Bulletin of the American Physical Society
2005 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and The Physical Society of Japan
Sunday–Thursday, September 18–22, 2005; Maui, Hawaii
Session JD: Mini-symposium on Chiral and Color Condensation II |
Hide Abstracts |
Sponsoring Units: DNP JPS Chair: Daisuke Jido, Yukawa Institute for Theoretical Physics Room: Ritz-Carlton Hotel Salon 1 |
Thursday, September 22, 2005 9:00AM - 9:30AM |
JD.00001: Strange trybaryon and present experimental program Invited Speaker: Recently, we have performed an experimental search for deeply bound kaonic states by the kaon absorption reaction at rest in a liquid helium target. We observed very distinctive mono-energetic peak formation in a proton missing-mass spectrum. We denote it as a strange tribaryon, S$^0$(3115), with baryon number 3, charge 0, isospin 1 and strangeness -1. If we attribute the mono-energetic peak to the formation of a deeply bound kaonic state, the separation energy of the kaon should be as deep as about 200 MeV. In the present paper, we will overview the present experimental data, and discuss briefly two experimental programs for more detailed information. Work done in collaboration with the KEK PS E471 Collaboration and the KEK PS E549 Collaboration. [Preview Abstract] |
Thursday, September 22, 2005 9:30AM - 9:45AM |
JD.00002: Mass modification of phi meson measured in 12-GeV p+A reaction at KEK-PS E325 Fuminori Sakuma The experiment KEK-PS E325 has measured $e^+e^-$ and $K^+K^-$ pairs produced in 12 GeV p+A reaction, in oder to study the chiral property of dense nucler matter through the analysis of invariant mass spectra. We have already reported modification of $\rho$ and/or $\omega$ mesons in PRL.86,5019(2001) and nucl-ex/0504016. In this talk, we will present our new results which show the modification of $\phi$ meson at normal nuclear density. Discussions will be made based on the observations both in $e^+e^-$ and $K^+K^-$ invariant mass spectra. [Preview Abstract] |
Thursday, September 22, 2005 9:45AM - 10:00AM |
JD.00003: Future step of pionic atom spectroscopy Kenta Itahashi High precision spectroscopy of pionic atoms has been yielding precious information on in-medium property of pion and also on the nuclei that are treated as high energy density matter. One of the most remarkable results obtained is quantitative measurement of the chiral order parameter inside the nucleus. However, its deduction still holds large ambiguities. I will briefly introduce the present status of the pionic atom spectroscopy and then proceed to possible future experimental plans in GSI, Germany and in RIKEN, Japan. [Preview Abstract] |
Thursday, September 22, 2005 10:00AM - 10:15AM |
JD.00004: Structure and Formation of Mesic Atoms and Mesic Nuclei Satoru Hirenzaki The light pseudoscalar mesons are interpreted as the Nambu-Goldstone bosons and their properties, especially meson mass spectra, are explained as the consequences of the symmetry breaking pattern of QCD in vacuum. Thus, it seems very interesting to study the meson properties in nucleus to obtain new information on chiral dynamics at finite density, especially the partial restoration of chiral symmetry around normal nuclear density. In this context, meson-nucleus bound systems (mesic atoms and mesic nuclei) are one of the most interesting systems. We study the structure and formation of these systems and discuss the experimental feasibilities. [Preview Abstract] |
Thursday, September 22, 2005 10:15AM - 10:30AM |
