International Conference on Exotic Atoms and Related Topics - EXA2014

Marc Diepold for the CREMA collaboration (*) Muonic atoms and ions are hydrogen-like systems that are formed when negative muons are stopped in ordinary matter, replacing all of the atom's electrons by a single muon. The muon's Bohr radius is 200 times smaller than the corresponding electronic Bohr radius in ordinary H-like ions due to the 200 times larger mass of the muon. This results in a increased sensitivity (200^3) to the finite charge and magnetic radius of the nucleus. We have recently determined the proton charge radius by laser spectroscopy of the 2S-2P transition ("Lamb shift") in muonic hydrogen [1,2]. Our value of Rp=0.84087(39) fm is ten times more accurate, but 7 sigma discrepant from the world average, which is based on elastic electron-proton scattering and precision spectroscopy of electronic hydrogen. This so-called "proton radius puzzle" has sparked great interest in both atomic and nuclear physics [3]. Physics beyond the Standard Model has also been proposed to solve the problem. To shed new light on this discrepancy, we have measured the Lamb shift in muonic deuterium and extracted a value of the charge radius of the deuteron. In addition, our most recent experiment [4] has succeeded to measure the Lamb shift in both the mu4He+ and mu3He+ ions, and will be able to provide a ten times more accurate value for the charge radii of the lightest helium isotopes. (*) Charge Radius Experiment using Muonic Atoms [1] R. Pohl et al. (CREMA coll.), Nature 466, 213 (2010). [2] A. Antognini et al. (CREMA coll.), Science 339, 417 (2013). [3] R. Pohl et al., Ann. Rev. Nucl. Part. Sci 63 (2013) (review in advance). [4] A. Antognini et al. (CREMA coll.), Can. J. Phys. 89, 47 (2011).

In this contribution, we will present recent activities at J-PARC by using muonium from the fundamental physics to applied science, especially, on muonium hyperfine structure measurement, muon g-2 and ultra slow muon microscope. 1) Muonium hyperfine structure measurement Muonium is the bound system of a positive muon and an electron. Among the various spectroscopic measurements, ground state hyperfine structure measurement under external magnetic field is rather attractive, since they provide the information of the internal consistency of QED and the most precise value of muon mass, which is important parameter for muon g-2 expereiment. The latest experiment at Los Alamos obtained the remarkable precision value (120ppb for magnetic moment). However, the main uncertainty came from the luck of statics. In this measurement, quasi DC muon beam was adopted. To overcome above statics limit, use of the intense pulsed muon beam obtained J-PARC MUSE H line is ideal. 2) Muon g-2 measurement with muonium ionization One of the indications for New Physics (NP) up to now is in the muon anomalous magnetic moment (g-2); there is 3.3σ discrepancy between the SM prediction and measurement by the E821 experiment at BNL with an accuracy of 0.54 ppm. One of the other windows to NP is the muon electric dipole moment (EDM); having the CPT symmetry, the EDM violates CP, which is necessary for the baryon-antibaryon asymmetry while strongly suppressed in SM. The J-PARC muon g-2/EDM experiment aims to measure the muon g-2 and EDM with an accuracy of 0.1 ppm and a sensitivity of 10-21 e ・cm, respectively, to cast light on NP. To achieve the world best accuracy, high intensity beam at J-PARC MUSE and novel technique of the ultra-cold muon beam, which are obtained thermal muonium ionization by intese laser systems. The ultra-cold beam enables muons to be stored and detected in the magnetic field with no electric focusing, resulting in no need to choose the magic momentum of 3.094 GeV/c used for decades and minimizing dimensions of the stored magnetic field and its systematics. 3) Ultra slow muon microscope with muonium ionization The Ultra Slow Muon Microscope (USMM), under construction at the U-line of the Muon Facility in J-PARC/MLF, will be the first experimental instrumentation in the world possessing two novel muon sources with unique capabilities: an ultra slow muon beam for depth profiling from the surface to the interior of a material, across interfaces, with nanometer resolution near surface, and a muon micro-beam for probing the interior of a material with a resolution of several micrometers at the stopping position. The new spatial imaging method, USMM, is developed for studies of local functional properties and their dynamical aspects near surface and buried interfaces which play key roles in materials and life sciences, such as electron and spin density of states, charge, spin transportation, defects and vacancies in catalytic reaction and so on.

The positronium ground state hyperfine splitting (hfs) has long been of interest as a high-precision test of our understanding of binding in QED. The positronium hfs is particularly sensitive to recoil effects (because the ratio of masses is one) and to virtual electron-positron annihilation, but positronium is insensitive to strong and weak interaction effects. Consequently, the comparison between theory and experiment for the positronium hfs, and more generally the positronium spectrum, tests different aspects of the theory compared to comparisons in other exotic atoms. For the past fifteen years there has been a persistent discrepancy between predicted and measured values of the positronium hfs of about four standard deviations (although a new experimental result is consistent with present theory). Recent experimental work at the University of Tokyo, the University of California Riverside, and related work at ETH Zurich is leading to new high-precision measurements, and the calculation of three-loop corrections has begun. The status of the positronium hfs problem and a discussion of recent progress will be the topic of my talk.

Positronium (or Ps) is a hydrogen-like metastable bound state between an electron and its antiparticle, the positron. This was first produced experimentally by Martin Deutsch in 1951 [1], and since that time Ps has been the subject of numerous experimental studies [2]. However, since antimatter is relatively hard to come by in the lab, and because Ps has a short lifetime against self-annihilation, it is difficult to produce large numbers Ps atoms at the same time, and so experimental work was restricted measurements using one atom at a time. This situation is now starting to change because of developments in positron trapping technology [3] that make it possible to generate intense bursts of positrons and thereby create a “gas” of positronium; this can easily be probed with pulsed lasers making spectroscopic measurements feasible. Moreover, if a high positron beam density is used the resulting Ps atoms may be able to interact with each other, allowing us to observe spin exchanging collisions, Ps-Ps scattering, and the formation of Ps2 molecules. In this talk I will give an overview of some recent experiments performed using a positron trap, including the formation of molecular positronium [4] and a spin polarized Ps gas [5], spectroscopy [6] and scattering [7] of confined Ps, some optical measurements of the Ps hyperfine interval [8] and the production of Rydberg states of Ps [9]. [1] Martin Deutsch “Evidence for the Formation of Positronium in Gases” Phys. Rev. 82, 455 (1951). [2] A. Rich, “Recent experimental advances in positronium research” Rev. Mod. Phys. 53, 127 (1981). [3] C. M. Surko and R. G. Greaves, “Emerging science and technology of antimatter plasmas and trap-based beams” Phys. Plasmas 11, 2333 (2004). [4] D. B. Cassidy and A. P. Mills, Jr., “The production of molecular positronium” Nature (London) 449, 195 (2007). [5] D. B. Cassidy, V. E. Meligne, and A. P. Mills, Jr., “Production of a Fully Spin-Polarized Ensemble of Positronium Atoms” Phys. Rev. Lett. 104, 173401 (2010). [6] D. B. Cassidy, M. W. J. Bromley, L. C. Cota, T. H. Hisakado, H. W. K. Tom, and A. P. Mills, Jr., “Cavity Induced Shift and Narrowing of the Positronium Lyman-α Transition” Phys. Rev. Lett. 106, 023401 (2011). [7] D. B. Cassidy and A. P. Mills, Jr., “Enhanced Ps-Ps Interactions due to Quantum Confinement” Phys. Rev. Lett. 107, 213401 (2011). [8] D. B. Cassidy, T. H. Hisakado, H. W. K. Tom, and A. P. Mills, Jr. “Positronium Hyperfine Interval Measured via Saturated Absorption Spectroscopy” Phys. Rev. Lett. 109, 073401 (2012). [9] D. B. Cassidy, T. H. Hisakado, H. W. K. Tom, and A. P. Mills, Jr. Efficient Production of Rydberg Positronium” Phys. Rev. Lett. 108, 043401 (2012).

