Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel $\bar p p \to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, $\textit{i.e.}$ $\bar p p \to \pi^+ \pi^-$, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

Measurements of h_c(^1P_1) in psi' Decays

We present measurements of the charmonium state $h_c(^1P_1)$ made with 106M $\psi'$ events collected by BESIII at BEPCII. Clear signals are observed for $\psi'\to\pi^0 h_c$ with and without the subsequent radiative decay $h_c\to\gamma\eta_c$. First measurements of the absolute branching ratios $\mathcal{B}(\psi' \to\pi^0 h_c) = (8.4 \pm 1.3 \pm 1.0) \times 10^{-4}$ and $\mathcal{B}(h_c \to \gamma \eta_c) = (54.3 \pm 6.7 \pm5.2)$ are presented. A statistics-limited determination of the previously unmeasured $h_c$ width leads to an upper limit $\Gamma(h_c)<1.44$MeV (90% confidence). Measurements of $M(h_c) = 3525.40 \pm 0.13 \pm 0.18$MeV/$c^2$ and $\mathcal{B}(\psi'\to \pi^0 h_c) \times \mathcal{B}(h_c \to \gamma\eta_c) = (4.58 \pm 0.40 \pm 0.50) \times 10^{-4}$ are consistent with previous results.Comment: 5 pages, 1 figure, accepted for publication in Physical Review Letter

Technical Design Report for the: PANDA Micro Vertex Detector

This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined.Comment: 189 pages, 225 figures, 41 table

New developments of the PANDA Disc DIRC detector

The DIRC principle (Detection of Internally Reflected Cherenkov light) allows a very compact approach for particle identification detectors. The PANDA detector at the future FAIR facility at GSI will use a Barrel-DIRC for the central region and a Disc DIRC for the forward angular region between 5◦ and 22◦ . It will be the first time that a Disc DIRC is used in a high performance 4π detector. To achieve this aim, different designs and technologies have been evaluated and tested. This article will focus on the mechanical design and integration of the Disc DIRC with respect to the PANDA environment