Spanish ATLAS Tier-2: facing up to LHC Run 2 González de la Hoz, S; Peso, J Del; Fassi, F ...
Journal of physics. Conference series,
12/2015, Letnik:
664, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The goal of this work is to describe the way of addressing the main challenges of Run 2 by the Spanish ATLAS Tier-2. The considerable increase of energy and luminosity for the upcoming Run 2 with ...respect to Run 1 has led to a revision of the ATLAS computing model as well as some of the main ATLAS computing tools. In this paper, the adaptation to these changes will be described. The Spanish ATLAS Tier-2 is a R&D project which consists of a distributed infrastructure composed of three sites and its members are involved in ATLAS computing progress, namely the work in different tasks and the development of new tools (e.g. Event Index).
The production of excited charm,
D
1
(2420)
0
and
D
2
*
(2460)
0
, and charm-strange,
D
s
1
(2536)
±
, mesons in
ep
collisions was measured with the ZEUS detector at HERA using an integrated ...luminosity of 126 pb
−1
. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of
c
quarks hadronising as a given excited charm meson and to the ratios of the dominant
D
2
*
(2460)
0
and
D
s
1
(2536)
±
branching fractions. A search for the radially excited charm meson,
D
*′
(2640)
±
, was also performed. The results are compared with those measured previously and with theoretical expectations.
In this contribution we describe the performance of the Iberian (Spain and Portugal) ATLAS cloud during the first LHC running period (March 2010-January 2013) in the context of the GRID Computing and ...Data Distribution Model. The evolution of the resources for CPU, disk and tape in the Iberian Tier-1 and Tier-2s is summarized. The data distribution over all ATLAS destinations is shown, focusing on the number of files transferred and the size of the data. The status and distribution of simulation and analysis jobs within the cloud are discussed. The Distributed Analysis tools used to perform physics analysis are explained as well. Cloud performance in terms of the availability and reliability of its sites is discussed. The effect of the changes in the ATLAS Computing Model on the cloud is analyzed. Finally, the readiness of the Iberian Cloud towards the first Long Shutdown (LS1) is evaluated and an outline of the foreseen actions to take in the coming years is given. The shutdown will be a good opportunity to improve and evolve the ATLAS Distributed Computing system to prepare for the future challenges of the LHC operation.
The production of charm and beauty quarks in
ep
interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange
Q
2
>20 GeV
2
, using an integrated luminosity of ...126 pb
−1
. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta
and pseudorapidities −1.6<
η
μ
<2.3, as a function of
,
η
μ
,
Q
2
and Bjorken
x
. The charm and beauty contributions to the proton structure function
F
2
were also extracted. The results agree with previous measurements based on independent techniques and are well described by QCD predictions.
The computing model of the ATLAS experiment at the LHC (Large Hadron Collider) is based on a tiered hierarchy that ranges from Tier0 (CERN) down to end-user's own resources (Tier3). According to the ...same computing model, the role of the Tier2s is to provide computing resources for event simulation processing and distributed data analysis. Tier3 centers, on the other hand, are the responsibility of individual institutions to define, fund, deploy and support. In this contribution we report on the operations of the ATLAS Iberian Cloud centers facing data taking and we describe some of the Tier3 facilities currently deployed at the Cloud.
Exclusive electroproduction of two pions at HERA Abramowicz, H.; Aggarwal, R.; Antonov, A. ...
The European physical journal. C, Particles and fields,
01/2012, Letnik:
72, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The exclusive electroproduction of two pions in the mass range 0.4<
M
ππ
<2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb
−1
. The analysis was carried ...out in the kinematic range of 2<
Q
2
<80 GeV
2
, 32<
W
<180 GeV and |
t
|<0.6 GeV
2
, where
Q
2
is the photon virtuality,
W
is the photon-proton centre-of-mass energy and
t
is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |
F
(
M
ππ
)|, assuming that the studied mass range includes the contributions of the
ρ
,
ρ
′ and
ρ
′′ vector-meson states. The masses and widths of the resonances were obtained and the
Q
2
dependence of the cross-section ratios
σ
(
ρ
′→
ππ
)/
σ
(
ρ
) and
σ
(
ρ
′′→
ππ
)/
σ
(
ρ
) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in
e
+
e
−
→
π
+
π
−
.
Measurements of the cross sections for charged current deep inelastic scattering in
e
−
p
collisions with longitudinally polarised electron beams are presented. The measurements are based on a data ...sample with an integrated luminosity of 175 pb
−1
collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections
d
σ
/
dQ
2
,
d
σ
/
dx
and
d
σ
/
dy
are presented for
Q
2
>200 GeV
2
. The double-differential cross-section
d
2
σ
/
dxdQ
2
is presented in the kinematic range 280<
Q
2
<30 000 GeV
2
and 0.015<
x
<0.65. The measured cross sections are compared with the predictions of the Standard Model.
The local hadronic calibration scheme developed for the reconstruction and calibration of jets and missing transverse energy in ATLAS has been evaluated using data obtained during combined beam tests ...of modules of the ATLAS liquid argon endcap and forward calorimeters. These tests covered the pseudorapidity range of 2.5 < | ? | < 4.0 . The analysis has been performed using special sets of calibration weights and corrections obtained with the Geant4 simulation of a detailed beam-test setup. The evaluation itself has been performed through the careful study of specific calorimeter performance parameters such as e.g. energy response and resolution, shower shapes, as well as different physics lists of the Geant4 simulation.
The production of beauty quarks in
ep
interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared
Q
2
>10 GeV
2
, using an integrated luminosity of 363 pb
−1
. ...The beauty events were identified using electrons from semileptonic
b
decays with a transverse momentum
GeV and pseudorapidity |
η
e
|<1.5. Cross sections for beauty production were measured and compared with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function
F
2
was extracted from the double-differential cross section as a function of Bjorken-
x
and
Q
2
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this contribution an evaluation of the readiness parameters for the Spanish ATLAS Federated Tier-2 is presented, regarding the ATLAS data taking which is expected to start by the end of the year ...2009. Special attention will be paid to the Physics Analysis from different points of view: Data Management, Simulated events Production and Distributed Analysis Tests. Several use cases of Distributed Analysis in GRID infrastructures and local interactive analysis in non-Grid farms, are provided, in order to evaluate the interoperability between both environments, and to compare the different performances. The prototypes for local computing infrastructures for data analysis are described. Moreover, information about a local analysis facilities, called Tier-3, is given.
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