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Full-Text Articles in Physics

Search For Microscopic Black Holes In Pp Collisions At √ S = 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva Jul 2013

Search For Microscopic Black Holes In Pp Collisions At √ S = 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A search for microscopic black holes and string balls is presented, based on a data sample of pp collisions at √s = 8 TeV recorded by the CMS experiment at the Large Hadron Collider and corresponding to an integrated luminosity of 12 fb−1. No excess of events with energetic multiparticle final states, typical of black hole production or of similar new physics processes, is observed. Given the agreement of the observations with the expected standard model background, which is dominated by QCD multijet production, 95% confidence level limits are set on the production of semiclassical or quantum black holes, or …


Measurement Of The Λ0/B Lifetime In Pp Collisions At √S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva Jul 2013

Measurement Of The Λ0/B Lifetime In Pp Collisions At √S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A measurement of the Λ0 lifetime using the decay Λ0 → J/ψΛ in proton- √ b b proton collisions at s = 7 TeV is presented. The data set, corresponding to an integrated luminosity of about 5 fb−1, was recorded with the CMS experiment at the Large Hadron Collider using triggers that selected dimuon events in the J/ψ mass region. The Λ0 lifetime is measured to be 1.503 ± 0.052 (stat.) ± 0.031 (syst.) ps.


Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At √S= 7 And 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva Jun 2013

Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At √S= 7 And 8 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 fb−1 at √s = 7 TeV, and up to 5.3 fb−1 at √s = 8 TeV. The results for five Higgs boson decay modes γγ, ZZ, WW, ττ , and bb, which show a combined local significance of 5 standard deviations near 125 GeV, are reviewed. A fit to the invariant mass of …


Searches For Long-Lived Charged Particles In Pp Collisions At S√ =7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva Jun 2013

Searches For Long-Lived Charged Particles In Pp Collisions At S√ =7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results of searches for heavy stable charged particles produced in pp collisions at s" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√� = 7 and 8 TeV are presented corresponding to an integrated luminosity of 5.0 fb−1 and 18.8 fb−1, respectively. Data collected with the CMS detector are used to study the momentum, energy deposition, and time-of-flight of signal candidates. Leptons with an electric charge between e/3 and 8e …


Search For The Standard Model Higgs Boson Produced In Association With A Top-Quark Pair In Pp Collisions At The Lhc, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva May 2013

Search For The Standard Model Higgs Boson Produced In Association With A Top-Quark Pair In Pp Collisions At The Lhc, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

search for the standard model Higgs boson produced in association with a top-quark pair is presented using data samples corresponding to an integrated luminosity of 5.0 fb−1 (5.1 fb−1) collected in pp collisions at the center-of-mass energy of 7 TeV (8 TeV). Events are considered where the top-quark pair decays to either one lepton+jets (tt → .eνqqlbb) or dileptons (tt → .e+ν.e−νbb), .e being an electron or a muon. The search is optimized for the decay mode H → bb. The largest background to the ttH signal is top-quark pair production with additional jets. Artificial neural networks are used to …


Studies Of Jet Mass In Dijet And W/Z + Jet Events, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov, F. Yumiceva May 2013

Studies Of Jet Mass In Dijet And W/Z + Jet Events, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Abstract: Invariant mass spectra for jets reconstructed using the anti-kT and Cambridge- Aachen algorithms are studied for different jet “grooming” techniques in data corresponding to an integrated luminosity of 5 fb−1, recorded with the CMS detector in proton-proton collisions at the LHC at a center-of-mass energy of 7 TeV. Leading-order QCD predictions for inclusive dijet and W/Z+jet production combined with parton-shower Monte Carlo models are found to agree overall with the data, and the agreement improves with the implementation of jet grooming methods used to distinguish merged jets of large transverse momentum from softer QCD gluon radiation.


Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At S√=7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva May 2013

Observation Of A New Boson With Mass Near 125 Gev In Pp Collisions At S√=7 And 8 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Francisco Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 fb−1 at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV, and up to 5.3 fb−1 at s=8" role="presentation" style="box-sizing: inherit; display: inline; line-height: …


Study Of The Underlying Event At Forward Rapidity In Pp Collisions At √ S= 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov, F. Yumiceva Apr 2013

Study Of The Underlying Event At Forward Rapidity In Pp Collisions At √ S= 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

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 (|ηjet| < 2) to the forward energy density for inclusive events. This forward energy density ratio is measured as a function of the cen- tral jet transverse momentum, pT, at three different pp centre-of-mass energies (√s = 0.9, 2.76, and 7 TeV). In addition, the √s evolution of the forward energy density is studied in inclusive events and in events with a central jet. The results are compared to those of Monte Carlo event generators for pp collisions and are discussed in terms of the underly- ing event. Whereas the dependence of the forward energy density ratio on jet pT at each √s separately can be well reproduced by some models, all models fail to simultaneously describe the increase of the forward energy density with √s in both inclusive events and in events with a central jet.


Search For New Physics In Events With Photons, Jets, And Missing Transverse Energy In Pp Collisions At √S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov Mar 2013

Search For New Physics In Events With Photons, Jets, And Missing Transverse Energy In Pp Collisions At √S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov

Aerospace, Physics, and Space Science Faculty Publications

A search for physics beyond the standard model involving events with one or more photons, jets, and missing transverse energy has been performed by the CMS exper- iment. The data sample corresponds to an integrated luminosity of 4.93 fb−1 of proton- proton collisions at √s = 7 TeV, produced at the Large Hadron Collider. No excess of events with large missing transverse energy is observed beyond expectations from standard model processes, and upper limits on the signal production cross sections for new physics processes are set at the 95% confidence level. The results of this search are interpreted in the …


Search For Exotic Resonances Decaying Into Wz/Zz In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Feb 2013

Search For Exotic Resonances Decaying Into Wz/Zz In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data sample of pp collisions corresponding to an integrated luminosity of 5 fb−1 collected by the CMS experiment at the LHC at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; …


Search For Supersymmetry In Final States With Missing Transverse Energy And 0, 1, 2, Or ≥3 B-Quark Jets In 7 Tev Pp Collisions Using The Variable Αt, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov Jan 2013

Search For Supersymmetry In Final States With Missing Transverse Energy And 0, 1, 2, Or ≥3 B-Quark Jets In 7 Tev Pp Collisions Using The Variable Αt, The Cms Collaboration, M. M. Baarmand, B. Dorney, M. Hohlmann, H. Kalakhety, I. Vodopianov

Aerospace, Physics, and Space Science Faculty Publications

Abstract: A search for supersymmetry in final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of √s = 7 TeV. The data sample corresponds to an integrated luminosity of 4.98 fb−1 collected by the CMS exper- iment at the LHC. In this search, a dimensionless kinematic variable, αT, is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. The search is performed in a signal region that is binned in the scalar sum of the transverse energy of jets and the number of jets identified as originating …


Measurement Of The Hadronic Activity In Events With A Z And Two Jets And Extraction Of The Cross Section For The Electroweak Production Of A Z With Two Jets In Pp Collisions At Square Root Of S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva Jan 2013

