10735130
DIAL: Distributed Interactive Analysis of Large Datasets
DIAL will enable users to analyze very large, event-based datasets using an application that is natural to the data format. Both the dataset and the processing may be distributed over a farm, a site (collection of farms) or a grid (collection of sites). Here we describe the goals of the project, the current design and implementation, and plans for future development. DIAL is being developed within PPDG to understand the requirements that interactive analysis places on the grid and within ATLAS to enable distributed interactive analysis of event data.
40803150
Absolute differential cross section measurements for proton-deuteron elastic scattering at 641.3 and 792.7 MeV.
The absolute {ital p}-{ital d} elastic-scattering differential cross sections were measured at 641.3 and 792.7 MeV beam energies over a range of c.m. angles from {similar to}35{degree} to {similar to}115{degree} and {similar to}35{degree} to {similar to}140{degree}, respectively. The longitudinally polarized ({ital L}-type) proton beam produced by the Lamb-shift ion source at LAMPF was used. The beam intensity was measured to high accuracy ({similar to}0.1%) by a scintillator-beam particle-counting system designed and developed prior to the experiment. Typical uncertainties in the absolute cross sections were about 2--3% total, somewhat larger at back angles. The present results were compared with the existing measurements and the controversy about the previous data at 800 MeV was resolved. The present data can be fit with a relativistic multiple-scattering theory which uses off-mass-shell extrapolations of the nucleon-nucleon amplitudes suggested by the structure of derivative meson-nucleon couplings. Relativistic-impulse-approximation calculations do not fit these data at either energy.
122179155
Comparison of spin asymmetries and cross sections in π0 production by 200 GeV polarized antiprotons and protons
121758406
A large acceptance cylindrical drift chamber detector
Abstract This paper describes a large acceptance cylindrical drift chamber detector designed and built for the study of the np → pp π − reaction at neutron beam energies in the range 500–800 MeV. Details of construction, electronics, testing, and detection efficiencies and resolutions are presented.
13590622
A muon identification and combined reconstruction procedure for the ATLAS detector at the LHC at CERN
Muon identification (MUID) and high-momentum measurement accuracy is crucial to fully exploit the physics potential that will be accessible with the ATLAS experiment at the LHC. The muon energy of physics interest ranges in a large interval from few GeV, where the b-physics studies dominate the physics program, up to the highest values that could indicate the presence of new physics. The muon detection system of the ATLAS detector is characterized by two high-precision tracking systems, namely the inner detector (ID) and the muon spectrometer, (MS) plus a thick calorimeter that ensures a safe hadron absorption filtering with high-purity muons with energy above 3 GeV. In order to combine the muon tracks reconstructed in the ID and the MS, a MUID object-oriented software package has been developed. The purpose of the MUID procedure is to associate tracks found in the MS with the corresponding ID track and calorimeter information in order to identify muons at their production vertex with optimum parameter resolution. The performance of these two combined systems has been evaluated with Monte Carlo studies using single muons of fixed-transverse momentum and with full physics events.
35298179
Analyzing power measurement in inclusive Lambda 0 production with a 200 GeV/c polarized proton beam.
The considerable polarization of hyperons produced at high {ital x}{sub {ital F}} has been known for a long time and has been interpreted with various theoretical models in terms of the constituents` spin. Recently, the analyzing power in inclusive {Lambda}{sup 0} hyperon production has also been measured using the 200 GeV/{ital c} Fermilab polarized proton beam. The covered kinematic range is 0.2{le}{ital x}{sub {ital F}}{le}1.0 and 0.1{le}{ital p}{sub {ital T}}{le}1.5 GeV/{ital c}. The data indicate a negative asymmetry at large {ital x}{sub {ital F}} and moderate {ital p}{sub {ital T}}. These results can further test the current ideas on the underlying mechanisms for hyperon polarization. Copyright {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.
118986549
Chiral limit of strongly coupled lattice gauge theories
Abstract We construct a new and efficient cluster algorithm for updating strongly coupled U ( N ) lattice gauge theories with staggered fermions in the chiral limit. The algorithm uses the constrained monomer–dimer representation of the theory and should also be of interest to researchers working on other models with similar constraints. Using the new algorithm we address questions related to the chiral limit of strongly coupled U ( N ) gauge theories beyond the mean field approximation. We show that the infinite volume chiral condensate is non-zero in three and four dimensions. However, on a square lattice of size L we find ∑ x 〈 ψ ψ(x) ψ ψ(0)〉∼L 2−η for large L where η =0.420(3)/ N +0.078(4)/ N 2 . These results differ from an earlier conclusion obtained using a different algorithm. Here we argue that the earlier calculations were misleading due to uncontrolled autocorrelation times encountered by the previous algorithm.
2864130
A Remark on Schwarz's Topological Field Theory
The standard evaluation of the partition function Z of Schwarz's topological field theory results in the Ray–Singer analytic torsion. Here we present an alternative evaluation which results in Z=1. Mathematically, this amounts to a novel perspective on analytic torsion: it can be formally written as a ratio of volumes of spaces of differential forms which is formally equal to 1 by Hodge duality. An analogous result for Reidemeister combinatorial torsion is also obtained.
55869260
Relation between bare lattice coupling and MS coupling at one loop with general lattice fermions
A compact general integral formula is derived from which the fermionic contribution to the one-loop coefficient in the perturbative expansion of the MS coupling in powers of the bare lattice coupling can be extracted. It is seen to reproduce the known results for unimproved naive, staggered and Wilson fermions, and has advantageous features which facilitate the evaluation in the case of improved lattice fermion formulations. This is illustrated in the case of Wilson clover fermions, and an expression in terms of known lattice integrals is obtained in this case which gives the coefficient to much greater numerical accuracy than in the previous literature.
533804
General properties of logarithmically divergent one-loop lattice Feynman integrals
We prove that logarithmically divergent one-loop lattice Feynman integrals have the general form I(p,a) = f(p)log(aM)+g(p,M) up to terms which vanish for lattice spacing a -> 0. Here p denotes collectively the external momenta and M is an arbitrary mass scale. The f(p) is shown to be universal and to coincide with the analogous quantity in the corresponding continuum integral (regularized, e.g., by momentum cut-off). This is essential for universality of the lattice QCD beta-function and anomalous dimensions of renormalized lattice operators at one loop. The result and argument presented here are simplified versions of ones given in arXiv:0709.0781. A noteworthy feature of the argument here is that it does not involve Taylor expansion in external momenta, hence infra-red divergences associated with that expansion do not arise.
14339689
Fermionic topological charge of families of lattice gauge fields
Abstract Topological charge of families of lattice gauge fields is defined fermionically via families index theory for the overlap Dirac operator. Certain obstructions to gauge invariance of the overlap chiral fermion determinant, as well as the lattice analogues of certain obstructions to gauge fixings without the Gribov problem have natural descriptions in this context.