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The Density-dependent Correlations among Observables in Nuclear Matter and Hyperon-rich Neutron Stars update: 2009-07-14 (Tue) Date: 2009/7/10(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Schun Uechi (RCNP)
Title: The Density-dependent Correlations among Observables in Nuclear Matter and Hyperon-rich Neutron Stars
Abstract: The conserving $\sigma$-$\omega$-$\rho$ mean-field approximation with nonlinear interactions of hadrons has been applied to examine properties of nuclear matter and hyperonic neutron stars. The nonlinear interactions that will produce density-dependent effective masses and coupling constants of hadrons are included in order to examine density-correlations among properties of nuclear matter and neutron stars such as binding energy, incompressibility, $K$, symmetry energy, $a_4$, and hyperon-onset density, maximum masses of neutron stars. The conditions of conserving approximations in order to maintain thermodynamic consistency to an approximation are essential for the analysis of density-dependent correlations.
Reference: Advances in High Energy Physics Volume 2009 (2009), Article ID 640919, 15 pages
■ Hidden gauge formalism for the radiative decays of axial-vector mesons update: 2009-06-23 (Tue) Date: 2009/6/25(Thur.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Prof. Hideko Nagahiro (Nara Women's Univ.)
Title: Hidden gauge formalism for the radiative decays of axial-vector mesons
Abstract : We study the radiative decay of the axial-vector meson which is introduced as a dynamically generated resonance by pseudo-scalor and vector meson scattering. We use the vector meson Lagrangian obtained from the hidden gauge symmetry (HGS) formalism which is well suited to study this problem since it deals with pseudoscalar and vector mesons in a unified way.
We show explicitly the gauge invariance of the set of diagrams that appear in the approach and evaluate the radiative decay width of the a1(1260) and b1(1235) axial-vector meson resonances into pi gamma. We also include the contribution of loops involving anomalous couplings and compare the results to those obtained previously within another formalism.
[Reference] H. Nagahiro L. Roca A. Hosaka and E. Oset, Phys.Rev.D79, 014015 (2009)
■ He4+He4 system as a gateway to alpha cluster structure and He4+n system as a gateway to nuclear shell structure update: 2009-06-23 (Tue) Date: 2009/5/29(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Prof. Hiroshi Toki (RCNP)
Title: He4+He4 system as a gateway to alpha cluster structure and He4+n system as a gateway to nuclear shell structure
Abstract: We are now able to handle tensor interaction in shell model framework. We shall first discuss the essence of treating tensor interaction. We then show how to include the tensor interaction in many body system using the essence of the tensor interaction. We apply this method to alpha plus alpha system and also alpha plus one nucleon system. We show a numerical method of calculating these systems explicitly using correlated gaussian method. ■ Beyond mean field approximation in nuclear matter update: 2009-05-18 (Mon) Date: 2009/5/15(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Jinniu Hu (RCNP)
Title: Beyond mean field approximation in nuclear matter
Abstract: As we known, the relativistic mean field (RMF) theory is very successful to description of infinite nuclear matter and finite nuclei system. However, the pion as the most important meson in strong interaction has zero contribution with the Hartree approach. Furthermore, some realistic physics effects are included in the phenomenological parameters in the RMF model such as the nucleonic response to the scalar field, the finite size of nuclei and the powerful short range repulsive in the nucleon-nucleon interaction.
Therefore, in this talk, I will give some tests to study the infinite nuclear matter beyond the mean field theory. The first test is introducing the nonlinear sigma term in the effective mass. It denotes the nucleon response to the sigma field which has appeared in the quark-meson coupling (QMC) model. With this term we can largely reduce the incompressibility K of the extended chiral sigma (ESC) model to make it consistent with the experiment data very well.
We also study the pion effect in the nuclear with the ESC model by using the tensor optimized shell-model (TOSM) prescription. Two particle-Two hole states are included in the variational nucleon wave function. The corresponding thing is that we also consider the fluctuation of mesons for meson field approximation. The Fock contribution of various mesons is obtained. With these Fock terms, we can study the finite size effect of nuclei and the short range correlation in the nucleon-nucleon interaction.
