Modern Physics Letters A

In this paper, on a talk given at Lawrence Berkeley Laboratory, we discuss higher-order non-perturbative corrections in inclusive semileptonic decays of B mesons. First the generic calculation is reviewed and then we identify the relevant hadronic matrix-elements up to . For a quantitative analysis of these effects, the value of these new matrix-elements is estimated within an approximation scheme. We investigate the role of so-called "intrinsic-charm" operators in this decay, appearing first at order in the heavy-quark expansion. These operators induce an expansion infrared sensitive to the charm quark . Parametrically the power corrections complement the estimate of the potential impact of contributions, which we will explore. In this context, we draw semiquantitative conclusions for the expected scale of valence weak annihilation contribution in semileptonic B decays. Furthermore the effects on the integrated rate and on kinematic moments are then estimated up to .

This is a review of searches for supersymmetry (SUSY) with the ATLAS detector in proton–proton collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider (LHC) at CERN. The review covers results that have been published, or submitted for publication, up to September 2012, many of which cover the full 7 TeV data-taking period. No evidence for SUSY has been seen; some possibilities for future directions are discussed.

The present paper is devoted to the study of relativistic fermions evolving in a periodic magnetic field frozen in the magnetar's crust. The Heun's Double Confluent functions being the solutions to the Dirac-type equation, their series expansion allows us to write down the expressions of the current density components. For typical values of the magnetic induction, b₀~10¹⁵G, so that the magnetic length is much smaller than the extension of the crust, we get a nontrivial quantization law for the particle momentum along Oz.

This work addresses the analogy between the speed of sound of a viscous, barotropic, and irrotational fluid and the equation of motion for a non-massive field in a curved manifold. It will be shown that the presence of viscosity implies the introduction, into the equation of motion of the gravitational analogue, of a source term which entails the flow of energy from the non-massive field to the curvature of the spacetime manifold. The stress–energy tensor is also computed and it is found not to be constant, which is consistent with such energy interchange.

Using the ATLAS 4.7 fb^-1 data on new physics search in the jets + channel, we obtain new limits on the lighter top squark considering all its decay modes assuming that it is the next to lightest supersymmetric particle (NLSP). If the decay dominates and the production of dark matter relic density is due to NLSP–lightest supersymmetric particle (LSP) co-annihilation then the lower limit on is 240 GeV. The limit changes to 200 GeV if the decay dominates. Combining these results it follows that NLSP induced baryogenesis is now constrained more tightly.

We construct the action-angle variables for the spherical part of conformal mechanics describing the motion of a particle near extreme Kerr throat. We indicate the existence of the critical point |p_φ| = mc R_Sch (with m being the mass of the particle, c denoting the speed of light, being the Schwarzschild radius of a black hole with mass M, and γ denoting the gravitational constant), where these variables are expressed in elementary functions. Out from this point the action-angle variables are defined by the elliptic integrals. The proposed formulation allows one to easily reconstruct the whole dynamics of the particle both in initial coordinates, as well as in the so-called conformal basis, where the Hamiltonian takes the form of conventional non-relativistic conformal mechanics. The related issues, such as semiclassical quantization and supersymmetrization are also discussed.

We examine the capabilities of the modified perturbation theory (MPT) for description of W-pair production and decay in e⁺ e^- annihilation. In a model with Dyson-resummed propagators of unstable particles, we calculate even and odd contributions to the distribution in the cosine of the W^- production angle relative to the e^- beam. On comparing the results of calculations in the NNLO approximation of MPT with the exact results in the model, a coincidence of outcomes at the ILC energies is detected at the per-mille level.