arXiv subjects

B. Abbott et al

Publications and source records attributed to B. Abbott et al.

8 recordsLinked to original sources

arXiv1999

Search for Second Generation Leptoquark Pairs Decaying to μν+ jets in p-pbar Collisions at sqrt{s} = 1.8 TeV

We report on a search for second generation leptoquarks (LQ) produced in $p\bar{p}$ collisions at sqrt{s} = 1.8 TeV using the D0 detector at Fermilab. Second generation leptoquarks are assumed to be produced in pairs and to decay to either μor νand either a strange or a charm quark (q). Limits are placed on σ(p-pbar -> LQ-LQbar -> μν+ jets) as a function of the mass of the leptoquark. For equal branching ratios to μq and νq, second generation scalar leptoquarks with a mass below 160 GeV/c^2, vector leptoquarks with anomalous minimal vector couplings with a mass below 240 GeV/c^2, and vector leptoquarks with Yang-Mills couplings with a mass below 290 GeV/c^2, are excluded at the 95% confidence level.

hep-ex↗

arXiv1999

Search for Squarks and Gluinos in Events Containing Jets and a Large Imbalance in Transverse Energy

Using data corresponding to an integrated luminosity of 79 pb-1, D0 has searched for events containing multiple jets and large missing transverse energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos and on the model parameters m_0 and m_1/2, in the framework of the minimal low-energy supergravity models of supersymmetry. For tan(beta) = 2 and A_0 = 0, with mu < 0, we exclude all models with m_squark < 250 GeV/c^2. For models with equal squark and gluino masses, we exclude m < 260 GeV/c^2.

hep-ex↗

arXiv1998

Probing Hard Color-Singlet Exchange in ppbar Collisions at root-s=630 GeV and 1800 GeV

We present results on dijet production via hard color-singlet exchange in proton-antiproton collisions at root-s = 630 GeV and 1800 GeV using the DZero detector. The fraction of dijet events produced via color-singlet exchange is measured as a function of jet transverse energy, separation in pseudorapidity between the two highest transverse energy jets, and proton-antiproton center-of-mass energy. The results are consistent with a color-singlet fraction that increases with an increasing fraction of quark-initiated processes and inconsistent with two-gluon models for the hard color-singlet.

hep-ex↗

arXiv1998

Search For Heavy Pointlike Dirac Monopoles

We have searched for central production of a pair of photons with high transverse energies in $p\bar p$ collisions at $\sqrt{s} = 1.8$ TeV using $70 pb^{-1}$ of data collected with the DØdetector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of $610, 870, or 1580 GeV/c^2$ on the mass of a spin 0, 1/2, or 1 Dirac monopole.

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arXiv1998

Measurement of the Shape of the Transverse Momentum Distribution of W Bosons Produced in pbarp Collisions at sqrt(s)= 1.8 TeV

The shape of the transverse momentum distribution of W bosons (p_T(W)) produced in pbarp collisions at sqrt(s)= 1.8 TeV is measured with the DO detector at Fermilab. The result is compared to QCD perturbative and resummation calculations over the p_T(W) range from 0-200 GeV/c. The shape of the distribution is consistent with the theoretical prediction.

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arXiv1998

Search for the Decay b -> X_s mu+ mu-

We have searched for the flavor-changing neutral current decay b -> s mu+ mu- in p pbar collisions at sqrt(s) = 1.8 TeV with the DO detector at Fermilab. We determine the 90% confidence level limit for the branching fraction to be B(b -> X_s mu+ mu-) < 3.2 x 10^{-4}. We argue that this limit is more stringent than the best published limit on this decay rate.

hep-ex↗

arXiv1997

Color Coherent Radiation in Multijet Events from ppbar Collisions at sqrt(s) = 1.8 TeV

We report on a study of color coherence effects in ppbar collisions at a center of mass energy sqrt(s)=1.8 TeV. The data were collected with the D0 detector during the 1992-1993 run of the Fermilab Tevatron Collider. We observe the presence of initial-to-final state color interference with the spatial correlations between soft and hard jets in multijet events in the central and in forward pseudorapidity regions. The results are compared to Monte Carlo simulations with different color coherence implementations and to the predictions of O(alpha_s^3) QCD calculations.

hep-ex↗

arXiv1997

Search for Scalar Leptoquark Pairs Decaying to Electrons and Jets in pbarp Collisions

We have searched for the pair production of first generation scalar leptoquarks in the eejj channel using the full data set (123 pb-1) collected with the D0 detector at the Fermilab Tevatron during 1992--1996. We observe no candidates with an expected background of approximately 0.4 events. Comparing the experimental 95% confidence level upper limit to theoretical calculations of the cross section with the assumption of a 100% branching fraction to eq, we set a lower limit on the mass of a first generation scalar leptoquark of 225 GeV/c^2. The results of this analysis rule out the interpretation of the excess of high Q^2 events at HERA as leptoquarks which decay exclusively to eq.

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