JD.00005: Self-bound state with kaon condensates and its implications for deeply-bound kaonic nuclei Takumi Muto We study the equation of state with kaon condensates in hyperonic matter, where hyperons ($\Lambda$) are mixed in the ground state of neutron-star matter, by the use of the effective chiral Lagrangian for the kaon-baryon interaction, combined with the nonrelativistic baryon-baryon interaction model. Due to much softening of the EOS caused by both hyperon-mixing and kaon condensates, it is shown that the energy of the system has a local minimum as a density isomer, which leads to a metastable configuration of a self-bound kaon-condensed star in addition to a usual kaon-condensed star with a two-phase structure obtained by the Maxwell's construction. Based on the EOS, a possible existence of a kaon-condensed nucleus and its relation to deeply bound kaonic nuclei are also considered in a simple liquid-drop picture. [Preview Abstract] |
Thursday, September 22, 2005 10:30AM - 10:45AM |
JD.00006: Dense-matter and hypernuclear systems with an SU(3) chiral symmetric relativistic mean field model Kohsuke Tsubakihara, Akira Ohnishi Hyperons are believed to play important roles in dense matter such as neutron star and supernovae. In studying hyperonic dense matter, we should invoke accumulated knowledges on hypernuclei. Relativistic Mean Field (RMF) models is one of the way to understand dense matter and hypernuclei consistently. In this model, it is possible to introduce symmetries directly. In order to reduce ambiguities further, we introduce chiral symmetry in RMF. However, we haven't succeeded in constructing satisfactory RMF Langrangian with chiral symmetry. For example, privious models have some shortcomings such as chiral symmetry restoration below normal nuclear density, too stiff EOS and so on. Last time, we have introduced SU(2) chiral symmetry to scaler meson self-interaction in RMF Lagrangian with the result of strong coupling limit lattice QCD as $U^{SU(2)}_\sigma = a\log\sigma^2 + b\sigma^2 + c_\sigma\sigma$, and shown that it works very well. EOS becomes softer than privious RMF models with chiral symmetry. We can also well explain the binding energies of normal nuclei and single $\Lambda$ hypernuclei. Now, it is desireble to extend our model to that having SU(3) chiral symmetry. This extention enables us to get information of hyperons in hyperonic dense matter and hypernuclei from the bond energy of $\Lambda\Lambda$ in finite nueclei, $\Delta$B${}_{\Lambda\Lambda}$ of ${}^{6}_{\Lambda\Lambda}$He. In this time, we'll report our recent results about single and double $\Lambda$ hypernuclei and hyperonic dense matter. [Preview Abstract] |
Thursday, September 22, 2005 10:45AM - 11:00AM |
JD.00007: Systematic study of dense $\bar{K}$ nuclei with a revised $\bar{K}N$ potential Akinobu Dote, Yoshinori Akaishi, Toshimitsu Yamazaki Due to the strongly attractive $\bar{K}N$ interaction, a $K^-$ meson can be deeply bound in nuclei. So far, we have investigated $\bar{K}$ nuclei with a phenomenological $\bar{K}N$ interaction. According to my study with the method of antisymmetrized molecular dynamics, we have found that a $K^-$ meson can be bound by about 100 MeV below nucleus-K threshold in various light nuclei and makes nuclei drastically shrunk. $\bar{K}$ nuclei are very dense (over 4 times normal density) and have so interesting structures that we have never seen in usual nuclei. Recently, a few experimental groups have discovered $\bar{K}$ nuclei; $ppnK^-$ and $pnnK^-$ by Iwasaki $et$ $al$ and $ppK^-$ by Nagae $et$ $al$. According to these results, $\bar{K}$ nuclei are more deeply bound than our prediction. Taking them into account, $\bar{K}N$ potential should be somewhat enhanced than original one in case of my calculation. In addition, Nucleon-Nucleon $LS$ interaction is found to give large contribution by the study of $pnnK^-$ which seems to have $(0s)^2(0p)$ nucleon configuration. Taking these points into consideration, we have confirmed that binding energies of various $\bar{K}$ nuclei increase to about 200 MeV measured from nucleus-K threshold. We expect that their structures should change more drastically. Moreover, we have interests in double $\bar{K}$ nuclei, which have two $K^-$ mesons. They are expected to be so deeply bound. I will report on these issues. If possible, I'd like to mention other types of interaction and analysis from the viewpoint of quarks. [Preview Abstract] |
