Oktay Dogangun

Istanbul Bilgi University | BILGI · Department of Mecanical Engineering

A search is presented for a massive particle, generically referred to as a Z', decaying into a tt̄ pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze j...

Results are presented from a search for the production of a heavy gauge boson W' decaying into a top and a bottom quark, using a data set collected by the CMS experiment at sqrt(s)=8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. Various models of W'-boson production are studied by allowing for an arbitrary combinatio...

A measurement of total and fiducial inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=8 TeV is presented. Electron and muon final states are analyzed in a data sample collected with the CMS detector corresponding to an integrated luminosity of 18.2 +/- 0.5 inverse picobarns. The measured total inclusive cross sections ti...

The first observation of the associated production of a single top quark and a W boson is presented. The analysis is based on a data set corresponding to an integrated luminosity of 12.2 inverse femtobarns of proton-proton collisions at sqrt(s) = 8 TeV recorded by the CMS experiment at the LHC. Events with two leptons and a jet originating from a b...

A search for flavor-changing neutral currents in top-quark decays t to Zq is performed in events produced from the decay chain t t-bar to Zq+Wb, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A dataset collected with the CMS detector at the LHC is used, corresponding to an integrated lu...

The production of jets associated to bottom quarks is measured for the first time in PbPb collisions at a center-of-mass energy of 2.76 TeV per nucleon pair. Jet spectra are reported in the transverse momentum (pt) range of 80-250 GeV, and within pseudorapidity abs(eta < 2). The nuclear modification factor (R[AA]) calculated from these spectra show...

A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 inverse femtobarns and was collected at sqrt(s) = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected backgr...

Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at sqrt(s[NN]) = 2.76 TeV by the CMS collaboration, using data from the 2011 LHC heavy-ion run. The data set includes a sample of ultra-central (0-0.2% centrality) PbPb events collected using a trigger based on total transverse energy in the hadron forward ca...

Spin correlations in the t-tbar quark system and the polarization of the top quark are measured using dilepton final states produced in pp collisions at the LHC at sqrt(s)=7 TeV. The data correspond to an integrated luminosity of 5.0 inverse femtobarns collected with the CMS detector. The measurements are performed using events with two oppositely...

A search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at sqrt(s)=8 TeV. The top-quark decay considered in this search results in one light lepton (muon or electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond...

A study of proton-proton collisions in which two b hadrons are produced in association with a Z boson is reported. The collisions were recorded at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC, for an integrated luminosity of 5.2 inverse femtobarns. The b hadrons are identified by means of displaced secondary vertices, without t...

The first measurement of jet shapes, defined as the fractional transverse momentum radial distribution, for inclusive jets produced in heavy-ion collisions is presented. Data samples of PbPb and pp collisions, corresponding to integrated luminosities of 150 inverse microbarns and 5.3 inverse picobarns respectively, were collected at a nucleon-nucle...

An overview of recent results on top quark properties and interactions is given, obtained using data collected with the CMS and ATLAS experiments during the years 2011 and 2012 at 7 TeV and 8 TeV centre-of-mass energies. Measurements of top quark pair production cross sections in several top quark final states are reported. Moreover, cross sections...

An inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb−1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, α T...

A measurement of the Z gamma to nu nu-bar gamma cross section in pp collisions at sqrt(s) = 7 TeV is presented, using data corresponding to an integrated luminosity of 5.0 inverse femtobarns collected with the CMS detector. This measurement is based on the observation of events with an imbalance of transverse energy in excess of 130 GeV and a singl...

The results of a search for the bottomonium counterpart, denoted as Xb, of the exotic charmonium state X(3872) is presented. The analysis is based on a sample of pp collisions at sqrt(s) = 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 20.7 inverse femtobarns. The search looks for the exclusive decay...

The sequential suppression of the individual Upsilon states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp datasets used in these proceedings correspond to integrated luminosities of 150/μb and 230/nb, respectively, collected by the CMS experiment at the LHC at 2.76 TeV in 2011. The relative suppressio...

An inclusive search is presented for new heavy particle pairs produced in sqrt[s]=7 TeV proton-proton collisions at the LHC using 4.7±0.1 fb^{-1} of integrated luminosity. The selected events are analyzed in the 2D razor space of M_{R}, an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the miss...

The W-boson helicity fractions in top-quark decays are measured with ttbar events in the lepton+jets final state, using proton-proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 5.0 inverse femtobarns. The measured fractions of longitu...

Measurements of several top-quark properties, obtained from the CMS data collected in 2011 and 2012 at centre-of-mass energies of 7 and 8 TeV are presented. The results include measurements of the top pair charge asymmetry, the W helicity in top quark decays and the search for anomalous couplings, the top quark charge, and of the ttbar spin correla...

