Journal articles: 'High luminosty LHC'

1

Tomás, R., G. Arduini, P. Baudrenghien, O. Brüning, R. Bruce, X. Buffat, R. Calaga, et al. "Operational scenario of first high luminosity LHC run." Journal of Physics: Conference Series 2420, no. 1 (January 1, 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2420/1/012003.

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Abstract A new scenario for the first operational run of the High Luminoisty LHC (HL–LHC) era (Run 4) has recently been developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL–LHC design target. The operational scenario in terms of beam parameters and machine settings, as well as the different phases to reach optimal performance, are described here along with the impact of potential delays to key hardware components.

2

Wotton, S. A. "The LHCb RICH upgrade for the high luminosity LHC era." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 1058 (January 2024): 168824. http://dx.doi.org/10.1016/j.nima.2023.168824.

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Capriotti, Lorenzo. "Spectroscopy at LHCb: experimental overview." Journal of Physics: Conference Series 2586, no. 1 (September 1, 2023): 012002. http://dx.doi.org/10.1088/1742-6596/2586/1/012002.

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Abstract The large dataset collected in proton-proton collisions at the LHC allows precision studies and discovery of new states in the field of conventional and exotic heavy-hadron spectroscopy; both are crucial to understand QCD dynamics and binding rules. This is possible due to high luminosity, high b/c-hadron production cross-section and the unique, dedicated design of the LHCb detector, optimised to reconstruct b/c-hadron decays. The latest results on conventional and exotic spectroscopy from LHCb are presented.

4

de Melo, Tessio B., Farinaldo S. Queiroz, and Yoxara Villamizar. "Doubly charged scalar at the High-Luminosity and High-Energy LHC." International Journal of Modern Physics A 34, no. 27 (September 27, 2019): 1950157. http://dx.doi.org/10.1142/s0217751x19501574.

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Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly charged scalars assuming that they decay promptly and exclusively into charged leptons. Our study focuses on the fit to the same-sign dilepton mass spectra and it is based on proton–proton collisions at 13 TeV, 14 TeV and 27 TeV with integrated luminosity of [Formula: see text] fb[Formula: see text], 3 ab[Formula: see text] and 15 ab[Formula: see text]. We find that HL-LHC may probe doubly charged scalars masses up to 2.3 TeV, whereas HE-LHC can impressively probe masses up to 3 TeV, conclusively constituting a complementary and important probe to signs of doubly charged scalars in lepton flavor violation decays and lepton–lepton colliders.

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Kiehn, Moritz, Sabrina Amrouche, Paolo Calafiura, Victor Estrade, Steven Farrell, Cécile Germain, Vava Gligorov, et al. "The TrackML high-energy physics tracking challenge on Kaggle." EPJ Web of Conferences 214 (2019): 06037. http://dx.doi.org/10.1051/epjconf/201921406037.

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The High-Luminosity LHC (HL-LHC) is expected to reach unprecedented collision intensities, which in turn will greatly increase the complexity of tracking within the event reconstruction. To reach out to computer science specialists, a tracking machine learning challenge (TrackML) was set up on Kaggle by a team of ATLAS, CMS, and LHCb physicists tracking experts and computer scientists building on the experience of the successful Higgs Machine Learning challenge in 2014. A training dataset based on a simulation of a generic HL-LHC experiment tracker has been created, listing for each event the measured 3D points, and the list of 3D points associated to a true track.The participants to the challenge should find the tracks in the test dataset, which means building the list of 3D points belonging to each track.The emphasis is to expose innovative approaches, rather than hyper-optimising known approaches. A metric reflecting the accuracy of a model at finding the proper associations that matter most to physics analysis will allow to select good candidates to augment or replace existing algorithms.

6

Giacobbe, B. "LUCID-3: the upgrade of the ATLAS luminosity detector for High-Luminosity LHC." Journal of Instrumentation 19, no. 03 (March 1, 2024): C03053. http://dx.doi.org/10.1088/1748-0221/19/03/c03053.

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Abstract The ATLAS physics program at the High Luminosity LHC (HL-LHC) calls for a precision in the luminosity measurement of 1%. A larger uncertainty would represent the dominant systematic error in precision measurements, including those in the Higgs sector. To fulfill such requirement in an environment characterized by up to 140 simultaneous interactions per crossing (200 in the ultimate scenario), ATLAS will feature several luminosity detectors. At least some of them must be both calibratable in the van der Meer scans at low luminosity and able to measure up to the highest values. LUCID-3, the upgrade of the present ATLAS luminometer (LUCID-2), will fulfill such a condition. The reasons for an upgrade of LUCID-2 and the envisaged solutions are discussed and a description of the LUCID-3 project is given. Finally, the first results obtained with the prototypes installed in ATLAS during the present LHC Run-3 are discussed as means of the validation of the final design.

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NAKAMOTO, Tatsushi. "The High Luminosity LHC Upgrade Project." TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 52, no. 3 (2017): 141–48. http://dx.doi.org/10.2221/jcsj.52.141.

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Arduini, G., J. Barranco, A. Bertarelli, N. Biancacci, R. Bruce, O. Brüning, X. Buffat, et al. "High Luminosity LHC: challenges and plans." Journal of Instrumentation 11, no. 12 (December 28, 2016): C12081. http://dx.doi.org/10.1088/1748-0221/11/12/c12081.

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Jezequel, S. "Prospects for the high-luminosity LHC." Nuclear Physics B - Proceedings Supplements 245 (December 2013): 145–48. http://dx.doi.org/10.1016/j.nuclphysbps.2013.10.027.

