Study of the K±±0e+e decay by the NA48/2 experiment at CERN B Bloch-Devaux Search for Dark Photon at NA48/2, and measurement of 0 form factor Mauro Raggi Searches for Lepton Number Violation and resonances in K± decays at NA48/2 M. Piccini Chiral Perturbation Theory tests at NA48/2 and NA62 experiments at CERN Massimo Lenti Kaons at CERN: status and prospects Giuseppina Anzivino Scale out databases for CERN use cases Zbigniew Baranowski, Maciej Grzybek, Luca Canali et al. Accelerating physics teaching at CERN

S. Pislak, R. Appel, G.S. Atoyan, B. Bassalleck, D.R. Bergman, N. Cheung, S. Dhawan, H. Do, J. Egger, S. Eilerts, W. Herold, V.V. Issakov, H. Kaspar, D.E. Kraus, D. M. Lazarus, P. Lichard, J. Lowe, J. Lozano, H. Ma, W. Majid, A.A. Poblaguev, P. Rehak, A. Sher, J.A. Thompson, P. Truöl, and M.E. Zeller 1 Brookhaven National Laboratory, Upton, NY 11973, USA 2 Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, USA 3 Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA 4 Institute for Nuclear Research of Russian Academy of Sciences, Moscow 117 312, Russia 5 Paul Scherrer Institut, CH-5232 Villigen, Switzerland 6 Physics Department, Yale University, New Haven, CT 06511, USA 7 Physik-Institut, Universität Zürich, CH-8057 Zürich, Switzerland (February 7, 2008)

Experiment 865 at the Brookhaven AGS has observed the decay K+→e+νeμ+μ−. The branching ratio extracted is (1.72±0.37(stat)±0.17(syst)±0.19(model))×10−8 where the third term in the error results from the use of a model to extrapolate into a kinematic region dominated by background.Received 12 May 2005DOI:https://doi.org/10.1103/PhysRevD.73.037101©2006 American Physical Society

Experiment 865 at the Brookhaven AGS has observed the decay K+-> e(+)nu(e)mu(+)mu(-). The branching ratio extracted is (1.72 +/- 0.37(stat)+/- 0.17(syst)+/- 0.19(model))x10(-8) where the third term in the error results from the use of a model to extrapolate into a kinematic region dominated by background.

The reaction anti-proton + proton -> anti-\Lambda + \Lambda -> anti-proton + \pi^+ + proton + \pi^- has been measured with high statistics at anti-proton beam momentum of 1.637 GeV/c. The use of a transversely-polarized frozen-spin target combined with the self-analyzing property of \Lambda/anti-\Lambda decay allows access to unprecedented information on the spin structure of the interaction. The most general spin-scattering matrix can be written in terms of eleven real parameters for each bin of scattering angle, each of these parameters is determined with reasonable precision. From these results all conceivable spin-correlations are determined with inherent self-consistency. Good agreement is found with the few previously existing measurements of spin observables in anti-proton + proton -> anti-\Lambda + \Lambda near this energy. Existing theoretical models do not give good predictions for those spin-observables that had not been previously measured.

Based on results of a search for the lepton-family-number-violating decay K+->pi(+)mu(+)e(-) with data collected by experiment E865 at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, we place an upper limit on the branching ratio at 2.1 x 10(-11) (90% C.L.). Combining the results with earlier E865 data and those of a previous experiment, E777, an upper limit on the branching ratio of 1.3 x 10(-11) (90% C.L.) is obtained.

The reaction p-barp {yields}{lambda}-bar {lambda} was examined by LEAR experiment PS185/3 at 1.525 and 1.640 GeV/c. The proton target was transversely polarized in order to measure the depolarization and spin transfer. Theoretical calculations of D {sub nn}, the component of the depolarization normal to the production plane, differ greatly according to whether quark-gluon or meson-exchange models are employed. The measured D {sub nn} and spin transfer K {sub nn} appear to be inconsistent with the specific models cited.

The reaction pp→ΛΛ was examined by LEAR experiment PS185/3 at 1.525 and 1.640 GeV/c. The proton target was transversely polarized in order to measure the depolarization and spin transfer. Theoretical calculations of Dnn, the component of the depolarization normal to the production plane, differ greatly according to whether quark-gluon or meson-exchange models are employed. The measured Dnn and spin transfer Knn appear to be inconsistent with the specific models cited.

We report experimental details and results of a new measurement of the decay K+-->pi(+)pi(-)e(+)nu(e)(K-e4). A sample of more than 400,000 K-e4 events with low background has been collected by Experiment 865 at the Brookhaven Alternate Gradient Synchrotron. From these data, the branching ratio (4.11+/-0.01+/-0.11)x10(-5) and the pipi invariant mass dependence of the form factors F, G, and H of the weak hadronic current as well as the phase shift difference delta(0)(0)-delta(1)(1) for pipi scattering were extracted. Using constraints based on analyticity and chiral symmetry, a new value with considerably improved accuracy for the s-wave pipi scattering length a(0)(0) has been obtained also: a(0)(0)=0.216+/-0.013 (stat)+/-0.002 (syst)+/-0.002 (theor).

E865 at the Brookhaven National Laboratory AGS collected about 70 000 K(+)(e3) events to measure the K(+)(e3) branching ratio relative to the observed K+-->pi(+)pi(0), K+-->pi(0)micro(+)nu, and K+-->pi(+)pi(0)pi(0) decays. The pi(0) in all the decays was detected using the e(+)e(-) pair from pi(0)-->e(+)e(-)gamma decay and no photons were required. Using the 2002 Particle Data Group branching ratios for the normalization decays, we obtain BR(K(+)(e3(gamma)))=(5.13+/-0.02(stat)+/-0.09(syst)+/-0.04(norm))%, where K(+)(e3(gamma)) includes the effect of virtual and real photons. This result is approximately 2.3sigma higher than the current Particle Data Group value. Implications for the V(us) element of the CKM matrix, and the matrix's unitarity are discussed.

Spin transfer observables for the strangeness-production reaction Antiproton-Proton -> Antilambda-Lambda have been measured by the PS185 collaboration using a transversely-polarized frozen-spin target with an antiproton beam momentum of 1.637 GeV/c at the Low Energy Antiproton Ring at CERN. This measurement investigates observables for which current models of the reaction near threshold make significantly differing predictions. Those models are in good agreement with existing measurements performed with unpolarized particles in the initial state. Theoretical attention has focused on the fact that these models produce conflicting predictions for the spin-transfer observables D_{nn} and K_{nn}, which are measurable only with polarized target or beam. Results presented here for D_{nn} and K_{nn} are found to be in disagreement with predictions from existing models. These results also underscore the importance of singlet-state production at backward angles, while current models predict complete or near-complete triplet-state dominance.