ATLAS

Abstract:

The muon ionization cooling experiment (MICE) consists of a target, a beam line, a pion decay channel, the MICE cooling channel. Superconducting magnets are used in the pion decay channel and the MICE cooling channel. This report describes the MICE cooling channel magnets and the progress in the design and fabrication of these magnets. The MICE cooling channel consists of three types of superconducting solenoids; the spectrometer solenoids, the coupling solenoids and the focusing solenoids. The three types of magnets are being fabricated in the United States, China, and the UK respectively. The spectrometer magnets are used to analyze the muon beam before and after muon cooling. The coupling magnets couple the focusing sections and keep the muon beam contained within the iris of the RF cavities that are used to recover the muon momentum lost during ionization cooling. The focusing magnets focus the muon beam in the center of a liquid hydrogen absorber. The first of the cooling channel magnets will be operational in MICE in the spring of 2010. © 2010 IOP Publishing Ltd.

Abstract:

The associated Higgs boson production modes WH, ZH, and ttH ¯, where the Higgs boson subsequently decays to a pair of tau leptons, can be used to measure the relative branching ratios of a low-mass Higgs boson at the Large Hadron Collider and hence measure the ratio of Yukawa couplings as predicted by the Standard Model. We find that these modes can enhance coupling-ratio sensitivity with 50 fb−1 of pp collision data at a center of mass energy equal to 14 TeV, for a Higgs boson mass between 115 and 135 GeV/c2.

Abstract:

Charged particle production has been studied in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 0.44 fb?1. Distributions of scaled momenta in the Breit frame are presented for particles in the current fragmentation region. The evolution of these spectra with the photon virtuality, Q2, is described in the kinematic region 10 < Q2< 41000Ge V2. Next-to-leading-order and modified leading-log-approximation QCD calculations as well as predictions from Monte Carlo models are compared to the data. The results are also compared to e+e? annihilation data. The dependences of the pseudorapidity distribution of the particles on Q2 and on the energy in the p system, W, are presented and interpreted in the context of the hypothesis of limiting fragmentation.

Abstract:

Neutral resonances decaying to dileptons or diphotons are common in models of physics beyond the standard model. The Tevatron experiments have analyzed up to 5.4 fb−1 of dilepton and diphoton data, and found no significant evidence of such neutral resonances. The CDF and D0 experiments set the world's highest mass limits on new spin-0 sneutrinos, spin-1 gauge bosons, and spin-2 gravitons.

Abstract:

The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes. © 2010 CERN for the benefit of the ATLAS collaboration.