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CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-9493
DTSTART:20251205T173000Z
DTEND:20251205T193000Z
DTSTAMP:20260413T120342Z
LAST-MODIFIED:20251113T201645Z
LOCATION:5280 Chamberlin
SUMMARY:Study of ZZ+jets and Electroweak ZZ+2jets Production in Proton
 -Proton Collisions at √s = 13 TeV in Four-Lepton Events Using the CM
 S Detector at the LHC\, Thesis Defense\, He He\, Physics PhD Graduate 
 Student
DESCRIPTION:Two studies are presented on di-boson production in associ
 ation with jets in the fully leptonic final states\, pp → (Z/γ∗)(
 Z/γ∗) + jets → 2ℓ2ℓ′ + jets\, (ℓ\, ℓ′ = e or μ) in p
 roton-proton collisions at a center-of-mass energy of 13 TeV. The data
  sample corresponds to an integrated luminosity of 138 fb−1 collecte
 d with the CMS detector at the LHC. In the first study\, search is per
 formed for the electroweak (EW) production of two Z bosons in associat
 ion with two jets (EW ZZ+2jets) using a deep neural network (DNN) appr
 oach\, and the production is measured with an observed (expected) sign
 ificance of 4.4 (3.4) standard deviations\, consistent with the publis
 hed CMS results based on a matrix element likelihood approach (MELA). 
 In the second study\, differential distributions and normalized differ
 ential cross sections of di-boson ZZ production associated with differ
 ent numbers of jets (ZZ+jets) are measured as a function of jet multip
 licity\, transverse momentum pT\, pseudorapidity η\, invariant mass a
 nd ∆η of the highest-pT and second-highest-pT jets\, and as a funct
 ion of invariant mass of the four-lepton system for events with variou
 s jet multiplicities. These differential cross sections are compared w
 ith theoretical predictions that mostly agree with the experimental da
 ta. However\, in a few regions we observe discrepancies between the pr
 edicted and measured values. Further improvement of the predictions is
  required to describe the ZZ+jets production in the whole phase space.
URL:https://www.physics.wisc.edu/events/?id=9493
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