Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “W BOSON”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Search for a Light Charged Higgs Boson Decaying to a W Boson and a C P -Odd Higgs Boson in Final States with e μ μ or μ μ μ in Proton-Proton Collisions at s = 13 TeV

A search for a light charged Higgs boson (H$^+$) decaying to a W boson and a CP-odd Higgs boson (A) in final states with e$\mu\mu$ or $\mu\mu\mu$ is performed using data from pp collisions at $\sqrt{s}=$ 13 TeV, recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 35.9 fb$^{-1}$. In this search, it is assumed that the H$^+$ boson is produced in decays of top quarks, and the A boson decays to two oppositely charged muons. The presence of signals for H$^+$ boson masses between 100 and 160 GeV and A boson masses between 15 and 75 GeV is investigated. No evidence for the production of the H$^+$ boson is found. Upper limits at 95% confidence level are obtained on the combined branching fraction for the decay chain t $\to$ bH$^+$ $\to$ bW$^+$A $\to$ bW$^+\mu^+\mu^-$, of 1.9 $\times$ 10$^{-6}$ to 8.6 $\times$ 10$^{-6}$, depending on the masses of the H$^+$ and A bosons. These are the first limits for these decay modes of the H$^+$ and A bosons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector

The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W' → WZ for bosons in the transverse momentum range 200 GeV < p T < 400 GeV in s= 8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of ϵ Z = 90 , 50, and 10 % , one can achieve W + -boson tagging rejection factors (1 / ϵ W+ ) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high p T , hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a tt¯ -enriched sample of events in 20.3 fb - 1 of data at √s= 8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Search for a high-mass Higgs boson decaying to a W boson pair in pp collisions at √s = 8 TeV with the ATLAS detector

A search for a high-mass Higgs boson H is performed in the H→WW→ℓνℓν and H→WW→ℓνqq decay channels, using pp collision data corresponding to an integrated luminosity of 20.3 fb -1 , collected at √s = 8 TeV by the ATLAS detector at the Large Hadron Collider. No evidence of a high-mass Higgs boson is found. Limits on σ H ×BR(H→WW) as a function of the Higgs boson mass mH are determined in three different scenarios: one in which the heavy Higgs boson has a narrow width compared to the experimental resolution, one a width increasing with the boson mass and modeled by the complex-pole scheme following the same behavior as in the Standard Model, and one for intermediate widths. The upper range of the search is m H =1500 GeV for the narrow-width scenario and m H =1000 GeV for the other two scenarios. The lower edge of the search range is 200-300 GeV and depends on the analysis channel and search scenario. For each scenario, individual and combined limits from the two WW decay channels are presented. At mH=1500 GeV, the highest mass point tested, σ H ∙BR(H→WW) for a narrow-width Higgs boson is constrained to be less than 22 fb and 6.6 fb at the 95% CL for the gluon fusion and vector-boson fusion production modes, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Search for doubly charged scalar bosons decaying into same-sign W boson pairs with the ATLAS detector

A search for doubly charged scalar bosons decaying into W boson pairs is presented. It uses a data sample from proton–proton collisions corresponding to an integrated luminosity of 36.1 fb -1 collected by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV in 2015 and 2016. This search is guided by a model that includes an extension of the Higgs sector through a scalar triplet, leading to a rich phenomenology that includes doubly charged scalar bosons H &#x00B1;<!-- ± --> &#x00B1;<!-- ± --> . Those bosons are produced in pairs in proton–proton collisions and decay predominantly into electroweak gauge bosons H &#x00B1;<!-- ± --> &#x00B1;<!-- ± --> &#x2192;<!-- → --> W &#x00B1;<!-- ± --> W &#x00B1;<!-- ± --> . Experimental signatures with several leptons, missing transverse energy and jets are explored. No significant deviations from the Standard Model predictions are found. The parameter space of the benchmark model is excluded at 95% confidence level for H &#x00B1;<!-- ± --> &#x00B1;<!-- ± --> bosons with masses between 200 and 220 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp collisions at 13 TeV with the ATLAS detector

This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, H→ aa, where the particle a decays to b-quarks and has a mass in the range of 20–60 GeV. The search is performed in events where the Higgs boson is produced in association with a W boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from b-quark decays. The analysis is based on the full dataset of pp collisions at $\sqrt{s}$=13 TeV recorded in 2015 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb -1 . No significant excess of events above the Standard Model prediction is observed, and a 95% confidence-level upper limit is derived for the product of the production cross section for pp→ WH times the branching ratio for the decay H→ aa→ 4 b. The upper limit ranges from 6.2 pb for an a-boson mass m a = 20 GeV to 1.5 pb for m a =60 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Search for W Boson Decays to Three Charged Pions

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb-1, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01×10-6 is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction. © 2019 CERN. for the CMS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 .

