Bulletin of the American Physical Society
2011 Fall Meeting of the APS Division of Nuclear Physics
Volume 56, Number 12
Wednesday–Saturday, October 26–29, 2011; East Lansing, Michigan
Session GA: Nuclear Theory I: RHI, EMC, Beta-decay |
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Chair: Vladimir Zelevinsky, Michigan State University Room: 62 |
Friday, October 28, 2011 8:30AM - 8:42AM |
GA.00001: Medium Induced Collinear Radiation via Soft Collinear Effective Theory (SCET) Francesco D'Eramo, Hong Liu, Krishna Rajagopal The propagation of hard partons through the strongly interacting matter created in high energy heavy-ion collisions involves widely separated scales. The methods of Effective Field Theories (EFT) can provide a factorized description at lowest nontrivial order, and a formalism where the correction to this factorization are calculable systematically order by order in the small ratios between the different scales. In this talk I will present our preliminary results on the medium induced collinear radiation by using the methods of Soft Collinear Effective Theory (SCET). The radiated gluon is collinear with the incoming hard parton and gets and arbitrary fraction of its energy. [Preview Abstract] |
Friday, October 28, 2011 8:42AM - 8:54AM |
GA.00002: Transverse Momentum Broadening in Weakly Coupled Quark-Gluon Plasma Mindaugas Lekaveckas, Krishna Rajagopal, Hong Liu, Francesco D'Eramo, Christopher Lee Jet quenching parameter or, equivalently, transverse momentum broadening distribution function is an important quantity which helps to understand energy losses in heavy ion collisions and get insights into the properties of the de-confined quark- gluon plasma. Soft Collinear Effective Theory (SCET) provides framework to calculate jet quenching parameter at weak coupling using expectation value of two space-like separated light-like Wilson lines which can be evaluated for desired medium. In this work we obtain transverse momentum broadening distribution function for the quark- gluon plasma in equilibrium using full Thermal Field Theory formalism and recover its limiting behavior in the HTL regime. [Preview Abstract] |
Friday, October 28, 2011 8:54AM - 9:06AM |
GA.00003: ABSTRACT WITHDRAWN |
Friday, October 28, 2011 9:06AM - 9:18AM |
GA.00004: Nuclear Scaling at Low Resolution E.R. Anderson, S.K. Bogner, R.J. Furnstahl, K. Hebeler, R.J. Perry Nuclear scaling is observed in the ratios of inclusive electron scattering on different nuclei for \(1.5\leq x_{B}\leq2.0\) at large momentum transfer \(Q^{2}\). The ratios depend on the nucleus but are independent of \(Q^{2} \), and have been understood to be a result of strong short- range correlations induced by the nucleon-nucleon interaction. Recent calculations of nuclear structure make use of the similarity renormalization group to soften the nuclear potential through a series of unitary transformations, which suppress short range correlations.\footnote{E.D. Jurgenson, P. Navr\'atil, and R.J. Furnstahl, Phys. Rev. Lett. \textbf{103}, 082501 (2009).}\(^{,}\)\footnote{E. R. Anderson, S. K. Bogner, R. J. Furnstahl, and R. J. Perry, Phys. Rev. C \textbf{82}, 054001 (2010)} However, we can now understand and calculate this scaling ratio as an effect of low momentum nuclear structure via factorization of operator expectation values. We also apply this framework to an observed correlation with the EMC effect.\footnote{L. B. Weinstein \textit{et al.}, Phys. Rev. Lett. \textbf{106}, 052301 (2011)} [Preview Abstract] |
Friday, October 28, 2011 9:18AM - 9:30AM |
GA.00005: The onset of proton-neutron correlations in nuclei Mihai Horoi Proton-neutron correlations in nuclei can be explained in part by isosclar and isovector pairing. Shell model techniques reveal additional strong proton-neutron correlations that were recently observed in neutron transfer reactions. I will discuss the pieces of the effective interaction that contribute to these strong correlations. I will also show the the observed $1^+0$ and $0+1$ low-lying states in odd-odd nuclei are geometrically favored in the two-body random ensemble model. [Preview Abstract] |
Friday, October 28, 2011 9:30AM - 9:42AM |
