scholarly journals Configuration and performance of the ATLAS b-jet triggers in Run 2

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Heavy Ion ◽  
Correction Factors ◽  
Online Environment ◽  
Conditional Efficiency ◽  
Systematic Uncertainties ◽  
Pile Up ◽  
Order Of Magnitude ◽  
And Performance ◽  
First Time

AbstractSeveral improvements to the ATLAS triggers used to identify jets containing b-hadrons (b-jets) were implemented for data-taking during Run 2 of the Large Hadron Collider from 2016 to 2018. These changes include reconfiguring the b-jet trigger software to improve primary-vertex finding and allow more stable running in conditions with high pile-up, and the implementation of the functionality needed to run sophisticated taggers used by the offline reconstruction in an online environment. These improvements yielded an order of magnitude better light-flavour jet rejection for the same b-jet identification efficiency compared to the performance in Run 1 (2011–2012). The efficiency to identify b-jets in the trigger, and the conditional efficiency for b-jets that satisfy offline b-tagging requirements to pass the trigger are also measured. Correction factors are derived to calibrate the b-tagging efficiency in simulation to match that observed in data. The associated systematic uncertainties are substantially smaller than in previous measurements. In addition, b-jet triggers were operated for the first time during heavy-ion data-taking, using dedicated triggers that were developed to identify semileptonic b-hadron decays by selecting events with geometrically overlapping muons and jets.

scholarly journals Characterization of Irradiated Boron, Carbon-Enriched and Gallium Si-on-Si Wafer Low Gain Avalanche Detectors

Instruments ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Lucía Castillo García ◽  
Evangelos Leonidas Gkougkousis ◽  
Chiara Grieco ◽  
Sebastian Grinstein
Keyword(s):  
Performance Studies ◽  
Hadron Collider ◽  
Electrical Characterization ◽  
Full Characterization ◽  
Silicon Sensors ◽  
Pile Up ◽  
Before And After ◽  
And Performance ◽  
Si Wafer

Low Gain Avalanche Detectors (LGADs) are n-on-p silicon sensors with an extra doped p-layer below the n-p junction which provides signal amplification. The moderate gain of these sensors, together with the relatively thin active region, provides excellent timing performance for Minimum Ionizing Particles (MIPs). To mitigate the effect of pile-up during the High-Luminosity Large Hadron Collider (HL-LHC) era, both ATLAS and CMS experiments will install new detectors, the High-Granularity Timing Detector (HGTD) and the End-Cap Timing Layer (ETL), that rely on the LGAD technology. A full characterization of LGAD sensors fabricated by Centro Nacional de Microelectrónica (CNM), before and after neutron irradiation up to 1015 neq/cm2, is presented. Sensors produced in 100 mm Si-on-Si wafers and doped with boron and gallium, and also enriched with carbon, are studied. The results include their electrical characterization (I-V, C-V), bias voltage stability and performance studies with the Transient Current Technique (TCT) and a Sr-90 radioactive source setup.

scholarly journals Thermal production of sexaquarks in heavy-ion collisions

2021 ◽  
Vol 36 (25) ◽  
Author(s):  
David Blaschke ◽  
Larissa Bravina ◽  
Kyrill Bugaev ◽  
Glennys R. Farrar ◽  
Boris Grinyuk ◽  
...  
Keyword(s):  
Dark Matter ◽  
Heavy Ion Collisions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Dark Matter Candidate ◽  
Ion Collisions ◽  
Great Relevance ◽  
Age Of The Universe ◽  
First Time ◽  
The Universe

We present new results on the thermal production yield of a hypothetical state made of six quarks [Formula: see text] assuming its production in heavy-ion collisions at the CERN Large Hadron Collider (LHC). A state with this quark content and mass low enough to be stable against decay in timescales of the order of the age of the Universe has been hypothesized by one of us (G. Farrar) and has been discussed as a possible dark matter candidate. In this work, we address for the first time the thermal production rate that can be expected for this state in heavy-ion collisions at colliders. For this estimate we use a thermal model which has been shown to describe accurately the production of hadrons and nuclei in heavy-ion collisions at LHC energy. This estimate is of great relevance for sexaquark searches at colliders as well as for its consideration as a dark matter candidate and for the composition of neutron stars.

