WG3 Session 2 
March 17, 10:30am12:35pm (Ballroom A)  V_{td} and V_{ts} chair:L.Lellouch 


Mixing and lifetimes  
10:3010:40 (Exp)  Determination of the Dmeson decay constants  Anders Ryd  
10:5011:15 (Th)  Matrix elements for B_{s}, B_{d} mixing, and for leptonic decays of B and D_{d,s}  Andreas Kronfeld  
11:2511:35 (Exp)  B_{d} mixing and lifetimes  Nick Hastings  
11:4512:00 (Th)  Lifetimes and width differences of bhadrons  Cecilia Tarantino  
12:1012:25 (Th)  Matrix elements for Kaon mixing  Chris Dawson 
Mixing and lifetimes:
 ΔM_{s} and ΔM_{d}:
 What are the most important remaining systematics in the calculation of ΔB=2 matrix elements?
 What are the prospects for eliminating them?
 Is ΔM_{d}/ΔM_{s} cleaner theoretically than ΔM_{d}?
 What is the real impact of F_{Ds} and F_{D+} measurements on the determination of F_{Bs} and F_{Bd}?
 Is more experimental accuracy in F_{Ds} and F_{D+} necessary?
 What is the CLEO/BES expected precision for F_{Ds} and F_{D+}? At what precision does it become systematics limited?
 Lifetime ratios and differences:
 Can theory explain all observed lifetime ratios and differences?
 Could new physics be reliably discovered in ΔΓ_{s} ?
 What are the prospects for including perturbative and nonperturbative contributions of penguin operators and the nonvalence currentcurrent contributions?
 Can anything be learned from a more precise measurement of the Λ_{b}/B_{d} lifetime ratio until then?
 Any plans for unquenched calculations?
 What is the value, to other experimental measurements or to CKM constraints, of improved precision in lifetimes, lifetime differences, lifetime ratios, and ΔM_{d}? What is the ultimate precision expected in these quantities from B factories?
 Kaon mixing:
 What is the future of CKM constraints from K^{0} mixing/CP violation? Will the theoretical precision improve?
 Calculations with certain lattice regularizations suggest that B_{K} may be smaller than the canonical quenched result of JLQCD. How seriously should this effect be taken?
 Do we have strong evidence that B_{K} is smaller when the quenched approximation is removed?
 For both lattice subjects in this session:
 Are we able to reliably match onto chiral perturbation theory to perform the required chiral extrapolation?
 Are there estimates of the systematics associated with the procedure used for including sea quark effects with staggered fermions?