Measurements Of Differential Cross Sections Research Articles

Measurement of the total and differential cross-sections of tt¯W\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}W $$\\end{document} production in pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV with the ATLAS detector

Measurements of inclusive and differential production cross-sections of a top-quark-top-antiquark pair in association with a W boson (tt¯W\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}W $$\\end{document}) are presented. They are performed by targeting final states with two same-sign or three isolated leptons (electrons or muons) and are based on s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV proton-proton collision data with an integrated luminosity of 140 fb−1, recorded from 2015 to 2018 with the ATLAS detector at the Large Hadron Collider. The inclusive tt¯W\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}W $$\\end{document} production cross-section is measured to be 880 ± 80 fb, compared to a reference theoretical prediction of 745 ± 50 (scale) ± 13 (2-loop approx.) ± 19 (PDF, αs) fb. Differential cross-section measurements characterise this process in detail for the first time. Several particle-level observables are compared with a variety of theoretical predictions, which generally agree well with the normalised differential cross-section results. Additionally, the relative charge asymmetry of tt¯W+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}{W}^{+} $$\\end{document} and tt¯W−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}{W}^{-} $$\\end{document} is measured inclusively to be ACrel\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {A}_{\ extrm{C}}^{\ extrm{rel}} $$\\end{document} = 0.33 ± 0.05, in very good agreement with the theoretical prediction of 0.322 ± 0.003 (scale) ± 0.007 (PDF), as well as differentially.

Test of CP-invariance of the Higgs boson in vector-boson fusion production and in its decay into four leptons

A search for CP violation in the decay kinematics and vector-boson fusion production of the Higgs boson is performed in the H → ZZ* → 4ℓ (ℓ = e, μ) decay channel. The results are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 13 TeV and recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. Matrix element-based optimal observables are used to constrain CP-odd couplings beyond the Standard Model in the framework of Standard Model effective field theory expressed in the Warsaw and Higgs bases. Differential fiducial cross-section measurements of the optimal observables are also performed, and a new fiducial cross-section measurement for vector-boson-fusion production is provided. All measurements are in agreement with the Standard Model prediction of a CP-even Higgs boson.

Angular differential cross section measurement for 11B(p, α0)8Be reaction with proton energy of 2.5 MeV

This report presents experimental differential cross section measurements at α0-particles’ eight outgoing angles of 50°, 70°, 90°, 106°, 120°, 130°, 150°, and 160° from 11B(p, α0)8Be reaction induced by 2.5 MeV proton beam bombarding on a natural boron target. The proton beams were accelerated by the 5SDH-2 pelletron at the University of Science - Hanoi National University (HUS). A good agreement has been observed between the obtained results and those from the literature. The importance of the data in a widely angular range is evidenced for the precise determination of the total integrated cross section.

Simple Lévy α-Stable Model Analysis of Elastic pp and pp¯ Low-|t| Data from SPS to LHC Energies

A simple Lévy α-stable (SL) model is used to describe the data on elastic pp and pp¯ scattering at low-|t| from SPS energies up to LHC energies. The SL model is demonstrated to describe the data with a strong non-exponential feature in a statistically acceptable manner. The energy dependence of the parameters of the model is determined and analyzed. The Lévy α parameter of the model has an energy-independent value of 1.959 ± 0.002 following from the strong non-exponential behavior of the data. We strengthen the conclusion that the discrepancy between TOTEM and ATLAS elastic pp differential cross section measurements arises only in the normalization and not in the shape of the distribution of the data as a function of t. We find that the slope parameter has different values for pp and pp¯ elastic scattering at LHC energies. This may be the effect of the odderon exchange or the jump in the energy dependence of the slope parameter in the energy interval 3 GeV ≲s≲ 4 GeV.

Differential cross-section measurements of the production of four charged leptons in association with two jets using the ATLAS detector

Differential cross-sections are measured for the production of four charged leptons in association with two jets. These measurements are sensitive to final states in which the jets are produced via the strong interaction as well as to the purely-electroweak vector boson scattering process. The analysis is performed using proton-proton collision data collected by ATLAS at sqrt{s} = 13 TeV and with an integrated luminosity of 140 fb−1. The data are corrected for the effects of detector inefficiency and resolution and are compared to state-of-the-art Monte Carlo event generator predictions. The differential cross-sections are used to search for anomalous weak-boson self-interactions that are induced by dimension-six and dimension-eight operators in Standard Model effective field theory.

