No abstract available

[en] In this contribution the latest status of the feasibility studies for the measurement of time-like proton electromagnetic form factors (FF's) using reactions of the type anti pp → μ⁺μ^- at the PANDA experiment at FAIR is presented. Electromagnetic form factors are fundamental quantities which parameterize the electric and magnetic structure of hadrons. In the time-like region, the FF's can be accessed through reactions of the type p anti p → l⁺l^-, where l = e, μ, under the assumption of one photon exchange. It is the first time that muon pairs in the final state are used for the measurement of the TL em FF's of the proton. One advantage of using this channel is that radiative corrections due to final state radiation are suppressed by the heavy mass of the muon. Measuring anti pp → μ⁺μ^- also serves as a consistency check of the TL em FF data from anti pp → e⁺e^-. In frame of the PANDARoot software, which encompasses full detector simulation and event reconstruction, the statistical precision at which the proton FF's will be determined at PANDA is estimated for the signal reaction p anti p → μ⁺μ^- at different antiproton beam momenta. The signal identification and the suppression of the main background process (p anti p → π⁺π^-) are studied. For the analysis of the processes of interest, different methods have been used and are compared.

[en] One of the main goals of the future PANDA experiment at FAIR (Darmstadt, Germany) is the investigation of the proton structure. Electromagnetic form factors (FF's) are fundamental quantities which parameterize the electric and magnetic structure of hadrons. In the time-like region, proton FF's can be accessed experimentally in anti pp → l⁺l^- (l = e,μ) annihilation processes, assuming that the interaction takes place through the exchange of one virtual photon. The expected statistical precision for the measurement of time-like electromagnetic proton form factors with PANDA was investigated in the framework of the PANDARoot software for detector simulation and event reconstruction for both muon and electron channels. These studies investigated the possibility to achieve an optimal signal-background separation and sufficient background suppression of the relevant background channels. Different methods have been used to generate and analyse the processes of interest. The results show, that time-like electromagnetic proton form factors can be measured at PANDA with high statistical accuracy over a large kinematical region.

[en] The measurement of the time-like electromagnetic form factors (TL em FF), G_E and G_M, using reactions of anti pp → l"+l"- (l=e,μ) gives access to the structure of the proton. It will be the first time measurement of TL em FF of the proton accessing the muons in the final state. One advantage of using this channel is that radiative corrections due to final state radiation are suppressed by the heavy mass of the muon. Measuring anti pp → μ"+μ"- will also serve as a consistency check of the TL em FF data from anti pp → e"+e"-. Feasibility studies for the individual extraction of G_E and G_M out of the measured angular distribution are in progress for the muonic channel using the software package PANDARoot. Due to the strong hadronic background, mainly reactions of anti pp → π"+π"-, a very good signal-to-background separation is needed. For the analysis of both signal and background channel different multivariate classification methods are used. The current status of the studies is presented.

[en] The PANDA experiment at the upcoming FAIR accelerator facility will study antiproton annihilation reactions at antiproton beam momenta from 1.5 GeV/c up to 15 GeV/c. The PANDA homogeneous electromagnetic calorimeter has been designed to meet the physics goals of the PANDA experiment. The calorimeter consists of lead tungstate (PbWO₄) crystals and ensures an efficient photon/electron detection in a wide range of energy with a high resolution. In order to achieve the required energy resolution of the electromagnetic calorimeter, the individual crystal channels have to be calibrated and their radiation damage must be monitored and recovered. An optical fiber distribution system has been developed for the backward end-cap of the PANDA electromagnetic calorimeter. The optical prototype system provides light uniformity better than 95% which enable us to precisely calibrate the crystals. In this contribution, a description of the technical design and the performance of this prototype is presented.

[en] The PANDA detector at FAIR will be used to study interactions of antiprotons in a fixed target experiment. The electromagnetic calorimeter (EMC) of the target spectrometer, consisting of >15,000 PWO crystals, with its expected excellent performance and efficiency, will be one of the central components to achieve the physical goals. A first prototype for the Backward End-Capt (BWC) containing 16 crystals has been build and tested during 3 days of beamtime. The test was done with tagged photons in an energy range from about 50 MeV to 700 MeV at the Mainzer Microtron (MAMI). The prototype was designed to be as close as possible to the final desing of the BWC. This talk gives a short introduction in the design of the prototype and the latest updates, followed by a presentation of the results from the beam time. It describes the data analysis and the extraction of the energy resolution.

[en] This contribution presents the current status of the feasibility studies for the measurement of time-like proton electromagnetic form factors (FF's) using reactions of the type anti pp → μ⁺μ^- at the PANDA experiment at FAIR. Electromagnetic form factors are fundamental quantities which parameterize the electric and magnetic structure of hadrons. In the time-like region, the FF's can be accessed through reactions of the type anti pp → l⁺l^-, where l = e, μ, under the assumption of one photon exchange. It will be the first time that muon pairs in the final state will be used for the measurement of the TL em FF's of the proton. In frame of the PANDARoot software, which encompasses full detector simulation and event reconstruction, the statistical precision at which the proton FF's will be determined at PANDA is estimated for the signal reaction anti pp → μ⁺μ^- at different antiproton beam momenta. The signal identification and the suppression of the main background process (anti pp → π⁺π^-) are studied. The preliminary results at different beam momenta are presented.

[en] The PANDA experiment at the upcoming FAIR accelerator facility will study antiproton annihilation reactions at antiproton beam momenta from 1.5 GeV/c up to 15 GeV/c. With its modular multi purpose detector system it will be able to observe a variety of physics channels. The electromagnetic process group (EMP) at HI-Mainz is developing the backward end-cap of the electromagnetic calorimeter. Within this activity a method for the real time extraction of specific signal features using the APFEL ASIC preamplifier will be developed for the whole PANDA calorimeter. It has to recognise the signal pulse shape whilst ensuring at the same time a single channel threshold for deposited energy of lower than 3 MeV for meet the PANDA requirements. The extraction procedure need to be optimised in terms of resource usage in view of the many read out channels. The talk discusses the feature extraction with emphasis for its efficient implementation on a FPGA via distributed arithmetics.

[en] In view of the current FAIR construction schedule on the one side and the state of development of some FAIR experiment setups on the other side, the so-called ''phase-0'' of the FAIR project has been proposed, within which FAIR equipment shall be used for physics experiments at other facilities before the actual start of FAIR. The PANDA electromagnetic calorimeter (EMC), which is essentially already in the construction phase, can certainly be considered for such projects. In this talk, the use of the backward endcap of the PANDA EMC at the MAMI electron accelerator in Mainz is explored. The physics channels which have been proposed are presented and some feasibility issues are discussed.

[en] The PANDA (Antiproton Annihilation at Darmstadt) spectrometer, located at the Facility for Antiproton and Ion Research (FAIR), is an excellent tool for exploring the nucleon structure. An unpolarized target allows the determination of the electromagnetic time-like form factor of the proton. An additional experiment in which the target is transversely polarized is necessary for the first-time extraction of their imaginary part. A transverse polarization requires the shielding of the 2 T longitudinal field from the PANDA-Solenoid at the target volume and an additional transverse holding field. We present results from our first experiment at the Institut fuer Kernphysik in Mainz on intense magnetic flux shielding using a BSCCO (bismuth strontium calcium copper oxide) thin-wall hollow cylinder at 4.2 K and a 1.4 T external magnetic field and compare this to numerical calculations.