Search For Second Generation Leptoquarks Research Articles

Executive function measures in healthy relatives of bipolar and schizophrenia probands

We report on a search for second generation leptoquarks (LQ2) which decay into a muon plus quark in pp¯ collisions at a center-of-mass energy of s=1.96TeV in the D0 detector using an integrated luminosity of about 300 pb−1. No evidence for a leptoquark signal is observed and an upper bound on the product of the cross section for single leptoquark production times branching fraction β into a quark and a muon was determined for second generation scalar leptoquarks as a function of the leptoquark mass. This result has been combined with a previously published D0 search for leptoquark pair production to obtain leptoquark mass limits as a function of the leptoquark–muon–quark coupling, λ. Assuming λ=1, lower limits on the mass of a second generation scalar leptoquark coupling to a u quark and a muon are mLQ2>274GeV and mLQ2>226GeV for β=1 and β=1/2, respectively.

Search for Second Generation Leptoquark Pairs Decaying toμν+jetsinpp¯Collisions at√s=1.8TeV

We report on a search for second generation leptoquarks (LQ) produced in p (p) over bar collisions at root s = 1.8 TeV using the DO detector at Fermilab. Second generation leptoquarks are assumed to be produced in pairs and to decay to either mu. or nu and either a strange or a charm quark (q). Limits an placed on sigma(p (p) over bar --> LQ --> mu nu + jets) as a function of the mass of the leptoquark. For equal branching ratios to mu q and nu q, 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.

Search for Second Generation Leptoquarks in the Dimuon Plus Dijet Channel ofpp¯Collisions at√s=1.8TeV

We report on a search for second generation leptoquarks (Phi_2) using a data sample corresponding to an integrated luminosity of 110 pb^{-1} collected at the Collider Detector at Fermilab. We present upper limits on the production cross section as a function of Phi_2 mass, assuming that the leptoquarks are produced in pairs and decay into a muon and a quark with branching ratio beta. Using a Next-to-Leading order QCD calculation, we extract a lower mass limit of M_{\Phi_2} > 202 (160) GeV$/c^{2} at 95% confidence level for scalar leptoquarks with beta=1(0.5).