of SUSY breaking...
Dilaton and Moduli Fields in D-term inflation (2003)
Kobayashi, Tatsuo, Seto, Osamu
We investigate the possibility of $D$-term inflation within the framework of type I string-inspired models. Although $D$-term inflation model has the excellent property that it is free from the...
Supersymmetry Breaking in Warped Geometry (2003)
Choi, Kiwoon, Kim, Do Young, Kim, Ian-Woo, Kobayashi, Tatsuo
We examine the soft supersymmetry breaking parameters in supersymmetric theories on a slice of AdS_5 which generate the hierarchical Yukawa couplings by dynamically localizing the bulk matter fields...
Heterotic string backgrounds and CP violation (2003)
Kobayashi, Tatsuo, Lebedev, Oleg
In the framework of $Z_N$ orbifolds, we discuss effects of heterotic string backgrounds including discrete Wilson lines on the Yukawa matrices and their connection to CP violation.
Twisted Moduli Stabilization in Type I String Models (2003)
Higaki, Tetsutaro, Kobayashi, Tatsuo
We consider the model with the dilaton and twisted moduli fields, which is inspired by type I string models. Stabilization of their vacuum expectation values is studied. We find the stabilization of...
Exact $S_3$ symmetry solving the supersymmetric flavor problem (2003)
Kobayashi, Tatsuo, Kubo, Jisuke, Terao, Haruhiko
The exact discrete flavor symmetry, $S_3$ in the hadronic sector and $S_3 \times Z_2$ in the leptonic sector, which has been recently found, is introduced in a supersymmetric extension of the...
Heterotic Yukawa couplings and continuous Wilson lines (2003)
Kobayashi, Tatsuo, Lebedev, Oleg
Realistic heterotic string models require the presence of the Wilson lines. We study the effect of continuous Wilson lines on the heterotic Yukawa couplings and find that the presence of continuous...
SUSY Flavor Problem and Warped Geometry (2003)
Choi, Kiwoon, Kim, Do Young, Kim, Ian-Woo, Kobayashi, Tatsuo
We point out that supersymmetric warped geometry can provide a solution to the SUSY flavor problem, while generating hierarchical Yukawa couplings. In supersymmetric theories in a slice of AdS_5 with...
Finite Theories and the SUSY Flavor Problem (2002)
Babu, K. S., Kobayashi, Tatsuo, Kubo, Jisuke
We study a finite SU(5) grand unified model based on the non-Abelian discrete symmetry A_4. This model leads to the democratic structure of the mass matrices for the quarks and leptons. In the soft...
Flavor violation in supersymmetric theories with gauged flavor symmetries (2002)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko, Yoshioka, Koichi
In this paper we study flavor violation in supersymmetric models with gauged flavor symmetries. There are several sources of flavor violation in these theories. The dominant flavor violation is the...
Sfermion mass degeneracy, superconformal dynamics, and supersymmetric grand unified theories (2002)
Kobayashi, Tatsuo, Nakano, Hiroaki, Noguchi, Tatsuya, Terao, Haruhiko
We discuss issues in a scenario where hierarchical Yukawa couplings are generated through the strong dynamics of superconformai field theories (SCFTs). Independently of the mediation mechanism of...
Wave-function profile and SUSY breaking in 5D model with Fayet-Iliopoulos terms (2002)
Abe, Hiroyuki, Higaki, Tetsutaro, Kobayashi, Tatsuo
We systematically study VEVs of a gauge scalar field $\Sigma$ in a bulk U(1) vector multiplet and scalar fields in brane/bulk hypermultiplets charged under U(1) in the 5D $S^1/Z_2$ orbifold model...
Field localization in warped gauge theories (2002)
Abe, Hiroyuki, Kobayashi, Tatsuo, Maru, Nobuhito, Yoshioka, Koichi
We present four-dimensional gauge theories that describe physics on five-dimensional curved (warped) backgrounds, which includes bulk fields with various spins (vectors, spinors, and scalars). Field...
Kobayashi, Tatsuo, Nakano, Hiroaki, Noguchi, Tatsuya, Terao, Haruhiko
We propose a scenario that leads to hierarchical Yukawa couplings and degenerate sfermion masses at the same time, in the context of extra-dimensional models, which can be naturally embedded in a...
