scholarly journals Recent minimum-bias measurements by ATLAS

2019 ◽  
Vol 208 ◽  
pp. 05001
Author(s):  
Krzysztof W. Wózniak
Keyword(s):  
Large Hadron Collider ◽  
Cross Section ◽  
Hadron Collider ◽  
Cosmic Ray ◽  
Inelastic Cross Section ◽  
Minimum Bias ◽  
Pp Collisions ◽  
Underlying Event ◽  
Atlas Experiment

The Large Hadron Collider provides collisions of protons and nuclei at the highest energies available in the laboratory. A variety of recent results for minimum-bias pp, p+Pb and Pb+Pb collisions obtained by the ATLAS experiment is presented. For pp collisions they include the total and inelastic cross section, properties of minimum-bias events, underlying event characteristics and measurements of diffractive processes. The results for p+Pb and Pb+Pb collisions that are relevant for cosmic ray studies are also presented.

scholarly journals Search for Heavy Higgs Bosons with the ATLAS Detector

2018 ◽  
Vol 46 ◽  
pp. 1860056
Author(s):  
Jana Schaarschmidt
Keyword(s):  
Large Hadron Collider ◽  
Cross Section ◽  
Production Cross Section ◽  
Production Cross ◽  
Hadron Collider ◽  
New Physics ◽  
Atlas Detector ◽  
Higgs Bosons ◽  
Final States ◽  
Atlas Experiment

The ATLAS experiment at the Large Hadron Collider performed searches for heavy Higgs bosons, whose presence would establish the existance of new physics. Searches for charged and neutral Higgs bosons are carried out using 8 or 13 TeV data for various production modes and in many different final states. No deviations from Standard Model expectations are observed. Exclusions limits are set on the production cross section and on parameters in various benchmark models.

scholarly journals Inclusive $$\text {J}/\psi $$ production at midrapidity in pp collisions at $$\sqrt{s} = 13$$ TeV

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
G. Aglieri Rinella ◽  
M. Agnello ◽  
...  
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Decay Channel ◽  
Production Cross ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Electromagnetic Calorimeter ◽  
Minimum Bias ◽  
Pp Collisions ◽  
Evaporation Models

AbstractWe report on the inclusive $$\text {J}/\psi $$ J / ψ production cross section measured at the CERN Large Hadron Collider in proton–proton collisions at a center-of-mass energy $$\sqrt{s}~=~13$$ s = 13  TeV. The $$\text {J}/\psi $$ J / ψ mesons are reconstructed in the $$\text {e}^{+}\text {e}^{-}$$ e + e - decay channel and the measurements are performed at midrapidity ($$|y|<0.9$$ | y | < 0.9 ) in the transverse-momentum interval $$0<p_{\mathrm{T}} <40$$ 0 < p T < 40  GeV/$$c$$ c , using a minimum-bias data sample corresponding to an integrated luminosity $$L_{\text {int}} = 32.2~\text {nb}^{-1}$$ L int = 32.2 nb - 1 and an Electromagnetic Calorimeter triggered data sample with $$L_{\text {int}} = 8.3~\mathrm {pb}^{-1}$$ L int = 8.3 pb - 1 . The $$p_{\mathrm{T}}$$ p T -integrated $$\text {J}/\psi $$ J / ψ production cross section at midrapidity, computed using the minimum-bias data sample, is $$\text {d}\sigma /\text {d}y|_{y=0} = 8.97\pm 0.24~(\text {stat})\pm 0.48~(\text {syst})\pm 0.15~(\text {lumi})~\mu \text {b}$$ d σ / d y | y = 0 = 8.97 ± 0.24 ( stat ) ± 0.48 ( syst ) ± 0.15 ( lumi ) μ b . An approximate logarithmic dependence with the collision energy is suggested by these results and available world data, in agreement with model predictions. The integrated and $$p_{\mathrm{T}}$$ p T -differential measurements are compared with measurements in pp collisions at lower energies and with several recent phenomenological calculations based on the non-relativistic QCD and Color Evaporation models.

scholarly journals The Thermosiphon Cooling System of the ATLAS Experiment at the CERN Large Hadron Collider

2015 ◽  
Vol 13 (4) ◽  
pp. 511-521 ◽  
Author(s):  
M. Battistin ◽  
S. Berry ◽  
A. Bitadze ◽  
P. Bonneau ◽  
J. Botelho-Direito ◽  
...  
Keyword(s):  
Large Hadron Collider ◽  
Cooling System ◽  
Hadron Collider ◽  
Full Scale ◽  
Small Scale ◽  
Primary Coolant ◽  
Cern Large Hadron Collider ◽  
Atlas Experiment ◽  
Silicon Sensors ◽  
Effects Of Radiation

Abstract The silicon tracker of the ATLAS experiment at CERN Large Hadron Collider will operate around –15°C to minimize the effects of radiation damage. The present cooling system is based on a conventional evaporative circuit, removing around 60 kW of heat dissipated by the silicon sensors and their local electronics. The compressors in the present circuit have proved less reliable than originally hoped, and will be replaced with a thermosiphon. The working principle of the thermosiphon uses gravity to circulate the coolant without any mechanical components (compressors or pumps) in the primary coolant circuit. The fluorocarbon coolant will be condensed at a temperature and pressure lower than those in the on-detector evaporators, but at a higher altitude, taking advantage of the 92 m height difference between the underground experiment and the services located on the surface. An extensive campaign of tests, detailed in this paper, was performed using two small-scale thermosiphon systems. These tests confirmed the design specifications of the full-scale plant and demonstrated operation over the temperature range required for ATLAS. During the testing phase the system has demonstrated unattended long-term stable running over a period of several weeks. The commissioning of the full scale thermosiphon is ongoing, with full operation planned for late 2015.

scholarly journals The Controls and Configuration Software of the ATLAS Data Acquisition System: evolution towards LHC Run 3

2021 ◽  
Vol 251 ◽  
pp. 04019
Author(s):  
Andrei Kazarov ◽  
Adrian Chitan ◽  
Andrei Kazymov ◽  
Alina Corso-Radu ◽  
Igor Aleksandrov ◽  
...  
Keyword(s):  
Large Hadron Collider ◽  
Data Acquisition ◽  
New Technologies ◽  
Dead Time ◽  
Hadron Collider ◽  
Data Acquisition System ◽  
Configuration Software ◽  
Atlas Experiment ◽  
Atlas Data ◽  
Software Updates

The ATLAS experiment at the Large Hadron Collider (LHC) operated very successfully in the years 2008 to 2018, in two periods identified as Run 1 and Run 2. ATLAS achieved an overall data-taking efficiency of 94%, largely constrained by the irreducible dead-time introduced to accommodate the limitations of the detector read-out electronics. Out of the 6% dead-time only about 15% could be attributed to the central trigger and DAQ system, and out of these, a negligible fraction was due to the Control and Configuration subsystem. Despite these achievements, and in order to improve even more the already excellent efficiency of the whole DAQ system in the coming Run 3, a new campaign of software updates was launched for the second long LHC shutdown (LS2). This paper presents, using a few selected examples, how the work was approached and which new technologies were introduced into the ATLAS Control and Configuration software. Despite these being specific to this system, many solutions can be considered and adapted to different distributed DAQ systems.

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