Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production

Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Del Valle, A. Escalante; Frühwirth, R.; Jeitler, M.; Krammer, N.; Lechner, L.; Liko, D.; Mikulec, I.; Paulitsch, P.; Pitters, F. M.; Schieck, J.; Schöfbeck, R.; Schwarz, D.; Templ, S.; Waltenberger, W.; Wulz, C. E.; Chekhovsky, V.; Litomin, A.; Makarenko, V.; Darwish, M. R.; De Wolf, E. A.; Janssen, T.; Kello, T.; Lelek, A.; Sfar, H. Rejeb; Van Mechelen, P.; Van Putte, S.; Van Remortel, N.; Bols, E. S.; D'Hondt, J.; De Moor, A.; Delcourt, M.; El Faham, H.; Lowette, S.; Moortgat, S.; Morton, A.; Müller, D.; Sahasransu, A. R.; Tavernier, S.; Van Doninck, W.; Vannerom, D.; Beghin, D.; Bilin, B.; Clerbaux, B.; De Lentdecker, G.; Favart, L.; Kalsi, A. K.; Lee, K.; Mahdavikhorrami, M.; Makarenko, I.; Paredes, S.; Pétré, L.; Popov, A.; Postiau, N.; Starling, E.; Thomas, L.; Bemden, M. Vanden; Vander Velde, C.; Vanlaer, P.; Cornelis, T.; Dobur, D.; Knolle, J.; Lambrecht, L.; Mestdach, G.; Niedziela, M.; Rendón, C.; Roskas, C.; Samalan, A.; Skovpen, K.; Tytgat, M.; Van Den Bossche, N.; Vermassen, B.; Wezenbeek, L.; Benecke, A.; Bethani, A.; Bruno, G.; Bury, F.; Caputo, C.; David, P.; Delaere, C.; Donertas, I. S.; Giammanco, A.; Jaffel, K.; Jain, Sa; Lemaitre, V.; Mondal, K.; Prisciandaro, J.; Taliercio, A.; Teklishyn, M.; Tran, T. T.; Vischia, P.; Wertz, S.; Alves, G. A.; Hensel, C.; Moscatelli, F.; Asenov, P.

doi:10.1038/s41567-022-01682-0

Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width--related to its lifetime--is an important parameter. One way to determine this quantity is to measure its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here we report evidence for such off-shell contributions to the production cross-section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at the 95% confidence level. The scenario with no off-shell contribution is excluded at a p-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as ?H=3.2-1.7+2.4MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs.