16283086
Three generation magnetized orbifold models
Abstract 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 flux. We classify the flavor structures and show possible patterns of Yukawa matrices. Some examples of numerical studies are also shown.
15756286
Non-Abelian discrete flavor symmetries from magnetized/intersecting brane models
Abstract We study non-Abelian discrete flavor symmetries, which appear in magnetized brane models. For example, D 4 , Δ ( 27 ) and Δ ( 54 ) flavor symmetries can appear with matter fields in several representations. We also study the orbifold background, where non-Abelian flavor symmetries are broken in a certain way.
119200217
Towards the MSSM from F-theory
Abstract We study the MSSM in F-theory. Its group is the commutant to a structure group SU ( 5 ) × U ( 1 ) Y of a gauge bundle in E 8 . The spectrum contains three generations of quarks and leptons plus vectorlike electroweak and colored Higgses. The minimal MSSM Yukawa couplings with matter parity is obtained at the renormalizable level.
118237829
UV Completion of Axion
A multiple number of global U(1)s, arising from accidental symmetries up to a certain order of the potential, enjoy lowering the axion decay constant from UV‐scale and evading supersymmetric Fayet–Illiopoulos term constraints.
119201914
Extended gauge symmetries in F-theory
We study gauge symmetry in F-theory in light of global aspects. For this, we consider not only a simple (local) group, but also a semi-simple group with Abelian factors. Once we specify the complete gauge group by decomposing the discriminant, analogous to arranging 7-branes, we can derive the matter contents, their localization and the relation to enhanced groups. Global constraints coming from Calabi-Yau conditions and anomaly cancellations imply a unified group. The semisiple group shows explicit formation of matter curves and nontriviality of its embedding into exceptional group. Also the dual heterotic string vacua with line bundles provide a guide on the unification.
119243457
Non-Abelian Discrete Flavor Symmetries on Orbifolds
We study non-Abelian flavor symmetries on orbifolds, S1/Z2 and T2/Z3. Our extra dimensional models realize DN, Σ(2N2), Δ(3N2) and Δ(6N2) including A4 and S4. In addition, one can also realize their subgroups such as QN, T7, etc. The S3 flavor symmetry can be realized on both S1/Z2 and T2/Z3 orbifolds.
54193494
Sparticle spectrum of large volume compactification
We examine the large volume compactification of Type IIB string theory or its F theory limit and the associated supersymmetry breakdown and soft terms. It is crucial to incorporate the loop-induced moduli mixing, originating from radiative corrections to the Kähler potential. We show that in the presence of moduli mixing, soft scalar masses generically receive a D-term contribution of the order of the gravitino mass m3/2 when the visible sector cycle is stabilized by the D-term potential of an anomalous U(1) gauge symmetry, while the moduli-mediated gaugino masses and A-parameters tend to be of the order of m3/2/8π2. It is noticed also that a too large moduli mixing can destabilize the large volume solution by making it a saddle point.
119256844
Effective interactions of axion supermultiplet and thermal production of axino dark matter
We discuss the effective interactions of axion supermultiplet, which might be important for analyzing the cosmological aspect of supersymmetric axion model. Related to axino cosmology, it is stressed that three seemingly similar but basically different quantities, the Wilsonian axino-gluino-gluon coupling, the 1PI axino-gluino-gluon amplitude, and the PQ anomaly coefficient, should be carefully distinguished from each other for correct analysis of the thermal production of axinos in the early Universe. It is then noticed that the 1PI axino-gluino-gluon amplitude at energy scale p in the range MΦ < p < vPQ is suppressed by MΦ2/p2 in addition to the well-known suppression by p/16π2vPQ, where MΦ is the mass of the heaviest PQ-charged and gauge-charged matter supermultiplet in the model, which can be well below the PQ scale vPQ. As a result, axino production at temperature T > MΦ is dominated by the production by matter supermultiplet, not by the production by gauge supermultiplet. Still the axino production rate is greatly reduced if MΦ ≪ vPQ, which would make the subsequent cosmology significantly altered. This would be most notable in the supersymmetric DFSZ model in which MΦ corresponds to the Higgsino mass which is around the weak scale, however a similar reduction is possible in the KSVZ model also. We evaluate the relic axino density for both the DFSZ and KSVZ models while including the axino production in the processes involving the heaviest PQ-charged and gauge-charged matter supermultiplet.
119181837
Axial charges of the nucleon and N* resonances
The axial charges of the nucleon and the well-established N * resonances are studied within a consistent framework. For the first time the axial charges of the N * resonances are produced for the relativistic constituent quark model. The axial charge of the nucleon is predicted close to experiment, and the ones of N * (1535) and N * (1650), the only cases where such a comparison is possible, agree well with results from quantum chromodynamics on the lattice that have recently become available. The relevance of the magnitudes of the N * axial charges for the low-energy behavior of quantum chromodynamics is discussed.
14862395
Softness of brane-localized supersymmetry breaking on orbifolds
Abstract We consider the brane-localized supersymmetry breaking in 5D compactified on S 1 / Z 2 . In case of a bulk gaugino with arbitrary brane masses for its even and odd modes, we find the mass spectrum and the wave functions of gaugino. We show that the gaugino masses at the distant brane are soft in the usual sense in the effective field theory with zero modes of bulk gauge fields and they are also extremely soft in view of the one-loop finite mass of a brane scalar in the KK regularization.
118521026
Large non-Gaussianity from two-component hybrid inflation
We study the generation of non-Gaussianity in models of hybrid inflation with two inflaton fields, (2-brid inflation). We analyse the region in the parameter and the initial condition space where a large non-Gaussianity may be generated during slow-roll inflation which is generally characterised by a large fNL, τNL and a small gNL. For certain parameter values we can satisfy τNL >> fNL2. The bispectrum is of the local type but may have a significant scale dependence. We show that the loop corrections to the power spectrum and bispectrum are suppressed during inflation, if one assume that the fields follow a classical background trajectory. We also include the effect of the waterfall field, which can lead to a significant change in the observables after the waterfall field is destabilised, depending on the couplings between the waterfall and inflaton fields.