Fiberglass container shells form contamination-free storage units

Interchangeable molded fiberglass shells are locked together to form storage units of various depths. These units can hold components weighing 1500 pounds, are easily transportable, and protect contents from contamination

Matching the Nagy-Soper parton shower at next-to-leading order

We present an MC@NLO-like matching of next-to-leading order QCD calculations with the Nagy-Soper parton shower. An implementation of the algorithm within the HELAC-DIPOLES Monte Carlo generator is used to address the uncertainties and ambiguities of the matching scheme. First results obtained using the Nagy-Soper parton shower implementation in DEDUCTOR in conjunction with the HELAC-NLO framework are given for the pp -> top anti-top j + X process at the LHC with sqrt(s)=8 TeV. Effects of resummation are discussed for various observables.Comment: 53 pages, 18 figures, 3 tables. References and a few typos corrected, acknowledgments added, dependence on the variation of the starting shower time corrected, version to appear in JHE

Off-shell Top Quarks with One Jet at the LHC: A comprehensive analysis at NLO QCD

We present a comprehensive study of the production of top quark pairs in association with one hard jet in the di-lepton decay channel at the LHC. Our predictions, accurate at NLO in QCD, focus on the LHC Run II with a center-of-mass energy of 13 TeV. All resonant and non-resonant contributions at the perturbative order ${\cal O}(\alpha_s^4 \alpha^4)$ are taken into account, including irreducible backgrounds to $t\bar{t}j$ production, interferences and off-shell effects of the top quark and the $W$ gauge boson. We extensively investigate the dependence of our results upon variation of renormalisation and factorisation scales and parton distribution functions in the quest for an accurate estimate of the theoretical uncertainties. Additionally, we explore a few possibilities for a dynamical scale choice with the goal of stabilizing the perturbative convergence of the differential cross sections far away from the $t\bar{t}$ threshold. Results presented here are particularly relevant for searches of new physics as well as for precise measurements of the top-quark fiducial cross sections and top-quark properties at the LHC.Comment: 51 pages, 36 figures, 6 tables, version to appear in JHE

Self-consistent stationary MHD shear flows in the solar atmosphere as electric field generators

Magnetic fields and flows in coronal structures, for example, in gradual phases in flares, can be described by 2D and 3D magnetohydrostatic (MHS) and steady magnetohydrodynamic (MHD) equilibria. Within a physically simplified, but exact mathematical model, we study the electric currents and corresponding electric fields generated by shear flows. Starting from exact and analytically calculated magnetic potential fields, we solveid the nonlinear MHD equations self-consistently. By applying a magnetic shear flow and assuming a nonideal MHD environment, we calculated an electric field via Faraday's law. The formal solution for the electromagnetic field allowed us to compute an expression of an effective resistivity similar to the collisionless Speiser resistivity. We find that the electric field can be highly spatially structured, or in other words, filamented. The electric field component parallel to the magnetic field is the dominant component and is high where the resistivity has a maximum. The electric field is a potential field, therefore, the highest energy gain of the particles can be directly derived from the corresponding voltage. In our example of a coronal post-flare scenario we obtain electron energies of tens of keV, which are on the same order of magnitude as found observationally. This energy serves as a source for heating and acceleration of particles.Comment: 11 pages, 9 figures, accepted to Astronomy and Astrophysic

Mapping vesicle shapes into the phase diagram: A comparison of experiment and theory

Phase-contrast microscopy is used to monitor the shapes of micron-scale fluid-phase phospholipid-bilayer vesicles in aqueous solution. At fixed temperature, each vesicle undergoes thermal shape fluctuations. We are able experimentally to characterize the thermal shape ensemble by digitizing the vesicle outline in real time and storing the time-sequence of images. Analysis of this ensemble using the area-difference-elasticity (ADE) model of vesicle shapes allows us to associate (map) each time-sequence to a point in the zero-temperature (shape) phase diagram. Changing the laboratory temperature modifies the control parameters (area, volume, etc.) of each vesicle, so it sweeps out a trajectory across the theoretical phase diagram. It is a nontrivial test of the ADE model to check that these trajectories remain confined to regions of the phase diagram where the corresponding shapes are locally stable. In particular, we study the thermal trajectories of three prolate vesicles which, upon heating, experienced a mechanical instability leading to budding. We verify that the position of the observed instability and the geometry of the budded shape are in reasonable accord with the theoretical predictions. The inability of previous experiments to detect the ``hidden'' control parameters (relaxed area difference and spontaneous curvature) make this the first direct quantitative confrontation between vesicle-shape theory and experiment.Comment: submitted to PRE, LaTeX, 26 pages, 11 ps-fi

Noncommutative spin-1/2 representations

In this letter we apply the methods of our previous paper hep-th/0108045 to noncommutative fermions. We show that the fermions form a spin-1/2 representation of the Lorentz algebra. The covariant splitting of the conformal transformations into a field-dependent part and a \theta-part implies the Seiberg-Witten differential equations for the fermions.Comment: 7 pages, LaTe

Particle production in p-p collisions at sqrt(s) = 17 GeV within the statistical model

A thermal-model analysis of particle production of p-p collisions at sqrt(s) = 17 GeV using the latest available data is presented. The sensitivity of model parameters on data selections and model assumptions is studied. The system-size dependence of thermal parameters and recent differences in the statistical model analysis of p-p collisions at the super proton synchrotron (SPS) are discussed. It is shown that the temperature and strangeness undersaturation factor depend strongly on kaon yields which at present are still not well known experimentally. It is conclude, that within the presently available data at the SPS it is rather unlikely that the temperature in p-p collisions exceeds significantly that expected in central collisions of heavy ions at the same energy.Comment: 6 pages, 3 figures, submitted to Phys. Rev.