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001-es BibID:	BIBFORM119079
035-os BibID:	(Scopus)85140310896 (WoS)000870649900005
Első szerző:	CMS Collaboration
Cím:	Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production / CMS Collaboration
Dátum:	2022
ISSN:	1745-2473
Megjegyzések:	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 [gamma]_H=3.2_{-1.7}^{+2.4}MeV, 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.
Tárgyszavak:	Természettudományok Fizikai tudományok magyar nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Nature Physics. - 18 : 11 (2022), p. 1-30. -
További szerzők:	Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM116679
035-os BibID:	(Scopus)85162051065 (WoS)000927936700008
Első szerző:	CMS Collaboration
Cím:	Observation of triple J/[psi] meson production in proton-proton collisions / CMS Collaboration
Dátum:	2023
ISSN:	1745-2473
Megjegyzések:	Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering - referred to as single-parton scattering - leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/[psi] mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process - reconstructed through the decays of J/[psi] mesons into pairs of oppositely charged muons - with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be 272^{-104}_{+141} (stat) +/- 17 (syst) fb, and compared it to theoretical expectations for triple-J/[psi] meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Hadrons
Megjelenés:	Nature Physics. - 19 : 3 (2023), p. 338-350. -
További szerzők:	Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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