Unambiguously Testing Positivity at Lepton Colliders
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
SEARCH · Engineering Papers
Results for “LEPTON”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Simultaneous Measurement of Proton and Lepton Kinematics in Quasielasticlike ν μ -Hydrocarbon Interactions from 2 to 20 GeV
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
And So Ad Infinitum: The Search for Quark and Lepton Substructure
The Victorian era mathematician, Augustus de Morgan wrote, “Great fleas have little fleas upon their backs to bite ‘em, And little fleas have lesser fleas, and so ad infinitum.” This parody of Jonathan Swift’s 1733 poem On Poetry: A Rhapsody arose from a literary history, but it is rather easy to see a metaphor for nature in these words. The saga of the search for the ultimate constituents of matter has long been one of finding a seemingly fundamental structure that, in turn, was found to be made of even smaller building blocks. Matter is made of molecules. Molecules are in turn made of atoms, which are themselves made of electrons and atomic nuclei. Furthermore, the nucleus consists of protons and neutrons, and these nucleons are composed of quarks.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Constraints on lepton number violation with the 2 tonne · year CUORE dataset
Matter-antimatter asymmetry underlines the incompleteness of the current understanding of particle physics. Neutrinoless double-beta decay (0νββ) may help explain this asymmetry while unveiling the Majorana nature of the neutrino. The CUORE (Cryogenic Underground Observatory for Rare Events) experiment searches for 0νββ of 130 Te using a tonne-scale cryogenic calorimeter operated at milli-kelvin temperatures. We report no evidence of 0νββ and place a lower limit on the half-life of T 1/2 > 3.5 × 10 25 years (90% credibility interval) with over 2 tonne·years of TeO 2 exposure. Finally, the tools and techniques developed for this result and the 5-year stable operation of nearly 1000 detectors demonstrate crucial infrastructure for future-generation experiments capable of searching for 0νββ across multiple isotopes.
Adams, D. Q. [Department of Physics and Astronomy,↗
Measurement of the product of the leptonic width of the J/ψ meson and the branching ratio for its decay to hadrons
A preliminary result of the KEDR/VEPP-4M experiment devoted to measuring the cross section for electron-positron annihilation to hadrons (e{sup +}e{sup −} → hadrons) in the energy region of J/ψ-resonance production is presented. The value found for the product of the J/ψ-meson width with respect to decay to electrons and the branching ratio for J/ψ-meson decay to hadrons is Γ{sub ee}B{sub h} = 4.67±0.04(stat.)± 0.22(syst.) keV.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Semileptonic (lepton, neutrino and jets) WW/WZ resonances searches at √s = 8 and 13 TeV with the ATLAS detector at the LHC
This talk presents the analyses results of the diboson (WW or WZ ) resonances production search in pp collisions at √s = 8 and 13 TeV with the ATLAS detector at the LHC with the semileptonic final state. As benchmark signal models Randall-Sundrum bulk model for KK G* → WW and Heavy Vector Triplet model for W′ → WZ and Z′ → WW are used. No significant excess for diboson resonances production is observed and upper limits on the production cross section times branching fraction of G*, W′ and Z′ are determined at 95% CL.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Lepton Pair Production in Neutrino–Nucleus Scattering
The impact of the emission of new light gauge bosons in neutrino–nucleus scattering on the observed signal is studied. As an example, a model with a neutral vector boson Z {sup ′} with a mass of a few tens of MeV, interacting with neutrinos via the V−A current, is considered. An equivalent Z {sup ′} boson spectrum for neutrinos is introduced. The corresponding correction to the total neutrino–nucleus scattering cross section as a function of the collision energy is calculated. This correction for several values of the model parameters allowed by the existing experimental bounds is presented.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for top-squark pair production in the single-lepton final state in pp collisions at $\sqrt{s}$ = 8 TeV
Abstract Not Provided
Chatrchyan, Serguei↗
Measurement of the $t\bar{t}$ production cross section in lepton+jets final states in pp collisions at 8 TeV and ratio of 8 to 7 TeV cross sections
A measurement of the top quark pair production ($t\bar{t}$) cross section in proton-proton collisions at the centre-of-mass energy of 8 TeV is presented using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6 fb$^{-1}$. This analysis is performed in the $t\bar{t}$ decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b~jet identification are determined from data. The measured $\mathrm{ t \bar{t} }$ cross section is 228.5 $\pm$ 3.8 (stat) $\pm$ 13.7 (syst) $\pm$ 6.0 (lumi) pb. This measurement is compared with an analysis of 7 TeV data, corresponding to an integrated luminosity of 5.0 fb$^{-1}$, to determine the ratio of 8 TeV to 7 TeV cross sections, which is found to be 1.43 $\pm$ 0.04 (stat) $\pm$ 0.07 (syst) $\pm$ 0.05 (lumi). Finally, the measurements are in agreement with QCD predictions up to next-to-next-to-leading order.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton–proton collisions at $$\sqrt{s} = 13\,\text {TeV} $$
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Erratum to: Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at $\sqrt{s}=8$ TeV with the ATLAS detector
In the original paper, Fig. 4 contains the wrong label preliminary. The label has been fixed, while none of the results have changed.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for new physics in events with a leptonically decaying Z boson and a large transverse momentum imbalance in proton–proton collisions at $\sqrt{s} $ = 13 $\,\text {TeV}$
A search for new physics in events with a Z boson produced in association with large missing transverse momentum at the LHC is presented. The search is based on the 2016 data sample of proton-proton collisions recorded with the CMS experiment at $\sqrt{s} = 13\,\text {TeV} $ , corresponding to an integrated luminosity of 35.9 $\,\text {fb}^{-1}$ . The results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like Higgs boson produced in association with the Z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. No significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel.
43 PARTICLE ACCELERATORS↗
Measurement of the top quark mass with lepton+jets final states using $\mathrm {p}$$ $$\mathrm {p}$ collisions at $\sqrt{s}=13\,\text {TeV} $
The mass of the top quark is measured using a sample of $\mathrm{t\overline{t}}$ events containing one isolated muon or electron and at least four jets in the final state, collected by the CMS detector using proton-proton collisions at $\sqrt{s}=$ 13 TeV at the CERN LHC. The events are selected from data corresponding to an integrated luminosity of 35.9 fb$^{-1}$. For each event the mass is reconstructed from a kinematic fit of the decay products to a \ttbar hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in $\mathrm{q\overline{q}'}$ decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be 172.25$\pm$0.08 (stat+JSF)$\pm$0.62 (syst) GeV. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of $\mathrm{t\overline{t}}$ production, and no indications of a bias in the measurements are observed.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Removal energies and final state interaction in lepton nucleus scattering
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for vector-like quarks in events with two oppositely charged leptons and jets in proton–proton collisions at $\sqrt{s} = 13\,\text {Te}\text {V} $
A search for the pair production of heavy vector-like partners $\mathrm {T}$ and $\mathrm {B}$ of the top and bottom quarks has been performed by the CMS experiment at the CERN LHC using proton–proton collisions at $\sqrt{s} = 13\,\text {Te}\text {V} $ . The data sample was collected in 2016 and corresponds to an integrated luminosity of 35.9 $\,\text {fb}^{-1}$ . Final states studied for $\mathrm {T} \overline{\mathrm {T}} $ production include those where one of the $\mathrm {T}$ quarks decays via $\mathrm {T} \rightarrow \mathrm {t}\mathrm {Z}$ and the other via $\mathrm {T} \rightarrow \mathrm {b}\mathrm {W}$ , $\mathrm {t}\mathrm {Z}$ , or $\mathrm {t}\mathrm {H} $ , where $\mathrm {H}$ is a Higgs boson. For the $\mathrm {B} \overline{\mathrm {B}} $ case, final states include those where one of the $\mathrm {B}$ quarks decays via $\mathrm {B} \rightarrow \mathrm {b}\mathrm {Z}$ and the other $\mathrm {B} \rightarrow \mathrm {t}\mathrm {W}$ , $\mathrm {b}\mathrm {Z}$ , or $\mathrm {b}\mathrm {H} $ . Events with two oppositely charged electrons or muons, consistent with coming from the decay of a $\mathrm {Z}$ boson, and jets are investigated. The number of observed events is consistent with standard model background estimations. Lower limits at 95% confidence level are placed on the masses of the $\mathrm {T}$ and $\mathrm {B}$ quarks for a range of branching fractions. Assuming 100% branching fractions for $\mathrm {T} \rightarrow \mathrm {t}\mathrm {Z}$ , and $\mathrm {B} \rightarrow \mathrm {b}\mathrm {Z}$ , $\mathrm {T}$ and $\mathrm {B}$ quark mass values below 1280 and 1130 $\,\text {Ge}\text {V}$ , respectively, are excluded.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