Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
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Article Citation - WoS: 11Citation - Scopus: 13The Very Forward Castor Calorimeter of the Cms Experiment(Institute of Physics, 2021) Khachatryan,V.; Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Smirnov,I.The physics motivation, detector design, triggers, calibration, alignment, simulation, and overall performance of the very forward CASTOR calorimeter of the CMS experiment are reviewed. The CASTOR Cherenkov sampling calorimeter is located very close to the LHC beam line, at a radial distance of about 1cm from the beam pipe, and at 14.4m from the CMS interaction point, covering the pseudorapidity range of -6.6 < η < -5.2. It was designed to withstand high ambient radiation and strong magnetic fields. The performance of the detector in measurements of forward energy density, jets, and processes characterized by rapidity gaps, is reviewed using data collected in proton and nuclear collisions at the LHC. © 2021 CERN for the benefit of the CMS collaboration..Article Citation - WoS: 154Citation - Scopus: 174Pileup Mitigation at Cms in 13 Tev Data(Institute of Physics, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Belyaev, A.With increasing instantaneous luminosity at the LHC come additional reconstruction challenges. At high luminosity, many collisions occur simultaneously within one proton-proton bunch crossing. The isolation of an interesting collision from the additional "pileup"collisions is needed for effective physics performance. In the CMS Collaboration, several techniques capable of mitigating the impact of these pileup collisions have been developed. Such methods include charged-hadron subtraction, pileup jet identification, isospin-based neutral particle "δβ"correction, and, most recently, pileup per particle identification. This paper surveys the performance of these techniques for jet and missing transverse momentum reconstruction, as well as muon isolation. The analysis makes use of data corresponding to 35.9 fb-1 collected with the CMS experiment in 2016 at a center-of-mass energy of 13 TeV. The performance of each algorithm is discussed for up to 70 simultaneous collisions per bunch crossing. Significant improvements are found in the identification of pileup jets, the jet energy, mass, and angular resolution, missing transverse momentum resolution, and muon isolation when using pileup per particle identification. © 2020 CERN for the benefit of the CMS collaboration..Review Citation - WoS: 4Citation - Scopus: 6Calibration of the Cms Hadron Calorimeters Using Proton-Proton Collision Data at S = 13 Tev(Institute of Physics, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Klyukhin, V.Methods are presented for calibrating the hadron calorimeter system of the CMS detector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities |η| < 3 and are positioned inside the solenoidal magnet. An outer calorimeter, outside the magnet coil, covers |η| < 1.26, and a steel and quartz-fiber Cherenkov forward calorimeter extends the coverage to |η| < 5.19. The initial calibration of the calorimeters was based on results from test beams, augmented with the use of radioactive sources and lasers. The calibration was improved substantially using proton-proton collision data collected at s = 7, 8, and 13 TeV, as well as cosmic ray muon data collected during the periods when the LHC beams were not present. The present calibration is performed using the 13 TeV data collected during 2016 corresponding to an integrated luminosity of 35.9 fb-1. The intercalibration of channels exploits the approximate uniformity of energy collection over the azimuthal angle. The absolute energy scale of the central and endcap calorimeters is set using isolated charged hadrons. The energy scale for the electromagnetic portion of the forward calorimeters is set using Z→ ee data. The energy scale of the outer calorimeters has been determined with test beam data and is confirmed through data with high transverse momentum jets. In this paper, we present the details of the calibration methods and accuracy. © 2020 CERN for the benefit of the CMS collaboration..Article Citation - WoS: 143Citation - Scopus: 143Energy Calibration and Resolution of the Cms Electromagnetic Calorimeter in Pp Collisions at ?s = 7 Tev(IOP Publishing Ltd., 2013) CMS Collaboration; Karapınar, GülerThe energy calibration and resolution of the electromagnetic calorimeter (ECAL) of the CMS detector have been determined using proton-proton collision data from LHC operation in 2010 and 2011 at a centre-of-mass energy of √s = 7 TeV with integrated luminosities of about 5fb-1. Crucial aspects of detector operation, such as the environmental stability, alignment, and synchronization, are presented. The in-situ calibration procedures are discussed in detail and