WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 31Citation - Scopus: 65The Performance of the Cms Muon Detector in Proton-Proton Collisions at Root S=7 Tev at the Lhc(IOP Publishing Ltd., 2013) Karapınar, GülerThe performance of all subsystems of the CMS muon detector has been studied by using a sample of proton-proton collision data at root s = 7TeV collected at the LHC in 2010 that corresponds to an integrated luminosity of approximately 40 pb(-1). The measured distributions of the major operational parameters of the drift tube (DT), cathode strip chamber (CSC), and resistive plate chamber (RPC) systems met the design specifications. The spatial resolution per chamber was 80-120 mu m in the DTs, 40-150 mu m in the CSCs, and 0.8-1.2 cm in the RPCs. The time resolution achievable was 3 ns or better per chamber for all 3 systems. The efficiency for reconstructing hits and track segments originating from muons traversing the muon chambers was in the range 95-98%. The CSC and DT systems provided muon track segments for the CMS trigger with over 96% efficiency, and identified the correct triggering bunch crossing in over 99.5% of such events. The measured performance is well reproduced by Monte Carlo simulation of the muon system down to the level of individual channel response. The results confirm the high efficiency of the muon system, the robustness of the design against hardware failures, and its effectiveness in the discrimination of backgrounds.Article Citation - WoS: 31Citation - Scopus: 32Alignment of the Cms Tracker With Lhc and Cosmic Ray Data(IOP Publishing Ltd., 2014) Karapınar, Güler; Demir, Durmuş AliThe central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous determination of up to 200 000 alignment parameters with tracks, the measurement of individual sensor curvature parameters, the control of systematic misalignment effects, and the implementation of the whole procedure in a multiprocessor environment for high execution speed. Overall, the achieved statistical accuracy on the module alignment is found to be significantly better than 10 mu m.Article Citation - WoS: 456Citation - Scopus: 423Description and Performance of Track and Primary-Vertex Reconstruction With the Cms Tracker(IOP Publishing Ltd., 2014) Demir, Durmuş Ali; CMS CollaborationA description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For t (t) over bar events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of p(T) > 0.9GeV is 94% for pseudorapidities of vertical bar eta vertical bar < 0.9 and 85% for 0.9 < vertical bar eta vertical bar < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of p(T) = 100GeV emitted at vertical bar eta vertical bar < 1.4, the resolutions are approximately 2.8% in p(T), and respectively, 10 m m and 30 mu m in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10-12 mu m in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung.Article Citation - WoS: 105Citation - Scopus: 79Performance of the Cms Missing Transverse Momentum Reconstruction in Pp Data at Root S=8 Tev(IOP Publishing Ltd., 2015) Demir, Durmuş Ali; CMS CollaborationThe performance of missing transverse energy reconstruction algorithms is presented using root s = 8 TeV proton-proton (pp) data collected with the CMS detector. Events with anomalous missing transverse energy are studied, and the performance of algorithms used to identify and remove these events is presented. The scale and resolution for missing transverse energy, including the effects of multiple pp interactions (pileup), are measured using events with an identified Z boson or isolated photon, and are found to be well described by the simulation. Novel missing transverse energy reconstruction algorithms developed specifically to mitigate the effects of large numbers of pileup interactions on the missing transverse energy resolution are presented. These algorithms significantly reduce the dependence of the missing transverse energy resolution on pileup interactions. Finally, an algorithm that provides an estimate of the significance of the missing transverse energy is presented, which is used to estimate the compatibility of the reconstructed missing transverse energy with a zero nominal value.Article Citation - WoS: 458Citation - Scopus: 409Performance of Electron Reconstruction and Selection With the Cms Detector in Proton-Proton Collisions at Root S=8 Tev(IOP Publishing Ltd., 2015) Karapınar, GülerThe performance and strategies used in electron reconstruction and selection at CMS are presented based on data corresponding to an integrated luminosity of 19.7 fb(-1), collected in proton-proton collisions at root s = 8TeV at the CERN LHC. The paper focuses on prompt isolated electrons with transverse momenta ranging from about 5 to a few 100 GeV. A detailed description is given of the algorithms used to cluster energy in the electromagnetic calorimeter and to reconstruct electron trajectories in the tracker. The electron momentum is estimated by combining the energy measurement in the calorimeter with the momentum measurement in the tracker. Benchmark selection criteria are presented, and their performances assessed using Z, SIC, and J/psi decays into e(+)+e(-) pairs. The spectra of the observables relevant to electron reconstruction and selection as well as their global efficiencies are well reproduced by Monte Carlo simulations. The momentum scale is calibrated with an uncertainty smaller than 0.3%. The momentum resolution for electrons produced in Z boson decays ranges from 1.7 to 4.5%, depending on electron pseudorapidity and energy loss through bremsstrahlung in the