Download or read book Measurement of the Standard Model ZZ Cross Section in the ZZ to ell ell ell ell Channel written by and published by . This book was released on 2011 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we study one of the last corners of the Standard Model to be thoroughly investigated in a hadron collider, the production of two simultaneous Z bosons. We analyze 6.1 fb-1 of data produced at Fermilab at a center-of-mass energy √s = 1.96 TeV and recorded by the CDF experiment. The predicted cross-section is 1.4 pb and we measured 2.18+0.64 -0.63 pb (stat) 0:30 (syst) using 14 observed events. This is the largest set of candidate events in this channel yet found and with our estimated signal in the sample of 9.54 events provides the smallest percentage uncertainty on the ZZ cross-section to date. We also use this large set of events to yield kinematic plots and measure ZZ properties that will be of use in probing for new physics in the future.
Download or read book A Measurement of the WZ and ZZ Production Cross Sections Using Leptonic Final States in 8 6 Fb 1 of p bar p Collisions written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the processes p{bar p} → WZ → l?ll− and p{bar p} → ZZ → l+l−?{bar {nu}}, where l = e or?. Using 8.6 fb−1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron collider, we measure the WZ production cross section to be 4.50{sub -0.66}{sup +0.63} pb which is consistent with, but slightly above a prediction of the standard model. The ZZ cross section is measured to be 1.64 ± 0.46 pb, in agreement with a prediction of the standard model. Combination with an earlier analysis of the ZZ → l+l−l+l− channel yields a ZZ cross section of 1.44{sub -0.34}{sup +0.35} pb.
Download or read book Measurement of the ZZ Production Cross Section Using the Full CDF II Data Set written by and published by . This book was released on 2014 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the ZZ Production Cross Section and Limits on Anomalous Triple Gauge Couplings at s written by Rachel Hinman and published by . This book was released on 2012 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the ZZ Production Cross Section and Limits to the Anomalous Triple Gauge Couplings with Forward Electrons with the ATLAS Detector written by Deywis Moreno-Lopez and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the ZZ Production Cross Section in Pp u00AF Collisions at S written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present a new measurement of the production cross section ?(pp = ZZ) at a center-of-mass energy √s = 1.96 TeV, obtained from the analysis of the four charged lepton final state l+l-l+̀l-̀(l, l ̀= e or ?). They observe ten candidate events with an expected background of 0.37 ± 0.13 events. The measured cross section ?(pp =ZZ) = 1.26-0.37+0.47 (stat) ± 0.14 (syst) pb is in agreement with NLO QCD predictions. This result is combined with a previous result from the ZZ = l+l- ?? channel resulting in a combined cross section of ?(pp = ZZ) = 1.40-0.37-0.43 (stat) ±0.14 (syst) pb.
Download or read book Measurement of the ZZ Production Cross Section and Limits on Anomalous Neutral Triple Gauge Couplings with the ATLAS Detector written by Nicholas Charles Edwards and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Discovery of the Higgs Boson Measurements of Higgs Boson Properties and Search for High Mass Beyond the Standard Model Scalar Particle in the Diphoton Final State with the ATLAS Detector at the Large Hadron Collider written by Hongtao Yang and published by . This book was released on 2016 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: With 4.8~$\rm{fb}^{-1}$ of proton-proton collision data collected at $\sqrt{s}=7~\rm{TeV}$ in 2011, and 5.9~$\rm{fb}^{-1}$ collected at $\sqrt{s}=8~\rm{TeV}$ in 2012 by the ATLAS detector at the Large Hadron Collider, an excess of 4.5 standard deviations from the background-only hypothesis is observed near 126.5~GeV in the diphoton invariant mass spectra. Along with the excesses observed in the $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$ and $H \rightarrow WW^{(*)}\rightarrow \ell\nu\ell\nu$ channels, the observation of a Higgs-like particle is established at 6.0 standard deviations level. With more data accumulated during LHC Run~1, the measurements of Higgs boson couplings and mass in the $H\to\gamma\gamma$ channel are conducted by the ATLAS experiment based on 4.5~$\rm{fb}^{-1}$ of proton-proton collisions at $\sqrt{s}=7~\rm{TeV}$ collected in 2011, and 20.3~$\rm{fb}^{-1}$ at $\sqrt{s}=8~\rm{TeV}$ collected in 2012. The combined signal strength, defined as number of observed Higgs boson decays to diphoton divided by the corresponding Standard Model prediction, is measured to be $1.17 \ ^{+0.28}_{-0.26}$ assuming the Higgs boson mass being 125.4~$\rm{GeV}$. The signal strengths for individual Higgs boson production processes are also measured, and are found to be in good consistency with the Standard Model. The mass of the Higgs boson is measured in $H\to\gamma\gamma$ channel by the ATLAS experiment to be $125.98 \pm 0.50$~\GeV. This measurement is combined with the ones from ATLAS $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$ as well as CMS $H\to\gamma\gamma$ and $H \rightarrow ZZ^{(*)}\rightarrow \ell\ell\ell\ell$. The Higgs boson mass measured from the combination is $125.09\pm0.24~\rm{GeV}$. With LHC center-of-mass energy increased to 13~TeV, a search for high mass Beyond the Standard Model scalar resonance is performed in the diphoton decay channel based on 15.4~$\rm{fb}^{-1}$ of proton-proton collision data collected by the ATLAS detector during 2015 and 2016. While a notable wide excess was first observed in the diphoton invariant mass spectrum from the 2015 data (3.2~$\rm{fb}^{-1}$) with mass near 750~GeV, it is not confirmed by the 2016 data with much higher statistics (12.4~$\rm{fb}^{-1}$). Limits on the production cross section times branching ratio of such resonances are set.
