### Abstract

Original language | English |
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Pages (from-to) | 311-338 |

Number of pages | 28 |

Journal | Nuclear Physics B |

Volume | 860 |

Issue number | 3 |

DOIs | |

Publication status | Published - 8 Feb 2012 |

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*Nuclear Physics B*, vol. 860, no. 3, pp. 311-338. https://doi.org/10.1016/j.nuclphysb.2012.03.003

**Quantitative constraints on the gluon distribution function in the proton from collider isolated-photon data.** / d'Enterria, David; Rojo, Juan.

Research output: Contribution to Journal › Article › Academic › peer-review

TY - JOUR

T1 - Quantitative constraints on the gluon distribution function in the proton from collider isolated-photon data

AU - d'Enterria, David

AU - Rojo, Juan

PY - 2012/2/8

Y1 - 2012/2/8

N2 - The impact of isolated-photon data from proton–(anti)proton collisions at RHIC, SpView the MathML sourcep¯S, Tevatron and LHC energies, on the parton distribution functions of the proton is studied using a recently developed Bayesian reweighting method. The impact on the gluon density of the 35 existing isolated-γ measurements is quantified using next-to-leading order (NLO) perturbative QCD calculations complemented with the NNPDF2.1 parton densities. The NLO predictions are found to describe well most of the datasets from 200 GeV up to 7 TeV centre-of-mass energies. The isolated-photon spectra recently measured at the LHC are precise enough to constrain the gluon distribution and lead to a moderate reduction (up to 20%) of its uncertainties around fractional momenta x≈0.02x≈0.02. As a particular case, we show that the improved gluon density reduces the PDF uncertainty for the Higgs boson production cross section in the gluon-fusion channel by more than 20% at the LHC. We conclude that present and future isolated-photon measurements constitute an interesting addition to coming global PDF analyses.

AB - The impact of isolated-photon data from proton–(anti)proton collisions at RHIC, SpView the MathML sourcep¯S, Tevatron and LHC energies, on the parton distribution functions of the proton is studied using a recently developed Bayesian reweighting method. The impact on the gluon density of the 35 existing isolated-γ measurements is quantified using next-to-leading order (NLO) perturbative QCD calculations complemented with the NNPDF2.1 parton densities. The NLO predictions are found to describe well most of the datasets from 200 GeV up to 7 TeV centre-of-mass energies. The isolated-photon spectra recently measured at the LHC are precise enough to constrain the gluon distribution and lead to a moderate reduction (up to 20%) of its uncertainties around fractional momenta x≈0.02x≈0.02. As a particular case, we show that the improved gluon density reduces the PDF uncertainty for the Higgs boson production cross section in the gluon-fusion channel by more than 20% at the LHC. We conclude that present and future isolated-photon measurements constitute an interesting addition to coming global PDF analyses.

U2 - 10.1016/j.nuclphysb.2012.03.003

DO - 10.1016/j.nuclphysb.2012.03.003

M3 - Article

VL - 860

SP - 311

EP - 338

JO - Nuclear Physics B

JF - Nuclear Physics B

SN - 0550-3213

IS - 3

ER -