2876125
Improved estimatesofrare K decay matrix-elementsfrom K '3 decays
The estimation of rare K decay matrix elements from K{sub l3} experimental data is extended beyond LO in chiral perturbation theory. Isospin-breaking effects at next-to-leading order (and partially next-to-next-to-leading order) in the chiral perturbation theory expansion, as well as QED radiative corrections, are now accounted for. The analysis relies mainly on the cleanness of two specific ratios of form factors, for which the theoretical control is excellent. As a result, the uncertainties on the K{sup +}{yields}{pi}{sup +}{nu}{nu} and K{sub L}{yields}{pi}{sup 0}{nu}{nu} matrix elements are reduced by a factor of about 7 and 4, respectively, and similarly for the direct CP-violating contributions to K{sub L}{yields}{pi}{sup 0}e{sup +}e{sup -} and K{sub L}{yields}{pi}{sup 0}{mu}{sup +}{mu}{sup -}. They could be reduced even further with better experimental data for the K{sub l3} slopes and the K{sub l3}{sup +} branching ratios. As a result, the nonparametric errors for B(K{yields}{pi}{nu}{nu}) and for the direct CP-violating contributions to B(K{sub L}{yields}{pi}{sup 0}l{sup +}l{sup -}) are now completely dominated by those on the short-distance physics.
118649028
Tree-level contributions to the rare decays B+ ---> pi+ nu anti-nu, B+ ---> K+ nu anti-nu, and B+ ---> K*+ nu anti-nu in the Standard Model
The tree-level contributions to the rare decays B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu are analyzed and compared to those occurring in K+ --> pi+ nu anti-nu, D+ --> pi+ nu anti-nu, and Ds+ --> pi+ nu anti-nu. It is shown that these purely long-distance contributions, arising from the exchange of a charged lepton, can be significant in B+ decays for an intermediate tau, potentially blurring the distinction between the modes used to extract B --> tau nu and those used to probe the genuine short-distance b --> (s,d) nu anti-nu FCNC transitions. Numerically, the tree-level contributions are found to account for 97%, 12% and 14% of the total B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu rates, respectively.
119335059
Radiative kaon decays and the penguin contribution to the Delta I = 1/2 rule
A consistent census of penguins in the Delta I = 1/2 rule is taken from the eta0 pole contribution to the radiative KL to gamma gamma, KS to pi0 gamma gamma and K+ to pi+ gamma gamma decay modes. We briefly comment on its impact for KL to pi0 pi0 gamma gamma, KL to pi+ pi- gamma and check its compatibility with the KL - KS mass difference and the CP violating epsilon-prime / epsilon parameter. Comment: 37 pages, 16 figures
14402674
Supersymmetric models with minimal flavor violation and their running
We revisit the formulation of the principle of minimal flavor violation (MFV) in the minimal supersymmetric extension of the standard model, both at moderate and large tan β, and with or without new CP-violating phases. We introduce a counting rule which keeps track of the highly hierarchical structure of the Yukawa matrices. In this manner, we are able to control systematically which terms can be discarded in the soft SUSY breaking part of the Lagrangian. We argue that for the implementation of this counting rule, it is convenient to introduce a new basis of matrices in which both the squark (and slepton) mass terms as well as the trilinear couplings can be expanded. We derive the RGE for the MFV parameters and show that the beta functions also respect the counting rule. For moderate tan β, we provide explicit analytic solutions of these RGE and illustrate their behavior by analyzing the neighborhood (also switching on new phases) of the SPS-1a benchmark point. We then show that even in the case of large tan β, the RGE remain valid and that the analytic solutions obtained for moderate tan β still allow us to understand the most important features of the running of the parameters, as illustrated with the help of the SPS-4 benchmark point.
17438804
What could be learnt from positronium for quarkonium
In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing standard positronium decay processes. Then, it is shown how applying the method to quarkonia sheds new light on some longstanding puzzles. Comment: 12 pages, 10 figures. Talk given at the ETH Workshop on Positronium Physics, May 30-31, 2003, Zurich, Switzerland
809980
Long-distance effects in rare K decays
Rare K decays provide for very clean tests of the Standard Model, and are especially suited to search for New Physics signal. In this talk, recent progresses in the estimation of long-distance effects induced by light quarks in KL to pi0 mu+ mu- and K+ to pi+ nu nu are reported.
120652887
STATUS OF THE MINOS EXPERIMENT
The MINOS experiment is designed to search for neutrino oscillations. A neutrino beam from Fermilab is observed by the Near and Far detectors, separated by 735km. A comparison of the observed neutrino events at the two locations allows a measurement of the oscillation parameters to be made. Commissioning of the Near detector is underway and the Far detector is collecting cosmic ray and atmospheric neutrino data. Analysis of the atmospheric neutrino events has begun and neutrino, antineutrino event separation has been achieved. Data collection with the NuMI beam will begin in December 2004.
125682886
Calibration of the MINOS detectors and extraction of neutrino oscillation parameters