The PANDA Experiment at FAIR - Subatomic Physics with Antiprotons

The non-perturbative nature of the strong interaction leads to spectacular phenomena, such as the formation of hadronic matter, color confinement, and the generation of the mass of visible matter. To get deeper insight into the underlying mechanisms remains one of the most challenging tasks within the field of subatomic physics. The antiProton ANnihilations at DArmstadt (PANDA) collaboration has the ambition to address key questions in this field by exploiting a cooled beam of antiprotons at the High Energy Storage Ring (HESR) at the future Facility for Antiproton and Ion Research (FAIR) combined with a state-of-the-art and versatile detector. This contribution will address some of the unique features of PANDA that give rise to a promising physics program together with state-of-the-art technological developments.Comment: 8 pages, 2 figures, proceedings of MENU201

Experimental activities in few-body physics

Understanding the few-nucleon system remains one of the challenges in modern nuclear and hadron physics. Observables in few-nucleon scattering processes are sensitive probes to study the two and many-body interactions between nucleons in nuclei. In the past decades, several facilities provided a large data base to study in detail the three-nucleon interactions below the pion-production threshold by exploiting polarized proton and deuteron beams and large-acceptance detectors. Only since recently, the four-nucleon scattering process at intermediate energies has been explored. In addition, there is a focus to collect data in the hyperon-nucleon sector, thereby providing access to understand the more general baryon-baryon interaction. In this contribution, some recent results in the few-nucleon sector are discussed together with some of the preliminary results from a pioneering and exclusive study of the four-nucleon scattering process. Furthermore, this paper discusses the experimental activities in the hyperon sector, in particular, the perspectives of the hyperon program of PANDA.Comment: 9 pages, 4 figures, proceedings of the 21st European Conference on Few Body Problems in Physics, Salamanca, Spain, 30 August - 3 September 201

Studying the ω\omega-mass in-medium in γ+A→π0γ+X\gamma + A\to \pi^0\gamma +X reactions

Simulations based on a coupled-channel transport model have been performed to analyze the feasibility to study the in-medium $\omega$ mass exploiting the process $\gamma+A\to\pi^0\gamma+X$ for C, Ca and Nb nuclei. The distortions due to final-state interactions of the $\pi^0$ and background contributions from the reaction $\gamma+A\to\pi^0\pi^0+X$ are found to be small in the mass range of interest ($0.6<M_{\pi^0\gamma}<0.8$ GeV). Furthermore, the effect of the detector resolution on the $\pi^0\gamma$-mass determination is discussed

Observation of the Dalitz decay eta ' -&gt; gamma e(+)e(-)

We report the first observation of the Dalitz decay eta' -&gt; gamma e(+)e(-), based on a data sample of 1.31 billion J/psi events collected with the BESIII detector. The eta' mesons are produced via the J/psi -&gt; gamma eta' decay process. The ratio (eta' -&gt; gamma e(+)e(-))/Gamma (eta' -&gt; gamma gamma) is measured to be (2.13 +/- 0.09(stat) +/- 0.07(sys)) x 10(-2). This corresponds to a branching fraction B(eta' -&gt; gamma e(+)e(-)) = (4.69 +/- 0.20(stat) +/- 0.23(sys)) x 10(-4). The transition form factor is extracted and different expressions are compared to the measured dependence on the e(+)e(-) invariant mass. The results are consistent with the prediction of the vector meson dominance model