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Tricomi, Alessia. "SLHC: The LHC luminosity upgrade." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 596, no. 1 (October 2008): 43–47. http://dx.doi.org/10.1016/j.nima.2008.07.118.

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11

Venditti, Rosamaria. "Prospects for Higgs Boson Measurements and Beyond Standard Model Physics at the High-Luminosity LHC with CMS." EPJ Web of Conferences 192 (2018): 00032. http://dx.doi.org/10.1051/epjconf/201819200032.

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The High-Luminosity Large Hadron Collider (HL-LHC) is a major upgrade of the LHC, expected to deliver an integrated luminosity of up to 3000/fb over one decade. The very high instantaneous luminosity will lead to about 200 proton-proton collisions per bunch crossing (pileup) superimposed to each event of interest, therefore providing extremely challenging experimental conditions. The scientific goals of the HL-LHC physics program include precise measurement of the properties of the recently discovered standard model Higgs boson and searches for beyond the standard model physics (heavy vector bosons, SUSY, dark matter and exotic long-lived signatures, to name a few). In this contribution we will present the strategy of the CMS experiment to investigate the feasibility of such search and quantify the increase of sensitivity in the HL-LHC scenario.

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Mounet, N., R. Tomás, D. Amorim, C. Antuono, N. Biancacci, H. Bartosik, P. Baudrenghien, et al. "High intensity beam dynamics assessment and challenges for HL-LHC." Journal of Instrumentation 19, no. 05 (May 1, 2024): T05016. http://dx.doi.org/10.1088/1748-0221/19/05/t05016.

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Abstract The High Luminosity (HL-LHC) project aims to increase the integrated luminosity of CERN's Large Hadron Collider (LHC) by an order of magnitude compared to its initial design. This requires a large increase in bunch intensity and beam brightness compared to the first three LHC runs, and hence poses serious collective-effects challenges, related in particular to electron cloud, instabilities from beam-coupling impedance, and beam-beam effects. Here, we present the associated constraints and the mitigation measures proposed to achieve the baseline performance of the upgraded LHC machine. We also discuss the interplay of these mitigation measures with other aspects of the accelerator, such as optics, physical and dynamic apertures, the collimation system, and crab cavities. Additional potential sources of intensity limitations are also briefly discussed.

13

Maria, R. De, R. Bruce, D. Gamba, M. Giovannozzi, and F. Plassard. "High Luminosity LHC Optics and Layout HLLHCV1.4." Journal of Physics: Conference Series 1350 (November 2019): 012001. http://dx.doi.org/10.1088/1742-6596/1350/1/012001.

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14

Longo, Riccardo. "Joint ATLAS/CMS ZDC upgrade project for the High Luminosity LHC." EPJ Web of Conferences 276 (2023): 05003. http://dx.doi.org/10.1051/epjconf/202327605003.

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The High Luminosity LHC (HL-LHC) provides the opportunity to study heavy ion, proton-nucleus, photon-nucleus and photon-photon collisions with unprecedented luminosities at the TeV scale. The LHC heavy ion community has mapped out an extensive range of physics measurements at the HLLHC that will push forward our understanding of both QCD, QED and even electroweak physics. The measurement of forward neutrons and photons in Zero Degree Calorimeters (ZDCs) is essential for event classification and triggering. In order to reach the required luminosities, the LHC interaction regions will be redesigned, necessitating the need to build new ZDCs that will be both narrower and much more radiation tolerant. This challenge motivated the formation of a joint project between ATLAS and CMS to build new ZDCs for Run 4, JZCaP. The ZDCs are based on radiation-hard fused silica rods that produce Cherenkov light. These rods have been developed by Heraeus Quartzglas in collaboration with JZCaP and the LHC BRAN and FLUKA groups. The Run 4 ZDCs (HL-ZDCs) are the first joint detector project between CMS and ATLAS. This talk will present the capabilities of the new ZDCs and recent R&D highlights.

15

Haranko, Mykyta. "Luminosity and beam-induced background measurement with the CMS Tracker Endcap Pixel Detector at HL-LHC." Journal of Physics: Conference Series 2374, no. 1 (November 1, 2022): 012008. http://dx.doi.org/10.1088/1742-6596/2374/1/012008.

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The High-Luminosity upgrade of the LHC (HL-LHC) places unprecedented requirements for background monitoring and luminosity measurements. The CMS Tracker Endcap Pixel Detector (TEPX) will be adapted to provide high-precision online measurements of bunch-by-bunch luminosity and beam-induced background. The implementation of dedicated triggering and readout systems, the real-time clustering algorithm on an FPGA and the expected performance are discussed.

16

Aly, R. "Longevity study on the CMS resistive plate chambers for HL-LHC." Journal of Instrumentation 17, no. 08 (August 1, 2022): C08008. http://dx.doi.org/10.1088/1748-0221/17/08/c08008.

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Abstract The CMS Resistive Plate Chamber (RPC) system has been certified for 10 years of LHC operation. In the next years, during the High luminosity LHC (HL-LHC) phase, the LHC instantaneous luminosity will increase to a factor five more than the existing LHC luminosity. This will subject the present CMS RPC system to background rates and operating conditions much higher with respect to those for which the detectors have been designed. Those conditions could affect the detector properties and introduce nonrecoverable aging effects. A dedicated longevity test is set up in the CERN Gamma Irradiation Facility (GIF++) to determine if the present RPC detectors can survive the hard background conditions during the HL-LHC running period. During the irradiation test, the RPC detectors are exposed to a high gamma radiation for a long period and the detector main parameters are monitored as a function of the integrated charge. Based on collecting a large fraction of the expected integrated charge at the LH-LHC. The results of the irradiation test will be presented.

