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CMS high-level trigger selection

Giuseppe Bagliesi
2004 European Physical Journal C: Particles and Fields  
The CMS High-Level Trigger (HLT) is based on sets of dedicated commercial processors, whose goal is to reduce the Level-1 trigger rate of 100 kHz to ≈100 Hz, a value compatible with permanent storage of data. In this report the results from the recently published DAQ TDR are presented. The offline code with little modifications can be used in the trigger chain soon after Level 1 by making use of regional and conditional analyses. For the benchmark channels considered, the signal efficiencies
more » ... background rejection factors, obtained within ≈500 ms of a recent CPU (1 GHz processor), are competitive with full offline analyses done without any timing limitation.
doi:10.1140/epjcd/s2004-03-1804-1 fatcat:osced4cz5ff65p6ckmdkk7ia34

Grid site availability evaluation and monitoring at CMS

Gaston Lyons, Rokas Maciulaitis, Giuseppe Bagliesi, Stephan Lammel, Andrea Sciabà
2017 Journal of Physics, Conference Series  
The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) uses distributed grid computing to store, process, and analyse the vast quantity of scientific data recorded every year. The computing resources are grouped into sites and organized in a tiered structure. Each site provides computing and storage to the CMS computing grid. Over a hundred sites worldwide contribute with resources from hundred to well over ten thousand computing cores and storage from tens of TBytes to
more » ... ns of PBytes. In such a large computing setup scheduled and unscheduled outages occur continually and are not allowed to significantly impact data handling, processing, and analysis. Unscheduled capacity and performance reductions need to be detected promptly and corrected. CMS developed a sophisticated site evaluation and monitoring system for Run 1 of the LHC based on tools of the Worldwide LHC Computing Grid. For Run 2 of the LHC the site evaluation and monitoring system is being overhauled to enable faster detection/reaction to failures and a more dynamic handling of computing resources. Enhancements to better distinguish site from central service issues and to make evaluations more transparent and informative to site support staff are planned.
doi:10.1088/1742-6596/898/9/092014 fatcat:oqqbw72pjnfgpmbxhbwoi7g4da

Consolidating WLCG topology and configuration in the Computing Resource Information Catalogue

Maria Alandes, Julia Andreeva, Alexey Anisenkov, Giuseppe Bagliesi, Stephano Belforte, Simone Campana, Maria Dimou, Jose Flix, Alessandra Forti, A di Girolamo, Edward Karavakis, Stephan Lammel (+3 others)
2017 Journal of Physics, Conference Series  
doi:10.1088/1742-6596/898/9/092042 fatcat:jvi5tunscnchpaaooohyh6btoa

Distributed Analysis in CMS

Alessandra Fanfani, Anzar Afaq, Jose Afonso Sanches, Julia Andreeva, Giusepppe Bagliesi, Lothar Bauerdick, Stefano Belforte, Patricia Bittencourt Sampaio, Ken Bloom, Barry Blumenfeld, Daniele Bonacorsi, Chris Brew (+67 others)
2010 Journal of Grid Computing  
The CMS experiment expects to manage several Pbytes of data each year during the LHC programme, distributing them over many A. Fanfani et al. location for physics analysis to support a wide community with thousands potential users. This represents an unprecedented experimental challenge in terms of the scale of distributed computing resources and number of user. An overview of the computing architecture, the software tools and the distributed infrastructure is reported. Summaries of the
more » ... ce in establishing efficient and scalable operations to get prepared for CMS distributed analysis are presented, followed by the user experience in their current analysis activities.
doi:10.1007/s10723-010-9152-1 fatcat:jvs2ccg7r5em7b3vringhmobye

