Weak matrix elements on the lattice - circa 1995

Oct, 1995

Citations per year

19951998200120042005051015
Abstract: (arXiv)
Status of weak matrix elements is reviewed. In particular, \epspeps, \bkastg, BKB_K, BBB_B and BBsB_{B_s} are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarized. For \epspeps the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g.\ O6O_6), even bounds on their matrix elements would be very helpful. On \bkastg, a constant behavior of T2T_2 appears disfavored although dependence of T2T_2 could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of VtdV_{td} from BργB\to\rho\gamma. On BKB_K, the preliminary result from JLQCD appears to contradict Sharpe \etal\ JLQCD data seems to fit very well to linear aa dependence and leads to an appreciably lower value of BKB_K. Four studies of BKB_K in the ``full'' (nf=2n_f=2) theory indicate very little quenching effects on BKB_K; the full theory value seems to be just a little less than the quenched result. Based on expectations from HQET, analysis of the BB-parameter (BhB_{h\ell}) for the heavy-light mesons via Bh=B_{h\ell}={}constant+{}+{}constants/mh^\prime/m_{h\ell} is suggested. A summary of an illustrative sample of hadron matrix elements is given and constraints on CKM parameters (e.g.\ Vtd/VtsV_{td}/V_{ts}), on the unitarity triangle and on xs/xdx_s/x_d, emerging from the lattice calculations along with experimental results are briefly discussed. In quite a few cases, for the first time, some indication of quenching errors on weak matrix elements are now becoming available.
  • review
  • fermion: lattice field theory
  • B: radiative decay
  • radiative decay: B
  • K0 anti-K0: mixing
  • K0: nonleptonic decay
  • nonleptonic decay: K0
  • K: B-parameter
  • B: B-parameter
  • CP: violation