The PANDA experiment : physics goals and experimental setup

PANDA (antiProton ANnihilation at DArmstadt) is an experiment that will run at the GSI laboratory, Darmstadt, Germany, in 2018. A high intensity antiproton beam with momentum up to 15 GeV/c will collide on a xed proton target (pellet target or jet target). A wide range of physics topics will be investigated : charmonium states and open charm states above theDD threshold; exotic states like glueballs, oddballs, hybrids, multiquarks, molecules; the spectroscopy of the excited states of strange and charm baryons; nonperturbative QCD dynamics in the pp production cross section of charm and strange baryons and their spin correlations; the behaviour of hadrons in nuclear matter; hypernuclear physics; electromagnetic proton form factors in the timelike region; the CP violation in the charm sector, rare and forbidden decays of charm baryons and mesons. PANDA is an experiment that will run at the GSI laboratory in Darmstadt (Frankfurt, Germany) around 2010. It will continue and extend the successful physic program started at Cern with LEAR and Fermilab with E760/E835. Presently the PANDA collaboration is composed by a group of 420 physicists from 53 institutions of 16 countries. The experiment will use a very high intensity antiproton beam with momentum ranging from 1.5 GeV/c to 15 GeV/c, on a xed proton target (pellet target or jet target). The range of energy in the center of mass covered goes from √ s = 2.25 up to √ s = 5.47 enabling the study a wide physics topic range, some of them described in the following sections. The p beam will be accumulated in the HESR storage ring in two modes : a high intensity mode, with a beam current of ∼ 2× 10 p/sec and stochastic cooling leading to a luminosity of 2× 10 cms and δp/p = 10, and a high resolution mode with electron cooling, a luminosity of 2× 10 cms and δp/p = 10. 1 Some of the Panda Physics goals For lack of space it is impossible here to describe all physics measurements feasible in PANDA. Only a few are briey described in the following. For a more detailed description see the PANDA Physics Book [1]. 1.1 Charmonium physics The pp system can form (non-exotic) states with any J not just 1−− as in the ee experiments. Consequently all the charmonium states predicted by the potential models, can be studied in PANDA. The mass and width resolution of the states formed is driven essentially by the resolution of the p momentum and less by the detector performances, as demonstrated by the experience of the experiment E835 at Fermilab. with 2 × 10 cms luminosity PANDA will accumulate 8pb integrated luminosity per day (assuming overall 50% efciency) and 10 ÷ 10 cc states/day. In 6 months data taking 1.5fb will be accumulated, approximately 10 times better than the Fermilab experiments E760/E835 with a better detector, with better angular coverage, with magnetic eld and the ability of detecting hadronic decay modes. On leave from Dipartimento di Fisica, Pavia University