2,153 research outputs found
Searches for New Physics at the Tevatron and LHC
This is an auspicious moment in experimental particle physics -there are
large data samples at the Tevatron and a new energy regime being explored at
the Large Hadron Collider with ever larger data samples. The coincidence of
these two events suggests that we will soon be able to address the question,
what lies beyond the standard model? Particle physics's current understanding
of the universe is embodied in it. The model has been tested to extreme
precision - better than a part in ten thousand - but we suspect that it is only
an approximation, and that physics beyond this standard model will appear in
the data of the Tevatron and LHC in the near future. This brief review touches
on the status of searches for new physics at the time of the conference.Comment: Eight pages, eight figures, Proceedings for the 19th Particles &
Nuclei International Conference (PANIC 2011). Small text edit
Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC
This document describes the work achieved under the OJI award received May 2008 by Peter Wittich as Principal Investigator. The proposal covers experimental particle physics project searching for physics beyond the standard model at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research
Giant Spin-splitting in the Bi/Ag(111) Surface Alloy
Surface alloying is shown to produce electronic states with a very large
spin-splitting. We discuss the long range ordered bismuth/silver(111) surface
alloy where an energy bands separation of up to one eV is achieved. Such strong
spin-splitting enables angular resolved photoemission spectroscopy to directly
observe the region close to the band edge, where the density of states shows
quasi-one dimensional behavior. The associated singularity in the local density
of states has been measured by low temperature scanning tunneling spectroscopy.
The implications of this new class of materials for potential spintronics
applications as well as fundamental issues are discussed.Comment: 4 pages, 4 figure
Parallelized and Vectorized Tracking Using Kalman Filters with CMS Detector Geometry and Events
The High-Luminosity Large Hadron Collider at CERN will be characterized by
greater pileup of events and higher occupancy, making the track reconstruction
even more computationally demanding. Existing algorithms at the LHC are based
on Kalman filter techniques with proven excellent physics performance under a
variety of conditions. Starting in 2014, we have been developing
Kalman-filter-based methods for track finding and fitting adapted for many-core
SIMD processors that are becoming dominant in high-performance systems.
This paper summarizes the latest extensions to our software that allow it to
run on the realistic CMS-2017 tracker geometry using CMSSW-generated events,
including pileup. The reconstructed tracks can be validated against either the
CMSSW simulation that generated the hits, or the CMSSW reconstruction of the
tracks. In general, the code's computational performance has continued to
improve while the above capabilities were being added. We demonstrate that the
present Kalman filter implementation is able to reconstruct events with
comparable physics performance to CMSSW, while providing generally better
computational performance. Further plans for advancing the software are
discussed
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Searches for New Physics at the Tevatron and LHC
This is an auspicious moment in experimental particle physics - there are large data samples at the Tevatron and a new energy regime being explored at the Large Hadron Collider with ever larger data samples. The coincidence of these two events suggests that we will soon be able to address the question, what lies beyond the standard model? Particle physics's current understanding of the universe is embodied in it. The model has been tested to extreme precision - better than a part in ten thousand - but we suspect that it is only an approximation, and that physics beyond this standard model will appear in the data of the Tevatron and LHC in the near future. This brief review touches on the status of searches for new physics at the time of the conference
FPGA-Based Tracklet Approach to Level-1 Track Finding at CMS for the HL-LHC
During the High Luminosity LHC, the CMS detector will need charged particle
tracking at the hardware trigger level to maintain a manageable trigger rate
and achieve its physics goals. The tracklet approach is a track-finding
algorithm based on a road-search algorithm that has been implemented on
commercially available FPGA technology. The tracklet algorithm has achieved
high performance in track-finding and completes tracking within 3.4 s on a
Xilinx Virtex-7 FPGA. An overview of the algorithm and its implementation on an
FPGA is given, results are shown from a demonstrator test stand and system
performance studies are presented.Comment: Submitted to proceedings of Connecting The Dots/Intelligent Trackers
2017, Orsay, Franc
Reconstruction of Charged Particle Tracks in Realistic Detector Geometry Using a Vectorized and Parallelized Kalman Filter Algorithm
One of the most computationally challenging problems expected for the
High-Luminosity Large Hadron Collider (HL-LHC) is finding and fitting particle
tracks during event reconstruction. Algorithms used at the LHC today rely on
Kalman filtering, which builds physical trajectories incrementally while
incorporating material effects and error estimation. Recognizing the need for
faster computational throughput, we have adapted Kalman-filter-based methods
for highly parallel, many-core SIMD and SIMT architectures that are now
prevalent in high-performance hardware. Previously we observed significant
parallel speedups, with physics performance comparable to CMS standard
tracking, on Intel Xeon, Intel Xeon Phi, and (to a limited extent) NVIDIA GPUs.
While early tests were based on artificial events occurring inside an idealized
barrel detector, we showed subsequently that our mkFit software builds tracks
successfully from complex simulated events (including detector pileup)
occurring inside a geometrically accurate representation of the CMS-2017
tracker. Here, we report on advances in both the computational and physics
performance of mkFit, as well as progress toward integration with CMS
production software. Recently we have improved the overall efficiency of the
algorithm by preserving short track candidates at a relatively early stage
rather than attempting to extend them over many layers. Moreover, mkFit
formerly produced an excess of duplicate tracks; these are now explicitly
removed in an additional processing step. We demonstrate that with these
enhancements, mkFit becomes a suitable choice for the first iteration of CMS
tracking, and eventually for later iterations as well. We plan to test this
capability in the CMS High Level Trigger during Run 3 of the LHC, with an
ultimate goal of using it in both the CMS HLT and offline reconstruction for
the HL-LHC CMS tracker
Learning from errors:Assessing final year medical students' reflection on safety improvement, five year cohort study
Abstract Background Investigation of real incidents has been consistently identified by expert reviews and student surveys as a potentially valuable teaching resource for medical students. The aim of this study was to adapt a published method to measure resident doctors’ reflection on quality improvement and evaluate this as an assessment tool for medical students. Methods The design is a cohort study. Medical students were prepared with a tutorial in team based learning format and an online Managing Incident Review course. The reliability of the modified Mayo Evaluation of Reflection on Improvement tool (mMERIT) was analysed with Generalizability G-theory. Long term sustainability of assessment of incident review with mMERIT was tested over five consecutive years. Results A total of 824 students have completed an incident review using 167 incidents from NHS Tayside’s online reporting system. In order to address the academic practice gap students were supervised by Senior Charge Nurses or Consultants on the wards where the incidents had been reported. Inter-rater reliability was considered sufficiently high to have one assessor for each student report. There was no evidence of a gradient in student marks across the academic year. Marks were significantly higher for students who used Section Questions to structure their reports compared with those who did not. In Year 1 of the study 21 (14%) of 153 mMERIT reports were graded as concern. All 21 of these students achieved the required standard on resubmission. Rates of resubmission were lower (3% to 7%) in subsequent years. Conclusions We have shown that mMERIT has high reliability with one rater. mMERIT can be used by students as part of a suite of feedback to help supplement their self-assessment on their learning needs and develop insightful practice to drive their development of quality, safety and person centred professional practice. Incident review addresses the need for workplace based learning and use of real life examples of mistakes, which has been identified by previous studies of education about patient safety in medical schools
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