19 papers found.

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Abstract In this paper, we study the extended Standard Model (SM) with an extra Higgs doublet and right-handed neutrinos. If the symmetry to distinguish the two Higgs doublets is not assigned, flavor changing neutral currents (FCNCs) involving the scalars are predicted even at the tree level. We investigate the constraints on the FCNCs at the one-loop level, and especially study...

We discuss effective models derived from a supersymmetric model whose mediation mechanism of supersymmetry (SUSY) breaking is namely mirage mediation. In this model, light higgsino mass, that is required by the natural realization of the electroweak scale, is achieved by the unification of the soft SUSY breaking parameters at the low scale. Besides, we find that extra Higgs...

We study dark matter physics in the Minimal Supersymmetric Standard Model with non-universal gaugino masses at the unification scale. In this scenario, the specific ratio of wino and gluino masses realizes the electro-weak scale naturally and achieves 125 GeV Higgs boson mass. Then, relatively light higgsino is predicted and the lightest neutral particle, that is dominantly given...

It is one of the major issues to realize a vacuum which breaks supersymmetry (SUSY) and R-symmetry, in a supersymmetric model. We study the model, where the same sector breaks the gauge symmetry and SUSY. In general, the SUSY breaking model without gauge symmetry has a flat direction at the minimum of F-term scalar potential. When we introduce U(1) gauge symmetry to such a SUSY...

We investigate origin of three features that are often assumed in analysis of two-Higgs doublet models: (i) softly broken Z 2 symmetry, (ii) CP invariant Higgs potential, and (iii) degenerated mass spectra. We extend electroweak gauge symmetry, introducing extra gauge symmetry and extra scalars, and we show that our models effectively derive two-Higgs doublet models at low energy...

In the scenario that dark matter (DM) is a weakly interacting massive particle, there are many possibilities of the interactions with the Standard Model (SM) particles to achieve the relic density of DM. In this paper, we consider a simple DM model where the DM candidate is a complex scalar boson. The model contains a new complex gauge singlet scalar boson and a new fermion whose...

In this paper, we investigate predictions of the SO(10) Grand Unified Theory (GUT), where an extra U(1)′ gauge symmetry remains up to the supersymmetry (SUSY) breaking scale. The minimal setup of SO(10) GUT unifies quarks and leptons into a 16-representational field in each generations. The setup, however, suffers from the realization of the realistic Yukawa couplings at the...

We discuss the 750 GeV diphoton excess at the LHC@13TeV in the framework of leptophobic U(1)′ model inspired by E 6 grand unified theory (GUT). In this model, the Standard Model (SM) chiral fermions carry charges under extra U(1)′ gauge symmetry which is spontaneously broken by a U(1)′-charged singlet scalar (Φ). In addition, extra quarks and leptons are introduced to achieve the...

We build explicit supersymmetric unification models where grand unified gauge symmetry breaking and supersymmetry (SUSY) breaking are caused by the same sector. Besides, the SM-charged particles are also predicted by the symmetry breaking sector, and they give the soft SUSY breaking terms through the so-called gauge mediation. We investigate the mass spectrums in an explicit...

In this letter, we study collider phenomenology in the supersymmetric Standard Model with a certain type of non-universal gaugino masses at the gauge coupling unification scale, motivated by the little hierarchy problem. In this scenario, especially the wino mass is relatively large compared to the gluino mass at the unification scale, and the heavy wino can relax the fine-tuning...

We study Higgs and dark matter physics in the type-II two-Higgs-doublet model (2HDM) with an extra U(1) H gauge symmetry, inspired by the E 6 grand unified theory (GUT). From the viewpoint of the bottom-up approach, the additional U(1) H gauge symmetry plays a crucial role in avoiding the tree-level flavor changing neutral currents mediated by neutral Higgs bosons in general...

A two Higgs doublet model (2HDM) is one of minimal extensions of the Standard Model (SM), and it is well-known that the general setup predicts the flavor-violating phenomena, mediated by neutral Higgs interactions. Recently the CMS collaboration has reported an excess of the lepton-flavor-violating Higgs decay in h → μτ channel with a significance of 2.4 σ. We investigate the CMS...

Flavor symmetric model is one of the attractive Beyond Standard Models (BSMs) to reveal the flavor structure of the Standard Model (SM). A lot of efforts have been put into the model building and we find many kinds of flavor symmetries and setups are able to explain the observed fermion mass matrices. In this paper, we look for common predictions of physical observables among the...

We discuss dark matter (DM) physics in the Type-I inert two-Higgs-doublet model (2HDM) with local U(1) H Higgs gauge symmetry, which is assigned to the extra Higgs doublet in order to avoid the Higgs-mediated flavor problems. In this gauged inert DM setup, a U(1) H -charged scalar Φ is also introduced to break U(1) H spontaneously through its nonzero vacuum expectation value (VEV...

It is well known that generic two-Higgs-doublet models (2HDMs) suffer from potentially large Higgs-mediated flavor-changing neutral current (FCNC) problem, unless additional symmetries are imposed on the Higgs fields thereby respecting the Natural Flavor Conservation Criterion (NFC) by Glashow and Weinberg. A common way to respect the NFC is to impose Z 2 symmetry which is softly...

We discuss semileptonic and leptonic B decays, B → D (∗) τν and B → τν, in the chiral U(1)′ models which were proposed by the present authors in the context of the top forward-backward asymmetry \( \left( {A_{\mathrm{FB}}^t} \right) \) observed at the Tevatron. In these models, extra Higgs doublets with nonzero U(1)′ charges are required in order to make the realistic mass matrix...

An extra U(1)’ model with Z’ coupled only to the right-handed (RH) up-type quarks has been one of the popular models for the Tevatron top forward-backward asymmetry (FBA), and has been excluded by the same-sign top-pair productions at the LHC. However, the original Z’ model is not physical, since the uptype quarks are massless including the top quark. This disaster can be evaded...

An extra U(1)’ model with Z’ coupled only to the right-handed (RH) up-type quarks has been one of the popular models for the Tevatron top forward-backward asymmetry (FBA), and has been excluded by the same-sign top-pair productions at the LHC. However, the original Z’ model is not physical, since the uptype quarks are massless including the top quark. This disaster can be evaded...

We revisit the discrete dark matter model with the A 4 flavor symmetry originally introduced by M.Hirsch et.al. We show that radiative corrections can lead to non-zero θ 13 and the non-zero mass for the lightest neutrino. We find an interesting relation among neutrino mixing parameters and it indicates the sizable deviation of s 23 from the maximal angle s 23 2 = 1/2 and the...