title: Specialized minimal PDFs for optimized LHC calculations.
abstract: We present a methodology for the construction of parton distribution functions (PDFs) designed to provide an accurate representation of PDF uncertainties for specific processes or classes of processes with a minimal number of PDF error sets: specialized minimal PDF sets, or SM-PDFs. We construct these SM-PDFs in such a way that sets corresponding to different input processes can be combined without losing information, specifically as regards their correlations, and that they are robust upon smooth variations of the kinematic cuts. The proposed strategy never discards information, so that the SM-PDF sets can be enlarged by the addition of new processes, until the prior PDF set is eventually recovered for a large enough set of processes. We illustrate the method by producing SM-PDFs tailored to Higgs, top-quark pair, and electroweak gauge boson physics, and we determine that, when the PDF4LHC15 combined set is used as the prior, around 11, 4, and 11 Hessian eigenvectors, respectively, are enough to fully describe the corresponding processes.
authors.affiliation: TIF Lab, Dipartimento di Fisica, Università di Milano, Via Celoria 16, Milan, 20133 Italy ; Sezione di Milano, INFN, Via Celoria 16, Milan, 20133 Italy ; Theory Department, CERN, Geneva, 1211 Switzerland.
authors.forename: Stefano
authors.initials: S
authors.lastname: Carrazza
authors.affiliation: TIF Lab, Dipartimento di Fisica, Università di Milano, Via Celoria 16, Milan, 20133 Italy ; Sezione di Milano, INFN, Via Celoria 16, Milan, 20133 Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Forte
authors.affiliation: TIF Lab, Dipartimento di Fisica, Università di Milano, Via Celoria 16, Milan, 20133 Italy ; Sezione di Milano, INFN, Via Celoria 16, Milan, 20133 Italy ; Dipartimento di Fisica, Università di Torino, Via Pietro Giuria 1, Turin, 10125 Italy ; Sezione di Torino, INFN, Via Pietro Giuria 1, Turin, 10125 Italy.
authors.forename: Zahari
authors.initials: Z
authors.lastname: Kassabov
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, OX1 3NP Oxford, UK.
authors.forename: Juan
authors.initials: J
authors.lastname: Rojo