W/Z + b,bbar/jets at NLO using the Monte Carlo MCFM

We summarize recent progress in next-to-leading order QCD calculations made using the Monte Carlo MCFM. In particular, we focus on the calculations of p anti-p -> W b-bbar, Z b-bbar and highlight the significant corrections to background estimates for Higgs searches in the channels WH and ZH at the Tevatron. We also report on the current progress of, and strategies for, the calculation of the process p anti-p -> W/Z + 2 jets.Comment: 4 pages, talk presented at the XXXVI Rencontres de Moriond, QCD and High Energy Hadronic Interactions, 17-24 March 2001, Les Arcs, Savoie, Franc

Ionospheric Corrections via PIM and Real-Time Data

We describe a method for removing ionospheric effects from single-frequency radio data a posteriori. This method is based on a theoretical climatological model developed by the USAF, which returns electron density as a function of position and time along the line of sight to the source. Together with a model of the earth's magnetic field, ionospheric delays and Faraday rotation values ensue. If contemoraneous ionospheric data -- GPS TEC observations or ionosonde profiles -- exist, they can be incorporated to update the modeled electron densities.Comment: 6 pages, 2 fiugres; LaTeX2e (96/12/01); uses elsart.cls (2.15, 98/07/15); to appear in New Astronomy Review

A dissipative scheme to approach the boundary of two-qubit entangled mixed states

We discuss the generation of states close to the boundary-family of maximally entangled mixed states as defined by the use of concurrence and linear entropy. The coupling of two qubits to a dissipation-affected bosonic mode is able to produce a bipartite state having, for all practical purposes, the entanglement and purity properties of one of such boundary states. We thoroughly study the effects that thermal and squeezed character of the bosonic mode have in such a process and we discuss tolerance to qubit phase-damping mechanisms. The non-demanding nature of the scheme makes it realizable in a matter-light based physical set-up, which we address in some details.Comment: 9 pages, 7 figures, RevTeX4, Accepted for publication by Physics Review

Pedalling for safety: Schoolchildren and safe active transport

This research will add to the international body of knowledge around safe active transport and its benefits for individuals and their communities. In order to achieve this, the report begins with a brief description of the risks associated with active transport, 3 and considers why active transport to school should be encouraged, despite the risks. Our dependence on cars is discussed in relation to the prevailing chauffeuring culture, before the objectives of the research are outlined. Chapter one concludes with an account of the methodology used to undertake this research, which combined a literature review and a search for educational resources with some participant observation field research. In chapter 2 we present a summary of the resources available to parents in Hamilton and provide a profile of the city, which is in many ways ideally suited to active transport, though participation rates are low. Chapter 3 discusses the benefits of active transport and the barriers to participation in it. Following a discussion that draws all the various strands together, we evaluate existing strategies with a view to endorsing those most likely to enhance safety, while also offering some further ideas on how to minimise the risks of active transport for children

Triphoton production at hadron colliders

We present next-to-leading order predictions for the production of triphoton final states at the LHC and the Tevatron. Our results include the effect of photon fragmentation for the first time and we are able to quantify the impact of different isolation prescriptions. We find that calculations accounting for fragmentation effects at leading order, and those employing a smooth cone isolation where no fragmentation contribution is required, are in reasonable agreement with one another. However, larger differences in the predicted rates arise when higher order corrections to the fragmentation functions are included. In addition we present full analytic results for the $\gamma\gamma\gamma$ and $\gamma\gamma+$jet one-loop amplitudes. These amplitudes, which are particularly compact, may be useful to future higher-order calculations. Our results are available in the Monte Carlo code MCFM.Comment: 16 pages, 4 figure

Single vortex fluctuations in a superconducting chip as generating dephasing and spin flips in cold atom traps

We study trapping of a cold atom by a single vortex line in an extreme type II superconducting chip, allowing for pinning and friction. We evaluate the atom's spin flip rate and its dephasing due to the vortex fluctuations in equilibrium and find that they decay rapidly when the distance to the vortex exceeds the magnetic penetration length. We find that there are special spin orientations, depending on the spin location relative to the vortex, at which spin dephasing is considerably reduced while perpendicular directions have a reduced spin flip rate. We also show that the vortex must be perpendicular to the surface for a general shape vortex.Comment: 6 pages, 4 figure

MCFM for the Tevatron and the LHC

A summary is given of the current status of the next-to-leading order (NLO) parton-level integrator MCFM. Some details are given about the Higgs + 2-jet process and the production and decay of $t \bar{t}$, both of which have recently been added to the code. Using MCFM, comparisons between the Tevatron running at $\sqrt{s}=2$~TeV and the LHC running at $\sqrt{s}=7$~TeV are made for standard model process including the production of Higgs bosons. The case for running the Tevatron until 16fb$^{-1}$ are accumulated by both detectors is sketched.Comment: Talk presented by R.K Ellis at Loops and Legs in Quantum Field Theory 2010, Woerlitz, Germany, April 25-30, 2010, (6 pages and 4 figures