Combined ATLAS–CMS Higgs-pair searches reportedly constrain Higgs self-interaction

A science news account, sharing a Physical Review Letters post, describe the first combined ATLAS and CMS Higgs-pair searches at 13 TeV. It reports an observed signal strength of 0.8, with uncertainties of +0.9 and −0.7. The reported 95% confidence upper limit is 2.5 times the Standard Model prediction, compared with an expected limit of 1.7 times. The account also reports a constraint of −0.71 < κλ < 6.1 on the trilinear self-coupling modifier, a parameter describing Higgs self-interaction.