Nobuhito Maru

Osaka City University, Ōsaka, Ōsaka, Japan

Are you Nobuhito Maru?

Claim your profile

Publications (16)39.89 Total impact

  • Source
    H. Itoyama, Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We present an extension of the mass sum rule that applies to renormalizable rigid supersymmetric field theories to the case of the N=1 supersymmetric effective action (the gauged non-linear sigma model) consisting of adjoint scalar superfields and vector superfields possessing a K"ahler potential, a set of gauge coupling functions (second prepotential derivatives) and a superpotential, which respectively set their energy scales. The mass sum rule derived is valid for any vacua, including the (metastable) one of broken supersymmetry with the condensates of D-term and/or F-term. We manage to extend these analyses to the cases where superfields in (anti-)fundamental representation are present. The supertrace is shown to vanish in those cases where underlying geometry is special K"ahler and theory under concern is anomaly free. Simple phenomenological application is given, providing an upper bound for gaugino masses. We discuss that the effects of the D and/or F condensates can be represented as a set of soft breaking terms with their strengths predicted by the scales.
  • Source
    Hiroshi Itoyama, Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: Continuing with our previous work on D-term triggered dynamical supersymmetry breaking, we consider a system in which our generic N=1 action is minimally extended to include the pair of Higgs doublet superfields charged under the overall U(1) as well as mu and B mu terms. The gauge group is taken to be SU(3)_C times SU(2)_L times U(1)_Y times U(1). We point out, among other things, that the Higgs mass less than the Z-boson mass at tree level can be pushed up to be around 126 GeV by D-term contributions of the overall U(1). This is readily realized by taking a U(1) gauge coupling of O(1).
    Symmetry 12/2013; 7(1). DOI:10.3390/sym7010193 · 0.92 Impact Factor
  • Source
    H. Itoyama, Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We present the mechanism of the dynamical supersymmetry breaking at the metastable vacuum recently uncovered in the N=1 U(N) supersymmetric gauge theory that contains adjoint superfields and that is specified by Kahler and non-canonical gauge kinetic functions and a superpotential whose tree vacua preserve N=1 supersymmetry. The overall U(1) serves as the hidden sector and no messenger superfield is required. The dynamical supersymmetry breaking is triggered by the non-vanishing D term coupled to the observable sector, and is realized by the self-consistent Hartree-Fock approximation of the NJL type while it eventually brings us the non-vanishing F term as well. It is shown that theoretical analysis is resolved as a variational problem of the effective potential for three kinds of background fields, namely, the complex scalar, and the two order parameters D and F of supersymmetry, the last one being treated perturbatively. We determine the stationary point and numerically check the consistency of such treatment as well as the local stability of the scalar potential. The coupling to the N = 1 supergravity is given and the gravitino mass formula is derived.
    Physical Review D 01/2013; 88(2). DOI:10.1103/PhysRevD.88.025012 · 4.86 Impact Factor
  • Source
    Hiroshi Itoyama, Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider an N=1 supersymmetric U(N) gauge theory with an adjoint chiral multiplet. By developing a self-consistent Hartree-Fock approximation to the leading order which is reminiscent of that of the BCS/NJL in the superconductivity/chiral symmetry, we show that the N=1 supersymmetry is spontaneously broken, giving a mixed Majorana-Dirac mass term for gaugino due to the nonvanishing D-term VEV and F-term one induced by D-term.
    07/2012; DOI:10.1142/S2010194513009392
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Gauge-Higgs unification is the fascinating scenario solving the hierarchy problem without supersymmetry. In this scenario, the Standard Model (SM) Higgs doublet is identified with extra component of the gauge field in higher dimensions and its mass becomes finite and stable under quantum corrections due to the higher dimensional gauge symmetry. On the other hand, Yukawa coupling is provided by the gauge coupling, which seems to mean that the flavor mixing and CP violation do not arise at it stands. In this talk, we discuss that the flavor mixing is originated from simultaneously non-diagonalizable bulk and brane mass matrices. Then, this mechanism is applied to various flavor changing neutral current (FCNC) processes via Kaluza-Klein (KK) gauge boson exchange at tree level and constraints for compactification scale are obtained.