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Sundararajan, P., and K. Ntekas. "New developments in the MDT trigger processor for the ATLAS Level-0 muon trigger at High Luminosity LHC." Journal of Instrumentation 18, no. 02 (February 1, 2023): C02030. http://dx.doi.org/10.1088/1748-0221/18/02/c02030.

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Abstract The High Luminosity LHC (HL-LHC) will have an instantaneous luminosity 5–7 times higher than LHC. The ATLAS detector, trigger and data acquisition systems will undergo a significant upgrade to cope with the increased particle rate. The upgrade of the ATLAS first-level muon trigger for High-Luminosity LHC foresees incorporating the high-resolution tracking capability of the Monitored Drift Tubes (MDT) in the current system based on Resistive Plate Chambers and Thin Gap Chambers. The MDT Trigger Processor (MDTTP) processes muon trigger candidates along with MDT hits to improve the accuracy of the transverse momentum calculation at the first-level (level-0) of the muon trigger. One of the major challenges is the capability to process all candidates in a bunch crossing within a tight latency constraint. The MDTTP hardware is based on the Apollo ATCA platform [6]. A complete hardware demonstrator is available and an updated prototype has been recently developed. Recent updates in the firmware development, integration and testing are presented.

18

Adorisio, C., and S. Roesler. "Induced activation studies for the LHC upgrade to High Luminosity LHC." Journal of Physics: Conference Series 1046 (June 2018): 012008. http://dx.doi.org/10.1088/1742-6596/1046/1/012008.

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Mastrolorenzo, L. "The CMS High Granularity Calorimeter for HL-LHC." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860075. http://dx.doi.org/10.1142/s2010194518600753.

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The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS Collaboration is designing a High Granularity Calorimeter (HGCAL) to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (CE-E) and hadronic (CE-H) compartments. This will facilitate particle-flow (PF) calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The CE-E and a large fraction of CE-H will be based on hexagonal silicon sensors of [Formula: see text] cell size, with the remainder of the CE-H based on highly-segmented scintillators with SiPM readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection. An overview of the HGCAL project is presented in this paper.

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Yohay, R. "The CMS High Granularity Calorimeter for High Luminosity LHC." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 958 (April 2020): 162151. http://dx.doi.org/10.1016/j.nima.2019.04.105.

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Brüning, Oliver, Heather Gray, Katja Klein, Mike Lamont, Meenakshi Narain, Richard Polifka, and Lucio Rossi. "The scientific potential and technological challenges of the High-Luminosity Large Hadron Collider program." Reports on Progress in Physics 85, no. 4 (March 29, 2022): 046201. http://dx.doi.org/10.1088/1361-6633/ac5106.

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Abstract We present an overview of the High-Luminosity (HL-LHC) program at the Large Hadron Collider (LHC), its scientific potential and technological challenges for both the accelerator and detectors. The HL-LHC program is expected to start circa 2027 and aims to increase the integrated luminosity delivered by the LHC by an order of magnitude at the collision energy of 14 TeV. This requires upgrades to the injector system, accelerator complex and luminosity levelling. The two experiments, ATLAS and CMS, require substantial upgrades to most of their systems in order to cope with the increased interaction rate, and much higher radiation levels than at the current LHC. We present selected examples based on novel ideas and technologies for applications at a hadron collider. Both experiments will replace their tracking systems. We describe the ATLAS pixel detector upgrade featuring novel tilted modules, and the CMS Outer Tracker upgrade with a new module design enabling use of tracks in the level-1 trigger system. CMS will also install state-of-the-art highly segmented calorimeter endcaps. Finally, we describe new picosecond precision timing detectors of both experiments. In addition, we discuss how the upgrades will enhance the physics performance of the experiments, and solve the computing challenges posed by the expected large data sets. The physics program of the HL-LHC is focused on precision measurements probing the limits of the Standard Model (SM) of particle physics and discovering new physics. We present a selection of studies that have been carried out to motivate the HL-LHC program. A central topic of exploration will be the characterization of the Higgs boson. The large HL-LHC data samples will extend the sensitivity of searches for new particles or new interactions whose existence has been hypothesized in order to explain shortcomings of the SM. Finally, we comment on the nature of large scientific collaborations.

22

Missio, Marion. "Overview of the ATLAS High-Granularity Timing Detector: project status and results." Journal of Instrumentation 19, no. 04 (April 1, 2024): C04008. http://dx.doi.org/10.1088/1748-0221/19/04/c04008.

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Abstract The increase of the particle flux (pile-up) at the high-luminosity phase of the Large Hadron Collider (LHC) with an instantaneous luminosity up to L ≈ 7.5 × 1034 cm-2 s-1 will have a severe impact on the ATLAS detector reconstruction and trigger performance. A High Granularity Timing Detector (HGTD) will be installed in the forward region for pile-up mitigation and luminosity measurement. This detector, based on Low Gain Avalanche Detectors and custom ASICs, will provide a time resolution of 30 ps per track at the beginning of HL-LHC and 50 ps at the end. This proceeding paper will summarise the overall specifications of the HGTD as well as the project status.