scholarly journals Operation and performance of the ATLAS semiconductor tracker in LHC Run 2

2022 ◽  
Vol 17 (01) ◽  
pp. P01013
Author(s):  
Georges Aad ◽  
Brad Abbott ◽  
Dale Charles Abbott ◽  
Adam Abed Abud ◽  
Kira Abeling ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Proton Collision ◽  
Original Design ◽  
Proton Proton ◽  
Pile Up ◽  
Proton Proton Collision ◽  
And Performance ◽  
Full Depletion ◽  
The Impact ◽  
Integrated Luminosity

Abstract The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015–2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb-1 to the ATLAS experiment at a centre-of-mass proton-proton collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.

scholarly journals Heavy-ion physics with the ALICE experiment at the CERN Large Hadron Collider

2012 ◽  
Vol 370 (1961) ◽  
pp. 917-932 ◽  
Author(s):  
J. Schukraft
Keyword(s):  
Large Hadron Collider ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Alice Experiment ◽  
Proton Proton ◽  
Heavy Ion Physics ◽  
Cern Large Hadron Collider ◽  
Ion Collisions ◽  
And Performance

After close to 20 years of preparation, the dedicated heavy-ion experiment A Large Ion Collider Experiment (ALICE) took first data at the CERN Large Hadron Collider (LHC) accelerator with proton collisions at the end of 2009 and with lead nuclei at the end of 2010. After a short introduction into the physics of ultra-relativistic heavy-ion collisions, this article recalls the main design choices made for the detector and summarizes the initial operation and performance of ALICE. Physics results from this first year of operation concentrate on characterizing the global properties of typical, average collisions, both in proton–proton (pp) and nucleus–nucleus reactions, in the new energy regime of the LHC. The pp results differ, to a varying degree, from most quantum chromodynamics-inspired phenomenological models and provide the input needed to fine tune their parameters. First results from Pb–Pb are broadly consistent with expectations based on lower energy data, indicating that high-density matter created at the LHC, while much hotter and larger, still behaves like a very strongly interacting, almost perfect liquid.

“Little Trio” for clarinet, bassoon and piano

2018 ◽  
pp. 75-79
Author(s):  
N. Yakovchuk
Keyword(s):  
Chamber Music ◽  
Instrumental Music ◽  
Instrumental Ensemble ◽  
Interesting Phenomenon ◽  
Theoretical Understanding ◽  
Classical Traditions ◽  
And Performance ◽  
Instrumental Ensembles ◽  
Written Compositions ◽  
First Time

The chamber-instrumental ensemble music in the Ukrainian musical culture of the last third of the 20th and the beginning of the 21st centuries occupies one of the leading places and is characterized by powerful processes in its development. Such circumstances caused the Ukrainian musicologist interests to the problems of chamber-instrumental music creativity and performance. There are appeared researches in the field of theory, history and performance problems covering the most important questions like chamber music definitions, specific genre issues, the growing function of piano in the Ukrainian chamber music, the increasing questions of technique and timbre importance of modern instrumental ensembles. In the significant multifaceted creative work of contemporary Ukrainian composer, Oleksandr Yakovchuk, the genre of chamber instrumental ensemble music represents a complex and interesting phenomenon. Original and skillfully written compositions reflect artistic world of the composer of postmodern time and gained recognition in music life of Ukraine and beyond. These works are highly appreciated in performing practice of our days. The purpose of the article is to analyze the work — “Little Trio” for clarinet, bassoon and piano (1980), which has the signs of neoclassical tendency in the composer’s style. The methodological basis of this research is a comprehensive approach in theoretical understanding of the subject of research (the methods of textology, source study as well as the method of interviewing the author were used). The scientific novelty of this article is in the priority of its main provisions, since the “Little Trio” entered the scientific circulation for the first time. The three-movement “Little Trio” (1980) is notable for the light feeling of timbre colours and the shape clarity. The Ist movement — Allegretto giocoso — is written in a sonata form following all classical traditions. Quite interesting are the two monologues of clarinet and bassoon from the IInd movement, they represent very modern line in Ukrainian chamber music — the possibility of sincere confession which comes through the solo cadence. In the IIIrd movement, the composer took advantage from the folk Ukrainian dance “hopak” using the rhythm of it and creating dance character of the Final.

