Study of the pd→3HeK+K−pd\to ^3\textrm{He} K^+K^- and pd→3Heϕpd\to ^3\textrm{He} \phi reactions close to threshold

Two--kaon production in proton--deuteron collisions has been studied at three energies close to threshold using a calibrated magnetic spectrograph to measure the final $^3$He and a vertex detector to measure the $K^+K^-$ pair. Differential and total cross sections are presented for the production of $\phi$--mesons, decaying through $\phi\to K^+K^-$, as well as for prompt $K^+K^-$ production. The prompt production seems to follow phase space in both its differential distributions and in its energy dependence. The amplitude for the $pd\to ^3${He}$\phi$ reaction varies little for excess energies below 22 MeV and the value is consistent with that obtained from a threshold measurement. The angular distribution of the $K^+K^-$ decay pair shows that near threshold the $\phi$--mesons are dominantly produced with polarization $m=0$ along the initial proton direction. No conclusive evidence for $f_0(980)$ production is found in the data.Comment: 13 figure

Experimental study of the pd(d p) → 3 He ππ reactions close to threshold

New experimental data on the pd → 3 He π+π− reaction obtained with the COSY-MOMO detector below the three-pion threshold are presented. The reaction was also studied in inverse kinematics with a deuteron beam and the higher counting rates achieved were especially important at low excess energies. The comparison of these data with inclusive pd → 3 He X0 rates allowed estimates also to be made of π0π0 production. The results confirm our earlier findings that, close to threshold, there is no enhancement at low excitation energies in the π+π− system, where the data seem largely suppressed compared with phase space. Possible explanations for this behavior, such as strong p waves in the π+π− system or the influence of two-step processes, are explored

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

P10 Physical exercise in major depressive disorder: effects on neuroplasticity, cognition and clinical symptoms

Brüchle W, Schwarzer C, Berns C, et al. P10 Physical exercise in major depressive disorder: effects on neuroplasticity, cognition and clinical symptoms. Clinical Neurophysiology. 2019;130(8):e149-e150