The mass of the top quark is measured using a sample of ttbar candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at sqrt(s)=7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 inverse femtobarns. The mass is reconstructed for each event employin...

The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass, mtpole, or the strong coupling constant, alphaS....

The Compact Muon Solenoid (CMS) has measured the suppression of the bottomonium states Y(1S), Y(2S), and Y(3S) in PbPb collisions at sqrt(s_NN) = 2.76 TeV relative to pp collisions, scaled by the number of inelastic nucleon-nucleon collisions. CMS observed a stronger suppression for the weaker bound Y(2S) and Y(3S) states than for the ground state...

Due to a computational error, the bottom right plot in �figure 1 of the original paper was incorrect. The corrected �figure is shown here (the top central and the bottom left plots are unchanged). This error does not affect the conclusion of the paper.

A search for physics beyond the standard model is performed with events having one or more hadronically decaying τ leptons, highly energetic jets, and large transverse momentum imbalance. The data sample corresponds to an integrated luminosity of 4.98 fb(-1) of proton-proton collisions at [Formula: see text] collected with the CMS detector at the L...

Measurements of event shapes and azimuthal correlations are presented for events where a Z boson is produced in association with jets in proton-proton collisions. The data collected with the CMS detector at the CERN LHC at root s = 7 TeV correspond to an integrated luminosity of 5.0 fb(-1). The analysis provides a test of predictions from perturbat...

Results are reported from a search for the anomalous production of highly boosted Z bosons with large transverse momentum and decaying to . Such Z bosons may be produced in the decays of new heavy particles. The search uses pp collision data at , corresponding to an integrated luminosity of recorded with the CMS detector. The shape of the observed...

Electroweak W and Z boson measurements in PbPb collisions at nucleon-nucleon center of mass energy s=2.76TeV at the LHC using the CMS detector are presented. The W analysis is based on 2010 PbPb data corresponding to an integrated luminosity of 7.3μb-1 and also on 2011 pp data corresponding to an integrated luminosity of 231nb-1. The Z analysis is...

Jet shape measurements are important for many applications. When measured in pp collisions they can be used to constrain generator and showering settings. When measured in PbPb collisions they can be used to probe for distortions from interactions with the hot and dense medium. Fully unfolded jet shape measurements are presented and compared with g...

Results are reported from a search for new physics processes in events containing a single isolated high-transverse-momentum lepton (electron or muon), energetic jets, and large missing transverse momentum. The analysis is based on a 4.98 fb(-1) sample of proton-proton collisions at a center-of-mass energy of 7 TeV, obtained with the CMS detector a...

A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for t t-bar events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 inverse femtobarns collected by the CMS experiment in pp collisions at sqrt(s) = 7 TeV. The analysis is based on endpoint determinations in...

A search for the pair production of a heavy, narrow resonance decaying into two jets has been performed using events collected in sqrt[s]=7 TeV pp collisions with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 5.0 fb^{-1}. Events are selected with at least four jets and two dijet combinations with similar di...

The first measurement of vector-boson production associated with a top quark-antiquark pair in proton-proton collisions at √s=7 TeV is presented. The results are based on a data set corresponding to an integrated luminosity of 5.0 fb1, recorded by the CMS detector at the LHC in 2011. The measurement is performed in two independent channels through...

The underlying event activity in proton-proton collisions at forward pseudo-rapidity (−6.6 < η < −5.2) is studied with the CMS detector at the LHC, using a novel observable: the ratio of the forward energy density, dE/dη, for events with a charged-particle jet produced at central pseudorapidity (|η jet| < 2) to the forward energy density for inclus...

The top-quark pair production cross section in 7 TeV center-of-mass energy proton-proton collisions is measured using data collected by the CMS detector at the LHC. The measurement uses events with one jet identified as a hadronically decaying tau lepton and at least four additional energetic jets, at least one of which is identified as coming from...

A search for excited leptons is carried out with the CMS detector at the LHC, using 36pb−1 of pp collision data recorded at s=7TeV. The search is performed for associated production of a lepton and an oppositely charged excited lepton ⁎pp→ℓℓ⁎, followed by the decay ⁎ℓ⁎→ℓγ , resulting in the ℓℓγ final state, where ℓ=e,μ. No excess of events above t...

A measurement of the a production cross section in pp collisions at root s = 7 TeV is presented. The results are based on data corresponding to an integrated luminosity of 2.3 fb(-1) collected by the CMS detector at the LHC. Selected events are required to have one isolated, high transverse momentum electron or muon, large missing transverse energy...

Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a τ lepton and a b quark. The search is based on a data sample of pp collisions at sqrt[s]=7 TeV, which is coll...