Total and Double Differential Scattering Cross-Section Measurements of Isotropic Graphite

Total and Double Differential Scattering Cross-Section Measurements of Isotropic Graphite

Differential cross–section measurements for the proton-induced alpha and deuteron reactions and elastic scattering on 9Be, suitable for Ion beam analysis applications

In the current work the differential cross sections for the proton-induced 9Be(p,d0)8Be and 9Be(p,α0)6Li nuclear reactions (Q-values = 559 and 2125 keV respectively), as well as, the 9Be(p,p0)9Be elastic scattering were measured for 6 backscattering detection angles (θ = 120°, 130°, 140°, 150°, 160° and 170°) covering the Ep,lab = 300–3000 keV energy range with an energy step between 10 and 50 keV. The total estimated uncertainties of the determined cross-section values did not exceed 6.4 % for the elastic scattering, 7.0 % for the 9Be(p,α0)6Li and 9.9 % for the 9Be(p,d0)8Be reaction. Benchmarking measurements were also performed with a suitable thick target in order to validate the obtained cross-section values. The present experimental results constitute three coherent differential cross-section datasets suitable for IBA applications. The measurements were performed at the 4 MV Tandem Dynamitron Laboratory of the Ruhr University Bochum in Germany. The experimental, data analysis and benchmarking procedures are presented in detail.

Top Quarks from Tevatron to the LHC

Recent measurements in the top quark sector at the CERN Large Hadron Collider are discussed. This review discusses the most recent measurements of inclusive and differential top quark cross-sections in strong and electroweak production of top quarks and related measurements, such as top quark properties, as well as searches, including EFT approaches.

Measurements of differential cross sections of Higgs boson production through gluon fusion in the Hrightarrow WW^{*}rightarrow enu mu nu final state at sqrt{s} = 13 TeV with the ATLAS detector

Higgs boson production via gluon–gluon fusion is measured in the WW^{*} rightarrow enu mu nu decay channel. The dataset utilized corresponds to an integrated luminosity of 139 fb^{-1} collected by the ATLAS detector from sqrt{s}=13 TeV proton–proton collisions delivered by the Large Hadron Collider between 2015 and 2018. Differential cross sections are measured in a fiducial phase space restricted to the production of at most one additional jet. The results are consistent with Standard Model expectations, derived using different Monte Carlo generators.

Measurements of W^{+}W^{-} production in decay topologies inspired by searches for electroweak supersymmetry

This paper presents a measurement of fiducial and differential cross-sections for W^{+}W^{-} production in proton–proton collisions at sqrt{s}=13 TeV with the ATLAS experiment at the Large Hadron Collider using a dataset corresponding to an integrated luminosity of 139 fb^{-1}. Events with exactly one electron, one muon and no hadronic jets are studied. The fiducial region in which the measurements are performed is inspired by searches for the electroweak production of supersymmetric charginos decaying to two-lepton final states. The selected events have moderate values of missing transverse momentum and the ‘stransverse mass’ variable m_{textrm{T2}}, which is widely used in searches for supersymmetry at the LHC. The ranges of these variables are chosen so that the acceptance is enhanced for direct W^{+}W^{-} production and suppressed for production via top quarks, which is treated as a background. The fiducial cross-section and particle-level differential cross-sections for six variables are measured and compared with two theoretical SM predictions from perturbative QCD calculations.

Measurements of inclusive and differential cross sections for the Higgs boson production and decay to four-leptons in proton-proton collisions at sqrt{s} = 13 TeV

Measurements of the inclusive and differential fiducial cross sections for the Higgs boson production in the H → ZZ → 4ℓ (ℓ = e, μ) decay channel are presented. The results are obtained from the analysis of proton-proton collision data recorded by the CMS experiment at the CERN LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb−1. The measured inclusive fiducial cross section is 2.73 ± 0.26 fb, in agreement with the standard model expectation of 2.86 ± 0.1 fb. Differential cross sections are measured as a function of several kinematic observables sensitive to the Higgs boson production and decay to four leptons. A set of double-differential measurements is also performed, yielding a comprehensive characterization of the four leptons final state. Constraints on the Higgs boson trilinear coupling and on the bottom and charm quark coupling modifiers are derived from its transverse momentum distribution. All results are consistent with theoretical predictions from the standard model.