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Accettura, Carlotta, David Amorim, Alekseyevichx Antipov, Adrienn Baris, Alessandro Bertarelli, Nicolò Biancacci, Sergio Calatroni, et al. "Resistivity Characterization of Molybdenum-Coated Graphite-Based Substrates for High-Luminosity LHC Collimators." Coatings 10, no. 4 (April 7, 2020): 361. http://dx.doi.org/10.3390/coatings10040361.

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The High-Luminosity Large Hadron Collider (HL-LHC) project aims at extending the operability of the LHC by another decade and increasing by more than a factor of ten the integrated luminosity that the LHC will have collected by the end of Run 3. This will require doubling the beam intensity and reducing the transverse beam size compared to those of the LHC design. The higher beam brightness poses new challenges for machine safety, due to the large energy of 700 MJ stored in the beams, and for beam stability, mainly due to the collimator contribution to the total LHC beam coupling impedance. A rich research program was therefore started to identify suitable materials and collimator designs, not only fulfilling impedance reduction requirements but also granting adequate beam-cleaning and robustness against failures. The use of thin molybdenum coatings on a molybdenum–graphite substrate has been identified as the most promising solution to meet both collimation and impedance requirements, and it is now the baseline choice of the HL-LHC project. In this work we present the main results of the coating characterization, in particular addressing the impact of coating microstructure on the electrical resistivity with different techniques, from Direct Current (DC) to GHz frequency range.

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Tortajada, Ignacio Asensi. "Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC." EPJ Web of Conferences 170 (2018): 01001. http://dx.doi.org/10.1051/epjconf/201817001001.

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The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. The Tile Calorimeter (TileCal) will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and then transferred directly to the off-detector electronics, where the signals will be reconstructed, stored, and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the reliability and redundancy of the system. Three different front-end options are presently being investigated for the upgrade, two of them based on ASICs, and a final solution will be chosen after extensive laboratory and test beam studies that are in progress. A hybrid demonstrator module is being developed using the new electronics while conserving compatibility with the current system. The status of the developments will be presented, including results from the several tests with particle beams.

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Feng, Jonathan L., Felix Kling, Mary Hall Reno, Juan Rojo, Dennis Soldin, Luis A. Anchordoqui, Jamie Boyd, et al. "The Forward Physics Facility at the High-Luminosity LHC." Journal of Physics G: Nuclear and Particle Physics 50, no. 3 (January 20, 2023): 030501. http://dx.doi.org/10.1088/1361-6471/ac865e.

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Abstract High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF’s physics potential.

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Matis, H. S., M. Placidi, A. Ratti, W. C. Turner, E. Bravin, and R. Miyamoto. "The BRAN luminosity detectors for the LHC." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 848 (March 2017): 114–26. http://dx.doi.org/10.1016/j.nima.2016.12.019.

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Zareef, F., A. Oblakowska-Mucha, and T. Szumlak. "Silicon detectors beyond LHC — RD50 status report." Journal of Instrumentation 17, no. 11 (November 1, 2022): C11004. http://dx.doi.org/10.1088/1748-0221/17/11/c11004.

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Abstract The last decade showed the leading role of the Large Hadron Collider (LHC) experiments in particle physics. To fully exploit its physics potential, the significant increase of LHC luminosity is planned. At the High luminosity Phase-II Upgrade (HL-LHC), foreseen for 2027, a peak instantaneous luminosity of 5 × 1034 cm−2, with an integrated luminosity of 3000 fb−1 is expected. The experiments will be subjected to radiation levels up to 2 × 1016 neq/cm2 at the innermost layers of the detectors. Since more than a decade the RD50 collaboration has been conducting a significant R&D program across experimental boundaries to create silicon sensors with adequate radiation tolerance for HL-LHC trackers. HV-CMOS sensors, 3D detectors, and low gain avalanche detectors (LGADs) are important areas of detector research and development. We will discuss the current state of research and development in numerous silicon detector domains, with a focus on 3D and LGAD detectors. We will also discuss the alternatives for detector selection experiments outside of the LHC, using the FCC as an example.

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Chang, Philip, Peter Elmer, Yanxi Gu, Vyacheslav Krutelyov, Gavin Niendorf, Michael Reid, Balaji Venkat Sathia Narayanan, et al. "Line Segment Tracking in the High-luminosity LHC." EPJ Web of Conferences 295 (2024): 02019. http://dx.doi.org/10.1051/epjconf/202429502019.

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The Large Hadron Collider (LHC) will be upgraded to Highluminosity LHC, increasing the number of simultaneous proton-proton collisions (pileup, PU) by several-folds. The harsher PU conditions lead to exponentially increasing combinatorics in charged particle tracking, placing a large demand on the computing resources. The projection on required computing resources exceeds the computing budget with the current algorithms running on single-thread CPUs. Motivated by the rise of heterogeneous computing in high-performance computing centers, we present Line Segment Tracking (LST), a highly parallelizeable algorithm that can run efficiently on GPUs and is being integrated to the CMS experiment central software. The usage of Alpaka framework for the algorithm implementation allows better portability of the code to run on different types of commercial parallel processors allowing flexibility on which processors to purchase for the experiment in the future. To verify a similar computational performance with a native solution, the Alpaka implementation is compared with a CUDA one on a NVIDIA Tesla V100 GPU. The algorithm creates short track segments in parallel, and progressively form higher level objects by linking segments that are consistent with genuine physics track hypothesis. The computing and physics performance are on par with the latest, multi-CPU versions of existing CMS tracking algorithms.