Sfermion Mass Degeneracy, Superconformal Dynamics and Supersymmetric Grand Unified Theories (2002)
Kobayashi, Tatsuo, Nakano, Hiroaki, Noguchi, Tatsuya, Terao, Haruhiko
We discuss issues in a scenario that hierarchical Yukawa couplings are generated through strong dynamics of superconformal field theories (SCFTs). Independently of mediation mechanism of...
Yukawa hierarchy transfer from the superconformal sector and degenerate sfermion masses (2001)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
We propose a new type of supersymmetric model coupled to superconformal (SC) field theories, leading simultaneously to hierarchical Yukawa couplings and completely degenerate sfermion masses. We...
4D construction of bulk supersymmetry breaking (2001)
Kobayashi, Tatsuo, Maru, Nobuhito, Yoshioka, Koichi
In this letter, we discuss a four-dimensional model with modulus fields which are responsible for supersymmetry breaking. Given non-trivial moduli dependence of the action, the model is found to give...
Kobayashi, Tatsuo, Terao, Haruhiko
We study soft supersymmetric (SUSY) breaking parameters in the Nelson-Strassler-type models: SUSY standard models coupled with superconformal field theories (SCFT's). In this type of model, soft SUSY...
More about Kaluza-Klein Regularization (2001)
Kobayashi, Tatsuo, Terao, Haruhiko
We study the so-called ``Kaluza-Klein regularization''. We calculate one-loop corrections to the Higgs mass due to Kaluza-Klein modes explicitly in a model with SUSY breaking mass splitting between...
Yukawa Hierarchy Transfer from Superconformal Sector and Degenerate Sfermion Masses (2001)
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
We propose a new type of supersymmetric models coupled to superconformal field theories (SCFT's), leading simultaneously to hierarchical Yukawa couplings and completely degenerate sfermion masses. We...
Sfermion masses in Nelson-Strassler type of models: SUSY standard models coupled with SCFTs (2001)
Kobayashi, Tatsuo, Terao, Haruhiko
We study soft SUSY breaking parameters in the Nelson-Strassler type of models: SUSY standard models coupled with SCFTs. In this type of models, soft SUSY breaking parameters including sfermion masses...
We study soft SUSY breaking terms in heterotic M-theory. We show that both weakly and strongly coupled heterotic string models lead to the same relations of soft SUSY breaking terms, $A=-M$ and $m^2...
Direct Detection of Neutralino Dark Matter and the Anomalous Dipole Moment of the Muon (2000)
Drees, Manuel, Kim, Yeong Gyun, Kobayashi, Tatsuo, Nojiri, Mihoko M.
We compare predictions for the spin-independent contribution to the neutralino-proton scattering cross section $\sig$ and for the anomalous magnetic dipole moment of the muon, $a_\mu = (g_\mu-2)/2$,...
Fermion Mass Hierarchies and Small Mixing Angles from Extra Dimensions (2000)
Bando, Masako, Kobayashi, Tatsuo, Noguchi, Tatsuya, Yoshioka, Koichi
In this paper we study renormalization-group evolutions of Yukawa matrices enhanced by Kaluza-Klein excited modes and analyze their infrared fixed-point structure. We derive necessary conditions to...
Kaluza-Klein Mediated Supersymmetry Breaking (2000)
Kobayashi, Tatsuo, Yoshioka, Koichi
We discuss a framework for communicating supersymmetry breaking to the visible sector where the radius modulus, which determines the size of extra dimensions, has an auxiliary vacuum expectation...
Softly Broken Supersymmetric Gauge-Higgs-Yukawa Theories as Renormalizable Composite Models (2000)
Kobayashi, Tatsuo, Terao, Haruhiko
We examine the (softly broken) supersymmetric gauge-Higgs-Yukawa theories satisfying the compositeness conditions at a certain scale. In these theories the Higgs superfields can be regarded as the...
Infrared alignment of SUSY flavor structures (2000)
Kobayashi, Tatsuo, Yoshioka, Koichi
The various experimental bounds on flavor-changing interactions severely restrict the low-energy flavor structures of soft supersymmetry breaking parameters. In this work, we show that with a...
New RG-invariants of Soft Supersymmetry Breaking Parameters (2000)
Kobayashi, Tatsuo, Yoshioka, Koichi
We study new renormalization-group invariant quantities of soft supersymmetry breaking parameters other than the ratio of gaugino mass to gauge coupling squared by using the spurion method. The...