We report the status of our ongoing experiment at ETH Zurich (in collaboration with MPQ Garching and Marquette University) aiming to improve by a factor of 5 the current precision of the 1S-2S transition frequency of positronium. This will provide a stringent test of the QED calculations at the alpha⁷m level. We will describe the details of the experimental setup and the first observation of the annihilations of Ps in the 2S state. We will also discuss the prospects of a further improvement of this measurement and of the 1S-2S transition interval of muonium.

We firstly performed the millimeter-wave spectroscopy of the ground-state positronium. The energy difference between ortho-positronium (o-Ps) and para-positronium (p-Ps), the hyperfine structure, is in the millimeter-wave range (203 GHz). Since the magnetic dipole transition from o-Ps to p-Ps is strongly suppressed due to their short lifetime, strong millimeter waves of over 20 kW are required to measure the Breit-Wigner resonance of the transition. This experiment has not yet been performed because previously there were no high-power millimeter-wave devices. We newly developed high-power and frequency-tunable millimeter-wave system composed of a gyrotron and a Fabry-Perot cavity, and directly measured the Breit-Wigner resonance of the transition from o-Ps to p-Ps. This is a breakthrough to use millimeter waves in spectroscopic measurements. Three parameters of this transition, the hyperfine structure, lifetime of p-Ps, and spontaneous transition rate are simultaneously determined through the measured Breit-Wigner resonance. The hyperfine structure of positronium has been indirectly obtained via the Breit-Rabi formula and precise measurement of the Zeeman shifted levels in a static magnetic field of about 1 T. The indirectly measured value differs from QED calculations by 15 ppm (3.9 standard deviations). Some underestimated systematic uncertainties, such as a non-thermalized effect of positronium and non-uniformity of the magnetic field, are suspected. The direct measurement is free from systematic problems due to the static magnetic field. Although current accuracy of the direct measurement is about 700 ppm, it can be improved and used to examine the reported discrepancy in the indirect measurement.

Recent developments and phenomena related to low-energy antikaon interactions with baryonic systems are summarized. Expectations for kaonic deuterium and for the K-deuteron scattering length are outlined in view of planned experiments. Updated information is provided concerning the structure of the Lambda(1405). The quest for kaon condensation and the role of strangeness in dense baryonic matter is discussed with focus on the core of neutron stars.

The X-ray measurements of kaonic atoms play an important role for understanding the low-energy QCD in the strangeness sector. The SIDDHARTA experiment studied the X-ray transitions of 4 light kaonic atoms (H, D, 3He and 4He) using the DAFNE electron-positron collider at LNF (Italy). The most precise values of the shift and width of the kaonic hydrogen 1s state were determined, which are now being used as fundamental information for the low-energy K-p interaction in theoretical studies. The yields of kaonic hydrogen K-series transitions and of the kaonic He3 and He4 L-series were measured, the upper limit of the X-ray yields of kaonic deuterium was determined, important for future K-d experiments. The shifts and widths of the kaonic 3He and 4He 2p states were analyzed, solving the “kaonic helium puzzle” both for the shifts and widths. In this contribution, the experimental approach and the results of SIDDHARTA will be presented, and the plans of the new experiments of kaonic deuterium, will also discussed.

Recently, a study of kaonic nuclei have been actively conducted because they have a rich information, such as the sub-threshold Kbar-N interaction and the behavior of $\mathrm{\Lambda }$(1405) in many body systems. While the existence of kaonic nuclei has been intensively studied both theoretically and experimentally, there is no conclusive result establishing its existence. Here, we have carried out a experiment as a first phase to search for a $K^{-}pp$ bound state, which is considered the simplest kaonic nucleus, by using the $d({\pi }^{+},K^{+})X$ reaction at 1.69 GeV/$c$ (J-PARC E27 experiment). Since the production cross section of the $K^{-}pp$ would not be so large in this reaction, coincidence of high-momentum ($>$ 250MeV/c) proton(s) in large emission angle (${39}^o$-${122}^o$) was required to enhance the signal to background ratio. We have obtained an inclusive $d({\pi }^{+},K^{+})X$ spectrum in a wide missing-mass range from $\mathrm{\Lambda }$, $\mathrm{\Sigma }$ to $\mathrm{\Lambda }$(1405)/$\mathrm{\Sigma }$(1385), in high statics and high energy resolution for the first time. A broad enhancement in the proton coincidence spectra are observed around the missing-mass of 2.27 GeV/$c^2$, which might be attributed to the $K^{-}pp$ production. We will report the results both on inclusive and coincidence analyses.

Experimental annihilation cross sections of antineutrons and antiprotons at very low energies are compared. On a proton target the cross sections vary smoothly up to 600 MeV/c and the differences are described fully by Coulomb focusing. Direct data comparisons for heavier targets are not possible due to lack of overlap between energies and targets. Interpolations with optical potentials that fit all the antiproton-nucleus data from atoms up to 600 MeV/c surprisingly reveal features of Coulomb scattering in the antineutron annihilation cross sections on nuclei. Additional measurements with antiprotons are outlined which will enable direct data-to-data comparisons.

Data on kaon induced reactions on nuclei are scarce and old, dating back to more than 40 years ago. They had been collected in bubble chamber experiments, filled with ${}^4$He, hydrocarbon mixtures or Neon, or in emulsions, composed mainly by mixtures of elements heavier than Oxygen. FINUDA could exploit the decay almost at rest of the $\varphi$(1020) mesons produced at the $e^{+}{e}^{-}$ DA$\mathrm{\Phi }$NE machine to study the interaction of low-energy kaons on several thin targets composed by $p$-shell nuclei, isotopically pure to a level better than 97\%. In parallel to hypernuclear spectroscopy and decay investigations, FINUDA deployed a wide program dedicated to the study of kaon absoption processes, by one or more nucleons, in reactions with the emission of $\mathrm{\Lambda }$ and ${\mathrm{\Sigma }}^{\pm }$ ($Y$) hyperons. The apparatus, a magnetic spectrometer, allowed the recostruction of the hyperons and the identification of the other emitted charged tracks with a large efficiency and good momentum resolution. The study of the kaon absorption reactions in nuclei is particularly complex as the recoiling nuclear system cannot be measured, and often, after the interaction, it is left in an unstable state. Therefore missing mass considerations can be helpful only in a fraction of cases. Dedicated analysis methods, based on models which reproduce by Monte Carlo simulations the elementary absorption reactions and following processes (hyperon conversions and/or final state interactions of nucleons and hyperons, hyperon decays), have been developed to pursue the most complete and precise description as possible of the experimental data. Results on the interactions at rest of negative kaons on ${}^6$Li, ${}^7$Li, ${}^9$Be, ${}^{13}$C and ${}^{16}$O have been obtained. They are of fundamental importance in the understanding of processes involving the dynamics of strange quarks in nuclei and can give valuable inputs in the attempt to model strange nuclear matter behavior at low energies. In this talk a selection of the most recent results achieved by FINUDA in the study of $YN$ pair production will be reported, with a description of the experimental methods for the data selection and the adopted analysis techniques.