The polarizations of the Υ(1S), Υ(2S), and Υ(3S) mesons are measured in proton-proton collisions at sqrt[s]=7 TeV, using a data sample of Υ(nS)→μ^{+}μ^{-} decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb^{-1}. The dimuon decay angular distributions are analyzed in three different polarization frames. The p...

A study is presented of the mass and spin-parity of the new boson recently observed at the LHC at a mass near 125 GeV. An integrated luminosity of 17.3 fb^{-1}, collected by the CMS experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, is used. The measured mass in the ZZ channel, where both Z bosons decay to e or μ pair...

The polarizations of the Υ(1S), Υ(2S), and Υ(3S) mesons are measured in proton-proton collisions at s=7 TeV, using a data sample of Υ(nS)→μ+μ− decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb−1. The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization par...

Many models of new physics, including versions of supersymmetry (SUSY), predict production of events with low missing transverse energy, electroweak gauge bosons, and many energetic final-state particles. The stealth SUSY model yields this signature while conserving R-parity by means of a new hidden sector in which SUSY is approximately conserved....

A measurement is presented of the t[bar over t] production cross section (σ[subscript t[bar over t]]) in proton-proton collisions at a centre-of-mass energy of 7 TeV, in the all-jet final state that contains at least six jets, two of which are tagged as originating from b quarks. The data correspond to an integrated luminosity of 3.54 fb[superscrip...

The results of a search for flavor changing neutral currents in top quark decays in events with a topology compatible with the decay chain are presented. The search is performed with a data sample corresponding to an integrated luminosity of of proton–proton collisions at a center-of-mass energy of 7 TeV, collected with the CMS detector at the LHC....

Results are presented from a search for a narrow, spin-2 resonance decaying into a pair of Z bosons, with one Z-boson decaying into leptons ( or ) and the other into jets. An example of such a resonance is the Kaluza–Klein graviton, , predicted in Randall–Sundrum models. The analysis is based on a 4.9 fb−1 sample of proton–proton collisions at a ce...

First measurements of the azimuthal anisotropy of neutral pions produced in Pb-Pb collisions at a center-of-mass energy of sqrt[s_{NN}]=2.76 TeV are presented. The amplitudes of the second Fourier component (v_{2}) of the π^{0} azimuthal distributions are extracted using an event-plane technique. The values of v_{2} are studied as a function of the...

Evidence is presented for the associated production of a single top quark and W boson in pp collisions at sqrt[s]=7 TeV with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 4.9 fb^{-1}. The measurement is performed using events with two leptons and a jet originated from a b quark. A multivariate analysis b...

Results from the first study of isolated-photon + jet correlations in relativistic heavy ion collisions are reported. The analysis uses data from PbPb collisions at a centre-of-mass energy of per nucleon pair corresponding to an integrated luminosity of recorded by the CMS experiment at the LHC. For events containing an isolated photon with transve...

A measurement of the forward-backward asymmetry (A(FB)) of Drell-Yan lepton pairs in pp collisions at root s = 7 TeV is presented. The data sample, collected with the CMS detector, corresponds to an integrated luminosity of 5 fb(-1). The asymmetry is measured as a function of dilepton mass and rapidity in the dielectron and dimuon channels. Combine...

Measurements of event shapes and azimuthal correlations are presented for events where a Z boson is produced in association with jets in proton–proton collisions. The data collected with the CMS detector at the CERN LHC at √s = 7 TeV correspond to an integrated luminosity of 5.0 fb−1. The analysis provides a test of predictions from perturbative QC...

The top-quark pair production cross section in 7 TeV center-of-mass energy proton-proton collisions is measured using data collected by the CMS detector at the LHC. The measurement uses events with one jet identified as a hadronically decaying τ lepton and at least four additional energetic jets, at least one of which is identified as coming from a...

The top-quark pair production cross section in 7 TeV center-of-mass energy proton-proton collisions is measured using data collected by the CMS detector at the LHC. The measurement uses events with one jet identified as a hadronically decaying τ lepton and at least four additional energetic jets, at least one of which is identified as coming from a...

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The anisotropy of the azimuthal distributions of charged particles produced in PbPb collisions with a nucleon-nucleon center-of-mass energy of 2.76 TeV is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the eve...

Results are reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the μμ final state. The new bosons may be produced either promptly or via a decay chain. The data set corresponds to an integrated luminosity of 5.3 fb of proton-proton collisions at s=7 TeV, recorded by the CMS exper...

Results are presented from a search for heavy, right-handed muon neutrinos, N_{μ}, and right-handed W_{R} bosons, which arise in the left-right symmetric extensions of the standard model. The analysis is based on a 5.0 fb^{-1} sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected by the CMS detector at the Large Hadron C...