Graduate School in Physics and Astrophysics ------------------------------------------- ANNUAL REPORT ------------------------------------------- Fill with a text editor (without TAB or formatting) Repeat fields for each course as necessary. ------------------------------------------- name: GIOVANNI PELLICCIOLI email: gpellicc@unito.it, g.pelliccioli2@gmail.com ciclo: XXXII year completed (1,2 or 3): 2 supervisor: EZIO MAINA ------------------------------------------- CONFERENCES, WORKSHOP (only those attended in the current year) title: Monte-Carlo description of VBS place: NIKHEF, Amsterdam (Netherlands) webpage: https://indico.cern.ch/event/673764/ days: 2 (16-17 November 2017) talk or poster (Y/N): N title: VBSCAN mid-term meeting in the first grant period place: CERN, Genève (Swizerland) webpage: https://indico.cern.ch/event/689505/ days: 2 (7-8 February 2018) talk or poster (Y/N): N title: Subtracting Infrared Singularities Beyond NLO place: Higgs Center for Theoretical Physics, Edinburgh (UK) webpage: https://higgs.ph.ed.ac.uk/workshops/subtracting-infrared-singularities-beyond-nlo days: 4 (10-13 April 2018) talk or poster (Y/N): N title: 2nd VBSCan Annual Meeting place: University of Thessaloniki, Thessaloniki (Greece) webpage: https://indico.cern.ch/event/706178/ days: 3 (19-21 June 2018) talk or poster (Y/N): Y (talk) - POLARIZATIONS IN VBS AT THE LHC: WW, ZZ and WZ with PHANTOM ------------------------------------------- VISITS AND STAGES (only those done in the current year) institution: NIKHEF place: Amsterdam (Netherlands) starting date: 12 November 2017 days: 6 days ------------------------------------------- TEACHING ACTIVITY (only those done in the current year) course: "Elettricita' e Magnetismo", Bachelor Degree in Physics, Universita' di Torino year: 2017/18 teacher: Menichetti/Ferretti hours: 16 (tutorship) --------------------------------------------------- Research activity/Publications in the current year (max characters 2500) *Vector boson polarizations in VBS at the LHC This is the natural developement of the work performed during my first year. It concerns the extension of the polarization results obtained for W+W- scattering [1] to other scattering processes, in the fully leptonic decay channel. The results for polarized W+W+ at the LHC are very similar to those for W+W-. For scattering processes which involve Z bosons, the situation is more involved: using On-Shell projections for a gauge invariant treatment of resonant contributions is not enough to describe the full calculation. A sharp cut on the invariant mass of l+l- pairs around the Z pole mass is required to provide reasonable predictions: in this case, the separation of polarizations allows for realistic phenomenological studies, thanks to the partial (WZ) or complete (ZZ) knowledge of the four leptons system kinematics. *Precise Predictions for W+W+ scattering at the LHC The aim of this project [4] is to provide a comparison of the predictions for W+W+ scattering obtained with Monte Carlo generators capable of simulating VBS at leading order (LO) and next-to-leading order (NLO QCD). The comparison results in a good agreement between generators at LO and percent level differencies at NLO: discrepancies are due to the approximations employed in the various codes for the treatment of certain classes of diagrams. Also the matching of fixed-order predictions to parton-shower programs has been studied in detail. *Subtraction of infrared singularities at NNLO This project aims at finding a scheme for the subtraction of infrared divergencies in NNLO QCD computation. Starting from available NLO subtraction schemes, we retained the most advantageous features of each of them, discarded those features which would represent potential bottlenecks at NNLO, and built a new NLO scheme. Then we have extended it to NNLO: the result is a subtraction procedure which is local, general, analytical and efficient. We have validated the NLO subtraction scheme for the processes e+e- -> jj, H -> gg (comparison with MadGraph); concerning NNLO, we have checked that the TR CF contribution to the NNLO correction to e+e- -> jj, computed numerically with our scheme, agrees at the 0.1% level with the analytic results. This research is parallel to another one which is more formal [6]: driven by factorization properties of QCD amplitudes, we have provided a method to organize subtraction counterterms, valid at all orders in pertubation theory. [1] A.Ballestrero, E.Maina and G.Pelliccioli "W boson polarization in vector boson scattering at the LHC" JHEP03(2018)170 - http://inspirehep.net/record/1632481 - arXiv:1710.09339[hep-ph] [2] E.Maina, A.Ballestrero and G.Pelliccioli "W boson polarization in vector boson scattering at the LHC" PoS(EPS-HEP2017)451 - http://inspirehep.net/record/1666138 [3] C.F.Anders et al. "VBSCan Split 2017 Workshop Summary" http://inspirehep.net/record/1647952 - arXiv:1801.04203[hep-ph] [4] A.Ballestrero et al. "Precise predictions for same-sign W-boson scattering at the LHC" Eur.Phys.J. C78 (2018) no.8, 671 - http://inspirehep.net/record/1663469 - arXiv:1803.07943[hep-ph] [5] L.Magnea, E.Maina, G.Pelliccioli, C. Signorile-Signorile, P.Torrielli, S.Uccirati "Local Analytic Sector Subtraction at NNLO", accepted by JHEP https://inspirehep.net/record/1679581 - arXiv:1806.09570[hep-ph] [6] L.Magnea, E.Maina, G.Pelliccioli, C.Signorile-Signorile, P.Torrielli, S.Uccirati "Factorisation and Subtraction beyond NLO", submitted to JHEP https://inspirehep.net/record/1694278 - arXiv:1809.05444[hep-ph] BE AWARE: research activity and Pubs are not evaluated as didactic credits, but are requested to trace the PhD students' career