scholarly journals Alignment of the ATLAS Inner Detector in Run 2

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Hadron Collider ◽  
Time Dependent ◽  
Mechanical Assembly ◽  
Momentum Scale ◽  
Atlas Experiment ◽  
Track Parameter ◽  
Hierarchical Levels ◽  
Detector Geometry ◽  
Long Timescales

AbstractThe performance of the ATLAS Inner Detector alignment has been studied using pp collision data at $$\sqrt{s} = 13\,\hbox {TeV}$$ s = 13 TeV collected by the ATLAS experiment during Run 2 (2015–2018) of the Large Hadron Collider (LHC). The goal of the detector alignment is to determine the detector geometry as accurately as possible and correct for time-dependent movements. The Inner Detector alignment is based on the minimization of track-hit residuals in a sequence of hierarchical levels, from global mechanical assembly structures to local sensors. Subsequent levels have increasing numbers of degrees of freedom; in total there are almost 750,000. The alignment determines detector geometry on both short and long timescales, where short timescales describe movements within an LHC fill. The performance and possible track parameter biases originating from systematic detector deformations are evaluated. Momentum biases are studied using resonances decaying to muons or to electrons. The residual sagitta bias and momentum scale bias after alignment are reduced to less than $$\sim 0.1\hbox { TeV}^{-1}$$ ∼ 0.1 TeV - 1 and $$0.9\times 10^{-3}$$ 0.9 × 10 - 3 , respectively. Impact parameter biases are also evaluated using tracks within jets.

scholarly journals Conditions DataHandling in the Multithreaded ATLAS Framework

2019 ◽  
Vol 214 ◽  
pp. 05031 ◽  
Author(s):  
Charles Leggett ◽  
Illya Shapoval ◽  
Scott Snyder ◽  
Vakho Tsulaia
Keyword(s):  
Time Dependent ◽  
Multiple Events ◽  
Atlas Experiment ◽  
Event Time ◽  
Detector Geometry

In preparation for Run 3 of the LHC, the ATLAS experiment is migrating its offline software to use a multithreaded framework, which will allow multiple events to be processed simultaneously. This implies that the handling of non-event, time-dependent (conditions) data, such as calibrations and geometry, must also be extended to allow for multiple versions of such data to exist simultaneously. This has now been implemented as part of the new ATLAS framework. The detector geometry is included in this scheme by having sets of time-dependent displacements on top of a static base geometry.

Introduction

2018 ◽  
Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen
Keyword(s):  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Degrees Of Freedom ◽  
State Level ◽  
Boltzmann Distribution ◽  
Theoretical Description ◽  
Time Dependent ◽  
Nuclear Dynamics ◽  
Molecular Reaction ◽  
Oppenheimer Approximation

This introductory chapter considers first the relation between molecular reaction dynamics and the major branches of physical chemistry. The concept of elementary chemical reactions at the quantized state-to-state level is discussed. The theoretical description of these reactions based on the time-dependent Schrödinger equation and the Born–Oppenheimer approximation is introduced and the resulting time-dependent Schrödinger equation describing the nuclear dynamics is discussed. The chapter concludes with a brief discussion of matter at thermal equilibrium, focusing at the Boltzmann distribution. Thus, the Boltzmann distribution for vibrational, rotational, and translational degrees of freedom is discussed and illustrated.

scholarly journals Implementation of dimensional management methodology and optimisation algorithms for pre-drilled hinge line interfaces of critical aero assemblies – A case study

2020 ◽  
pp. 095440542097810
Author(s):  
Konstantinos C Bacharoudis ◽  
David Bainbridge ◽  
Alison Turner ◽  
Atanas A Popov ◽  
Svetan M Ratchev
Keyword(s):  
Degrees Of Freedom ◽  
Engineering Problem ◽  
Hole Diameter ◽  
Design Stage ◽  
Assembly Process ◽  
Mechanical Assembly ◽  
Hinge Line ◽  
Management Procedure ◽  
Dimensional Management ◽  
Optimisation Algorithms

A dimensional management procedure is developed and implemented in this work to deal with the identification of the optimum hole diameter that needs to be pre-drilled in order to successfully join two subassemblies in a common hinge line interface when most of the degrees of freedom of each subassembly have already been constrained. Therefore, an appropriate measure is suggested that considers the assembly process and permits the application of optimisation algorithms for the identification of the optimum hole diameter. The complexity of the mechanical subassemblies requires advanced 3D tolerance analysis techniques to be implemented and the matrix method was adopted. The methodology was demonstrated for an industrial, aerospace engineering problem, that is, the assembly of the joined wing configuration of the RACER compound rotorcraft of AIRBUS Helicopter and the necessary tooling needed to build the assembly. The results indicated that hinge line interfaces can be pre-opened at a sufficiently large size and thus, accelerate the assembly process whilst the suggested methodology can be used as a decision-making tool at the design stage of this type of mechanical assembly.