RG-invariant Sum Rule in a Generalization of Anomaly Mediated SUSY Breaking Models (2000)
Carena, Marcela, Huitu, Katri, Kobayashi, Tatsuo
We study a generalization of anomaly-mediated supersymmetry breaking (AMSB) scenarios, under the assumption that the effects of the high-scale theory do not completely decouple and D-term type...
EDM-free supersymmetric CP violation with non-universal soft terms (2000)
Khalil, Shaaban, Kobayashi, Tatsuo, Vives, Oscar
Non-universality in the soft breaking terms is a common feature in most superstring inspired SUSY models. This property is required to obtain sizeable CP violation effects from SUSY and, on the other...
Yukawa hierarchy from extra dimensions and infrared fixed points (2000)
Bando, Masako, Kobayashi, Tatsuo, Noguchi, Tatsuya, Yoshioka, Koichi
We discuss the existence of hierarchy of Yukawa couplings in the models with extra spatial dimensions. The hierarchical structure is induced by the power behavior of the cutoff dependence of the...
Generic Gravitational Corrections to Gauge Couplings in SUSY SU(5) GUTs (1999)
Huitu, Katri, Kawamura, Yoshiharu, Kobayashi, Tatsuo, Puolamaki, Kai
We study non-universal corrections to the gauge couplings due to higher dimensional operators in supersymmetric SU(5) grand unified theories. The corrections are, in general, parametrized by three...
F-term Inflation in M-theory with Five-branes (1999)
Kobayashi, Tatsuo, Shimabukuro, Hitoshi
We study F-term inflation in M-theory with and without five-brane moduli fields. We show the slow rolling condition is not satisfied in M-theory without five-brane moduli fields, but it can be...
Huitu, Katri, Kobayashi, Tatsuo
We study the gauge coupling unification with extra dimensions. We take into account corrections due to the higher dimensional operators. We show the prediction of $\alpha_3(M_Z)$ is sensitive to such...
Supersymmetric CP violation $\epsilon'/\epsilon$ due to asymmetric A-matrix (1999)
Khalil, Shaaban, Kobayashi, Tatsuo
We study contributions of supersymmetric CP phases to the CP violation $\epsilon'/\epsilon$ in models with asymmetric $A$-matrices. We consider asymmetric $A$-matrices, which are obtained from...
CP violation in supersymmetric model with non-degenerate A-terms (1999)
Khalil, Shaaban, Kobayashi, Tatsuo, Masiero, Antonio
We study the CP phases of the soft supersymmetry breaking terms in string-inspired models with non-universal trilinear couplings. We show that such non-universality plays an important role on all CP...
Electroweak symmetry breaking and s-spectrum in M-theory (1999)
Kobayashi, Tatsuo, Kubo, Jisuke, Shimabukuro, Hitoshi
We study soft SUSY breaking parameters in M-theory with and without 5-brane moduli fields. We investigate successful electroweak symmetry breaking and the positivity of stau mass squared. We study...
Phenomenological constraints on SUSY SU(5) GUTs with non-universal gaugino masses (1999)
Huitu, Katri, Kawamura, Yoshiharu, Kobayashi, Tatsuo, Puolamaki, Kai
We study phenomenological aspects of supersymmetric SU(5) grand unified theories with non-universal gaugino masses. For large tan beta, we investigate constraints from the requirement of successful...
On Different Criteria for Confinement (1999)
Chaichian, Masud, Kobayashi, Tatsuo
We compare two approaches in supersymmetric confinement, the Seiberg formulation and the superconvergence rule. For the latter, the critical point is $\gamma_{00}=0$ in the Landau gauge. We find...
CP violation in a supersymmetric model with nondegenerate A terms (1999)
Khalil, Shaaban, Kobayashi, Tatsuo, Masiero, Antonio
We study the CP phases of the soft supersymmetry breaking terms in string-inspired models with non-universal trilinear couplings. We show that such non-universality plays an important role on all CP...
Running of Soft Parameters in Extra Space-Time Dimensions (1998)
Kobayashi, Tatsuo, Kubo, Jisuke, Mondragon, Myriam, Zoupanos, George
The evolution of the parameters including those in the soft supersymmetry-breaking (SSB) sector is studied in the minimal supersymmetric standard model (MSSM) with a certain set of Kaluza-Klein...
