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2016

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Articles 10351 - 10380 of 10866

Full-Text Articles in Physical Sciences and Mathematics

Search For W' Decaying To Tau Lepton And Neutrino In Proton-Proton Collisions At S=8 Tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For W' Decaying To Tau Lepton And Neutrino In Proton-Proton Collisions At S=8 Tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The first search for a heavy charged vector boson in the final state with a tau lepton and a neutrino is reported, using 19.7 fb-1 of LHC data at s=8 TeV. A signal would appear as an excess of events with high transverse mass, where the standard model background is low. No excess is observed. Limits are set on a model in which the W' decays preferentially to fermions of the third generation. These results substantially extend previous constraints on this model. Masses below 2.0 to 2.7 TeV are excluded, depending on the model parameters. In addition, the existence of …

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A Search For Pair Production Of New Light Bosons Decaying Into Muons, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

A Search For Pair Production Of New Light Bosons Decaying Into Muons, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7 fb-1 collected in proton-proton collisions at center-of-mass energy of √s=8 TeV. No excess is observed in the data relative to standard model background expectation and a model independent upper limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context of the next-to-minimal supersymmetric standard model, and …

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Search For Supersymmetry In Events With A Photon, A Lepton, And Missing Transverse Momentum In Pp Collisions At √S=8tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Supersymmetry In Events With A Photon, A Lepton, And Missing Transverse Momentum In Pp Collisions At √S=8tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for supersymmetry involving events with at least one photon, one electron or muon, and large missing transverse momentum has been performed by the CMS experiment. The data sample corresponds to an integrated luminosity of 19.7 fb-1 of pp collisions at s=8 TeV, produced at the CERN LHC. No excess of events is observed beyond expectations from standard model processes. The result of the search is interpreted in the context of a general model of gauge-mediated supersymmetry breaking, where the charged and neutral winos are the next-to-lightest supersymmetric particles. Within this model, winos with a mass up to 360 …

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Search For Neutral Mssm Higgs Bosons Decaying To Μ+Μ− In Pp Collisions At √S=7and8tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Neutral Mssm Higgs Bosons Decaying To Μ+Μ− In Pp Collisions At √S=7and8tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for neutral Higgs bosons predicted in the minimal supersymmetric standard model (MSSM) for μ+μ- decay channels is presented. The analysis uses data collected by the CMS experiment at the LHC in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.3 fb-1, respectively. The search is sensitive to Higgs bosons produced either through the gluon fusion process or in association with a bb quark pair. No statistically significant excess is observed in the μ+μ- mass spectrum. Results are interpreted in the framework of several benchmark scenarios, and the data are …

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Search For Exotic Decays Of A Higgs Boson Into Undetectable Particles And One Or More Photons, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Exotic Decays Of A Higgs Boson Into Undetectable Particles And One Or More Photons, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for exotic decays of a Higgs boson into undetectable particles and one or two isolated photons in pp collisions at a center-of-mass energy of 8TeV. The data correspond to an inte-grated luminosity of up to 19.4fb−1collected with the CMS detector at the LHC. Higgs bosons produced in gluon–gluon fusion and in association with a Z boson are investigated, using models in which the Higgs boson decays into a gravitino and a neutralino or a pair of neutralinos, followed by the decay of the neutralino to a gravitino and a photon. The selected events are consistent with …

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Observation Of Top Quark Pairs Produced In Association With A Vector Boson In Pp Collisions At √S = 8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Observation Of Top Quark Pairs Produced In Association With A Vector Boson In Pp Collisions At √S = 8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb-1, collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from tt̄W or tt̄Z decays. The tt̄W cross section is measured to be (Formula Presented) …

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Measurement Of The W Boson Helicity Fractions In The Decays Of Top Quark Pairs To Lepton + Jets Final States Produced In Pp Collisions At S=8tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Measurement Of The W Boson Helicity Fractions In The Decays Of Top Quark Pairs To Lepton + Jets Final States Produced In Pp Collisions At S=8tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The W boson helicity fractions from top quark decays in tt‾ events are measured using data from proton–proton collisions at a centre-of-mass energy of 8TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8fb−1. Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F0=0.681±0.012(stat)±0.023(syst), FL=0.323±0.008(stat)±0.014(syst), and FR=−0.004±0.005(stat)±0.014(syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. …

