HERAFitter Alekhin, S.; Behnke, O.; Belov, P. ...
The European physical journal. C, Particles and fields,
07/2015, Letnik:
75, Številka:
7
Journal Article
Recenzirano
Odprti dostop
HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum ...Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton–proton deep inelastic scattering and proton–proton (proton–antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodological options for carrying out PDF fits and plotting tools to help to visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Technical design of the phase I Mu3e experiment Arndt, K.; Augustin, H.; Baesso, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2021, Letnik:
1014
Journal Article
Recenzirano
Odprti dostop
The Mu3e experiment aims to find or exclude the lepton flavour violating decay μ→eee at branching fractions above 10−16. A first phase of the experiment using an existing beamline at the Paul ...Scherrer Institute (PSI) is designed to reach a single event sensitivity of 2⋅10−15. We present an overview of all aspects of the technical design and expected performance of the phase I Mu3e detector. The high rate of up to 108 muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.
The hit combinatorial problem is a main challenge for track reconstruction and triggering at high rate experiments. This simplification is possible since track uncertainties are solely determined by ...MS if high precision spatial information is provided. Fitting of hit-triplets is especially simple for tracking detectors in solenoidal magnetic fields. The over-constrained 3D-triplet method provides a complete set of track parameters and is robust against fake hit combinations. The triplet method is ideally suited for pixel detectors where hits can be treated as 3D-space points. In this paper tracking performance studies for full-scale pixel detectors, including their optimisation for 3D-triplet tracking, are presented. The results obtained for different types of tracker geometries and different reconstruction methods are compared. The potential of reducing the number of tracking layers and - along with that - the material budget using this new tracking concept is discussed. The possibility of using 3D-triplet tracking for triggering and fast online reconstruction is highlighted.
High voltage CMOS pixel sensors will be or are proposed to be used in several particle physics experiments for particle tracking like Mu3e experiment. ATLASPIX3 is the first full reticle size ...monolithic HVCMOS sensor for construction of multi-chip modules. The specifications for the use case have been taken from ATLAS pixel upgrade in fifth layer where it was a candidate for. The size of the chip is 2.0×2.1 cm2 with periphery at one side which makes the chip 3-side buttable. ATLASPIX3 has been implemented in a standard 180 nm HVCMOS process. Each pixel has an area of 150×50μm2 and contains a large charge collecting electrode implemented as deep n-well. The depleted volume around the n-well is enlarged by a high voltage bias and the usage of higher resistivity substrate. The readout electronics supports both triggered and triggerless readout with zero-suppression. ATLASPIX3 could be used for the construction of CMOS modules for particle tracking in experiments where high time resolution, high radiation tolerance, low power and low material budget are required. In the design phase, special attention has been paid to decreasing timing differences between pixels and the rate capability of the readout.
The radiation pattern within high energy quark- and gluon-initiated jets (jet substructure) is used extensively as a precision probe of the strong force as well as an environment for optimizing event ...generators with numerous applications in high energy particle and nuclear physics. Looking at electron-proton collisions is of particular interest as many of the complications present at hadron colliders are absent. A detailed study of modern jet substructure observables, jet angularities, in electron-proton collisions is presented using data recorded using the H1 detector at HERA. The measurement is unbinned and multi-dimensional, using machine learning to correct for detector effects. All of the available reconstructed object information of the respective jets is interpreted by a graph neural network, achieving superior precision on a selected set of jet angularities. Training these networks was enabled by the use of a large number of GPUs in the Perlmutter supercomputer at Berkeley Lab. The particle jets are reconstructed in the laboratory frame, using the kT jet clustering algorithm. Results are reported at high transverse momentum transfer Q2>150GeV2, and inelasticity 0.2<y<0.7. The analysis is also performed in sub-regions of Q2, thus probing scale dependencies of the substructure variables. The data are compared with a variety of predictions and point towards possible improvements of such models.
Abstract
The fast reconstruction of charged particle tracks with high efficiency and track quality is an essential part of the online data selection for the ATLAS experiment at the High Luminosity ...LHC.
Dedicated custom designed hardware boards and software simulations have been developed to assess the feasibility of a Hardware Tracking Trigger (HTT) system.
The Pattern Recognition Mezzanine (PRM), as part of the HTT system, has been designed to recognize track candidates in silicon detectors with Associative Memory ASICs and to select and reconstruct tracks using linearized algorithms implemented in an Intel Stratix 10 MX FPGA.
The highly parallelized FPGA design makes extensive use of the integrated High-Bandwidth-Memory.
In this paper, the FPGA design for the PRM board is presented. Its functionalities have been verified in both simulations and hardware tests on an Intel Stratix 10 MX development kit.
The Mu3e experiment is searching for the charged lepton flavour violating decay\break μ+→e+e−e+, aiming for an ultimate sensitivity of one in 1016 decays. In an environment of up to 109 muon decays ...per second the detector needs to provide precise vertex, time and momentum information to suppress accidental and physics background. The detector consists of cylindrical layers of 50μm thin High Voltage Monolithic Active Pixel Sensors (HV-MAPS) placed in a 1T magnetic field. The measurement of the trajectories of the decay particles allows for a precise vertex and momentum reconstruction. Additional layers of fast scintillating fibre and tile detectors provide sub-nanosecond time resolution. The MuPix8 chip is the first large scale prototype, proving the scalability of the HV-MAPS technology. It is produced in the AMS aH18 180nm HV-CMOS process. It consists of three sub-matrices, each providing an untriggered datastream of more than 10MHits/s. The latest results from laboratory and testbeam characterisation are presented, showing an excellent performance with efficiencies >99.6% and a time resolution better than 10ns achieved with time walk correction.
Monolithic active pixel sensors (MAPS) based on commercial high-voltage CMOS processes are an exciting technology that is considered as an option for the ATLAS Inner Tracker upgrade. Particles are ...detected using deep n-wells on a p-type substrate as sensor diodes with the depleted region extending into the silicon bulk. With readout electronics and sensor integrated on the same device, the detector complexity and the material budget are greatly reduced. The ATLASPix1 pixel sensor prototype is a large-scale MAPS prototype that implements the full readout chain on a single physical chip. It features a large in-pixel sensor electrode and is produced using the ams aH18 high voltage technology. Three pixel matrices with different readout architectures, triggered and untriggered, and pixel designs are implemented. We show the performance of one of the pixel matrix variants for samples irradiated up to 1015 1MeV meq/cm2.
For the planned high luminosity upgrade of the Large Hadron Collider, aiming to increase the instantaneous luminosity to 5 x 10 super(34)cm super(-2)s super(-1), the implementation of a first level ...track trigger has been proposed. This trigger could be installed in the year similar to 2021 along with the complete renewal of the ATLAS inner detector. The fast readout of the hit information from the Inner Detector is considered as the main challenge of such a track trigger. Different concepts for the implementation of a first level trigger are currently studied within the ATLAS collaboration. The so called "Self Seeded" track trigger concept exploits fast frontend filtering algorithms based on cluster size reconstruction and fast vector tracking to select hits associated to high momentum tracks. Simulation studies have been performed and results on efficiencies, purities and trigger rates are presented for different layouts.
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