Search for gluinos and squarks using like-sign dileptons in pp macro collisions at square root of s = 1.8 TeV.
Phys Rev Lett 87:25 (2001) 251803
Abstract:
We present results of the first search for like-sign dilepton ( e(+/-)e(+/-), e(+/-)mu(+/-), mu(+/-)mu(+/-)) events associated with multijets and large missing energy using 106 pb(-1) of data in pp macro collisions at square root of s = 1.8 TeV collected during 1992-1995 by the CDF experiment. Finding no events that pass our selection, we examine pair production of gluinos (tilde g) and squarks (tilde q) in a constrained framework of the minimal supersymmetric standard model. At tan beta = 2 and mu = -800 GeV/c(2), we set 95% confidence level limits of M(tilde g)>221 GeV/c(2) for M(tilde g) approximately M(tilde q), and M(tilde q)>168 GeV/c(2) for M(tilde q)>>M(tilde g), both with small variation as a function of mu.Observation of diffractive J/psi production at the Fermilab Tevatron.
Phys Rev Lett 87:24 (2001) 241802
Abstract:
We report the first observation of diffractive J/psi(--> mu+mu-) production in pp collisions at root square[s] = 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p(mu)T>2 GeV/c within the pseudorapidity region /eta/ < 1.0, the ratio of diffractive to total J/psi production rates is found to be R(J/psi) = [1.45 +/- 0.25]%. The ratio R(J/psi)(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio R(jj)(x) for diffractive dijet production, we extract a value of 0.59 +/- 0.15 for the gluon fraction of the diffractive structure function of the proton.Search for new physics using QUAERO: A general interface to D0 Event data
Physical Review Letters 87:23 (2001) 2318011-2318016
Abstract:
A method called QUAERO, for automatic optimization of searches for physics beyond the standard model is presented. The method provides a mechanism that allows the availability of high energy collider data. The algorithms used in QUAERO and the final states available for analysis are described. Results showed that the limits obtained on application of the method to standard model and resonant production are comparable to those from previous searches at hadron colliders.Search for new physics using QUAERO: a general interface to D0 event data.
Phys Rev Lett 87:23 (2001) 231801
Abstract:
We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ, and t t macro production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W'-->WZ. Through this interface, we make three data sets collected by the D0 experiment at square root of [s] = 1.8 TeV publicly available.Search for quark-lepton compositeness and a heavy W' Boson using the enu channel in p p macro collisions at square root of [s] = 1.8 TeV.
Phys Rev Lett 87:23 (2001) 231803