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ϒ(Ns) Polarizations Versus Particle Multiplicity In Pp Collisions At S=7 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

ϒ(Ns) Polarizations Versus Particle Multiplicity In Pp Collisions At S=7 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The polarizations of the ϒ(1S), ϒ(2S), and ϒ(3S) mesons are measured as a function of the charged particle multiplicity in proton–proton collisions at s=7 TeV. The measurements are performed with a dimuon data sample collected in 2011 by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb−1. The results are extracted from the dimuon decay angular distributions, in two ranges of ϒ(nS) transverse momentum (10–15 and 15–35 GeV), and in the rapidity interval |y|>1.2. The results do not show significant changes from low- to high-multiplicity pp collisions, although large uncertainties preclude definite statements in the ϒ(2S) and …

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Search For Lepton Flavour Violating Decays Of The Higgs Boson To Eτ And Eμ In Proton–Proton Collisions At S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Lepton Flavour Violating Decays Of The Higgs Boson To Eτ And Eμ In Proton–Proton Collisions At S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A direct search for lepton flavour violating decays of the Higgs boson (H) in the H→eτ and H→eμ channels is described. The data sample used in the search was collected in proton–proton collisions at s=8 TeV with the CMS detector at the LHC and corresponds to an integrated luminosity of 19.7 fb−1. No evidence is found for lepton flavour violating decays in either final state. Upper limits on the branching fractions, B(H→eτ)<0.69% and B(H→eμ)<0.035%, are set at the 95% confidence level. The constraint set on B(H→eτ) is an order of magnitude more stringent than the existing indirect limits. The limits are used to constrain the corresponding flavour violating Yukawa couplings, absent in the standard model.

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Combined Search For Anomalous Pseudoscalar Hvv Couplings In Vh(H→Bb‾) Production And H → Vv Decay, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Combined Search For Anomalous Pseudoscalar Hvv Couplings In Vh(H→Bb‾) Production And H → Vv Decay, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (=W or Z) in a sample of proton–proton collision events corresponding to an integrated luminosity of 18.9 fb−1 at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions fa3, is assessed by means of profile likelihood …

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Study Of Z Boson Production In Ppb Collisions At √Snn=5.02 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Study Of Z Boson Production In Ppb Collisions At √Snn=5.02 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The production of Z bosons in pPb collisions at sNN=5.02 TeV is studied by the CMS experiment via the electron and muon decay channels. The inclusive cross section is compared to pp collision predictions, and found to scale with the number of elementary nucleon-nucleon collisions. The differential cross sections as a function of the Z boson rapidity and transverse momentum are measured. Though they are found to be consistent within uncertainty with theoretical predictions both with and without nuclear effects, the forward-backward asymmetry suggests the presence of nuclear effects at large rapidities. These results provide new data for constraining nuclear …

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Search For Neutral Resonances Decaying Into A Z Boson And A Pair Of B Jets Or Τ Leptons, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Neutral Resonances Decaying Into A Z Boson And A Pair Of B Jets Or Τ Leptons, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is performed for a new resonance decaying into a lighter resonance and a Z boson. Two channels are studied, targeting the decay of the lighter resonance into either a pair of oppositely charged τ leptons or a bb pair. The Z boson is identified via its decays to electrons or muons. The search exploits data collected by the CMS experiment at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.8 fb-1. No significant deviations are observed from the standard model expectation and limits are set on production cross sections and parameters of two-Higgs-doublet models.

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Measurement Of Spin Correlations In Tt Production Using The Matrix Element Method In The Muon+Jets Final State In Pp Collisions At √S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Measurement Of Spin Correlations In Tt Production Using The Matrix Element Method In The Muon+Jets Final State In Pp Collisions At √S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The consistency of the spin correlation strength in top quark pair production with the standard model (SM) prediction is tested in the muon+jets final state. The events are selected from pp collisions, collected by the CMS detector, at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The data are compared with the expectation for the spin correlation predicted by the SM and with the expectation of no correlation. Using a template fit method, the fraction of events that show SM spin correlations is measured to be 0.72±0.08(stat)+0.15-0.13(syst), representing the most precise measurement of this …

