New Results in Kaon Physics from NA48 and KTEV

In the recent year many new results from kaon decays have been reported from both the NA48 experiment at CERN and the KTeV experiment at Fermilab. Both experiments have new and improved measurements of the parameter Re(epsilon'/epsilon) of direct CP violation in the neutral kaon system. Also several new results on rare and very rare K_L decays were reported. In addition, the NA48 collaboration has performed special high-intensity K_S run periods, with the first results now being available.Comment: Invited talk at the XXIII Physics in Collisions Conference (PIC03), Zeuthen, Germany, June 2003, 14 pages, LaTeX, 12 eps figures. PSN FRAT0

New Results on Kaon Decays from NA48

New measurements of K_L and K_S decays from the NA48 experiment are presented. From data taken in the year 2001, the value of the K_e3 charge asymmetry has been determined to delta_L(e) = (3.317 +- 0.070(stat) +- 0.072 (syst)) x 10^-3. From a special high-intensity K_S run period performed in 2000, NA48 has found a limit of 1.4 x 10^-6 on the K_S -> 3 pi0 branching ratio and measured the parameter eta_000. The same data sample also leads to the first observation of the rare decay K_S -> pi0 gamma gamma. All results are still preliminary.Comment: 6 pages, 9 figures, to appear in the proceedings of the 38th Rencontres de Moriond, Electro-Weak Interactions and Unified Theories, Les Arcs, France, March 200

Wigner-Cusp in Kaon Decays and Determination of pi pi Scattering Lengths

In the last few years it has become possible to study low energy pi pi scattering in kaon decays to three pions, thanks to the high statistics measurement of K+- -> pi+- pi0 pi0 decays performed by the NA48/2 experiment at the CERN SPS. At the pi+ pi- threshold, the pi0 pi0 mass spectrum exhibits a Wigner-cusp, from which the S-wave pi pi scattering lengths are extracted with high precision. This measurement is complementary to the extraction of the scattering lengths from K_e4 decays, which is also performed by the NA48/2 experiment.Comment: 10 pages, proceedings of plenary talk at MENU 2007, FZ Juelich, Sep 2007 (final version after referee's comments

Tests of chiral perturbation theory in rare kaon decays

The neutral kaon decays $K_{S} \to \gamma\gamma$ and $K_{L} \to \pi^{0}\gamma\gamma$ are very sensitive to higher order loop effects of chiral perturbation theory (ChPT). New measurements of the NA48 experiment show that ChPT contributions of $\mathcal{O}(p^{6})$ cannot be neglected in these modes. In addition a new measurement of the related decay $K_{L} \to \gamma\gamma$ and an upper limit of the rate of $K_{S} \to \pi^{0}\gamma\gamma$ are presented

New Results on Xi0 Hyperon Decays

In the recent years many new measurements of the decay of the neutral Xi0 hyperon have been reported both by the NA48/1 and the KTeV collaboration. The results are based on data samples of more than 2 billion Xi0 decays. In this report new measurements of the Xi0 lifetime, decay asymmetries, and semileptonic decay rates are presented. The latter allow the extraction of the CKM matrix element |V_us|, complementary to kaon decays.Comment: 7 pages, contribution to the Proceedings of HQL06, October 2006, Munic

NaNu: Proposal for a Neutrino Experiment at the SPS Collider located at the North Area of CERN

Several experiments have been proposed in the recent years to study the nature of tau neutrinos, in particular aiming for a first observation of tau anti-neutrinos, more stringent upper limit on its anomalous magnetic moment as well as new constrains on the strange-quark content of the nucleon. We propose here a new low-cost neutrino experiment at the CERN North area, named NaNu (North Area NeUtrino), compatible with the realization of the future SHADOWS and HIKE experiments at the same experimental area.Comment: 7 pages, 6 figure

Enteroaggregative Escherichia coli as a Potential Cause of Diarrheal Disease in Adults Infected with Human Immunodeficiency Virus

Stools of 68 human immunodeficiency virus (HIV)-infected adults with diarrhea and 60 without diarrhea were examined for enteroaggregative Escherichia coli (EAggEc) by HeLa cell adherence assay. EAggEc were present in stools of 30 patients with and 18 without diarrhea (P = .05). CD4 cell counts of patients with EAggEc and diarrhea were significantly lower than those of patients with EAggEc without diarrhea (P = .02). There was no difference in the mean duration of diarrheal symptoms or in the number of stools per day between patients with EAggEc and those without. None of the EAggEc strains were positive by polymerase chain reaction for adherence fimbria, but 11 strains were positive for EAggEc heat-stable toxin EAST/1. Of the EAggEc strains, 51% were resistant to trimethoprim-sulfamethoxazole and 65% were resistant to ampicillin. EAggEc may be a pathogen in HIV-infected patients with diarrhea; HIV-infected patients with EAggEc appear to be more symptomatic when HIV disease is more advance