Date: Thu, 30 Sep 10 00:06:51 GMT Subject: nucl-th daily 9 new + 4 crosses received by eprepget ------------------------------------------------------------------------------ ------------------------------------------------------------------------------ Send any comments regarding submissions directly to submitter. ------------------------------------------------------------------------------ Archives at http://arxiv.org/ To unsubscribe, e-mail To: nucl-th@arXiv.org, Subject: cancel ------------------------------------------------------------------------------ received by eprepget from Tue 28 Sep 10 20:00:00 GMT to Wed 29 Sep 10 20:00:00 GMT ------------------------------------------------------------------------------ \\ arXiv:1009.5697 Date: Tue, 28 Sep 2010 20:58:48 GMT (1914kb,D) Title: Instantaneous Shape Sampling - a model for the $\gamma$-absorption cross section of transitional nuclei Authors: I. Bentley, S. Brant, F. Doenau, S. Frauendorf, B. Kampfer, R. Schwengner, and S. Zhang Categories: nucl-th \\ The influence of the quadrupole shape fluctuations on the dipole vibrations in transitional nuclei is investigated in the framework of the Instantaneous Shape Sampling Model, which combines the Interacting Boson Model for the slow collective quadrupole motion with the Random Phase Approximation for the rapid dipole vibrations. Coupling to the complex background configurations is taken into account by folding the results with a Lorentzian with an energy dependent width. The low-energy energy portion of the $\gamma$- absorption cross section, which is important for photo-nuclear processes, is studied for the isotopic series of Kr, Xe, Ba, and Sm. The experimental cross sections are well reproduced. The low-energy cross section is determined by the Landau fragmentation of the dipole strength and its redistribution caused by the shape fluctuations. Collisional damping only wipes out fluctuations of the absorption cross section, generating the smooth energy dependence observed in experiment. In the case of semi-magic nuclei, shallow pygmy resonances are found in agreement with experiment. \\ ( http://arxiv.org/abs/1009.5697 , 1914kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5754 Date: Wed, 29 Sep 2010 02:45:14 GMT (25kb) Title: Compositeness of bound states in chiral unitary approach Authors: Tetsuo Hyodo (Tokyo Inst. Tech.), Daisuke Jido (YITP, Kyoto Univ.), Atsushi Hosaka (RCNP, Osaka Univ.) Categories: nucl-th hep-ph Comments: 5 pages, 2 figures, talk give at Chiral10 Workshop, June 21-24, 2010, Valencia Univ \\ We study the structure of dynamically generated bound states in the chiral unitary approach. The compositeness of a bound state is defined through the wavefunction renormalization constant in the nonrelativistic field theory. We apply this argument to the chiral unitary approach and derive the relation between compositeness of the bound state and the subtraction constant of the loop integral. The compositeness condition is fairly compatible with the natural renormalization scheme, previously introduced in a different context. \\ ( http://arxiv.org/abs/1009.5754 , 25kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5782 Date: Wed, 29 Sep 2010 06:48:53 GMT (220kb) Title: Stability of the fragments and thermalization at peak center-of-mass energy Authors: Aman D. Sood and Sukhjit Kaur Categories: nucl-th \\ We simulate the central reactions of nearly symmetric, and asymmetric systems, for the energies at which the maximum production of IMFs occurs (E$_{c.m.}^{peak}$).This study is carried out by using hard EOS along with cugnon cross section and employing MSTB method for clusterization. We study the various properties of fragments. The stability of fragments is checked through persistence coefficient and gain term. The information about the thermalization and stopping in heavy-ion collisions is obtained via relative momentum, anisotropy ratio, and rapidity distribution. We find that for a complete stopping of incoming nuclei very heavy systems are required. The mass dependence of various quantities (such as average and maximum central density, collision dynamics as well as the time zone for hot and dense nuclear matter) is also presented. In all cases (i.e., average and maximum central density, collision dynamics as well as the time zone for hot and dense nuclear matter) a power law dependence is obtained. \\ ( http://arxiv.org/abs/1009.5782 , 220kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5789 Date: Wed, 29 Sep 2010 07:23:42 GMT (169kb) Title: Photoproduction of K Sigma(1385) from the nucleon Authors: Yongseok Oh Categories: nucl-th hep-ph Comments: 4 pages, 3 figures, talk given at 12th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2010), Williamsburg, Virginia, 31 May - 4 Jun 2010 \\ The reactions of $K \Sigma(1385)$ photoproduction, i.e., $\gamma p \to K^+ \Sigma^0(1385)$ and $\gamma n \to K^+ \Sigma^-(1385)$, are investigated in the resonance energy region for studying the role