Infrared Behaviour of Softly Broken SQCD and Its Dual (1998)
Karch, Andreas, Kobayashi, Tatsuo, Kubo, Jisuke, Zoupanos, George
Applying the recently obtained results on the renormalization of soft supersymmetry-breaking parameters, we investigate the infrared behaviour of the softly broken supersymmetric QCD as well as its...
Vacuum Structure of Softly Broken N=1 Supersymmetric QCD (1998)
Chaichian, Masud, Kobayashi, Tatsuo
We study softly broken N=1 supersymmetric QCD with the gauge group $SU(N_c)$ and $N_f$ flavors of quark pairs. We investigate vacuum structure of the theory with generic soft supersymmetry breaking...
Constraints on Supersymmetric SO(10) GUTs with Sum Rules among Soft Masses (1998)
Kawamura, Yoshiharu, Kobayashi, Tatsuo, Shimabukuro, Hitoshi
We study phenomenological aspects of supersymmetric SO(10) GUTs with sum rules among soft SUSY breaking parameters. In particular, the sum rule related to the stau mass leads to the constraints from...
Softly Broken N=1 Supersymmetric QCD (1998)
Chaichian, Masud, Chen, Wen-Feng, Kobayashi, Tatsuo
We study softly broken N=1 supersymmetric QCD with the gauge group $SU(N_c)$ and $N_f$ flavours of quarks for $N_f > N_c+1$. We investigate the phase structure of its dual theory adding generic soft...
Bottom-up approach to B-parameter in minimal supersymmetric standard model (1998)
Kawamura, Yoshiharu, Kobayashi, Tatsuo, Watanabe, Manabu
We study $\mu$ and $B$-parameters in the minimal supersymmetric standard model (MSSM) based on the radiative electroweak symmetry breaking scenario using $\lq\lq$bottom-up" approach and show how...
Further all-loop results in softly-broken supersymmetric gauge theories (1998)
Kobayashi, Tatsuo, Kubo, Jisuke, Zoupanos, George
It is proven that the recently found, renormalization-group invariant sum rule for the soft scalar masses in softly-broken N=1 supersymmetric gauge-Yukawa unified theories can be extended to all...
Constraints on Finite Soft Supersymmetry-Breaking Terms (1997)
Kobayashi, Tatsuo, Kubo, Jisuke, Mondragon, Myriam, Zoupanos, George
Requiring the soft supersymmetry-breaking (SSB) parameters in finite gauge-Yukawa unified models to be finite up to and including two-loop order, we derive a two-loop sum rule for the soft...
Notes on Curtright-Zachos Deformations of osp(1,2) and Super Virasoro Algebras (1997)
Aizawa, Naruhiko, Kobayashi, Tatsuo, Sato, Haru-Tada
Based on the quantum superspace construction of $q$-deformed algebra, we discuss a supersymmetric extension of the deformed Virasoro algebra, which is a subset of the $q$-$W_{\infty}$ algebra...
Yukawa Unification in Moduli-dominant SUSY Breaking (1997)
Khalil, Shaaban, Kobayashi, Tatsuo
We study Yukawa unification in string models with moduli-dominant SUSY breaking. This type of SUSY breaking in general leads to non-universal soft masses, i.e., soft scalar masses and gaugino masses....
Probing mu-term Generation Mechanism in String Models (1997)
Kawamura, Yoshiharu, Kobayashi, Tatsuo, Watanabe, Manabu
We give a generic method to select a realistic $\mu$-term generation mechanism based on the radiative electroweak symmetry breaking scenario and study which type is hopeful within the framework of...
Soft Scalar-Mass Sum Rule in Gauge-Yukawa Unified Models and Its Superstring Interpretation (1997)
Kawamura, Yoshiharu, Kobayashi, Tatsuo, Kubo, Jisuke
It is shown that a certain sum rule for soft supersymmetry-breaking scalar masses, which has been recently found in a certain class of superstring models, is universal for gauge-Yukawa unified...
Phenomenological implications of moduli-dominant SUSY breaking (1997)
Kawamura, Yoshiharu, Khalil, Shaaban, Kobayashi, Tatsuo
We study moduli-dominated SUSY breaking within the framework of string models. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses....
Kobayashi, Tatsuo, Yoshihara, Yasuo, Samura, Atsuyoshi, Yamada, Harumoto, Shinmei, Masayuki, Roos, Harald, ...
OBJECTIVE: To explore in a cross sectional study in patients with primary knee osteoarthritis (OA) the relations between body mass index (BMI), disease stage, and the concentrations of a putative...
