Conference (CON)

The PANDA experiment in preparation to be setup at FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany will cover many important aspects of hadron physics with cooled anti-proton beams of unprecedented intensity and precision in the momentum range between 1.5 and 15 GeV/c. The versatile detector is designed to address a rich physics program. This includes spectroscopy of QCD bound states ranging from charmonium to states composed of light quarks only, which comprises studies of the recently and yet not understood X, Y, and Z states and searches for other exotics. Production of hyperons will shed further light on the strong interaction in the intermediate region between the perturbative and non-perturbative regime. Time-like nuclear form factors and properties of hadrons in medium will be accessible and round up the experimental program. In this talk aspects of the PANDA physics program will be highlighted. Major components of the detector are under construction. The current status of the experiment will be presented.

**** Canceled ***** PANDA is a planned experiment at FAIR (Darmstadt) with a cooled antiproton beam in a range [1.5; 15] GeV/c, allowing a wide physics program in nuclear and particle physics. Gluonic excitations and the physics of hadrons with strange and charm quarks will be accessible with unprecedented accuracy, thereby allowing high precision tests of the strong interaction. Among other interesting physics processes, a systematic study of the DsJ(*) mesons is planned, with particular attention to the Ds0*(2317) and Ds1(2460), as their mass is found well below potential model predictions, despite to the others cs-bound systems in the charm-strange spectrum. This suggests that the same mechanism deflates both masses, leading to different interpretations. The width measurement is crucial to discriminate among theoretical models. The feasibility study of the ppbar ---->Ds Ds0*(2317) and the ppbar ---->Ds Ds1(2460) processes are presented, using the current status of the PandaRoot framework development, together with theoretical prediction of the cross section calculation and background prediction, based on full simulations. The minimum momentum required to run such a simulation is p>8.8 GeV/c. With a beam momentum resolution Dp/p ~ 10-4, PANDA will be able to achieve a factor 20 higher mass resolution than attained at the B-factories, which is expected to be decisive on these and second-order open questions.
The technique to evaluate the width from the excitation function of the cross section of the Dsj(*) mesons is presented, as a unique feature to disclose their nature.

"PANDA is a planned experiment at FAIR (Darmstadt) with a cooled antiproton beam in a range [1.5; 15] GeV/c, allowing a wide physics program in nuclear and particle physics. It is the only experiment worldwide, which combines a solenoid field (B=2T) and a dipole field (B=2Tm) in an experiment with a fixed target topology, in that energy regime. The tracking system of PANDA involves the presence of a high performance silicon vertex detector, a GEM detector, a Straw-
Tubes central tracker, a forward tracking system, and a luminosity monitor. The offline tracking algorithm is developed within the PandaRoot framework, which is a part of the FairRoot project.
The tool here presented is based on algorithms containing the Kalman Filter equations and a deterministic annealing filter. This general fitting tool (genfit2) offers to users also a Runge-Kutta track representation, and interfaces with Millepede II (useful for alignment) and RAVE (vertex finder). It is independent on the detector geometry and B field map, and written in C++ o.o. modular code. Several fitting algorithms are available with genfit2, with user-adjustable parameters; therefore the tool is of friendly usage. A check on the fit convergence is done by genfit2 as well.
The Kalman-Filter-based algorithms have a wide range of applications; among those in particle physics they can perform extrapolations of track parameters
and covariance matrices. The impact of genfit2 on physics simulations performed for the PANDA experiment is shown, with the PandaRoot framework: significant improvement is reported for those channels where a good low momentum tracking is required (pT < 400 MeV/c).

The PANDA experiment in preparation to be setup at FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany will cover many important aspects of hadron physics with cooled anti-proton beams of unprecedented intensity and precision in the momentum range between 1.5 and 15 GeV/c.

The versatile detector is designed to address a rich physics program.
This includes spectroscopy of QCD bound states ranging from charmonium to states composed of light quarks only, which comprises studies of the recently and yet not understood X, Y, and Z states and searches for other exotics. Production of hyperons will shed further light on the
strong interaction in the intermediate region between the perturbative and non-perturbative regime. The time-like nuclear form factors and properties of hadrons in medium will be accessible and round up the experimental program.

In this talk aspects of the PANDA physics program will be highlighted. Major components of the detector are under construction. The current status of the experiment will be presented.

Exclusive binary annihilation reactions induced by antiprotons of momentum from 1.5 to 15 GeV/c can be extensively investigated at FAIR/PANDA [1]. The hadronization process (how a hadron is built from the quantum vacuum created by the pp annihilation and how does it mass, and quantum numbers arise) is the most fundamental problem in QCD. We are specially interested in the channel of charged pion pairs. Whereas this very probable channel constitutes the major background for other processes of interest in the PANDA experiment, it carries unique physical information on the quark content of proton, allowing to test different models (quark counting rules, statistical models,..). However, models as QCD-quark counting rules can not predict absolute cross sections of such exclusive processes. Experimental data are such scarce that no precise and complete angular distributions are available in a large energy range, particularly in the range of PANDA. To study the binary reactions of light meson formation, we are developing an effective Lagrangian model based on Feynman diagrams which takes into account the virtuality of the exchanged particles. Regge factors [2] and form factors are introduced with parameters which may be adjusted on the existing data, which only partially overlap the PANDA energy region. The formalism is built in a suitable way to be easily implemented in an event generator. We will present the first steps of a global analysis of different reactions of antiproton-proton to π0 π0, π+ π− , γγ, ηη, π0 γ, η π0. The final goal is a coherent interpretation of these reactions for reliable predictions of cross sections, energy and angular dependences in the PANDA kinematical range.

This contribution reports about the latest status of the feasibility studies for the measurement of time-like proton electromagnetic form factors (FF's) at the PANDA experiment at FAIR (Germany). Electromagnetic FF's 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, $\mu$, assuming that the interaction takes place through the exchange of a single virtual photon. Due to the low luminosity available at colliders in the past, an individual determination of the time-like electric and magnetic proton FF's was not feasible.
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 both signal reactions $p \bar{p} \rightarrow l^{+} l^{-}$ (l = e, $\mu$) at different antiproton beam momenta. The signal identification and the suppression of the main background process ($p\bar{p} \rightarrow \pi^{+} \pi^{-}$) are studied.
It will be the first time that muon pairs in the final state will be used for the measurement of the time-like electromagnetic 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 time-like electromagnetic FF data from $\bar{p} p \rightarrow e^{+} e^{-}$. For the generation and analysis of the processes of interest, different methods have been used and are compared. The results from the different analyses show that time-like electromagnetic FF's can be measured at PANDA with unprecedented statistical accuracy using both signal channels.