The present thesis comprises two parts, in the first part a data sample of 1.31 billion J/ψ events recorded by the BESIII experiment has been used to analyze the hadronic decay J/ψ → φηη and in the second part calibration measurements of the temperature monitoring system for the electormagnetic calorimeter of the PANDA target spectrometer are evaluated. Events of this decay pattern J/ψ → φηη with a final state consisting of a pair of charged kaons and four photons have been selected with an efficiency of about 12.5%. A partial wave analysis was performed with the PAWIAN softwarte and the information criteria BIC and AIC were used in an iterative approach to determine the hypotheses which optimally describe the data. The dynamics of scalar contributions are parameterized by a K-matrix with fixed pole positions and coupling strengths according to previous measurements. Utilizing Breit-Wigner functions to parameterize the dynamics of all other resonances, the hypothesis consisting of a (ππ) S-wave contribution as well as f2'(1525), f2(1810), ω2(1975), φ(1690), and h1(2215) resonances yields the best results. Additionally, hypotheses which use a K-matrix with released pole positions and coupling strengths to parameterize the dynamics of tensor contributions are tested. Scattering data from different measurements are used to constrain the K-matrix to reasonable parameter values. The best result is obtained for the hypothesis consisting of a K-matrix with three poles, (ππ) S-wave, ω2(1975), φ(1680), and h1(1965) contributions. Product branching fractions are determined for all contributions, most of them for the first time. For the f2'(1525) resonance, the branching fraction B(J/ψ → φ f2'(1525)) = (10.5 ± 0.6 stat ± 2.3 sys ) · 10^−4 is obtained, which is compatible with the result obtained by DM2 but not with the only other published value obtained by MARKII. The electromagnetic calorimeter of the PANDA detector, which is currently under construction and will start data taking in 2025, is based on lead tungstate crystal scintillators. The operating temperature is chosen to be −25 °C in order to increase the light yield. To ensure the envisaged energy resolution, the temperature must be regulated precisely and monitored with a relative accuracy of 0.02 °C. Customized sensors and dedicated readout electronics have been developed to fulfill the strong requirements and are produced at Ruhr-Universität Bochum. Within the scope of this thesis numerous instances of both sensors and electronics have been calibrated to obtain an accurate readout chain. The hysteresis effect of the temperature sensors is taken into account by fitting the corresponding subsamples separately. The RMS of the differences between these fits and the data typically yields 0.01 °C. The typical hysteresis at −25 °C amounts to 0.03 °C. Several dedicated measurements have been performed to characterize the hysteresis effect. Furthermore, measures are taken to increase the production rate of accurate and reliable sensors and to obtain a high calibration throughput. The readout electronics, called THMP, is designed modularly so that it can read out several kinds of sensors, in particular resistance temperature sensors. Evaluating the calibrations of 10 devices with 64 readout channels each, a typical resistance uncertainty of 4 mΩ is determined, which is by a factor of two better than the design requirement. The reproducibility of the THMP calibrations is in the order of the requirement.

Report of the FAIR Progress and Cost Review Board: Detailed Review of Progress and Financial Status of the FAIR Project 29 April 2019

\panda\ at FAIR will address the physics of strangeness in nuclei by several novel and unique measurements. These studies are only made possible by the one-of-a-kind combination of the stored antiproton beam at FAIR and the modular \panda\ detector which will be complemented by a germanium detector array. The latter was made available by a cooperation with the NUSTAR collaboration. \begin{itemize} \item \panda\ also offers the unique possibility to search for X-rays from very heavy hyperatoms such as e.g. $\Xi^-$-$^{208}$Pb. This will complement experiments at J-PARC which attempt to measure X-rays in light and (possibly) medium-heavy nuclei by the J-PARC E03 and E07 experiments. The measurement at \panda\ will allow to constrain the real and imaginary potential of $\Xi^-$ hyperons in the neutron skin of the lead nucleus. \item \panda\ will extend the studies on double hypernuclei by performing for the first time high resolution $\gamma$-spectroscopy of these nuclei. Thus, \Panda\ complements measurements of ground state masses of double hypernuclei in emulsions at J-PARC conducted by the E07 Collaboration \cite{E07-proposal,doi:10.1142/9789814618229_0025} or the production of excited resonant states in heavy ion reactions which may, for example, be explored in future by the CBM Collaboration. Together, these measurements will provide a as yet unrivaled information on the structure of double $\Lambda\Lambda$ hypernuclei. \item Furthermore, the exclusive production of hyperon-antihyperon pairs close to their production threshold in $\Pap$ - nucleus collisions offers a unique and hitherto unexplored opportunity to elucidate the behaviour of antihyperons in cold nuclei which is intimately related to the short-range part of the baryonic interaction. \end{itemize} In all these studies, the production of low momentum {\PagL} within nuclei or slow $\Xi^-$ hyperons which can eventually be stopped in a secondary target material play an essential role.