Download or read book Z Cross section Measurement BR Z in the Electron Channel for P bar P Collisions at s written by and published by . This book was released on 1994 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Z +? cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF 1988--1989 collider run, for which the total integrated luminosity was 4.05 ± 0.28 pb−1. Two Z? candidates are observed from central photon events with?R/{sub?}> 0.7 and E{sub t}{sup?}> 5.0 GeV. From these events the? * BR(Z +?) is measured and compared with SM predictions:? * BR(Z +?){sub e} = 6.8{sub -5.7}{sup +5.7}(stat + syst)pb? * BR(Z + {gamma})SM = 4.7{sub -4.7}{sup +0.7}(stat + syst)pb. From this ZZ{sub {gamma}} cross section measurement limits on the Z{sub {gamma}{gamma}} and couplings for three different choices of compositeness scale?{sub Z} are obtained. The experimental sensitivity to the h30{sup Z, {gamma}}/h10{sup Z, {gamma}} couplings is in the range of?{sub Z} - 450--500 GeV and for the h40{sup Z{gamma}}/h20{sup Z, {gamma}} couplings?{sub Z} - 300 GeV.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for ZW ZZ to ell ell Jets Production in p bar p Collisions at CDF written by and published by . This book was released on 2012 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Standard Model of particle physics describes weak interactions mediated by massive gauge bosons that interact with each other in well-defined ways. Observations of the production and decay of WW, WZ, and ZZ boson pairs are an opportunity to check that these self-interactions agree with the Standard Model predictions. Furthermore, final states that include quarks are very similar to the most prominent final state of Higgs bosons produced in association with a W or Z boson. Diboson production where WW is a significant component has been observed at the Tevatron collider in semi-hadronic decay modes. We present a search for ZW and ZZ production in a final state containing two charged leptons and two jets using 8.9 fb-1 of data recorded with the CDF detector at the Tevatron. We select events by identifying those that contain two charged leptons, two hadronic jets, and low transverse missing energy (ET). We increase our acceptance by using a wide suite of high-pT lepton triggers and by relaxing many lepton identification requirements. We develop a new method for calculating corrections to jet energies based on whether the originating parton was a quark or gluon to improve the agreement between data and the Monte Carlo simulations used to model our diboson signal and dominant backgrounds. We also make use of neural-network-based discriminants that are trained to pick out jets originating from b quarks and light-flavor quarks, thereby increasing our sensitivity to Z 2!b$\bar{b}$ and W=Z 2!q$\bar{p'}$0 decays, respectively. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three channels: a heavy-flavor tagged channel, a light-flavor tagged channel, and an untagged channel. We measure [sigma]ZW/ZZ= 2.5+2.0 -1.0 pb, which is consistent with the SM cross section of 5.1 pb. We establish an upper limit on the cross section of [sigma]ZW/ZZ
Download or read book A measurement of the Z boson transverse momentum distribution and of the ZZ and WZ production cross sections using 7 3 8 6 fb 1 of pp collisions at s written by Mika Vesterinen and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wild gewild gevild written by and published by . This book was released on 1983 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Measurement of the Z Gamma Cross Section and Limits on Anomalous Triple Gauge Couplings at Square Root of S written by and published by . This book was released on 2012 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the properties of the Z$\gamma$ diboson system is presented using 5.0 fb$^{-1}$ of proton-proton collision data from the LHC using the CMS detector. The pp $\rightarrow Z(\rightarrow\mu \mu) \gamma$ and pp $\rightarrow Z(\rightarrow e e) \gamma$ production cross sections are measured within the fiducial volume of CMS with a combined measurement of $\sigma_{\ell\ell\gamma} = 5.33 \pm 0.08 ~\text{(stat.)} \pm 0.25 ~\text{(syst.)} \pm 0.12 ~\text{(lumi.)}$ pb that is in good agreement with Standard Model predictions. Upper limits on the neutral anomalous triple gauge couplings set are the most stringent limits on these couplings to date, with allowed regions: $-0.010
Download or read book A measurement of the Z Boson transverse momentum distribution and of the ZZ and WZ production cross sections using 7 3 8 6 fb 1 of p bar p Collisions at sqrt s written by Mika Vesterinen and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Standard Model Z e e Production Cross Section at s written by Sylwia Migas and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Standard Model Z ee Production Cross Section at s written by Sylwia Migas and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