The investigation of the kaon-nucleon interaction currently has been intensified in the last years due to new measuremnts of the Λ(1405) and indications on the existence of the 𝑝𝑝𝐾− bound state. Such results are heavily discussed since they can lead to new knowledge about the Antikaon-Nucleon interaction. The reaction pp->pK+Λ In the last years this reaction has been measured at the GSI-Darmstadt with the FOPI and the HADES Spectrometer at beam energies of 3.1 GeV and 3.5 GeV, respectively. New analysis methods have been developed in our group to understand quantitatively all the processes contributing to the pKLambda final state and a statistics of around 1000 and 20000 exclusively measured events has been collected with the FOPI and the HADES spectrometer, respectively. At the FOPI experiment a set of around 1.000 events and in the HADES experiment around 20.000 events of these exclusive reaction 𝑝𝑝 → 𝑝𝐾+Λ could be extracted. These reconstructed exclusive events were analyzed within the Bonn Gatchina Partial Wave Analysis framework, which provides a coherent solution including several resonant and non-resonant production channels. The results have shown, that the inclusion of interferences between different channels is an important effect, which has to be considered in the analysis. Based on the description of the Partial Wave Analysis an upper limit for the cross-section for the production of the 𝑝𝑝𝐾− could be determined. In this talk the analysis method of the Partial Wave Analysis as well as the results for the contribution of different production channels and the upper limit for the 𝑝𝑝𝐾− will be shown. Furthermore a strategy for a future analysis project based on the Partical Wave Analysis for different beam energies will be presented.

The Lambda1405 cannot be described within any theoretical framework as a normal hadron composed of three quarks, but is considered as emerging naturally from the coupling of different meson-baryon states with strange content. Hence one can look at this resonance as a molecule, where the dominant contribution are an Antikaon-proton and pi-Sigma states. Chiral SU(3) provides quantitative predictions for the amplitudes and phases of the poles building the Lambda(1405) but finally many experimental data remain partially unexplained and not described by theory. Experimentally the production of the Lambda(1405) and its decay into a (Sigma-pi)^0 final state can be studied using different entrance channels and the extracted spectral function differs strongly from the latter. In particular in this talk, recent results published by the HADES collaboration from p+p collisions at 3.5 GeV and measured by the KLOE-AMADEUS collaboration in experiment with stopped kaons will be compared and discussed in the context of all the available information about the Lambda(1405). The puzzle remains undisclosed but new data are available.

Hadron physics at moderate energies covers a broad physics spectrum, reaching from investigations of the nucleon structure, the spectroscopy of light-quark states to hadronic interactions. Different accelerator facilities, which provide electron and photon beams, proton and antiproton beams or high-energy lepton collisions, deliver complimentary information. This talk will highlight some exciting recent achievements and discuss them in the context of the planned PANDA experiment.

Among the newly observed structures in the heavy-quarkonium mass region, some have been proposed to be hadronic molecules. We investigate the consequences of heavy-quark flavor symmetry on these heavy meson hadronic molecules. The symmetry allows us to predict new hadronic molecules on one hand, and test the hadronic molecular assumption of the observed structures on the other hand. We explore the consequences of the flavor symmetry assuming the X(3872) and Zb(10610) as an isoscalar DDbar∗ and isovector BBbar∗ hadronic molecule, respectively. A series of hadronic molecules composed of heavy mesons are predicted. In particular, there is an isoscalar 1++ BBar∗ bound state with a mass about 10 580 MeV which may be searched for in the Υ(1S,2S)π+π−π0 mass distribution; the isovector charmonium partners of the Zb(10610) and the Zb(10650) are also predicted, which probably corresponds to the very recently observed Zc(3900) and Zc(4025) resonances by the BESIII Collaboration. On the other hand, owing to heavy antiquark-diquark symmetry, the doubly heavy baryons have approximately the same light-quark structure as the heavy antimesons. As a consequence, the existence of a heavy meson-antimeson molecule implies the possibility of a partner composed of a heavy meson and a doubly heavy baryon. These states are of special interest since they can be considered to be triply heavy pentaquarks.

I will discuss recent developments in hadron spectroscopy, in particular, the hadrons with heavy quarks and their interactions. Hadrons with heavy quarks have new symmetry and dynamics from the QCD point of view. I stress the heavy quark spin symmetry in the spectrum of heavy mesons and baryons, and also the roles of light di-quarks in the heavy baryons.

We perform an analysis of the QCD lattice data on the baryon octet and decuplet masses based on the relativistic chiral Lagrangian. The baryon self energies are computed in a finite volume at next-to-next-to-next-to leading order (N${}^3$LO), where the dependence on the physical meson and baryon masses is kept. The number of free parameters is reduced significantly down to 12 by relying on large-$N_c$ sum rules. Altogether we describe accurately more than 220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC, QCDSF-UKQCD and NPLQCD. Values for all counter terms relevant at N${}^3$LO are predicted. In partic\-ular we extract a pion-nucleon sigma term of 39${}_{-1}^{+2}$ MeV and a strangeness sigma term of the nucleon of ${\sigma }_{sN}={84}_{-4}^{+28}$ MeV. The flavour SU(3) chiral limit of the baryon octet and decuplet masses is determined with $(802\pm 4)$ MeV and $(1103\pm 6)$ MeV. Detailed predictions for the baryon masses as currently evaluated by the ETM lattice QCD group are made

The strong interaction remains one of the most fascinating topic in modern subatomic physics. Quantum ChromoDynamics (QCD) is successfully reproducing the physics phenomena at distances much shorter than the size of the nucleon. Here, perturbation theory can be used yielding results of high precision and predictive power. However, at larger distance scales, however, perturbative methods cannot be applied anymore, although spectacular phenomena, such as the generation of hadron masses and quark confinement, occur. Studies using charmed hadrons and gluon-rich matter have the potential to connect the perturbative and the non-perturbative QCD region. The annihilation of matter with antimatter in the mass regime of charmonium is an ideal environment to discover new states or transitions that could reveal the secrets of the strong interaction. Hadronic and electromagnetic transitions between charmonium states and their decays have been measured with a world-record in precision at experiments exploiting electron-positron colliders such as BESIII in Beijing, China. Moreover, unconventional narrow charmonium-rich states have recently been discovered at various facilities in an energy regime above the open-charm threshold. Thereby, possibly a new era in charmonium spectroscopy is initiated. The PANDA experiment at the research facility FAIR near Darmstadt, Germany, will exploit the annihilation of cooled anti-protons with protons to perform charmonium spectroscopy with a decisive precision. I will present the most promising results that have recently been obtained in the field of charmonium spectroscopy with emphasis on BESIII together with the future perspectives of PANDA.

