Light pseudoscalar eta and H->eta eta decay in the simplest little Higgs mode

The SU(3) simplest little Higgs model in its original framework without the so-called mu term inevitably involves a massless pseudoscalar boson eta, which is problematic for b-physics and cosmological axion limit. With the mu term introduced by hand, the eta boson acquires mass m_eta ~ mu, which can be lighter than half the Higgs boson mass in a large portion of the parameter space. In addition, the introduced mu term generates sizable coupling of H-eta-eta. The Higgs boson can dominantly decay into a pair of eta's especially when mH below the WW threshold. Another new decay channel of H->Z+eta can be dominant or compatible with H -> WW for mH above the Z+eta threshold. We show that the LEP bound on the Higgs boson mass is loosened to some extent due to this new H->eta eta decay channel as well as the reduced coupling of H-Z-Z. The Higgs boson mass bound falls to about 110 GeV for f=3-4 TeV. Since the eta boson decays mainly into a bb pair, H-> eta eta -> 4b and H-> Z eta -> Z bb open up other interesting search channels in the pursuit of the Higgs boson in the future experiments. We discuss on these issues.Comment: major modification considering the simplest little Higgs model with the mu ter

Managing Early Adoption of Biodiesel by Commercial Fleets

Commercial carriers are being confronted with a variety of decisions regarding long-term petroleum dependency and near-term state and federal policies aimed at increasing the use and content of biodiesel. The purpose of this study is to help members of the Iowa Motor Truck Association identify problems regarding the use of biodiesel blends in trucks. The participating trucking company provided two trucks that ran on similar routes, one truck using regular diesel fuel (B0) and the other one using a 2% biodiesel blend (B2). Complete mileage data and special maintenance concerns were recorded over a period of approximately one year. Iowa State University researchers analyzed and interpreted the field data in terms of fuel economy, variations in maintenance, and seasonal performance. Data acquired from July 2006 through May 2007 were analyzed. Special attention was paid to the concern of fuel filter plugging resulting from using B2. During the period of this study, the B0 truck accumulated approximately 160,000 miles and the B2 truck accumulated about 120,000 miles. Field results indicate that both fuels provided similar miles per gallon numbers, even for different trip lengths. The average miles per gallon were 6.0 for the B0 truck and 6.1 for the B2 truck. Overall, the fuel economies of the two engines using B0 and B2 were very similar. In addition, no fuel filter plugging incidents in the B2 truck were found, even during the winter months. The final data are encouraging in terms of using B2 as an alternative fuel for trucks

Dichloropalladium complexes ligated by 4,5-bis(arylimino)pyrenylidenes: Synthesis, characterization, and catalytic behavior towards Heck-reaction

A series of 4,5-bis(arylimino)pyrenylidenylpalladium(II) chloride complexes (C1–C4) were synthesized and characterized by FT-IR and NMR spectroscopy, elemental analysis as well as by single crystal X-ray diffraction for the representative complexes C1 and C3, which revealed a square planar geometry at the palladium center. All palladium complexes exhibited high activity for the Heck cross-coupling reaction, which were effective when conducted in various solvents. Furthermore, the in-situ mixture of palladium dichloride and the ligand (L1) provided an effective catalytic system for the Heck-reaction