of the nucleon and $\Delta$ resonances of masses around 2 GeV. The Lagrangians for describing the decays of these resonances into the $K \Sigma(1385)$ channel are constructed and the decay amplitudes are obtained, which allows us to determine the coupling constants using the predictions of quark models or the data listed by the Particle Data Group. The resulting cross sections are compared to the data from the Thomas Jefferson National Accelerator Facility and the SPring-8, which indicates nontrivial contributions from the two-star-rated resonances in the Particle Data Group as well as from some missing resonances predicted by a quark model. \\ ( http://arxiv.org/abs/1009.5789 , 169kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5895 Date: Wed, 29 Sep 2010 14:38:17 GMT (830kb) Title: Few-body decay and recombination in nuclear astrophysics Authors: A.S. Jensen, D.V. Fedorov, R. de Diego, E. Garrido and R. Alvarez-Rodriguez Categories: nucl-th Comments: 9 pages, 8 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 2010 \\ Three-body continuum problems are investigated for light nuclei of astrophysical relevance. We focus on three-body decays of resonances or recombination via resonances or the continuum background. The concepts of widths, decay mechanisms and dynamic evolution are discussed. We also discuss results for the triple $\alpha$ decay in connection with $2^+$ resonances and density and temperature dependence rates of recombination into light nuclei from $\alpha$-particles and neutrons. \\ ( http://arxiv.org/abs/1009.5895 , 830kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5924 Date: Wed, 29 Sep 2010 15:46:35 GMT (661kb) Title: A dynamical model of surrogate reactions Authors: Y. Aritomo, S. Chiba and K. Nishio Categories: nucl-th nucl-ex Comments: 17 pages, 5 figures \\ A new dynamical model is developed to describe the whole process of surrogate reactions; transfer of several nucleons at an initial stage, thermal equilibration of residues leading to washing out of shell effects and decay of populated compound nuclei are treated in a unified framework. Multi-dimensional Langevin equations are employed to describe time-evolution of collective coordinates with a time-dependent potential energy surface corresponding to different stages of surrogate reactions. The new model is capable of calculating spin distributions of the compound nuclei, one of the most important quantity in the surrogate technique. Furthermore, various observables of surrogate reactions can be calculated, e.g., energy and angular distribution of ejectile, and mass distributions of fission fragments. These features are important to assess validity of the proposed model itself, to understand mechanisms of the surrogate reactions and to determine unknown parameters of the model. It is found that spin distributions of compound nuclei produced in $^{18}$O+$^{238}$U $\rightarrow ^{16}$O+$^{240*}$U and $^{18}$O+$^{236}$U $\rightarrow ^{16}$O+$^{238*}$U reactions are equivalent and much less than 10$\hbar$, therefore satisfy conditions proposed by Chiba and Iwamoto (PRC 81, 044604(2010)) if they are used as a pair in the surrogate ratio method. \\ ( http://arxiv.org/abs/1009.5924 , 661kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5951 Date: Wed, 29 Sep 2010 17:31:34 GMT (350kb) Title: Viscosity, entropy and the viscosity to entropy density ratio; how perfect is a nucleonic fluid? Authors: Aram Z. Mekjian Categories: nucl-th Comments: 32 pages, 9 figures \\ The viscosity of hadronic matter is studied using a classical evaluation of the scattering angle and a quantum mechanical discussion based on phase shifts from a potential. Semi classical limits of the quantum theory are presented. A hard sphere and an attractive square well potential step are each considered as well as the combined effects of both. The lowest classical value of the viscosity for an attractive potential is shown to be a hard sphere limit. The high wave number-short wavelength limits of the quantum result have scaling laws associated with it for both the viscosity and entropy. These scaling laws are similar to the Fraunhoher diffraction increase for the hard sphere geometric cross section. Specific examples for nuclear collisions are given. The importance of the nuclear tensor force and hard core is mentioned. The viscosity (eta), entropy density (s) and eta/s ratio are calculated for a gas of dilute neutrons in the unitary limit of large scattering length. Away from the unitary limit, the ratio of the interaction radius or the scattering length to the interparticle spacing introduces a variable y besides the fugacity z. The isothermal compressibility is shown to impose important constraints. The results for eta/s are compared to the AdS/CFT string theory minimum of (1/4Pi)hbar/kb to see how close a nucleonic gas is to being a perfect fluid. The eta/s ~1hbar/kb for a neutron gas in its unitary limit. The eta/s 3hbar/kb treating the nuclear scattering as billiard