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Li, X., G. Liu, J. Chen, B. Deng, D. Gong, D. Guo, M. He, et al. "Optical data transmission ASICs for the high-luminosity LHC (HL-LHC) experiments." Journal of Instrumentation 9, no. 03 (March 6, 2014): C03007. http://dx.doi.org/10.1088/1748-0221/9/03/c03007.

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Sopczak, André. "Luminosity Measurements at the LHC at CERN Using Medipix, Timepix and Timepix3 Devices." Physics 3, no. 3 (August 11, 2021): 579–654. http://dx.doi.org/10.3390/physics3030037.

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The precise determination of the luminosity is essential for many analyses in physics based on the data from the particle accelerator Large Hadron Collider (LHC) at CERN. There are different types of detectors used for the luminosity measurements. The focus of this review is on luminosity measurements with hybrid-pixel detectors and the progress made over the past decade. The first generations of detectors of the Medipix and Timepix families had frame-based readout, while Timepix3 has a quasi-continuous readout. The applications of the detectors are manifold, and in particular, the detectors have been operated in the harsh environment of the LHC. The excellent performance in detecting high fluxes of elementary particles made these detectors ideal tools to measure the delivered luminosity resulting from proton–proton collisions. Important aspects of this review are the performance improvements in relative luminosity measurements from one detector generation to another, the long-term stability of the measurements, absolute luminosity measurements, material activation (radiation-induced) corrections, and the measurement of luminosity from neutron counting. Rather than bunch-average luminosity provided by previous detector generations, owing to the excellent time-resolution, Timepix3 measured the luminosity of individual proton bunches that are 25 ns apart. This review demonstrates the large progress in the precision of luminosity measurements during LHC Run-1 and Run-2 operations using hybrid-pixel detectors, and thus their importance for luminosity measurements in the future of LHC operations.

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Lange, David, Kenneth Bloom, Tommaso Boccali, Oliver Gutsche, and Eric Vaandering. "CMS Computing Resources: Meeting the demands of the high-luminosity LHC physics program." EPJ Web of Conferences 214 (2019): 03055. http://dx.doi.org/10.1051/epjconf/201921403055.

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The high-luminosity program has seen numerous extrapolations of its needed computing resources that each indicate the need for substantial changes if the desired HL-LHC physics program is to be supported within the current level of computing resource budgets. Drivers include large increases in event complexity (leading to increased processing time and analysis data size) and trigger rates needed (5-10 fold increases) for the HL-LHC program. The CMS experiment has recently undertaken an effort to merge the ideas behind short-term and long-term resource models in order to make easier and more reliable extrapolations to future needs. Near term computing resource estimation requirements depend on numerous parameters: LHC uptime and beam intensities; detector and online trigger performance; software performance; analysis data requirements; data access, management, and retention policies; site characteristics; and network performance. Longer term modeling is affected by the same characteristics, but with much larger uncertainties that must be considered to understand the most interesting handles for increasing the "physics per computing dollar" of the HL-LHC. In this presentation, we discuss the current status of long term modeling of the CMS computing resource needs for HL-LHC with emphasis on techniques for extrapolations, uncertainty quantification, and model results. We illustrate potential ways that high-luminosity CMS could accomplish its desired physics program within today's computing budgets.

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Sauvan, J. B. "The CMS High Granularity Calorimeter for the High Luminosity LHC." Journal of Instrumentation 13, no. 02 (February 23, 2018): C02043. http://dx.doi.org/10.1088/1748-0221/13/02/c02043.

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Valentan, Manfred. "The CMS high granularity calorimeter for the high luminosity LHC." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 936 (August 2019): 102–6. http://dx.doi.org/10.1016/j.nima.2018.10.131.

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Alekseev, Aleksandr, Simone Campana, Xavier Espinal, Stephane Jezequel, Andrey Kirianov, Alexei Klimentov, Tatiana Korchuganova, et al. "On the road to a scientific data lake for the High Luminosity LHC era." International Journal of Modern Physics A 35, no. 33 (November 30, 2020): 2030022. http://dx.doi.org/10.1142/s0217751x20300227.

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The experiments at CERN’s Large Hadron Collider use the Worldwide LHC Computing Grid, the WLCG, for its distributed computing infrastructure. Through the distributed workload and data management systems, they provide seamless access to hundreds of grid, HPC and cloud based computing and storage resources that are distributed worldwide to thousands of physicists. LHC experiments annually process more than an exabyte of data using an average of 500,000 distributed CPU cores, to enable hundreds of new scientific results from the collider. However, the resources available to the experiments have been insufficient to meet data processing, simulation and analysis needs over the past five years as the volume of data from the LHC has grown. The problem will be even more severe for the next LHC phases. High Luminosity LHC will be a multiexabyte challenge where the envisaged Storage and Compute needs are a factor 10 to 100 above the expected technology evolution. The particle physics community needs to evolve current computing and data organization models in order to introduce changes in the way it uses and manages the infrastructure, focused on optimizations to bring performance and efficiency not forgetting simplification of operations. In this paper we highlight a recent R&D project related to scientific data lake and federated data storage.

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Baer, Howard, Vernon Barger, Xerxes Tata, and Kairui Zhang. "Detecting Heavy Neutral SUSY Higgs Bosons Decaying to Sparticles at the High-Luminosity LHC." Symmetry 15, no. 2 (February 18, 2023): 548. http://dx.doi.org/10.3390/sym15020548.

