Learn More
A search has been performed for the Standard Model Higgs boson in the data sample collected with the ALEPH detector at LEP, at centre-of-mass energies up to 209 GeV. An excess of 3 σ beyond the background expectation is found, consistent with the production of the Higgs boson with a mass near 114 GeV/c 2. Much of this excess is seen in the four-jet(More)
This paper describes the experiences of the OGSA-DAI team in designing and building a database access layer using the OGSI and the emerging DAIS GGF recommendations. This middleware is designed for enabling other UK e-Science projects that require database access and providing the basic primitives for higher-level services such as Distributed Query(More)
The cross sections and forward-backward asymmetries of hadronic and leptonic events produced in e + e − collisions at centre-of-mass energies from 130 to 183 GeV are presented. Results for e + e − , µ + µ − , τ + τ − , q¯ q, b ¯ b and c¯ c production show no significant deviation from the Standard Model predictions. This enables constraints to be set upon(More)
The rate of gluon splitting into c¯ c pairs in hadronic Z decays is measured using the data sample collected by ALEPH from 1991 to 1995. The selection is based on the identification of leptons (electrons and muons) originating from semileptonic charm decays, and on the topological properties of signal events. The result derived from the selected sample is g(More)
Operators of federated networks require timely detection and diagnosis of networking problems. For detection of such problems, access to monitoring data that exists in multiple organisations is necessary. This paper presents an ongoing work on an Alarms Service which uses a standards-based access mechanism to obtain monitoring data from multiple(More)
Hadronic Z decays into three jets are used to test QCD models of colour reconnection (CR). A sensitive quantity is the rate of gluon jets with a gap in the particle rapidity distribution and zero jet charge. Gluon jets are identified by either energy-ordering or by tagging two b-jets. The rates predicted by two string-based tunable CR models, one(More)
Search for γγ decays of a Higgs boson produced in association with a fermion pair in e + e − collisions at LEP The ALEPH Collaboration 1) Abstract A search for γγ decays of a Higgs boson is performed in the data sample collected at LEP with the ALEPH detector between 1991 and 1999. This corresponds to an integrated luminosity of 672 pb −1 at centre-of-mass(More)
Effective monitoring of multi-domain Grid networks is essential to support large operational Grid infrastructures. Timely detection of network problems is an essential part of this monitoring. In order to detect the problems, access to network monitoring data that exists in multiple organisations is necessary. This paper presents an Alarms Service that(More)
The coordination and scheduling of affiliated tasks to be run at different sites is a challenging problem, specifically in the domain of network performance monitoring. This paper presents a software implementation of the Probes Coordination Protocol (PCP) which provides a solution to this problem. The PCP allows tasks to be executed regularly on a(More)