Measurements of the polarization and spin correlation in top quark pairs (tt¯) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at √s = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb−1. All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the tt¯ system and the top quark scattering angle in the tt¯ rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the tt¯ spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for tt¯ states at the production threshold and at high masses of the tt¯ system. Entanglement is observed for the first time in events at high tt¯ mass, where a large fraction of the tt¯ decays are space-like separated, with an expected and observed significance of above 5 standard deviations.

Hayrapetyan, A., Tumasyan, A., Adam, W., Andrejkovic, J. ., Benato, L., Bergauer, T., et al. (2024). Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using lepton+jets events from proton-proton collisions at √s = 13 TeV. PHYSICAL REVIEW D, 110(11), 1-49 [10.1103/physrevd.110.112016].

Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using lepton+jets events from proton-proton collisions at √s = 13 TeV

Battilana, C.;Bonacorsi, D.;Capiluppi, P.;Castro, A.;Cuffiani, M.;Diotalevi, T.;Fanfani, A.;Fasanella, D.;Giommi, L.;Guiducci, L.;Lorusso, M.;Navarria, F.  L.;Paggi, G.;Rossi, A.  M.;Rossi Tisbeni, S.;Rovelli, T.;Siroli, G.  P.;
2024

Abstract

Measurements of the polarization and spin correlation in top quark pairs (tt¯) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at √s = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb−1. All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the tt¯ system and the top quark scattering angle in the tt¯ rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the tt¯ spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for tt¯ states at the production threshold and at high masses of the tt¯ system. Entanglement is observed for the first time in events at high tt¯ mass, where a large fraction of the tt¯ decays are space-like separated, with an expected and observed significance of above 5 standard deviations.
2024
Hayrapetyan, A., Tumasyan, A., Adam, W., Andrejkovic, J. ., Benato, L., Bergauer, T., et al. (2024). Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using lepton+jets events from proton-proton collisions at √s = 13 TeV. PHYSICAL REVIEW D, 110(11), 1-49 [10.1103/physrevd.110.112016].
Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J.  W.; Benato, L.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Hussain, P.  S....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1003111
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