T. Isobe

Data transfer over the wide area network with a large round trip time

A Tier-2 regional center is running at the University of Tokyo in Japan. This center receives a large amount of data of the ATLAS experiment from the Tier-1 center in France. Although the link between the two centers has 10Gbps bandwidth, it is not a dedicated link but is shared with other traffic, and the round trip time is 290ms. It is not easy to exploit the available bandwidth for such a link, so-called long fat network. We performed data transfer tests by using GridFTP in various combinations of the parameters, such as the number of parallel streams and the TCP window size. In addition, we have gained experience of the actual data transfer in our production system where the Disk Pool Manager (DPM) is used as the Storage Element and the data transfer is controlled by the File Transfer Service (FTS). We report results of the tests and the daily activity, and discuss the improvement of the data transfer throughput.

A hadron blind detector for the PHENIX experiment at RHIC

A hadron blind detector (HBD) is being developed for an upgrade of the PHENIX experiment at RHIC. The HBD is a windowless Cherenkov detector, operated with pure CF/sub 4/ in a special proximity focus configuration. The detector consists of a 50 cm long radiator, directly coupled to a triple GEM detector which has a CsI photocathode evaporated on the top surface of the uppermost GEM foil, and a pad readout at the bottom of the GEM stack. Detailed studies of the detector performance, including hadron rejection, figure of merit, N/sub 0/, number of photoelectrons and efficiency are presented. These studies include measurements performed with a UV lamp, an /sup 55/Fe X-ray source and an /sup 241/Am alpha source. Results will also be given on aging studies of the GEM foils and the CsI photocathode in pure CF/sub 4/.

Search for resonances decaying into top quark pairs with ATLAS

Some models, including the so‐called Randall‐Sundrum model, predict the existence of heavy Kaluza‐Klein resonances decaying mainly into top quarks. The prospects to discover those resonances in the ATLAS experiment at the LHC are discussed. Special emphasis is given to the techniques used to identify and reconstruct top quarks at high‐pT.

Performance of a disk storage system at a Tier-2 site

It is expected that a WLCG Tier-2 site plays a major role in the user analysis in addition to generating Monte Carlo simulation data. For the user analysis, the data storage system should be designed properly for sustaining massive data access from a large number of analysis jobs by the end users within the LAN, and also for the data transfer from the Tier-1 site over theWAN. The Tokyo Tier-2 centre provides 400 TB of disk and 1000 kSI2K of CPU to the ATLAS VO. As the data storage manager, the gLite DPM is deployed, which is common at the Tier-2 sites. In this talk, we present the architecture of our DPM storage system and its performance as well as operational experiences.

Grid Operation at Tokyo Tier-2 Centre for ATLAS

International Centre for Elementary Particle Physics, the University of Tokyo, has been involved in the Worldwide LHC Computing Grid since 2003. After extensive R&D experience of the PC computing farm, disk and tape storage systems, network technology and the integration of these components, it is now operating a regional centre for the ATLAS data analysis. The regional centre includes an ATLAS Tier-2 site which is running the gLite middleware developed by the Enabling Grids for E-sciencE (EGEE) project. One of the biggest challenges at the regional centre is efficient data transfer between the Tier-2 site in Tokyo and other sites, in particular the associated Tier-1 site in France, because the large round trip time due to the long distance makes it difficult to transfer data at a high rate. We have been studying to achieve a good performance of the data transfer, and some results of network tests and ATLAS data transfer are described. Hardware and software components and the operational experience are also reported in this article.

Measurement of Neutral pions in √NN=200 GeV and 62.4 GeV Au+Au collisions at RHIC-PHENIX

Neutral pions (

Measurement of neutral pions in s(NN)**(1/2) =200-GeV and 62.4-GeV Au + Au collisions at RHIC-PHENIX

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The role of core excitations in the structure and decay of the 16+ spin-gap isomer in 96Cd

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Measurement of Neutral Pions in v s NN = 200 GeV and 62.4 GeV Au+Au Collisions at RH

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