ball collisions. The minimum eta/s for a neutron gas occurs in regions of negative isothermal compressibility and high fugacity where higher virial terms are important. In a neutron-proton system higher virial terms are associated with a liquid-gas phase transition and critical opalescent phenomena.The type of flow-laminar,vortex, turbulent- is investigated. \\ ( http://arxiv.org/abs/1009.5951 , 350kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5960 Date: Wed, 29 Sep 2010 18:01:48 GMT (171kb) Title: Meson-baryon interaction in the meson exchange picture Authors: M. D\"oring Categories: nucl-th Comments: 4 pages, contribution to the proceedings of the MENU 2010 conference, May 31- June 4, 2010, Williamsburg VA, USA \\ This is the contribution to the proceedings of the MENU 2010 conference. The recent work of Ref. [7] is summarized. Elastic piN scattering and the reaction pi^+ p --> K^+ Sigma^+ are described simultaneously in a unitary coupled-channels approach which respects analyticity. SU(3) flavor symmetry is used to relate the t- and u- channel exchanges that drive the meson-baryon interaction in the different channels. Angular distributions, polarizations, and spin-rotation parameters are compared with available experimental data. The pole structure of the amplitudes is extracted from the analytic continuation. \\ ( http://arxiv.org/abs/1009.5960 , 171kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5984 Date: Wed, 29 Sep 2010 19:51:02 GMT (37kb) Title: Three-body forces and shell structure in calcium isotopes Authors: Jason D. Holt, Takaharu Otsuka, Achim Schwenk, Toshio Suzuki Categories: nucl-th astro-ph.SR hep-ph nucl-ex Comments: 4 pages, 4 figures \\ Understanding and predicting the formation of shell structure from nuclear forces is a central challenge for nuclear physics. While the magic numbers N=2,8,20 are generally well understood, N=28 is the first standard magic number that is not reproduced in microscopic theories with two-nucleon forces. In this Letter, we show that three-nucleon forces give rise to repulsive interactions between two valence neutrons that correctly lead to 48Ca as a magic nucleus, with a high 2+ excitation energy and a concentrated magnetic dipole transition strength. Towards the neutron drip line, we robustly predict a shell closure at N=34. The repulsive three-nucleon mechanism improves the agreement with experimental binding energies and suggests the drip line around 60Ca. \\ ( http://arxiv.org/abs/1009.5984 , 37kb) %-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%-%- ------------------------------------------------------------------------------ \\ arXiv:1009.5154 (*cross-listing*) Date: Mon, 27 Sep 2010 04:14:51 GMT (241kb,D) Title: Renormalized Linear Kinetic Theory as Derived from Quantum Field Theory --- a novel diagrammatic method for computing transport coefficients --- Authors: Yoshimasa Hidaka and Teiji Kunihiro Categories: hep-ph nucl-th Comments: 17 pages, 6 figures Report-no: KUNS-2301 \\ We propose a novel diagrammatic method for computing transport coefficients in relativistic quantum field theory. Our method is based on a reformulation and extension of the diagrammatic method by Eliashberg given in the imaginary-time formalism to the relativistic quantum field theory. It is known that although transport coefficients are expressed as specific two-point functions via Kubo formula, naive perturbation theory based on loop expansions for computing the two-point functions breaks down owing to the so called pinch singularity, and hence resummation is required for getting a finite and sensible result. In our novel resummation method, we first identify diagrams with the pinch singularity and decompose the two-point function into a singular and a regular part diagrammatically, and then the diagrams with the singularity are resummed using a self-consistent equation or an integral equation. We confirm that the self-consistent equation in the leading order of the coupling constant gives a kinetic equation with the same form of a linearized Boltzmann equation, which is known in the literature. Our formalism provides us with a transparent way for the systematic incorporation of higher order corrections to the kinetic equation and hence the transport coefficients for the first time. We find that the higher-order corrections are nicely summarized into those to the vertex functions, spectral function, and collision term. \\ ( http://arxiv.org/abs/1009.5154 , 241kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5781 (*cross-listing*) Date: Wed, 29 Sep 2010 06:42:33 GMT (249kb) Title: Transversity relations, chiral and holographic models, and pion wave functions from lattice QCD Authors: Enrique Ruiz Arriola and Wojciech Broniowski Categories: hep-ph hep-lat nucl-th Comments: 8 pages, 2 figures, talk presented by ERA at Light Cone 2010, Valencia, 14-18 June 2010 \\ We analyze the equal-time Bethe-Salpeter quark wave functions of the pion in various models. We