One of the interesting subjects in hadron spectroscopy is to look for the multiquark configurations. One of candidates is the H-dibaryon (udsuds), and the possibility of the bound H-dibaryon has been recently studied from lattice QCD. We also extend the HAL QCD method to define potential on the lattice between baryons to meson systems including charm quarks to search for the bound tetraquark Tcc (ud ¥bar{c} ¥bar{c}) and Tcs (ud ¥bar{c} ¥bar{c}). In the presentation, after reviewing the HAL QCD method, we report the results on the H-dibaryon, the tetraquark Tcc (ud ¥bar{c} ¥bar{c}) and Tcs (ud ¥bar{c} ¥bar{c}), where we have employed the relativistic heavy quark action to treat the charm quark dynamics with pion masses, m_{¥pi}=410, 570, 700 MeV.

The two B factories, PEP-II with BaBar and KEKB with Belle, have been a real success story. Not only did they measure a large CP violation in B meson decays, constrained angles and sides of the unitary triangle, and studied numerous new phenomena, they also observed a long list of new hadrons, some of which do not seem to fit into the standard meson and baryon schemes. The next generation of B factories, a called Super B factory will search for departures from the Standard model. For this task, a 50 times larger data sample is needed, corresponding to an integrated luminosity of 50/ab. Needless to say that with such a large data sample there are many more topics to explore, including searches for new and exotic hadrons, and investigation of their properties.

The new international accelerator facility FAIR under construction in Darmstadt aims at studying matter at atomic, nuclear, and hadronic levels. I will review different aspects of the current status of the Facility for Antiproton and Ion Research. I will present the focus of the experimental programmes at FAIR, with highlight on open questions addressed by developments in hadron physics, nuclear structure and compressed nuclear matter physics, plasma and atomic physics, as well as related applications.

The CRYRING@ESR project is the early installation of the low-energy storage ring LSR, the Swedish in kind contribution to FAIR, which was proposed as the central decelerator ring for antiprotons at the FLAIR facility. Since the modularized start version of FAIR does not include the erection of the FLAIR building, it was proposed to install the CRYRING storage ring behind the existing experimental storage ring ESR already now. This opens the opportunity to endeavor part of the low energy atomic physics with heavy, highly charged ions as proposed by the SPARC collaboration but also experiments of nuclear physics background in the NUSTAR collaboration much sooner than foreseen in the FAIR general schedule. Furthermore, since the installation of the ring will be handled mostly by FAIR standards, it will be used to test major parts of the FAIR control system for the first time and well ahead of time before it is needed to run SIS100. An option for the future that is being evaluated right now is to feed back antiprotons from the production at FAIR into the existing ESR. This would make antiprotons available in CRYRING and hence enable an early realization of at least part of the low energy antiproton program at FAIR, proposed and advanced by the FLAIR collaboration.

W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, C. Carli, T.Eriksson, S. Maury, W. Oelert, S. Pasinelli and G. Tranquille The CERN Antiproton Decelerator (AD) routinely delivers about 3E7 antiprotons every 100 s and with an energy of 5.3 MeV to experiments. The Extra Low Energy Antiproton ring (ELENA) is a small 30 m circumference synchrotron under construction to further decelerate antiprotons from the AD down to 100 keV, an unusually low energy for synchrotron, and to further cool them with an electron cooler. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The beam will be transported from ELENA to the experiments by an electrostatic transfer line, which is an elegant and cost effective solution at such low energies. The basic ELENA design including main performance limitations and expected beam characteristics and the project status including planning will be reported.

The Japan Proton Accelerator Research Complex, J-PARC, started its operation in 2008. The beam intensity from the accelerator has been improved a lot and active research activities have been carried out at the experimental facilities such as the Materials and Life Science Experimental Facility, the Neutrino Experimental Facility, and the Hadron Experimental Facility. In this talk, activities mainly at the Hadron Experimental Facility will be introduced as well as some prospects.

High-resolution x-ray spectroscopy of hadronic atoms will be performed with a cryogenic x-ray detector system based on an array of superconducting transition-edge-sensor (TES) microcalorimeters [1]. The spectrometer offers unprecedented full-width-at-half-maximum energy resolutions of 2 - 3 eV at 6 keV, which is about two orders of magnitude better than that of conventional semiconductor detectors. The 240 pixel spectrometer array will have a large collecting area of about 20 mm^2 thanks to recent technological advances in multiplexed readout of TES multi-pixel arrays. This will open a new door to investigate hadron-nucleus strong interactions and will also improve the precision of charged-hadron mass values. A hadronic atom is a Coulomb-bound system formed by a negatively charged hadron (e.g., pi^-, K^-, pbar, Sigma^-, Xi^-), electrons, and a nucleus. Effects of the strong interaction between the hadron and atomic nucleus are experimentally extracted from characteristic x-ray-emission spectroscopy of the most tightly bound energy levels that are the most perturbed by the strong force (e.g., [2-4] are recent measurements). Many kaonic-atom experiments have collected data on a variety of targets [5]; however, the energy resolution of the conventional semiconductor spectrometers employed in these experiments is insufficient to see the small spectral effects due to the strong interaction. As a result, the depth of the K^- - nucleus potential at zero energy remains unknown. This is closely related to the investigation of bound states of the kaon in the nucleus that is one of the hottest topics in strangeness nuclear physics now. Aiming at a breakthrough in this field, we are planning to perform ultra-high-resolution x-ray spectroscopy of kaonic atoms at J-PARC hadron beamline using arrays of TES microcalorimeters developed by NIST, which will be the first application of TESs to a hadronic atom experiment. Additionally, hadronic-atom x-ray spectroscopy has been used as a tool for measuring the charged hadron mass; we intend to improve the precision of the charged kaon mass measurement with TES spectrometers. In this talk we will give an overview of this project and discuss the recent progress. [1] C. Enss (ed.), Cryogenic Particle Detection, Topics in Applied Physics, vol. 99, Springer, 2005. [2] S. Okada et al., Phys. Lett. B 653 (2007) 387-391. [3] SIDDHARTA collaboration, Phys. Lett. B 697 (2011) 199-202. [4] SIDDHARTA collaboration, Phys. Lett. B 704 (2011) 113-117. [5] C.J. Batty, E. Friedman, A. Gal, Phys. Rep. 287 (1997) 385-445.

In our experiment the fine structure constant is deduced from the measurement of the recoil velocity of an atom when it absorbs a photon. Such a measurement is performed by combining a Ramsey-Bord\'e atom interferometer with Bloch oscillations. We obtain a value of $\alpha$ with a relative uncertainty of 6.6$\times$10${}^{-10}$\cite{Bouchendira}. Using this value of $\alpha$, we obtain a theoretical value of the electron magnetic moment in agreement with the experimental measurement of Harvard's group. The comparison of these values provides the most stringent test of QED. Moreover, the uncertainty is small enough to verify for the first time the muonic and hadronic contributions to the electron magnetic moment. In this talk we will discuss the latest developments of this experiment.