Measurement Of The Hadronic Activity In Events With A Z And Two Jets And Extraction Of The Cross Section For The Electroweak Production Of A Z With Two Jets In Pp Collisions At Square Root Of S = 7 Tev, The Cms Collaboration, M. M. Baarmand, B Dorney, M. Hohlmann, H. Kalakhety, F. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Abstract: The first measurement of the electroweak production cross section of a Z boson with two jets (Zjj) in pp collisions at √s = 7 TeV is presented, based on a data sample recorded by the CMS experiment at the LHC with an integrated luminosity of 5 fb−1. The cross section is measured for the jj ( = e, µ) final state in the kinematic region mff > 50 GeV, mjj > 120 GeV, transverse momenta pj > 25 GeV and pseudorapidity |ηj| < 4.0. The measurement, combining the muon and electron channels, yields σ = 154 ± 24 (stat.) ± 46 (exp. syst.) ± 27 (th. syst.) ± 3 (lum.) fb, in agreement with the theoretical cross section. The hadronic activity, in the rapidity interval between the jets, is also measured. These results establish an important foundation for the more general study of vector boson fusion processes, of relevance for Higgs boson searches and for measurements of electroweak gauge couplings and vector boson scattering.


Search For Heavy Quarks Decaying Into A Top Quark And A W Or Z Boson Using Lepton + Jets Events In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration Jan 2013

Search For Heavy Quarks Decaying Into A Top Quark And A W Or Z Boson Using Lepton + Jets Events In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Results are presented from a search for the pair-production of heavy quarks, QQ¯ , that decay exclusively into a top quark and a W or Z boson. The search is performed using a sample of proton-proton collisions at √s = 7 TeV corresponding to an integrated luminosity of 5.0 fb−1, collected by the Compact Muon Solenoid experiment. The signal region is defined using a sample of events containing one electron or muon, missing transverse momentum, and at least four jets with large transverse momenta, where one jet is likely to originate from the decay of a bottom quark. No significant …


Search For New Physics With Long-Lived Particles Decaying To Photons And Missing Energy In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Nov 2012

Search For New Physics With Long-Lived Particles Decaying To Photons And Missing Energy In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search is performed for long-lived neutral particles decaying into a photon and invisible particles. An example of such a signature is the decay of the lightest neutralino with nonzero lifetime into a gravitino and a photon in gauge-mediated supersymmetry, with the neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest. The search uses events containing photons, missing transverse energy, and jets. The impact parameter of the photon relative to the beam-beam collision point can be reconstructed using converted photons. The method is sensitive to lifetimes of the order of 0.1 to 1 ns. The data sample …


Search For Electroweak Production Of Charginos And Neutralinos Using Leptonic Final States In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov Nov 2012

Search For Electroweak Production Of Charginos And Neutralinos Using Leptonic Final States In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

The 2011 dataset of the CMS experiment, consisting of an integrated luminosity of 4.98 fb−1 of pp collisions at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV, enables expanded searches for direct electroweak pair production of charginos and neutralinos in supersymmetric models as well as their analogs in other models of new physics. Searches sensitive to such processes, with decays to final states that contain two or more leptons, are presented. …


Search For A Fermiophobic Higgs Boson In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Sep 2012

Search For A Fermiophobic Higgs Boson In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

Combined results are reported from searches for a fermiophobic Higgs boson in the γγ, WW, and ZZ decay modes in proton-proton collisions at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV. The explored Higgs boson mass range is 110–300 GeV. The data sample corresponds to an integrated luminosity of 4.9–5.1 fb−1. A fermiophobic Higgs boson is excluded at 95% confidence level in the mass range 110–194 GeV, and at 99% …


Measurement Of The Underlying Event Activity In Pp Collisions At S√=0.9 And 7 Tev With The Novel Jet-Area/Median Approach, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Aug 2012

Measurement Of The Underlying Event Activity In Pp Collisions At S√=0.9 And 7 Tev With The Novel Jet-Area/Median Approach, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

The first measurement of the charged component of the underlying event using the novel “jet-area/median” approach is presented for proton-proton collisions at centre-of-mass energies of 0.9 and 7 TeV. The data were recorded in 2010 with the CMS experiment at the LHC. A new observable, sensitive to soft particle production, is introduced and investigated inclusively and as a function of the event scale defined by the transverse momentum of the leading jet. Various phenomenological models are compared to data, with and without corrections for detector effects. None of the examined models describe the data satisfactorily.