Inclusive-photon production and its dependence on photon isolation in pp collisions at sqrt{s} = 13 TeV using 139 fb−1 of ATLAS data

Measurements of differential cross sections are presented for inclusive isolated-photon production in pp collisions at a centre-of-mass energy of 13 TeV provided by the LHC and using 139 fb−1 of data recorded by the ATLAS experiment. The cross sections are measured as functions of the photon transverse energy in different regions of photon pseudorapidity. The photons are required to be isolated by means of a fixed-cone method with two different cone radii. The dependence of the inclusive-photon production on the photon isolation is investigated by measuring the fiducial cross sections as functions of the isolation-cone radius and the ratios of the differential cross sections with different radii in different regions of photon pseudorapidity. The results presented in this paper constitute an improvement with respect to those published by ATLAS earlier: the measurements are provided for different isolation radii and with a more granular segmentation in photon pseudorapidity that can be exploited in improving the determination of the proton parton distribution functions. These improvements provide a more in-depth test of the theoretical predictions. Next-to-leading-order QCD predictions from JETPHOX and SHERPA and next-to-next-to-leading-order QCD predictions from NNLOJET are compared to the measurements, using several parameterisations of the proton parton distribution functions. The measured cross sections are well described by the fixed-order QCD predictions within the experimental and theoretical uncertainties in most of the investigated phase-space region.

Measurements of Zγ+jets differential cross sections in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

Differential cross-section measurements of Zγ production in association with hadronic jets are presented, using the full 139 fb−1 dataset of sqrt{s} = 13 TeV proton–proton collisions collected by the ATLAS detector during Run 2 of the LHC. Distributions are measured using events in which the Z boson decays leptonically and the photon is usually radiated from an initial-state quark. Measurements are made in both one and two observables, including those sensitive to the hard scattering in the event and others which probe additional soft and collinear radiation. Different Standard Model predictions, from both parton-shower Monte Carlo simulation and fixed-order QCD calculations, are compared with the measurements. In general, good agreement is observed between data and predictions from MATRIX and MiNNLOPS, as well as next-to-leading-order predictions from MadGraph5_aMC@NLO and Sherpa.

Measurement of inclusive and differential cross sections for single top quark production in association with a W boson in proton-proton collisions at sqrt{s} = 13 TeV

Measurements of the inclusive and normalised differential cross sections are presented for the production of single top quarks in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data used were recorded with the CMS detector at the LHC during 2016–2018, and correspond to an integrated luminosity of 138 fb−1. Events containing one electron and one muon in the final state are analysed. For the inclusive measurement, a multivariate discriminant, exploiting the kinematic properties of the events is used to separate the signal from the dominant textrm{t}overline{textrm{t}} background. A cross section of 79.2pm 0.9{left(textrm{stat}right)}_{-8.0}^{+7.7}left(textrm{syst}right)pm 1.2left(textrm{lumi}right) pb is obtained, consistent with the predictions of the standard model. For the differential measurements, a fiducial region is defined according to the detector acceptance, and the requirement of exactly one jet coming from the fragmentation of a bottom quark. The resulting distributions are unfolded to particle level and agree with the predictions at next-to-leading order in perturbative quantum chromodynamics.

Differential cross-section measurements for the 9Be(3He,3He0)9Be elastic scattering and the 9Be(3He,px)11B reactions

The differential cross sections of 9Be(3He,3He0)9Be elastic scattering and of the 9Be(3He,p0,1,2,3,4+5,6,7)11B reactions have been determined in the energy range from 1.6 to 6 MeV at six backward angles from 120° to 170°, with a step of 10°. The experiments were performed at the 4 MV Dynamitron Tandem Laboratory of the Central Unit for Ion Beams and Radionuclides of the Ruhr University Bochum in Germany. The obtained datasets have been validated through benchmarking experiments, at 8 beam energies, using a thick, high-purity, beryllium foil. The results of the present work are compared with existing ones from literature and any discrepancies observed are discussed.

