# CMS Detector Performance Summaries

2019-07-12
16:01
 Results of DT Longevity Studies /CMS Collaboration The CMS drift tubes (DT) muon detector, built for standing up the LHC expected integrated and instantaneous luminosities, will be used also in the High Luminosity LHC (HL-LHC) at a 5 times larger instantaneous luminosity and, consequently, much higher levels of radiation, reaching about 10 times the LHC integrated luminosity. Initial irradiation tests of a spare DT chamber at the CERN gamma irradiation facility (GIF++), at large (about O(100)) acceleration factor, showed aging effects resulting in a degradation of the DT cell performance; however, full CMS simulations have shown almost no impact in the muon reconstruction efficiency over the full barrel acceptance and for the full integrated luminosity. [...] CMS-DP-2019-018; CERN-CMS-DP-2019-018.- Geneva : CERN, 2019 - 11 p. Fulltext: PDF;

2019-07-12
12:03
 CMS ECAL Timing Resolution Performance with Run 2 data /CMS Collaboration The CMS electromagnetic calorimeter (ECAL) is made of about 75000 scintillating lead tungstate crystals arranged in a barrel and two endcaps. The scintillation light is read out by avalanche photodiodes in the barrel and vacuum photodiodes in the endcaps, at which point the scintillation pulse is amplified and sampled at 40 MHz by the on-detector electronics [...] CMS-DP-2019-021; CERN-CMS-DP-2019-021.- Geneva : CERN, 2019 - 8 p. Fulltext: PDF;

2019-07-12
12:03
 Level-1 E/Gamma trigger performance in Run II /CMS Collaboration In this note, the performance of the CMS Level-1 E/Gamma trigger during LHC Run II data taking period is presented. The results are obtained using LHC proton-proton collision data recorded by the CMS detector during 2016, 2017 and 2018, at $\mathrm{\sqrt{s}=13 \ TeV}$, corresponding to an integrated luminosity of 35.9 $\mathrm{fb^{-1}}$, 41.3 $\mathrm{fb^{-1}}$ and 58.8 $\mathrm{fb^{-1}}$ respectively.. CMS-DP-2019-020; CERN-CMS-DP-2019-020.- Geneva : CERN, 2019 - 13 p. Fulltext: PDF;

2019-07-09
14:09
 Relative non-linearity of BRIL luminometers derived from CMS mu-scans /CMS Collaboration The CMS Beam Radiation Instrumentation and Luminosity Project (BRIL) is devoted to the simulation and measurement of beam conditions and luminosity for CMS. The project is engaged in operating and developing new detectors, compatible with the high luminosity experimental environments at the LHC. [...] CMS-DP-2019-014; CERN-CMS-DP-2019-014.- Geneva : CERN, 2019 - 7 p. Fulltext: PDF;

2019-07-09
14:08
 Long-term monitoring of delivered luminosity & calibration stability in CMS /CMS Collaboration Lumi days 2019 presentation. Indico https://indico.cern.ch/event/813285/timetable/ Uncertainty of the delivered luminosity in years 2017 and 2018 due to stability and linearity is discussed. [...] CMS-DP-2019-016; CERN-CMS-DP-2019-016.- Geneva : CERN, 2019 - 17 p. Fulltext: PDF;

2019-07-09
14:08
 Understanding of the beam emittance evolution during SB /CMS Collaboration Lumi days 2019 presentation. Indico https://indico.cern.ch/event/813285/timetable/ CMS emittance scans can be used to measure emittance evolution of the beam. [...] CMS-DP-2019-017; CERN-CMS-DP-2019-017.- Geneva : CERN, 2019 - 17 p. Fulltext: PDF;

2019-07-09
14:08
 Nonfactorization in Van der Meer scans in Run 2 /CMS Collaboration The luminosity measurement of the CMS experiment is calibrated with Van der Meer (VdM) scans in special LHC fills. From two such scans in orthogonal directions (along the $x$ and $y$ axis of the CMS coordinate system), the overlap area of the proton density of the two beams is measured. [...] CMS-DP-2019-019; CERN-CMS-DP-2019-019.- Geneva : CERN, 2019 - 33 p. Fulltext: PDF;

2019-06-18
16:26
 Comparison of ATLAS and CMS nominal $\mathrm{t}\mathrm{\bar t}$ Monte Carlo simulation for Run 2 /ATLAS and CMS Collaborations A preliminary study is performed to compare the Monte Carlo simulation of $\mathrm{t}\mathrm{\bar t}$ events at 13 TeV employed by the ATLAS and CMS experiments. The study focuses on the nominal settings used in each experiment, consisting in interfacing Powheg-box with Pythia8 (v 8.230) using the corresponding ATLAS and CMS experimental tunes. [...] CMS-DP-2019-011; CERN-CMS-DP-2019-011.- Geneva : CERN, 2019 - 13 p. Fulltext: PDF;

2019-06-18
16:26
 Tau Lepton Run 2 Trigger Performance /CMS Collaboration Triggers selecting events with hadronically decaying tau leptons $\tau_h$ are used in a wide variety of CMS analyses, in particular those targeting processes with a $H \rightarrow \tau\tau$ decay. The performance of the $\tau_h$ triggers is presented for data collected in Run 2 corresponding to an integrated luminosity of 137.1 fb$^{-1}$ at 13 TeV, and compared with simulation.. CMS-DP-2019-012; CERN-CMS-DP-2019-012.- Geneva : CERN, 2019 - 21 p. Fulltext: PDF;

2019-05-07
16:38
 Performance of the CMS Drift Tubes at the end of LHC Run 2 /CMS Collaboration This note summarizes the performance of Drift Tubes (DT) at the end of 2018 data-taking. Results are shown for efficiency of hit detection, track segment reconstruction, trigger primitive generation. Trends of these efficiencies were also checked as a function of integrated luminosity (or time) and of instantaneous luminosity, in order to spot any effects of degradation caused by detector ageing or by background, respectively. Figures for present DT space and time resolution are also presented. This set of plots is proposed as reference for future Run 3 data-taking.. CMS-DP-2019-008; CERN-CMS-DP-2019-008.- Geneva : CERN, 2019 - 27 p. External link: Fulltext