Modern Physics Letters A

We review the prospects of direct spin determination of new particles which may be discovered at the LHC. We discuss the general framework and the different channels which contain spin information. The experimental challenges associated with such measurements are briefly discussed and the most urgent unresolved problems are emphasized.

Starting from an supersymmetric electric gauge theory with the gauge group Sp(N_c) × SO(2N′_c) with fundamentals for the first gauge group factor and a bifundamental, we apply Seiberg dual to the symplectic gauge group only and arrive at the supersymmetric dual magnetic gauge theory with dual matters including the gauge singlets and superpotential. By analyzing the F-term equations of the dual magnetic superpotential, we describe the intersecting brane configuration of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of this gauge theory.

In the effective theory for the deconfining phase of SU(2) Yang–Mills thermodynamics we compute estimates for the moduli of the irreducible three-loop diagrams contributing to the pressure. Our numerical results are in agreement with general expectations.

The contributions of scalar and gauge leptoquarks into widths of , B⁰→e^∓τ^± decays are calculated in the models with the vectorlike and chiral four-color symmetry and with the Higgs mechanism of the quark–lepton mass splitting. From the current data on and B⁰ decays the mass limits for scalar and chiral leptoquarks and the updated vector leptoquark mass limits are obtained. It is shown that unlike the gauge leptoquarks the scalar leptoquark mass limits are weak, of order or below their direct mass limits. The search for such scalar leptoquarks at LHC and the further search for leptonic decays are of interest.

We have studied the self-adjointness of generalized MIC–Kepler Hamiltonian, obtained from the formally self-adjoint generalized MIC–Kepler Hamiltonian. We have shown that for , the system admits a one-parameter family of self-adjoint extensions and for but , it also has a one-parameter family of self-adjoint extensions.

We study the topological defects in the nonlinear O(3) sigma model in terms of the decomposition of U(1) gauge potential. Time-dependent baby skyrmions are discussed in the (2+1)-dimensional spacetime with the CP¹ field. Furthermore, we show that there are three kinds of topological defects–vortex lines, point defects and knot exist in the (3+1)-dimensional model, and their topological charges, locations and motions are determined by the ϕ-mapping topological current theory.

Our previous analysis on the contributions of mirror matter admixtures in ordinary hadrons to K_L→γγ is extended to study the relevance of such contributions to the K_L→μ⁺μ^- rare decay. The mixing angle of the admixtures previously determined to describe the enhancement phenomenon in two-body non-leptonic decays of strange hadrons is used, along with recent results for the description of the strong and electromagnetic interaction parts of the transition amplitudes. We find that these admixtures give a significant contribution with a small SU(2) breaking of only 2.8%, we also find a value of ~ -17.9° for the η–η′ mixing angle consistent with some of its determinations in the literature and a preferred negative value around -16 for the local counterterm contribution χ₁+χ₂ consistent with the existence of a unique counterterm assuming lepton universality. We conclude that those mixings may be relevant in low energy physics and should not be ignored.