Do Accounting Faculty Characteristics Impact CPA Exam Performance? An Investigation of Nearly 700,000 Examinations

2015 ◽  
Vol 31 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Dennis M. Bline ◽  
Stephen Perreault ◽  
Xiaochuan Zheng
Keyword(s):  
Exam Performance ◽  
Faculty Research ◽  
Pass Rates ◽  
Accounting Faculty ◽  
Research And Teaching ◽  
Faculty Characteristics ◽  
Cpa Exam ◽  
Faculty Research Productivity ◽  
And Performance ◽  
First Time

ABSTRACT While many colleges and universities publicize CPA examination pass rates as evidence of having a high-quality accounting program, some have questioned whether program-specific characteristics are legitimate predictors of examination success. To examine this issue, we empirically investigate the link between accounting faculty characteristics and performance on the CPA examination. We examine the results from nearly 700,000 first-time exam sittings taken during the period 2005–2013 and find that faculty research and teaching specialization has a significant impact on CPA exam performance. That is, when a program has a relatively higher percentage of accounting faculty with expertise in a particular content area tested on the exam (e.g., auditing), graduates achieve higher scores on the related exam section (e.g., AUD). We also find that faculty research productivity and CPA certification status are positively related to candidate exam performance. We believe these results contribute to the existing literature on the determinants of CPA exam success and also provide important insights to those responsible for accounting faculty staffing and development.

Detection and Quantification of 7-Hydroxydehydroepiandrosterone Epimers in Three Body Fluids

2002 ◽  
Vol 67 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Richard Hampl ◽  
Martin Hill ◽  
Luboslav Stárka
Keyword(s):  
Healthy Subjects ◽  
Serum Levels ◽  
Body Fluids ◽  
Gas Chromatography Mass Spectrometry ◽  
Specific Radioimmunoassay ◽  
Order Of Magnitude ◽  
Three Body ◽  
First Time ◽  
Nanomolar Range ◽  
Detection And Quantification

3β,7α-Dihydroxyandrost-5-en-17-one (1) (7α-OH-DHEA) and its 7β-hydroxy epimer 2 (7β-OH-DHEA) - 7α- and 7β-hydroxydehydroepiandrosterone - were detected and quantified in three human body fluids: in blood serum, saliva and ejaculate. Specific radioimmunoassay and gas chromatography-mass spectrometry have been used. For the first time the data on changes of these dehydroepiandrosterone metabolites are reported for a representative group of healthy subjects of both sexes (172 females and 217 males) during the life span. The serum levels of both 7-hydroxydehydroepiandrosterone epimers in serum and also in semen were in the low nanomolar range, while concentrations by one order of magnitude lower were found in saliva, but still within the detection limit. The results will serve as a basis for comparative studies of 7-hydroxydehydroepiandrosterone levels under various pathophysiological conditions, with a particular respect to autoimmune disorders.

scholarly journals Study of multicharged heavy ion generation from CO2 laser-produced plasma

1996 ◽  
Vol 14 (3) ◽  
pp. 347-368 ◽  
Author(s):  
V.Yu. Baranov ◽  
K.N. Makarov ◽  
V.C. Roerich ◽  
Yu.A. Satov ◽  
A.N. Starostin ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Laser System ◽  
Heavy Ion ◽  
Ion Source ◽  
Lead Ion ◽  
Ion Generation ◽  
Wavelength Radiation ◽  
Laser Heated ◽  
Work Done ◽  
Power Densities

The results of lead ion generation with charge state from Pb10+ to Pb35+ from laser-heated plasma are presented. CO2 lasers producing 10.6-μm wavelength radiation at power densities in the range 4.1011-6.1014 W/cm2 in TBKI and CERN were used. Results of detailed numerical simulations presented in the paper are in good agreement with the experimental data. Work done in collaboration with CERN, ITEP, and TBKI was aimed at the specification of requirements for a laser system that will be able to drive an ion source for the hadron collider (LHC) at CERN.

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