scholarly journals THE DYNAMIC RESPONSE OF OFFSHORE STRUCTURES TO TIME-DEPENDENT FORCES

1964 ◽  
Vol 1 (9) ◽  
pp. 29
Author(s):  
William S. Gaither ◽  
David P. Billington
Keyword(s):  
Degrees Of Freedom ◽  
Wind Waves ◽  
Offshore Structures ◽  
Time Dependent ◽  
Wave Forces ◽  
Ocean Bottom ◽  
Single Wave ◽  
Single Degree Of Freedom ◽  
The Many ◽  
Floating Objects

This paper is addressed to the problem of structural behavior in an offshore environment, and the application of a more rigorous analysis for time-dependent forces than is currently used. Design of pile supported structures subjected to wave forces has, in the past, been treated in two parts; (1) a static analysis based on the loading of a single wave, and (2) a dynamic analysis which sought to determine the resonant frequency by assuming that the structure could be approximated as a single-degree-of-freedom system. (Ref. 4 and 6) The behavior of these structures would be better understood if the dynamic nature of the loading and the many degrees of freedom of the system were included. A structure which is built in the open ocean is subjected to periodic forces due to wind, waves, floating objects, and due occasionally to machinery mounted on the structure. To resist motion, the structure relies on the stiffness of the elements from which it is built and the restraints of the ocean bottom into which the supporting legs are driven.

scholarly journals The Detector Control System for the magnetic field sensors in New Small Wheel phase I upgrade of ATLAS detector

2021 ◽  
Vol 2105 (1) ◽  
pp. 012026
Author(s):  
Stamatios Tzanos
Keyword(s):  
Magnetic Field ◽  
Control System ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Magnetic Field Sensors ◽  
Atlas Experiment ◽  
Data Rates ◽  
Level 1 ◽  
The Magnetic Field ◽  
Detector Control System

Abstract In conjunction with the High Luminosity upgrade of the Large Hadron Collider accelerator at CERN, the ATLAS detector is also undergoing an upgrade to handle the significantly higher data rates. The muon end-cap system upgrade in ATLAS, lies with the replacement of the Small Wheel. The New Small Wheel (NSW) is expected to combine high tracking precision with upgraded information for the Level-1 trigger. To accomplish this, small Thin Gap Chamber (sTGC) and MicroMegas detector technologies are being deployed. Due to their installation location in ATLAS, the effects of Barrel Toroid and End-Cap Toroid magnets on NSW must be measured. For the final experiment at ATLAS, each sTGC large double wedge will be equipped with magnetic field Hall effect sensors to monitor the magnetic field near the NSW. The readout is done with an Embedded Local Monitor Board (ELMB) called MDT DCS Module (MDM). For the integration of this hardware in the experiment, first, a detector control system was developed to test the functionality of all sensors before their installation on the detectors. Subsequently, another detector control system was developed for the commissioning of the sensors. Finally, a detector control system based on the above two is under development for the expert panels of ATLAS experiment. In this paper, the sensor readout, the connectivity mapping and the detector control systems will be presented.

Diffraction and photon exchange processes at the LHC and parton saturation

2020 ◽  
Vol 35 (08) ◽  
pp. 2030004 ◽  
Author(s):  
Christophe Royon ◽  
Cristian Baldenegro
Keyword(s):  
New York ◽  
Degrees Of Freedom ◽  
National Laboratory ◽  
Hadron Collider ◽  
Brookhaven National Laboratory ◽  
Forward Physics ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Proton Structure ◽  
Exchange Processes

We present a review of the recent theoretical and experimental developments related to the field of diffraction, parton saturation, and forward physics. We first discuss our present understanding of the proton structure in terms of quarks and gluons, the degrees of freedom of quantum chromodynamics. We then focus on some of the main results on diffraction at the HERA electron–proton collider in DESY, Germany, at the Tevatron proton–antiproton collider at Fermilab, Batavia, US, and at the CERN Large Hadron Collider (LHC) proton–proton and nucleus–nucleus collider, which is located in Geneva, Switzerland. We also present a selected amount of results on diffraction and photon exchanges that can be done at the LHC experiments and at a future Electron Ion Collider (EIC) to be built in the US at Brookhaven National Laboratory, New York.