include the maintenance of the calibration in the challenging radiation environment inside the CMS detector. The energy resolution for electrons from Z-boson decays is better than 2% in the central region of the ECAL barrel (for pseudorapidity |η| < 0.8) and is 2-5% elsewhere. The derived energy resolution for photons from 125 GeV Higgs boson decays varies across the barrel from 1.1% to 2.6% and from 2.2% to 5% in the endcaps. The calibration of the absolute energy is determined from Ze→+e - decays to a precision of 0.4% in the barrel and 0.8% in the endcaps. © 2013 CERN for the benefit of the CMS collaboration.Article Citation - WoS: 44Citation - Scopus: 88Performance and Operation of the Cms Electromagnetic Calorimeter(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerThe operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75 848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented. © 2010 IOP Publishing Ltd and SISSA.Article Citation - WoS: 34Citation - Scopus: 42Performance of Cms Hadron Calorimeter Timing and Synchronization Using Test Beam, Cosmic Ray, and Lhc Beam Data(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerThis paper discusses the design and performance of the time measurement technique and of the synchronization systems of the CMS hadron calorimeter. Time measurement performance results are presented from test beam data taken in the years 2004 and 2006. For hadronic showers of energy greater than 100 GeV, the timing resolution is measured to be about 1.2 ns. Time synchronization and out-of-time background rejection results are presented from the Cosmic Run At Four Tesla and LHC beam runs taken in the Autumn of 2008. The inter-channel synchronization is measured to be within 2 ns. © 2010 IOP Publishing Ltd and SISSA.Article Citation - WoS: 33Citation - Scopus: 44Measurement of the Muon Stopping Power in Lead Tungstate(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerA large sample of cosmic ray events collected by the CMS detector is exploited to measure the specific energy loss of muons in the lead tungstate (PbWO4) of the electromagnetic calorimeter. The measurement spans a momentum range from 5 GeV/c to 1 TeV/c. The results are consistent with the expectations over the entire range. The calorimeter energy scale, set with 120 GeV/c electrons, is validated down to the sub-GeV region using energy deposits, of order 100 MeV, associated with low-momentum muons. The muon critical energy in PbWO4 is measured to be 160+5 -68 GeV, in agreement with expectations. This is the first experimental determination of muon critical energy. © 2010 IOP Publishing Ltd and SISSA.Article Citation - WoS: 54Citation - Scopus: 49Performance of the Cms Hadron Calorimeter With Cosmic Ray Muons and Lhc Beam Data(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerThe CMS Hadron Calorimeter in the barrel, endcap and forward regions is fully commissioned. Cosmic ray data were taken with and without magnetic field at the surface hall and after installation in the experimental hall, hundred meters underground. Various measurements were also performed during the few days of beam in the LHC in September 2008. Calibration parameters were extracted, and the energy response of the HCAL determined from test beam data has been checked. © 2010 IOP Publishing Ltd and SISSA.Article Citation - WoS: 49Citation - Scopus: 66Time Reconstruction and Performance of the Cms Electromagnetic Calorimeter(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerThe resolution and the linearity of time measurements made with the CMS electromagnetic calorimeter are studied with samples of data from test beam electrons, cosmic rays, and beam-produced muons. The resulting time resolution measured by lead tungstate crystals is better than 100 ps for energy deposits larger than 10 GeV. Crystal-to-crystal synchronization with a precision of 500 ps is performed using muons produced with the first LHC beams in 2008. © 2010 IOP Publishing Ltd and SISSA.Article Citation - WoS: 80Citation - Scopus: 81Identification and Filtering of Uncharacteristic Noise in the Cms Hadron Calorimeter(IOP Publishing Ltd., 2010) Demir, Durmuş Ali; Karapınar, GülerCommissioning studies of the CMS hadron calorimeter have identified sporadic uncharacteristic noise and a small number of malfunctioning calorimeter channels. Algorithms have been developed to identify and address these problems in the data. The methods have been tested on cosmic ray muon data, calorimeter noise data, and single beam data collected with CMS in 2008. The noise rejection algorithms can be applied to LHC collision data at the trigger level or in the offline analysis. The application of the algorithms at the trigger level is shown to remove 90% of noise events with fake missing transverse energy above 100 GeV, which is sufficient for the CMS physics trigger operation.