Leptoquarks are exotic particles that have color, electric charge, and lepton number and appear in extended gauge theories and composite models. Current theory suggests that leptoquarks would come in ...three different generations corresponding to the three quark and lepton generations. We are searching for charge 1/3 third generation leptoquarks produced in pp¯ collisions at special characters omitted=1.96 TeV using data collected by the DO detector. Such leptoquarks would decay into either a tauneutrino plus a b-quark or, if heavy enough, to a tau-lepton plus a t-quark. We present preliminary results on an analysis where both leptoquarks decay into neutrinos, giving a final state with missing energy and two b-quarks using 367 pb-1 of Run II DØ data taken between August 2002 and September 2004. We place upper limits on σ(pp¯ →, LQ LQ)B2 as a function of the leptoquark mass MLQ. Assuming B = 1, we exclude at the 95% confidence level third generation leptoquarks with MLQ < 197 GeV/c2. N
We report on D0 searches for leptoquarks (LQ) predicted in extended gauge theories and composite models to explain the symmetry between quarks and leptons. Data samples obtained with the D0 detector ...from proton-antiproton collisions at a center-of-mass energy of 1.96 TeV corresponding to intergrated luminosities of 1--4 inverse-fb were analyzed. No evidence for the production of such particles were observed and lower limits on leptoquark masses are set.
We report on D0 searches for scalar quarks (tilde-q) and gluinos (tilde-g), the superpartners of quark and gluons, in topologies involving jets and missing transverse energies. Data samples obtained ...with D0 detector from proton anti-proton collisions at a center-of-mass energy of 1.96 TeV corresponding to an intergrated luminosities of 1-4 inverse-fb were analyzed. No evidence for the production of such particles were observed and lower limits on squarks and gluino masses were set.
Photoelectron yields of extruded scintillation counters with titanium dioxide coating and embedded wavelength shifting fibers read out by silicon photomultipliers have been measured at the Fermilab ...Test Beam Facility using 120\,GeV protons. The yields were measured as a function of transverse, longitudinal, and angular positions for a variety of scintillator compositions and reflective coating mixtures, fiber diameters, and photosensor sizes. Timing performance was also studied. These studies were carried out by the Cosmic Ray Veto Group of the Mu2e collaboration as part of their R\&D program.
We present a measurement of the effective weak mixing angle parameter $\sin^2\theta_\text{eff}^{\ell}$, in $p\bar{p}\rightarrow Z/\gamma^* \rightarrow \mu^+\mu^-$ events at a center of mass energy of ...1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider and corresponding to 8.6 fb$^{-1}$ of integrated luminosity. The measured value of $\sin^2\theta_\text{eff}^{\ell}\mu\mu=0.23016 \pm 0.00064$ is further combined with the result from the D0 measurement in $p\bar{p}\rightarrow Z/\gamma^{*}\rightarrow e^{+} e^{-}$ events, resulting in $\sin^2\theta_\text{eff}^{\ell} \text{comb.}=0.23095 \pm 0.00040$. This combined result is the most precise measurement from a single experiment at a hadron collider and is the most precise determination using the coupling of the $Z/\gamma^*$ to light quarks.