"Anomalous" U(1) Symmetry in Orbifold String Models (1996)
Kobayashi, Tatsuo, Nakano, Hiroaki
``Anomalous'' U(1) gauge symmetry with Green-Schwarz anomaly cancellation mechanism is discussed in the orbifold construction of four-dimensional heterotic string models. Some conditions are given as...
A String-inspired Ansatz for Quark Masses and Mixing (1996)
Kobayashi, Tatsuo, Xing, Zhi-zhong
We propose a simple but realistic pattern of quark mass matrices at the string scale, which can be derived from orbifold models of superstring theory with no use of gauge symmetries. This pattern is...
Specific Scalar Mass Relations in SU(3)*SU(2)*U(1) Orbifold Model (1996)
Kawamura, Yoshiharu, Kobayashi, Tatsuo, Komatsu, Tohru
We study flat directions and soft scalar masses using a $Z_3$ orbifold model with $SU(3) \times SU(2) \times U(1)$ gauge group and extra gauge symmetries including an anomalous $U(1)$ symmetry. Soft...
Generic Formula of Soft Scalar Masses in String Models (1996)
Kawamura, Yoshiharu, Kobayashi, Tatsuo
We derive formula of soft supersymmetry breaking scalar masses from 4-dimensional string models within a more generic framework. We consider effects of extra gauge symmetry breakings including an...
Flat Directions in $Z_{2n}$ Orbifold Models (1996)
Kawamura, Yoshiharu, Kobayashi, Tatsuo
We study generic features related to matter contents and flat directions in $Z_{2n}$ orbifold models. It is shown that $Z_{2n}$ orbifold models have massless conjugate pairs, $R$ and $\overline R$,...
Quasi Yukawa Fixed Point due to Decoupling of SUSY Particles (1996)
Kobayashi, Tatsuo, Yamagishi, Yoshio
We study effects of SUSY particle decouplings on a quasi fixed point (QFP) of Yukawa coupling. From renormalization group analysis it is shown that if the SUSY breaking scale $M_S$ is large ($\simg...
Soft Scalar Masses in String Models with Anomalous $U(1)$ symmetry (1996)
Kawamura, Yoshiharu, Kobayashi, Tatsuo
We obtain the low-energy effective theory from string models with anomalous $U(1)$ symmetry. The feature of soft supersymmetry breaking scalar masses and some phenomenological implications are...
Differential Calculi on h-deformed Bosonic and Fermionic Quantum Planes (1993)
We study differential calculus on h-deformed bosonic and fermionic quantum space. It is shown that the fermionic quantum space involves a parafermionic variable as well as a classical fermionic one....
Quantum Deformed $su(m|n)$ Algebra and Superconformal Algebra on Quantum Superspace (1993)
We study a deformed $su(m|n)$ algebra on a quantum superspace. Some interesting aspects of the deformed algebra are shown. As an application of the deformed algebra we construct a deformed...
q-deformed superconformal algebra on quantum superspace (1993)
Kobayashi, Tatsuo, Uematsu, Tsuneo
A quantum deformation of 4-dimensional superconformal algebra realized on quantum superspace is investigated. We study the differential calculus and the action of the quantum generators corresponding...
q-deformed conformal and Poincar{\'e} algebras on quantum 4-spinors (1992)
Kobayashi, Tatsuo, Uematsu, Tsuneo
We investigate quantum deformation of conformal algebras by constructing the quantum space for $sl_q(4,C)$. The differential calculus on the quantum space and the action of the quantum generators are...
Differential Calculus on the Quantum Superspace and Deformation of Phase Space (1992)
Kobayashi, Tatsuo, Uematsu, Tsuneo
We investigate non-commutative differential calculus on the supersymmetric version of quantum space where the non-commuting super-coordinates consist of bosonic as well as fermionic (Grassmann)...
The land reform in Japan. (1970)
Thesis (Ph. D. in Agricultural Economics)--Univ. of California, Dec. 1970.
OSHIMA, Shunsaku, KOBAYASHI, Tatsuo, GIMA, Yoshitake
この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。
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北海道に於ける家畜家禽寄生虫病流行状況實態調査 Ⅱ． : 北見市管内馬に就ての調査成績 (1953)
山下, 次郎, 森, 樊須, 小林, 辰雄, YAMASHITA, Jiro, MORI, Hans, KOBAYASHI, Tatsuo
Kobayashi, Tatsuo, Terao, Haruhiko
We study soft supersymmetric (SUSY) breaking parameters in the Nelson-Strassler-type models: SUSY standard models coupled with superconformal field theories (SCFT's). In this type of model, soft SUSY...
