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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

A Web-based application for the collection, management and release of Alignment and Calibration configurations used in data processing at the Compact Muon Solenoid experiment

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.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The LHC Compact Muon Solenoid experiment detector control system

The Compact Muon Solenoid (CMS) experiment at CERN is a multi-purpose experiment designed to exploit the physics of proton-proton collisions at the Large Hadron Collider collision energy (14TeV at centre of mass) over the full range of expected luminosities (up to 10(34)cm(-')(2)s(-')(1)). The CMS detector control system (DCS) ensures a safe, correct and efficient operation of the detector so that high quality physics data can be recorded. The system is also required to operate the detector with a small crew of experts who can take care of the maintenance of its software and hardware infrastructure. The subsystems size sum up to more than a million parameters that need to be supervised by the DCS. A cluster of roughly 100 servers is used to provide the required processing resources. A scalable approach has been chosen factorizing the DCS system as much as possible. CMS DCS has made clear a division between its computing resources and functionality by creating a computing framework allowing plugging in of functional components. DCS components are developed by the subsystems expert groups while the computing infrastructure is developed centrally. To ensure the correct operation of the detector, DCS organizes the communication between the accelerator and the experiment systems making sure that the detector is in a safe state during hazardous situations and is fully operational when stable conditions are present. This paper describes the current status of the CMS DCS focusing on operational aspects and the role of DCS in this communication.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

The upgrade and re-validation of the Compact Muon Solenoid Electromagnetic Calorimeter Control and Safety Systems during the Second Long Shutdown of the Large Hadron Collider at CERN

The Electromagnetic Calorimeter (ECAL) is one of the subdetectors of the Compact Muon Solenoid (CMS), a general-purpose particle detector at the CERN Large Hadron Collider (LHC). The CMS ECAL Detector Control System (DCS) and the CMS ECAL Safety System (ESS) have supported the detector operations and ensured the detector’s integrity since the CMS commissioning phase, more than 10 years ago. Over this long period, several changes to both systems were necessary to correct issues, extend functionality and keep them in-line with current hardware technologies and the evolution of software platforms. Due to the constraints imposed on significant changes to a running system, major hardware and software upgrades were therefore deferred to the second LHC Long Shutdown (LS2). This paper presents the architectures of the CMS ECAL control and safety systems, discusses the ongoing and planned upgrades, details implementation processes and validation methods and highlights the expectations for the post-LS2 systems.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Search for New Physics with the Compact Muon Solenoid Experiment and QIS-enabled Technology

Understanding the fundamental nature of dark matter (DM)---its cosmological origin, constituents, and interactions---is one of the most important questions in fundamental science today. In this thesis, I present two novel and highly complementary approaches to cover the gaps in sensitivity of current DM searches. The searches are enabled by a first-of-its-kind reconstruction technique to search for hidden-sector particles using the Compact Muon Solenoid (CMS) and by new advances in quantum sensing technology to search for axions and hidden-sector DM. In the first part of this thesis, I present a search for long-lived hidden sector particles, predicted by many extensions of the SM, using a novel technique to reconstruct decays of long-lived particles (LLPs) in the CMS muon detector. The innovative LLP reconstruction technique is sensitive to a broad range of LLP decays and to LLP masses below GeV. The search yields competitive sensitivity for proper lifetime 0.1--1000 m with the full Run 2 dataset recorded at the LHC between 2016--2018 at $\sqrt{s} = 13~$TeV. To extend the physics reach of this novel muon detector shower (MDS) signature, I present the model-independence of MDS and the reinterpretation of the search to a large number of LLP models, demonstrating its complementarity with proposed and existing dedicated LLP experiments. Finally, I present a new dedicated MDS trigger that improves the trigger efficiency by at least an order of magnitude and was deployed in 2022, at the start of Run 3 of the LHC operations. In the second part of the thesis, I present for the first time, the use of a novel quantum sensor, the low-noise and single-photon sensitive superconducting nanowire single photon detectors (SNSPDs), to directly detect dark matter. The low detection threshold and ultra-low dark count rate of SNSPDs can close the gap in DM discovery reach due to the current limitations in detector sensitivity. I will present my work on the development and characterization of SNSPDs for two entirely new experiments to directly detect axions via absorption and hidden-sector DM via electron scattering. The search for axions employs a novel broadband reflector technique with the Broadband Reflector Experiment for Axion Detection (BREAD). A unique parabolic mirror is then used to focus axion-converted photons to the SNSPDs, extending the reach to axion masses of 0.04--1 eV. On the other hand, by coupling the SNSPDs with gallium arsenide, a bright cryogenic scintillator well matched to SNSPD detection, a prototype sensing system can be built as a basis of new direct DM detection experiments capable of extending the discovery to DM masses as low as 1 MeV.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