discuss how the quenched lattice QCD results with delocalized pion interpolators can be identified with the coarse grained wave functions, typical of low-energy effective models. Actually, we find that one-loop chiral quark models predict that pseudoscalar and tensor wave functions have the same shape, while the axial component is more extended. These facts are accurately confirmed by the lattice. We also show how the transversity information, relevant for the light-cone physics, can be straightforwardly obtained from the equal-time rest-frame lattice calculations. This remarkable relation provides a way to extract, for instance, the equal-time holographic wave functions and compare them, quite favorably, to the lattice calculations. \\ ( http://arxiv.org/abs/1009.5781 , 249kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5881 (*cross-listing*) Date: Wed, 29 Sep 2010 13:50:22 GMT (326kb,D) Title: Disentangling correlations in Multiple Parton Interactions Authors: Giorgio Calucci and Daniele Treleani Categories: hep-ph nucl-th Comments: 22 pages, 8 figures \\ Multiple Parton Interactions are the tool to obtain information on the correlations between partons in the hadron structure. Partons may be correlated in all different degrees of freedom and all different correlation terms contribute to the cross section. The contributions due to the different parton flavors can be isolated, at least to some extent, by selecting properly the final state. In the case of high energy proton-proton collisions, the effects of correlations in the transverse coordinates and in fractional momenta are, on the contrary, unavoidably mixed in the final observables. A small value of the effective cross section may be originated by the relatively short transverse distance between the pairs of partons undergoing the double interaction or by a large dispersion of the distribution in multiplicity of the multi-parton distributions. The aim of the present paper is to show how the effects of longitudinal and transverse correlations may be disentangled by taking into account the additional information provided by double parton interactions in high energy proton-deuteron collisions. \\ ( http://arxiv.org/abs/1009.5881 , 326kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5935 (*cross-listing*) Date: Wed, 29 Sep 2010 16:32:30 GMT (68kb) Title: QCD at non-zero temperature: bulk properties and heavy quarks Authors: P. Petreczky Categories: hep-lat hep-ph nucl-th Comments: LaTeX, 12 pages, 6 figures. Invited brief review for Modern Physics Letters A \\ I review recent progress in lattice QCD at non-zero temperature whith emphasis on the calculations of equation of state and the properties of heavy quar anti-quark pairs at high temperatures. I also briefly discuss the deconfinement and chiral symmetry restoring aspects of the QCD transition at finite temperature \\ ( http://arxiv.org/abs/1009.5935 , 68kb) %%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%%--%% ------------------------------------------------------------------------------ \\ arXiv:1009.1483 replaced with revised version Wed, 29 Sep 2010 15:23:35 GMT (0kb,I) Title: Multi-Hyper-Nuclei Production in Anti-Proton Induced Reactions within a Microscopic Transport Approach Authors: Timo Spielmann, Ayut Limphirat, Chinorat Kobdaj, Yupeng Yan Categories: nucl-th Comments: This paper has been withdrawn by the authors. we do not pulish this \\ ( http://arxiv.org/abs/1009.1483 , 0kb) ------------------------------------------------------------------------------ \\ arXiv:1009.4161 replaced with revised version Wed, 29 Sep 2010 10:20:31 GMT (642kb) Title: Low scale saturation of Effective NN Interactions and their Symmetries Authors: E. Ruiz Arriola Categories: nucl-th hep-ph Comments: 5 pages, 3 figures. Typos corrected \\ ( http://arxiv.org/abs/1009.4161 , 642kb) ------------------------------------------------------------------------------ \\ arXiv:1009.5666 (*cross-listing*) replaced with revised version Wed, 29 Sep 2010 19:05:35 GMT (15kb) Title: Short Range Correlations and the EMC Effect Authors: L.B. Weinstein, E. Piasetzky, D.W. Higinbotham, J. Gomez, O. Hen, and R. Shneor Categories: hep-ph nucl-ex nucl-th Comments: 5 pages, 2 figures, minor changes for PRL submission \\ ( http://arxiv.org/abs/1009.5666 , 15kb) %%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%---%%%--- For subscribe options to combined physics archives, e-mail To: physics@arXiv.org, Subject: subscribe ----------------------------------------------------------------------------- For help on viewing and making submissions, see http://arXiv.org/help/ For a list of archive mirror sites, see http://arXiv.org/servers.html ----------------------------------------------------------------------------- Third-party submissions cause excessive problems. Author self-submissions are exceedingly preferred. E-mail submissions have been discontinued in favor of better support for Web submissions. See http://arXiv.org/help/uploads