Poster (POS)

PANDA is an experiment for hadron spectroscopy which will be build in Darmstadt at the future site of FAIR. Main goals of the experiment are the search for new states and the precise measurement of the line shapes of known charmonium states with the energy scan method. To normalize measured data, precise knowledge of the luminosity is vital.
At the PANDA experiment the luminosity will be measured via the angular distribution of antiproton-proton elastic scattering. The luminosity detector will consist of 4 planes of silicon-pixel-sensors (HV-MAPS) to measure the track distribution of antiprotons depending on the scattering angle. The online reconstruction of the tracks will be performed on GPUs. After the tracks are reconstructed, only the data containing tracks will be saved for further processing while the rest gets discarded.
In this talk the status of the online track reconstruction and the data acquisition of the luminosity detector will be presented.

Simulation results of the feasibility studies of time-like proton electromagnetic form factors at PANDA (FAIR) are presented. The simulation was performed using the PandaRoot software framework in a wide $q^2$ range. The signal $\bar p p \to e^+ e^-$ and the background $\bar p p \to \pi^+ \pi^-$ channels have been studied using two different methods. Individual signal efficiency and background suppression techniques were applied to extract proton form factors. The statistical precision of the proton form factors extraction is determined. The results of two methods are consistent with each other. A number of systematic uncertainties have also been evaluated. The competitiveness of the PANDA experiment with existing data and planned experiments is presented.

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 $\bar{p} p \rightarrow \mu^{+} \mu^{-}$ 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 $p\bar{p}\rightarrow l^{+} l^{-}$, where l = e, $\mu$, 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. 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 $\bar{p} p \rightarrow \mu^{+} \mu^{-}$ will also serve as a consistency check of the TL em FF data from $\bar{p} p \rightarrow e^{+} e^{-}$. 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 $p \bar{p} \rightarrow \mu^{+} \mu^{-}$ at different antiproton beam momenta. The signal identification and the suppression of the main background process ($p\bar{p} \rightarrow \pi^{+} \pi^{-}$) are studied. The preliminary results at different beam momenta are presented.

Three algorithms, designed to search for clusters in the electromagnetic calorimeter (EMC) of the future PANDA experiment, are described and evaluated. The high rate of 2E7 interactions/s between the antiproton beam and the proton target leads to a high probability for pile-up and event mixing, complicating the search for clusters. To reduce the amount of data produced by the experiment, the detector will preprocess as much data as possible online, and select events of interest based on online reconstruction. To perform these reconstructions, input from the cluster finding algorithm, which is part of the online preprocessing, is essential. The algorithms are tested using simulated data for both their efficiency and processing time using two 5000 event data samples in the high rate
case, a lower rate case (factor 100 lower rate), and the case with completely disjoint events. The first sample is a low photon-multiplicity sample of direct two-photon production events. The efficiency, i.e. the number of successful reconstructions, is similar for all methods, around 90%. The algorithm that is most eligible for online usage runs the fastest, as expected. The second sample tests the high photon-multiplicity channel of the hc meson to 7 photons, and will also be expanded with background events. More detailed results on the performance evaluation will be presented.

The PANDA experiment, one of the four scientific pillars of the FAIR facility currently in construction in Darmstadt, Germany, is a next-generation particle detector that will study collisions of antiprotons with beam momenta of 1.5–15 GeV/c on a fixed proton target.

Because of the broad physics scope and the similar signature of signal and background events in the energy region of interest, PANDA's strategy for data acquisition is to continuously record data from the whole detector, and use this global information to perform online event reconstruction and filtering. A real-time rejection factor of up to 1000 must be achieved to match the incoming data rate for offline storage, making all components of the data processing system computationally very challenging.

Online particle track identification and reconstruction is an essential step, since track information is used as input in all following phases. Online tracking algorithms must ensure a delicate balance between high tracking efficiency and quality, and minimal computational footprint. For this reason, a massively parallel solution with multiple Graphic Processing Units (GPUs) is under investigation.

