Search for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 Production via Trilepton Final States in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV

We have searched for associated production of the lightest chargino, $\widetilde{W}_1$, and next-to-lightest neutralino, $\widetilde{Z}_2$, of the Minimal Supersymmetric Standard Model in $p\bar{p}$ collisions at \mbox{$\sqrt{s}$ = 1.8 TeV} using the \D0 detector at the Fermilab Tevatron collider. Data corresponding to an integrated luminosity of 12.5$\pm 0.7$ \ipb were examined for events containing three isolated leptons. No evidence for $\widetilde{W}_1\widetilde{Z}_2$ pair production was found. Limits on $\sigma(\widetilde{W}_1\widetilde{Z}_2)$Br$(\widetilde{W}_1\to l\nu\widetilde{Z}_1)$Br$(\widetilde{Z}_2\to l\bar{l}\widetilde{Z}_1)$ are presented.Comment: 17 pages (13 + 1 page table + 3 pages figures). 3 PostScript figures will follow in a UUEncoded, gzip'd, tar file. Text in LaTex format. Submitted to Physical Review Letters. Replace comments - Had to resumbmit version with EPSF directive

Measurement of the WW Boson Mass

A measurement of the mass of the $W$ boson is presented based on a sample of 5982 $W \rightarrow e \nu$ decays observed in $p\overline{p}$ collisions at $\sqrt{s}$ = 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a fit to the transverse mass spectrum, combined with measurements of the $Z$ boson mass, the $W$ boson mass is measured to be $M_W = 80.350 \pm 0.140 (stat.) \pm 0.165 (syst.) \pm 0.160 (scale) GeV/c^2$.Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures (submitted to PRL

Second Generation Leptoquark Search in p\bar{p} Collisions at s\sqrt{s} = 1.8 TeV

We report on a search for second generation leptoquarks with the D\O\ detector at the Fermilab Tevatron $p\bar{p}$ collider at $\sqrt{s}$ = 1.8 TeV. This search is based on 12.7 pb$^{-1}$ of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio $\beta$ or to neutrino and quark with branching ratio $(1-\beta)$. We obtain cross section times branching ratio limits as a function of leptoquark mass and set a lower limit on the leptoquark mass of 111 GeV/c$^{2}$ for $\beta = 1$ and 89 GeV/c$^{2}$ for $\beta = 0.5$ at the 95%\ confidence level.Comment: 18 pages, FERMILAB-PUB-95/185-

The Azimuthal Decorrelation of Jets Widely Separated in Rapidity

This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the D{\O}detector during the 1992--1993 collider run of the Fermilab Tevatron at $\sqrt{s}=$ 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading--log approximations (LLA) where the leading--log terms are resummed to all orders in $\alpha_{\scriptscriptstyle S}$. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo {\small HERWIG} describes the data well; an analytical LLA prediction based on BFKL resummation shows more decorrelation than the data.Comment: 6 pages with 4 figures, all uuencoded and gzippe

Jet Production via Strongly-Interacting Color-Singlet Exchange in ppˉp\bar{p} Collisions

A study of the particle multiplicity between jets with large rapidity separation has been performed using the D{\O}detector at the Fermilab Tevatron $p\bar{p}$ Collider operating at $\sqrt{s}=1.8$ TeV. A significant excess of low-multiplicity events is observed above the expectation for color-exchange processes. The measured fractional excess is $1.07 \pm 0.10({\rm stat})^{+ 0.25}_{- 0.13}({\rm syst})$, which is consistent with a strongly-interacting color-singlet (colorless) exchange process and cannot be explained by electroweak exchange alone. A lower limit of 0.80% (95% C.L.) is obtained on the fraction of dijet events with color-singlet exchange, independent of the rapidity gap survival probability.Comment: 15 pages (REVTeX), 3 PS figs (uuencoded/tar compressed, epsf.sty) Complete postscript available at http://d0sgi0.fnal.gov/d0pubs/journals.html Submitted to Physical Review Letter