Integration of the Italian cache federation within the CMS computing model

Diego Ciangottini, Giuseppe Bagliesi, Massimo Biasotto, Tommaso Boccali, Daniele CESINI, Giacinto DONVITO, Antonio Falabella, Enrico Mazzoni, Daniele Spiga, Mirco Tracolli
2019 Proceedings of International Symposium on Grids & Clouds 2019 — PoS(ISGC2019)   unpublished
The next decades at HL-LHC will be characterized by a huge increase of both storage and computing requirements (between one and two orders of magnitude). Moreover we foresee a shift on resources provisioning towards the exploitation of dynamic (on private or public cloud and HPC facilities) solutions. In this scenario the computing model of the CMS experiment is pushed towards an evolution for the optimization of the amount of space that is managed centrally and the CPU efficiency of the jobs
more » ... at run on "storage-less" resources. In particular the computing resources of the "Tier2" sites layer, for the most part, can be instrumented to read data from a geographically distributed cache storage based on unmanaged resources, reducing, in this way, the operational efforts by a large fraction and generating additional flexibility. The objective of this contribution is to present the first implementation of an INFN federation of cache servers, developed also in collaboration with the eXtreme Data Cloud EU project. The CNAF Tier-1 plus Bari and Legnaro Tier-2s provide unmanaged storages which have been organized under a common namespace. This distributed cache federation has been seamlessly integrated in the CMS computing infrastructure, while the technical implementation of this solution is based on XRootD, largely adopted in the CMS computing model under the "Anydata, Anytime, Anywhere project" (AAA). The results in terms of CMS workflows performances will be shown. In addition a complete simulation of the effects of the described model under several scenarios, including dynamic hybrid cloud resource provisioning, will be discussed. Finally a plan for the upgrade of such a prototype towards a stable INFN setup seamlessly integrated with production CMS computing infrastructure will be discussed.
doi:10.22323/1.351.0014 fatcat:evkjdhegxjfq3da66asswibvkm

MSSM Higgs searches with tau lepton final states in CMS

S. Gennai
2003 Nuclear Physics B - Proceedings Supplements  
Lassilla-Perini and Giuseppe Bagliesi for useful advice and for providing the illustration.  ... 
doi:10.1016/s0920-5632(03)02184-4 fatcat:k3c2mhwmwjejjdx2gdhlyhdwri

A Grid job monitoring system

Catalin Dumitrescu, Andreas Nowack, Sanjay Padhi, Subir Sarkar
2010 Journal of Physics, Conference Series  
Acknowledgement The authors are thankful to Giuseppe Bagliesi, Jon Bakken, Stefano Belforte, Giacinto Donvito, Igor Sfiligoi and Frank Würthwein for many helpful suggestions and support.  ... 
doi:10.1088/1742-6596/219/7/072051 fatcat:x47vzhy7jvfmzis3ljnbob5bm4

A Roadmap for HEP Software and Computing R&D for the 2020s

Johannes Albrecht, Antonio Augusto Alves, Guilherme Amadio, Giuseppe Andronico, Nguyen Anh-Ky, Laurent Aphecetche, John Apostolakis, Makoto Asai, Luca Atzori, Marian Babik, Giuseppe Bagliesi, Marilena Bandieramonte (+298 others)
2019 Computing and Software for Big Science  
Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the
more » ... ftware goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.
doi:10.1007/s41781-018-0018-8 fatcat:xuvdsxgmjfe7zah4vbvpazao2i

Evidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at $\sqrt {s_{NN}}$=5.02 TeV

Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam, Federico Ambrogi, Thomas Bergauer, Marko Dragicevic, Janos Erö, Alberto Escalante Del Valle, Martin Flechl, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer (+2297 others)
2022 Physical review letters 128(3)  
The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (Pb-Pb) collisions at a center-of-mass energy of ffiffiffiffiffiffiffi ffi s NN p ¼ 5.02 TeV per nucleon pair, using the decay chain Xð3872Þ The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7 nb −1 . The measurement is performed in the rapidity and transverse momentum ranges jyj < 1.6 and 15 < p T < 50
more » ... . The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to ψ2S yield ratio is found to be ρ Pb-Pb ¼ 1.08 AE 0.49ðstatÞ AE 0.52ðsystÞ, to be compared with typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.
doi:10.18154/rwth-2022-01812 fatcat:cxr6lwqqyjhhrfpbxh4zybiz74

