3 research outputs found
Pseudogap in the Optical Spectra of UPd_2Al_3
The in-plane optical conductivity of UPd_2Al_3 was measured at temperatures
K in the spectral range from 1 cm^{-1} to 40 cm^{-1} (0.14
meV to 5 meV). As the temperature decreases below 25 K a well pronounced
pseudogap of 0.2 meV develops in the optical response. In addition we observe a
narrow conductivity peak at zero frequency which at 2 K is less than 1 cm^{-1}
wide but which contains only a fraction of the delocalized carriers. The gap in
the electronic excitations might be an inherent feature of the heavy fermioin
ground state.Comment: 4 pages, 4 figures (submitted to Phys. Rev. Lett.
Production of K-S(,)0 K-*+/- (892) and phi(0) (1020) in minimum bias events and K-S(0) and Lambda(0) in jets in p (p)over-barcollisions at root S 1: 96 TeV
We report measurements of the inclusive transverse momentum (pT) distribution of centrally produced KS0, K±(892), and φ0(1020) mesons up to pT=10 GeV/c in minimum bias events, and KS0 and Λ0 particles up to pT=20 GeV/c in jets with transverse energy between 25 and 160 GeV in pp̄ collisions. The data were taken with the CDF II detector at the Fermilab Tevatron at √s=1.96 TeV. We find that as pT increases, the pT slopes of the three mesons (KS0, K±, and φ) are similar. And using our previous Λ0 results from minimum bias events, we show that the ratio of Λ0 to KS0 as a function of pT in minimum bias events becomes similar to the fairly constant ratio in jets at pT∼5 GeV/c. This suggests that the particles with pTâ‰35 GeV/c in minimum bias events are from "soft" jets, and that the pT slope of particles in jets is insensitive to light quark flavor (u, d, or s) and to the number of valence quarks. We also find that for pT≠24 GeV relatively more Λ0 baryons are produced in minimum bias events than in jets. © 2013 American Physical Society