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Articles 241 - 270 of 329

Full-Text Articles in Physics

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 …

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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 …

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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; …

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Hybrid Organic/Quantum Dot Photovoltaics, Timothy Paul Osedach Jan 2012

Hybrid Organic/Quantum Dot Photovoltaics, Timothy Paul Osedach

Link Foundation Energy Fellowship Reports

The aim of the work conducted during this tenure as a Link Foundation Energy Fellow was to investigate the fundamental excitonic and charge transport process that are relevant in nanostructured photovoltaics structures, and to demonstrate photovoltaics structures that incorporate novel nanostructured materials toward realizing high efficiency and low cost solar cells.

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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 …

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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 …

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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 …

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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 …

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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 …

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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. …

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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 …

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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 …

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Measurement Of The Inclusive Production Cross Sections For Forward Jets And For Dijet Events With One Forward And One Central Jet 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

Measurement Of The Inclusive Production Cross Sections For Forward Jets And For Dijet Events With One Forward And One Central Jet 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

The inclusive production cross sections for forward jets, as well for jets in dijet events with at least one jet emitted at central and the other at forward pseudorapidities, are measured in the range of transverse momenta pT = 35-150 GeV/c in proton-proton collisions at √s =7 TeV by the CMS experiment at the LHC. Forward jets are measured within pseudorapidities 3.2 < |η| < 4.7, and central jets within the |η| < 2.8 range. The differential cross sections d2σ/dpT dη are compared to predictions from three approaches in perturbative quantum chromodynamics: (i) next-to-leading-order calculations obtained with and without matching to parton-shower Monte Carlo simulations, (ii) pythia and herwig parton-shower event generators with different tunes of parameters, and (iii) cascade and hej models, including different non-collinear corrections to standard single-parton radiation. The single-jet inclusive forward jet spectrum is well described by all models, but not all predictions are consistent with the spectra observed for the forward-central dijet events.

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Measurement Of The Cross Section For Production Of Bb̄X Decaying To Muons 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

Measurement Of The Cross Section For Production Of Bb̄X Decaying To Muons 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 inclusive cross section for the process pp → bb¯X → μμX′ at √s = 7 TeV is presented, based on a data sample corresponding to an integrated luminosity of 27.9 pb−1 collected by the CMS experiment at the LHC. By selecting pairs of muons each with pseudorapidity |η| < 2.1, the value σ(pp → bb¯X → μμX′) = 26.4 ± 0.1 (stat.) ±2.4 (syst.) ±1.1 (lumi.) nb is obtained for muons with transverse momentum pT > 4 GeV, and 5.12 ± 0.03 (stat.) ± 0.48 (syst.) ± 0.20 (lumi.) nb for pT > 6 GeV. These results are compared to QCD predictions at leading and next-to-leading orders.

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Search For Quark Compositeness In Dijet Angular Distributions From Pp Collisions At √S = 7 Tev, S. Chatrchyan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, The Cms Collaboration Jan 2012

Search For Quark Compositeness In Dijet Angular Distributions From 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 search for quark compositeness using dijet angular distributions from pp collisions at √s = 7 TeV is presented. The search has been carried out using a data sample corresponding to an integrated luminosity of 2.2 fb−1, recorded by the CMS experiment at the LHC. Normalized dijet angular distributions have been measured for dijet invariant masses from 0.4 TeV to above 3 TeV and compared with a variety of contact interaction models, including those which take into account the effects of next-to-leading-order QCD corrections. The data are found to be in agreement with the predictions of perturbative QCD, and lower …

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Search For Resonant T̄T Production In 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 2012

Search For Resonant T̄T Production In 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

A model-independent search for the production of heavy resonances decaying into top-antitop quark pairs is presented. The search is based on events containing one lepton (muon or electron) and at least two jets selected from data samples corresponding to an integrated luminosity of 4.4-5.0 fb−1 collected in pp collisions at √s = 7 TeV. Results are presented from the combination of two dedicated searches optimized for boosted production and production at threshold. No excess of events is observed over the expected yield from the standard model processes. Topcolor Z′ bosons with narrow (wide) width are excluded at 95% confidence level …

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Jet Production Rates In Association With W And Z Bosons 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

Jet Production Rates In Association With W And Z Bosons 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