Observation of a New Excited Beauty Strange Baryon Decaying to$\Xi^-_\mathrm{b} \pi^+ \pi^-$

Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam, Janik Walter Andrejkovic, Thomas Bergauer, Suman Chatterjee, Marko Dragicevic, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner (+2354 others)
2021 Physical review letters 126(25)  
The Ξ − b π þ π − invariant mass spectrum is investigated with an event sample of proton-proton collisions at ffiffi ffi s p ¼ 13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb −1 . The ground state Ξ − b is reconstructed via its decays to J=ψΞ − and J=ψΛK MeV, where the last uncertainty reflects the precision of the Ξ − b baryon mass. The upper limit on the Ξ b ð6100Þ − natural width is determined to be 1.9 MeV at 95%
more » ... nce level. The low Ξ b ð6100Þ − signal yield observed in data does not allow a measurement of the quantum numbers of the new state. However, following analogies with the established excited Ξ c baryon states, the new Ξ b ð6100Þ − resonance and its decay sequence are consistent with the orbitally excited Ξ − b baryon, with spin and parity quantum numbers J P ¼ 3=2 − .
doi:10.18154/rwth-2021-10773 fatcat:jebivqmfpvgxbb7odn7phd5am4

Search for long-lived particles decaying in the CMS endcap muon detectors in proton-proton collisions at $\sqrt{s} = $ 13 TeV

Armen Tumasyan, Wolfgang Adam, Janik Walter Andrejkovic, Thomas Bergauer, Suman Chatterjee, Marko Dragicevic, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner, Dietrich Liko (+2354 others)
2021 Physical review letters 127(26)  
A search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} =$ 13 TeV, recorded at the LHC in 2016-2018. A novel technique is employed to reconstruct decays of LLPs in the endcap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent
more » ... imits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and $\tau^+\tau^-$ are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectively.
doi:10.3204/pubdb-2022-00238 fatcat:cfvh4j2wxbce5lnd33tz4e6rde

Constraints on the Initial State of Pb-Pb Collisions via Measurements of $Z$-Boson Yields and Azimuthal Anisotropy at $\sqrt {s_{NN}}$=5.02 TeV

Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam, Federico Ambrogi, Thomas Bergauer, Marko Dragicevic, Janos Erö, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner (+2333 others)
2021 Physical review letters 127(10)  
doi:10.18154/rwth-2021-09930 fatcat:en4xeka2bbhohmvzb5ndftqfby

Search for Long-Lived Particles Decaying in the CMS End Cap Muon Detectors in Proton-Proton Collisions at $\sqrt s$ =13 TeV

Armen Tumasyan, Wolfgang Adam, Janik Walter Andrejkovic, Thomas Bergauer, Suman Chatterjee, Marko Dragicevic, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner, Dietrich Liko (+2354 others)
2021 Physical review letters 127(26)  
A search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137 fb −1 of proton-proton collisions at ffiffi ffi s p ¼ 13 TeV, recorded at the LHC in 2016-2018. A novel technique is employed to reconstruct decays of LLPs in the end cap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent
more » ... limits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and τ þ τ − are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectively.
doi:10.18154/rwth-2022-01524 fatcat:vy4sp662pnacvi5jigotju5tki

Search for long-lived particles produced in association with a Z boson in proton-proton collisions at $ \sqrt{s} $ = 13 TeV