Since the first trapped antihydrogen in 2010 [1] and observing its long lifetime in the 0.5 K deep neutral atom trap [2], experiments have been performed on the anti-atom resulting in the observation of resonant transitions between the hyperfine states of the ground state [3], experimental limits on the ratio of the gravitational mass to the inertial mass of antimatter and an experimental limit on the charge of antihydrogen [5]. We will give an overview of the ALPHA experiment [6] and present some the results originating from recent experiments on trapped antihydrogen. Furthermore, a outline of a newly proposed antimatter gravity experiment will be given [7]. References [1] G. B. Andresen et al. (ALPHA collaboration), Nature 468, 673 (2010). [2] G. B. Andresen et al. (ALPHA collaboration), Nature Phys. 7, 558 (2011). [3] C. Amole et al. (ALPHA collaboration), Nature 483, 439 (2012). [4] C. Amole et al. (ALPHA collaboration), Nature Communications 4, 1785 (2013). [5] C. Amole et al. (ALPHA collaboration), Nature Communications 5, 3955 (2014). [6] C. Amole et al. (ALPHA collaboration), Nucl. Instr. and Meth. in Phys. Res. A 735 (2014) 319 [7] P. Hamilton et al., Phys. Rev. Lett. 112, 121102 (2014). *ALPHA collaboration http://alpha.web.cern.ch; C. Amole, M.D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P.D. Bowe, E. Butler, A. Capra, C.L. Cesar, M. Charlton, A. Deller, P.H. Donnan, S. Eriksson, J. Fajans, T. Friesen, M.C. Fujiwara, D.R. Gill, A. Gutierrez, J.S. Hangst, W.N. Hardy, M.E. Hayden, A.J. Humphries, C.A. Isaac, S. Jonsell, L. Kurchaninov, A. Little, N. Madsen, J.T.K. McKenna, S. Menary, S.C. Napoli, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, C. R. Shields, D.M. Silveira, S. Stracka, C. So, R.I. Thompson, D.P. van der Werf, J.S. Wurtele.

One of the fundamental properties of the proton and the antiproton is the spin magnetic moment µ_{p,p}. So far, the most precise value of the proton magnetic moment was based on spectroscopy of a hydrogen maser in a magnetic field [1]. Theoretical corrections at the level of 17.7 ppm were required to extract µp with a fractional precision of about 10ppb. Using a Penning trap with a superimposed magnetic inhomogeneity, the magnetic moment of the antiproton was measured with a fractional precision of 4.4ppm [2]. In our Penning trap experiments we aim at direct measurements of both values with fractional precisions at the ppb level, or better. The comparison of both values will provide a stringent test of CPT-invariance with baryons. Our measurements are based on the determination of a frequency ratio µ_p/µ_N = ν_L/ν_c, where µ_N is the nuclear magneton, and ν_L and ν_c the Larmor- and the cyclotron frequency, respectively. The cyclotron frequency is measured by image current detection, while the Larmor frequency is obtained by performing quantum jump spectroscopy in a magnetic inhomogeneity. This method has already been applied with great success in measurements of the electron/positron magnetic moments, however the (anti)proton magnetic moment is about 660 times smaller than that of the electron/position system which constitutes a significant challenge. To resolve proton spin quantum transitions a magnetic bottle of 300.000 T/m^2 is required [3]. This strong inhomogeneity limits experimental precision to the ppm level. Thus, we apply the so-called double Penning trap technique which separates the spin state analysis and the precision frequency measurement to two traps, an analysis trap and a precision trap, where the magnetic field is homogeneous. Recently we demonstrated this technique for the first time with a single proton [4] and based on this success we measured the proton magnetic moment for the first time directly[5]. Our first direct high-precision measurement of the proton magnetic moment is more than 760 times more precise than any direct measurement performed so far. The value is consistent with the currently accepted CODATA value, but 2.5 times more precise. To apply this method to the antiproton, we are currently constructing the BASE experiment at the antiproton decelerator of CERN. In the talk I will present our recent magnetic moment measurement and report on the status of both experiments. References [1] P.F. Winkler Phys. Rev. A 5, 83-114 (1972). [2] J. DiSciacca et al., Phys. Rev. Lett. 110, 130801 (2013). [3] S. Ulmer et al., Phys. Rev. Lett. 106, 253001 (2011). [4] A. Mooser et al., Phys. Lett. B 723, 78 (2013). [5] A. Mooser et al., Nature 509, 596 (2014).

Antihydrogen atoms are produced via laser controlled, two stage charge exchange in a cryogenic Penning trap. 5x10^6 antiprotons and 3x10^8 positrons are held in a nested well potential structure. Rydberg Cs atoms travel radially across the trap and through the positron plasma to produce Rydberg Positronium. The Ps* atoms are produced isotropically, with some atoms moving along the axis of the Penning trap and interacting with the cold antiprotons via a second charge exchange to form potentially very cold antihydrogen. Antihydrogen formation is detected by comparing the antiproton annihilation counts with the Cs excited to the Rydberg state to those obtained when the Cs remains in the ground state.

Many gravitational phenomena have been well tested with macroscopic matter composed of neutrons, protons, and electrons, but much remains unexplored. Gravitational interactions with other types of matter such as antimatter, charged matter, and matter beyond the first generation remain nearly untested. The gravitational Standard-Model Extension (SME) provides a test framework for the analysis of both traditional matter tests, as well as tests with new types of matter. This talk will provide a review of Lorentz and CPT violation and SME-based proposals for gravitational tests with a focus on novel sensitivities that may be achieved with exotic atoms.

The experiment AEgIS is currently taking data at AD. The experiment is aiming to form a cold antihydrogen beam to perform a direct measurement of the gravitational acceleration on antihydrogen and spectroscopic measurements. The goal, the preliminary achievements, the status and the perspectives of the experiment will be presented.

The GBAR project (Gravitational Behaviour of Antihydrogen at Rest) at CERN, will measure the free fall acceleration of ultracold neutral antihydrogen atoms in the terrestrial gravitational field. The experiment consists in preparing antihydrogen ions (one antiproton and two positrons) and sympathetically cool them with Be+ ions to a few 10 microK. The ultracold ions will then be photo-ionized just above threshold, and the free-fall time over a known distance measured. I will describe the project, the accuracy that can be reached by standard techniques, and discuss possible improvements using quantum reflection of antihydrogen on surfaces to use quantum methods of measurements.

This abstract covers recent results on two different topics: 1. New results for variation of the fine structure constant alpha based on the quasar absorption spectra data indicate the variation of alpha in space. The spatial variation can explain fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. There is an agreement between the results obtained using different telescopes and different redshifts. The astrophysical results may be used to predict the variation effects in laboratory experiments. The variation effects are strongly enhanced in highly charged ions. 2. Measurements and calculations of parity (P) violation in atoms and ions provide tests of the Standard model and limits on new physics. Atomic and molecular experiments can also be used to detect nuclear anapole moment - magnetic multipole which violates fundamental symmetries: parity (P) and charge conjugation (C). These measurements will give us the strength of parity violating nuclear forces and may provide new test of the Standard model. Measurements of time-reversal (T) violating interactions and electric dipole moments (EDM) in atomic and molecular experiments present a possibility to search for physics beyond the Standard model. Violation of the fundamental symmetries (P,T (EDM), Lorents) may also be produced by the primordial axion condensate created after Big Bang, and by other hypothetical cosmic fields. Limits on these fields may be obtained from current and new proposed experiments.

