QED bremsstrahlung in decays of electroweak bosons

Arbuzov, A. B.; Sadykov, R.; Wa̧s, Z.

doi:10.1140/epjc/s10052-013-2625-1

Cited by 19 publications

(18 citation statements)

References 69 publications

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“…For both the electron and muon channels, the correction from the measured kinematics to the Born-level kinematics is included in the R and C factors respectively and can be as large as ∼ 30% for m ∼ 60 GeV due to wide-angle QED FSR radiation causing migration of events from the Z resonance peak to lower m . Very good agreement in the QED FSR predictions were found between Photos and Sanc [45]. The corrections to the dressed level, D, are also obtained from MC samples, and are close to unity, but increase close to m ll ∼ 60 GeV for the same reason since the ∆R = 0.1 cone does not include all photons from wide-angle radiation.…”

Section: Jhep06(2014)112supporting

confidence: 61%

Measurement of the low-mass Drell-Yan differential cross section at s $$ \sqrt{s} $$ = 7 TeV using the ATLAS detector

Aad

Abajyan

Abbott

et al. 2014

J. High Energ. Phys.

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The differential cross section for the process Z/γ * → ( = e, µ) as a function of dilepton invariant mass is measured in pp collisions at √ s = 7 TeV at the LHC using the ATLAS detector. The measurement is performed in the e and µ channels for invariant masses between 26 GeV and 66 GeV using an integrated luminosity of 1.6 fb −1 collected in 2011 and these measurements are combined. The analysis is extended to invariant masses as low as 12 GeV in the muon channel using 35 pb −1 of data collected in 2010. The cross sections are determined within fiducial acceptance regions and corrections to extrapolate the measurements to the full kinematic range are provided. Next-to-next-to-leading-order QCD predictions provide a significantly better description of the results than next-to-leadingorder QCD calculations, unless the latter are matched to a parton shower calculation. Keywords: Hadron-Hadron Scattering Conclusion 24The ATLAS collaboration 29 IntroductionThe Drell-Yan (DY) process of dilepton production in hadronic interactions [1] provides important information on the partonic structure of hadrons which is distinct from that obtained in deep inelastic scattering (DIS) measurements (for a recent review see ref.[2] and the references therein). Recent measurements from ATLAS [3, 4], CMS [5][6][7] and LHCb [8, 9] provide further information in a new kinematic domain. Measurements reported here are made below the mass of the Z resonance and extend to a lower invariant mass than previous ATLAS measurements. In addition the cross sections are normalized by luminosity rather than to the Z mass peak cross section. The data are compared to theoretical calculations of the DY process, which can now reliably be performed at nextto-next-to-leading-order (NNLO) precision [10][11][12][13]. Calculations at next-to-leading-order (NLO) accuracy are also available matched to resummations at leading-logarithm (LL) or next-to-leading logarithm (NLL) precision [14, 15] to accommodate soft collinear partonic emission in the initial state. A quantitative comparison of the data to the calculations is presented including a QCD fit to the parton distribution functions, and a detailed discussion of theoretical uncertainties is given.-1 - JHEP06(2014)112Measurements in the region of low dilepton invariant mass, m < 66 GeV, provide complementary constraints on the parton distribution functions (PDFs) to measurements near to the mass of the Z resonance. At low m , the cross section is dominated by the electromagnetic coupling of qq pairs to the virtual photon (γ * ), whereas at masses near the Z pole the axial and vector weak couplings of the qq pair to the Z boson dominate. Therefore the observations reported here have a different sensitivity to up-type and downtype quarks and anti-quarks compared to measurements near the Z resonance.The new kinematic region accessible at the LHC operating at a centre-of-mass energy of √ s = 7 TeV and the rapidity coverage of the ATLAS detector allow low partonic momentum fractions, x ∼ 3 × 10 −4 ...

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Section: Jhep06(2014)112supporting

confidence: 61%

Measurement of the low-mass Drell-Yan differential cross section at s $$ \sqrt{s} $$ = 7 TeV using the ATLAS detector

Aad

Abajyan

Abbott

et al. 2014

J. High Energ. Phys.

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“…This may be of interest to cross check the numerical importance of matrix element effect, which was missing for example in the FORTRAN implementation of PHOTOS. From our study [105] we conclude that the matrix element was necessary to improve precision from 0.3% of the FORTRAN version of PHOTOS to 0.2% precision level now. This uncertainty is for all QED final state emissions: photons, additional pairs and interference effect combined.…”

Section: Appendix A5: Photosmentioning

confidence: 76%

“…Finally let us point out that tests of Ref. [105] The common feature of the two packages is the treatment of the hard matrix elements with NLO QCD and NLO Electroweak (EW) corrections, supplemented with QCD and QED higher order contributions within the POWHEG framework. The QCD virtual corrections and real radiation matrix elements are the same as the ones contained in POWHEG_W(Z) [13], while the expressions of the virtual EW corrections are the ones publicly available in Ref.…”