60 APPLIED LIFE SCIENCES↗
DOE OSTI2026

Measurement of the jet mass in hadronic decays of boosted W bosons at 13 TeV and extraction of the W boson mass

The jet mass of W bosons decaying to a quark-antiquark pair is measured in W+jets events from proton-proton collisions at a center-of-mass energy of 13 TeV. The data used were collected by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 138 fb −1 . Hadronic decays of W bosons with high momenta produce strongly collimated decay products due to the large Lorentz boost, and are reconstructed as single large-radius jets. These jets have a characteristic substructure that is exploited to distinguish them from the large background of quark- and gluon-initiated jets. The jet mass is computed using the soft-drop algorithm, which suppresses soft wide-angle radiation that leads to a broadening of the jet mass distribution. For the first time, unfolded measurements are presented of the double-differential W+jets cross section as a function of the jet transverse momentum and soft-drop mass. From these distributions, the W boson mass is obtained, with a value of 80.83 ± 0.55 GeV in a scheme with mass-dependent width, achieving the smallest uncertainty available today from an all-jets final state at a hadron collider.

hadron-hadron scattering↗
DOE OSTI2023

Search for a charged Higgs boson decaying into a heavy neutral Higgs boson and a W boson in proton-proton collisions at $ \sqrt{s}$ = 13 TeV

A search for a charged Higgs boson H ± decaying into a heavy neutral Higgs boson H and a W boson is presented. The analysis targets the H decay into a pair of tau leptons with at least one of them decaying hadronically and with an additional electron or muon present in the event. The search is based on proton-proton collision data recorded by the CMS experiment during 2016–2018 at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb –1 . The data are consistent with standard model background expectations. Upper limits at 95% confidence level are set on the product of the cross section and branching fraction for an H ± in the mass range of 300–700 GeV, assuming an H with a mass of 200 GeV. The observed limits range from 0.085 pb for an H ± mass of 300 Ge V to 0.019 pb for a mass of 700 GeV. These are the first limits on H ± production in the H ± → HW ± decay channel at the LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Measurement of the W Boson Production Charge Asymmetry in p p ¯ → W + X → e ν + X Events at s = 1.96 TeV

We present a measurement of the W boson production charge asymmetry in p$\bar{p}$→W+X→eν+X events at a center of mass energy of 1.96 TeV, using 9.7 fb -1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The neutrino longitudinal momentum is determined by using a neutrino weighting method, and the asymmetry is measured as a function of the W boson rapidity. The measurement extends over wider electron pseudorapidity region than previous results and is the most precise to date, allowing for precise determination of proton parton distribution functions in global fits.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Search for the Exclusive W Boson Hadronic Decays W ± → π ± γ, W ± → K ± γ and W ± → ρ ± γ with the ATLAS Detector

A search for the exclusive hadronic decays W ± → π ± γ, W ± → K ± γ, and W ± → ρ ± γ is performed using up to 140 fb -1 of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of $\sqrt{s} =$ 13 TeV. If observed, these rare processes would provide a unique test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders. Additionally, at future colliders, these decays could offer a new way to measure the W boson mass through fully reconstructed decay products. The search results in the most stringent upper limits to date on the branching fractions B(W ± → π ± γ) < 1.9 × 10 -6 , B(W ± → K ± γ) < 1.7 × 10 -6 , B(W ± → ρ ± γ) < 5.2 × 10 -6 at 95% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Measurement of differential cross sections and W+/W- cross-section ratios for W boson production in association with jets at $$ \sqrt{s}=8 $$ TeV with the ATLAS detector

This paper presents a measurement of the W boson production cross section and the W + /W - cross-section ratio, both in association with jets, in proton-proton collisions at $\sqrt{s}$ = 8 with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb -1 . Differential cross sections for events with at least one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles and the missing transverse momentum in the event, and the transverse momentum of the W boson. For a subset of the observables, the differential cross sections of positively and negatively charged W bosons are measured separately. In the cross-section ratio of W + /W - the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Search for a resonance decaying to a W boson and a photon in proton-proton collisions at $\sqrt{s}$ = 13 TeV using leptonic W boson decays

A search for a new charged particle X with mass between 0.3 and 2.0 TeV decaying to a W boson and a photon is presented, using proton-proton collision data at a center-of-mass energy of 13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138 fb$^{-1}$. Particle X has electric charge $\pm$ 1 and is assumed to have spin 0. The search is performed using the electron and muon decays of the W boson. No significant excess above the predicted background is observed. The upper limit at 95% confidence level on the product of the production cross section of the X and its branching fraction to a W boson and a photon is found to be 94 (137) fb for a 0.3 TeV resonance and 0.75 (0.81) fb for a 2.0 TeV resonance, for an X width-to-mass ratio of 0.01% (5%). This search presents the most stringent constraints to date on the existence of such resonances across the probed mass range. A statistical combination with an earlier study based on the hadronic decay mode of the W boson is also performed, and the upper limit at 95% confidence level for a 2.0 TeV resonance is reduced to 0.50 (0.63) fb for an X width-to-mass ratio of 0.01% (5%).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Measurement of the production of a W boson in association with a charm quark in pp collisions at $ \sqrt{s} $ = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb -1 of pp collision data at $ \sqrt{s} $ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96$ ^{+0.26}_{-0.30} $ at Q 2 = 1.9 GeV 2 , which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally the cross-section ratio σ(W + + $ \bar{c} $)/σ(W - +c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s–$ \bar{s} $ quark asymmetry.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for pair production of a new heavy quark that decays into a W boson and a light quark in p p collisions at s = 8 TeV with the ATLAS detector

We present a search for pair production of a new heavy quark ( Q ) that decays into a W boson and a light quark (q) in the final state where one W boson decays leptonically (to an electron or muon plus a neutrino) and the other W boson decays hadronically. The analysis is performed using an integrated luminosity of 20.3 fb -1 of pp collisions at $\sqrt{s}$ = 8 TeV collected by the ATLAS detector at the LHC. No evidence of $Q\overline{Q}$ production is observed. New chiral quarks with masses below 690 GeV are excluded at 95% confidence level, assuming BR ( Q → W q ) = 1 . Results are also interpreted in the context of vectorlike quark models, resulting in the limits on the mass of a vectorlike quark in the two-dimensional plane of BR ( Q → W q ) versus BR ( Q → H q ) .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