Armen Tumasyan, Wolfgang Adam, Janik Walter Andrejkovic, Thomas Bergauer, Suman Chatterjee, Marko Dragicevic, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner, Dietrich Liko (+2360 others)
2022 Journal of high energy physics : JHEP 2022(3)  
A search for long-lived particles (LLPs) produced in association with a Z boson is presented. The study is performed using data from proton-proton collisions with a center-of-mass energy of 13 TeV recorded by the CMS experiment during 2016-2018, corresponding to an integrated luminosity of 117 fb −1 . The LLPs are assumed to decay to a pair of standard model quarks that are identified as displaced jets within the CMS tracker system. Triggers and selections based on Z boson decays to electron or
more » ... muon pairs improve the sensitivity to light LLPs (down to 15 GeV). This search provides sensitivity to beyond the standard model scenarios which predict LLPs produced in association with a Z boson. In particular, the results are interpreted in the context of exotic decays of the Higgs boson to a pair of scalar LLPs (H → SS). The Higgs boson decay branching fraction is constrained to values less than 6% for proper decay lengths of 10-100 mm and for LLP masses between 40 and 55 GeV. In the case of low-mass (≈ 15 GeV) scalar particles that subsequently decay to a pair of b quarks, the search is sensitive to branching fractions B(H → SS) < 20% for proper decay lengths of 10-50 mm. The use of associated production with a Z boson increases the sensitivity to low-mass LLPs of this analysis with respect to gluon fusion searches. In the case of 15 GeV scalar LLPs, the improvement corresponds to a factor of 2 at a proper decay length of 30 mm.
doi:10.18154/rwth-2022-04119 fatcat:lvuxj2rhvfbyjaaupgjw5cbbna

Measurement of the inclusive and differential Higgs boson production cross sections in the decay mode to a pair of $\tau$ leptons in pp collisions at $\sqrt{s} = $ 13 TeV

Armen Tumasyan, Wolfgang Adam, Janik Walter Andrejkovic, Thomas Bergauer, Suman Chatterjee, Marko Dragicevic, Alberto Escalante Del Valle, Rudolf Fruehwirth, Manfred Jeitler, Natascha Krammer, Lukas Lechner, Dietrich Liko (+2350 others)
2022 Physical review letters : PRL 128(8)  
leading order with the MLM jet matching and merging scheme [24] for the simulation of data taken in 2016 (2017 and 2018). It is also used to model the diboson production at NLO in (α S ), whereas POWHEG 2.0 and 1.0 are used for t t and single top quark production, respectively. Single top quark production in the t-channel and diboson events are normalized to their cross sections at NLO precision or higher [25, 26] . Drell-Yan events, as well as t t events and single top quark production in the
more » ... W channel, are normalized to their cross sections at NNLO precision [27, 28] . The generators are interfaced with PYTHIA8.212 [29] to model the parton showering and fragmentation, as well as the decay of the τ leptons. The PYTHIA tunes CUETP8M1 and CUETP8M4 [30] are used in simulation corresponding to the 2016 data-taking conditions, and the CP5 tune [31] is used for 2017 and 2018 simulations. The parton density function (PDF) set is NNPDF3.0 for 2016 simulations, and NNPDF 3.1 for 2017 and 2018 simulations [32] [33] [34] . Additional proton-proton interactions per bunch crossing, called pileup, are added to the simulations with the profile observed in data. Simulated events are processed through a GEANT4 [35] simulation of the CMS detector. The particle-flow (PF) algorithm [36] is used to reconstruct the events on the basis of information from the different CMS subdetectors. Muons are reconstructed from tracks and hits in the tracker and muon systems [37, 38] . Electrons are reconstructed from tracks in the tracking system and calorimeter deposits, and identified with a multivariate discriminant described in Ref. [39] . The relative isolation of electrons (muons) is calculated on the basis of the p T of tracks in a cone of ΔR ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi ðΔηÞ 2 þ ðΔϕÞ 2 p < 0.3 (0.4) centered on the lepton track, corrected for charged and neutral pileup contributions; it is required to be less than 0.15. Jets are clustered from PF candidates using the anti-(k T ) FASTJET algorithm with distance parameter R of 0.4 [40, 41], requiring p T > 30 GeV and jηj < 4.7. Jet energy corrections are applied on an event-by-event basis [36, 42, 43]. In events collected in 2017, jets with p T < 50 GeV and 2.65 < jηj < 3.14 are discarded to eliminate spurious jets caused by detector noise. Hadronic jets originating from b quarks are tagged
doi:10.18154/rwth-2022-03903 fatcat:wimvbnpqb5gstcqo5aiyueyhpq
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