4,227 research outputs found
Use of glide-ins in CMS for production and analysis
With the evolution of various grid federations, the Condor glide-ins represent a key feature in providing a homogeneous pool of resources using late-binding technology. The CMS collaboration uses the glide-in based Workload Management System, glideinWMS, for production (ProdAgent) and distributed analysis (CRAB) of the data. The Condor glide-in daemons traverse to the worker nodes, submitted via Condor-G. Once activated, they preserve the Master-Worker relationships, with the worker first validating the execution environment on the worker node before pulling the jobs sequentially until the expiry of their lifetimes. The combination of late-binding and validation significantly reduces the overall failure rate visible to CMS physicists. We discuss the extensive use of the glideinWMS since the computing challenge, CCRC-08, in order to prepare for the forthcoming LHC data-taking period. The key features essential to the success of large-scale production and analysis on CMS resources across major grid federations, including EGEE, OSG and NorduGrid are outlined. Use of glide-ins via the CRAB server mechanism and ProdAgent, as well as first hand experience of using the next generation CREAM computing element within the CMS framework is discussed
Large Scale Job Management and Experience in Recent Data Challenges within the LHC CMS experiment
From its conception the job management system has been distributed to increase scalability and robustness. The system consists of several applications (called ProdAgents) which manage Monte Carlo, reconstruction and skimming jobs on collections of sites within different Grid environments (OSG, NorduGrid, LCG) and submission systems such as GlideIn, local batch, etc...
Production of simulated data in CMS mainly takes place on so called Tier2s (small to medium size computing centers) resources. Approximately ~50% of the CMS Tier2 resources are allocated to running simulation jobs. While the so-called Tier1s (medium to large size computing centers with high capacity tape storage systems) will be mainly used for skimming and reconstructing detector data. During the last one and a half years the job management system has been adapted such that it can be configured to convert Data Acquisition (DAQ) / High Level Trigger (HLT) output from the CMS detector to the CMS data format and manage the real time data stream from the experiment. Simultaneously the system has been upgraded to facilitate the increasing scale of the CMS production and adapting to the procedures used by its operators.
In this paper we discuss the current (high level) architecture of ProdAgent, the experience in using this system in computing challenges, feedback from these challenges, and future work including migration to a set of core libraries to facilitate convergence between the different data management projects within CMS that deal with analysis, simulation, and initial reconstruction of real data. This migration is important, as it will decrease the code footprint used by these projects and increase maintainability of the code base
ASCR/HEP Exascale Requirements Review Report
This draft report summarizes and details the findings, results, and
recommendations derived from the ASCR/HEP Exascale Requirements Review meeting
held in June, 2015. The main conclusions are as follows. 1) Larger, more
capable computing and data facilities are needed to support HEP science goals
in all three frontiers: Energy, Intensity, and Cosmic. The expected scale of
the demand at the 2025 timescale is at least two orders of magnitude -- and in
some cases greater -- than that available currently. 2) The growth rate of data
produced by simulations is overwhelming the current ability, of both facilities
and researchers, to store and analyze it. Additional resources and new
techniques for data analysis are urgently needed. 3) Data rates and volumes
from HEP experimental facilities are also straining the ability to store and
analyze large and complex data volumes. Appropriately configured
leadership-class facilities can play a transformational role in enabling
scientific discovery from these datasets. 4) A close integration of HPC
simulation and data analysis will aid greatly in interpreting results from HEP
experiments. Such an integration will minimize data movement and facilitate
interdependent workflows. 5) Long-range planning between HEP and ASCR will be
required to meet HEP's research needs. To best use ASCR HPC resources the
experimental HEP program needs a) an established long-term plan for access to
ASCR computational and data resources, b) an ability to map workflows onto HPC
resources, c) the ability for ASCR facilities to accommodate workflows run by
collaborations that can have thousands of individual members, d) to transition
codes to the next-generation HPC platforms that will be available at ASCR
facilities, e) to build up and train a workforce capable of developing and
using simulations and analysis to support HEP scientific research on
next-generation systems.Comment: 77 pages, 13 Figures; draft report, subject to further revisio
Magnetic moment of the pentaquark with light-cone QCD sum rules
In this article, we study the magnetic moment of the pentaquark state as diquark-diquark-antiquark () state in the
framework of the light-cone QCD sum rules approach. The numerical results
indicate the magnetic moment of the pentaquark state is about
.Comment: 10 pages, 1 figure. The main contents of this article is included in
hep-ph/0503007, this article will not be submitted to a journal for
publicatio
f0(980) meson as a K bar K molecule in a phenomenological Lagrangian approach
We discuss a possible interpretation of the f0(980) meson as a hadronic
molecule - a bound state of K and bar K mesons. Using a phenomenological
Lagrangian approach we calculate the strong f0(980) to pi pi and
electromagnetic f0(980) to gamma gamma decays. The compositeness condition
provides a self-consistent method to determine the coupling constant between f0
and its constituents, K and bar K. Form factors governing the decays of the
f0(980) are calculated by evaluating the kaon loop integrals. The predicted
f0(980) to pi pi and f0(980) to gamma gamma decay widths are in good agreement
with available data and results of other theoretical approaches.Comment: 21 pages, 11 figures, revised version accepted for publication in
Eur. Phys. J.
Measurements of the reaction of antiproton annihilation at rest at three hydrogen target densities
The proton-antiproton annihilation at rest into the final state
was measured for three different target densities: liquid hydrogen, gaseous
hydrogen at NTP and at a low pressure of 5 mbar. The yield of this reaction in
the liquid hydrogen target is smaller than in the low-pressure gas target. The
branching ratios of the channel were calculated on the basis of
simultaneous analysis of the three data samples. The branching ratio for
annihilation into from the protonium state turns out to be
about ten times smaller as compared to the one from the state.Comment: 10 pages, 3 Postscript figures. Accepted by Physics Letters
One-pot Selective Formylation and Claisen Rearrangement on Calix[4]arenes
A versatile synthon with formyl and allyl groups at the upper rim of calix[4]arene has been synthesized in two steps. Selective formylation of 25,27-diallyloxy-26,28-dihydroxycalix[4]arene, along with the Claisen rearrangement of the allyl groups, was achieved by reaction with hexamethylenetetraamine (hexamine) in glacial acetic acid. A control reaction of the dipropyl analogue shows that the selective formylation takes place independently of the Claisen rearrangement. The crystal structure of the dimethylacetal derivative of 5,17-diformyl-11,23-diallylcalix[4]arene is reported
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