14208084
Scalar mode analysis of the warped Salam-Sezgin model
We study the scalar perturbation sector of the general axisymmetric warped Salam-Sezgin model with codimension-2 branes. We focus on the perturbations which mix with the dilaton. We show that the scalar fluctuation analysis can be reduced to studying two scalar modes of constant wavefunction, plus modes of non-constant wavefunction which obey a single Schrödinger equation. From the obtained explicit solution of the scalar modes, we point out the importance of the non-constant modes in describing the four dimensional effective theory. This observation remains true for the unwarped case and was neglected in the relevant literature. Furthermore, we show that due to these modes, the warped solutions can be unstable for a certain region of the parameter space. ∗ e-mail address: hyun.min.lee@desy.de ∗∗ e-mail address: antonios.papazoglou@epfl.ch
119217517
U(1)R mediation from the flux compactification in six dimensions
We consider a supersymmetric completion of codimension‐two branes with nonzero tension in a 6D gauged supergravity. As a consequence, we obtain the football solution with 4D Minkowski space as a new supersymmetric background that preserves 4D N = 1 SUSY. In the presence of brane multiplets, we derive the 4D effective supergravity action for the football background and show that the remaining modulus can be stabilized by a bulk non‐perturbative correction with brane uplifting potentials at a zero vacuum energy. We find that the U(1)R mediation can be a dominant source of SUSY breaking for a brane scalar with nonzero R charge.
14096456
Wave function of the radion in the brane background with a massless scalar field and a self-tuning problem
We consider flat solutions in a brane world model with a massless scalar field appearing in 5D ${H}_{\mathrm{MNPQ}}^{2}.$ Since those solutions have naked bulk singularities or are such that the 4D Planck mass is divergent, we should have a compact extra dimension, the size of which is then fixed by brane tension(s) and the bulk cosmological constant. By inspecting scalar perturbations around the flat solutions, we find that there is no zero mode for the radion and radion modes have only positive masses. This result confirms the fact that the radius of the extra dimension cannot be adjusted independently of the parameters of the model, and thus that the model considered does not solve the problems encountered in other approaches to the self-tuning of the cosmological constant.
14725085
Various modified solutions of the Randall–Sundrum model with the Gauss–Bonnet interaction
Abstract The Gauss–Bonnet interaction is the only consistent quadratic interaction below the Planck scale in the Randall–Sundrum compactification. We study various static and inflationary solutions including this Gauss–Bonnet interaction.
11210523
TeV scale 5D SU(3)W unification and the fixed point anomaly cancellation with chiral split multiplets
A possibility of 5D gauge unification of SU(2)L × U(1)Y in SU(3)W is examined. The orbifold compactification allows fixed points where SU(2)L × U(1)Y representations can be assigned. We present a few possibilities which give long proton lifetime, top-bottom mass hierarchy from geometry, and reasonable neutrino masses. In general, these chiral models can lead to fixed point anomalies. We can show easily, due to the simplicity of the model, that these anomalies are cancelled by the relevant Chern-Simons terms for all the models we consider. It is also shown that the fixed point U(1)-graviton-graviton anomaly cancels without the help from the Chern-Simons term. Hence, we conjecture that the fixed point anomalies can be cancelled if the effective 4D theory is made anomaly free by locating chiral fermions at the fixed points.
119248157
Vector Higgs-portal dark matter and the invisible Higgs
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak
21933383
Fourth generation parity.
We present a very simple fourth generation (4G) model with an abelian gauge interaction under which only the 4G fermions have nonzero charge. The U(1) gauge symmetry can have a Z2 residual discrete symmetry (4G parity), which can stabilize the lightest 4G particle (L4P). When the 4G neutrino is the L4P, it would be a neutral and stable particle and the other 4G fermions would decay into the L4P, leaving the trace of missing energy plus the standard model fermions. Because of the new symmetry, the 4G particle creation and decay modes are different from those of the sequential 4G model, and the 4G particles can be appreciably lighter than typical experimental bounds.
9421064
Characteristics of QCD phase transitions in an extended Skyrme model on S**3
We study the characteristics of the QCD phase transitions in dense hadronic matter using the Skyrme model constructed on S^3. We find numerically the localized solutions on $S^3$ using the extended Skyrme model which implements correctly the scale symmetry of QCD. The transition from the localized phase to the delocalized phase is found to be of first order at the critical radius of the hypersphere, $L_c$. The chiral restoration and the gluon decondensation also take place at the same critical size.
14087471
Generalized lepton number and dark left-right gauge model
In a left-right gauge model of particle interactions, the left-handed fermion doublet $(\ensuremath{\nu},e{)}_{L}$ is connected to its right-handed counterpart $(n,e{)}_{R}$ through a scalar bidoublet so that ${e}_{L}$ pairs with ${e}_{R}$, and ${\ensuremath{\nu}}_{L}$ with ${n}_{R}$ to form mass terms. Suppose the latter link is severed without affecting the former, then ${n}_{R}$ is not the mass partner of ${\ensuremath{\nu}}_{L}$, and as we show in this paper, becomes a candidate for dark matter which is relevant for the recent PAMELA and ATIC observations. We accomplish this in a specific nonsupersymmetric model, where a generalized lepton number can be defined, so that ${n}_{R}$ and ${W}_{R}^{\ifmmode\pm\else\textpm\fi{}}$ are odd under $R\ensuremath{\equiv}(\ensuremath{-}1{)}^{3B+L+2j}$. Fermionic leptoquarks are also predicted.
119238978
Minimal gauge origin of baryon triality and flavorful signatures at the LHC
Abstract Baryon triality ( B 3 ) is a Z 3 discrete symmetry that can protect the proton from decay. Although its realization does not require supersymmetry, it is particularly appealing in the supersymmetry as an alternative to the popular R-parity. We discuss the issues in gauging B 3 , and present the minimal supersymmetric model with B 3 as the remnant discrete symmetry of a TeV scale U ( 1 ) gauge symmetry. A flavor-dependent U ( 1 ) charge is necessary to achieve this, and it results in very distinguishable and flavorful predictions for the LHC experiments. We find a complementarity between a 2-lepton sneutrino resonance and a 4-lepton Z ′ resonance in the supersymmetry search when a certain condition is satisfied. In addition, we introduce baryon tetrality ( B 4 ), which would play an equivalent role if there are four fermion generations.
118692473
“Dark” Z implications for parity violation, rare meson decays, and Higgs physics
General consequences of mass mixing between the ordinary Z boson and a relatively light Z_d boson, the "dark" Z, arising from a U(1)_d gauge symmetry, associated with a hidden sector such as dark matter, are examined. New effects beyond kinetic mixing are emphasized. Z-Z_d mixing introduces a new source of low energy parity violation well explored by possible future atomic parity violation and planned polarized electron scattering experiments. Rare K (B) meson decays into pi (K) l^+ l^- (l = e, mu) and pi (K) nu anti-nu are found to already place tight constraints on the size of Z-Z_d mixing. Those sensitivities can be further improved with future dedicated searches at K and B factories as well as binned studies of existing data. Z-Z_d mixing can also lead to the Higgs decay H -> Z Z_d, followed by Z -> l_1^+ l_1^- and Z_d -> l_2^+ l_2^- or "missing energy", providing a potential hidden sector discovery channel at the LHC. An illustrative realization of these effects in a 2 Higgs doublet model is presented.