Atomic physics and hadron physics are both based on Yang Mills gauge theory; in fact, quantum electrodynamics can be regarded as the zero-color limit of quantum chromodynamics. I review a number of areas where the techniques of atomic physics provide important insight into the theory of hadrons in QCD. For example, the Dirac-Coulomb equation, which predicts the spectroscopy and structure of hydrogenic atoms, has an analog in hadron physics in the form of light-front relativistic equations of motion which give a remarkable first approximation to the spectroscopy, dynamics, and structure of light hadrons. The renormalization scale for the running coupling, which is unambiguously set in QED, leads to a method for setting the renormalization scale in QCD. The production of atoms in flight provides a method for computing the formation of hadrons at the amplitude level. Conversely, many techniques which have been developed for hadron physics, such as scaling laws, evolution equations, and light-front quantization have equal utility for atomic physics, especially in the relativistic domain. I also will present a new perspective for understanding the contributions to the cosmological constant from QED and QCD.

We describe recent results in laser spectroscopy of antiprotonic helium atoms carried out by the ASACUSA collaboration at CERN. We also briefly introduce an experiment which attempts to measure the resonance transitions of pionic helium atoms by laser spectroscopy for the first time.

In our recent work [1] we have calculated the relativistic Bethe logarithm contribution at order ma^7 in the two Coulomb center approximation. These results then have been used for improved calculations of the transition energies for the hydrogen isotope molecular ions and antiprotonic helium atoms. The general formula for the one-loop self-energy contribution at the ma^7 order has been obtained in [2]. Including other theoretical contributions in a nonrecoil limit at order ma^7, such as one-loop vacuum polarization, the Wichman-Kroll contribution, the complete two-loop contribution, etc, and the leading term of the ma^8 order one gets transition energies for the ro-vibrational transitions of the pbar-He with the relative uncertainty of ~4*10^{-11}. We show that our latest results make feasible determination of the electron-to-antiproton mass ratio mp/me using antiprotonic helium spectroscopy with a fractional precision 3.6*10^{-11}, while from the hydrogen molecular ions the electron-to-proton mass ratio may be determined with a relative uncertainty of 1.5*10^{-11}. [1] V.I. Korobov, L. Hilico, and J.-Ph. Karr, Phys. Rev. A 87, 062506 (2013). [2] V.I. Korobov, L. Hilico, and J.-Ph. Karr, Phys. Rev. Lett. 112, 103003 (2014); V.I. Korobov, L. Hilico, and J.-Ph. Karr, Phys. Rev. A 89, 032511 (2014).

On behalf of the PSI UCN Team and the nEDM collaboration Ultracold neutrons (UCN) can be stored in suitable vessels for hundreds of seconds and therefore serve as excellent probe for fundamental physics experiments, probing e.g. the properties of the neutron, gravity, extra forces, or other physics beyond the Standard Model scenarios. Such experiments have in common the need for high UCN intensities. At the Paul Scherrer Institute, Switzerland a new ultracold neutron source [1] was built. Based on superthermal UCN production in about 30 liters of solid deuterium at 5 K [2], UCN can be delivered to three beam ports in regular operation. Scientific proposals are now being invited. We will report on the characterization measurements, the achieved intensity improvements, and the experience gained in operating the UCN source. At the same time the experiment to search for a permanent electric dipole moment of the neutron (nEDM) [3] is being operated by an international collaboration. The present apparatus uses the setup which led to the best nEDM limit so far [4], but was afterwards substantially improved. Data-taking started in 2013. In parallel a new apparatus with two precession chambers is being developed aiming at another order of magnitude increase in sensitivity. We will report on the performance of our experiment, its status and give an outlook. References [1] B. Lauss, Hyperfine Interactions 211 (2012) 21-25. [2] K. Kirch et al., Nuclear Physics News 20, 1 (2010) 17. [3] C.A. Baker et al., Physics Procedia 17 (2011) 159-167. [4] C.A. Baker et al., Physical Review Letters 97 (2006) 131801.

Antihydrogen is the simplest stable antimatter atomic system consisting of an antiproton and a positron. A source of antihydrogen amendable to precision spectroscopic investigation would provide a sensitive direct test of CPT symmetry. To achieve this, the ASACUSA-Cusp collaboration has developed an antihydrogen beam which will be used for Rabi-like in flight spectroscopy measurements. Antihydrogen is formed within an unique anti-Helmholtz configuration cusped magnetic field which allows spin dependent focusing and hence, produces a spin-polarized beam. During mixing of positrons and antiprotons, 80 antihydrogen atoms have been observed 2.7 m downstream of the production region where perturbing magnetic fields are negligible. The absolute count rate for atoms with principal quantum number less than 43 was 0.04/s (during a mixing cycle). This result is a significant step towards the physics goal of the ASACUSA-Cusp experiment, the precision spectroscopy of the ground-state hyperfine structure of antihydrogen. [1] Kuroda, N. et al., A source of antihydrogen for in-flight hyperfine spectroscopy. Nature Communications 5 (2014) 3089.

Periodic time modulations were found recently in the measurements of the two-body orbital electron capture (EC) decay of hydrogen-like 140Pr58+ and 142Pm60+ ions stored and cooled in the Experimental Storage Ring (ESR). The modulations in both investigated systems can be characterized by periods TP near to 7 s and amplitudes a of about 20% [1]. The observed phenomenon caused intensive discussions in the physics community on its possible explanation. Numerous suggestions were proposed. However, no consensus is presently reached and the effect remains still unexplained. In the last years, a new Schottky detector has been developed [2], which allowed for an unambiguous determination of the EC decay-time of each individual stored and cooled parent ion, with a very high time accuracy of merely a few tens of milliseconds. The EC decay of H-like 142Pm60+ ions was re-investigated in the ESR by employing the previously used Schottky pick-up as well as this new detector [3]. The data recorded by both detectors confirmed that the exponential EC decay is modulated with a period TP =7.11(8) s (mean of both detectors), in full accordance with the modulation period TP = 7.10(25) s obtained for 142Pm60+ in the previous experiment. However, the mean modulation amplitude of both detectors of a = 12(2)%, although being statistically significant, is almost two times smaller than the one seen previously. Also the three-body β + decays of H-like 142Pm60+ ions has been analyzed in the new experiment. No significant modulation period could be observed. The nature of the modulated EC decays, if undoubtedly confirmed in future experiments, is still unclear and, since it might be related to physics beyond the Standard Model, it requires urgently additional experimental investigations and theoretical interpretation. In this presentation the present status of the experiment and future perspectives will be discussed in detail. [1] Yu. A. Litvinov et al., Phys. Lett. B664 (2008) 162 [2] F. Nolden et al., Nucl. Instr. Meth. A6 5 9 (2011) 69 [3] P. Kienle et al., Phys. Lett. B726 (2013) 638

