We present an updated search for the Standard Model Higgs boson in the H arrow right bb and H arrow right tau super(+)tau super(-) decay modes performed by the ATLAS experiment using 4.7 fb ...super(-1)of LHC data at radicals = 7 TeV and 13.0 fb super(-1)at radicals = 8 TeV delivered in 2011 and 2012 respectively. No significant excess is observed. For mH = 125 GeV the observed (expected) upper limit at 95% confidence level on the cross section times the branching ratio is found to be 1.8 (1.9) times the Standard Model prediction for H arrow right bb and 1.9 (1.2) for H arrow right tau super(+)tau super(-).
In 2004, a full slice of the ATLAS detector was tested for 6 months in the H8 experimental area of the CERN SPS, in the so-called Combined Test Beam, with beams of muons, pions, electrons and photons ...in the range 1 to 350 GeV. Approximately 90 million events were collected, corresponding to a data volume of 4.5 TB. The importance of this exercise was two-fold: for the first time the whole ATLAS software suite was used on fully combined real data. Besides, a novel production infrastructure was employed for the reconstruction of the real data as well as for a massive production of simulated events. This paper is a report on distributed Combined Test Beam Monte Carlo production with and without grid tools. In 2004, Monte Carlo production was started on the CERN LSF batch system and later it was, for the first time, performed on the LCG, with the simulation of about 4 Million events. In 2005, a more light-weight and user friendly system was tested on NorduGrid for the quick production of 210'000 photon events and 680'000 pion, muon and electron events. New Monte Carlo productions are already planed for the year 2006, using the new ATLAS production system
Large-size Resistive Micromegas have been chosen for the upgrade of the forward muon spectrometer of the ATLAS experiment, the New Small Wheel project. These chambers, together with small-strip Thin ...Gap Chambers (sTGC), allow reconstruction of high-momentum muon tracks in a high-radiation environment and provide a robust low-threshold single-muon trigger. A collaboration of seven INFN units built 32 SM1 type chambers, corresponding to one fourth of the total number needed for this upgrade. Each SM1 chamber has a surface of approximately 2 m2 and four sensitive layers. The production was shared among five INFN construction sites and it was completed in fall 2020. The construction methods, as well as the results of the quality tests done on components of the detector and on the assembled chambers, are reported in the present paper.
Muon identification (MUID) and high-momentum measurement accuracy is crucial to fully exploit the physics potential that will be accessible with the ATLAS experiment at the LHC. The muon energy of ...physics interest ranges in a large interval from few GeV, where the b-physics studies dominate the physics program, up to the highest values that could indicate the presence of new physics. The muon detection system of the ATLAS detector is characterized by two high-precision tracking systems, namely the inner detector (ID) and the muon spectrometer, (MS) plus a thick calorimeter that ensures a safe hadron absorption filtering with high-purity muons with energy above 3 GeV. In order to combine the muon tracks reconstructed in the ID and the MS, a MUID object-oriented software package has been developed. The purpose of the MUID procedure is to associate tracks found in the MS with the corresponding ID track and calorimeter information in order to identify muons at their production vertex with optimum parameter resolution. The performance of these two combined systems has been evaluated with Monte Carlo studies using single muons of fixed-transverse momentum and with full physics events.
We have measured the cross section σ(e+e−→π+π−γ) at an energy W=mϕ=1.02 GeV with the KLOE detector at the electron–positron collider DAΦNE. From the dependence of the cross section on the invariant ...mass of the two-pion system, we extract σ(e+e−→π+π−) for the mass range 0.35<s<0.95 GeV2. From this result, we calculate the pion form factor and the hadronic contribution to the muon anomaly, aμ.
The KLOE electromagnetic calorimeter Adinolfi, M; Ambrosino, F; Antonelli, A ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2002, Volume:
482, Issue:
1-2
Journal Article
Peer reviewed
The KLOE detector was designed primarily for the study of CP violation in neutral kaon decays at DAΦNE, the Frascati φ-factory. The detector consists of a tracker and an electromagnetic calorimeter. ...A lead-scintillating-fiber sampling calorimeter satisfies best the requirements of the experiment, providing adequate energy resolution and superior timing accuracy. We describe in the following the construction of the calorimeter, its calibration and how the calorimeter information is used to obtain energy, point of entry and time of the arrival of photons, electrons and charged particles. With e+e− collision data at DAΦNE for an integrated luminosity of some 2pb−1 we find for electromagnetic showers, an energy resolution of 5.7%/E(GeV) and a time resolution of 54/E(GeV) ps. We also present a measurement of efficiency for low energy photons.
Detecting scalars with KLOE Farilla, A.; Kim, W.; Lee-Franzini, J.
Nuclear physics. A,
09/1997, Volume:
623, Issue:
1
Journal Article
Peer reviewed
The KLOE detector is presently under construction at DAΦNE, the Frascati φ-factory, with the aim of studying CP violation in the
K
0
K
0
system. At the design luminosity L=10
33cm
−2s
−1 about 5 × 10
...10 φ-decays will be detected per year: this will be a unique possibility to study in detail the radiative δ decays into scalar mesons
φ → (
f
0,
a
0)
γ, thus helping in establishing the nature of these mesons which is still under debate 1.
Data handling, reconstruction, and simulation for the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
534, Issue:
3
Journal Article
Peer reviewed
Open access
The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φ
factory, and calls for an up-to-date system for data acquisition and processing. In this review of ...the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system.
The KLOE detector is designed primarily for the study of direct CP violation in K
0 decays. The electromagnetic calorimeter, EmC, is a most demanding element of the detector. Two prototypes of the ...EmC (one for the
barrel and one for the
end-cap region) have been built at Frascati and tested at PSI (Switzerland) using beams of electrons, muons and pions of 40 to 290 MeV/
c momentum, and at the Frascati LADON facility using photons of 20 to 80 MeV. We observe excellent linearity from 20 to 290 MeV. The energy resolution is
σ(E)/E ∼ 4.4% / ”E(
GeV)
and the time resolution is ∼ 34 ps/”
E(GeV). We found little dependence on incidence angle and entry position. We also determined that some
π
μ
identification is possible.
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