Reweighting NNPDFs: the W lepton asymmetry

The NNPDF Collaboration, Richard D. Ball, Valerio Bertone, Francesco Cerutti, Luigi Del Debbio, Stefano Forte, Alberto Guffanti, Jose I. Latorre, Juan Rojo, Maria Ubiali

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

We present a method for incorporating the information contained in new datasets into an existing set of parton distribution functions without the need for refitting. The method involves reweighting the ensemble of parton densities through the computation of the chi-square to the new dataset. We explain how reweighting may be used to assess the impact of any new data or pseudodata on parton densities and thus on their predictions. We show that the method works by considering the addition of inclusive jet data to a DIS+DY fit, and comparing to the refitted distribution. We then use reweighting to determine the impact of recent high statistics lepton asymmetry data from the D0 experiment on the NNPDF2.0 parton set. We find that the D0 inclusive muon and electron data are perfectly compatible with the rest of the data included in the NNPDF2.0 analysis and impose additional constraints on the large-x d/u ratio. The more exclusive D0 electron datasets are however inconsistent both with the other datasets and among themselves, suggesting that here the experimental uncertainties have been underestimated.
Original languageEnglish
Pages (from-to)112-143
JournalNuclear Physics B
Volume849
Issue number1
DOIs
Publication statusPublished - 3 Dec 2010

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partons
leptons
asymmetry
distributed interactive simulation
muons
electrons
distribution functions
statistics
predictions

Bibliographical note

36 pages, 22 figures: errors in Eqns.12,36,37 corrected and parts of Figs.1,6,10,13,15,19 replaced

Keywords

  • hep-ph
  • hep-ex

Cite this

Collaboration, T. NNPDF., Ball, R. D., Bertone, V., Cerutti, F., Debbio, L. D., Forte, S., ... Ubiali, M. (2010). Reweighting NNPDFs: the W lepton asymmetry. Nuclear Physics B, 849(1), 112-143. https://doi.org/10.1016/j.nuclphysb.2011.03.017
Collaboration, The NNPDF ; Ball, Richard D. ; Bertone, Valerio ; Cerutti, Francesco ; Debbio, Luigi Del ; Forte, Stefano ; Guffanti, Alberto ; Latorre, Jose I. ; Rojo, Juan ; Ubiali, Maria. / Reweighting NNPDFs : the W lepton asymmetry. In: Nuclear Physics B. 2010 ; Vol. 849, No. 1. pp. 112-143.
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abstract = "We present a method for incorporating the information contained in new datasets into an existing set of parton distribution functions without the need for refitting. The method involves reweighting the ensemble of parton densities through the computation of the chi-square to the new dataset. We explain how reweighting may be used to assess the impact of any new data or pseudodata on parton densities and thus on their predictions. We show that the method works by considering the addition of inclusive jet data to a DIS+DY fit, and comparing to the refitted distribution. We then use reweighting to determine the impact of recent high statistics lepton asymmetry data from the D0 experiment on the NNPDF2.0 parton set. We find that the D0 inclusive muon and electron data are perfectly compatible with the rest of the data included in the NNPDF2.0 analysis and impose additional constraints on the large-x d/u ratio. The more exclusive D0 electron datasets are however inconsistent both with the other datasets and among themselves, suggesting that here the experimental uncertainties have been underestimated.",
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Collaboration, TNNPDF, Ball, RD, Bertone, V, Cerutti, F, Debbio, LD, Forte, S, Guffanti, A, Latorre, JI, Rojo, J & Ubiali, M 2010, 'Reweighting NNPDFs: the W lepton asymmetry' Nuclear Physics B, vol. 849, no. 1, pp. 112-143. https://doi.org/10.1016/j.nuclphysb.2011.03.017

Reweighting NNPDFs : the W lepton asymmetry. / Collaboration, The NNPDF; Ball, Richard D.; Bertone, Valerio; Cerutti, Francesco; Debbio, Luigi Del; Forte, Stefano; Guffanti, Alberto; Latorre, Jose I.; Rojo, Juan; Ubiali, Maria.

In: Nuclear Physics B, Vol. 849, No. 1, 03.12.2010, p. 112-143.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Reweighting NNPDFs

T2 - the W lepton asymmetry

AU - Collaboration, The NNPDF

AU - Ball, Richard D.

AU - Bertone, Valerio

AU - Cerutti, Francesco

AU - Debbio, Luigi Del

AU - Forte, Stefano

AU - Guffanti, Alberto

AU - Latorre, Jose I.

AU - Rojo, Juan

AU - Ubiali, Maria

N1 - 36 pages, 22 figures: errors in Eqns.12,36,37 corrected and parts of Figs.1,6,10,13,15,19 replaced

PY - 2010/12/3

Y1 - 2010/12/3

N2 - We present a method for incorporating the information contained in new datasets into an existing set of parton distribution functions without the need for refitting. The method involves reweighting the ensemble of parton densities through the computation of the chi-square to the new dataset. We explain how reweighting may be used to assess the impact of any new data or pseudodata on parton densities and thus on their predictions. We show that the method works by considering the addition of inclusive jet data to a DIS+DY fit, and comparing to the refitted distribution. We then use reweighting to determine the impact of recent high statistics lepton asymmetry data from the D0 experiment on the NNPDF2.0 parton set. We find that the D0 inclusive muon and electron data are perfectly compatible with the rest of the data included in the NNPDF2.0 analysis and impose additional constraints on the large-x d/u ratio. The more exclusive D0 electron datasets are however inconsistent both with the other datasets and among themselves, suggesting that here the experimental uncertainties have been underestimated.

AB - We present a method for incorporating the information contained in new datasets into an existing set of parton distribution functions without the need for refitting. The method involves reweighting the ensemble of parton densities through the computation of the chi-square to the new dataset. We explain how reweighting may be used to assess the impact of any new data or pseudodata on parton densities and thus on their predictions. We show that the method works by considering the addition of inclusive jet data to a DIS+DY fit, and comparing to the refitted distribution. We then use reweighting to determine the impact of recent high statistics lepton asymmetry data from the D0 experiment on the NNPDF2.0 parton set. We find that the D0 inclusive muon and electron data are perfectly compatible with the rest of the data included in the NNPDF2.0 analysis and impose additional constraints on the large-x d/u ratio. The more exclusive D0 electron datasets are however inconsistent both with the other datasets and among themselves, suggesting that here the experimental uncertainties have been underestimated.

KW - hep-ph

KW - hep-ex

U2 - 10.1016/j.nuclphysb.2011.03.017

DO - 10.1016/j.nuclphysb.2011.03.017

M3 - Article

VL - 849

SP - 112

EP - 143

JO - Nuclear Physics B

JF - Nuclear Physics B

SN - 0550-3213

IS - 1

ER -

Collaboration TNNPDF, Ball RD, Bertone V, Cerutti F, Debbio LD, Forte S et al. Reweighting NNPDFs: the W lepton asymmetry. Nuclear Physics B. 2010 Dec 3;849(1):112-143. https://doi.org/10.1016/j.nuclphysb.2011.03.017