Despite their long painful history dibaryon searches (where dibaryon means a baryon number $B=2$ state independently on the internal structure: genuine six-quark state/baryonic-molecule) have recently received new interest, in particular by the recognition that there are more complex quark configurations than just the familiar $q\overline{q}$ and $qqq$ systems. A resonance like structure recently observed in double-pionic fusion to deuteron, at $M=2.38GeV$ with $\mathrm{\Gamma }=70MeV$ and $I(J^p)=0(3^{+})$ meanwhile proved to be the so-called “inevitable dibaryon” $d^{\ast }$. To investigate its structure we have measured its decay branches into the $d{\pi }^0{\pi }^0$, $d{\pi }^{+}{\pi }^{-}$, $pp{\pi }^{-}{\pi }^0$, $pn{\pi }^0{\pi }^0$ and $pn$ channels by $pd$ and $dp$ collisions in the quasi-free reaction mode, utilizing the WASA detector setup at COSY. The $pn$ decay channel was measured by use of polarized deuterons in inverse kinematics. These new $np$ analyzing power data exhibit a pronounced resonance effect in their energy dependence. The SAID partial-wave analysis with inclusion of these data reveals a pole in the complex plane of the ${}^3{D}_3$ partial wave at $(2380\pm 10)MeV-i(40\pm 5)MeV$ in accordance with the $d^{\ast }$ resonance hypothesis. Further investigations on the internal structure of the $d^{\ast }$ dibaryon, the SU(3) multiplet companions as well as the mirror partners are expected to be done in near future. Supported by COSY-FFE (FZ Jülich).

Three-body hadronic models with separable pairwise interactions are formulated and solved to calculate resonance masses and widths of $L=0$ $N\mathrm{\Delta }$ and $\mathrm{\Delta }\mathrm{\Delta }$ dibaryons using relativistic kinematics. For $N\mathrm{\Delta }$, $I(J^P)=1(2^{+})$ and $2(1^{+})$ resonances slightly below threshold are found by solving $\pi NN$ Faddeev equations. For $\mathrm{\Delta }\mathrm{\Delta }$, several resonances below threshold are found by solving $\pi N\mathrm{\Delta }$ Faddeev equations in which the $N\mathrm{\Delta }$ interaction is dominated by the $1(2^{+})$ and $2(1^{+})$ resonating channels. The lowest $\mathrm{\Delta }\mathrm{\Delta }$ dibaryon resonances found are for $I(J^P)=0(3^{+})$ and $3(0^{+})$, the former agreeing well both in mass and in width with the relatively narrow ${\mathcal{D}}_{03}(2370)$ resonance observed recently by the WASA@COSY Collaboration. Its spin-isospin symmetric partner ${\mathcal{D}}_{30}$ is predicted with mass around 2.4 GeV and width about 80 MeV.

We report results from our recent precision measurement of pionic Sn atoms in RIBF. The presentation will include results from our pilot run in 2010 and our first production series of measurement in June 2014. We are presently preparing for a simultaneous measurement of 1s and 2s pionic states in 121Sn atom. The measurement is aiming at first measurement of 2s pionic state in Sn atom and will benefit in improving the systematic errors arising in the absolute energy scales. The results will improve the precision of the deduced quantities of chiral condensate at the normal nuclear density.

During last decade large samples of data have been collected on the production of the ground-state mesons in collisions of proton or deuteron beam with hydrogen or deuterium target. These measurements have been performed in the vicinity of the kinematical threshold where only a few partial waves in both initial and final state are expected to contribute to the production process. This simplifies significantly the interpretation of the data, yet still appears to be challenging due to the few particle final state systems with a complex hadronic potential. We will review experiments and phenomenology of the near threshold production of the eta and eta-prime mesons in the proton-proton and proton-deuteron collisions.

Experimental approaches to determine the real and imaginary part of the meson-nucleus potential will be described. The experiments have been performed with the Crystal Barrel/TAPS detector at the electron accelerator ELSA (Bonn) and the Crystal Ball/TAPS detector at MAMI (Mainz). Measuring the transparency ratio as well as the excitation function and momentum distribution for photo production of ω- and η’- mesons, we find that for the η’-meson the imaginary part of the potential is smaller than the real part. In case of the ω-meson we observe the opposite. This makes the etaprime meson a good candidate for the search for meson-nucleus bound states while no resolved ω-mesic states can be expected. The results are discussed and compared to theoretical predictions. An outlook on future experiments is given.

We have been working on a spectroscopy experiment searching for eta'-nucleus bound states at GSI. The binding of an eta' meson may arise from an attractive etaprime-nucleus interaction which leads to a mass reduction at finite density, as a result of partial restoration of chiral symmetry in association with the U_A(1) anomaly. The first experiment, GSI S-437, will take place in July and August, 2014. We will make use of the 12C(p,d) reaction; the ejectile deuterons will be momentum-analyzed by the fragment separator (FRS). Furthermore, we will upgrade the experimental setup at Super-FRS in the FAIR era, so as to improve the sensitivity. In this contribution, very preliminary results of the analysis of brand-new data will be reported. In addition, we will discuss future plans towards FAIR experiments.

The ASACUSA collaboration aims to measure the ground state hyperfine splitting of the antihydrogen atom, since this is a system where the CPT symmetry can be investigated with extremely high sensitivity. The principal idea is described in [1,2]. During the CERN LS1 shut down, antiprotons were not available. Therefore, a source of cold, polarized, and modulated atomic hydrogen has been constructed to enable comprehensive testing of the Rabi-like experimental setup consisting of a microwave spin flip cavity and superconducting sextupole magnet [3]. After shortly discussing the main components of the atomic hydrogen source and detector as well as the spectroscopy beamline I will present the latest experimental data, which allowed for a characterization of the focusing effect of the superconducting sextupole magnet and the resonance line shape of the spin flip cavity. Furthermore, a confirmation of the proposed measurement principle for the hyperfine splitting of antihydrogen was achieved by the determination of the ground state hyperfine splitting of atomic hydrogen with a precision on the 10 ppb level. References [1] E. Widmann et al., Hyperfine Interactions, 215, 1-8 (2013) [2] N. Kuroda et al., Nature Communications, 2089, 5 (2014) [3] C. Malbrunot et al., Hyperfine Interactions, (2014) DOI: 10.1007/s10751-014-1013-z

K- and eta nuclei J. Mares, A. Cieply, D. Gazda Nuclear Physics Institute, 250 68 Rez, Czech Republic E. Friedman, A. Gal Racah Institute, The Hebrew University, 91 904 Jerusalem, Israel This contribution reports on our recent calculations of K- and eta quasi-bound states in nuclear systems using subthreshold energy dependent Kbar-N and eta-N amplitudes [1-4]. Many-body K- nuclear systems were calculated within a chirally motivated meson-baryon coupled-channel model due to Cieply and Smejkal [5]. Self-consistent evaluations yield K- potential depths -Re$V_K$ of order 100 MeV. Dynamical polarization effects and two-nucleon absorption modes are discussed. The widths of all K- nuclear quasi-bound states are comparable or even larger than the corresponding binding energies, exceeding considerably the energy level spacing [2]. The strong energy dependence of the s-wave eta-N scattering amplitude was included self consistently in eta nuclear bound state calculations within several underlying eta-N models. Binding energies and widths of eta nuclear states were calculated for nuclei across the periodic table [3,4], including 25Mg for which some evidence was proposed in a COSY experiment [6]. [1] A. Cieply, E. Friedman, A. Gal, D. Gazda, J. Mares, Phys. Lett. B 702 (2011) 402; Phys. Rev. C 84 (2011) 045206. [2] D. Gazda, J. Mares, Nucl. Phys. A 881 (2012) 159. [3] E. Friedman, A. Gal, J. Mares, Phys. Lett. B 725 (2013) 334. [4] A. Cieply, E. Freidman, A. Gal, J. Mares, Nucl. Phys. A 925 (2014) 126. [5] A. Cieply, J. Smejkal, Nucl. Phys. A 881 (2012) 115. [6] A. Budzanowski et al (COSY-GEM Collab.), Phys. Rev. C 79 (2009) 012201(R).

