UMass team leads effort to measure the Higgs boson total width

A team led by Prof. Coelho Lopes de Sa, including Research Scientist William Leight, Postdocs Martina Javurkova and Michiel Veen, and Graduate Student Sam Krishnamurthy has produced first evidence for off-shell production of Higgs bosons. The analysis is based on 139 fb-1 of data collected with the ATLAS detector at the Large Hadron Collider during the years from 2015 to 2018. A sample of Higgs boson decays into pairs of Z bosons yielding final states with either 4 charged leptons (4l) or 2 charged leptons and 2 neutrinos (2l2v) was used to measure the off-shell Higgs production rate. A zero width is excluded for the first time with a significance greater than 3 standard deviations. The findings are summarized in a news item at https://atlas.cern/Updates/Briefing/Higgs-Total-Width and a complete description of the analysis is available as an ATLAS conference note.