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[show abstract]
[hide abstract]
ABSTRACT: Commercially available high performance gigabit Ethernet (GbE) switches are optimized mostly for Internet and standard LAN application traffic. DAQ systems on the other hand usually make use of very specific traffic patterns, with e.g. deterministic arrival times. Industry's accepted loss-less limit of 99.999% may be still unacceptably high for DAQ purposes, as e.g. in the case of the LHCb readout system. In addition, even switches passing this criteria under random traffic can show significantly higher loss rates if subject to our traffic pattern, mainly due to buffer memory limitations. We have evaluated the performance of several switches, ranging from "pizza-box" devices with 24 or 48 ports up to chassis based core switches in a testbed capable to emulate realistic traffic patterns as expected in the readout system of our experiment. The results obtained in our tests have been used to refine and parametrize our packet level simulation of the complete LHCb readout network. In this paper we report on the results of our tests, and present the outcome of the simulation using realistic switch models.
Real Time Conference, 2005. 14th IEEE-NPSS; 07/2005
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J Zhao,
S J Zhou,
G Y Zhu,
R Y Zhu,
Q. Q. Zhu,
H L Zhuang,
A. Zichichi,
B. Zimmermann,
M. Zoller,
A. N. M. Zwart
[show abstract]
[hide abstract]
ABSTRACT: The shadowing of high-energy cosmic rays by the Moon has been observed with a significance of 9.4 standard deviations with the L3 + C muon spectrometer at CERN. A significant effect of the Earth magnetic field is observed. Since no event deficit on the east side of the Moon has been observed, an upper limit at 90% confidence level on the antiproton to proton ratio of 0.11 is obtained for primary energies around 1 TeV. © 2005 Elsevier B.V. All rights reserved.
Astroparticle Physics 03/2005; 23:411-434. · 3.22 Impact Factor
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia,
V.A. Naumov
[show abstract]
[hide abstract]
ABSTRACT: The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0degrees to 58degrees. Due to the large exposure of about 150 m**2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +/- 0.003(stat.) +/-0.019(syst.).
Thw L3+C group dedicates this publication to the late Bianca Monteleoni.
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J Zhao,
S J Zhou,
G Y Zhu,
R Y Zhu,
H L Zhuang,
Q. Q. Zhu,
A. Zichichi,
B. Zimmermann,
M. Zoller,
A. N. M. Zwart
[show abstract]
[hide abstract]
ABSTRACT: The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0degrees to 58degrees. Due to the large exposure of about 150 m**2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +/- 0.003(stat.) +/-0.019(syst.).
(C) 2004 Elsevier B.V. All rights reserved.
Physics Letters B 08/2004; 598:15-32. · 3.95 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The LHCb software trigger has two levels: a high-speed trigger running at 1 MHz with strictly limited latency and a second level running below 40 kHz without latency limitations. The trigger strategy requires full flexibility in the distribution of the installed CPU power to the two software trigger levels because of the unknown background levels and event topology distribution at the time the LHC accelerator will start its operation. This requirement suggests using a common CPU farm for both trigger levels fed by a common data acquisition (DAQ) infrastructure. The limited latency budget of the first level of software trigger has an impact on the organization of the CPU farm performing the trigger function for optimal usage of the installed CPU power. We will present the architecture and the design of the hardware infrastructure for the entire LHCb software triggering system based on Ethernet as link technology that fulfills these requirements. The performance of the event-building of the combined traffic of both software trigger levels, as well as the expected scale of the system will be presented.
IEEE Transactions on Nuclear Science 07/2004; · 1.45 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Network processors (NP), originally developed for applications in high-end network routers, have a great potential as building blocks for a high-speed networked data acquisition (DAQ)-Trigger system. After an introduction to NP, we will present several applications which illustrate their power in coping with high event rates and aggregate traffic of above 10 GB/s. All these applications can be implemented in a single, versatile, generic NP-based module, where the specific functionality is provided by the software. We will discuss the impact of protocol overheads on link utilization, and demonstrate a NP-based way of enhancing the portion of the bandwidth occupied by user data. One other application deals with sorting of trigger decision frames, and finally, we will look into the advantages of implementing a large switching network with the NP-based module.
IEEE Transactions on Nuclear Science 07/2004; · 1.45 Impact Factor
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J H Field,
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia
-
V.A. Naumov,
P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi, [......],
J H Field,
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia
[show abstract]
[hide abstract]
ABSTRACT: A comparison between the L3+C measurements of the atmospheric muon spectrum and charge ratio and calculations performed with CORT is shortly discussed.
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J H Field,
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia
[show abstract]
[hide abstract]
ABSTRACT: The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0degrees to 58degrees. Due to the large exposure of about 150 m**2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +/- 0.003(stat.) +/-0.019(syst.).
Thw L3+C group dedicates this publication to the late Bianca Monteleoni.