GA.00006: Spectroscopy of the hadronic atoms and superheavy isotopes: Energy shifts and strong K, pi- N interaction corrections Olga Khetselius, Inga Serga, Anastasiya Shakhman Ab initio many-body perturbation theory approach with an accurate account of relativistic, nuclear, radiative effects is used in calculating spectra of some hadronic (pion, kaon) atoms. One of the main purposes is establishment a quantitative link between quality of nucleus structure modeling and accuracy of calculating energy and spectral properties. The wave functions zeroth basis is found from the Klein-Gordon-Fock equation for hadronic system and the Dirac-Fock equation for usual atom. The potential includes the SCF ab initio potential, the electric and polarization potentials of a nucleus (the RMF and Fermi models for a charge distribution in a nucleus are considered). For low orbits there are the important effects due to the strong hadron-nuclear interaction. We present the data on: the energy levels for superheavy isotopes Z=113,114 and the shifts and widths of transitions (2p-1s,3d-2p, 4f-3d etc) in some pionic and kaonic atoms (H, He, N, W, U). The calculated X-ray transitions spectrum for kaonic He and estimate of 2p level shift due to the strong K-N interaction 1.57 eV are in the reasonable agreement with experiment (the shift 1.9eV) by Okada et al (2008; E570; KEK 12GeV, RIKEN Nishina Centre, JAPAN) and differ (about order) of other experimental data by Wiegand-Pehl (1971), Batty et al (1979), Baird et al (1983). [Preview Abstract] |
Friday, October 28, 2011 9:42AM - 9:54AM |
GA.00007: Advances in the calculation of double beta decay J. Kotila, F. Iachello The fundamental nature and the absolute mass scale of the neutrino is a subject of great interest at the present. In order to study these issues the nuclear $\beta\beta$-decay is utilized. For an extraction of the neutrino mass and for estimates of the half-life, besides the involved nuclear matrix elements, one also needs the phase-space factors $G_{0\nu}$ and $G_{2\nu}$. A general formulation was given by Doi et al. [1]. However, in previous calculations an approximate expression for the electron wave function at the nucleus is used. We have done an independent calculation with exact Dirac electron wave functions including screening by the electron cloud [2]. The influence to the phase-space factors is seen especially for the heavier $\beta\beta$-decaying nuclei. This is an extremely important observation since, judging by the expected lifetime, $^{150}$Nd is one of the most prominent candidates where the $0\nu\beta\beta$-decay could be seen. Furthermore, we have calculated the phase-space factors to the first excited $0^+$ state both in $0\nu$ and $2\nu$ mode. All the above mentioned results are combined with recently calculated IBM-2 nuclear matrix elements [3] leading to a more reliable prediction for neutrino mass and estimates of the half-life in both modes. [1] M. Doi et al., Prog. Theor. Phys. 66 (1981) 1739. [2] J. Kotila and F. Iachello, to be published. [3] J. Barea and F. Iachello, Phys. Rev. C79 (2009) 044301 and to be published. [Preview Abstract] |
Friday, October 28, 2011 9:54AM - 10:06AM |
GA.00008: The beta-decay properties in the vicinity of $^{78}$Ni Ivan N. Borzov The beta-decay properties of neutron-rich Cu to Ga nuclei in the vicinity of the doubly magic $^{78}$Ni have been calculated within the density-functional approach plus continuum QRPA (DF+CQRPA) [1]. The framework allows for a fully microscopic description of the Gamow-Teller (GT) and first forbidden (FF) transitions between $dsgh$ and $fpp$ shells. The new theoretical predictions are compared with our previous ones, with the standard FRDM calculations [2] and recent experimental data. Of particular importance are new high quality gamma ray spectroscopy data obtained for Zn to Ga isotopes with N$>$50 at Holifield Radioactive Ion Beam Facility (HRIBF). In $^{78}$Ni region, the half-lives calculated with blocking of the odd-proton on the 1pf$_{5/2}$-orbital agrees with the data better than the ones with no blocking as well as the ones from standard FRDM calculations used for the r-process modeling. The high-energy first forbidden transitions in the nuclei with N$>$50 populating low lying excited levels in the daughter nuclei produce a strong impact on the total half- lives and especially on the delayed neutron emission. The effect of reduction of the Pn-values compared to the pure GT- approximation in N$>$50 isotopes [1] will be discussed.\\[0pt] [1] I.N. Borzov, Phys. Rev. C 67, 025802 (2003); Phys. Rev. C 71, 065801 (2003). [2] P. Moeller, B. Pfeiffer and K-L Kratz, Phys. Rev. C 67, 055802 (2003). [Preview Abstract] |
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