This paper describes the achievements of the H2020 project INDIGO-DataCloud. The project has provided e-infrastructures with tools, applications and cloud framework enhancements to manage the demanding requirements of scientific communities, either locally or through enhanced interfaces. The middleware developed allows to federate hybrid resources, to easily write, port and run scientific applications to the cloud. In particular, we have extended existing PaaS (Platform as a Service) solutions, allowing public and private e-infrastructures, including those provided by EGI, EUDAT, and Helix Nebula, to integrate their existing services and make them available through AAI services compliant with GEANT interfederation policies, thus guaranteeing transparency and trust in the provisioning of such services. Our middleware facilitates the execution of applications using containers on Cloud and Grid based infrastructures, as well as on HPC clusters. Our developments are freely downloadable as open source components, and are already being integrated into many scientific applications.

We present evidence for the rst observation of electromagnetically bound π ± K ∓pairs (πK-atoms) with the DIRAC experiment at the CERN-PS. The πK-atoms are produced by the 24 GeV/c proton beam in a thin Pt-target and the π ± and K ∓mesons from the atom dissociation are analyzed in a two-arm magnetic spectrometer. The observed enhancement at low relative momentum corresponds to the production of 173 ± 54 πK-atoms. The mean life of πK-atoms is related to the s-wave πKscattering lengths, the measurement of which is the goal of the experiment. From these rst data we derive a lower limit for the mean life of 0.8 fs at 90% condence level.

The results of a search for hydrogen-like atoms consisting of π ∓ K ± mesons are presented. Evidence for π K atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic π K pairs from their breakup in the same target (178 ± 49) as well as in terms of produced π K atoms (653 ± 42). Using these results, the analysis yields a first value for the π K atom lifetime of τ = (2.5 +3.0 −1.8 ) fs and a first measurement of the S-wave isospin-odd π K scattering length |a − 0 | = 1 3 |a 1/2 − a 3/2 | = (0.11 +0.09 −0.04 )M −1 π (a I for isospin I).

A compact sampling calorimeter is developed and used to measure the ratio between positive and negative muons in the cosmic ray flux at momenta below 1 Ge V/ c. The delayed coincidence method is used, based on the reduced mean life time of negative muons due to nuclear capture in matter. It is shown that aluminum is a good choice as capture medium for negative muons and suitable for a simple detector set-up. The muon charge ratio is found to be 1.30 ± 0.05 for a mean momentum of 0.86 Ge V je and over a zenith angle acceptance with 8mean = 26°. Zusammenfassung Ein kompakter Detektor zur Messung des Ladungsverhältnisses von Myonen aus der HöhenstrahlungZur Messung des Ladungsverhält:qisses von positiven zu negativen Myonen aus der Höhen-strahlung für Impulse kleiner 1 Ge V je wird ein kompaktes Sampling-Kalorimeter entwickelt und aufgebaut. Basierend auf der Änderung der mittleren Lebenszeit von negativen Myonen in Materie durch nuklearen Einfang wird eine verbesserte "delayed coincidence" -Methode benutzt. Es wird gezeigt, daß Aluminium als Einfangmedium für negative Myonengeignet ist um eine kompakte Auslegung des Detektors zu ermöglichen. Das Ladungsverhältnis der Myonen bei einem mittleren Impuls von 0.86 Ge V und einem mittleren Zenitwinkel von 26° wird zu 1.30 ± 0.05 bestimmt.

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