A posteriori error estimates for general numerical methods for Hamilton-Jacobi equations. Part I: The steady state case

A new upper bound is provided for the L-norm of the difference between the viscosity solution of a model steady state Hamilton-Jacobi equation, , and any given approximation, . This upper bound is independent of the method used to compute the approximation ; it depends solely on the values that the residual takes on a subset of the domain which can be easily computed in terms of . Numerical experiments investigating the sharpness of the a posteriori error estimate are given.

     

The thermal resistance between electrons and phonons in copper

The thermal impedance between the electron and phonon systems in copper at low temperature is found to be in reasonable agreement with existing theory.     

Observation of parity nonconservation in møller scattering

We report a measurement of the parity-violating asymmetry in fixed target electron-electron (M?ller) scattering: A(PV)=[-175+/-30(stat)+/-20(syst)] x 10(-9). This first direct observation of parity nonconservation in M?ller scattering leads to a measurement of the electron's weak charge at low energy Q(e)(W)=-0.053+/-0.011. This is consistent with the standard model expectation at the current level of precision: sin((2)theta(W)(M(Z))((-)MS)=0.2293+/-0.0024(stat)+/-0.0016(syst)+/-0.0006(theory).     

Search for the lepton-flavor-violating leptonic B(0)-->mu(+/-)tau(-/+) and B(0)-->e(+/-)tau(-/+)

We have searched a sample of 9.6 x 10(6) BB events for the lepton-flavor-violating leptonic B decays, B(0)-->mu(+/-)tau(-/+) and B(0)-->e(+/-)tau(-/+). The tau lepton was detected through the decay modes tau-->lnunu(-) , where l=e, mu. There is no indication of a signal, and we obtain the 90% confidence level upper limits B(B(0)-->mu(+/-)tau(-/+))<3.8 x 10(-5) and B(B(0)-->e(+/-)tau(-/+))<1.3 x 10(-4).     

Flavor altering excitations of composite fermions

Past theoretical studies have considered excitations of a given flavor of composite fermions across composite-fermion quasi-Landau levels. We show that in addition there exists a ladder of flavor changing excitations in which composite fermions are partially dissociated by a removal of some or all of their vortices, and suggest that these are relevant to the intriguing experimental discovery of Hirjibehedin et al. [Phys. Rev. Lett. 91, 186802 (2003)] of coexisting excitation modes of composite fermions of different flavors in the filling factor range 1/3 > nu > or = 1/5.