Experimental Results of Neutron Fluence Outside an Iron Shield in the Forward Direction

This work represents the first systematic study at a high energy accelerator of the depth dependence of neutron fluence in longitudinal shielding

Large mass dileptons from the passage of jets through quark gluon plasma

We calculate the emission of large mass dileptons originating from the annihilation of quark jets passing through quark gluon plasma. Considering central collisions of heavy nuclei at SPS, RHIC and LHC energies, we find that the yield due to the jet-plasma interaction gets progressively larger as the collision energy increases. We find it to be negligible at SPS energies, of the order of the Drell-Yan contribution and much larger than the normal thermal yield at RHIC energies and up to a factor of ten larger than the Drell-Yan contribution at LHC energies. An observation of this new dilepton source would confirm the occurrence of jet-plasma interactions and of conditions suitable for jet-quenching to take place.Comment: 9 pages, 11 figures; references added, improved calculation, conclusions unchange

Limits on WWgamma and WWZ Couplings from W Boson Pair Production

The results of a search for W boson pair production in pbar-p collisions at sqrt{s}=1.8 TeV with subsequent decay to emu, ee, and mumu channels are presented. Five candidate events are observed with an expected background of 3.1+-0.4 events for an integrated luminosity of approximately 97 pb^{-1}. Limits on the anomalous couplings are obtained from a maximum likelihood fit of the E_T spectra of the leptons in the candidate events. Assuming identical WWgamma and WWZ couplings, the 95 % C.L. limits are -0.62<Delta_kappa<0.77 (lambda = 0) and -0.53<lambda<0.56 (Delta_kappa = 0) for a form factor scale Lambda = 1.5 TeV.Comment: 10 pages, 1 figure, submitted to Physical Review

Open Problems on Central Simple Algebras

We provide a survey of past research and a list of open problems regarding central simple algebras and the Brauer group over a field, intended both for experts and for beginners.Comment: v2 has some small revisions to the text. Some items are re-numbered, compared to v

Search for bottom squarks in pbarp collisions at sqrt(s)=1.8 TeV

We report on a search for bottom squarks produced in pbarp collisions at sqrt(s) = 1.8 TeV using the D0 detector at Fermilab. Bottom squarks are assumed to be produced in pairs and to decay to the lightest supersymmetric particle (LSP) and a b quark with branching fraction of 100%. The LSP is assumed to be the lightest neutralino and stable. We set limits on the production cross section as a function of bottom squark mass and LSP mass.Comment: 5 pages, Latex. submitted 3-12-1999 to PRD - Rapid Communicatio

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.Comment: 10 pages, 3 figures, Submitted to PRL, Fixed typo on page bottom of p. 6 (QCD multijet background is 35.4 events

Limits on Anomalous WWgamma and WWZ Couplings

Limits on the anomalous WWgamma and WWZ couplings are presented from a simultaneous fit to the data samples of three gauge boson pair final states in pbar-p collisions at sqrt(s)=1.8 TeV: Wgamma production with the W boson decaying to enu or munu, W boson pair production with both of the W bosons decaying to enu or munu, and WW or WZ production with one W boson decaying to enu and the other W boson or the Z boson decaying to two jets. Assuming identical WWgamma and WWZ couplings, 95 % C.L. limits on the anomalous couplings of -0.30<Delta kappa<0.43 (lambda = 0) and -0.20<lambda<0.20 (Delta kappa = 0) are obtained using a form factor scale Lambda = 2.0 TeV. Limits found under other assumptions on the relationship between the WWgamma and WWZ couplings are also presented.Comment: 13 pages, 3 figures, submitted to Physical Review

Probing BFKL Dynamics in the Dijet Cross Section at Large Rapidity Intervals in ppbar Collisions at sqrt{s}=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (delta_eta) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large delta_eta in ppbar collisions at sqrt{s}=1800 and 630 GeV using the DO detector. The partonic cross section increases strongly with the size of delta_eta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of a_{BFKL}(20GeV)=1.65+/-0.07.Comment: Published in Physical Review Letter