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1st FCC-ee TDAQ Workshop
No full textRate and occupancy studies, detector readout constraints, trigger considerations, and simila
Searches for VLQs and LQs from the ATLAS Experiment
No full textThe Standard Model of particle physics explains many natural phenomena yet remains incomplete. Vectorlike quarks and leptoquarks lie at the heart of many extensions to the Standard Model seeking to address the hierarchy problem, or the flavour sector anomalies. These proceedings present the new results from searches with the ATLAS detector at the LHC
Measurement of vector boson plus jets and multi-jets production in ATLAS
No full textTalk at Low-x 2025 Conferenc
Precision measurements of Drell-Yan processes in ATLAS
No full textPrecision measurements of Drell-Yan processes (both on-shell and off-shell W and Z bosons) offer key input to improve on the understanding of QCD and the accuracy of PDFs. In addition, these measurements are deeply linked with the achievements in electroweak parameter precision tests (such as W boson mass measurement). This talk will summarise recent achievements from ATLAS on this topic
Physics performance studies of the HGCAL trigger primitive generation system
No full textThis note presents recent developments and performance studies of the HGCAL Trigger Primitive Generation (TPG) system, with a primary focus on algorithmic strategies for assigning Module Sums and Trigger Cells or Super Trigger Cells (TCs/STCs) to Partial Trigger Towers (PTTs) in the Stage 1 of the HGCAL Backend. These strategies are designed to optimise energy reconstruction and achieve a precise, consistent mapping of detector signals to trigger primitives while respecting firmware constraints. By improving the accuracy and reliability of trigger primitives, these algorithms directly support Level-1 (L1) trigger decisions, enabling the reconstruction of higher-level physics objects such as electrons and jets and maintaining the physics performance required for the High-Luminosity phase of CMS
The Histogram Similarity Based Strategy for Performance Improvement of Multi-Class Classification with the Simulated CMS-HGCAL Data in Level-1 Trigger
No full textIn the upcoming High-Luminosity (HL) phase of the Large Hadron Collider (LHC), the rates of proton-proton collisions will increase significantly, resulting in a substantial amount of data, including soft collisions or pile-up (PU). This study develops an algorithm for real-time selection of significant collision data in the Level 1 Trigger (L1T) system for the High Granularity Calorimeter (HGCAL) in the Compact Muon Solenoid (CMS) detector upgraded for the HL era.
To conduct multi-class selection based on four types of data - electromagnetic showers (EM), PU, quantum chromodynamics (QCD) jets, and single pions, two machine learning architectures are explored: Convolutional Neural Networks (CNN) and Multi-Layer Perceptrons (MLP). In the first proposal, PU and QCD jets are merged to form a single background, leading to a weighted F1 score of 92\% for both models. Another approach incorporated additional features that represented the similarity of other particles/classes' HGCAL longitudinal profiles. Using Chebyshev distance to calculate these features, a weighted F1 score of 97\% is achieved for the CNN model. By integrating a mixed PU/QCD background with Chebyshev distance-based features, weighted F1 score improved to over 99\%.
Due to the limitations in the size of the models implemented on the targeted L1T device (Field Programmable Gate Array, FPGA), the final approach utilizes only the most important features as inputs, significantly reducing the model's size while maintaining accuracy. The simplified models are successfully implemented on the FPGA and can all be executed within a specified latency
Performance of the front-end electronics of the CMS electromagnetic calorimeter barrel for the High-Luminosity LHC
No full textThe performance of the CMS electromagnetic calorimeter upgraded readout electronics, developed for the High-Luminosity phase of the LHC, is discussed. Data collected in two beam test campaigns conducted in 2018 and 2021 at the H4 and H2 beam lines of the CERN SPS are analyzed. Time and energy resolutions are measured on a matrix of lead tungstate crystals equipped with prototypes of the new front end readout electronics, using electron and pion beams of energies spanning from 25 to 250 GeV. In both campaigns the constant term of the energy resolution is measured to be better than 0.6\% and the time resolutions for electrons with energies above 50 GeV is measured to be better than 30 ps, fulfilling the design requirements.The performance of the CMS electromagnetic calorimeter upgraded readout electronics, developed for the High-Luminosity phase of the LHC, is discussed. Data collected in two beam test campaigns conducted in 2018 and 2021 at the H4 and H2 beam lines of the CERN SPS are analyzed. Time and energy resolutions are measured on a matrix of lead tungstate crystals equipped with prototypes of the new front end readout electronics, using electron and pion beams of energies spanning from 25 to 250 GeV. In both campaigns the constant term of the energy resolution is measured to be better than 0.6% and the time resolution for electrons with energies above 50 GeV is measured to be better than 30 ps, fulfilling the design requirements
4th International Symposium on the History of Particle Physics
No full text4th International Symposium on the History of Particle Physic
Introduction of the forward Feature Extractor (fFEX) in the ATLAS first-level Trigger for the HL-LHC era
No full textWith the addition of the forward Feature Extractor (fFEX) during the High-Luminosity LHC (HL-LHC) upgrade, ATLAS will gain a new powerful first-level calorimeter trigger (L0Calo) subsystem that significantly enhances the trigger performance in the Forward Calorimeter (FCal) region. Utilising the full calorimeter granularity, fFEX will extend L0Calo's electromagnetic (EM) and tau trigger capabilities to the forward region, and will improve the jet reconstruction. The expected pile-up levels of up to 200 collisions per bunch crossing will increase the data background particulary in the forward region and making pile-up subtraction an essential task. The fFEX system will consist of 4 custom designed Advanced Telecommunications Computing Architecture (ATCA) boards, each hosting 2 powerful FPGA processors (AMD UltraScale+ VU13P) and 24 Samtec FireFly optical modules for high-speed (up to ~25.8 Gbps per link) data transmission for the real-time and the readout path. Each processor FPGA will process real-time data streams of 2.5 Tbps in total and within an latency limit of 500 ns. The identified jet, EM and hadronic tau candidates, and global quantities like Missing Transversal Energy (MEt) will be forwarded to the new Level-0 Global Processor (L0Global). In this presentation, we will give a detailed overview of the fFEX design, its hardware and firmware architecture, and share results of the first prototype's validation. We will highlight the role of fFEX in the preparation of the ATLAS calorimeter trigger for the challenging conditions of the HL-LHC era
