These proceedings present the method and performance of primary vertex reconstruction at the ATLAS experiment during Runs 1 and 2 at the LHC. The studies presented focus on data taken during 2012 at ...a centre-of-mass energy of s=8TeV, and during 2015-2016 at s=13TeV. Some predictions toward future runs are also presented. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed.
Abstract
It is widely accepted that the next lepton collider beyond a
Higgs factory would require center-of-mass energy of the order of up
to 15 TeV. Since, given reasonable space and cost ...restrictions,
conventional accelerator technology reaches its limits near this
energy, high-gradient advanced acceleration concepts are
attractive. Advanced and novel accelerators (ANAs) are leading
candidates due to their ability to produce acceleration gradients on
the order of 1–100 GV/m, leading to compact acceleration
facilities. However, intermediate energy facilities (IEF) are
required to test the critical technology elements on the way towards
multi-TeV-class collliders. Here a science case for a 20–100 GeV
center-of-mass energy ANA-based lepton collider that can be a
candidate for an intermediate energy facility is presented. The IEF
can provide numerous opportunities for high energy physics studies
including precision Quantum Chromodynamics and Beyond the Standard
Model physics measurements, investigation of charged particle
interactions with extreme electromagnetic fields, and exploring muon
and proton beam acceleration. Possible applications of this collider
include the studies of γγ and electron beam-fixed
target/beamdump collider designs. Thus, the goal of the proposed IEF
is to both carry out particle physics measurements in the
20-100 GeV ranges as well as to serve as an ANA demonstrator
facility.
The reconstruction of vertices corresponding to proton-proton collisions in ATLAS is an essential element of event reconstruction used in many performance studies and physics analyses. During Run-1 ...of the LHC, ATLAS has employed an iterative approach to vertex finding. In order to improve the flexibility of the algorithm and ensure continued performance for very high numbers of simultaneous collisions in Run-2 of the LHC and beyond, a new approach to seeding vertex finding has been developed inspired by image reconstruction techniques. This note provides a brief outline of how reconstructed tracks are used to create an image of likely vertex collisions in an event, describes the implementation in the ATLAS software, and presents some preliminary results of the performance of the algorithm in simulation approximating early Run-2 conditions.
Large international collaborations that use decentralized computing models are becoming a custom rather than an exception in High Energy Physics. A good computing model for such big collaborations ...has to deal with the distribution of the experiment-specific software around the world. When the CDF experiment developed its software infrastructure, most computing was done on dedicated clusters. As a result, libraries, configuration files and large executables were deployed over a shared file system. In order to adapt its computing model to the Grid, CDF decided to distribute its software to all European Grid sites using Parrot, a user-level application capable of attaching existing programs to remote I/O systems through the filesystem interface. This choice allows CDF to use just one centralized source of code and a scalable set of caches all around Europe to efficiently distribute its code and requires almost no interaction with the existing Grid middleware or with local system administrators. This system has been in production at CDF in Europe since almost two years. Here, we present CDF implementation of Parrot and some comments on its performances.
Presented in this contribution are methods currently developed and used by the ATLAS collaboration to measure the performance of the primary vertex reconstruction algorithms. With the increasing ...instantaneous luminosity at the LHC, many proton-proton collisions occur simultaneously in one bunch crossing. The correct identification of the primary vertex from a hard scattering process and the knowledge of the number of additional pile-up interactions is crucial for many physics analyses. Under high pile-up conditions, additional effects like splitting one vertex into many or reconstructing several interactions as one also become sizable effects. The mathematical methods, their software implementation, and studies presented in this contribution are methods currently developed and used by the ATLAS collaboration to measure the performance of the primary vertex reconstruction algorithms. Statistical methods based on data and Monte Carlo simulation are both used to disentangle and understand the different contributions.
Muon Collider Forum report Black, K.M.; Li, D.; Stratakis, D. ...
Journal of instrumentation,
02/2024, Letnik:
19, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract A multi-TeV muon collider offers a spectacular opportunity in the direct exploration of the energy frontier. Offering a combination of unprecedented energy collisions in a comparatively ...clean leptonic environment, a high energy muon collider has the unique potential to provide both precision measurements and the highest energy reach in one machine that cannot be paralleled by any currently available technology. The topic generated a lot of excitement in Snowmass meetings and continues to attract a large number of supporters, including many from the early career community. In light of this very strong interest within the US particle physics community, Snowmass Energy, Theory and Accelerator Frontiers created a cross-frontier Muon Collider Forum in November of 2020. The Forum has been meeting on a monthly basis and organized several topical workshops dedicated to physics, accelerator technology, and detector R&D. Findings of the Forum are summarized in this report.