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In supersymmetry (SUSY) models with low electroweak naturalness (natSUSY), which have been suggested to be the most likely version of SUSY to emerge from the string landscape, higgsinos are expected at the few hundred GeV scale, whilst electroweak gauginos inhabit the TeV scale. For TeV-scale heavy neutral SUSY Higgs bosons H and A, as currently required by LHC searches, the dominant decay modes of H,A are gaugino plus higgsino provided these decays are kinematically open. The light higgsinos decay to soft particles, so are largely invisible, whilst the gauginos decay to W, Z or h plus missing transverse energy (ET). Thus, we examine the viability of H,A→W+ET, Z+ET and h+ET signatures at the high luminosity LHC (HL-LHC) in light of large standard model (SM) backgrounds from (mainly) tt¯, VV and Vh production (where V=W,Z). We also examine whether these signal channels can be enhanced over backgrounds by requiring the presence of an additional soft lepton from the decays of the light higgsinos. We find significant regions in the vicinity of mA∼1–2 TeV of the mA vs. tanβ plane, which can be probed at the high luminosity LHC, using these dominant signatures by HL-LHC at 5σ and at the 95% confidence level (CL).

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Reis, Thomas. "CMS ECAL upgrade for precision timing and energy measurements at the High Luminosity LHC." Journal of Physics: Conference Series 2374, no. 1 (November 1, 2022): 012072. http://dx.doi.org/10.1088/1742-6596/2374/1/012072.

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The unprecedented instantaneous luminosity provided by the High Luminosity upgrade of the LHC (HL-LHC) at CERN requires an upgrade of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL). The barrel region of the CMS ECAL will be preserved but will be operated at a lower temperature and with a completely new readout and trigger electronics. A dual gain trans-impedance amplifier and an integrated circuit providing two 160 MHz analog to digital converter channels, gain selection, and data compression will be used in the new readout electronics. The trigger decision will be moved off-detector and performed by powerful and flexible field programmable gate array processors, allowing for sophisticated trigger algorithms to be applied. The upgraded ECAL will be capable of high-precision energy measurements throughout HL-LHC data taking and will greatly improve the time resolution for photons and electrons above 10 GeV.

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Mandrik, Petr. "Top FCNC searches at HL-LHC with the CMS experiment." EPJ Web of Conferences 191 (2018): 02009. http://dx.doi.org/10.1051/epjconf/201819102009.

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The Large Hadron Collider is the world’s largest and highest centerof- mass energy particle accelerator. During the Phase I operation it is expected that the LHC operated at a centre-of-mass energy of 13 TeV will deliver to the CMS experiment total integrated luminosity of ~300 fb-1 till 2023. The High Luminosity LHC upgrade is expected to run at a centre-of-mass energy of 14 TeV and will allow ATLAS and CMS to collect integrated luminosities of the order of 300 fb-1 per year, and up to 3000 fb-1 during the HL-LHC projected lifetime of ten years. The large expected integrated luminosity enables the exploration of the multi-TeV scale by searches for particles with high masses as well as by investigation of processes with very low cross sections such as Flavor-Change Neutral Current interactions in top quark sector. In this report we present a proposal for the top quark FCNC searches at HL-LHC based on Monte-Carlo simulation of the upgraded CMS detector.

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Migliore, E. "Status of the upgrade project of the CMS Tracker for HL-LHC." Journal of Instrumentation 17, no. 10 (October 1, 2022): C10003. http://dx.doi.org/10.1088/1748-0221/17/10/c10003.

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Abstract The CMS collaboration is currently preparing the upgrade of the tracking system for the High-Luminosity LHC operations (HL-LHC). The HL-LHC is scheduled to start in 2027 and it will bring the instantaneous luminosity up to 7.5 × 1034 cm−2 s−1, with an average of 200 interactions per beam crossing, and an integrated luminosity up to 4000 fb−1 over a decade. To operate efficiently in these challenging conditions, the new detector has to provide tracking information to the first level trigger stage and maintain good and efficient offline tracking. In this contribution, the layout of the new detector, the main technology choices together with highlights on the current status of the main detector components will be presented.

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Chen, Ziheng, Antonio Di Pilato, Felice Pantaleo, and Marco Rovere. "GPU-based Clustering Algorithm for the CMS High Granularity Calorimeter." EPJ Web of Conferences 245 (2020): 05005. http://dx.doi.org/10.1051/epjconf/202024505005.

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The future High Luminosity LHC (HL-LHC) is expected to deliver about 5 times higher instantaneous luminosity than the present LHC, resulting in pile-up up to 200 interactions per bunch crossing (PU200). As part of the phase-II upgrade program, the CMS collaboration is developing a new endcap calorimeter system, the High Granularity Calorimeter (HGCAL), featuring highly-segmented hexagonal silicon sensors and scintillators with more than 6 million channels. For each event, the HGCAL clustering algorithm needs to group more than 105 hits into clusters. As consequence of both high pile-up and the high granularity, the HGCAL clustering algorithm is confronted with an unprecedented computing load. CLUE (CLUsters of Energy) is a fast fullyparallelizable density-based clustering algorithm, optimized for high pile-up scenarios in high granularity calorimeters. In this paper, we present both CPU and GPU implementations of CLUE in the application of HGCAL clustering in the CMS Software framework (CMSSW). Comparing with the previous HGCAL clustering algorithm, CLUE on CPU (GPU) in CMSSW is 30x (180x) faster in processing PU200 events while outputting almost the same clustering results.

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Baer, Howard, Vernon Barger, Xerxes Tata, and Kairui Zhang. "Prospects for Charged Higgs Bosons in Natural SUSY Models at the High-Luminosity LHC." Symmetry 15, no. 8 (July 25, 2023): 1475. http://dx.doi.org/10.3390/sym15081475.

