Modern Physics Letters A

The first year of LHC data taking provided an integrated luminosity of about 35 pb^-1 in proton–proton collisions at . The accelerator and the experiments have demonstrated an excellent performance. The experiments have obtained important physics results in many areas, ranging from tests of the Standard Model to searches for new particles. Among other results, the physics highlights have been the measurements of the W-, Z-boson and production cross-sections, improved limits on supersymmetric and other hypothetical particles and the observation of jet-quenching, elliptical flow and J/ψ suppression in lead–lead collisions at .

We analyze the stability of a class of thin-shell wormholes with spherical symmetry evolving in flat FRW spacetimes. The wormholes considered here are supported at the throat by a perfect fluid with equation of state and have a physical radius equal to aR, where a is a time-dependent function describing the dynamics of the throat and R is the background scale factor. The study of wormhole stability is done by means of the stability analysis of dynamic systems.

We construct systematically all the self-adjoint Dirac Hamiltonians with a vector 1/r and Aharonov–Bohm potential in (2+1) dimensions with taking into account the fermion spin. Then we find spectra of these self-adjoint Dirac Hamiltonians. There are one-parameter families of the self-adjoint Dirac Hamiltonians selected by physically acceptable boundary conditions. Equations determining spectra of the self-adjoint radial Dirac Hamiltonians are derived for various values of parameters. We show that the lowest fermion state in the considered potential becomes unstable when the effective charge is greater than the so-called critical charge, and that the effective charge is influenced by the magnetic flux and spin particle.

We investigate the validity of the thermodynamical properties of the universe in a new parametric model of dark energy with the equation of state w = w₀ + w₁ · z(1 + z)/(1 + z²). In the spatially homogeneous and isotropic universe, assuming that the temperature and entropy in cosmology is as in a black hole, we examine the thermodynamical properties of the universe bounded by the apparent horizon and the event horizon respectively. By analysis, we find that the first and the second laws of thermodynamics are valid inside the apparent horizon, while they break down inside the event horizon.

Requiring all massless elementary fields to have conformal scaling symmetry removes the conflict between gravitational theory and the quantum theory of elementary particles and fields. Extending this postulate to the scalar field of the Higgs model, dynamical breaking of both gauge and conformal symmetries determines parameters for the interacting fields. In uniform isotropic geometry a modified Friedmann cosmic evolution equation is derived with nonvanishing cosmological constant. Parameters determined by numerical solution are consistent with empirical data for redshifts z ≤ z_* = 1090, including luminosity distances for observed type Ia supernovae and peak structure ratios in the cosmic microwave background (CMB). The theory does not require dark matter.

In this paper, we compare the branching ratio and rate difference of electron channel to muon channel of and B →K*ℓ⁺ℓ^- decays, where is the p-wave scalar meson, in the supersymmetric models. MSSM with R parity is considered since considerable deviation from the standard model predictions can be obtained in B→X_s ℓ^-ℓ⁺. Taking C_Q1 and C_Q2 about one which is consistent with the B→K*μ⁺μ^- rate at low dileptonic invariant mass region (1 ≤ q² ≤ 6 GeV²). It is found that, firstly, the decay is measurable at LHC, secondly, in comparison with B →K*ℓ⁺ ℓ^- decay a greater deviation in the decay can be seen. Measurement of these observables for the semileptonic rare , in particular, at low q² region can give valuable information about the nature of interactions within Standard Model or beyond.

We derive the various forms of BRST symmetry using Batalin–Fradkin–Vilkovisky approach in the case of Abelian 2-form gauge theory. We show that the so-called dual BRST symmetry is not an independent symmetry but the generalization of BRST symmetry obtained from the canonical transformation in the bosonic and ghost sector. We further obtain the new forms of both BRST and dual-BRST symmetry by making a general transformation in the Lagrange multipliers of the bosonic and ghost sector of the theory.