Search

We present the LOcal Track Finder (lotf) algorithm, a method that performs charged-particle trajectory reconstruction using the Straw Tube Tracker, one of the central trackers of the antiProton ANnihilation at DArmstadt (PANDA) detector. The algorithm builds upon the neighboring relations of the tubes to connect individual hits and form track candidates. In addition, it uses a local fitting procedure to handle regions where several tracks overlap and utilizes a system of virtual nodes to reconstruct the z-information of the particle trajectories. We generated 30,000 events to assess the performance of our approach and compared our results to two other track reconstruction methods. lotf has (1) an average of 85% of found tracks, (2) the largest number of Fully Pure tracks, (3) the lowest amount of incorrect reconstructions, and (4) is significantly faster than the other two approaches. Further, we tested our method using 3,750 data sets composed of 4 events each, showing that our approach handles cases in which events are mixed. The raw (without parallelization) average reconstruction rate is about 68,000 hits/s, which makes the present algorithm promising for online data selection and processing.

We present a detailed simulation study of the signatures from the sequential decays of the triple-strange pbar p -> {\Omega}+{\Omega}- -> K+{\Lambda}barK- {\Lambda} -> K+pbar{\pi}+K-p{\pi}- process in the PANDA central tracking system with focus on hit patterns and precise time measurement. We present a systematic approach for studying physics channels at the detector level and develop input criteria for tracking algorithms and trigger lines. Finally, we study the beam momentum dependence on the reconstruction efficiency for the PANDA detector.

The PANDA experiment at FAIR offers unique possibilities for performing hyperon physics. The detector will enable the reconstruction of both hyperon and antihyperon, which will be created together in proton-antiproton collisions. This enables investigations of the strong interaction in the non-perturbative regime. Due to their relatively long-lived nature, the hyperons impose a particular challenge on the track reconstruction and event building. In order to exploit the large expected reaction rates to the fullest, PANDA will utilize a fully software-based event filtering. Therefore, reconstructing hyperons for such a filter requires online track reconstruction that can handle particles created a measurable distance away from the interaction point and, at the same time, operate on free streaming data is needed. Until antiprotons are available at PANDA, a part of the hyperon program can be carried out with the predecessor, PANDA@HADES using a proton beam. In this thesis, investigations of the detector signatures from the decay channels Λ → pπ-, Ξ- → Λπ- and Ω- → Λ K- produced in → reactions are presented. The detector signatures guide the subsequent track reconstruction algorithms. A candidate for online track reconstruction algorithms on free streaming data based on a 4D Cellular Automaton has been developed and is benchmarked. It utilizes information from the PANDA straw tube tracker and is agnostic to the point of origin of the particle. The track reconstruction quality assurance procedure and results from the tracking at different event rates are also presented. Finally, extrapolation algorithms for including hit information from additional detectors in the tracks are outlined. In order to maximize the potential of the predecessor experiment PANDA@HADES, a kinematic fitting procedure has been developed for HADES that combines geometric the decay vertex information of neutral particles and track parameters such as momentum. Benchmark studies on simulated data from the channel p(3.5 GeV)p → ΛK+p are presented as well as tests of the kinematic fit on experimental data from 2007.

The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of hadron-, nuclear- and atomic physics experiments. The future antiProton ANnihilations at DArmstadt (PANDA or PANDA) experiment at FAIR will offer a broad physics programme, covering different aspects of the strong interaction. Understanding the latter in the non-perturbative regime remains one of the greatest challenges in contemporary physics. The antiproton-nucleon interaction studied with PANDA provides crucial tests in this area. Furthermore, the high-intensity, low-energy domain of PANDA allows for searches for physics beyond the Standard Model, e.g. through high precision symmetry tests. This paper takes into account a staged approach for the detector setup and for the delivered luminosity from the accelerator. The available detector setup at the time of the delivery of the first antiproton beams in the HESR storage ring is referred to as the Phase One setup. The physics programme that is achievable during Phase One is outlined in this paper. For complete list of authors see http://dx.doi.org/10.1140/epja/s10050-021-00475-y

This paper reports on Monte Carlo simulation results for future measurements of the moduli of time-like proton electromagnetic form factors, vertical bar G(E)vertical bar and vertical bar G(M)vertical bar, using the (p) over barp -> mu(+)mu(-) reaction at PANDA (FAIR). The electromagnetic form factors are fundamental quantities parameterizing the electric and magnetic structure of hadrons. This work estimates the statistical and total accuracy with which the form factors can be measured at PANDA, using an analysis of simulated data within the PandaRoot software framework. The most crucial background channel is (p) over barp -> pi(+)pi(-), due to the very similar behavior of muons and pions in the detector. The suppression factors are evaluated for this and all other relevant background channels at different values of antiproton beam momentum. The signal/background separation is based on a multivariate analysis, using the Boosted Decision Trees method. An expected background subtraction is included in this study, based on realistic angular distributions of the background contribution. Systematic uncertainties are considered and the relative total uncertainties of the form factor measurements are presented. For complete list of authors see http://dx.doi.org/10.1140/epja/s10050-020-00333-3

