Charm production in antiproton interactions on nucleons and nuclei

Abstract

The general area of this project is the hadron physics, which is closely connected with the physics program of the PANDA experiment at the upcoming Facility for Antiproton and Ion Research (FAIR) in Heavy ion Research Lab (GSI) at Darmstadt, Germany. PANDA will study interactions between antiprotons (p-bar) and fixed target protons (p) and nuclei (A) in the momentum range of 1.5 - 15 GeV/c. These studies are intended to address fundamental questions of QCD that lie mostly in the non-perturbative regime. Some of them are: (i) Hadron spectroscopy up to the region of charm quark. The focus of interest here is to search for exotic states like glue balls, hybrids and multiquark states in the light quark domain and in the hidden and open charm region. (ii) Study of properties of hadrons (particularly in the charm sector) in the nuclear matter. (iii) Antiproton induced reactions are a very effective tool to implant strange and charmed baryons in nuclei. PANDA will particularly study charmed hypernuclei which are of great importance for under standing the Charm baryon-nucleon interaction. Similarly it will study double ›hypernuclei that provide information about ›› interaction. The latter is important for understanding the composition of the neutron star core. The experimental studies at PANDA will profit from the high yields of antiproton induced reactions and from the fact that all quantum number combinations for directly formed states are allowed, which in contrast to e e+ reactions that allow direct population of only those states having the quantum numbers of photon. It is therefore, extremely important and timely to investigate the production of charmed baryons (›+_c) interactions at beam momenta of and mesons (D and D*) production in pinterest to the PANDA experiment. The information and experience gained from these studies will in turn be useful in the calculations of production of ›_c hypernuclei and D-mesic nuclei in p-bar A interactions. This will also enable to study the modifications in the properties of charmed mesons and baryons in the nuclear matter. The visiting researcher, Prof Radhey Shyam of Saha Institute of Nuclear Physics(Kolkata, India), in collaboration with Prof. Kazuo Tsushima (the host), have done considerable amount of work on the production of › and ž hypernuclei in photon, proton and K induced reactions on nuclei. We have developed a covariant effective Lagrangian model where full field theoretic structure of the interaction vertices are retained and baryons are treated as Dirac particles. We intend to extend this model to the charmed sector. Collaboration with Prof. R. Shyam who is quite experienced and is a known expert of this field, will be vital for the successful execution and completion of this project. This will put the UNICSUL, Sao Paulo state and Brazil in the forefront of research in this important area. This research project will be developed and carried out mainly in LFTC – Laborato de Física Teórica e Computacional, Cruzeiro do Sul University, Sao Paulo. Therefore, it will require the visit by Prof. R. Shyam to this institution. The local master and Ph.D students as well as postdocs., will benefit by interactions with Prof. R. Shyam. (AU)