2,744 research outputs found
The ZEUS Forward Plug Calorimeter with Lead-Scintillator Plates and WLS Fiber Readout
A Forward Plug Calorimeter (FPC) for the ZEUS detector at HERA has been built
as a shashlik lead-scintillator calorimeter with wave length shifter fiber
readout. Before installation it was tested and calibrated using the X5 test
beam facility of the SPS accelerator at CERN. Electron, muon and pion beams in
the momentum range of 10 to 100 GeV/c were used. Results of these measurements
are presented as well as a calibration monitoring system based on a Co
source.Comment: 38 pages (Latex); 26 figures (ps
Observation of Scaling Violations in Scaled Momentum Distributions at HERA
Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of and using the ZEUS detector. The
evolution of the scaled momentum, , with in the range 10 to 1280
, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of .Comment: 21 pages including 4 figures, to be published in Physics Letters B.
Two references adde
DIRAC framework evaluation for the -LAT and CTA experiments
DIRAC (Distributed Infrastructure with Remote Agent Control) is a general
framework for the management of tasks over distributed heterogeneous computing
environments. It has been originally developed to support the production
activities of the LHCb (Large Hadron Collider Beauty) experiment and today is
extensively used by several particle physics and biology communities. Current
( Large Area Telescope -- LAT) and planned (Cherenkov Telescope Array --
CTA) new generation astrophysical/cosmological experiments, with very large
processing and storage needs, are currently investigating the usability of
DIRAC in this context. Each of these use cases has some peculiarities:
-LAT will interface DIRAC to its own workflow system to allow the access
to the grid resources, while CTA is using DIRAC as workflow management system
for Monte Carlo production and analysis on the grid. We describe the prototype
effort that we lead toward deploying a DIRAC solution for some aspects of
-LAT and CTA needs.Comment: proceedings to CHEP 2013 conference : http://www.chep2013.org
HTC Scientific Computing in a Distributed Cloud Environment
This paper describes the use of a distributed cloud computing system for
high-throughput computing (HTC) scientific applications. The distributed cloud
computing system is composed of a number of separate
Infrastructure-as-a-Service (IaaS) clouds that are utilized in a unified
infrastructure. The distributed cloud has been in production-quality operation
for two years with approximately 500,000 completed jobs where a typical
workload has 500 simultaneous embarrassingly-parallel jobs that run for
approximately 12 hours. We review the design and implementation of the system
which is based on pre-existing components and a number of custom components. We
discuss the operation of the system, and describe our plans for the expansion
to more sites and increased computing capacity
Technical support for Life Sciences communities on a production grid infrastructure
Production operation of large distributed computing infrastructures (DCI)
still requires a lot of human intervention to reach acceptable quality of
service. This may be achievable for scientific communities with solid IT
support, but it remains a show-stopper for others. Some application execution
environments are used to hide runtime technical issues from end users. But they
mostly aim at fault-tolerance rather than incident resolution, and their
operation still requires substantial manpower. A longer-term support activity
is thus needed to ensure sustained quality of service for Virtual Organisations
(VO). This paper describes how the biomed VO has addressed this challenge by
setting up a technical support team. Its organisation, tooling, daily tasks,
and procedures are described. Results are shown in terms of resource usage by
end users, amount of reported incidents, and developed software tools. Based on
our experience, we suggest ways to measure the impact of the technical support,
perspectives to decrease its human cost and make it more community-specific.Comment: HealthGrid'12, Amsterdam : Netherlands (2012
Vers une fédération de Cloud Académique dans France Grilles
Vers une fédération de Cloud Académique dans France Grille
Measurement of relative branching fractions of B decays to Ï(2S) and J/Ï mesons
The relative rates of B-meson decays into J/Ï
and Ï(2S) mesons are measured for the three decay modes
in pp collisions recorded with the LHCb detector. The ratios
of branching fractions (B) are measured to be
B(B
+âÏ(2S)K
+
)
B(B+âJ/ÏK+)
= 0.594±0.006(stat)±0.016(syst)±0.015(RÏ),
B(B0âÏ(2S)K
â0)
B(B0âJ/ÏKâ0)
= 0.476±0.014(stat)±0.010(syst)±0.012(RÏ),
B(B0
s
âÏ(2S)Ï)
B(B0
s
âJ/ÏÏ)
= 0.489±0.026(stat)±0.021(syst)±0.012(RÏ),
where the third uncertainty is from the ratio of the Ï(2S)
and J/Ï branching fractions to ÎŒ
+
Ό
â.
1 Introductio
- âŠ