Bulletin of the American Physical Society
2017 Fall Meeting of the APS Division of Nuclear Physics
Volume 62, Number 11
Wednesday–Saturday, October 25–28, 2017; Pittsburgh, Pennsylvania
Session HJ: Nuclear Theory I |
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Chair: Charlotte Elster, Ohio University Room: City Center A |
Friday, October 27, 2017 8:30AM - 8:42AM |
HJ.00001: Isospin and Isospin-less Models for Kaonic Clusters Branislav Vlahovic, Igor Filikhin The kaonic clusters KKp and ppK are studied based on the configuration space Faddeev equations formulated for AAB system. We consider two models: isospin and isospin-less. The relations between the doubled binding energy of the AB subsystem 2B2 and the three-body binding energy B3(VAA$=$0), when the interaction between the identical particles is omitted, are different for these models. For the kaonic cluster described within isospin formalism the relation B3(VAA$=$0) \textless 2B2 is valid. The evaluation for the ppK binding energy B3 \textless 2B2 is result of a weak attraction of the spin singlet NN interaction. The isospin-less model leads to the relation B3(VAA$=$0) \textgreater 2B2. The results of calculations are presented. [Preview Abstract] |
Friday, October 27, 2017 8:42AM - 8:54AM |
HJ.00002: Pion-less effective field theory for real and lattice nuclei Aaina Bansal, Sven Binder, Andreas Ekstr\"om, Gaute Hagen, Thomas Papenbrock We compute the medium-heavy nuclei $^{16}$O and $^{40}$Ca using pion-less effective field theory (EFT) at leading order (LO) and next-to-leading order (NLO). The low-energy coefficients of the EFT Hamiltonian are adjusted to $A=2,3$ nuclei data from experiments, or alternatively to data from lattice QCD at unphysical pion mass $m_{\pi} = 806$~MeV. The EFT is implemented through discrete variable representation of finite harmonic oscillator basis. This approach ensures rapid convergence with respect to the size of the model space and allows us to compute heavier atomic and lattice nuclei. The atomic nuclei $^{16}$O and $^{40}$Ca are bound with respect to decay into alpha particles at NLO, but not at LO. [Preview Abstract] |
Friday, October 27, 2017 8:54AM - 9:06AM |
HJ.00003: Consistent Renormalization of NN Interactions and Operators Robert Basili, Weijie Du, Soham Pal, Shiplu Sarker, Pieter Maris, James Vary We investigate the effects of consistent renormalization on observables for bound states of two nucleon systems, both the deuteron and systems within external harmonic traps. The observables under investigation are the Hamiltonian, root-mean-square radius, electric quadrupole moment, magnetic dipole moment, Gamow-Teller decay, and neutrinoless double $\beta$-decay. We renormalize these operators to different model P-spaces by the Okubo-Lee-Suzuki (OLS) transformation. We adopt the chiral effective field theory (EFT) NN interactions available up to N4LO (E. Epelbaum, H. Krebs and U. G. Meissner, Phys. Rev. Lett. 115, 122301 (2015)). For the neutrinoless double $\beta$-decay operator we implement a chiral EFT operator through NLO (G. Prezeau, M. Ramsey-Musolf and P. Vogel, Phys. Rev. D 68, (2003)), whereas for the other observables, we use bare operators. We show the differences of each effective operator from its corresponding bare operator in the model P-spaces. [Preview Abstract] |
Friday, October 27, 2017 9:06AM - 9:18AM |
HJ.00004: Electric properties of one-neutron halo nuclei in Halo EFT Jonas Braun, Hans-Werner Hammer We exploit the separation of scales in weakly-bound nuclei to compute E2 transitions and electric radii in a Halo EFT framework. The relevant degrees of freedom are the core and the halo neutron. The EFT expansion is carried out in powers of $R_{core}/R_{halo}$, where $R_{core}$ and $R_{halo}$ denote the core and halo radius, respectively. We include the strong s-wave and d-wave interactions by introducing dimer fields. The dimer propagators are regulated by employing the power-law divergence subtraction scheme and matched to the effective-range expansion in the respective channel. Electromagnetic interactions are included via minimal substitution in the Lagrangian. We demonstrate that, depending on the observable and respective partial wave, additional local gauge-invariant operators contribute in LO, NLO and higher orders. Finally, we present the modifications needed for the extension of our work to higher partial-wave bound states and discuss the consequences for universality in such systems. [Preview Abstract] |
Friday, October 27, 2017 9:18AM - 9:30AM |
HJ.00005: Bayesian truncation errors in chiral effective field theory: model checking and accounting for correlations Jordan Melendez, Sarah Wesolowski, Dick Furnstahl Chiral effective field theory (EFT) predictions are necessarily truncated at some order in the EFT expansion, which induces an error that must be quantified for robust statistical comparisons to experiment. A Bayesian model yields posterior probability distribution functions for these errors based on expectations of naturalness encoded in Bayesian priors and the observed order-by-order convergence pattern of the EFT [1]. As a general example of a statistical approach to truncation errors, the model was applied to chiral EFT for neutron-proton scattering using various semi-local potentials of Epelbaum, Krebs, and Mei{\ss}ner (EKM). Here we discuss how our model can learn correlation information from the data and how to perform Bayesian model checking to validate that the EFT is working as advertised. [1] arXiv:1704.03308 submitted to PRC (in press). [Preview Abstract] |
