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oai:www.ideals.illinois.edu:2142/22948 2023-07-10 col_2142_5131 col_2142_8859 com_2142_5130 com_2142_8858 com_2142_234

Errede, Steven M. Luchini, Christopher B. 2011-05-07T13:56:53Z 2011-05-07T13:56:53Z 10000-01-01 1994 We have measured the production cross sections x decay branching ratios for W + $\gamma$ and Z + $\gamma$ in the muon channel in $\sqrt{s}$ = 1.8 TeV p-p collisions, from 3.54 $\pm$ 0.24 $pb\sp{-1}$ of muon W and Z data from the CDF 1988-89 Tevatron collider run. For photons in the central region ($\vert\eta\vert $ 5.0 GeV and lepton-photon angular separation $\Delta R\sb{\ell\sb\gamma} >$ 0.7, 5 $W\sb{\gamma}$ candidates and 2 $Z\sb{\gamma}$ candidates were observed. From these events, the $\sigma \cdot BR(W + \gamma)$ and $\sigma \cdot BR(Z + \gamma)$ cross sections for the muon samples are measured, and compared with Standard Model predictions. We also determined the cross section ratios, $W\sb{\gamma}$/W, $Z\sb{\gamma}$/Z and $W\sb{\gamma}/Z\sb{\gamma}$, which, along with the previous CDF measurement(s) of the W/Z cross section ratio provide new insight on the Standard Model, and are sensitive to anomalous couplings of the W and Z bosons. Using the $W\sb{\gamma}$ and $Z\sb{\gamma}$ absolute cross section measurements, the absence of an excess of hard photons accompanying W and Z boson production enables us to obtain direct limites on anomalous $WW\sb{\gamma}$, $ZZ\sb{\gamma}$ and $Z\sb{\gamma\gamma}$ couplings. For saturation of unitarity, these experimental limits impose constraints on possible internal (composite) structure for the W and Z bosons with compositeness scale sensitivity up to $\Lambda\sb{W} \sim$ 1 TeV and $\Lambda\sb{Z} \sim$ 250-500 GeV, respectively. These compositeness scale limits probe the possible internal structure of the W to ${\sim}<$2 $\times$ 10$\sp{-4}$fm and internal structure of the Z to ${\sim}<$4-7 $\times$ 10$\sp{-4}$ fm. Limits on the anomalous $W\sb{\gamma}$ and $Z\sb{\gamma}$ couplings also impose constraints on the higher order static and transition EM moments of the W and Z boson, respectively. The muon channel measurements were combined with those made from the electron channel to arrive at $\mu$ + e combined $\sigma \cdot$ BR(W) + $\gamma$) and $\sigma \cdot$ BR(Z + $\gamma$) absolute cross sections, and limits on the anomalous couplings for combined $\mu$ + e $W\sb{\gamma}$ and $Z\sb{\gamma}$. Made available in DSpace on 2011-05-07T13:56:53Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9503260.pdf: 4824344 bytes, checksum: e397b9d399b0b95fdf247b9ed5ab735a (MD5) Previous issue date: 1994 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:07Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:28:59-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9503260 (UMI)AAI9503260 http://hdl.handle.net/2142/22948 eng Copyright 1994 Luchini, Christopher B. Physics, Elementary Particles and High Energy A measurement of W boson-photon and Z boson-photon cross sections in the muon channel in 1.8 TeV proton-antiproton collisions text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.