Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons

We report a measurement of resonance parameters of the orbitally excited (L=1) narrow B^0 mesons in decays to B^{(*)+}\pi^- using 1.7/fb of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B^{*0}_2 state are measured to be m(B^{*0}_2) = 5740.2^{+1.7}_{-1.8}(stat.) ^{+0.9}_{-0.8}(syst.) MeV/c^2 and \Gamma(B^{*0}_2) = 22.7^{+3.8}_{-3.2}(stat.) ^{+3.2}_{-10.2}(syst.) MeV/c^2. The mass difference between the B^{*0}_2 and B^0_1 states is measured to be 14.9^{+2.2}_{-2.5}(stat.) ^{+1.2}_{-1.4}(syst.) MeV/c^2, resulting in a B^0_1 mass of 5725.3^{+1.6}_{-2.2}(stat.) ^{+1.4}_{-1.5}(syst.) MeV/c^2. This is currently the most precise measurement of the masses of these states and the first measurement of the B^{*0}_2 width.Comment: 7 pages, 1 figure, 1 table. Submitted to Phys.Rev.Let

Measurement of the fraction of t-tbar production via gluon-gluon fusion in p-pbar collisions at sqrt(s)=1.96 TeV

We present a measurement of the ratio of t-tbar production cross section via gluon-gluon fusion to the total t-tbar production cross section in p-pbar collisions at sqrt{s}=1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955/pb recorded by the CDF II detector at Fermilab, we select events based on the t-tbar decay to lepton+jets. Using an artificial neural network technique we discriminate between t-tbar events produced via q-qbar annihilation and gluon-gluon fusion, and find Cf=(gg->ttbar)/(pp->ttbar)<0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most precise measurement of this quantity, Cf=0.07+0.15-0.07.Comment: submitted to Phys. Rev.

Validity and worth in the science curriculum: learning school science outside the laboratory

It is widely acknowledged that there are problems with school science in many developed countries of the world. Such problems manifest themselves in a progressive decline in pupil enthusiasm for school science across the secondary age range and the fact that fewer students are choosing to study the physical sciences at higher levels and as careers. Responses to these developments have included proposals to reform the curriculum, pedagogy and the nature of pupil discussion in science lessons. We support such changes but argue from a consideration of the aims of science education that secondary school science is too rooted in the science laboratory; substantially greater use needs to be made of out-of-school sites for the teaching of science. Such usage should result in a school science education that is more valid and more motivating and is better at fulfilling defensible aims of school science education. Our contention is that laboratory-based school science teaching needs to be complemented by out-of-school science learning that draws on the actual world (e.g. through fieldtrips), the presented world (e.g. in science centres, botanic gardens, zoos and science museums) and the virtual worlds that are increasingly available through information and communications technologies (ICT)

The globalization strategies of five Asian tobacco companies: : An analytical framework

With 30% of the world\u27s smokers, two million deaths annually from tobacco use, and rising levels of tobacco consumption, the Asian region is recognised as central to the future of global tobacco control. There is less understanding, however, of how Asian tobacco companies with regional and global aspirations are contributing to the global burden of tobacco-related disease and death. This introductory article sets out the background and rationale for this special issue on \u27The Emergence of Asian Tobacco Companies: Implications for Global Health Governance\u27. The article discusses the core questions to be addressed and presents an analytical framework for assessing the globalisation strategies of Asian tobacco firms. The article also discusses the selection of the five case studies, namely as independent companies in Asia which have demonstrated concerted ambitions to be a major player in the world market

Search for lepton flavor violating decays of a heavy neutral particle in p-pbar collisions at root(s)=1.8 TeV

We report on a search for a high mass, narrow width particle that decays directly to e+mu, e+tau, or mu+tau. We use approximately 110 pb^-1 of data collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence of lepton flavor violating decays is found. Limits are set on the production and decay of sneutrinos with R-parity violating interactions.Comment: Figure 2 fixed. Reference 4 fixed. Minor changes to tex

First-principles Electronic Structure of Superconductor Ca4_4Al2_2O6_6Fe2_2P2_2: Comparison with LaFePO and Ca4_4Al2_2O6_6Fe2_2As2_2

We investigate the electronic structures of iron-based superconductors having perovskite-like blocking layers, %Ca$_4$Al$_2$O$_6$Fe$_2$(As$_{1-x}$P$_x$)$_2$ from first principles. Ca$_4$Al$_2$O$_6$Fe$_2$P$_2$ and Ca$_4$Al$_2$O$_6$Fe$_2$As$_2$ from first principles. Ca$_4$Al$_2$O$_6$Fe$_2$P$_2$ is found to have two hole-like Fermi surfaces around $\Gamma$, and one hole-like Fermi surface around M in the unfolded Brillouin zone. This is in contrast with LaFePO, where no Fermi surface is found around M. The relationship of their band structures and measured transition temperatures of superconductivity is discussed. The number of Fermi surfaces in Ca$_4$Al$_2$O$_6$Fe$_2$P$_2$ is also different from that of Ca$_4$Al$_2$O$_6$Fe$_2$As$_2$, in which only one Fermi surface is formed around $\Gamma$. Analysis using maximally localized Wannier functions clarifies that the differences between their band structures originate mainly from the pnictogen height. We then analyze the alloying effect on the electronic structure of Ca$_4$Al$_2$O$_6$Fe$_2$AsP. It is found that its electronic structure is similar to that of Ca$_4$Al$_2$O$_6$Fe$_2$P$_2$ and Ca$_4$Al$_2$O$_6$Fe$_2$As$_2$ with the average crystal structure, though Ca$_4$Al$_2$O$_6$Fe$_2$AsP contains the pnictogen height disorder. We calculate the generalized susceptibility for Ca$_4$Al$_2$O$_6$Fe$_2$(As$_{1-x}$P$_x$)$_2$ and clarify the factors determining its tendency.Comment: 5 figures, to be published in J. Phys. Soc. Jp