In the future hadron facility FAIR the HESR ring will supply antiprotons in the momentum range 1.5-15 GeV/c as projectiles for charm, strangeness and Form Factor physics. For all the reactions it will be necessary to use internal targets and in particular, for the double strangeness production, a solid 12C target will be used. Inserting a solid target inside an antiproton ring creates two main problems: a large background on the detectors due to the overwhelming amount of annihilations and a strong depletion of the beam due to all the hadronic and Coulomb interactions of the antiprotons with the 12C nuclei. The width of the target plays a crucial role in minimizing these unwanted eects. Two wire-shaped prototypes have been already realized, starting from a thin diamond disk. The wire shape has been obtained by using a femto-edge laser. One prototype has been submitted to irradiation by protons of 1.5 MeV and to simultaneous Back-Scattering control to test the impurity level, the surface 12C density, the radiation hardness and eventual phase modications during irradiation. Both the prototypes have been submitted to Micro-Raman spectroscopy in order to scan the carbon phases along the width. The results show performances which satisfy the experimental requirements.

Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion ($\pi N$) TDAs with the future \={P}ANDA detector at the FAIR facility. At high center of mass energy and high invariant mass of the lepton pair $q^2$, the amplitude of the signal channel $\bar{p}p \to e^+e^- \pi^0$ admits a QCD factorized description in terms of $\pi N$ TDAs and nucleon Distribution Amplitudes (DAs) in the forward and backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring $\bar{p}p \to e^+e^- \pi^0$ with the \={P}ANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, {\it i.e.} $\bar{p}p \to \pi^+\pi^- \pi^0$ were performed for the center of mass energy squared $s = 5$ GeV$^2$ and $s = 10$ GeV$^2$ , in the kinematic regions $3.0 < q^2 < 4.3$ GeV$^2$ and $5 < q^2 < 9$ GeV$^2$, respectively, with a neutral pion scattered in the forward or backward cone $| \cos\theta_{\pi^0}| > 0.5 $ in the proton-antiproton center of mass frame. Results of the simulation show that the particle identification capabilities of the \={P}ANDA detector will allow to achieve a background rejection factor of $10^8$ while keeping the signal reconstruction efficiency at around $40\%$ and that a clean lepton signal can be reconstructed with the expected statistics corresponding to $2$ fb$^{-1}$ of integrated luminosity. The future measurement of the signal channel cross section with \={P}ANDA will provide a new test of perturbative QCD description of the novel class of hard exclusive reactions and will open the possibility of experimentally accessing $\pi N$ TDAs.