The Locus Circle Hough algorithm is currently being developed by our group. Based on the Circle Hough algorithm (doi:10.1088/1742-6596/664/8/082006), it uses the information from the geometric properties of primary track candidates in the Hough space to extend the hit-level parallelism to later phases of the algorithm. Two different strategies, based on curve rasterization and analytical intersections, are considered.

The poster will present the core concepts of the Locus Circle Hough algorithm, details of its implementation on GPUs, and results of testing its physics and computational performance.

The PANDA Experiment is planned to operate at the Facility for Antiproton and Ion Research (FAIR) which is currently under construction at Darmstadt. PANDA will address many key topics of hadron physics. The physics program requires a versatile detector system covering the full acceptance and the complete set of observables. For the core systems the technical design is complete. We collected conclusive data sets from prototype beam tests to complete the design of the particle identication detectors. First detector systems are already under construction.
To achieve its physics goals, PANDA has to face several challenges regarding detectors with a small material budget, high resolution, fast readout electronics and event selection. In this contribution a selection of systems are presented to illustrate how these challenges are met.
A radiation hard silicon vertex detector with self triggering hybrid pixels and micro-strips was developed for the precise determination of decay and interaction points. The design features a very small material budget and high readout speed.
Straw tubes that are operated with over-pressure to become self-supporting are employed as trackers in the magnetic eld. A very low mass design was achieved with this concept both for the tracking inside the solenoid magnet as well as around the dipole magnet.
Electromagnetic calorimetry with lead tungstate crystals is brought to its best performance at PANDA by operation at -25C and employing especially developed large area avalanche photo-diodes.
The principle of detection of internally reflected Cherenkov light (DIRC) is significantly improved in performance and compactness for the identication of charged particles and employed in two locations in the experiment.
Finally, the data acquisition (DAQ) is designed to select interesting events online without any hardwired trigger. This gives full flexibility to the experiment and makes it possible to program the DAQ for measurements of new physics channels not considered yet at the beginning.

PANDA Forward Spectrometer Calorimeter
The PANDA experiment is one of the challenging projects being constructed on new FAIR facility near Darmstadt. It will use the antiproton beam from the High Energy Storage Ring colliding with an internal proton target and a general purpose spectrometer to carry out a rich and diversified hadrons physics program. One of the main PANDA detectors is a calorimeter complex consisting of a central PWO crystal based calorimeter and a forward shashlyk-type sampling calorimeter. The design of the PANDA Forward Spectrometer Calorimeter (FSC) is completed and validated by several test-beam measurements. The FSC prototype performance based on test-beam measurements at Protvino and Mainz will be presented in the report. The construction of the PANDA detector has been started and planned to be completed before 2019. FSC Technical Design Report recently was submitted to FAIR experts committee and construction of the detector is expected to be started in the next year. The detector production-ready status including mass-production techniques developed at IHEP, Protvino is also presented in the report.

Abstract for a poster in DPG 2016 in Darmstadt

Please find in the document attached my proposed abstract for the DPG spring meeting.
I intend to prepare a poster.

Best regards,
Mamen.

The PANDA experiment is one of the pillars of the future Facility for
Antiproton and Ion Research (FAIR) in Darmstadt, Germany. The PANDA
physics program is focused on answering fundamental questions related to
Quantum Chromodynamics (QCD), mostly in the non-perturbative energy
regime. Spectroscopy exploiting D-mesons and Λ c -baryons that are com-
posed of a heavy charm valence quark and one or two light valence quarks
is an integral part of the PANDA physics program. Such systems can sys-
tematically provide information on various key features of QCD, such as
heavy-quark symmetry, chiral symmetry breaking, and the nature of exotic
states. In this work, the experimental feasibility of studying the production
mechanisms of associative open-charm hadrons in antiproton-proton anni-
hilations is investigated using Monte Carlo simulations. We present results
obtained for the channels p ̄ + p → D 0 D ̄ 0 and p ̄ + p → Λ + Λ − ,
highlighting the detector performances (efficiencies and resolutions) and the statistical
significance that can be achieved with the foreseen luminosities.