■ Baryons in holographic QCD with curved extra-dimension update: 2009-05-18 (Mon) Date: 2009/5/8(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Kanabu Nawa (RCNP)
Title: Baryons in holographic QCD with curved extra-dimension
Abstract: We study baryons[1] and baryonic matter[2] in holographic QCD with D4/D8/D8-bar multi-D brane system in type IIA superstring theory.
Holography is a new concept of superstring theory as the duality between gauge theory and supergravity through D-branes. An essential property of holography is the strong-weak duality (S-duality) between gauge theory and supergravity; coupling strengths are transversely related with each other. Therefore, if QCD can be constructed on the surface of D-branes, its non-perturbative aspects can be analyzed by the tree-level dual supergravity calculation, which is called the holographic QCD.
In our study, we introduce chiral soliton (Skyrmion) picture to discuss baryons in holographic QCD. We also analyze the baryonic matter in holographic QCD by placing the single Skyrmion on a three-dimensional closed manifold S^3. We propose new striking pictures for the baryonic matter as 'pion dominance' and 'swelling of baryons', which correspond to a precursory phenomena of deconfinement in dense baryonic matter.
We also compare the Skyrmions in holographic QCD with those in hidden-local symmetry approach. Then we show that the roles of vector mesons for the baryon can be largely changed due to the curved extra-dimension[3].
[1]K. Nawa, H. Suganuma and T. Kojo, Phys. Rev. D75, 086003 (2007) [hep-th/0612187]. [2]K. Nawa, H. Suganuma and T. Kojo, Phys. Rev. D79, 026005 (2009) [arXiv:0810.1005[hep-th]]. [3]K. Nawa, A. Hosaka, H. Suganuma, arXiv:0901.3080[hep-th]. ■ phi-meson photo production with coupled channel approach update: 2009-05-18 (Mon) Date: 2009/4/17(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Sho Ozaki (RCNP)
Title : phi-meson photo production with coupled channel approach
Abstract： Recently, several photon facilities have been reporting interesting results in the energy region of the strangeness (s\bar{s}) production, including the pentaquarks, \Lambda resonances and \phi-meson. Among those, \phi-photoproduction has a unique feature such that the gluon dynamics (Pomeron contribution) dominates because the OZI rule suppress hadron dynamics due to the s\bar{s} dominance of \phi-meson. Previously, Pomeron and meson exchange model successfully reproduced differential cross sections and spin observables in the forward angle region. In 2005, LEPS group, however, has observed a peak structure near the threshold. It is known that such a structure is difficult to be explained within this model. In order to reproduce the structure we investigate coupled channel effects in the \phi-meson photoprduction. Especially we pay attention to the following two aspects. One is an on-shell kaon exchange effect in the transition amplitude \phi N\to K \Lambda(1520), which is kinematically allowed, in the energy region where a peak structure has been observed in \phi-photoproduciton. We also discuss the possibility of a nucleon resonance which may contain large s\bars components. In this seminar I discuss results of these effects. ■ Nuclear breakup reaction studied by the continuum-discretized coupled-channel method with the complex scaling method update: 2009-05-18 (Mon) Date: 2009/4/10(Fri.) 14:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Masaaki Takashina (RCNP)
Title : Nuclear breakup reaction studied by the continuum-discretized coupled-channel method with the complex scaling method
Abstract : In the weakly bound nuclei (such as d, 11Be, 6He, 11Li etc.) induced reactions, the breakup process is important. However, its treatment is very difficult because one should solve three- or four-body scattering state including the target nucleus. Therefore, it is a challenging subject in the nuclear reaction theory how to describe the nuclear breakup reactions.
The continuum-discretized coupled-channel (CDCC) method is known to be one of the powerful method to describe the breakup reactions [1], and has been applied for a number of the breakup reactions. Recently, the pseudo-state (PS) CDCC has been developed [2], which enables us to obtain the S matrix element as the function of the continuous momentum (k) from the discretized S matrix element using the smoothing function for the two-body breakup case. However, for the three-body breakup case, it is difficult to evaluate the smoothing function.
In order to overcome this difficulty, we consider applying the complex scaling method to CDCC. The complex-scaled CDCC (CS-CDCC) is expected to give us the continuum S matrix element without the smoothing function due to the successful results of the previous study for the Coulomb breakup reaction in the external field model [3].