Measurements of the Kr (e,2e) differential cross section in the perpendicular plane from 2 to 120 eV above the ionization threshold

New (e, 2e) differential cross section measurements from krypton are presented in the perpendicular plane, where the incident electron beam is orthogonal to the scattered and ejected electrons that map out a detection plane. New data were obtained at incident energies from 30 eV to 120 eV above the ionization potential (IP), the experiment being configured to detect scattered and ejected electrons with equal energy. The results are compared to previous measurements from 2 eV to 50 eV above the IP and to calculations from different models in this energy range. The new experiments confirm the results from previous measurements. The results are also compared to recent data for argon acquired under the same kinematic conditions, to highlight similarities and differences that are observed.

Measurement of differential cross sections for proton elastic scattering on natO at Ep= 4-6 MeV, suitable for EBS

In this study we present the experimental differential cross sections of natO(p,p0) elastic scattering, determined via the relative measurement technique, in the proton beam energy range Elab=4-6 MeV with a varying step (from 5-15 keV), at six backscattering detector angles between 120o and 170o (every 10o). A thin, self-supporting target manufactured in the lab was used in this experiment and the determination of its stoichiometry was carried out according to the currently existing evaluation, which has also been benchmarked recently. The measurements were performed using the Van de Graaff Tandem 5.5 MV Accelerator of N.C.S.R. “Demokritos” in Athens, Greece. The differential cross-section datasets obtained in the present work and already existing ones in literature for this extended proton beam energy range are shown and the observed peculiarities and discrepancies are discussed and analyzed.

Differential cross-section measurements of the 11B(d, pγ1,2)12B reactions for analytical applications

In the present work, the 11B(d, pγ)12B differential cross-sections for gamma- rays originating from the first two excited states of the 12B at 953 and 1674 keV were measured in the energy range Ed,lab = 671–1990 keV with steps of 30 or 40 keV at a detection angle of 90°. The target was a thin natB2O3 film evaporated onto a self-supporting Ag layer. The thick target gamma-ray yields were measured in the same experimental setup using a pressed pellet made of natB powder. The obtained results were compared with the existing data in literature. The validity of measured cross-sections was checked through a thick target benchmarking experiment.

Differential cross-section measurements of the 6Li(d,nʹγ)7Be, 6Li(d,pʹγ)7Li, 7Li(d,dʹγ)7Li and 19F(d,pʹγ)20F reactions suitable for PIGE applications

Differential cross sections of the 6Li(d,nʹγ)7Be, 6Li(d,pʹγ)7Li, 7Li(d,dʹγ)7Li and 19F(d,pʹγ)20F reactions were determined at three detection angles (0°, 55° and 90°), for deuteron energies ranging from 1000 keV up to 2200 keV, with a 20 keV step. For the detection of the γ-ray peaks of interest at Eγ = 429 keV, Eγ = 478 keV and Eγ = 656 keV, two different LiF targets were used. Three HPGe detectors having a 80% relative efficiency were placed around the targets for the detection of the gamma-ray peaks under study. The present results are compared with existing ones from the literature and the erroneous omission of the 7Li(d,dʹγ)7Li reaction contribution in the yield of the 478 gamma ray in natLi targets is discussed and analyzed. Comparisons with previously reported absolute thick target yields are also performed. Despite the fact that the differential cross sections determined in the present work are in very good agreement with previously reported differential cross-section datasets in literature (properly corrected), remarkable discrepancies in the case of existing absolute thick target yields are observed.

Differential cross section measurements of the 7Li (p,p΄γ1-0) 7Li reaction suitable for PIGE applications

Differential cross sections of the reaction 7Li(p,p΄γ1-0)7Li were experimentally determined in the proton energy range between 1000 and 4000 keV. The experiment was conducted at the Tandem Accelerator Laboratory of N.C.S.R. “Demokritos”. The detection of the emitted gamma rays, having an energy Eγ = 477.6 keV, was accomplished using four HPGe detectors of relative efficiency varying between 18 and 80%, at the detection angles of 0°, 55°, 90° and 165°. The statistical errors of the measurements did not exceed 4%, while the overall systematic uncertainty budget was also kept as low as possible (∼8%). For the validation of the obtained cross sections a benchmarking experiment was performed using a thick target of known stoichiometry. The comparison with existing experimental datasets in literature is also presented and discussed.