The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DA$\mathrm{\Phi }$NE collider at LNF-INFN, which is fundamental to solve longstanding questions in the non-perturbative strangeness QCD sector. AMADEUS step 0 consisted in the analysis of 2004/2005 KLOE data, exploiting $K^{-}$ absorptions in $H$, ${}^{4}He$, ${}^{9}Be$ and ${}^{12}C$, leading to the first invariant mass spectroscopy study with low momentum in-flight negative kaons. With AMADEUS step 1 a dedicated pure Carbon target was implemented in the central region of the KLOE detector, providing a high statistic sample of pure at-rest $K^{-}$ nuclear interaction. We will show the results obtained in the analysis of the ${\mathrm{\Sigma }}^{+}{\pi }^{-}$ and ${\mathrm{\Sigma }}^0{\pi }^0$ (pure isospin 0) channels, intended to shed light on the controversial nature of the $\mathrm{\Lambda }(1405)$ state. The analysis of the $\mathrm{\Lambda }{\pi }^{-}$ channel, from which the measurement of the module of the isospin 1, S-wave non resonant transition amplitude ca be extracted for the first time, will be presented. The search for kaonic nuclear clusters, and the investigation of single versus multi nucleon absorption in correlated $\mathrm{\Lambda }p$ $\mathrm{\Lambda }d$ and $\mathrm{\Lambda }t$ pairs production will be shown.

We discuss the role of QCD symmetries and confinement in understanding eta and etaprime mesic nuclei. Eta and etaprime bound states in nuclei are sensitive to the flavour-singlet component in the meson. The bigger the singlet component, the more attraction and the greater the binding. Recent results on the etaprime mass in nuclei from the CBELSA/TAPS collaboration are very similar to the prediction of the Quark Meson Coupling model. In the model eta-etaprime mixing induces a factor of two enhancement of the eta-nucleon scattering length relative to the prediction with a pure octet eta, with real part about 0.8 fm.

An analysis of hadronic atoms data is known to be the best tool to extract information about hadronic scattering lengths [1,2]. In particular, the recent combined analysis of piH and piD data carried out within ChPT [2] resulted in a high accuracy extraction of the S-wave piN scattering lengths. While the situation in kaonic systems is in general more complicated due to the presence of inelastic channels a combined analysis of KN and KD data has a big potential to pin down the KN scattering lengths. In this talk we discuss the status of the theory for KD scattering within low-energy EFT. A special emphasis is put on the role of recoil effects which appear as one of the main sources of the theory uncertainty in the calculation. [1] J. Gasser, V. Lyubovitskij and A. Rusetsky, Phys. Rep. 456, 167 (2008) [2] V. Baru, C.Hanhart, M.Hoferichter, B.Kubis, A.Nogga and D. Phillips, PLB 694, 473 (2011); NPA 872, 69 (2011)

The observation of long-lived (metastable) states of pi+pi- atoms (A2pi ) opens the possibility to measure the energy difference between ns and np states and to determine the value of the combination 2a0 +a2 of S-wave pipi scattering lengths with isotope spins 0,2 in a model-independent way. This result, together with the A2pi lifetime measurement that provides the value |a0 -a2|, allows to get a0 and a2 separately using only pi+pi- atoms data. In this experiment the proton beam with momentum 24 GeV/c interacts with a Be target with thickness 100mm and generates A2pi in short-lived ns states. Passing through the target a fraction of A2pi interacts with Be-atoms and get exited into long-lived 2p, 3p, 4p... states. From the Be target more than 6% of A2pi come out to the vacuum in the long-lived states. For the short lived A2pi, with Lorenz factor 20, the decay lengths of 2S, 3S and 4S are in the interval between 0.017 and 1.1mm, while the metastable atoms in the states 2P, 3P and 4P have the decay lengths between 5.7cm and 44cm. After the Be target at a distance of 100mm, it was installed a Pt foil in which only long-lived atoms break up, generating pi+pi- pairs with small relative momentum Q in their c.m.s. In order to suppress the background from the pi+pi- generated in the Be target, a magnet with BL=0.023 Tm was installed between Pt foil and the target. At the exit of this magnet the pairs produced on the Be target have their Qy component increased of 12.7 MeV/c, while the pairs generated on Pt foil, have their Qy component increased only of 2.3MeV/c by the fringing magnetic field. In this report we present the results of the analysis which select pi+pi- pairs with small transverse component QT<1.5 MeV/c. The distribution in the longitudinal component QL of these pairs shows a peak around QL=0 MeV/c. The statistical significance of this peak is 5s and it could be explained by the long-lived pi+pi- atoms breaking in the Pt foil.

Baryonium understood here as a nucleon-antinucleon quasi-bound state was searched for at CERN in the days of LEAR. Nothing has been found, but broad states or states close to the threshold were not excluded. A convincing detection requires selective experiments. Such experiments offering more than scattering or crude absorption have been performed in recent years. These are of two kinds (1) decays J/ψ -> proton, antiproton, meson ( or photon ) [1] J/ψ -> several π mesons (2) level widths in the lightest antiprotonic atoms “cold capture” in some heavy antiprotonic atoms, [2] The selectivity in reactions (1) is due to definite initial state and CP invariance, the selectivity in reactions (2) may be obtained with fine structure resolution, so far available only in the H atom. Both decays (1) indicate existence of a broad S-wave, I= 0 structure which may be interpreted, at least on the basis of Paris N-N-bar potential, as a 50 MeV broad bound state denoted X(1835) by BES. Atomic X-ray experiments give some support for the effect of such state and indicate another 5 MeV wide P-wave quasi-bound state. Both these states find support in the Paris potential. This talk will review the data and concentrate on a model for decays (1), its applicability to the search of baryonium in few-N systems and formation of J/ψ in nuclei. There is a similarity in the search of baryonium with antiprotonic atoms and studies of Λ(1405) in K mesic atoms. I will try to discuss relations and possibilities. [1] J.Z.Bai for BES Collaboration. Phys.Rev.Lett. 91(2003) 02200. M. Ablikim for BES Collaboration, Phys.Rev.Lett. 95 (2005) 262001. J-P. Dedonder et al , Phys.Rev. C 80 (2009)0145207 [2] A. Trzcinska et al, Nucl. Phys. A 692