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P. Bagnaia,
A. Bajo,
G. Baksay,
L. Baksay,
S. V. Baldew,
S. Banerjee, A. Barczyk,
R. Barillere,
P. Bartalini,
M. Basile, [......],
A. Zalite,
Y. Zalite,
Z. P. Zhang,
J. Zhao,
G. Y. Zhu,
R. Y. Zhu,
H. L. Zhuang,
A. Zichichi,
B. Zimmermann,
M. Zoller
Physics Letters B 03/2004; 585:53-62. · 3.95 Impact Factor
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
M. van den Akker,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub, [......],
J H Field,
F. Filthaut,
W Fisher,
I Fisk,
G Forconi,
K. Freudenreich,
C Furetta,
Y. Galaktionov,
S N Ganguli,
P. Garcia-Abia
[show abstract]
[hide abstract]
ABSTRACT: The L3+C muon spectrum is recalculated using the method of least squares. Due to the large statistics and the good momentum resolution of L3+C, this method can be applied without additional constraints to the data. Good agreement with the current preliminary L3+C results is found. In order to keep the correlations between different data points low, a new surface momentum binning is proposed.
Given the optimal statistical properties of the least square method, it should be used for the final L3+C muon spectrum.
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P. Bagnaia,
A. Bajo,
G. Baksay,
L. Baksay,
S. V. Baldew,
S. Banerjee, A. Barczyk,
R. Barillere,
P. Bartalini,
M. Basile, [......],
A. Zalite,
Y. Zalite,
Z. P. Zhang,
J. Zhao,
G. Y. Zhu,
R. Y. Zhu,
H. L. Zhuang,
A. Zichichi,
B. Zimmermann,
M. Zoller
[show abstract]
[hide abstract]
ABSTRACT: Bose-Einstein correlations in W-pair production at LEP are investigated
in a data sample of 629 pb^-1 collected by the L3 detector at
centre-of-mass energies of 189-209 GeV. Bose-Einstein correlations
between pions within a W decay are observed and found to be in good
agreement with those in light-quark Z decay. No evidence is found for
Bose-Einstein correlations between hadrons coming from different W's in
the same event.
Physics Letters B 10/2002; 547:139-150. · 3.95 Impact Factor
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P. Bagnaia,
A. Bajo,
G. Baksay,
L. Baksay,
S. V. Baldew,
S. Banerjee, A. Barczyk,
R. Barillere,
P. Bartalini,
M. Basile, [......],
A. Zalite,
Y. Zalite,
Z. P. Zhang,
J. Zhao,
G. Y. Zhu,
R. Y. Zhu,
H. L. Zhuang,
A. Zichichi,
B. Zimmermann,
M. Zoller
[show abstract]
[hide abstract]
ABSTRACT: Single W boson production in electron-positron collisions is studied
with the L3 detector at centre-of-mass energies between 192 GeV and 209
GeV. Events with two acoplanar hadronic jets or a single energetic
lepton are selected, and the single W cross section is measured.
Combining the results with measurements at lower centre-of-mass
energies, the ratio of the measured cross section to the Standard Model
expectation is found to be 1.12^{+0.11}_{-0.10}+/-0.03. From all single
W data, the WWgamma gauge coupling parameter kappa_gamma is measured to
be 1.116^{+0.082}_{-0.086}+/-0.068.
Physics Letters B 10/2002; 547:151-163. · 3.95 Impact Factor
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Collaboration,
M. Acciarri,
P. Achard,
O. Adriani,
M. Aguilar-Benitez,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
M. G. Alviggi, [......],
S. C. Yeh,
A. Zalite,
Y. Zalite,
Z. P. Zhang,
G. Y. Zhu,
R. Y. Zhu,
A. Zichichi,
G. Zilizi,
B. Zimmermann,
M. Zöller
[show abstract]
[hide abstract]
ABSTRACT: The production of c and b quarks /γγ collisions is studied
with the L3 detector at LEP with 410 pb-1 of data, collected
at centre-of-mass energies from 189 GeV to 202 GeV. Hadronic final
states containing c and b quarks are identified by detecting electrons
or muons from their semileptonic decays. The cross sections
σ(e+e--->e+e-
cc¯X) and
σ(e+e--->e+e-
bb¯X) are measured and compared to next-to-leading order
perturbative QCD calculations. The cross section of b production is
measured in /γγ collisions for the first time. It is in
excess of the QCD prediction by a factor of three.
Physics Letters B 02/2001; 503:10-20. · 3.95 Impact Factor
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Collaboration,
M. Acciarri,
P. Achard,
O. Adriani,
M. Aguilar-Benitez,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
M. G. Alviggi, [......],
S. C. Yeh,
An. Zalite,
Yu. Zalite,
Z. P. Zhang,
G. Y. Zhu,
R. Y. Zhu,
A. Zichichi,
G. Zilizi,
B. Zimmermann,
M. Zöller
[show abstract]
[hide abstract]
ABSTRACT: The data collected by the L3 experiment at LEP at a centre-of-mass
energy of 188.6 GeV are used to measure the W-pair production cross
section and the W-boson decay branching fractions. These data correspond
to an integrated luminosity of 176.8 pb-1. The total cross
section for W-pair production, combining all final states, is measured
to be σWW=16.24+/-0.37 (stat.)+/-0.22 (syst.) pb.
