International Journal of Modern Physics A

Thanks to the latest development in the field of Monte Carlo event generators and satellite programs allowing for a straightforward implementation of any beyond the Standard Model theory in those tools, studying the property of any softly-broken supersymmetric theory is become an easy task. We illustrate this statement in the context of two nonminimal supersymmetric theories, namely the Minimal Supersymmetric Standard Model with R-parity violation and the Minimal R-symmetric Supersymmetric Standard Model and choose to probe interaction vertices involving a nonstandard color structure and the sector of the top quark. We show how to efficiently implement these theories in the MATHEMATICA package FEYNRULES and use its interfaces to Monte Carlo tools for phenomenological studies. For the latter, we employ the latest version of the MADGRAPH program.

We study the generation of μ parameter from the dynamical rearrangement of local U(1) symmetry in a five-dimensional model and discuss phenomenological implications on the θ parameter, under the assumption that supersymmetry is broken by the Scherk–Schwarz mechanism.

We reconsider in details the Dirac equation in the context of the Magueijo–Smolin approach to the Doubly Special Relativity. Starting from the deformed dispersion relation we focus on obtaining a Dirac equation in momentum space, allowing us to achieve a more in-depth study of its semiclassical approach. Finally by means of a "deformed correspondence principle" we gain access to an equation in the position space.

We present exact solutions of string cosmological models characterized by five-dimensional metrics (with four-dimensional real Lie groups as isometry groups), space independent dilaton and vanishing torsion. As an example we consider VII₀⊕R model and show that it is equivalent to the (4+1)-dimensional cosmological model coupled to perfect fluid with negative deceleration parameters (accelerating universe).

The OPERA Collaboration has announced to have observed superluminal neutrinos with a mean energy 17.5 GeV, but afterward the superluminal interpretation of the OPERA results has been refuted theoretically by Cherenkov-like radiation and pion decay. In a recent work, we have proposed a kinematical resolution to this problem. A key idea in our resolution is that the OPERA neutrinos are not superluminal but subluminal since they travel faster than the observed speed of light in vacuum on the earth while they do slower than the true speed of light in vacuum determining the causal structure of events. In this paper, we dwell upon our ideas and present some concrete models, which realize our ideas, based on spin 0, 1 and 2 bosonic fields. We also discuss that the principle of invariant speed of light in special relativity can be replaced with the principle of a universal limiting speed.

The lepton flavor violating process μ → eγ has been previously studied in a model of electroweak-scale right-handed neutrinos. We had calculated the decay amplitude in unitarity gauge [J. P. Bu, Y. Liao and J. Y. Liu, Phys. Lett. B665, 39 (2008)] and R_ξ gauge [J. P. Bu, Commun. Theor. Phys.53, 703 (2010)]. In this paper, we calculate the anomalous magnetic moment of μ in R_ξ gauge.

The symmetry breaking of five-dimensional SU(6) GUT is realized by Scherk–Schwarz mechanisms through trivial and pseudo nontrivial orbifold S¹/Z₂ breakings to produce dimensional deconstruction 5D SU(6) → 4DSU(6). The latter also induces near-brane weakly-coupled SU(6) Baby Higgs to further break the symmetry into SU(3)_C ⊗ SU(3)_H ⊗ U(1)_C. The model successfully provides a scenario of the origin of (Little) Higgs from GUT scale, produces the (intermediate and light) Higgs boson with the most preferred range and establishes coupling unification and compactification scale correctly.

In this paper, we calculate the Casimir energy for a massive fermionic field confined between two points in one spatial dimension, with the MIT bag model boundary condition. We compute the Casimir energy directly by summing over the allowed modes. The method that we use is based on the Boyer's method, and there will be no need to resort to any analytic continuation techniques. We explicitly show the graph of the Casimir energy as a function of the distance between the points and the mass of the fermionic field. We also present a rigorous derivation of the MIT bag model boundary condition.