### Session E7: Electroweak Physics with W's and Z's

 Saturday, April 16, 2005 3:30PM - 3:54PM E7.00001: Study of Z$\gamma$ production Yurii Maravin We present a measurement of the Z$\gamma$ production cross-section and limits on CP-conserving anomalous ZZ$^*\gamma$ and Z$\gamma^*\gamma$ couplings for form-factor scales of $\Lambda$ = 750 and 1000 GeV. We collected 138 (152) candidate events in the ee$\gamma$ ($\mu\mu\gamma$) final states using 324 (286) pb$^{-1}$ of p$\bar{\rm p}$ collisions at $\sqrt{s}$ = 1.96 TeV. 95\% C.L. limits on individual anomalous couplings are $|h^Z_{30}| < 0.21$, $|h^{\gamma}_{30}| < 0.22$, and $|h^{\gamma, {\rm Z}}_40| < 0.019$ for $\Lambda$ = 1000 GeV. Saturday, April 16, 2005 3:54PM - 4:06PM E7.00002: Search at D\O\ for Inclusive $WZ$ Diboson Events in Trilepton Final States at $\sqrt(s)=1.96$ TeV James Degenhardt Presented is a study of searching for $WZ$ diboson events in trilepton final states using data on $p\bar{p}$ collision collected by the D\O\ experiment during 2002-2004 at the Fermilab Tevatron at a center-of-mass energy of 1.96 {\rm TeV}. The cleanest experimental signal for the $WZ$ events is from a pair of leptons ($e^+e^-$ or $\mu^+\mu^-$) from the decay of the Z boson, and another lepton ($e$ or $\mu$) with large transverse momentum ($p_T$) and a large imbalance $p_T$ in the event (missing neutrino) from the leptonic decay of the W boson. Three trilepton events with the $WZ$ decay characteristics is observed in D\O\ data. With an estimated background of $0.66\pm 0.11$ events and integrated luminosities ranging from 285 - 320 ${\rm pb}^{-1}$ for different trilepton final states, we measure the $WZ$ production cross section to be $4.4^{+3.8}_{-2.5}$~{\rm pb} and set a 95\% confidence level upper limit of $13.2$~{\rm pb}. We also obtain 95\% confidence limit contours for $\lambda_Z$ vs.$\Delta g_1^Z$ and $\Delta\kappa_Z$ vs.$\lambda_Z$ using a form factor of $\Lambda = 1$~{\rm TeV}. Saturday, April 16, 2005 4:06PM - 4:18PM E7.00003: A Limit on WW+WZ Boson Production in the Lepton + MET + Jets Decay Channel Jorgen Sjolin We study WW+WZ production in the lepton + missing tranvserse energy + jets channel at the Tevatron Run II using about 200 pb$^{-1}$ of CDF data. An upper limit on the cross-section for WW+WZ production is derived and kinematic distributions are compared to Standard Model predictions. The method for estimating the number of signal events uses the deviation in shape between the measured jet-jet invariant mass and the expected background in order to avoid a strong dependence on the absolute background normalization. Saturday, April 16, 2005 4:18PM - 4:30PM E7.00004: Measurement of the forward--backward asymmetry of muons coming from the decay of $W$ bosons with the D\O\ Detector Sinjini Sengupta We present a measurement of the forward--backward asymmetry of muons coming from the decay of $W$ bosons produced in $p\bar{p}$ collisions at $\sqrt{s} =$1.96 TeV collected with the D\O\ Detector at Fermilab. We discuss the prospects for using the asymmetry to constrain the ratio of $d$ and $u$ quark momentum distributions in the proton. Saturday, April 16, 2005 4:30PM - 4:42PM E7.00005: A New Method for Determining the W Production Charge Asymmetry Boyoung Han We present a new analysis method which directly reconstructs the $W$ charge asymmetry using $W^{\pm} \rightarrow e^{\pm} \nu$ decays at the Collider Detector at Fermilab. The $W$ mass constrains the unknown longitudinal momentum of the neutrino from the $W$ decay, leaving two possible $W$ rapidity solutions. We determine the relative contributions of the two solutions for each event according to the V-A decay structure of the weak interactions, resulting in a determination of the $W$ boson rapidity spectrum. Saturday, April 16, 2005 4:42PM - 4:54PM E7.00006: A New Method to Measure the Ratio of W and Z Cross Sections Katherine Copic , Victoria Martin , Michael Schmitt We present a new method for the measurement of the ratio, $R$, of cross sections for~$W$ and~$Z$ production in $p\bar{p}$~collisions at the Fermilab Tevatron. The leptonic signals from~$W$ and~$Z$ decays are treated in a strictly parallel fashion, and the~$p_T$ spectrum of the lepton is used to infer their relative rates. A preliminary measurement has been obtained from data collected with the CDF~II detector corresponding to approximately $350$~pb$^{-1}$. Using this value for~$R$ we extract a value for the width of the $W$~boson. Saturday, April 16, 2005 4:54PM - 5:06PM E7.00007: Event Generation for the Run 2 W Mass Measurement Ian Vollrath An important contribution to the systematic uncertainty on the Run II W mass measurement comes from the modelling of W boson production and decay. This source of uncertainty will be one of the most significant in future high-statistics measurements. We describe the event generation used for constructing templates for fitting the W mass, including the relevant physics processes influencing the lineshapes of the fit variables. We present systematic uncertainties deriving from the production model, including final state photon radiation and $p_{T}^{W}$.