CKM matrix elements from tree-level decays and b-hadron lifetimes

We give an updated summary of the topics covered in Working Group I of the 2nd Workshop on the CKM Unitarity Triangle, with emphasis on the results obtained since the 1st CKM Workshop. The topics covered include the measurement of |V_{ub}|, of |V_{cb}| and of non-perturbative Heavy Quark Expansion parameters, and the determination of b-hadron lifetimes and lifetime differences.Comment: 12 pages, 8 figures. Based on Working Group I's summary talk given by L.L. for the group's convenors (Elisabetta Barberio (SMU), Lawrence Gibbons (Cornell), Toru Iijima (Nagoya), L.L.) at the 2nd Workshop on the CKM Unitarity Triangle, IPPP Durham, 5-9 April, 200

Delta m_d, Delta m_s/Delta m_d and epsilon_K in Quenched QCD

I present quenched, lattice QCD calculations of the hadronic matrix elements relevant for B^0_{d(s)}-\bar B^0_{d(s)} and K^0-\bar K^0 mixing and briefly review the status of lattice predictions.Comment: 7 pages, 1 figure, epsfig, mymoriond (included). Invited talk given at the XXXIVth Rencontres de Moriond: Electroweak Interactions and Unified Theories, Les Arcs, France, 13-20 March 1999. v2: Typos in eqs. 1 and 2 corrected; more appropriate figure 1; other minor cosmetic changes; all results untouched. v3: small changes in wordin

Weak transition matrix elements from finite-volume correlation functions

The two-body decay rate of a weakly decaying particle (such as the kaon) is shown to be proportional to the square of a well-defined transition matrix element in finite volume. Contrary to the physical amplitude, the latter can be extracted from finite-volume correlation functions in euclidean space without analytic continuation. The K -> pi pi transitions and other non-leptonic decays thus become accessible to established numerical techniques in lattice QCD.Comment: Plain TeX source, 19 pages, figures include

Localization transition in weakly-interacting Bose superfluids in one-dimensional quasiperdiodic lattices

We study the localization of collective pair excitations in weakly-interacting Bose superfluids in one-dimensional quasiperiodic lattices. The localization diagram is first determined numerically. For intermediate interaction and quasiperiodic amplitude we find a sharp localization transition, with extended low-energy states and localized high-energy states. We then develop an analytical treatment, which allows us to quantitatively map the localization transition into that of an effective multiharmonic quasiperiodic system.Comment: Final versio