Yukawa hierarchy transfer from the superconformal sector and degenerate sfermion masses
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
We propose a new type of supersymmetric model coupled to superconformal (SC) field theories, leading simultaneously to hierarchical Yukawa couplings and completely degenerate sfermion masses. We...
Sfermion mass degeneracy, superconformal dynamics, and supersymmetric grand unified theories
Kobayashi, Tatsuo, Nakano, Hiroaki, Noguchi, Tatsuya, Terao, Haruhiko
We discuss issues in a scenario where hierarchical Yukawa couplings are generated through the strong dynamics of superconformai field theories (SCFTs). Independently of the mediation mechanism of...
Induced top-Yukawa coupling and suppressed Higgs mass parameters
Kobayashi, Tatsuo, Nakano, Hiroaki, Terao, Haruhiko
In the scenarios with heavy top squarks, mass parameters of the Higgs field must be fine-tuned due to a large logarithmic correction to the soft scalar mass. We consider a new possibility that the...
Fine-tuning in gauge mediated supersymmetry breaking models and induced top Yukawa coupling
Kobayashi, Tatsuo, Terao, Haruhiko, Tsuchiya, Akito
It is shown that fine-tuning of the Higgs parameters stronger than a few percent is required at best in the models with gauge mediated supersymmetry breaking. With the aim of solving this problem, we...
Dynamical realization of democratic Yukawa matrices and alignment of a terms
Kobayashi, Tatsuo, Omura, Yuji, Terao, Haruhiko
We study realization of the democratic form of Yukawa matrices by infrared fixed points. We investigate renormalization-group flows of Yukawa couplings in models with a single Yukawa matrix for three...
熱穿刺による發熱作用知見補遺 : 第1編 血液内Na, K, Ca, Mg含有量に及ぼす發熱の影響
Das Tierexperiment hat in den letzten Jahren Ergebnisse gefordert, welche ein neues Licht auf die Funktion der Stammganglien werfen. Schon fruher haben verschiedene Forscher darauf hingewiesen, dass...
Erschwertes Einschlafen, fruhzeitiges Aufwachen oder geringe Schlaftiefe sind Merkmale, die im echten Anwendungsgebiet der Hypnotica, wie naturlich, in Betracht genommen werden mussen. Ausserdem gilt...
Zur Erklarung der Frage des Wirkungsmechanismus und Angriffspunktes des Insulins auf die Pupille, ist noch keine bestimmte Theorie vorhanden. Jorns beobachtete die hemmende Wirkung des Insulins auf...
小林, 龍男, 高橋, 一, 室井, 正禮, Kobayashi, Tatsuo, Takahashi, Hajime, Muroi, Masamoto
Versuchsergebnisse folgen. Versuchstiere: erwachsene mittelgrosse Kaninchen bei normaler Ernahrung. Bestrahlungsstellen: Ohrmuschel, Brust, Bauch und Hinterhauptgegend. Entfernung der Solluxlampe: 3,...
小林, 龍男, 靑木, 光一, Kobayashi, Tatsuo, Aoki, Koichi
Thorn and his associates used as a criterion of adrenocortical function the fall in number of circulating eosinophils, which occur when an intact adrenal cortex is stimulated by the injection of...
It is the purpose of this paper to report on the data obtained in my laboratory during the past few years, the investigations having been directed toward the pharmacological studies on the adrenal...
熱穿刺による發熱作用知見補遺 : 第2編 体温,血壓變動機轉に及ぼす發熱の影響
Schon fruher haben verschiedene Forscher darauf hingewiesen, dass die lebenswichtige Zentren fur Warmeregulation, Blutdruck, vegetabilisches Nervensystem u. a., in den Stammganglien enthalten sind,...
熱穿刺による發熱作用知見補遺 : 第3編 家兎筋クロナキシーに及ぼす發熱の影響
In den letzten Jahren, zugleich mit dem Fortschritte der Elektrophysiologie hat die Chronaxiebestimmung nicht nur physiologische Bedeutung sondern sie findet auch als genaue Messmethode fur die...