The study of baryon excitation spectra provides insight into the inner structure of baryons. So far, most of the world-wide efforts have been directed towards N * and Delta spectroscopy. Nevertheless, the study of the double and triple strange baryon spectrum provides independent information to the N * and Delta spectra. The future antiproton experiment (P) over bar ANDA will provide direct access to final states containing a (Xi) over bar Xi pair, for which production cross sections up to mu b are expected in (p) over barp reactions. With a luminosity of L = 10(31) cm(-2) s(-1) in the first phase of the experiment, the expected cross sections correspond to a production rate of similar to 10(6) events/day. With a nearly 4 pi detector acceptance, (P) over bar ANDA will thus be a hyperon factory. In this study, reactions of the type (p) over barp -> (Xi) over bar (+)Xi*(-) as well as (p) over barp -> (Xi) over bar*(+)Xi(-) with various decay modes are investigated. For the exclusive reconstruction of the signal events a full decay tree fit is used, resulting in reconstruction efficiencies between 3 and 5%. This allows high statistics data to be collected within a few weeks of data taking. For complete list of authors see http://dx.doi.org/10.1140/epja/s10050-021-00444-5Title in WoS: Study of excited Xi baryons with the (P)over-barANDA detector

High event rates of up to 20 MHz and continuous detector readout makes the event filtering at PANDA a challenging task. In addition, no hardware-based event selection will be possible due to the similarities between signal and background. PANDA is among a new generation of experiments utilizing a fully software-based event filtering. Currently, detector hits are often pre-sorted into events by the hardware filter before being passed to the software-based event filter with track reconstruction and event building. Track reconstruction will play a key part in the online filtering at PANDA where it will be used together with the event building. To ensure the quality of the track reconstruction, the existing quality assurance task has been modified to be able to cope with free streaming data. This talk will address the candidates for online track reconstruction algorithms for free streaming data based e.g. on the Cellular Automaton. The quality assurance procedure and the results from the tracking at different event rates and level of event mixing is presented.

This report concerns a detection module used for a pellet tracking system. Spheres of frozen hydrogen known as pellets can be used as internal targets in hadron physics experiments. Pellets are created some distance above the accelerator beam and directed in a pellet beam pipe to intersect the accelerator beam. To determine the position of a pellet in the interaction region in the case of an interaction, the pellets need to be tracked. This is done using tracking sections along the pellet beam pipe with measurement levels containing lasers illuminating the pellets and cameras, detecting the light. The pellet position in the interaction region can be reconstructed with an accuracy of 0.1 mm. To reach this accuracy there are high demands on the alignment of the cameras and lasers. Alignment by a pellet beam pipe is generally difficult so a solution enabling alignment elsewhere is desired. Therefore a detection module consisting of a plate with cameras and lasers mounted to it has been constructed. These cameras and lasers can be aligned in an alignment bench setup before being transported to a pellet beam pipe. The alignment of the cameras and lasers on the detection module must be maintained under certain conditions e.g. transportation, temperature changes, exposure to vibrations. This report covers investigations regarding the mechanical stability of the detection module under these conditions. Different alignment bench targets are investigated. The effects of the optics of the cameras and lasers and the functionality of the detection module are investigated.

The PANDA experiment will be one of the pillars of the new Facility for Antiproton and Ion Research (FAIR), which is currently under construction in Darmstadt, Germany. PANDA will be a fixed-target experiment which will allow the study of non-perturbative phenomena of the strong interaction. These will be probed in antiproton-proton collisions in the momentum range of 1.5 - 15 GeV/c. Within the PANDA physics program, strangeness production will be addressed through p ¯ p → Y ¯ Y processes. Measurements of the p ¯ p → ∑ ¯ 0 Λ channel for its comparison with the existing data of the Λ ¯ Λ channel are highly encouraged to study the role of isospin symmetry in hadron production dynamics. This work consists on a simulation study focusing on the feasibility of measuring the p ¯ p → ∑ ¯ 0 Λ channel at PANDA.

The purpose of this project was to analyze data from an experiment carried out at LNL (Legnaro National Laboratories) in order to test the collective nuclear model. In the experiment 170Dy was created by multi-nucleon transfer reactions. This isotope is predicted to be the most collective of all nuclei with A < 190. γ-ray energies originating from its deexcitation allow to measure its collectivity. The PRISMA spectrometer was used to determine which ions were produced in the reactions and AGATA measured the γ-radiation from these products. The analysis consists of a calibration process of all detectors and eventually leads to the identication of 170Dy and of its deexcitation energies. This report explains the analysis procedure and some of the steps to identify the reaction prodcuts and corresponding γ-ray energies were performed. Xe-isotopes and corresponding γ-spectra have been identied.