New Physics Search in Dijet Mass Spectrum with Compact Muon Solenoid

Many extensions of the SM predict the existence of new massive objects that couple to quarks and gluons and result in resonances in the dijet mass spectrum. In this thesis we present a search for narrow resonances in the dijet mass spectrum using data corresponding to an integrated luminosity of 1 fb$^{-1}$ collected by the CMS experiment at the LHC, at a proton-proton collision energy of $\sqrt{s}=7$ $TeV$. %This dijet analysis is searching for new particles in the dijet mass spectrum decaying to dijets. These new particles are predicted by new physics beyond Standard Model. This thesis presents a dijet analysis performed at the Compact Muon Solenoid (CMS) in pp collisions at $\sqrt{s}=7$ $TeV$ for an integrated luminosities of 1.0 fb$^{-1}$. The dijet mass distribution of two leading jets is measured and compared to QCD predictions, simulated by PYTHIA with the CMS detector simulation. We select events which have two leading jets with $\mid \Delta\eta \mid < 1.3$ and $\mid \eta \mid < 2.5$. We fit the dijet mass spectrum with QCD parameters. Since no evidence of new physics was found, we set upper limits at 95\% CL on the resonance cross section and compare to the theoretical prediction for several models of new particles: string resonances, axigluons, colorons, excited quarks, $E_{6}$ diquarks, Randall-Sundrum gravitons, W' and Z'. We exclude at 95\% CL string resonances in the mass range $1.0 < M(S) < 4.00$ TeV, excited quarks in the mass range $1.0<M(q*)<2.49$ TeV, axigluons and colorons in the mass range $1.0<M(A)<2.47$ TeV, $E_6$ diquarks in the mass range $1.0<M(D)<3.52$ TeV, and W' bosons in the mass range $1.0<M(W')<1.51$ TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of the Forward-Backward Asymmetry in $\gamma/Z$ boson to Dilepton Events in Compact Muon Solenoid at a Center-of-mass Energy of 7 TeV

The forward-backward asymmetry parameter (AFB) as a function of dilepton invariant mass in Z/γ* →l + l - (l=e or μ) at √s=7 TeV is measured using 2.2 fb -1 of pp collision data in 2011. The forward-backward asymmetry measurement is performed using muons within |η| < 2.1 and electrons within |η| < 2.4 in a wide mass range between 40 GeV/c 2 to 1000 GeV/c 2 . The forward-backward asymmetry is also measured for the first time in a large rapidity range of |η| < 5 with electrons using the CMS forward calorimeters and results in a less diluted A FB measurement, as expected. The forward-backward asymmetry parameters are unfolded in three stages, limited pre-FSR, full pre-FSR, and non-diluted stage in order to obtain parton level A FB . The muon and electron results are combined, and the individual and combined results are found to be consistent with the Standard Model prediction within statistical and systematic uncertainties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurement of the Forward-Backward Asymmetry in $\gamma/Z$ boson to Dilepton Events in Compact Muon Solenoid at a Center-of-mass Energy of 7 TeV

The forward-backward asymmetry parameter ($A_{\rm FB}$) as a function of dilepton invariant mass in $Z / \gamma^* \rightarrow l^+l^-$ ($l$=$e$ or $\mu$) at $\sqrt{s}$=7 TeV is measured using 2.2 fb$^{-1}$ of $pp$ collision data in 2011. The uncorrected (raw) $A_{\rm FB}$ and the corrected (unfolded) $A_{\rm FB}$ is performed in a wide mass range between 40 GeV/$c^{2}$ to 1000 GeV/$c^{2}$, and comparative studies and correction techniques with simulation are described in detail. We measure raw $A_{\rm FB}$ for the first time in a large rapidity range of 3 $<|\eta| <$ 5 with electrons using the forward calorimeters and achieve almost non-diluted $A_{\rm FB}$ result. The $A_{\rm FB}$ measurements with muons and electrons and their combination are consistent with the Standard Model (SM) prediction within uncertainties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