    04/2012; 1467(1). DOI:10.1063/1.4742112
  • Source
    Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We propose a new chiral model of metastable supersymmetry breaking in the conformal window via chiral/nonchiral Seiberg duality, which is focused on Spin(7)/SU(N_f-4) duality in this letter. Following the approach of Intriligator-Seiberg-Shih model, a small mass perturbation in the nonchiral theory leads to supersymmetry breaking by rank condition in the chiral dual description.
  • Source
    Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We propose a direct gauge mediation model based on an uplifted metastable SUSY breaking coupled to supergravity. A constant superpotential plays an essential role to fix the moduli as well as breaking SUSY and R-symmetry and the cancellation of the cosmological constant. Gaugino masses are generated at leading order of SUSY breaking scale, and comparable to the sfermion masses as in the ordinary gauge mediation. Landau pole problem for QCD coupling can be easily solved since more than half of messengers become superheavy, which are heavier than the GUT scale. Comment: 14 pages, 2 figures, references added
    Physical review D: Particles and fields 08/2010; 82(7). DOI:10.1103/PHYSREVD.82.075015 · 4.86 Impact Factor
  • Source
    C. S. Lim, Nobuhito Maru, Kenji Nishiwaki
    [Show abstract] [Hide abstract]
    ABSTRACT: We address the challenging issue of how CP violation is realized in higher dimensional gauge theories without higher dimensional elementary scalar fields. In such theories interactions are basically governed by a gauge principle and therefore to get CP violating phases is a non-trivial task. It is demonstrated that CP violation is achieved as the result of compactification of extra dimensions, which is incompatible with the 4-dimensional CP transformation. As a simple example we adopt a 6-dimensional U(1) model compactified on a 2-dimensional orbifold $T^{2}/Z_{4}$. We argue that the 4-dimensional CP transformation is related to the complex structure of the extra space and show how the $Z_{4}$ orbifolding leads to CP violation. We confirm by explicit calculation of the interaction vertices that CP violating phases remain even after the re-phasing of relevant fields. For completeness, we derive a re-phasing invariant CP violating quantity, following a similar argument in the Kobayashi-Maskawa model which led to the Jarlskog parameter. As an example of a CP violating observable we briefly comment on the electric dipole moment of the electron. Comment: 22 pages, 6 figures, Final version to appear in PRD
    Physical review D: Particles and fields 10/2009; 81(7). DOI:10.1103/PhysRevD.81.076006 · 4.86 Impact Factor
  • Source
    Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: In this talk, we discuss an attempt to construct a realistic model of the grand gauge-Higgs unification. We investigate a 5D SU(6) grand gauge-Higgs unification model compactified on an orbifold S^1/Z_2. Ordinary quarks and leptons, together with right-handed neutrinos, are just accommodated into a minimal set of representations of the gauge group, without introducing any exotic states in the same representations. The proton decay turns out to be forbidden at least at the tree level. We also find a correct electroweak symmetry breaking SU(2)_L \times U(1)_Y \to U(1)_{em} is easily realized by introducing suitable number of adjoint fermions.
    03/2008; DOI:10.1063/1.2939048
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The zero mode of an extra-dimensional component of gauge potentials serves as a 4D Higgs field in the gauge-Higgs unification. We examine QED on $M^4 \times S^1$ and determine the mass and potential of a 4D Higgs field (the $A_5$ component) at the two loop level with gauge invariant reguralization. It is seen that the mass is free from divergences and independent of the renormalization scheme.
    Progress of Theoretical Physics 10/2007; DOI:10.1143/PTP.118.1053 · 2.06 Impact Factor
  • Source
    Nobuhito Maru, Toshifumi Yamashita
    [Show abstract] [Hide abstract]