Section: Appendix A5: Photosmentioning

confidence: 99%

Precision studies of observables in $$p p \rightarrow W \rightarrow l\nu _l$$ p p → W → l ν l and $$ pp \rightarrow \gamma ,Z \rightarrow l^+ l^-$$ p p → γ , Z → l + l - processes at the LHC

et al. 2017

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This report was prepared in the context of the LPCC Electroweak Precision Measurements at the LHC WG (https://lpcc.web.cern.ch/lpcc/index.php?page=electroweak_ wg) and summarizes the activity of a subgroup dedicated to the systematic comparison of public Monte Carlo codes, which describe the Drell-Yan processes at hadron colliders, in particular at the CERN Large Hadron Collider (LHC). This work represents an important step towards the definition of an accurate simulation framework necessary for very high-precision measurements of electroweak (EW) observables such as the W boson mass and the weak mixing angle. All the codes considered in this report share at least nexta e-mail: alessandro.vicini@mi.infn.it b e-mail: dow@ubpheno.physics.buffalo.edu to-leading-order (NLO) accuracy in the prediction of the total cross sections in an expansion either in the strong or in the EW coupling constant. The NLO fixed-order predictions have been scrutinized at the technical level, using exactly the same inputs, setup and perturbative accuracy, in order to quantify the level of agreement of different implementations of the same calculation. A dedicated comparison, again at the technical level, of three codes that reach next-to-nextto-leading-order (NNLO) accuracy in quantum chromodynamics (QCD) for the total cross section has also been performed. These fixed-order results are a well-defined reference that allows a classification of the impact of higher-order sets of radiative corrections. Several examples of higherorder effects due to the strong or the EW interaction are discussed in this common framework. Also the combination 123 280 Page 2 of 53 Eur. Phys. J. C (2017) 77 :280 of QCD and EW corrections is discussed, together with the ambiguities that affect the final result, due to the choice of a specific combination recipe. All the codes considered in this report have been run by the respective authors, and the results presented here constitute a benchmark that should be always checked/reproduced before any high-precision analysis is conducted based on these codes. In order to simplify these benchmarking procedures, the codes used in this report, together with the relevant input files and running instructions, can be found in a repository at https://twiki.cern.ch/twiki/ bin/view/Main/DrellYanComparison.

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“…The best description of its phase-space generation is given in [7]. Case of pair emission is quite analogous and the kinematical configuration for each decay is first deconvoluted into angular parametrization of two body decay into emitter and spectator 1 . The corresponding angles, together with extra generated ones, provide parametrization of four body phase space; all necessary phase-space Jacobians are calculated and taken into account.…”

Section: Pair Corrections In Photosmentioning

confidence: 99%

“…In the present note, we concentrate on effects and uncertainties related to emission of real lepton pair in association with Drell-Yan processes. Our work is a direct continuation of [1], that is why we will omit many definitions included in that paper. We will concentrate on the effects related to additional pair emissions in decays of heavy bosons, mainly Z.…”

Section: Introductionmentioning

confidence: 99%

Extra Lepton Pair Emission Corrections to Drell--Yan Processes in PHOTOS and SANC

Antropov¹,

Arbuzov²,

Sadykov³

et al. 2017

Acta Phys. Pol. B

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In the paper we present results for final state emissions of lepton pairs in decays of heavy intermediate states such as Z boson. Short presentations of PHOTOS and SANC algorithms and physics assumptions are given. Numerical distributions of relevance for LHC observables are shown. They are used in discussions of systematic errors in the predictions of pair emissions as implemented in the two programs. Suggestions for the future works are given. Present results confirm, that for the precision of 0.3% level, in simulation of final state the pair emissions can be avoided. For the precision of 0.1-0.2%, the results obtained with the presented programs should be enough. To cross precision tag of 0.1%, the further work is however required.

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QED bremsstrahlung in decays of electroweak bosons

Cited by 19 publications

References 69 publications

Measurement of the low-mass Drell-Yan differential cross section at s $$ \sqrt{s} $$ = 7 TeV using the ATLAS detector

Measurement of the low-mass Drell-Yan differential cross section at s $$ \sqrt{s} $$ = 7 TeV using the ATLAS detector

Precision studies of observables in $$p p \rightarrow W \rightarrow l\nu _l$$ p p → W → l ν l and $$ pp \rightarrow \gamma ,Z \rightarrow l^+ l^-$$ p p → γ , Z → l + l - processes at the LHC

Extra Lepton Pair Emission Corrections to Drell--Yan Processes in PHOTOS and SANC

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