A Search for WW$\gamma$ and WZ$\gamma$ Triboson Production and Anomalous Quartic Gauge Couplings at $\sqrt{s}$ = 8 and 13~TeV within the Compact Muon Solenoid

An analysis probing for the standard model production of three electroweak vector bosons, WV$\gamma$ with V = W or Z gauge boson, is presented. The W boson decays leptonically to an electron or muon, or their respective antiparticle, paired with the appropriate neutrino. The second boson V decays hadronically into two jets, and additionally a photon is required in the event. The data analyzed correspond to an integrated luminosity of 19.6~fb$^{-1}$ and 2.3~fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 8~TeV and 13~TeV, respectively, collected in 2012 and 2015 by the CMS detector at the Large Hadron Collider. The event selection criteria used in these analyses yields 322 and 46 observed events in data in 2012 and 2015, respectively, while the estimated background yield from theoretical predictions is 342.1~$\pm$~22.2 and 54.3~$\pm$~17.7. These observations are consistent with the standard model next-to-leading order QCD predictions. Given the limitation in statistics to measure the cross section for this production process, an upper limit of 3.4 times the standard model predictions is made at a 95\% confidence level for WV$\gamma$ with photon $p_{T}$ greater than 30~GeV and absolute pseudorapidity less than 1.44. Physics beyond the standard model, such as anomalous couplings between the gauge bosons at the quartic vertex, may lead to enhancement in the number of WV$\gamma$ events produced within high energy collisions. Such enhancements can be observed in kinematic distributions, particularly in the higher energy regions. No evidence of anomalous WW$\gamma\gamma$ and WWZ$\gamma$ quartic gauge boson couplings is found, while 95\% confidence level upper limits are obtained for various couplings.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

A Search for New Resonances with the Dijet Angular Ratio Using the Compact Muon Solenoid Experiment

A search for dijet resonances is performed using 2.2 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 7 TeV recorded by the CMS detector at CERN. The study is based on the dijet angular ratio, the ratio of the number of events with the two leading jets having pseudorapidity difference |delta eta| < 1.3 to the number of events with 1.3 < |delta eta| < 3.0. Models of new resonances which decay into two jets typically predict dijet angular distributions and hence, values of the dijet angular ratio which differ from standard model processes. We thus use the measurement of the angular ratio as a function of mass to set limits on the cross sections of new spin -1/2 quark-gluon resonances. We exclude excited quarks of mass less than 3.2 TeV at 95% confidence level, where a limit of 2.8 TeV is expected.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Observation and studies of jet quenching in PbPb collisions at {radical}(s{sub NN})=2.76 TeV

Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the Compact Muon Solenoid (CMS) detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 {mu}b{sup -1}. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cutoff used in this study (jet p{sub T}=120 GeV/c) up to the statistical limit of the available data sample (jet p{sub T}{approx_equal}210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Fermilab Heroes of the LHC: Joel Butler

Particle physics research is both international and collaborative, with large national laboratories working together to most efficiently advance science. Joel Butler, Distinguished Scientist at Fermi National Accelerator Laboratory is the leader of the Compact Muon Solenoid experiment at the CERN laboratory in Europe. In this video, Joel tells us a bit about what it’s like.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

The science of "Spider-man: Into the Spider-Verse"

Science fiction sometimes borrows from science fact. In the movie “Spider-Man: Into the Spider-Verse,” the writers blended multiverses and alternate realities with the real world Large Hadron Collider and the Compact Muon Solenoid. In this video, Fermilab’s Dr. Don Lincoln gives you the low-down on what is real and what is made up.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Data Quality Monitoring for the Hadron Calorimeters Using Transfer Learning for Anomaly Detection

The proliferation of sensors brings an immense volume of spatio-temporal (ST) data in many domains, including monitoring, diagnostics, and prognostics applications. Data curation is a time-consuming process for a large volume of data, making it challenging and expensive to deploy data analytics platforms in new environments. Transfer learning (TL) mechanisms promise to mitigate data sparsity and model complexity by utilizing pre-trained models for a new task. Despite the triumph of TL in fields like computer vision and natural language processing, efforts on complex ST models for anomaly detection (AD) applications are limited. In this study, we present the potential of TL within the context of high-dimensional ST AD with a hybrid autoencoder architecture, incorporating convolutional, graph, and recurrent neural networks. Motivated by the need for improved model accuracy and robustness, particularly in scenarios with limited training data on systems with thousands of sensors, this research investigates the transferability of models trained on different sections of the Hadron Calorimeter of the Compact Muon Solenoid experiment at CERN. The key contributions of the study include exploring TL’s potential and limitations within the context of encoder and decoder networks, revealing insights into model initialization and training configurations that enhance performance while substantially reducing trainable parameters and mitigating data contamination effects.

