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Register a new userEvidence for hadronic deconfinement in $bar{p}$-p collisions at 1.8 TeV
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We have measured deconfined hadronic volumes, $4.4 < V < 13.0$ fm$^{3}$, produced by a one dimensional (1D) expansion. These volumes are directly proportional to the charged particle pseudorapidity densities $6.75 < dN_{c}/deta < 20.2$. The hadronization temperature is $T = 179.5 pm 5$ (syst) MeV. Using Bjorkens 1D model,the hadronization energy density is $epsilon_{F} = 1.10 pm 0.26$ (stat) GeV/fm$^{3}$ corresponding to an excitation of $24.8 pm 6.2$ (stat) quark-gluon degrees of freedom.
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It is shown that de-confinement can be achieved in high multiplicity non jet $bar{p}$p collisions at $sqrt{s}$= 1.8 TeV Fermi National Accelerator Laboratory(FNAL- E735) experiment. Previously the evidence for de-confinement was the demonstrated by the constant freeze out energy density in high multiplicity events. In this paper we use the same data but analyze the transverse momentum spectrum in the framework of the clustering of color sources. The charged particle pseudorapidities densities in the range 7.0 $leq langle dN_{c}/deta rangle leq$26.0 are considered. Results are presented for both thermodynamic and transport properties. The initial temperature and energy density are obtained and compared with the Lattice Quantum Chromo Dynamics(LQCD) simulations. The energy density ($varepsilon/T^{4}$) $sim$ 11.5 for $ langle dN_{c}/deta rangle sim $ 25.0 is close to the value for 0-10% central events in Au+Au collisions at $sqrt{s_{NN}}$= 200 GeV. The shear viscosity to entropy density ratio($eta/s$) is $sim$ 0.2 at the transition temperature. The result for the trace anomaly $Delta$ is in excellent agreement with LQCD simulations. These results confirm our earlier observation that the de-confined state of matter was created in high multiplicity events in $bar{p}$p collisions at $sqrt{s}$=1.8 TeV.
We report on a search for pair production of first-generation scalar leptoquarks ($LQ$) in $p bar{p}$ collisions at $sqrt{s}$=1.96 TeV using an integrated luminosity of 203 $pb^{-1}$ collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for $LQ$ production in the topologies arising from $LQ bar{LQ} to eqeq$ and $LQ bar{LQ} to eq u q$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as a function of $beta$, where $beta$ is the branching fraction for $LQ to eq$. The results are combined with those obtained from a separately reported CDF search in the topology arising from $LQbar{LQ} to u q u q$ and 95% C.L. lower limits on the LQ mass as a function of $beta = BR(LQ to eq) $ are derived. The limits are 236, 205 and 145 GeV/c$^2$ for $beta$ = 1, $beta$ = 0.5 and $beta$ = 0.1, respectively.
We search for high-mass resonances decaying into Z boson pairs using data corresponding to 6 fb^-1 collected by the CDF experiment in pbar{p} collisions at sqrt{s}=1.96 TeV. The search is performed in three distinct final states: ZZ --> l^+l^-l^+l^-, ZZ --> l^+l^- u u, and ZZ --> l^+l^-jj. For a Randall-Sundrum graviton G*, the 95% CL upper limits on the production cross section times branching ratio to ZZ, sigma(pbar{p} --> G^* --> ZZ), vary between 0.26 pb and 0.045 pb in the mass range 300 < M_{G*} < 1000 GeV/c^2.
We present the results of a search in pbar-p collisions at root-s=1.8 TeV for anomalous production of events containing a photon and a lepton (e or mu), both with large transverse energy, using 86 pb-1 of data collected with the Collider Detector at Fermilab during the 1994-95 collider run at the Fermilab Tevatron. The presence of large missing transverse energy, additional photons, or additional leptons in these events is also analyzed. The results are consistent with standard model expectations, with the possible exception of photon-lepton events with large missing transverse energy, for which the observed total is 16 events and the expected mean total is 7.6 pm 0.7 events.
This Letter describes the current most precise measurement of the $WZ$ production cross section as well as limits on anomalous $WWZ$ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions for the Collider Detector at Fermilab (CDF). $WZ$ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb$^{-1}$ of integrated luminosity), 63 candidate events are observed with the expected background contributing $8 pm 1$ events. The measured total cross section $sigma (p bar p to WZ) = 3.93_{-0.53}^{+0.60}(text{stat})_{-0.46}^{+0.59}(text{syst}) $ pb is in good agreement with the standard model prediction of $3.50pm 0.21$. The same sample is used to set limits on anomalous $WWZ$ couplings.
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