In this talk, we briefly introduce the CDCC method and the complex-scaling method. Then, we report the present results of the CS-CDCC method.
[1] M. Kamimura et al., Prog. Theor. Phys. Suppl. 89, 1 (1986). [2] T. Matsumoto et al., Phys. Rev. C 68, 064607 (2003). [3] T. Myo et al., Phys. Rev. C 63, 054313 (2001). ■ The role of pions on nuclei with extended chiral Hartree model update: 2008-11-19 (Wed) Date: 2008/11/20(Thurs.) 15:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Yoko Ogawa (RCNP)
Title : The role of pions on nuclei with extended chiral Hartree model
Abstract: The formalism of an extended chiral Hartree model is presented. This is a method for proper treatment of a pion-exchange interaction in the nuclear many-body problem. The dominant term of the pionic correlation is expressed in 2p-2h states with particle-holes having the quantum number not only the J$^{\pi} = 0$^{-}$ ( spherical ansatz), but also with higher spin quantum numbers, J$^{\pi} = 1^{+}, 2^{-}, 3^{+}$, ... to describe the full strength of the pionic correlation in the intermediate- and long-range region ( r > 0.5 fm ). We furthre inculde the effect of the short-range repulsion. We apply this model to $^{4}$He nucleus as a pilot calculation. We report numerical reults and the role of pions on nuclei.
■ SU2_c NJL model and its hadronization in the path integral formalism update: 2008-11-19 (Wed) Date: 2008/11/6(Thurs.) 15:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Prof. Hiroshi Toki (RCNP)
Title : SU2_c NJL model and its hadronization in the path integral formalism
Abstract: We discuss the hadronization of NJL model lagrangian and derive the Gellmann-Levy lagrangian using the path integral method. We work out the property of quark-hadronic matter at finite temperature and density, where the confinement property of quarks is formulated in terms of the Polyakov line potential as a projection to color singlet states. We work out explicitly the case of color SU2. ■ Kaon and Phi meson photoproduction update: 2008-10-27 (Mon) Date: 2008/10/23(Thurs.) 15:00-
Place: RCNP Lecture Room, 4th floor
Speaker: Dr. Sho Ozaki (RCNP)
Title : Kaon and Phi meson photoproduction
Abstract: I discuss kaon and phi meson photoproduction from the nucleon. For kaon photoproduction, we found that the QCD anomaly plays a very important role in the spin observable. The anomalous effect renormalize to K* exchange amplitudes. This fact explains the phenomenologically determined large K* couplings used in the previous studies of the kaon photoproduction. Next, I discuss phi photoproduction. Recently, LEPS group has reported a small bump structure in the differential cross section near the threshold region. To explain the bump structure, we attempt to introduce a new reaction mechanism using coupled channel K-matrix approach and discuss the role of this mechanism in phi photoproduction. ■ Vector-axialvector mixing from a chiral effective field theory at finite temperature) update: 2008-07-29 (Tue) Date : 2008/8/1 (Fri) 14:00 -
Place : RCNP 4F Lecture Room
Speaker : Dr. Chiriro Sasaki (TU Muenchen)
Title :Vector-axialvector mixing from a chiral effective field theory at finite temperature)
Abstract : In the presence of hot matter the vector and axialvector current correlators are mixed due to pions in the heat bath. At low temperatures this process is described in a model-independent way in terms of a low-energy theorem based on chiral symmetry and consequently the vector spectral function is modified by axialvector mesons through the mixing theorem. The validity of the theorem is, however, limited to temperatures $T << 2f_\pi$, where $f_\pi$ is the pion decay constant in vacuum. At higher temperatures one needs in-medium correlators systematically involving hadronic excitations other than pions. In this talk, we present a systematic study of the mixing (V-A mixing)in the current correlation functions and its evolution with temperature within an effective field theory. In the chiral limit the axialvector meson contributes significantly to the vector spectral function; the presence of the $a_1$ reduces the vector spectrum around the $ \rho$ meson mass $M_\rho$ and enhances it around the $a_1$ meson mass $M_{a1} $. For physical pion mass $m_\pi$, the $a_1$ contribution above $M_ {a1}$ still survives although its strength is somewhat reduced. The a1-rho-pi coupling vanishes at the criticaltemperature $T_c$ and thus the V-A mixing also vanishes. A remarkable observation is that even for finite $m_\pi$ the $\rho$ and $a_1$ meson masses are almost degenerate at $T_c $. The vanishing V-A mixing at $T_c$ stays approximately intact.We also discuss the influence of explicit $\bar{q}q$ scalar modes on the current correlators.
