Theoretical uncertainties in electroweak boson production cross sections at 7, 10, and 14 TeV at the LHC

Adam, N.; Halyo, V.; Yost, S. A.

doi:10.1007/jhep11(2010)074

Cited by 5 publications

(6 citation statements)

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“…QCD and EW results have to be combined together to obtain a realistic description of the DY final states: general purpose Shower Monte Carlo programs, like Pythia [55,56], Herwig [57] or Sherpa [58], include the possibility of multiple photon, gluon and quark emissions via a combined application of QCD and QED Parton Shower (PS), retaining only LL accuracy in the respective large logarithmic factors. In the absence of an exact calculation of the first mixed O(αα s ) corrections, several recipes have been devised to include the bulk of the two sets of effects including factorizable subleading effects both of QCD and EW origin [59][60][61][62][63][64], and preserving the NLO-QCD and NLO-EW accuracy on the quantities inclusive with respect to additional radiation [65][66][67].…”

Section: Existing Calculations and Simulation Codesmentioning

confidence: 99%

Precision measurement of the W -boson mass: Theoretical contributions and uncertainties

et al. 2017

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Abstract:We perform a comprehensive analysis of electroweak, QED and mixed QCDelectroweak corrections underlying the precise measurement of the W -boson mass M W at hadron colliders. By applying a template fitting technique, we detail the impact on M W of next-to-leading order electroweak and QCD corrections, multiple photon emission, lepton pair radiation and factorizable QCD-electroweak contributions. As a by-product, we provide an up-to-date estimate of the main theoretical uncertainties of perturbative nature. Our results can serve as a guideline for the assessment of the theoretical systematics at the Tevatron and LHC and allow a more robust precision measurement of the W -boson mass at hadron colliders.

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Section: Existing Calculations and Simulation Codesmentioning

confidence: 99%

Precision measurement of the W -boson mass: Theoretical contributions and uncertainties

et al. 2017

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“…However, data-to-theory comparisons using these tools at the level of detail performed for total cross sections in this paper would be arduous (see refs. [89][90][91] for some early NNLO fewz studies with leptonic cuts), due to the difficulty 5 in achieving sufficient numerical integration precision in a reasonable amount of CPU time, and the need for multiple independent runs to evaluate PDF uncertainties. The situation has improved recently with the release of the updated fewz 2.0 [92], with refined integration routines and automatic calculation of PDF uncertainties in a single run, but so far only for Z/γ * production.…”

Section: Measurements [3]mentioning

confidence: 99%

Parton distribution function dependence of benchmark Standard Model total cross sections at the 7 TeV LHC

Watt

2011

J. High Energ. Phys.

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We compare predictions for the W , Z, gg → H and tt total cross sections at the Large Hadron Collider (LHC), for a centre-of-mass energy of 7 TeV, using the most recent publicly available next-to-leading order and next-to-next-to-leading order parton distribution functions (PDFs) from all PDF fitting groups. In particular, we focus on the dependence on the different values of the strong coupling, α S (M 2 Z ), used by each group. We also perform a comparison of the relevant quark-antiquark and gluon-gluon luminosity functions. We make some comments on the recent PDF4LHC recommendations. Finally, we discuss the comparison of data and theory for W and Z cross sections at the LHC. Keywords: Hadronic Colliders, Standard Model, Deep Inelastic Scattering, Parton ModelArXiv ePrint: 1106.5788 2011. Searching for, or excluding, the Standard Model Higgs boson (H), produced mainly from gluon-gluon fusion through a top-quark loop, requires precise knowledge of the theoretical cross section. All these benchmark processes (W , Z, tt and gg → H) are sensitive to the parton distribution functions (PDFs) of the proton. The proton PDFs are determined by several groups from (global) analysis of a wide range of deep-inelastic scattering (DIS) and related hard-scattering data, taken at the HERA and Tevatron colliders and from fixed-target experiments at lower centre-of-mass energies; see refs. [12][13][14] for recent reviews.The aim of this paper is to compare next-to-leading order (NLO) and next-to-next-toleading order (NNLO) predictions, calculated within the standard framework of collinear factorisation, for the benchmark processes using the most recent publicly available PDFs from each group, all available using the current lhapdf V5.8.5 [15] interface. We will pay particular attention to the values of the strong coupling, α S , used by each fitting group and to the corresponding α S dependence of the benchmark cross sections. We do not aim to come up with a single "best" prediction for each of the benchmark cross sections together with a complete evaluation of all sources of theoretical uncertainty. We consider only uncertainties due to PDFs and α S on fixed-order (NLO and NNLO) predictions. We do not consider, for example, optimal (factorisation and renormalisation) scale choices and variations, electroweak corrections, or the effect of threshold resummation. For the gg → H process, we do not consider (C A π α S ) n -enhanced terms, use of a finite top-quark mass in the calculation of higher-order corrections, bottom-quark loop contributions, etc. Discussion of these issues can be found in the recent Handbook of LHC Higgs Cross Sections [16]. The findings regarding PDFs and α S reported here will be relevant also for more complete calculations, and the PDF and α S uncertainties often make up a sizeable or dominant part of the total theoretical uncertainty. We will present results only for total cross sections rather than differential distributions, and we do not attempt to account for the precise experimental cuts, although for...