The Anti-Apoptotic Activity of BAG3 Is Restricted by Caspases and the Proteasome

Caspase-mediated cleavage and proteasomal degradation of ubiquitinated proteins are two independent mechanisms for the regulation of protein stability and cellular function. We previously reported BAG3 overexpression protected ubiquitinated clients, such as AKT, from proteasomal degradation and conferred cytoprotection against heat shock. We hypothesized that the BAG3 protein is regulated by proteolysis. caspase-resistant mutant. Caspase and proteasome inhibition resulted in partial and independent protection of BAG3 whereas inhibitors of both blocked BAG3 degradation. STS-induced apoptosis was increased when BAG3 was silenced, and retention of BAG3 was associated with cytoprotection.BAG3 is tightly controlled by selective degradation during STS exposure. Loss of BAG3 under STS injury required sequential caspase cleavage followed by polyubiquitination and proteasomal degradation. The need for dual regulation of BAG3 in apoptosis suggests a key role for BAG3 in cancer cell resistance to apoptosis

The Isolated Photon Cross Section in the Central and Forward Rapidity Regions in p-pbar Collisions at sqrt(s) = 1.8 TeV

A measurement of the cross section for production of single, isolated photons is reported for transverse energies in the range of 10-125 GeV, for two regions of pseudorapidity, |\eta|<0.9 and 1.6<|\eta|<2.5. The data represent 12.9 pb-1 of integrated luminosity accumulated in p-pbar collisions at sqrt{s} = 1.8 TeV and recorded with the D0 detector at the Fermilab Tevatron Collider.Comment: 9 pages, submitted to Physical Review Letters, http://d0sgi0.fnal.gov/~womersle/photon_prl_preprint.p

Measurement of the WWγWW\gamma gauge boson couplings in ppˉp\bar{p} Collisions at s=1.8\sqrt{s}=1.8 TeV

The $WW\gamma$ gauge boson couplings were measured using $p\bar{p}\to \ell\nu\gamma+X$ ($\ell=e,\mu$) events at $\sqrt{s}=1.8$ TeV observed with the {D\O} detector at the Fermilab Tevatron Collider. The signal, obtained from the data corresponding to an integrated luminosity of $13.8 {\rm pb}^{-1}$, agrees well with the Standard Model prediction. A fit to the photon transverse energy spectrum yields limits at the 95% confidence level on the CP--conserving anomalous coupling parameters of $-1.6<\Delta\kappa<1.8$ ($\lambda$ = 0) and $-0.6<\lambda<0.6$ ($\Delta\kappa$ = 0).Comment: 16pages (14pages + 2figure pages) Uses ReVTEX Two postscript files for figures will follow immediatel

Search for Right-Handed WW Bosons and Heavy W′W^\prime in ppˉp\bar p Collisions at s=\sqrt{s} =1.8 TeV

We report on a search for right-handed $W$ bosons ($W_R$). We used data collected with the D{\O} detector at the Fermilab Tevatron $p\bar p$ collider at $\sqrt{s}=$1.8 TeV to search for $W_R$ decays into an electron and a massive right-handed neutrino $W_R^\pm \to e^\pm N_R$. Using the inclusive electron data, we set mass limits independent of the $N_R$ decay: $m_{W_R}>650$ GeV/c$^2$ and $m_{W_R}>720$ GeV/c$^2$ at the 95% confidence level, valid for $m_{N_R}<{1/2}m_{W_R}$ and $m_{N_R} \ll m_{W_R}$ respectively. The latter also represents a new lower limit on the mass of a heavy left-handed $W$ boson ($W^\prime$) decaying into $e \nu$. In addition, limits on $m_{W_R}$ valid for larger values of the $N_R$ mass are obtained assuming that $N_R$ decays to an electron and two jets.Comment: 15 pages, 5 figures (in UUencoded postscript file which will follow) uses preprint,epsf,eqsecnum,aps,floats,revtex Submitted to Physical Review Letter