■ Internal One-Particle Density Matrix for > Bose-Einste in update: 2008-07-29 (Tue) Date: July 24 (Thur.) 13:30-
Place: Lecture room, 4th floor
Speaker: Prof. Hisashi Horiuchi (RCNP)
Title: Internal One-Particle Density Matrix for > Bose-Einste in Condensates with Finite Number of Particles in a Harmonic Potential Field
Abstract: For the sake of clarification of the structure of the Hoyle state in 12C, we perform, as a general problem, investigations on the internal one-particle density matrix in the case of Bose-Einstein condensates with a finite number of particles in a harmonic potential field. We solve the eigenvalue problem of the Pethick-Pitaevskii-type internal density matrix and find a fragmented condensate. Since the Jacobi-type internal density matrix gives complete condensation into one state, the internal one-particle density matrix is different in general for different choices of the internal coordinate system. We propose two criteria for the choice of the adequate coordinate systems which give us a unique answer for the internal one-particle density matrix.
2006
・12/22 K. Yoshihara Abstract File (pdf) NJLクォーク模型によるmeson崩壊幅の計算
・12/15 S. Chatani Abstract 二重魔法数周辺の原子核に対するロー中間子のテンソル結合項の影響
・12/1 S. Ozaki Abstract File (pdf) Reaction Mechanism For Kaon and Hyperon Photoproductions
・11/10 Y. Manabe Abstract File (pdf) The effect of the negative energy component of the two nucleon system
・10/27 T. Saito Abstract 閉じ込め相および非閉じ込め相におけるクォーク伝播関数
・10/20 T. Myo Abstract File (pdf) Structures of 11Li with tensor and pairing correlations
・7/21 K. Nagata Abstract File (pdf) Chiral symmetry of the nucleon, delta and Roper resonance
・7/7 K. Yoshihara Abstract File (pdf) particle decay in quark model with NJL interaction
・6/30 Y. Nakagawa Abstract File (pdf) Confinement mechanism in Coulomb gauge QCD -- Infrared divergence of the color-Coulomb self-energy
・6/23 A. Hosaka Abstract File (pdf) Paper by W. Pauli and S.M. Dankoff "The pseudoscalar meson field with strong coupling" PR 62,85 (1942)
・6/16 Y. Ogawa Abstract File (pdf) Charge and parity projected mean field model with pion for finite nuclei
・6/9 M. Yamaguchi Abstract File (pdf) Faddeev three-cluster calculations of the helium isotopes
・6/2 H. X. Chen Abstract File (pdf) Exotic tetraquark ud anti-s anti-s of jp=0+ in the QCD sum rule
・5/26 T. Endo Abstract Finite-size effects on the hadron-quark mixed phase in hybrid stars
・5/12 A. Haga Abstract File (pdf) Relativistic nuclear model including the vacuum polarization
・4/20 J. Yamagata Abstract File (pdf) Indications of Kaon bound states in In-flight({\bar K},N) spectra
・4/13 S. Chatani Abstract File (pdf) New parameter search for the relativistic mean field (RMF) model
・3/3 B. Yilmaz Abstract File (pdf) Stochastic fusion dymanics of heavy ions
・1/30 T. Endo Abstract ハドロン・クォーク混合相における有限サイズ効果
・1/12 T. Nakamura 重陽子におけるペンタクォーク光生成反応
・1/23 Y. Nakagawa Abstract CoulombゲージQCDでの閉じ込め機構の研究
2005
・4/15 T. Saito Abstract, File (pdf) QCD color confinement in Coulomb gauge and color interactions between two quarks
・4/22 H. Nagahiro Abstract, File (pdf) $\eta$-mesic nuclei and baryon chiral symmetry in medium
・6/3 S. Nakamura Abstract, File (pdf) 原子核における有効相互作用
・6/10 S. Tamenaga Abstract, File (pdf) The effect of tensor coupling in the chiral sigma model