Scale-invariant Characteristics of Forgetting: Toward a Unifying Account of Hippocampal Forgetting across Short and Long Timescales

2020 ◽  
Vol 32 (3) ◽  
pp. 386-402
Author(s):  
Talya Sadeh ◽  
Yoni Pertzov
Keyword(s):  
Time Dependent ◽  
Scale Invariant ◽  
Relational Information ◽  
Recent Advances ◽  
Growing Body ◽  
Neural Underpinnings ◽  
Important Extension ◽  
Long Timescales ◽  
Prevailing View

After over 100 years of relative silence in the cognitive literature, recent advances in the study of the neural underpinnings of memory—specifically, the hippocampus—have led to a resurgence of interest in the topic of forgetting. This review draws a theoretically driven picture of the effects of time on forgetting of hippocampus-dependent memories. We review evidence indicating that time-dependent forgetting across short and long timescales is reflected in progressive degradation of hippocampal-dependent relational information. This evidence provides an important extension to a growing body of research accumulated in recent years, showing that—in contrast to the once prevailing view that the hippocampus is exclusively involved in memory and forgetting over long timescales—the role of the hippocampus also extends to memory and forgetting over short timescales. Thus, we maintain that similar rules govern not only remembering but also forgetting of hippocampus-dependent information over short and long timescales.

scholarly journals Run Control Software For The Upgrade Of The Atlas Muon To Central Trigger Processor Interface (MUCTPI)

2019 ◽  
Vol 214 ◽  
pp. 01034
Author(s):  
Ralf Spiwoks ◽  
Aaron Armbruster ◽  
German Carrillo-Montoya ◽  
Magda Chelstowska ◽  
Patrick Czodrowski ◽  
...  
Keyword(s):  
Hadron Collider ◽  
Programmable Logic ◽  
Trigger System ◽  
Control Software ◽  
Atlas Experiment ◽  
Arm Processor ◽  
Level 1 ◽  
On Chip ◽  
Control Application ◽  
Processor Cores

The Muon to Central Trigger Processor Interface (MUCTPI) of the ATLAS experiment at the Large Hadron Collider(LHC) at CERN is being upgraded for the next run of the LHC in order to use optical inputs and to provide full-precision information for muon candidates to the topological trigger processor (L1TOPO) of the Level-1 trigger system. The new MUCTPI is implemented as a single ATCA blade with high-end processing FPGAs which eliminate doublecounting of muon candidates in overlapping regions, send muon candidates to L1TOPO, and muon multiplicities tothe Central Trigger Processor (CTP), as well as readout data to the data acquisition system of the experiment. A Xilinx Zynq System-on-Chip (SoC) with a programmable logic part and a processor part is used for the communication to the processing FPGAs and the run control system. The processor part, based on ARM processor cores, is running embedded Linux prepared using the framework of the Linux Foundation's Yocto project. The ATLAS run control software was ported to the processor part and a run control application was developed which receives, at configuration, all data necessary for the overlap handling and candidate counting of the processing FPGAs. During running, the application provides ample monitoring of the physics data and of the operation of the hardware. *

scholarly journals Effective 1D Time-Dependent Schrödinger Equations for 3D Geometrically Correlated Systems

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3033
Author(s):  
Devashish Pandey ◽  
Xavier Oriols ◽  
Guillermo Albareda
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Longitudinal Direction ◽  
Time Dependent ◽  
Ab Initio Molecular Dynamics ◽  
Quantitative Accuracy ◽  
Dimensional Simulation ◽  
Transport Problems ◽  
Computational Resources

The so-called Born–Huang ansatz is a fundamental tool in the context of ab-initio molecular dynamics, viz., it allows effectively separating fast and slow degrees of freedom and thus treating electrons and nuclei with different mathematical footings. Here, we consider the use of a Born–Huang-like expansion of the three-dimensional time-dependent Schrödinger equation to separate transport and confinement degrees of freedom in electron transport problems that involve geometrical constrictions. The resulting scheme consists of an eigenstate problem for the confinement degrees of freedom (in the transverse direction) whose solution constitutes the input for the propagation of a set of coupled one-dimensional equations of motion for the transport degree of freedom (in the longitudinal direction). This technique achieves quantitative accuracy using an order less computational resources than the full dimensional simulation for a typical two-dimensional geometrical constriction and upto three orders for three-dimensional constriction.

scholarly journals TEV NEUTRINO PHYSICS AT THE LARGE HADRON COLLIDER

2009 ◽  
Vol 24 (18n19) ◽  
pp. 3286-3296 ◽  
Author(s):  
ZHI-ZHONG XING
Keyword(s):  
Neutrino Physics ◽  
Large Hadron Collider ◽  
Particle Physics ◽  
Degrees Of Freedom ◽  
Neutrino Oscillations ◽  
Hadron Collider ◽  
Higgs Bosons ◽  
Type I ◽  
Seesaw Mechanism ◽  
Majorana Neutrinos

I argue that TeV neutrino physics might become an exciting frontier of particle physics in the era of the Large Hadron Collider (LHC). The origin of non-zero but tiny masses of three known neutrinos is probably related to the existence of some heavy degrees of freedom, such as heavy Majorana neutrinos or heavy Higgs bosons, via a TeV-scale seesaw mechanism. I take a few examples to illustrate how to get a balance between theoretical naturalness and experimental testability of TeV seesaws. Besides possible collider signatures at the LHC, new and non-unitary CP-violating effects are also expected to show up in neutrino oscillations for type-I, type-(I+II) and type-III seesaws at the TeV scale.

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