Measurements of jet production rates in association with W and Z bosons for jet transverse momenta above 30 GeV are reported, using a sample of proton-proton collision events recorded by CMS at √s = 7TeV , corresponding to an integrated luminosity of 36 pb − 1. The study includes the measurement of the normalized inclusive rates of jets σ(V + ≥ n jets)/σ(V), where V represents either a W or a Z. In addition, the ratio of W to Z cross sections and the W charge asymmetry as a function of the number of associated jets are measured. A test …

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Inclusive B-Jet Production In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand Jan 2012

Inclusive B-Jet Production In Pp Collisions At S√=7tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand

Aerospace, Physics, and Space Science Faculty Publications

The inclusive b-jet production cross section in pp collisions at a center-of mass energy of 7 TeV is measured using data collected by the CMS experiment at the LHC. The cross section is presented as a function of the jet transverse momentum in the range 18 < p T  < 200 GeV for several rapidity intervals. The results are also given as the ratio of the b-jet production cross section to the inclusive jet production cross section. The measurement is performed with two different analyses, which differ in their trigger selection and b-jet identification: a jet analysis that selects events with a b …

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Search For The Standard Model Higgs Boson In The H → Zz → ℓ+ℓ−Τ+Τ− Decay Channel 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 The Standard Model Higgs Boson In The H → Zz → ℓ+ℓ−Τ+Τ− Decay Channel 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 is reported for the standard model Higgs boson in the H → ZZ → ℓ+ℓ−τ +τ − decay mode, where ℓ = μ or e, in proton-proton 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�=7TeV, corresponding to an integrated luminosity of 4.7 fb−1 collected with the CMS detector at the LHC. No evidence is found for a significant deviation from the background expectation. …

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Search For Third-Generation Leptoquarks And Scalar Bottom Quarks In Pp Collisions At P S = 7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, Francisco X. Yumiceva Jan 2012

Search For Third-Generation Leptoquarks And Scalar Bottom Quarks In Pp Collisions At P S = 7 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov, Francisco X. Yumiceva

Aerospace, Physics, and Space Science Faculty Publications

Results are presented from a search for third-generation leptoquarks and scalar bottom quarks in a sample of proton-proton 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��� collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.7 fb−1. A scenario where the new particles are pair produced and each decays to a b quark plus a tau neutrino or neutralino is considered. The number of …

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Measurement Of Jet Fragmentation Into Charged Particles In Pp And Pbpb Collisions At √Snn=2.76 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Measurement Of Jet Fragmentation Into Charged Particles In Pp And Pbpb Collisions At √Snn=2.76 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

Jet fragmentation in pp and PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair was studied using data collected with the CMS detector at the LHC. Fragmentation functions are constructed using charged-particle tracks with transverse momenta p T > 4 GeV/c for dijet events with a leading jet of p T > 100 GeV/c. The fragmentation functions in PbPb events are compared to those in pp data as a function of collision centrality, as well as dijet-p T imbalance. Special emphasis is placed on the most central PbPb events including dijets with unbalanced momentum, indicative …

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Suppression Of Non-Prompt J/Ψ, Prompt J/Ψ, And Υ (1s) In Pbpb Collisions At Snn−−−√=2.76 Tev, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor Vodopiyanov Jan 2012

Suppression Of Non-Prompt J/Ψ, Prompt J/Ψ, And Υ (1s) In Pbpb Collisions At Snn−−−√=2.76 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

Yields of prompt and non-prompt J/ψ, as well as Υ" 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;">ΥΥ(1S) mesons, are measured by the CMS experiment via their μ + μ − decays in PbPb and pp collisions at sNN=2.76" 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;" …

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Search For B0s → Μ + Μ − And B0 → Μ + Μ − Decays, The Cms Collaboration, S. Chatrchyan, V. Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov Jan 2012

Search For B0s → Μ + Μ − And B0 → Μ + Μ − Decays, 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

A search for the rare decays B0s → μ+μ− and B0 → μ+μ− is performed in pp collisions at √s = 7 TeV, with a data sample corresponding to an integrated luminosity of 5 fb−1 collected by the CMS experiment at the LHC. In both decays, the number of events observed after all selection requirements is consistent with the expectation from background plus standard model signal predictions. The resulting upper limits on the branching fractions are B(B0s→μ+μ−)<7.7×10−9 and B(B0→μ+μ−)<1.8×10−9 at 95% confidence level.