・6/17 L.S. Geng Abstract, File (pdf) Ground state properties of finite nuclei in the relativistic mean field model
・6/24 Y. Nakagawa Abstract, File (ppt) Confinement mechanism in Coulomb gauge QCD
・7/1 Y. Akasaka Abstract 高エネルギー領域におけるRegge現象
・7/8 K. Nagata Abstract The two nucleon states in a chiral quark-diquark model
・7/15 S.I. Nam Abstract Effective Lagrangian Approach for the Production of Pentaquark Baryons
・7/22 A. Deuzeman Coulomb gauge QCD: finite temperature and renormalization scale effects
・10/7 T. Ohsaku Abstract Dynamical Chiral Symmetry Breaking and Superconductivity in the Supersymmetric Nambu$-$Jona-Lasinio Model at finite Temperature and Density
・10/14 K.S. Choi Abstract gamma N -> eta N reaction for the study of a new N*(1675) resonance
・10/21 T. Saito Abstract Lattice Calculation of Gluon Screening Masses
・11/4 T. Myo Abstract, File (pdf) Tensor-correlated shell and cluster models and their applications to He isotopes
・11/10 T. Kojo Abstract Search for pentaquark states with valid Borel analysis
・11/25 T. Saito Abstract Scaling of Coulomb string tension
・12/9 Y. Manabe Abstract The effect of the negative component of two nucleon system.
・12/16 S. Tamenaga Abstract One-loop corrections as origin of spontaneously chiral symmetry breaking in the massless chiral sigma model
2004
・4/8 A. Hosaka File (pdf) Theta in a quark model
・4/15 S. Nakamura Abstract, File (pdf) How to integrate out heavy degrees of freedom in effective field theory
・ 4/22 T. Myo Abstract, File (pdf) Tensor correlation in neutron halo nuclei
・ 5/6 K. Tsuji Abstract, File (pdf) ニュートリノ･気モーメントとニュートリノ─重陽q反応
・5/20 S. Nakamura Abstract, File (pdf) Unitary Correlation Operator Method
・5/27 K. Nagata Abstract, File (pdf) The properties of nucleons in a chira quark-diquark model
・6/10 T. Hyodo Abstract, File (pdf) (mov) ペンタクォーク研究の最近の動向
・6/17 A. Haga Abstract, File (pdf) Nonspectral RPA for finite nuclei
・6/29 S. Tamenaga Abstract, File (pdf) Chiral sigma model and Vacuum polarization
・7/1 Y. Ohnishi Abstract, File (pdf) Chiral-odd twist-3 distribution function e(x) of the nucleon
・9/9 S.-I. Nam Abstract, File (pdf) Kaon light cone wave function from the QCD instanton vacuum
・9/16 Y. Manabe Abstract Separable and one-boson exchange kernel of interaction
・10/7 A. Hosaka Abstract Decay of Theta+ in a quark model
・10/14 L.S. Geng Abstract Do we need more terms in the RMF theory?
・10/21 Y. Ogawa Abstract, File (pdf) Chiral Symmetry and Finite Pion Mean Field in Nuclei
・11/18 T. Hyodo Abstract, File (pdf) (mov) Two-meson cloud contribution to the baryon antidecuplet binding
・11/26 W. Sakai Abstract Generalized Jastrow factor applied to cluster calculation of cluster model for light nuclei
・12/1 N. Nose-Togawa Abstract 半無限系核物質における相対論的平均場理論
・12/9 S. Yasui Abstract Chiral symmetry breaking and stability of strangelets --recent results and future plan --
・12/16 Y. Nakagawa Abstract, File (pdf) A Review of The Dual Ginzburg-Landau Theory 2003
・ 5/8 A. Hosaka Z+baryon
・ 5/15 T. Hyodo Scattering amplitude
・ 5/22 Y. Manabe Relativistic BS equation
・ 5/29 N. Hamamoto Relativistic deuteron
・ 6/12 T. Myo Properties of Resonant and Continuum States based on the complex scaling method [pdf] [scan]
・ 10/10 K. NagataStructure of the nuclear force in the chiral quark-diquark model