detector material.Article Citation - WoS: 25Citation - Scopus: 27Symmergent Gravity, Seesawic New Physics, and Their Experimental Signatures(Hindawi Publishing Corporation, 2019) Demir, Durmuş AliThe standard model of elementary particles (SM) suffers from various problems, such as power-law ultraviolet (UV) sensitivity, exclusion of general relativity (GR), and absence of a dark matter candidate. The LHC experiments, according to which the TeV domain appears to be empty of new particles, started sidelining TeV-scale SUSY and other known cures of the UV sensitivity. In search for a remedy, in this work, it is revealed that affine curvature can emerge in a way restoring gauge symmetries explicitly broken by the UV cutoff. This emergent curvature cures the UV sensitivity and incorporates GR as symmetry-restoring emergent gravity (symmergent gravity, in brief) if a new physics sector (NP) exists to generate the Planck scale and if SM+NP is Fermi-Bose balanced. This setup, carrying fingerprints of trans-Planckian SUSY, predicts that gravity is Einstein (no higher-curvature terms), cosmic/gamma rays can originate from heavy NP scalars, and the UV cutoff might take right value to suppress the cosmological constant (alleviating fine-tuning with SUSY). The NP does not have to couple to the SM. In fact, NP-SM coupling can take any value from zero to Lambda SM2/Lambda NP2 if the SM is not to jump from Lambda SM approximate to 500GeV to the NP scale Lambda NP. The zero coupling, certifying an undetectable NP, agrees with all the collider and dark matter bounds at present. The seesawic bound Lambda SM2/Lambda NP2, directly verifiable at colliders, implies that (i) dark matter must have a mass less than or similar to Lambda SM, (ii) Higgs-curvature coupling must be approximate to 1.3%, (iii) the SM RGEs must remain nearly as in the SM, and (iv) right-handed neutrinos must have a mass less than or similar to 1000TeV. These signatures serve as a concise testbed for symmergence.Article Citation - WoS: 23Citation - Scopus: 26Curvature-Restored Gauge Invariance and Ultraviolet Naturalness(Hindawi Publishing Corporation, 2016) Demir, Durmuş AliIt is shown that (aΛ2+b|H|2)R in a spacetime of curvature R is a natural ultraviolet (UV) completion of (aΛ4+bΛ2|H|2) in the flat-spacetime Standard Model (SM) with Higgs field H, UV scale Λ, and loop factors a and b. This curvature completion rests on the fact that Λ-mass gauge theory in flat spacetime turns, on the cut view R=4Λ2, into a massless gauge theory in curved spacetime. It provides a symmetry reason for curved spacetime, wherein gravity and matter are both low-energy effective phenomena. Gravity arises correctly if new physics exists with at least 63 more bosons than fermions, with no need to interact with the SM and with dark matter as a natural harbinger. It can source various cosmological, astrophysical, and collider phenomena depending on its spectrum and couplings to the SM.Article Citation - WoS: 111Citation - Scopus: 97Missing Transverse Energy Performance of the Cms Detector(IOP Publishing Ltd., 2011) Karapınar, Güler; Demir, Durmuş AliDuring 2010 the LHC delivered pp collisions with a centre-of-mass energy of 7 TeV. In this paper, the results of comprehensive studies of missing transverse energy as measured by the CMS detector are presented. The results cover the measurements of the scale and resolution for missing transverse energy, and the effects of multiple pp interactions within the same bunch crossings on the scale and resolution. Anomalous measurements of missing transverse energy are studied, and algorithms for their identification are described. The performance of several reconstruction algorithms for calculating missing transverse energy are compared. An algorithm, called missing-transverse-energy significance, which estimates the compatibility of the reconstructed missing transverse energy with zero, is described, and its performance is demonstrated. © 2011 CERN for the benefit of the CMS collaboration, published under license by IOP Publishing Ltd. SISSA.Article Citation - WoS: 519Citation - Scopus: 401Determination of Jet Energy Calibration and Transverse Momentum Resolution in Cms(IOP Publishing Ltd., 2011) Karapınar, Güler; Demir, Durmuş AliMeasurements of the jet energy calibration and transverse momentum resolution in CMS are presented, performed with a data sample collected in proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 36pb-1. The transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transverse momentum resolution. The results are presented for three different methods to reconstruct jets: a calorimeter-based approach, the "Jet-Plus-Track" approach, which improves the measurement of calorimeter jets by exploiting the associated tracks, and the "Particle Flow" approach, which attempts to reconstruct individually each particle in the event, prior to the jet clustering, based on information from all relevant subdetectors.Article Citation - WoS: 113Citation - Scopus: 92Performance of ?-Lepton Reconstruction and Identification in Cms(IOP Publishing Ltd., 2012) Demir, Durmuş Ali; Karapınar, GülerThe performance of τ-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at s = 7 TeV, corresponding to an integrated luminosity of 36 pb-1 collected with the CMS detector at the LHC. The τ leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using τ leptons produced in Z-boson decays. The τ-lepton misidentification rates for jets and electrons are determined. © 2012 CERN for the benefit of the CMS collaboration, published under license by IOP Publishing Ltd and SISSA.