Federico Ambrogi

Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton–proton collisions at √s=13TeV

A data sample of events from proton-proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9 fb−1, and a center-of-mass energy of 13 TeV. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associated production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500 GeV for gluinos, 830 GeV for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350–360 (350–410) GeV. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results. Published in the European Physical Journal C as doi:10.1140/epjc/s10052-017-5079-z. c

Search for resonant and nonresonant Higgs boson pair production in the b b ¯final state in proton-proton collisions at √s=13 TeV

Searches for resonant and nonresonant pair-produced Higgs bosons (HH) decaying respectively into lνlν, through either W or Z bosons, and bb¯¯¯ are presented. The analyses are based on a sample of proton-proton collisions at s√=13 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. Data and predictions from the standard model are in agreement within uncertainties. For the standard model HH hypothesis, the data exclude at 95% confidence level a product of the production cross section and branching fraction larger than 72 fb, corresponding to 79 times the standard model prediction. Constraints are placed on different scenarios considering anomalous couplings, which could affect the rate and kinematics of HH production. Upper limits at 95% confidence level are set on the production cross section of narrow-width spin-0 and spin-2 particles decaying to Higgs boson pairs, the latter produced with minimal gravity-like coupling.Searches for resonant and nonresonant pair-produced Higgs bosons (HH) decaying respectively into `ν`ν, through either W or Z bosons, and bb are presented. The analyses are based on a sample of proton-proton collisions at √ s = 13 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb−1. Data and predictions from the standard model are in agreement within uncertainties. For the standard model HH hypothesis, the data exclude at 95% confidence level a product of the production cross section and branching fraction larger than 72 fb, corresponding to 79 times the standard model prediction. Constraints are placed on different scenarios considering anomalous couplings, which could affect the rate and kinematics of HH production. Upper limits at 95% confidence level are set on the production cross section of narrow-width spin-0 and spin-2 particles decaying to Higgs boson pairs, the latter produced with minimal gravity-like coupling. Published in the Journal of High Energy Physics as doi:10.1007/JHEP01(2018)054. c