    ABSTRACT: We calculate the quantum corrections to the mass of the zero mode of the fifth component of the gauge field at two-loop level in a five-dimensional massless QED compactified on S1. We discuss in detail how the divergences are exactly canceled and the mass becomes finite. The key ingredients to obtain the result are the shift symmetry and the Ward–Takahashi identity. We also evaluate the finite part of corrections.
    Nuclear Physics B 10/2006; DOI:10.1016/j.nuclphysb.2006.07.023 · 3.95 Impact Factor
  • Source
    C. S. Lim, Nobuhito Maru, K. Hasegawa
    [Show abstract] [Hide abstract]
    ABSTRACT: We calculate one-loop radiative correction to the mass of Higgs identified with the extra space components of the gauge field in a six dimensional massive scalar QED compactified on a two-sphere. The radiatively induced Higgs mass is explicitly shown to be finite for arbitrary bulk scalar mass M. Furthermore, the remaining finite part also turns out to vanish, at least for the case of small M, thus suggesting that the radiatively induced Higgs mass exactly vanishes, in general. The non-zero "Kaluza-Klein" modes in the gauge sector are argued to have a Higgs-like mechanism and quantum mechanical N=2 supersymmetry, while the Higgs zero modes, as supersymmetric states, have a close relation with monopole configuration.
    Journal of the Physical Society of Japan 06/2006; 77(7). DOI:10.1143/JPSJ.77.074101 · 1.48 Impact Factor
  • Source
    Koichi Hamaguchi, Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: We discuss nonanomalous R-symmetry in the supersymmetric grand unified theories. In particular, we explore anomaly-free solutions predicting the gravitino mass in the range of $10^{-3} eV \lsim m_{3/2} \lsim 1 TeV$ when the $\mu$-parameter is fixed to be $\mu \simeq 1 TeV$. In the minimal SU(5) GUT, we have shown that $\mu \simeq 1 TeV$ is obtained only if the gravitino is ultralight with mass $m_{3/2} \sim 10^{-3} eV$. If extra fields ${\bf 5}\oplus{\bf 5^*}$ or ${\bf 10}\oplus{\bf 10^*}$ are introduced, many solutions predicting $m_{3/2} \gsim 10^{-3} eV$ are found. The R-parity is violated due to the vacuum expectation value of the superpotential, but it is controlled by the discrete R-symmetry. We find that the R-parity violating couplings are naturally suppressed much below the experimental bounds for some charge assignments. These charge assignments predict light gravitino with masses of order ${\cal O}(10^{-3} eV)$--${\cal O}(1 MeV)$. These discrete R-symmetries can be considered as solutions to the $\mu$-problem in low energy supersymmetry breaking models such as the gauge mediation. Comment: 20 pages, no figure. v2: minor corrections, references added, "Note Added" in Summary added
    Physical Review D 02/2003; 67(11). DOI:10.1103/PhysRevD.67.115003 · 4.86 Impact Factor
  • Source
    Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: 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. Comment: 10 pages, LaTeX, no figures, the version to appear in Phys. Lett. B
    Physics Letters B 08/2001; 522(1-2). DOI:10.1016/S0370-2693(01)01276-X · 6.02 Impact Factor
  • Source
    Kiichi Kurosawa, Nobuhito Maru, T. Yanagida
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 Z9R and Z18R are candidates of the nonanomalous R-symmetry in the case of the minimal supersymmetric standard model. We also find Z4R and Z20R 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 of the extra matters is to take a pair of and of SU(5)GUT whose mass is of order the SUSY breaking scale ∼1 TeV. We emphasize that the presence of such extra matters is testable in future hadron collider experiments.
    Physics Letters B 07/2001; DOI:10.1016/S0370-2693(01)00699-2 · 6.02 Impact Factor
  • Source
    Nobuhito Maru
    [Show abstract] [Hide abstract]
    ABSTRACT: 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.

Publication Stats

233 Citations
39.89 Total Impact Points

Institutions

  • 2014
    • Osaka City University
      • Graduate School of Science
      Ōsaka, Ōsaka, Japan
  • 2013
    • Keio University
      • Research and Education Center for Natural Sciences
      Edo, Tōkyō, Japan
  • 2009–2010
    • Chuo University
      • Department of Physics
      Tokyo, Tokyo-to, Japan
  • 2006
    • Sapienza University of Rome
      • Department of Physics
      Roma, Latium, Italy
  • 2001–2003
    • The University of Tokyo
      • Department of Physics
      Tokyo, Tokyo-to, Japan