No Arabic abstract
We show that the D^- meson will form narrow bound states with ^{208}Pb. Mean field potentials for the D^0, D^0-bar and D^- in ^{208}Pb are calculated self-consistently using the quark-meson coupling (QMC) model in local density approximation. The meson-^{208}Pb bound state energies are then calculated by solving the Klein-Gordon equation with these potentials. The experimental confirmation and comparison with the D^0-bar and D^0 will provide distinctive information on the nature of the interaction between the charmed meson and matter.
We calculate theoretically the formation spectra of eta(958)-nucleus systems in the (p,d) reaction for the investigation of the in-medium modification of the eta mass. We show the comprehensive numerical calculations based on a simple form of the eta optical potential in nuclei with various potential depths. We conclude that one finds an evidence of possible attractive interaction between eta and nucleus as peak structure appearing around the eta threshold in light nuclei such as 11C when the attractive potential is stronger than 100 MeV and the absorption width is of order of 40 MeV or less. Spectroscopy of the (p,d) reaction is expected to be performed experimentally at existing facilities, such as GSI. We also estimate the contributions from the omega and phi mesons, which have masses close to the eta meson, concluding that the observation of the peak structure of the eta-mesic nuclei is not disturbed although their contributions may not be small.
The real and imaginary parts of the bar K^0 d scattering length are extracted from the bar K^0 d mass spectrum obtained from the reaction pp to d bar K^0 K^+ measured recently at the Cooler Synchrotron COSY at Julich. We extract a new limit on the K^- d scattering length, namely Im a le 1.3 fm and |Re a| le 1.3 fm. The limit for the imaginary part of the K^- d scattering length is supported by data on the total K^- d cross sections.
We are going to perform an inclusive spectroscopy experiment of eta mesic nuclei with the 12C(p,d) reaction to study in-medium properties of the eta meson. In nuclear medium, the eta meson mass may be reduced due to partial restoration of chiral symmetry. In case of sufficiently large mass reduction and small absorption width of eta at normal nuclear density, peak structures of eta mesic states in 11C will be observed near the eta emission threshold even in an inclusive spectrum. The experiment will be carried out at GSI with proton beam supplied by SIS using FRS as a spectrometer. The detail of the experiment is described.
We argue that the reaction mechanism for the coherent pion production is not known with sufficient accuracy to determine the neutron radius of 208Pb to the claimed precision of 0.03 fm.
We evaluate the s-wave interaction of pseudoscalar and vector mesons with both charm and beauty to investigate the possible existence of molecular $BD$, $B^*D$, $BD^*$, $B^*D^*$, $Bbar D$, $B^*bar D$, $Bbar D^*$ or $B^* bar D^*$ meson states. The scattering amplitude is obtained implementing unitarity starting from a tree level potential accounting for the dominant vector meson exchange. The diagrams are evaluated using suitable extensions to the heavy flavor sector of the hidden gauge symmetry Lagrangians involving vector and pseudoscalar mesons{, respecting heavy quark spin symmetry}. We obtain bound states at energies above 7 GeV for $BD$ ($J^P=0^+$), $B^*D$ ($1^+$), $BD^*$ ($1^+$) and $B^*D^*$ ($0^+$, $1^+$, $2^+$), all in isospin 0. For $Bbar D$ ($0^+$), $B^*bar D$ ($1^+$), $Bbar D^*$ ($1^+$) and $B^*bar D^*$ ($0^+$, $1^+$, $2^+$) we also find similar bound states in $I=0$, but much less bound, which would correspond to exotic meson states with $bar b$ and $bar c$ quarks, and for the $I=1$ we find a repulsive interaction. We also evaluate the scattering lengths in all cases, which can be tested in current investigations of lattice QCD.