CDF Logo Observation of Z0 Z0 &rarr 4 lepton at CDF
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Authors: Matteo Bauce, Simone Pagan Griso, Donatella Lucchesi, Doug Benjamin, Mark Kruse,Eric James, Sergo Jindariani,
Britney Rutherford, Roman Lysak, Dean Andrew Hidas, Aidan Robson, Rick St.~Denis, Peter Bussey,Matthew Herndon, Jennifer Pursley

Contacts: Matteo Bauce, Simone Pagan Griso and Donatella Lucchesi


The Z0 Z0 cross section measurement is important to test Standard Model predictions of Electro-Weak couplings. In addition the Z0 Z0 reconstruction is the first step for Higgs searches in the high mass region. In 1.9fb -1 of data CDF has observed a Z0 Z0 signal with a significance of 4.4σ when combining Z0 Z0 → lll'l' and the Z0 Z0 → llν ν decay channels. The search for Z0 Z0 &rarr lll'l' with 4.8 fb-1 of data and with an extended lepton coverage is presented here. The number of expected signal events is 4.68 ± 0.78, we observe 5 events with 4.15 ± 1.62(stat) ± 2.87(syst) × 10-2 background events, and this corresponds to a significance of 5.70 σ. This is the first observation of a ZZ signal using CDF data. With these events we measure a cross section of 1.56+0.80-0.63(stat) ± 0.25(syst), in agreement with Standard Model value 1.4 ±0.1 pb at Next to Leading Order.

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Link to the previous Z0 Z0 analysis

The results should be considered preliminary until published in a refereed journal. They can be used in conference presentations with proper reference to the CDF Collaboration.