arXiv subjects

Nobuhito Maru

Publications and source records attributed to Nobuhito Maru.

At least 127 records · Page 7Linked to original sources

arXiv2002

Exactly solved BPS wall and winding number in N=1 Supergravity

A BPS exact wall solution is found in N=1 supergravity in four dimensions. The model uses chiral scalar field with a periodic superpotential admitting winding numbers. Maintaining the periodicity in supergravity requires a gravitational correction to superpotential which allows the exact solution. By introducing boundary cosmological constants, we construct non-BPS multi-wall solutions for which a systematic analytic approximation is worked out for small gravitational coupling.

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arXiv2002

(S)fermion Masses in Fat Brane Scenario

We discuss the fermion mass hierarchy and the flavor mixings in the fat brane scenario of a five dimensional SUSY theory. Assuming that the matter fields lives in the bulk, their zero mode wave functions are Gaussians, and Higgs fields are localized on the brane, we find simple various types of the matter configurations generating the mass matrices consistent with experimental data. Sfermion mass spectrum is also discussed using the matter configurations found above. Which type of squark mass spectra (the degeneracy, the decoupling and the alignment) is realized depends on the relative locations of SUSY breaking brane and the brane where Higgs fields are localized.

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arXiv2002

Light Higgs Triplets in Extra Dimensions

We discuss the possibility that the Higgs triplet can be light (1TeV in the most interesting case) without contradictions with the proton stability %and the gauge coupling unification in the context of higher dimensional theory. The proton stability is ensured by the suppression of Yukawa coupling of the Higgs triplet to the matter through its small overlap of wave functions in extra dimensions. The light Higgs triplets might be detected in future collider experiments as an alternative signature of GUT instead of the proton decay. The gauge coupling unification can be preserved by introducing extra bulk matter fields.

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arXiv2002

Decoupling Solution to SUSY Flavor Problem via Extra Dimensions

We discuss the decoupling solution to SUSY flavor problem in the fat brane scenario. We present a simple model to yield the decoupling sfermion spectrum in a five dimensional theory. Sfermion masses are generated by the overlap between the wave functions of the matter fields and the chiral superfields on the SUSY breaking brane. Two explicit examples of the spectrum are given.

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arXiv2001

SUSY Breaking by stable non-BPS configurations

A simple mechanism for SUSY breaking is proposed due to the coexistence of BPS domain walls. It requires no messenger fields nor complicated SUSY breaking sector on any of the walls. We assumed that our world is on a BPS domain wall and that the other BPS wall breaks the SUSY preserved by our wall. We obtain an ${\cal N}=1$ model in four dimensions which admits an exact solution of a stable non-BPS configuration of two walls. The stability is assured by a topological quantum number associated with the winding on the field space of the topology of $S^1$. We propose that the overlap of the wave functions of the Nambu-Goldstone fermion and those of physical fields provides a practical method to evaluate SUSY breaking mass splitting on our wall thanks to a low-energy theorem. This is based on our recent works hep-th/0009023 and hep-th/0107204.

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arXiv2001

Doublet-Triplet Splitting and Fat Branes

We consider the doublet-triplet splitting problem in supersymmetric SU(5) grand unified theory in five dimensions where the fifth dimension is non-compact. We point out that an unnatural fine-tuning of parameters in order to obtain the light Higgs doublets is not required due to the exponential suppression of the overlap of the wave functions.

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arXiv2001

Simple SUSY Breaking Mechanism by Coexisting Walls

A SUSY breaking mechanism with no messenger fields is proposed. We assume that our world is on a domain wall and SUSY is broken only by the coexistence of another wall with some distance from our wall. We find an ${\cal N}=1$ model in four dimensions which admits an exact solution of a stable non-BPS configuration of two walls and studied its properties explicitly. We work out how various soft SUSY breaking terms can arise in our framework. Phenomenological implications are briefly discussed. We also find that effective SUSY breaking scale becomes exponentially small as the distance between two walls grows.

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arXiv2001

SUSY Breaking by Stable non-BPS Walls

A new simple mechanism for SUSY breaking is proposed due to the coexistence of BPS domain walls. It is assumed that our world is on a BPS domain wall and that the other BPS wall breaks the SUSY preserved by our wall. This mechanism requires no messenger fields nor complicated SUSY breaking sector on any of the walls. We obtain an ${\cal N}=1$ model in four dimensions which has an exact solution of a stable non-BPS configuration of two walls. We propose that the overlap of the wave functions of the N-G fermion and those of physical fields provides a practical method to evaluate SUSY breaking mass splitting on our wall thanks to a low-energy theorem. This is based on our recent works hep-th/0009023 and hep-th/0107204.

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arXiv2001

SUSY Breaking by Coexisting Walls

Supersymmetry (SUSY) breaking without messenger fields is proposed. We assume that our world is on a wall and SUSY is broken only by the coexistence of another wall with some distance from our wall. The Nambu-Goldstone (NG) fermion is localized on the distant wall. Its overlap with the wave functions of physical fields on our wall gives the mass splitting of physical fields on our wall thanks to a low-energy theorem. We propose that this overlap provides a practical method to evaluate mass splitting in models with SUSY breaking due to the coexistence of walls.