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Measurement Of The Zγ→Νν‾Γ Production Cross Section In Pp Collisions At S=8 Tev And Limits On Anomalous Zzγ And Zγγ Trilinear Gauge Boson Couplings, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Measurement Of The Zγ→Νν‾Γ Production Cross Section In Pp Collisions At S=8 Tev And Limits On Anomalous Zzγ And Zγγ Trilinear Gauge Boson Couplings, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

An inclusive measurement of the Zγ→νν‾γ production cross section in pp collisions at s=8TeV is presented, using data corresponding to an integrated luminosity of 19.6 fb−1 collected with the CMS detector at the LHC. This measurement is based on the observation of events with large missing energy and with a single photon with transverse momentum above 145GeV and absolute pseudorapidity in the range |η|<1.44. The measured Zγ→νν‾γ production cross section, 52.7±2.1 (stat)±6.4 (syst)±1.4 (lumi) fb, agrees well with the standard model prediction of 50.0−2.2 +2.4 fb. A study of the photon transverse momentum spectrum yields the most stringent limits to date on the anomalous ZZγ and Zγγ trilinear gauge boson couplings.

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Measurement Of The Inelastic Cross Section In Proton–Lead Collisions At √Snn=5.02 Tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Measurement Of The Inelastic Cross Section In Proton–Lead Collisions At √Snn=5.02 Tev, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Mareskas-Palcek, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The inelastic hadronic cross section in proton–lead collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is measured with the CMS detector at the LHC. The data sample, corresponding to an integrated luminosity of L=12.6±0.4 nb−1, has been collected with an unbiased trigger for inclusive particle production. The cross section is obtained from the measured number of proton–lead collisions with hadronic activity produced in the pseudorapidity ranges 3<η<5 and/or −5<η<−3, corrected for photon-induced contributions, experimental acceptance, and other instrumental effects. The inelastic cross section is measured to be σinel(pPb)=2061±3(stat)±34(syst)±72(lumi) mb. Various Monte Carlo generators, commonly used in heavy ion and cosmic ray physics, are found to reproduce the data within uncertainties. The value of σinel(pPb) is compatible with that expected from the proton–proton cross section at 5.02 TeV scaled up within a simple Glauber approach to account for multiple scatterings in the lead nucleus, indicating that further net nuclear corrections are small.

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Search For A Low-Mass Pseudoscalar Higgs Boson Produced In Association With A Bb̅ Pair In Pp Collisions At √S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For A Low-Mass Pseudoscalar Higgs Boson Produced In Association With A Bb̅ Pair In Pp Collisions At √S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is reported for a light pseudoscalar Higgs boson decaying to a pair of τ leptons, produced in association with a bb pair, in the context of two-Higgs-doublet models. The results are based on pp collision data at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC and corresponding to an integrated luminosity of 19.7 fb-1. Pseudoscalar boson masses between 25 and 80 GeV are probed. No evidence for a pseudoscalar boson is found and upper limits are set on the product of cross section and branching fraction to τ pairs between 7 and …

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Search For R-Parity Violating Decays Of A Top Squark In Proton–Proton Collisions At S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For R-Parity Violating Decays Of A Top Squark In Proton–Proton Collisions At S=8 Tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The results of a search for a supersymmetric partner of the top quark (top squark), pair-produced in proton–proton collisions at s=8 TeV, are presented. The search, which focuses on R-parity violating, chargino-mediated decays of the top squark, is performed in final states with low missing transverse momentum, two oppositely charged electrons or muons, and at least five jets. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb−1 collected with the CMS detector at the LHC in 2012. The data are found to be in agreement with the standard model expectation, and upper limits are placed …

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Search For Supersymmetry In The Multijet And Missing Transverse Momentum Final State In Pp Collisions At 13tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration Jan 2016

Search For Supersymmetry In The Multijet And Missing Transverse Momentum Final State In Pp Collisions At 13tev, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for new physics is performed based on all-hadronic events with large missing transverse momentum produced in proton-proton collisions at s=13 TeV. The data sample, corresponding to an integrated luminosity of 2.3 fb-1, was collected with the CMS detector at the CERN LHC in 2015. The data are examined in search regions of jet multiplicity, tagged bottom quark jet multiplicity, missing transverse momentum, and the scalar sum of jet transverse momenta. The observed numbers of events in all search regions are found to be consistent with the expectations from standard model processes. Exclusion limits are presented for simplified supersymmetric …