47 OTHER INSTRUMENTATION↗
DOE OSTI2013

Search for heavy quarks decaying into a top quark and a W or Z boson using lepton + jets events in pp collisions at $ \sqrt{s}=7 $ TeV

Results are presented from a search for the pair-production of heavy quarks, Q Q-bar, that decay exclusively into a top quark and a W or Z boson. The search is performed using a sample of proton-proton collisions at $\sqrt{s}$ = 7 TeV corresponding to an integrated luminosity of 5.0 inverse femtobarns, collected by the Compact Muon Solenoid experiment. The signal region is defined using a sample of events containing one electron or muon, missing transverse momentum, and at least four jets with large transverse momenta, where one jet is likely to originate from the decay of a bottom quark. No significant excess of events is observed with respect to the standard model expectations. Assuming a strong pair-production mechanism, quark masses below 675 (625) GeV decaying into tW (tZ) are excluded at the 95% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Scintillating crystals for the Neutral Particle Spectrometer in Hall C at JLab

This report discusses the quality and performance of currently available PbWO crystals of relevance to high-resolution electromagnetic calorimetry, e.g. detectors for the Neutral Particle Spectrometer at Jefferson Lab or those planned for the Electron–Ion Collider. Since the construction of the Compact Muon Solenoid (CMS) at the Large Hadron Collider (LHC) and early PANDA (The antiProton ANnihilations at DArmstadt) electromagnetic calorimeter (ECAL) the worldwide availability of high quality PbWO 4 production has changed dramatically. We report on our studies of crystal samples from SICCAS/China and CRYTUR/Czech Republic that were produced between 2014 and 2019.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Performance of prototype GE1/1 chambers for the CMS muon spectrometer upgrade

The high-luminosity phase of the Large Hadron Collider (HL-LHC) will result in ten times higher particle background than measured during the first phase of LHC operation. In order to fully exploit the highly-demanding operating conditions during HL-LHC, the Compact Muon Solenoid (CMS) Collaboration will use Gas Electron Multiplier (GEM) detector technology. The technology will be integrated into the innermost region of the forward muon spectrometer of CMS as an additional muon station called GE1/1. The primary purpose of this auxiliary station is to help in muon reconstruction and to control level-1 muon trigger rates in the pseudo-rapidity region 1.6 ≤ |η| ≤ 2.2. The new station will contain trapezoidal-shaped GEM detectors called GE1/1 chambers. The design of these chambers is finalized, and the installation is in progress during the Long Shutdown phase two (LS-2) that started in 2019. Several full-size prototypes were built and operated successfully in various test beams at CERN. Here, we describe performance measurements such as gain, efficiency, and time resolution of these prototype chambers, developed after years of R&D, and summarize their behavior in different gas compositions as a function of the applied voltage.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Development of readout electronics for the CMS ME0 muon detector

The Large Hadron Collider (LHC) in the High Luminosity (HL-LHC) era will be upgraded to deliver instantaneous luminosities up to 5 X 10 34 cm -2 s -1 , five times more than the original design value. In order to maintain performance of the Compact Muon Solenoid (CMS) Experiment under these conditions, ME0 is one of the new muon detectors to be added, along with GE1/1, GE2/1, RE3/1 and RE4/1. ME0 uses the triple Gas Electron Multiplier (GEM) technology and is designed to cover the far-forward region of 2.0 < |η| < 2.8. Further, the readout electronics for ME0 must be designed to deal with high data rates and be sufficiently radiation hard to operate very close to the beamline. The design and development status of the readout electronics for ME0 are presented, along with recent results from integration tests performed using the latest electronics prototypes with GEM chambers.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

RPC background studies at CMS experiment

During Run2 the high instantaneous luminosity, up to 2.2 · 10 34 cm -2 s -1 , lead to a substantial hit rate in the Compact Muon Solenoid experiment’s muon chambers due to multiple background sources to physics processes sought for at LHC. In this article we will describe the analysis method devised to measure and identify the contributions to such background in the Resistive Plate Chambers. Thorough understanding of the background rates provides the base for the upgrade of the muon detectors for the High-Luminosity LHC.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