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arXiv2001

Nonanomalous R-symmetry in supersymmetric unified theories of quarks and leptons

A discrete R-symmetry often appears as an exact gauge symmetry in the low energy effective theory of superstring theories. We search for such discrete R-symmetries from a phenomenological point of view and find that Z_{9R} and Z_{18R} are candidates of the nonanomalous R-symmetry in the case of the minimal supersymmetric standard model. We also find Z_{4R} and Z_{20R} in the case that quarks and leptons are embedded in the SU(5) GUT multiplets. Interesting is that in the latter case all the solutions predict some extra matter multiplets and we find that the simplest choice is to take a pair of {\bf 5} and {\bf 5}^* of SU(5)_{GUT} whose mass is of order the SUSY breaking scale \sim 1 TeV. We emphasize that the presence of such extra matters is testable in future collider experiments.

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arXiv2000

SUSY Breaking by Overlap of Wave Functions in Coexisting Walls

SUSY breaking without messenger fields is proposed. We assume that our world is on a wall and SUSY is broken only by the coexistence of another wall with some distance from our wall. The Nambu-Goldstone fermion is localized on the distant wall. Its overlap with the wave functions of physical fields on our wall gives the mass splitting of physical fields on our wall thanks to a low-energy theorem. We propose that this overlap provides a practical method to evaluate mass splitting in models with SUSY breaking due to the coexisting walls.

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arXiv2000

R-mediation of Dynamical Supersymmetry Breaking

We propose a simple scenario of the dynamical supersymmetry breaking in four dimensional supergravity theories. The supersymmetry breaking sector is assumed to be completely separated as a sequestered sector from the visible sector, except for the communication by the gravity and U(1)_R gauge interactions, and the supersymmetry breaking is mediated by the superconformal anomaly and U(1)_R gauge interaction. Supersymmetry is dynamically broken by the interplay between the non-perturbative effect of the gauge interaction and Fayet-Iliopoulos D-term of U(1)_R which necessarily exists in supergravity theories with gauged U(1)_R symmetry. We construct an explicit model which gives phenomenologically acceptable mass spectrum of superpartners with vanishing (or very small) cosmological constant.

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arXiv2000

Dynamical Supersymmetry Breaking with Gauged U(1)_R Symmetry

We propose a simple model of dynamical supersymmetry breaking in the context of minimal supergravity with gauged $U(1)_R$ symmetry. The model is based on the gauge group $SU(2) \times U(1)_R$ with three matters. Since the $U(1)_R$ symmetry is gauged, the Fayet-Iliopoulos D-term appears due to the symmetry of supergravity. On the other hand, the superpotential generated dynamically by the SU(2) gauge dynamics leads to run away potential. Since the supersymmetric vacuum condition required by the D-term potential contradicts the one required by the superpotential, supersymmetry is broken. The supersymmetry breaking scale is controlled by the dynamical scale of the SU(2) gauge interaction. We can choose the parameters in our model for vanishing cosmological constant. Our model is phenomenologically viable with the gravitino mass of order 1 TeV or 10 TeV.

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arXiv2000

Models of Dynamical Supersymmetry Breaking with Gauged $U(1)_R$ Symmetry

We present simple models of dynamical supersymmetry breaking with gauged U(1)_R symmetry. The minimal supersymmetric standard model and supersymmetric SU(5) GUT are considered as the visible sector. The anomaly cancellation conditions for U(1)_R are investigated in detail and simple solutions of the R-charge assignments are found. We show that this scenario of dynamical supersymmetry breaking is phenomenologically viable with the gravitino mass of order 1 TeV or 10 TeV.

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arXiv1999

Dual Description for SUSY SO(N) Gauge Theory with a Symmetric Tensor

We consider \caln=1 supersymmetric SO(N) gauge theory with a symmetric traceless tensor. This theory saturates 't Hooft matching conditions at the origin of the moduli space. This naively suggests a confining phase, but Brodie, Cho, and Intriligator have conjectured that the origin of the moduli space is in a Non-Abelian Coulomb phase. We construct a dual description by the deconfinement method, and also show that the theory indeed has an infrared fixed point for certain values of N. This result supports their argument.

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arXiv1998

A New Model of Direct Gauge Mediation with an Affine Quantum Moduli Space

We present a new, simple supersymmetry breaking model with direct gauge mediation. Supersymmetry breaking sector is based on the model with an Affine quantum moduli space. The model has no gauge messengers and no light scalars charged under the Standard Model which give a negative contribution to the soft masses. Large expectation value at the minimum is obtained by balancing the runaway potential and the dimension six nonrenormalizable term. This makes it easy to preserve the perturbative unification. Enough suppression of the supergravity contribution to the soft masses can also be shown.

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arXiv1998

Matrix String Theory from Brane Configuration

Configurations of fivebranes, twobranes and fourbranes in type IIA string theory, which give (1+1) dimensional supersymmetric gauge theories in the low energy limit, are constructed. It is shown that these brane configurations are equivalent to a certain class of matrix string theories. This opens up an avenue for the investigation of matrix string dynamics via the geometry of the brane configurations in type IIA string theory.

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arXiv1998

Confining phase in SUSY SO(12) gauge theory with one spinor and several vectors

We study the confining phase structure on {\cal N}=1 supersymmetric SO(12) gauge theory with N_f \le 7 vectors and one spinor. The explicit form of low energy superpotentials for N_f \le 7 are derived after gauge invariant operators relevant in the effective theory are identified via gauge symmetry breaking pattern. The resulting confining phase structure is analogous to N_f \le N_c+1 SUSY QCD. Finally, we conclude with some comments on the search for duals to N_f \ge 8 SO(12) theory.

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