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Evidence Of Magnetic Field Decay In Massive Main-Sequence Stars, Luca Fossati, Fabian R.N. Schneider, Norberto Castro, Norbert Langer, Sergio Simón-Díaz, André Luís Müller, Alex De Koter, Thierry Morel, Véronique Petit, Hugues Sana, Gregg A. Wade Jan 2016

Evidence Of Magnetic Field Decay In Massive Main-Sequence Stars, Luca Fossati, Fabian R.N. Schneider, Norberto Castro, Norbert Langer, Sergio Simón-Díaz, André Luís Müller, Alex De Koter, Thierry Morel, Véronique Petit, Hugues Sana, Gregg A. Wade

Aerospace, Physics, and Space Science Faculty Publications

A significant fraction of massive main-sequence stars show strong, large-scale magnetic fields. The origin of these fields, their lifetimes, and their role in shaping the characteristics and evolution of massive stars are currently not well understood. We compile a catalogue of 389 massive main-sequence stars, 61 of which are magnetic, and derive their fundamental parameters and ages. The two samples contain stars brighter than magnitude 9 in the V-band and range in mass between 5 and 100 M⊙. We find that the fractional main-sequence age distribution of all considered stars follows what is expected for a magnitude limited sample, while …

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The Puzzling Properties Of The Magnetic O Star Tr16-22, Yaël Nazé, Rodolfo Barbá, Stefano Bagnulo, Nidia Morrell, Roberto Gamen, Véronique Petit, Coralie Neiner Jan 2016

The Puzzling Properties Of The Magnetic O Star Tr16-22, Yaël Nazé, Rodolfo Barbá, Stefano Bagnulo, Nidia Morrell, Roberto Gamen, Véronique Petit, Coralie Neiner

Aerospace, Physics, and Space Science Faculty Publications

Context. The detection of bright, hard, and variable X-ray emission in Tr16-22 prompted spectropolarimetric observations of this star, which in turn led to the discovery of a surface magnetic field. Aims. We want to further constrain the properties of this star, in particular to verify whether X-ray variations are correlated to changes in optical emission lines and magnetic field strength, as expected from the oblique rotator model that is widely accepted for magnetic O stars. Methods. We have obtained new low-resolution spectropolarimetric and long-term high-resolution spectroscopic monitoring of Tr16-22, and we also analyse new, serendipitous X-ray data. Results. The new …

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A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, A U. Abeysekara, Jamie A. Holder Jan 2016

A Search For Brief Optical Flashes Associated With The Seti Target Kic 8462852, A U. Abeysekara, Jamie A. Holder

Aerospace, Physics, and Space Science Faculty Publications

The F-type star KIC 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC→8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon m-2, is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.

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Scaling Properties Of Fractional Momentum Loss Of High- Pt Hadrons In Nucleus-Nucleus Collisions At √Snn From 62.4 Gev To 2.76 Tev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki, Phenix Collaboration Jan 2016

Scaling Properties Of Fractional Momentum Loss Of High- Pt Hadrons In Nucleus-Nucleus Collisions At √Snn From 62.4 Gev To 2.76 Tev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Measurements of the fractional momentum loss (Sloss ≡ δpT/pT) of high-transverse-momentum-identified hadrons in heavy-ion collisions are presented. Using π⁰ in Au+Au and Cu+Cu collisions at √sNN=62.4 and 200 GeV measured by the PHENIX experiment at the Relativistic Heavy Ion Collider and and charged hadrons in Pb+Pb collisions measured by the ALICE experiment at the Large Hadron Collider, we studied the scaling properties of Sloss as a function of a number of variables: the number of participants, Npart, the number of quark participants, Nqp, the charged-particle density, dNch/dη, and the Bjorken energy density times the equilibration time, ᵋᵦjτ₀. We find that …

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Measurement Of Higher Cumulants Of Net-Charge Multiplicity Distributions In Au + Au Collisions At √Snn =7.7-200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, Phenix Collaboration Jan 2016

Measurement Of Higher Cumulants Of Net-Charge Multiplicity Distributions In Au + Au Collisions At √Snn =7.7-200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