Thursday, September 22, 2005 11:00AM - 11:15AM |
JD.00008: Formation of Kaonic Atoms and Kaonic Nuclei by In-flight ($K^-,p$) reactions Junko Yamagata, Hideko Nagahiro, Satoru Hirenzaki We study the kaonic atom and kaonic nucleus formation by the in-flight ($K^-, p$) reactions for C, O, Si and Ca target cases theoretically. Deeply bound kaonic atoms were predicted to exist as quasi-stable states and were expected to be observed in some proper experimental methods. Kaonic nuclear states are also expected to exist with large decay widths. We evaluate the formation cross sections of the kaonic atoms and kaonic nuclei using the Green function method with the appropriate energy dependent optical potentials. We will discuss the possibilities to observe the kaonic states in the ($K^-, p$) reactions based on the realistic theoretical calculations. [Preview Abstract] |
Thursday, September 22, 2005 11:15AM - 11:30AM |
JD.00009: Search for $\overline{K}NN$ bound states with the FINUDA spectrometer Hiroyuki Fujioka The existence of a deeply-bound kaonic state, which includes an antikaon inside the nucleus, is theoretically predicted by Akaishi and Yamazaki, according to their $\overline{K}N$ potential. In their model, the $\Lambda$(1405) is regarded as a $\overline{K}N$ bound state. We have searched for the lightest kaon-bound system ($\overline{K}NN$) with the FINUDA spectrometer, which is installed at the $e^+e^-$ collider DA$\Phi$NE. The $\phi$-meson, abundantly produced by DA$\Phi$NE, decays into $K^+K^-$, with the kinetic energy of $K^\pm$ $\sim 16\,\mathrm{MeV}$. This slow $K^-$ stops inside a very thin nucleus target and interacts with a nucleus. We installed five kinds of targets ($^6$Li, $^7$Li, $^{12}$C, $^{27}$Al and $^{51}$V) surrounding the beam pipe in the first run (2003--2004). In this talk, I will discuss non-mesonic decay modes of a $\overline{K}NN$ bound system, clearly observed in the back-to-back angular correlation between a hyperon and a nucleon emitted from the $K^-$ reaction vertex. [Preview Abstract] |
Thursday, September 22, 2005 11:30AM - 11:45AM |
JD.00010: Search for Kaonic Nuclear Clusters in Nuclear Collisions with FOPI Ken Suzuki, Laura Fabbietti, Michael Cargnelli, Paul Kienle, Johann Marton, Johann Zmeskal, Norbert Herrmann, Toshimitsu Yamazaki Recently, exotic nuclear systems involving a $\bar{K}$, ($K^-$ or $\bar{K}^0$) as constituent (such as $ppK^-$, $ppnK^-$, $pppK^- $, $pppnK^-$ and $ppnnK^-$) were predicted by Akaishi and Yamazaki to have narrow discrete bound states with large biding energies as much as 100 MeV due to the strong $K^{-}-p$ attraction, which may lead the system to have a much higer density than normal nuclear density. We produce and identify such $\bar{K}$ clusters in heavy-ion collision or proton induced reactions by making use of the capability of the FOPI detector at GSI which is enable to reconst invariant-mass from all the charged trajectories of the decay particles of K clusters such as $ppK\rightarrow \Lambda +p$, $ppnK\rightarrow \Lambda+d$ and $pppK\rightarrow \Lambda+p+p$. $ppK^-$ is produced with proton induced reaction on $d$ target as $p+d \rightarrow [\Lambda(1405)+p] + K^0 + p \rightarrow ppK^- + K^0 + p$, where $\Lambda(1405) \equiv pK^- / n\bar{K}^0$ works as a doorway to form $\bar{K}$ cluster. We can identify the $ppK^-$ in the missing mass spectrum, and simultaneously study its decay pattern by invariant mass method. With light nuclear target more heavier $\bar{K}$ clusters can be produced by $\Lambda(1405)$ production and successive $\bar{K}$ transfer / knock-on reactions. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700