S. Okada

Structure near the K - + p + p threshold in the in-flight 3 He(K - , Λp)n reaction

To search for an S = -1 di-baryonic state which decays toΛp, the 3He(K-,Λp)nmissing reaction was studied at 1.0 GeV/c. Unobserved neutrons were kinematically identified from the missing mass MX of the 3He (K-,Λp) X reaction in order to have a large acceptance for the Λpn final state. The observed Λpn events, distributed widely over the kinematically allowed region of the Dalitz plot, establish that the major component comes from a three-nucleon absorption process. A concentration of events at a specific neutron kinetic energy was observed in a region of low momentum transfer to the Λp. To account for the observed peak structure, the simplest S-wave polewas assumed to exist in the reaction channel, having a Breit-Wigner formin energy and with a Gaussian form factor. A minimum X2 method was applied to deduce its mass, MX = 2355+6 -8 (stat.) ±12 (syst.)MeV/c2, and decay width, γX = 110+19 -17 (stat.) ±27 (syst.)MeV/c2, respectively. The form factor parameter QX ∼ 400MeV/c implies that the range of the interaction is about 0.5 fm.

Strangeness in the Universe? Advances and perspectives in the low-energy kaon-nucleon/nuclei interaction studies at the DA

C. Curceanu, M. Bazzi, G. Beer, C. Berucci, D. Bosnar, A.M. Bragadireanu, M. Cargnelli, A. d’Uffizi, L. Fabietti, C. Fiorini, F. Ghio, C. Guaraldo, R.S. Hayano, M.Iliescu, T. Ishiwatari, M. Iwasaki, P. Levi Sandri, J. Marton, S. Okada, D. Pietreanu, K. Piscicchia, M. Poli Lener, T. Ponta, R. Quaglia, A. Romero Vidal, E. Sbardella, F Schembari, A. Scordo, H. Shi, D.L. Sirghi, F. Sirghi, H. Tatsuno, I. Tucakovic, O. Vazquez Doce, E. Widmann, J. Zmeskal INFN, Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044, Frascati (Roma), Italy Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada Stefan-Meyer-Institut fur subatomare Physik, Vienna, Austria University of Zagreb, Zagreb, Croatia Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Romania Excellence Cluster Universe, Technische Universitat Munchen, Garching, Germany Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy INFN Sezione di Milano, Milano, Italy INFN Sezione di Roma I and Istituto Superiore di Sanita, Roma, Italy The University of Tokyo, Tokyo, Japan RIKEN, The Institute of Physics and Chemestry Research, Saitama, Japan University of Santiago de Compostela, Santiago de Compostela, Spain

{\Phi}

This work presents the SIDDHARTA experimental results on the kaonic hydrogen and helium atoms, reviewing some fundamental aspects of the physics case. After an introduction about the fundamental role played by these bound systems and their X-ray transitions measurements in testing the reliability of the Chiral Perturbation Theory as a realisation of Quantum Chromodynamics at low energies, a short review of the light kaonic atoms physics is given. The review, highlighting the experimental challenges, aims to better understand the SIDDHARTA performances to obtain the most precise spectroscopic X-ray measurements of these light kaonic atoms. A description of the SIDDHARTA apparatus is followed by the presentation of the results on kaonic hydrogen and helium, nowadays the most precise available in literature.

NE collider

Kaonic Hydrogen and Helium X-ray measurements play nowadays a fundamental role in testing the reliability of the Chiral Perturbation Theory as a realisation of the Quantum Chromodynamics at low energies. Dictated by both electromagnetic and strong interaction, X-ray transitions at lower energy levels of these complex bound systems offer indeed the unique opportunity to perform a threshold measurements of zero-energy meson-nucleon scattering. Nowadays the SIDDHARTA experiment at DAFNE collider is the only apparatus which can provide such kind of measurements with the high precision needed to disentangle different theoretical calculation scenarios. In this work we present the SIDDHARTA experiment performances and results, with a focus on the main topics of light kaonic atom physics.

Kaonic atoms measurements at the DAΦNE collider: the SIDDHARTA experiment

We will measure the X‐rays from kaonic 3He 3d →  2p transition with a precision below 2 eV. It can provide crucial information on the kaon‐nucleus strong interaction. The experiment (J‐PARC E17) will be performed as Day‐1, which is one of the first experiments in the J‐PARC hadron facility in the year 2011. An overview and the present status of the J‐PARC E17 experiment are described.