Study of the semileptonic charm decays D0→π-e+νe, D+→π0e+νe, D0→K-e+νe, and D+→K̄0e+νe
Physical Review D - Particles, Fields, Gravitation and Cosmology 77:11 (2008)
Abstract:
Using a sample of 1.8 million DD̄ mesons collected at the ψ(3770) with the CLEO-c detector, we study the semileptonic decays D0→π-e+νe, D+→π0e+νe, D0→K-e+νe, and D+→K̄0e+νe. For the total branching fractions we find B(D0→π-e+νe)=0.299(11)(9)%, B(D+→π0e+νe)=0.373(22)(13)%, B(D0→K-e+νe)=3.56(3)(9)%, and B(D+→K̄0e+νe)=8.53(13)(23)%, where the first error is statistical and the second systematic. In addition, form factors are studied through fits to the partial branching fractions obtained in five q2 ranges. By combining our results with recent unquenched lattice calculations, we obtain |Vcd|=0.217(9)(4)(23) and |Vcs|=1.015(10)(11)(106), where the final error is theoretical. © 2008 The American Physical Society.Search for resonant tt̄ production in pp̄ collisions at s=1.96TeV
Physical Review Letters 100:23 (2008)
Abstract:
We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680pb-1 collected with the Collider Detector at Fermilab in run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific top-color-assisted technicolor production model, the leptophobic Z′ with width ΓZ′=0.012MZ′, we exclude the mass range MZ′<725GeV/c2 at the 95% confidence level. © 2008 The American Physical Society.A transient radio jet in an erupting dwarf nova.
Science 320:5881 (2008) 1318-1320
Abstract:
Astrophysical jets seem to occur in nearly all types of accreting objects, from supermassive black holes to young stellar objects. On the basis of x-ray binaries, a unified scenario describing the disc/jet coupling has evolved and been extended to many accreting objects. The only major exceptions are thought to be cataclysmic variables: Dwarf novae, weakly accreting white dwarfs, show similar outburst behavior to x-ray binaries, but no jet has yet been detected. Here we present radio observations of a dwarf nova in outburst showing variable flat-spectrum radio emission that is best explained as synchrotron emission originating in a transient jet. Both the inferred jet power and the relation to the outburst cycle are analogous to those seen in x-ray binaries, suggesting that the disc/jet coupling mechanism is ubiquitous.First run II measurement of the W boson mass at the Fermilab Tevatron
Physical Review D - Particles, Fields, Gravitation and Cosmology 77:11 (2008)