SM on Emanuele Bagnaschi's home page https://www.bagnaschi.eu/tags/sm/ Recent content in SM on Emanuele Bagnaschi's home page Hugo -- gohugo.io en Sun, 29 Nov 2020 15:50:06 +0100 A new look at the estimation of the PDF uncertainties in the determination of electroweak parameters at hadron colliders https://www.bagnaschi.eu/science/articles/mw_pdf/ Sun, 29 Nov 2020 15:50:06 +0100 https://www.bagnaschi.eu/science/articles/mw_pdf/ Emanuele Bagnaschi (PSI), Alessandro Vicini (CERN and INFN Milan) e-Print: 1910.04726 [hep-ph] We discuss the determination of electroweak parameters from hadron collider observables, focusing on the W boson mass measurement. We revise the procedures adopted in the literature to include in the experimental analysis the uncertainty due to our imperfect knowledge of the proton structure. We show how the treatment of the proton parton density functions (PDFs) uncertainty as a source of systematic error, leads to the automatic inclusion in the fit of the bin-bin correlation of the kinematic distributions with respect to PDF variations. Resummation ambiguities in the Higgs transverse-momentum spectrum in the Standard Model and beyond https://www.bagnaschi.eu/science/articles/higgs_pt_resumm/ Sun, 29 Nov 2020 13:07:49 +0100 https://www.bagnaschi.eu/science/articles/higgs_pt_resumm/ Emanuele Bagnaschi (DESY), Robert V. Harlander (Bergische U., Wuppertal (main)), Hendrik Mantler(CERN and Karlsruhe U., ITP and KIT, Karlsruhe, IKP), Alessandro Vicini (INFN, Milan and Milan U.), Marius Wiesemann (Zurich U.) JHEP 01 (2016) 090 DOI: 10.1007/JHEP01(2016)090 e-print: 1510.08850 [hep-ph] We study the prediction for the Higgs transverse momentum distribution in gluon fusion and focus on the problem of matching fixed- and all-order perturbative results. The main sources of matching ambiguities on this distribution are investigated by means of a twofold comparison. The Higgs transverse momentum distribution in gluon fusion as a multiscale problem https://www.bagnaschi.eu/science/articles/higgs_pt_multiscale/ Sun, 29 Nov 2020 12:38:56 +0100 https://www.bagnaschi.eu/science/articles/higgs_pt_multiscale/ Emanuele Bagnaschi (DESY) and Alessandro Vicini (INFN, Milan and Milan U.) JHEP 01 (2016) 056 DOI: 10.1007/JHEP01(2016)056 e-print: 1505.00735 [hep-ph] We consider Higgs production in gluon fusion and in particular the prediction of the Higgs transverse momentum distribution. We discuss the ambiguities affecting the matching procedure between fixed order matrix elements and the resummation to all orders of the terms enhanced by $\log(p_{T}^{H}/m_{H}​)$ factors. Following a recent proposal, we argue that the gluon fusion process, computed considering two active quark flavors, is a multiscale problem from the point of view of the resummation of the collinear singular terms. Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM https://www.bagnaschi.eu/science/articles/gghnlopowheg/ Wed, 19 Aug 2020 23:19:05 +0200 https://www.bagnaschi.eu/science/articles/gghnlopowheg/ E. Bagnaschi (Milan U. & INFN, Milan & Paris, LPTHE) , G. Degrassi (INFN, Rome3 & Rome III U.) , P. Slavich (Paris, LPTHE) , A. Vicini (Milan U. & INFN, Milan) JHEP 1202 (2012) 088 DOI: 10.1007/JHEP02(2012)088 e-Print: arXiv:1111.2854 [hep-ph] We consider the gluon fusion production cross section of a scalar Higgs boson at NLO QCD in the SM and in the MSSM. We implement the calculation in the POWHEG approach, and match the NLO-QCD results with the PYTHIA and HERWIG QCD parton showers.