Confronting QCD Instantons with HERA Data

The sensitivity of existing HERA data on the hadronic final state in deep-inelastic scattering (DIS) to processes induced by QCD instantons is systematically investigated. The maximally allowed fraction of such processes in DIS is found to be on the percent level in the kinematic domain 0.0001 < x-Bjorken < 0.01 and 5 < Q squared < 100 GeV squared. The best limits are obtained from the multiplicity distribution.Comment: 5 pages, latex, entire paper w. tex, style and figure

Dual-layer network representation exploiting information characterization

In this paper, a logical dual-layer representation approach is proposed to facilitate the analysis of directed and weighted complex networks. Unlike the single logical layer structure, which was widely used for the directed and weighted flow graph, the proposed approach replaces the single layer with a dual-layer structure, which introduces a provider layer and a requester layer. The new structure provides the characterization of the nodes by the information, which they provide to and they request from the network. Its features are explained and its implementation and visualization are also detailed. We also design two clustering methods with different strategies respectively, which provide the analysis from different points of view. The effectiveness of the proposed approach is demonstrated using a simplified example. By comparing the graph layout with the conventional directed graph, the new dual-layer representation reveals deeper insight into the complex networks and provides more opportunities for versatile clustering analysis.The National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG-0310-1004)

Teachers Perceptions of Interventions for Children with Autism in a School Setting

Navigating the topic of autism can be difficult because there is so much recent research covering a vast range of information. The present study focuses on interventions for children with autism in a school setting. The interventions being reviewed are social stories, visual cues, and family support. The definition and evaluation of social stories and visual cues in academic settings will be discussed. The population of parents of children with autism will also be examined. Research suggests appropriate use of social stories and visual cues in academic settings are effective and positive; however the transfer into nonacademic settings is limited, suggesting a need for more resources in nonacademic settings. The implication is resources be made available to parents of children with autism

Transverse Electron Cooling from the Time Evolution of the Profiles to Drift Velocities of the Oscillation Amplitudes

When a beam in a synchrotron is subjected to transverse cooling, the betatron oscillation amplitudes of the individual particles are reduced. A method to establish the velocity of the amplitude reduction as a function of the amplitude itself has been developed. The beam profile can be measured along the cooling process with for example beam ionisation monitors. From successive profiles one computes the time evolution of the amplitude distribution, which in turn allows the determination of the amplitude reduction velocity. This method could be applied to investigate the influence of the transverse electron temperature on electron cooling performance

New Methods to Create Hollow Bunches

New methods to create hollow distributions in longitudinal phase space based on manipulations with a double harmonic RF system at high energy are presented with application to the PS Booster synchrotron (PSB). Whereas the first tenatative to create hollow bunches at the PSB aimed to improve the performance of the PSB itself, these new methods are expected to reduce the limitations due to direct space charge forces in the receiving PS (where no double harmonic RF system is available) after transfer. One method aims to introduce empty phase space in the centre of the phase space by recombination of the beam in one bucket with another empty bucket. The second method is based on redistribution of phase space surfaces during the transfer of the beam from one second harmonic sub-bucket to another. During that process, phase space surfaces are exchanged and low density from the periphery ends up in the centre, whereas the high density surfaces from the centre are transferred to the periphery. Both methods have been simulated by particle tracking. The second method has been applied in practice at the PSB. The set-up turned out to be simple and fast, and to yield hollow distributions with good reproducibility

The LHC as a Proton-Nucleus Collider

Following its initial operation as a proton-proton (p-p) and heavy-ion (208Pb82+-208Pb82+) collider, the LHC is expected to operate as a p-Pb collider. Later it may collide protons with other lighter nuclei such as 40Ar18+ or 16O8+. We show how the existing proton and lead-ion injector chains may be efficiently operated in tandem to provide these hybrid collisions. The two-in-one magnet design of the LHC main rings imposes different revolution frequencies for the two beams in part of the magnetic cycle. We discuss and evaluate the consequences for beam dynamics and estimate the potential performance of the LHC as a proton-nucleus collider

RF Scenarios for Pb54+ Ions in the PS2

This note analyses some of the rf scenarios that are presently being considered for lead ions in the PS2. An earlier note principally concerning protons [1] highlighted the problem of the large revolution frequency swing of ions in the PS2 and the issue of bunching factor with direct injection from the LEIR machine. We present solutions based on additional rf systems in LEIR and consider the 40 MHz principal rf system proposed for the PS2 in the earlier work to have switchable tuning ranges to cover the large frequency swing required

Systematic error studies for the charged particle EDM measurement proposal

Proposals aimed at measuring the Electric Dipole Moment (EDM) for charged particles require a good understanding of the systematic errors that can contribute to a vertical spin buildup mimicking the EDM signal to be detected. In what follows, a method of averaging emanating from the Bogoliubov-Krylov Mitropolski method is employed to solve the T-BMT equation and calculate the Berry phases arising for the storage ring frozen spin concept. The formalism employed proved to be particularly useful to determine the evolution of the spin at the observation point, i.e. at the location of the polarimeter. Several selected cases of lattice imperfections were simulated and benchmarked with the analytical estimates. This allowed the proof of the convergence of the numerical simulations and helped gain better understanding of the systematic errors