DPG (DPG)

see uploaded abstract

Due to the lack of experimental data, our knowledge on the excitation spectrum of double-strange baryons is very poor, however very important for understanding QCD in the non-perturbative regime. While within SU(3) symmetry the Xi spectrum should have as many states as the N and Delta spectrum together, only few Xi* states are established, most of them without spin-parity assignment. Thanks to the pbar-p entrance channel and the large detector acceptance for both charged and neutral particles, the PANDA experiment is the ideal place for Xi spectroscopy. An important part of the PANDA physics program is therefore devoted to the study of the Xi spectrum. Results of feasibility studies of identifying Xi* states in the final states Xibar+ L K-, Xibar+ Xi- pi0, and Xibar+ Xi- pi+ pi- will be reported, and the perspective of studying further decay modes will be discussed.

One of the most interesting fields in modern high energy physics is
the experimental study of quantum chromodynamics. The PANDA-
experiment at FAIR aims to explore this field by probing hadrons with
unprecedented precision and sensitivity. It will use proton-antiproton
collisions to reach center-of-mass energies of up to 5.5 GeV. Combined
with a high luminosity, this will make the detection of exotic resonances
with tiny cross sections feasible. In order to support the experiment
with simulations, the software framework PANDARoot was developed.
In this talk, the reconstruction of a hybrid candidate in the charmo-
nium sector with PANDARoot will be presented. The decay channel
involving the hybrid candidate ultimately decays into seven photons,
which makes it an excellent candidate to evaluate the performance of
the electromagnetic calorimeter. While seven photons already create
immense combinatorical background within the signal channel, there
exist at least four background channels with a very similar decay pat-
tern. Hence it is important to maximize the statistical significance of
the signal. For this, different optimization algorithms were evaluated,
where a genetic algorithm was found to be the most suitable one. Its
features and performance will be discussed. This project is supported
by BMBF and HIC for Fair.

The Barrel DIRC (Detection of Internally Reflected Cherenkov light) detector will be an essential part of the hadronic PID system of the PANDA experiment at GSI, Darmstadt. Covering the polar angle range of 22-140 degrees, it will provide pion-kaon separation power of at least 3 standard deviations for a charge particle momenta between 0.5 GeV/c and 3.5 GeV/c.
The design of the Barrel DIRC features the narrow bar radiator made from synthetic fused silica, a complex multi-layer spherical lens focusing system, a prism-shaped fused silica expansion volume, and MCP-PMTs (MicroChannel-Plate PhotoMultiplier Tubes) to detect the location and arrival time of the Cherenkov photons. All components were tested and successfully validated with a sophisticated prototype in a mixed hadron particle beam at CERN during 2015-2017. Additional test was conducted at CERN in 2018 with a purpose to optimize the number of used MCP-PMTs. Result of the optimization with the analysis and a comparison to the Geant4 simulation will be presented.

Within the FAIR phase-0 project, the use of FAIR equipment at
other facilities before the completion of the civil construction is envis-
aged. The PANDA EMC is a good candidate for FAIR phase-0, due
to the advanced state of its development. In particular, the backward
endcap (BWEC) of the PANDA EMC, which is developed and built at
HIM in Mainz, could be ready by 2020, three years before its foreseen
installation. Therefore, possible experiments at the MAMI electron
beam facility making use of the BWEC are under consideration.
One candidate is the measurement of the π electromagnetic transition
form factor via the electroproduction on a nuclear Coulomb field. To
select this channel, the momentum distribution of the π needs to be
measured by detecting the decay γ particles in an EMC.
Since the relevant γ s are emitted at forward angles, where high par-
ticle fluxes are expected, the affordable luminosity is limited by the
maximum event rate of the detector. Therefore, the total event rate at
different scattering angles with various targets need to be determined.
Monte Carlo simulations are ongoing and a beam test with a prototype
calorimeter was scheduled for January 2018 in order to address these
questions. The status of these feasibility studies will be presented.

We describe the technical layout and the expected performance of the
Barrel Time-of-Flight detector (Barrel TOF) for the PANDA target
spectrometer, giving updates on recent developments. The Barrel TOF
detector has been designed to precisely measure the time at which a
charged particle transits the detector with a resolution superior to the
other sub-detectors. It will signal the topology of physics events, hence
setting cornerstones for event classification. The implementation of the
Barrel TOF is based on very fast organic scintillator tiles coupled to
Silicon Photomultipliers. In total 2000 scintillators and 16k SiPMs will
be used, covering 5 m2. The detector R&D is now in advanced stage
and the technical design report is being reviewed by FAIR council.
The emphasis of this talk will be put on the updated design and
performance of the PCB stripline transmission and fine scans of the
time resolution of the detector elements, continuing the updates for
the B-TOF detector.

The electromagnetic target calorimeter (EMC) \cite{EMC} of the future $\overline{P}ANDA$ detector has the challenging aim to detect high energy photons with excellent energy resolution from 15 GeV down to a few tens of MeV. To reach this goal, improved PbW0$_4$ scintillator crystals, cooled down to $-25^\circ C$ have been chosen. They provide a fast decay time for highest count rates, short radiation length for compactness, improved light yield for lowest thresholds and excellent radiation hardness. The target calorimeter itself is divided into into a barrel and two endcaps. The individual crystal will be read out with two precisely matched large area avalanche photo sensors (APD). In the very inner part of the forward encap vacuum phototetrodes will be used instead.

In this talk the construction and assembly status will be presented. This includes for example the assembly of detector subunits, mechanical support structure, the cooling system, optical monitoring system and front end electronics.

This project is supported by the BMBF.