Search For A Light Charged Higgs Boson In Top Quark Decays In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov Jul 2012

Search For A Light Charged Higgs Boson In Top Quark Decays In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

Results are presented on a search for a light charged Higgs boson that can be produced in the decay of the top quark t → H+b and which, in turn, decays into τ +ν τ . The analysed data correspond to an integrated luminosity of about 2 fb−1 recorded in protonproton collisions at s=7TeV" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7TeV�=7��� by the CMS experiment at the LHC. The …


Search For Anomalous Production Of Multilepton Events In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jun 2012

Search For Anomalous Production Of Multilepton Events In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search for anomalous production of events with three or more isolated leptons in pp collisions at s=7TeV" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7TeV�=7��� is presented. The data, corresponding to an integrated luminosity of 4.98 fb−1, were collected by the CMS experiment at the LHC during the 2011 run. The search is applicable to any model of new physics that enhances multiple lepton production. The observed multilepton events are categorized …


Measurement Of The Z/Γ* + B-Jet Cross Section In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jun 2012

Measurement Of The Z/Γ* + B-Jet Cross Section In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

The production of b jets in association with a Z/γ* boson is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV and recorded by the CMS detector. The inclusive cross section for Z/γ* + b-jet production is measured in a sample corresponding to an integrated luminosity of 2.2 fb−1. The Z/γ* + b-jet cross section with Z/γ* → ℓℓ (where ℓℓ = ee or μμ) for events with the invariant mass 60 < M ℓℓ  < 120 GeV, at least one b jet at the hadron level with p T > 25 GeV and |η| < 2.1, and a separation between the leptons and the jets of ΔR > 0.5 is found to …


Shape, Transverse Size, And Charged-Hadron Multiplicity Of Jets In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jun 2012

Shape, Transverse Size, And Charged-Hadron Multiplicity Of Jets In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

Measurements of jet characteristics from inclusive jet production in protonproton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 pb−1. The mean charged-hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-k T algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo …


Search For Heavy Bottom-Like Quarks In 4.9 Fb−1 Of Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov May 2012

Search For Heavy Bottom-Like Quarks In 4.9 Fb−1 Of Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

Results are presented from a search for heavy bottom-like quarks, pair-produced in pp collisions at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV, undertaken with the CMS experiment at the LHC. The b′ quarks are assumed to decay exclusively to tW. The b′b¯′→tW−t¯W+" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; …


J/Ψ And Ψ (2s) Production In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration Jan 2012

J/Ψ And Ψ (2s) Production In Pp Collisions At √S = 7 Tev, S. Chatrchyan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A measurement of the J/ψ and ψ(2S) production cross sections in pp collisions at √s = 7TeV with the CMS experiment at the LHC is presented. The data sample corresponds to an integrated luminosity of 37 pb−1. Using a fit to the invariant mass and decay length distributions, production cross sections have been measured separately for prompt and non-prompt charmonium states, as a function of the meson transverse momentum in several rapidity ranges and integrated in the kinematical regions considered in this study. In addition, cross sections restricted to the acceptance of the CMS detector are given, which are not …


Measurement Of The Top-Quark Mass In Tt¯ Events With Lepton+Jets Final States In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Measurement Of The Top-Quark Mass In Tt¯ Events With Lepton+Jets Final States In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

The mass of the top quark is measured using a sample of tt candidate events with one electron or muon and at least four jets in the nal state, collected by CMS in pp collisions at p s = 7TeV at the LHC. A total of 5174 candidate events is selected from data corresponding to an integrated luminosity of 5.0 fb􀀀1. For each event the mass is reconstructed from a kinematic t of the decay products to a tt hypothesis. The topquark mass is determined simultaneously with the jet energy scale (JES), constrained by the known mass of the W …