Friday, October 27, 2017 9:30AM - 9:42AM |
HJ.00006: On HQET and NRQCD Operators of Dimension 8 and Above Ayesh Gunawardana, Gil Paz Effective field theories such as Heavy Quark Effective Theory (HQET) and Non Relativistic Quantum Chromo-(Electro-) dynamics NRQCD (NRQED) are indispensable tools for controlling the effects of the strong interaction. The increasing experimental precision requires the knowledge of higher dimensional operators. These operators are important to the evaluation of decay rates of the B-meson. We present a general method that allows for an easy construction of HQET (NRQED and NRQCD) operators that contain two heavy quark (non-relativistic) fields and any number of covariant derivatives. As an application of our method, we give for the first time all such terms in the $1/M^4$ NRQCD Lagrangian, where $M$ is the mass of the spin-half field. We analyze the general dimension-nine spin-independent HQET matrix element, which was not considered so far in the literature, and calculate moments of the leading power shape function up to and including dimension nine HQET operators. [Preview Abstract] |
Friday, October 27, 2017 9:42AM - 9:54AM |
HJ.00007: Non-Local Translationally Invariant {\it Ab Initio} One-Body Density Matrices Matthew Burrows, Charlotte Elster, Gabriela Popa, Andreas Nogga, Kristina Launey, Pieter Maris A derivation of microscopic effective interactions (optical potentials) between nucleons and a nucleus requires in first order aside from the NN interaction a non-local {\it ab initio} one-body density matrix for the target nucleus which is translationally invariant. We obtained non-local one-body density matrices from no-core shell-model (NCSM) calculations based on the JISP16 NN interaction for $^4$He, $^6$He, and $^6$Li as well as from a symmetry-adapted NCSM for $^{12}$C using the same interaction. We present how the center-of-mass inherent in the NCSM calculation is removed exactly for non-local one-body density matrices. We further explore the nature of the non-locality and compare with commonly used approximations for this non-locality. [Preview Abstract] |
Friday, October 27, 2017 9:54AM - 10:06AM |
HJ.00008: Finite-Temperature Relativistic Time-Blocking Approximation for Nuclear Strength Functions. Herlik Wibowo, Elena Litvinova This work presents an extension of the relativistic nuclear field theory (RNFT) developed throughout the last decade as an approach to the nuclear many-body problem, based on QHD meson-nucleon Lagrangian and relativistic field theory. The unique feature of RNFT is a consistent connection of the high-energy scale of heavy mesons, the medium-energy range of pion, and the low-energy domain of emergent collective vibrations (phonons). RNFT has demonstrated a very good performance in various nuclear structure calculations across the nuclear chart and, in particular, provides a consistent input for description of the two phases of r-process nucleosynthesis: neutron capture and beta decay. Further inclusion of finite temperature effects presented here allows for an extension of the method to highly excited compound nuclei. The covariant response theory in the relativistic time-blocking approximation (RTBA) is generalized for thermal effects, adopting the Matsubara Green's function formalism to the RNFT framework. The finite-temperature RTBA is implemented numerically to calculate multipole strength functions in medium-mass and heavy nuclei. The obtained results will be discussed in comparison to available experimental data and in the context of possible consequences for astrophysics. [Preview Abstract] |
Friday, October 27, 2017 10:06AM - 10:18AM |
HJ.00009: The Model of Complex Structure of Quark Rongwu Liu In Quantum Chromodynamics, quark is known as a kind of point-like fundamental particle which carries mass, charge, color, and flavor, strong interaction takes place between quarks by means of exchanging intermediate particles---gluons. An important consequence of this theory is that, strong interaction is a kind of short-range force, and it has the features of ``asymptotic freedom'' and ``quark confinement''. In order to reveal the nature of strong interaction, the ``bag'' model of vacuum and the ``string'' model of string theory were proposed in the context of quantum mechanics, but neither of them can provide a clear interaction mechanism. This article formulates a new mechanism by proposing a model of complex structure of quark, it can be outlined as follows: (1) Quark (as well as electron, etc) is a kind of complex structure, it is composed of fundamental particle (fundamental matter mass and electricity) and fundamental volume field (fundamental matter flavor and color) which exists in the form of limited volume; fundamental particle lies in the center of fundamental volume field, forms the ``nucleus'' of quark. (2) As static electric force, the color field force between quarks has classical form, it is proportional to the square of the color quantity carried by each color field, and inversely proportional to the area of cross section of overlapping color fields which is along force direction, it has the properties of overlap, saturation, non-central, and constant. (3) Any volume field undergoes deformation when interacting with other volume field, the deformation force follows Hooke's law. (4) The phenomena of ``asymptotic freedom'' and ``quark confinement'' are the result of color field force and deformation force. [Preview Abstract] |
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