Including our data collected at lower centre-of-mass energies, the
hadronic branching fraction of the W-boson is determined to be
/B(W-->qq)=[68.20+/-0.68 (stat.)+/-0.33 (syst.)]%. The results agree
with the Standard Model predictions.
Physics Letters B 11/2000; 496:19-33. · 3.95 Impact Factor
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M Acciarri,
P. Achard,
O Adriani,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
G Ambrosi,
H Anderhub, [......],
P Bagnaia,
L Baksay,
A Balandras,
S Banerjee, A. Barczyk,
R. Barillere,
L Barone,
P Bartalini,
M Basile,
F Behner
[show abstract]
[hide abstract]
ABSTRACT: We measure the masses, decay widths and relative production rate of orbitally excited B mesons using 1.25 million hadronic Z decays recorded by the L3 detector. B-meson candidates are inclusively reconstructed and combined with charged pions produced at the primary event vertex. An excess of events above the expected background in the Bp mass spectrum in the region 5.6--5.8 GeV is interpreted as resulting from the decay B )) ^TMB Z ) .
02/2000;
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Collaboration,
M. Acciarri,
O. Adriani,
M. Aguilar-Benitez,
S. Ahlen,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
G. Alverson, [......],
P. Zemp,
Y. Zeng,
Z. Zhang,
Z. P. Zhang,
B. Zhou,
Y. Zhou,
G. Y. Zhu,
R. Y. Zhu,
A. Zichichi,
F. Ziegler
Physics Letters B 04/1998; 427:409-412. · 3.95 Impact Factor
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Collaboration,
M. Acciarri,
O. Adriani,
M. Aguilar-Benitez,
S. Ahlen,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
G. Alverson, [......],
Yu. Zalite,
P. Zemp,
Y. Zeng,
Z. Zhang,
Z. P. Zhang,
B. Zhou,
G. Y. Zhu,
R. Y. Zhu,
A. Zichichi,
F. Ziegler
[show abstract]
[hide abstract]
ABSTRACT: We report on measurements of mass and total decay width of the W boson
and of triple-gauge-boson couplings, γWW and ZWW, with the L3
detector at LEP. W-pair events produced in e+e-
interactions between 161GeV and 172GeV centre-of-mass energy are
selected in a data sample corresponding to a total luminosity of 21.2
pb-1. The mass and total decay width of the W boson are
determined to be MW=80.75+0.26-0.27
(exp.)+/-0.03 (LEP) GeV and
ΓW=1.74+0.88-0.78 (stat.)+/-0.25
(syst.) GeV, respectively. Limits on anomalous triple-gauge-boson
couplings, γWW and ZWW, are determined, in particular
-1.5<δZ<1.9 (95% CL), excluding vanishing ZWW
coupling at more than 95% confidence level.
Physics Letters B 10/1997; 413:176-190. · 3.95 Impact Factor
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Collaboration,
M. Acciarri,
O. Adriani,
M. Aguilar-Benitez,
S. Ahlen,
J. Alcaraz,
G. Alemanni,
J. Allaby,
A. Aloisio,
G. Alverson, [......],
Yu. Zalite,
P. Zemp,
Y. Zeng,
Z. Zhang,
Z. P. Zhang,
B. Zhou,
G. Y. Zhu,
R. Y. Zhu,
A. Zichichi,
F. Ziegler
[show abstract]
[hide abstract]
ABSTRACT: A search for the Standard Model Higgs boson has been performed with the
L3 detector at LEP. The data sample was collected at three
centre-of-mass energies, 161.3, 170.3 and 172.3GeV with integrated
luminosities of 10.8, 1.0 and 9.2 pb, respectively. No Higgs signal is
observed. In combination with previous data taken at the Z resonance, a
lower Higgs mass limit, MH>69.5GeV, is obtained at 95%
confidence level.
Physics Letters B 09/1997; 411:373-386. · 3.95 Impact Factor
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P. Achard,
O Adriani,
M. Aguilar-Benitez,
J Alcaraz,
G. Alemanni,
J. Allaby,
A Aloisio,
M G Alviggi,
H Anderhub,
V P Andreev, [......],
A Zalite,
Y. Zalite,
Z P Zhang,
J Zhao,
G Y Zhu,
R Y Zhu,
H L Zhuang,
A. Zichichi,
B. Zimmermann,
M. Zoller
[show abstract]
[hide abstract]
ABSTRACT: Inclusive jet production, e+e(-) --> e(+)e(-) jet X, is studied using 560 pb(-1) of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 209 GeV. The inclusive differential cross section is measured using a k(1), jet algorithm as a function of the jet transverse momentum, p(t), in the range 3 < p(t) < 50 GeV for a pseudorapidity, eta, in the range -1 < eta < 1. This cross section is well represented by a power law. For high p(t), the measured cross section is significantly higher than the NLO QCD predictions, as already observed for inclusive pi(+/-) and pi(0) production. (C) 2004 Published by Elsevier B.V.
Physics Research Publications.