Triggering on B-Jets at CDF II Amerio, S.; Casarsa, M.; Cortiana, G. ...
IEEE transactions on nuclear science,
06/2009, Letnik:
56, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In this paper we present a trigger algorithm able to select online events enriched of b-jets. This feature is of central interest in order to extend the physics reach for standard model and minimal ...super symmetric model Higgs decaying into a pair of b -quarks. The algorithm fully exploits the recently upgraded CDFII tracking system and Level 2 CALorimeter cluster finder. These upgrades are necessary to cope with Tevatron increasing luminosity and provide new and refined trigger primitives that are the key elements of our algorithm together with the already existing silicon vertex trigger. A b -hadron can travel some millimeters before decaying and the trigger algorithm exploits this characteristic by searching for tracks displaced with respect to the primary vertex and matched to energetic jets of particles. We discuss the study and the optimization of the algorithm, its technical implementation as well as its performance. The new trigger provides an efficient selection for Higgs decaying into a pair of b -quarks and runs up to high luminosity with an acceptable occupancy of the available bandwidth.
It is widely accepted that the next lepton collider beyond a Higgs factory would require center-of-mass energy of the order of up to 15 TeV. Since, given reasonable space and cost restrictions, ...conventional accelerator technology reaches its limits near this energy, high-gradient advanced acceleration concepts are attractive. Advanced and novel accelerators (ANAs) are leading candidates due to their ability to produce acceleration gradients on the order of 1--100~GV/m, leading to compact acceleration structures. Over the last 10-15 years significant progress has been achieved in accelerating electron beams by ANAs. For example, the demonstration of several-GeV electron beams from laser-powered capillary discharge waveguides, as well as the proof-of-principle coupling of two accelerating structures powered by different laser pulses, has increased interest in ANAs as a viable technology to be considered for a compact, TeV-class, lepton linear collider. However, intermediate facilities are required to test the technology and demonstrate key subsystems. A 20-100 GeV center-of-mass energy ANA-based lepton collider can be a possible candidate for an intermediate facility. Apart from being a test beam facility for accelerator and detector studies, this collider will provide opportunities to study muon and proton beam acceleration, investigate charged particle interactions with extreme electromagnetic fields (relevant for beam delivery system designs and to study the physics at the interaction point), as well as precision Quantum Chromodynamics and Beyond the Standard Model physics measurements. Possible applications of this collider include the studies of \(\gamma\gamma\) and \(e\)-ion collider designs.
Muon colliders provide a unique route to deliver high energy collisions that enable discovery searches and precision measurements to extend our understanding of the fundamental laws of physics. The ...muon collider design aims to deliver physics reach at the highest energies with costs, power consumption and on a time scale that may prove favorable relative to other proposed facilities. In this context, a new international collaboration has formed to further extend the design concepts and performance studies of such a machine. This effort is focused on delivering the elements of a \(\sim\)10 TeV center of mass (CM) energy design to explore the physics energy frontier. The path to such a machine may pass through lower energy options. Currently a 3 TeV CM stage is considered. Other energy stages could also be explored, e.g. an s-channel Higgs Factory operating at 125 GeV CM. We describe the status of the R&D and design effort towards such a machine and lay out a plan to bring these concepts to maturity as a tool for the high energy physics community.
In this paper, we describe the development and the performance studies of a trigger devoted to the identification of b-jets final state events in pp interactions at the CDF II experiment of Tevatron ...collider at Fermilab. Exploiting new trigger primitives provided by two recent trigger upgrades, the Level2 XFT stereo tracking and the improved Level2 cluster- finder, in conjunction with the existing silicon vertex tracker (SVT), we design an online trigger algorithm aimed at selecting good purity 6-jets samples useful for many physics measurements, one of the most important being inclusive searches for the Standard Model Higgs boson. We describe the performances of the proposed algorithm, which must guarantee high efficiency on signal events while maintaining sustainable rate at the luminosity of 3ldr10 32 cm -2 s -1 reachable at the Tevatron.
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