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We continue our examination of prospects for the discovery of heavy Higgs bosons of natural SUSY (natSUSY) models at the high luminosity LHC (HL-LHC), this time focusing on charged Higgs bosons. In natSUSY, higgsinos are expected at the few hundred GeV scale whilst electroweak gauginos inhabit the TeV scale and the heavy Higgs bosons, H, A and H± could range up tens of TeV without jeopardizing naturalness. For TeV-scale heavy SUSY Higgs bosons H, A and H±, as currently required by LHC searches, SUSY decays into gaugino plus higgsino can dominate H± decays provided these decays are kinematically accessible. The visible decay products of higgsinos are soft making them largely invisible, whilst the gauginos decay to W, Z or h plus missing transverse energy (ET). Charged Higgs bosons are dominantly produced at LHC14 via the parton subprocess, gb→H±t. In this paper, we examine the viability of observing signatures from H±→τν, H±→tb and H±→W,Z,h+ET events produced in association with a top quark at the HL-LHC over large Standard Model (SM) backgrounds from (mainly) tt¯, tt¯V and tt¯h production (where V=W,Z). We find that the greatest reach is found via the SM H±(→τν)+t channel with a subdominant contribution from the H±(→tb)+t channel. Unlike for neutral Higgs searches, the SUSY decay modes appear to be unimportant for H± searches at the HL-LHC. We delineate regions of the mA vs. tanβ plane, mostly around mA∼ 1–2 TeV, where signals from charged Higgs bosons would serve to confirm signals of a heavy, neutral Higgs boson at the 5σ level or, alternatively, to exclude heavy Higgs bosons at the 95% confidence level at the high luminosity LHC.

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Gagnon, L. G. "Machine learning for track reconstruction at the LHC." Journal of Instrumentation 17, no. 02 (February 1, 2022): C02026. http://dx.doi.org/10.1088/1748-0221/17/02/c02026.

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Abstract The planned upgrade of the LHC to its High-Luminosity counterpart (HL-LHC) circa 2027 will bring about a drastic increase in instantaneous luminosity, pileup, and trigger rates. Currently, most LHC experiments use Kalman filter based track reconstruction algorithms which exhibit outstanding physics performance but scale poorly with the amount of data produced per bunch crossing. Therefore, the high energy physics community is currently performing intensive R&D to commission new or improved algorithms for this crucial data reconstruction task. This article presents many approaches such as running existing Kalman filter algorithms on accelerated hardware and overhauling the current approaches with machine learning techniques. A new algorithm testbed for research in track reconstruction, ACTS, is also discussed.

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Simone, F. M., A. Pellecchia, and P. Verwilligen. "Design validation of the CMS Phase-2 Triple-GEM detectors." Journal of Instrumentation 19, no. 03 (March 1, 2024): C03005. http://dx.doi.org/10.1088/1748-0221/19/03/c03005.

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Abstract The High-Luminosity LHC will deliver proton-proton collisions at 5.0–7.5 times the nominal LHC luminosity, with an expected number of 140–200 pp-interactions per bunch crossing. To maintain the performance of muon triggering and reconstruction under high background, the forward part of the Muon spectrometer of the CMS experiment will be upgraded with Gas Electron Multipliers (GEM) and improved Resistive Plate Chambers detectors. Particularly challenging is the extension of the pseudorapidity of the muon system up to |η| < 2.8 with a 6-layer station, named ME0, that will be installed behind the new high granularity calorimeter and that will see particle rates up to 150 kHz/cm2 and integrate a dose of 250 krad by the end of the High Luminosity phase of the LHC. In this contribution we will present the major design changes of the Triple-GEM detectors to adapt them for the harsh radiation environment and the high particle rate. We shall summarize the performance of prototype Triple-GEM detectors measured with X-rays and gamma at the CERN GIF++ irradiation facility.

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Pellecchia, Antonello. "The upgrade of the CMS muon system for the high luminosity LHC." Journal of Instrumentation 19, no. 02 (February 1, 2024): C02077. http://dx.doi.org/10.1088/1748-0221/19/02/c02077.

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Abstract The muon system of the CMS experiment is expected to upgrade all of its subdetectors for the Phase-2 of the Large Hadron Collider (LHC) that will begin in 2029. The upgrade plans for drift tubes (DTs), cathode strip chambers (CSCs) and resistive place chambers (RPCs) include a new electronics for better performance in high background rate conditions and to sustain the large radiation dose delivered by the high-luminosity LHC (HL-LHC). Two new RPC stations will also be installed to complement CSCs in the forward region 1.8 < |η| < 2.4, while three stations of triple-GEM (gas electron multiplier) detectors will complement CSCs in the region 1.5 < |η| < 2.4 and extend the CMS muon system coverage to the very forward pseudorapidity region 2.4 < |η| < 2.8. We present the goals and status of the CMS muon system upgrade including the performance of the early Phase-2 upgrades demonstrated in Run 3 with proton-proton collisions, the performance validation of the new detectors in test beams and the mass production status of the new stations.

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Moscatelli, F., D. Passeri, A. Morozzi, G. F. Dalla Betta, S. Mattiazzo, M. Bomben, and G. M. Bilei. "Surface damage characterization of FBK devices for High Luminosity LHC (HL-LHC) operations." Journal of Instrumentation 12, no. 12 (December 7, 2017): P12010. http://dx.doi.org/10.1088/1748-0221/12/12/p12010.