We report the measurement of cumulants (Cn,n=1,...,4) of the net-charge distributions measured within pseudorapidity (|η|<0.35) in Au+Au collisions at √sNN=7.7-200GeV with the PHENIX experiment at the Relativistic Heavy Ion Collider. The ratios of cumulants (e.g., C₁/C₂, C₃/C₁) of the net-charge distributions, which can be related to volume independent susceptibility ratios, are studied as a function of centrality and energy. These quantities are important to understand the quantum-chromodynamics phase diagram and possible existence of a critical end point. The measured values are very well described by expectation from negative binomial distributions. We do not observe any nonmonotonic behavior in the ratios of the cumulants as a function of collision energy. The measured values of C₁/C₂ and C₃/C₁ can be directly compared to lattice quantum-chromodynamics calculations and thus allow extraction of both the chemical freeze-out temperature and the baryon chemical potential at each center-of-mass energy. The extracted baryon chemical potentials are in excellent agreement with a thermal-statistical analysis model.

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Transverse Energy Production And Charged-Particle Multiplicity At Midrapidity In Various Systems From √Snn =7.7 To 200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki Jan 2016

Transverse Energy Production And Charged-Particle Multiplicity At Midrapidity In Various Systems From √Snn =7.7 To 200 Gev, Andrew Marshall Adare, Gyöngyi Baksay, László A. Baksay, Klaus Dehmelt, Marcus Hohlmann, S. Rembeczki

Aerospace, Physics, and Space Science Faculty Publications

Measurements of midrapidity charged-particle multiplicity distributions, dNch/dη, and midrapidity transverse-energy distributions, dET/dη, are presented for a variety of collision systems and energies. Included are distributions for Au+Au collisions at sNN=200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu+Cu collisions at √sNN=200 and 62.4 GeV, Cu+Au collisions at √sNN=200 GeV, U+U collisions at √sNN=193 GeV, d+Au collisions at √sNN=200 GeV, ³He+Au collisions at √sNN=200 GeV, and p+p collisions at √sNN=200 GeV. Centrality-dependent distributions at midrapidity are presented in terms of the number of nucleon participants, Npart, and the number of constituent quark participants, Nqp. For all A+A collisions down …

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Measurement Of The Higher-Order Anisotropic Flow Coefficients For Identified Hadrons In Au + Au Collisions At √Snn =200 Gev, Andrew Marshall Adare, Baksay Gyöngyi, Baksay A. László, Marcus Hohlmann, Phenix Collaboration Jan 2016

Measurement Of The Higher-Order Anisotropic Flow Coefficients For Identified Hadrons In Au + Au Collisions At √Snn =200 Gev, Andrew Marshall Adare, Baksay Gyöngyi, Baksay A. László, Marcus Hohlmann, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Measurements of the anisotropic flow coefficients v₂{Ψ₂}, v₃{Ψ₃}, v₄{Ψ₄}, and v₄{Ψ₂} for identified particles (π±,K±, and p+p⁻) at midrapidity, obtained relative to the event planes Ψm at forward rapidities in Au + Au collisions at √sNN=200GeV, are presented as a function of collision centrality and particle transverse momenta pT. The vn coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic n, a modified valence quark-number Nq scaling [plotting vn{Ψm}/(Nq)n/2 versus transverse kinetic energies (KET)/Nq] is observed to yield a single curve for all the measured particle species for a broad range …

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Azimuthally Anisotropic Emission Of Low-Momentum Direct Photons In Au + Au Collisions At √Snn =200 Gev, Andrew Marshall Adare, Baksay Gyöngyi, Baksay A. László, Klaus Dehmelt, Marcus Hohlmann, Phenix Collaboration Jan 2016

Azimuthally Anisotropic Emission Of Low-Momentum Direct Photons In Au + Au Collisions At √Snn =200 Gev, Andrew Marshall Adare, Baksay Gyöngyi, Baksay A. László, Klaus Dehmelt, Marcus Hohlmann, Phenix Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider has measured second- and third-order Fourier coefficients of the azimuthal distributions of direct photons emitted at midrapidity in Au+Au collisions at √sNN=200 GeV for various collision centralities. Combining two different analysis techniques, results were obtained in the transverse momentum range of 0.4

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Measurement Of The Tt¯ Production Cross Section In The All-Jets Final State In Pp Collisions At √S = 8 Tev, Vardan Khachatryan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Himali Kalakhety, D. Noonan, Tuhin S. Roy, Francisco Yumiceva, The Cms Collaboration Jan 2016

