Measurement of partial widths and search for direct CP violation in D0 meson decays to K-K+ and pi-pi+

We present a measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D0 mesons produced in pp collisions at sqrt[s]=1.96 TeV. We use a sample of 2x10(5) D(*+)-->D0pi(+) (and charge conjugate) decays with the D0 decaying to K-pi(+), K-K+, and pi(-)pi(+), corresponding to 123 pb(-1) of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure Gamma(D0-->K-K+)/Gamma(D0-->K-pi(+))=0.0992+/-0.0011+/-0.0012, Gamma(D0-->pi(-)pi(+))/Gamma(D0-->K-pi(+))=0.035 94+/-0.000 54+/-0.000 40, A(CP)(K-K+)=(2.0+/-1.2+/-0.6)%, and A(CP)(pi(-)pi(+))=(1.0+/-1.3+/-0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic.     

Benzopyrones—V Mass spectra of some ethyl 4-oxochromen-2-carboxylates and related compounds

The mass spectra of 23 chromone derivatives are recorded and interpreted. Most of these are ethyl 4-oxochromen-2-carboxylate derivatives, which with two exceptions, show the molecular ion as the base peak. In the spectrum of the unsubstituted ester (XVIII), the other most important fragments are [M—C2H4], [M—OEt], [M—C2H4—CO], [M—CO2Et + 1] and the benzocyclopropenyl ion. 6-Hydroxy-2-methylchromone and several of its derivatives undergo a retro-Diels-Alder reaction (R.D.A.) and also lose the carbonyl group. Ethyl 6-amino-4-oxochroman-2-carboxylate (XXIII) shows an R.D.A. reaction as well as losing the CO2Et group. The mass spectrum of 4-oxochromen-2-carboxylic acid has been studied.     

Helium scattering from metal surfaces: potential determination and crystallography

We describe a method for determining the interaction potential between a helium atom and a metal surface from diffraction data. Results are presented for He/Ni(110) and He/Cu(110). For He/Cu(110) the potential 3s in good agreement with a first principles calculation but this is not true for He/Ni(110). We also show that a surface relaxation of 10% produces measurable changes in intensities.     

Interactions of fast and slow waves in hyperbolic systems with two time scales

We consider certain symmetric hyperbolic systems of nonlinear partial differential equations whose solutions vary on two time scales. The large part of the spatial operator is assumed to have constant coefficients, but a nonlinear term multiplying the time derivatives is allowed. We show that if the initial data are not prepared correctly for the suppression of the fast scale motion, but contain errors of amplitude O(?), then the perturbation in the solution will also be of amplitude O(?). Further, if the large part of the spatial operator is nonsingular, we show that the error introduced in the slow scale motion will be of amplitude O(?²), even though fast scale waves of amplitude O(?) will be present in the solution.     

Solar neutrinos and a proposed level in Be

Arguments are given against the existence of a narrow 0⁺ level in ⁶Be just above the ³He+³He threshold, which has been postulated recently in order to explain the low observed flux of solar neutrinos.