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Cervelló, A., A. Valero, F. Carrió, J. Torres, J. Soret, and R. García. "A new data transfer scheme for the HL-LHC upgrade of the ATLAS Tile Hadronic Calorimeter." Journal of Physics: Conference Series 2374, no. 1 (November 1, 2022): 012097. http://dx.doi.org/10.1088/1742-6596/2374/1/012097.

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The Large Hadron Collider (LHC) is undergoing a series of upgrades towards a High Luminosity LHC (HL-LHC) that will deliver five times the LHC nominal instantaneous luminosity. The ATLAS experiment is one of the experiments at the LHC that investigates elementary particle interactions in collisions of high-energy proton beams. To prepare for data taking in high-luminosity conditions, the ATLAS Tile Hadronic Calorimeter (TileCal) will replace completely on- and off-detector electronics using a new read-out architecture. The TileCal detector signals will be digitized by on-detector electronics and transferred to the TileCal PreProcessors (TilePPr), which comprise the main component of the off-detector electronics. In the TilePPr, the digitized data will be stored in pipeline buffers and be packed and read out to the Front-End LInk eXchange (FELIX) system upon the reception of a trigger decision. FELIX is a new detector readout component being developed as part of the ATLAS upgrade effort. FELIX is designed to act as a data router between the data acquisition detector control and TTC (Timing, Trigger and Control) systems and the new or updated trigger and detector front-end electronics. Whereas previous detector readout implementations relied on diverse custom hardware platforms, the idea behind FELIX is to unify all readout across one well supported and flexible platform.

46

Gianotti, F. "Physics opportunities of the LHC luminosity upgrade." Nuclear Physics B - Proceedings Supplements 147 (October 2005): 23–32. http://dx.doi.org/10.1016/j.nuclphysbps.2005.03.004.

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47

Scandale, W. "Possible scenarios for the LHC luminosity upgrade." Nuclear Physics B - Proceedings Supplements 154, no. 1 (April 2006): 101–4. http://dx.doi.org/10.1016/j.nuclphysbps.2006.01.058.

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48

Cooke, Charlotte. "Upgrade of the CMS Barrel Electromagnetic Calorimeter for the High Luminosity LHC." Instruments 6, no. 3 (August 27, 2022): 29. http://dx.doi.org/10.3390/instruments6030029.

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The high luminosity upgrade of the LHC (HL-LHC) at CERN will provide unprecedented instantaneous and integrated luminosities of up to 7.5×1034 cm−2s−1 and 4500 fb−1, respectively, from 2029 onwards. To cope with the extreme conditions of up to 200 collisions per bunch crossing, and increased data rates, the on- and off-detector electronics of the CMS electromagnetic calorimeter (ECAL) will be replaced. A dual gain trans-impedance amplifier and an ASIC providing two 160 MHz ADC channels, gain selection, and data compression will be used. The lead tungstate crystals and avalanche photodiodes (APDs) in the current ECAL will keep performing well and will therefore be maintained. The noise increase in the APDs, due to radiation-induced dark currents, will be minimised by reducing the ECAL operating temperature from 18 °C to around 9 °C. Prototype HL-LHC electronics have been tested and have shown promising results. In two test beam periods using the CERN SPS H4 beamline and an electron beam, the new electronics achieved the target energy resolution and a timing resolution consistent that is consistent with our requirements of 30 ps timing for energies greater than 50 GeV.

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Saito, Masahiko, Paolo Calafiura, Heather Gray, Wim Lavrijsen, Lucy Linder, Yasuyuki Okumura, Ryu Sawada, Alex Smith, Junichi Tanaka, and Koji Terashi. "Quantum annealing algorithms for track pattern recognition." EPJ Web of Conferences 245 (2020): 10006. http://dx.doi.org/10.1051/epjconf/202024510006.

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The High-Luminosity Large Hadron Collider (HL-LHC) starts from 2027 to extend the physics discovery potential at the energy frontier. The HL-LHC produces experimental data with a much higher luminosity, requiring a large amount of computing resources mainly due to the complexity of a track pattern recognition algorithm. Quantum annealing might be a solution for an efficient track pattern recognition in the HL-LHC environment. We demonstrated to perform the track pattern recognition by using the D-Wave annealing machine and the Fujitsu Digital Annealer. The tracking efficiency and purity for the D-Wave quantum annealer are comparable with those for a classical simulated annealing at a low pileup condition, while a drop in performance is found at a high pileup condition, corresponding to the HL-LHC pileup environment. The tracking efficiency and purity for the Fujitsu Digital Annealer are nearly the same as the classical simulated annealing.

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Williams, T. "System design and prototyping of the CMS Level-1 Trigger at the High-Luminosity LHC." Journal of Instrumentation 19, no. 03 (March 1, 2024): C03016. http://dx.doi.org/10.1088/1748-0221/19/03/c03016.

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Abstract For the High-Luminosity LHC (HL-LHC) era, the trigger and data acquisition system of the CMS experiment will be entirely replaced. The HL-LHC CMS Level-1 Trigger system will consist of approximately 200 ATCA boards featuring Xilinx UltraScale+ FPGAs connected by 25 Gb/s optical links. These boards will process over 60 Tb/s of detector data within 9.5 μs of the collision to select up to 750 kHz of events for readout. In this paper, we summarise the current status of hardware tests, our progress on system integration tests, and the online software designed to control and monitor these boards.

Journal articles on the topic 'High luminosty LHC'

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