Measurement Of The Tt¯ Production Cross Section In The All-Jets Final State In Pp Collisions At √S = 8 Tev, Vardan Khachatryan, Marc M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, Himali Kalakhety, D. Noonan, Tuhin S. Roy, Francisco Yumiceva, The Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

The cross section for tt¯ production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 fb−1fb−1. The inclusive cross section is found to be 275.6±6.1(stat)±37.8(syst)±7.2(lumi) pb. The normalized differential cross sections are measured as a function of the top quark transverse momenta, pT, and compared to predictions from quantum chromodynamics. The results are reported at detector, parton, and particle levels. In all cases, the measured top quark pT spectra are significantly softer than theoretical predictions.

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Modification Of The Lower Ionospheric Conductivity By Thunderstorm Electrostatic Fields, Mohammad A. Salem, Ningyu Liu, Hamid K. Rassoul Jan 2016

Modification Of The Lower Ionospheric Conductivity By Thunderstorm Electrostatic Fields, Mohammad A. Salem, Ningyu Liu, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

This paper reports a modeling study of the modifications of the nighttime lower ionospheric conductivity by electrostatic fields produced by underlying thunderstorms. The model used combines Ohm's law with a simplified lower ionospheric ion chemistry model to self-consistently calculate the steady state nighttime conductivity above a thunderstorm. The results indicate that although the electron density is generally increased, the lower ionospheric conductivity can be reduced by up to 1-2 orders of magnitude because electron mobility is significantly reduced due to the electron heating effect. For a typical ionospheric density profile, the resulting changes in the reflection heights of extremely low …

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Powerful Activity In The Bright Ages. I. A Visible/Ir Survey Of High Redshift 3c Radio Galaxies And Quasars, Bryan Hilbert, Eric S. Perlman Jan 2016

Powerful Activity In The Bright Ages. I. A Visible/Ir Survey Of High Redshift 3c Radio Galaxies And Quasars, Bryan Hilbert, Eric S. Perlman

Aerospace, Physics, and Space Science Faculty Publications

We present new rest-frame UV and visible observations of 22 high-z (1 < z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space Telescope's Wide Field Camera 3 instrument. Using a custom data reduction strategy in order to assure the removal of cosmic rays, persistence signal, and other data artifacts, we have produced high-quality science-ready images of the targets and their local environments. We observe targets with regions of UV emission suggestive of active star formation. In addition, several targets exhibit highly distorted host galaxy morphologies in the rest frame visible images. Photometric analyses reveal that brighter QSOs generally tend to be redder than their dimmer counterparts. Using emission line fluxes from the literature, we estimate that emission line contamination is relatively small in the rest frame UV images for the QSOs. Using archival VLA data, we have also created radio map overlays for each of our targets, allowing for analysis of the optical and radio axes alignment.

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Transit Timing Observations From Kepler. Ix. Catalog Of The Full Long-Cadence Data Set, Tomer Holczer, Tsevi Mazeh, Gil Nachmani, Daniel Jontof-Hutter, Eric B. Ford, Daniel Fabrycky, Darin Ragozzine, Mackenzie Kane, Jason H. Steffen Jan 2016

Transit Timing Observations From Kepler. Ix. Catalog Of The Full Long-Cadence Data Set, Tomer Holczer, Tsevi Mazeh, Gil Nachmani, Daniel Jontof-Hutter, Eric B. Ford, Daniel Fabrycky, Darin Ragozzine, Mackenzie Kane, Jason H. Steffen

Aerospace, Physics, and Space Science Faculty Publications

We present a new transit timing catalog of 2599 Kepler Objects of Interest (KOIs), using the PDC-MAP long-cadence light curves that include the full 17 quarters of the mission (ftp://wise-ftp.tau.ac.il/pub/tauttv/TTV/ver-112). The goal is to produce an easy-to-use catalog that can stimulate further analyses of interesting systems. For 779 KOIs with high enough S/N, we derived the timing, duration, and depth of 69,914 transits. For 1820 KOIs with lower SNR, we derived only the timing of 225,273 transits. After removal of outlier timings, we derived various statistics for each KOI that were used to indicate significant variations. Including systems found by …

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