Modern Physics Letters A

Using the effective Lagrangian method, we study the electroweak corrections to the magnetic dipole moment of muon from some special two-loop topological diagrams which are composed of chargino–sneutrino, neutralino–slepton, slepton–sneutrino, in the CP-violating minimal supersymmetric extension of the standard model. Considering the electromagnetic gauge invariance, we obtain the Wilson coefficients of those dimension 6 operators which induce the magnetic dipole moment of leptons. Adopting the zero-momentum substraction scheme, we remove the ultra-violet divergences induced by the divergent sub-diagrams. The numerical results indicate that the two-loop supersymmetric corrections from this sector to the muon magnetic dipole moment can exceed 10^-10, which is the same order of present experimental precision.

The most important open problems of the today's neutrino physics are the absolute values of the neutrino masses, the determination of the Dirac or the Majorana character and better measurements of the mixing matrix elements. Results of the neutrino oscillations experiments strongly confirm that the neutrinos have nonzero masses. Experiments give information about the differences between the squares of the masses but not any knowledge on their absolute values. Similarly neutrino oscillation phenomena does not help us to understand their Dirac or Majorana character. One of the processes that could clarify this important point is the double beta decay and the search is still going on but not yielded any positive results due to the big experimental difficulties. Also the inverse of this decay, e^-e^- → W^-W^- is another process that could be tested at the accelerators. This process is possible only if the neutrinos have masses and they are Majorana particles. Since neutrinos could have very tiny masses and the cross section of the above process is proportional to the square of the effective neutrino mass it is an extremely rare process. Also it violates total lepton number by two units, Δ = 2. In the literature the inverse neutrinoless double beta scattering have been extensively studied, in this article we obtain the relevant helicity amplitudes, investigate the effects of the neutrino mixing matrix elements, especially the roles of the CP violating phases and the possible CP asymmetries.

We explore the recent OPERA experiment of superluminal neutrinos in the framework of special relativity with de Sitter spacetime symmetry (dS-SR). According to Einstein, a photon is treated as a massless particle in the framework of special relativity. In special relativity (SR) we have the universal parameter c, the photon velocity c_photon and the phase velocity of a light wave in vacuum c_wave = λν. Due to the null experiments of Michelson–Morley we have c = c_wave. The parameter c_photon is determined by the Noether charges corresponding to the spacetime symmetries of SR. In Einstein's special relativity (E-SR) we have c = c_photon. In dS-SR, i.e. the special relativity with SO(4, 1) de Sitter spacetime symmetry, we have c_photon > c. In this paper, the OPERA datum are examined in the framework of dS-SR. We show that OPERA anomaly is in agreement with the prediction of dS-SR with R≃1.95×10¹² l.y. Based on the p-E relation of dS-SR, we also prove that the Cohen and Glashow's argument of possible superluminal neutrino's Cherenkov-like radiation is forbidden. We conclude that OPERA and ICARUS results are consistent and they are explained in the dS-SR framework.

We discuss the neutrino oscillations, using texture zero mass matrices for the leptons, including radiative correction. The neutrino mixing angle θ₁₃ is calculated and agrees with the result of the new Daya Bay experiment.

In this paper, BFT formalism of Proca model in noncommutative space is investigated. Considering that all theories with first class constraint are gauge theories, Proca model in noncommutative space is not a gauge theory in general due to the appearance of second class constraints in it. In present research, the Proca model is converted into a gauge theory using BFT approach by introducing several auxiliary variables which in turn manage to convert the second class constraints to first class ones. Consequently, we apply modified BFT that preserve the chain structure of constraints. Modified BFT has the benefit that it gives less number of independent gauge parameters and we obtain gauge generating function and infinitesimal gauge variation of fields in Proca model. As results, we investigate partition function of this model and embedded noncommutative Proca is ready to quantize in usual way.

We study the spontaneous symmetry breaking of O(3) scalar field on a fuzzy sphere . We find that the fluctuations in the background of topological configurations are finite. This is in contrast to the fluctuations around a uniform configuration which diverge, due to Mermin–Wagner–Hohenberg–Coleman theorem, leading to the decay of the condensate. Interesting implications of enhanced topological stability of the configurations are pointed out.

The N-enlarged Galilei Hopf algebra is constructed. Its twist deformations are considered and the corresponding twisted spacetimes are derived.

We briefly discuss the possible decoherence observed at the LHC emphasizing that the value of the average transverse momentum at can be interpreted as a manifestation of the deviation from the mechanism of the transient state of rotating matter.