Search For Microscopic Black Holes In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Search For Microscopic Black Holes In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search for microscopic black holes in pp collisions at a center-of-mass energy of 7 TeV is presented. The data sample corresponds to an integrated luminosity of 4.7 fb−1 recorded by the CMS experiment at the LHC in 2011. Events with large total transverse energy have been analyzed for the presence of multiple energetic jets, leptons, and photons, which are typical signals of evaporating semiclassical and quantum black holes, and string balls. Agreement with the expected standard model backgrounds, which are dominated by QCD multijet production, has been observed for various combined multiplicities of jets and other reconstructed objects …


Observation Of Z Decays To Four Leptons With The Cms Detector At The Lhc, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Observation Of Z Decays To Four Leptons With The Cms Detector At The Lhc, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

he first observation of the Z boson decaying to four leptons in proton-proton collisions is presented. The analyzed data set corresponds to an integrated luminosity of 5.02 fb−1 at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV collected by the CMS detector at the Large Hadron Collider. A pronounced resonance peak, with a statistical significance of 9.7 σ, is observed in the distribution of the invariant mass of four leptons …


Measurement Of The Single-Top-Quark T-Channel Cross Section In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov, Francisco Yumiceva Jan 2012

Measurement Of The Single-Top-Quark T-Channel Cross Section In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov, Francisco Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

A measurement of the single-top-quark t-channel production cross section in pp collisions at s=7" role="presentation" style="box-sizing: inherit; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">s√=7�=7 TeV with the CMS detector at the LHC is presented. Two different and complementary approaches have been followed. The first approach exploits the distributions of the pseudorapidity of the recoil jet and reconstructed top-quark mass using background estimates determined from control samples in data. The second approach is based on multivariate …


Search For Supersymmetry In Hadronic Final States Using Mt2 In Pp Collisions At √S = 7 Tev, The Cms Collaboration, S. Chatrchyan, Vardan Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Search For Supersymmetry In Hadronic Final States Using Mt2 In Pp Collisions At √S = 7 Tev, The Cms Collaboration, S. Chatrchyan, Vardan Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search for supersymmetry or other new physics resulting in similar final states is presented using a data sample of 4.73 fb−1 of pp collisions collected at √s = 7 TeV with the CMS detector at the LHC. Fully hadronic final states are selected based on the variable MT2, an extension of the transverse mass in events with two invisible particles. Two complementary studies are performed. The first targets the region of parameter space with medium to high squark and gluino masses, in which the signal can be separated from the standard model backgrounds by a tight requirement on MT2. …


Search For A Higgs Boson In The Decay Channel H → Zz* → Qqℓ-ℓ-+ In Pp Collisions At P√S = 7tev, S. Chatrchyans, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration Jan 2012

Search For A Higgs Boson In The Decay Channel H → Zz* → Qqℓ-ℓ-+ In Pp Collisions At P√S = 7tev, S. Chatrchyans, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for the standard model Higgs boson decaying into two Z bosons with subsequent decay into a final state containing two quark jets and two leptons, H → ZZ(*) → q q¯ ℓ−ℓ+ is presented. Results are based on data corresponding to an integrated luminosity of 4.6 fb−1 of proton-proton collisions at √s = 7 TeV, collected with the CMS detector at the LHC. In order to discriminate between signal and background events, kinematic and topological quantities, including the angular spin correlations of the decay products, are employed. Events are further classified according to the probability of the jets …


Measurement Of The Mass Difference Between Top And Antitop Quarks, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Measurement Of The Mass Difference Between Top And Antitop Quarks, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A measurement of the mass difference between the top and the antitop quark (Delta m(t) = m(t) - m(anti-t)) is performed using events with a muon or an electron and at least four jets in the final state. The analysis is based on data collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.96 +/- 0.11 inverse femtobarns, and yields the value of Delta m(t) = -0.44 +/- 0.46 (stat) +/- 0.27 (syst) GeV. This result is consistent with equality of particle and antiparticle masses required by CPT invariance, and provides a significantly improved precision …