M. Musich

The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at the CMS experiment. Based on these results, the collaboration has chosen to use n-in-p type silicon sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated this decision.

The high luminosity upgrade of the Large Hadron Collider, foreseen for 2026, necessitates the replacement of the CMS experiment’s silicon tracker. The innermost layer of the new pixel detector will be exposed to severe radiation, corresponding to a 1 MeV neutron equivalent fluence of up to $$\Phi _{eq} = 2 \times 10^{16}$$ cm $$^{-2}$$ , and an ionising dose of $${\approx } 5$$ MGy after an integrated luminosity of 3000 fb $$^{-1}$$ . Thin, planar silicon sensors are good candidates for this application, since the degradation of the signal produced by traversing particles is less severe than for thicker devices. In this paper, the results obtained from the characterisation of 100 and 200 $$\upmu $$ m thick p-bulk pad diodes and strip sensors irradiated up to fluences of $$\Phi _{eq} = 1.3 \times 10^{16}$$ cm $$^{-2}$$ are shown.

A new CMS Tracker is under development for operation at the High Luminosity LHC from 2026 onwards. It includes an outer tracker based on dedicated modules that will reconstruct short track segments, called stubs, using spatially coincident clusters in two closely spaced silicon sensor layers. These modules allow the rejection of low transverse momentum track hits and reduce the data volume before transmission to the first level trigger. The inclusion of tracking information in the trigger decision is essential to limit the first level trigger accept rate. A customized front-end readout chip, the CMS Binary Chip (CBC), containing stub finding logic has been designed for this purpose. A prototype module, equipped with the CBC chip, has been constructed and operated for the first time in a 4 GeV/c positron beam at DESY. The behaviour of the stub finding was studied for different angles of beam incidence on a module, which allows an estimate of the sensitivity to transverse momentum within the future CMS detector. A sharp transverse momentum threshold around 2 GeV/c was demonstrated, which meets the requirement to reject a large fraction of low momentum tracks present in the LHC environment on-detector. This is the first realistic demonstration of a silicon tracking module that is able to select data, based on the particle's transverse momentum, for use in a first level trigger at the LHC . The results from this test are described here.

The Compact Muon Solenoid (CMS) experiment makes a vast use of alignment and calibration measurements in several data processing workflows: in the High Level Trigger, in the processing of the recorded collisions and in the production of simulated events for data analysis and studies of detector upgrades. A complete alignment and calibration scenario is factored in approximately three-hundred records, which are updated independently and can have a time-dependent content, to reflect the evolution of the detector and data taking conditions. Given the complexity of the CMS condition scenarios and the large number (50) of experts who actively measure and release calibration data, in 2015 a novel web-based service has been developed to structure and streamline their management. The cmsDbBrowser provides an intuitive and easily accessible entry point for the navigation of existing conditions by any CMS member, for the bookkeeping of record updates and for the actual composition of complete calibration scenarios. This paper describes the design, choice of technologies and the first year of usage in production of the cmsDbBrowser.

Observation of the electroweak gauge bosons via their decays to electrons and muons provide an important test of the Standard Model of particle physics.Inclusive W and Z boson cross section measurements provide checks of Next-to-Next-to-Leading-Order perturbative QCD calculations, while differential and double-differential Drell-Yan cross section investigate both QCD and PDF constraints.The measurement of the associated production of jets and vector bosons allows for stringent constraints of perturbative QCD calculations and is sensitive to the presence of new physics beyond the Standard Model.Measurements of jet production rates in association with W , Z/γ * , in proton-proton collisions at 7 and 8 TeV center-of-mass energy are presented, using data collected with the ATLAS and CMS detector.Measurements include inclusive jet multiplicity, differential jet cross sections, as well as associated charm-and bottom-quark jet production.

The exploitation of the full physics potential of the LHC experiments requires fast and efficient processing of the largest possible dataset with the most refined understanding of the detector conditions. To face this challenge, the CMS collaboration has setup an infrastructure for the continuous unattended computation of the alignment and calibration constants, allowing for a refined knowledge of the most time-critical parameters already a few hours after the data have been saved to disk. This is the prompt calibration framework which, since the beginning of the LHC Run-I, enables the analysis and the High Level Trigger of the experiment to consume the most up-to-date conditions optimizing the performance of the physics objects. In the Run-II this setup has been further expanded to include even more complex calibration algorithms requiring higher statistics to reach the needed precision. This imposed the introduction of a new paradigm in the creation of the calibration datasets for unattended workflows and opened the door to a further step in performance. The paper reviews the design of these automated calibration workflows, the operational experience in the Run-II and the monitoring infrastructure developed to ensure the reliability of the service.

The CMS detector at the Large Hadron Collider (LHC) is a very complex apparatus with more than 70 million acquisition channels.To exploit its full physics potential, a very careful calibration of the various components, together with an optimal knowledge of their position in space, is essential.The CMS Collaboration has set up a powerful infrastructure to allow for the best knowledge of these conditions at any given moment.The quick turnaround of these workflows was proven crucial both for the algorithms performing the online event selection and for the ultimate resolution of the offline reconstruction of the physics objects.The contribution will report about the design and performance of these workflows during the operations of the 13TeV LHC RunII.

A review was conducted of three systems analysis (SA) studies performed by Lockheed Idaho Technologies Company (LITCO) on integrated thermal treatment systems (ITTSs) and integrated nonthermal treatment systems (INTSs) for the remediation of mixed low-level waste (MLLW) stored throughout the U.S. Department of Energy (DOE) weapons complex. The review was performed by an independent team led by the Energy & Environmental Research Center (EERC), including Science Applications International Corporation, the Waste Policy Institute (WPI), and Virginia Tech. The three studies reviewed were as follows: (1) Integrated Thermal Treatment System Study, Phase 1 - issued July 1994, (2) Integrated Thermal Treatment System Study, Phase 2 - issued February 1996, and (3) Integrated Nonthermal Treatment System Study - drafted March 1996. The three studies were commissioned by DOE to be SA studies of environmental management (EM) systems. The purpose of LITCO`s engineering evaluation of the MLLW treatment system alternatives was to help DOE in the prioritization of research, development, and demonstration activities for remediation technologies. The review of these three studies was structured to further aid DOE in its current and future decision-making processes. The methodology in the studies was compared to a sound systems engineering (SE) approach to help DOE determine which tasks still need to be accomplished to complete a thorough design/review.

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