WIMPonium and Boost Factors for Indirect Dark Matter Detection
(2008)
First measurement of the fraction of top-quark pair production through gluon-gluon fusion
Physical Review D - Particles, Fields, Gravitation and Cosmology 78:11 (2008)
Abstract:
We present the first measurement of σ(gg→tt̄)/ σ(pp̄→tt̄). We use 0.96fb-1 of s=1.96TeV pp̄ collision data recorded with the CDF II detector at Fermilab. Using charged particles with low transverse momentum in tt̄ events, we find σ(gg→ tt̄)/σ(pp̄→tt̄)=0.07±0.14(stat)±0. 07(syst), corresponding to a 95% confidence level upper limit of 0.33, in agreement with the standard model next-to-leading-order prediction of 0.15±0.05. © 2008 The American Physical Society.Two-photon widths of the χcJ states of charmonium
Physical Review D - Particles, Fields, Gravitation and Cosmology 78:9 (2008)
Abstract:
Using a data sample of 24.5×106 ψ(2S) the reactions ψ(2S)→γχcJ, χcJ→γγ have been studied for the first time to determine the two-photon widths of the χcJ states of charmonium in their decay into two photons. The measured quantities are B(ψ(2S)→γχc0)×B(χc0→γγ)=(2. 17±0.32±0.10)×10-5 and B(ψ(2S)→γχc2) ×B(χc2→γγ)=(2.68±0.28±0.15)×10-5. Using values for B(ψ(2S)→γχc0,c2) and Γ(χc0,c2) from the literature the two-photon widths are derived to be Γγ γ(χc0)=(2.36±0.35±0.22)keV, Γγγ(χ c2)=(0.66±0.07±0.06)keV, and R≡Γγγ(χ c2)/Γγγ(χc0)=0.278±0.050±0.036. The importance of the measurement of R is emphasized. For the forbidden transition, χc1→γγ, an upper limit of Γγγ(χc1) <0.03keV is established. © 2008 The American Physical Society.Measurement of the kT Distribution of Particles in Jets Produced in ppbar Collisions at s**(1/2)=1.96$-TeV
ArXiv 0811.2820 (2008)
Inclusive Search for Squark and Gluino Production in ppbar Collisions at sqrt{s} = 1.96 TeV
ArXiv 0811.2512 (2008)