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Search For Leptonic Decays Of W′ Bosons 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

Search For Leptonic Decays Of W′ Bosons 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 a new heavy gauge boson W′ decaying to an electron or muon, plus a low mass neutrino, is presented. This study uses data corresponding to an integrated luminosity of 5.0 fb−1, collected using the CMS detector in pp collisions at a centre-of-mass energy of 7 TeV at the LHC. Events containing a single electron or muon and missing transverse momentum are analyzed. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the lepton-neutrino system, and upper limits for cross sections above different transverse mass thresholds …

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Exclusive Γγ → Μ + Μ − Production In Proton-Proton 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

Exclusive Γγ → Μ + Μ − Production In Proton-Proton 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 measurement of the exclusive two-photon production of muon pairs 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, pp → pμ + μ −p, is reported using data corresponding to an integrated luminosity of 40 pb−1. For muon pairs with invariant mass greater than 11.5 GeV, transverse momentum p T (μ) > 4 GeV and pseudorapidity |η(μ)| …

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Search For New Physics In Events With Same-Sign Dileptons And B-Tagged Jets In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, Vardan Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov Jan 2012

Search For New Physics In Events With Same-Sign Dileptons And B-Tagged Jets In Pp Collisions At S√=7 Tev, The Cms Collaboration, S. Chatrchyan, Vardan Khachatryan, Marc M. Baarmand, B. Dorney, Marcus Hohlmann, Himali Kalakhety, Igor B. Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

A search for new physics is performed using isolated same-sign dileptons with at least two b-quark jets in the final state. Results are based on a 4.98 fb−1 sample of proton-proton collisions at a centre-of-mass energy of 7 TeV collected by the CMS detector. No excess above the standard model background is observed. Upper limits at 95% confidence level are set on the number of events from non-standard-model sources. These limits are used to set constraints on a number of new physics models. Information on acceptance and efficiencies are also provided so that the results can be used to …

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Search For Dark Matter And Large Extra Dimensions In Monojet Events 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

Search For Dark Matter And Large Extra Dimensions In Monojet Events 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 has been made for events containing an energetic jet and an imbalance in transverse momentum using a data sample of pp collisions at a center-of-mass energy of 7 TeV. This signature is common to both dark matter and extra dimensions models. The data were collected by the CMS detector at the LHC and correspond to an integrated luminosity of 5.0 fb−1. The number of observed events is consistent with the standard model expectation. Constraints on the dark matter-nucleon scattering cross sections are determined for both spin-independent and spin-dependent interaction models. For the spin-independent model, these are …

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Search For Stopped Long-Lived Particles Produced 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 Jan 2012

Search For Stopped Long-Lived Particles Produced 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

A search has been performed for long-lived particles that have stopped in the CMS detector, during 7 TeV proton-proton operations of the CERN LHC. The existence of such particles could be inferred from observation of their decays when there were no proton-proton collisions in the CMS detector, namely during gaps between LHC beam crossings. Using a data set in which CMS recorded an integrated luminosity of 4.0 fb−1, and a search interval corresponding to 246 hours of trigger live time, 12 events are observed, with a mean background prediction of 8.6 ± 2.4 events. Limits are presented at …

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Measurement Of The B0 Production Cross Section In Pp Collisions At √S= 7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, B. Dorney, S. Guragain, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov Jun 2011

Measurement Of The B0 Production Cross Section In Pp Collisions At √S= 7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, B. Dorney, S. Guragain, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov

Aerospace, Physics, and Space Science Faculty Publications

Measurements of the differential production cross sections d =dpB T and d =dyB for B0 mesons produced in pp collisions at ffiffi s p ¼ 7 TeV are presented. The data set used was collected by the CMS experiment at the LHC and corresponds to an integrated luminosity of 40 pb 1. The production cross section is measured from B0 meson decays reconstructed in the exclusive final state J=c K0 S, with the subsequent decays J=c ! þ and K0 S ! þ . The total cross section for pB T > 5 GeV and jyBj < 2:2 is measured to be 33:2 2:5 3:5 b, where the first uncertainty is statistical and the second is systematic.

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Search For Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying To Tau Pairs In Pp Collisions At √S = 7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain Jun 2011

Search For Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying To Tau Pairs In Pp Collisions At √S = 7 Tev, S. A. Chatrchyan, V. Khachatryan, A. M. Sirunyan, Marc M. Baarmand, Marcus Hohlmann, H Kalakhety, Robert M. Ralich, Igor Vodopiyanov, B. Dorney, S. Guragain

Aerospace, Physics, and Space Science Faculty Publications

A search for neutral minimal supersymmetric standard model (MSSM) Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 pb 1 recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the …

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