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“…Its associated uncertainties comprise the dominant error on the Z→ee decay based luminosity measurement. The prediction is calculated at NNLO using the program FEWZ [67,68] with the MSTW08 [86] PDF set [89,90]. The cross section pertaining to the invariant mass window M ee ∈ (60, 120) GeV is:…”

Section: Resultsmentioning

confidence: 99%

Measurement of the Inclusive $Z \to ee$ Production Cross Section in Proton-Proton Collisions at $\sqrt{s}$ = 7TeV and $Z \to ee$ Decays as Standard Candles for Luminosity at the Large Hadron Collider

Werner¹

2011

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This thesis comprises a precision measurement of the inclusive Z→ee production cross section in proton-proton collisions provided by the Large Hadron Collider (LHC) at a center-of-mass energy of √ s = 7 TeV and the absolute luminosity based on Z→ee decays.The data was collected by the Compact Muon Solenoid (CMS) detector near Geneva, Switzerland during the year of 2010 and corresponds to an integrated luminosity of Ldt = 35.9 ± 1.4 pb −1 .Electronic decays of Z bosons allow one of the first electroweak measurements at the LHC, making the cross section measurement a benchmark of physics performance after the first year of CMS detector and LHC machine operations. It is the first systematic uncertainty limited Z→ee cross section measurement performed at √ s = 7 TeV. The measured cross section pertaining to the invariant mass window M ee ∈ (60, 120) GeV isagrees with the theoretical prediction calculated to NNLO in QCD.Leveraging Z→ee decays as "standard candles" for measuring the absolute luminosity at the LHC is examined; they are produced copiously, are well understood, and have clean detector signatures. Thus the consistency of the inclusive Z→ee production cross section measurement with the theoretical prediction motivates inverting the measurement to instead use the Z→ee signal yield to measure the luminosity. The result, which agrees with the primary relative CMS luminosity measurement calibrated using Van der Meer separation scans, is one of the most precise absolute luminosity measurements performed to date at a hadron collider and the first based on a physics signal at the LHC.iii I am forever indebted to my family for their enduring love and support: My wife Vanessa; father Paul; mother Dorothy; stepmother Connie; siblings Paul, John, Shannon, and Ryan; and all other family members, including my uncle Bob who needs recognition for his editing assistance. I owe much gratitude to my adviser Valerie Halyo for her steady guidance, deep physical insight, and infectious enthusiasm. I thank Dan Marlow for his support and direction, as well as all of the other outstanding professors at Princeton University with whom I've been fortunate enough to interact, including James Olsen for serving on my thesis committee. Likewise, I thank Paul Langacker of the Institute for Advanced Study for serving on my committee. I am also grateful to all of the excellent professors at UCLA who provided me with a high-caliber undergraduate physics foundation-especially Bob Cousins, whose continuing mentorship I've benefited greatly from. Thank you to Dmitry Bandurin, Jeff Berryhill, and Kalanand Mishra from whom I've learned a great deal and had long lasting and profitable collaborations. I'd like to thank Helmut Burkhardt and Simon White of the LHC team: Together we made Van der Meer scans at the LHC a reality. This research would not have been possible without CERN, Fermilab, the LHC team, the CMS collaboration, and all supporting agencies including the DOE: I am very much grateful for them. Finally, I must pay respect to my dear fri...

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Theoretical uncertainties in electroweak boson production cross sections at 7, 10, and 14 TeV at the LHC

Cited by 5 publications

References 55 publications

Precision measurement of the W -boson mass: Theoretical contributions and uncertainties

Precision measurement of the W -boson mass: Theoretical contributions and uncertainties

Parton distribution function dependence of benchmark Standard Model total cross sections at the 7 TeV LHC

Measurement of the Inclusive $Z \to ee$ Production Cross Section in Proton-Proton Collisions at $\sqrt{s}$ = 7TeV and $Z \to ee$ Decays as Standard Candles for Luminosity at the Large Hadron Collider

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