Nuclear Theory·nucl-th

Wednesday·December 28, 2016

10 papers—6 primary·4 cross-listed

01
The deuteron wave function and neutron form factors from the elastic electron deuteron scattering
N.A. Khokhlov
A study of the deuteron structure in the framework of relativistic quantum mechanics is presented. Point-form (PF) relativistic quantum mechanics (RQM) is applied to the elastic eD scattering. The deuteron wave function and neutron form factors are fitted to the electromagnetic deuteron form factors. We also compare results obtained by different realistic deuteron wave functions stemming from Nijmegen-I, Nijmegen-II, JISP16, CD-Bonn, Paris, Argonne, Idaho and Moscow (with forbidden states) potentials. It is shown that the electromagnetic deuteron form factors may be described without exchange currents.
nucl-th2 citations
02
In-Medium Similarity Renormalization Group Approach to the Nuclear Many-Body Problem
H. Hergert🇺🇸 · S. K. Bogner🇺🇸 · J. G. Lietz🇺🇸 · T. D. Morris🇺🇸 · S. J. Novario🇺🇸 · N. M. Parzuchowski🇺🇸 · F. Yuan🇺🇸
We present a pedagogical discussion of Similarity Renormalization Group (SRG) methods, in particular the In-Medium SRG (IMSRG) approach for solving the nuclear many-body problem. These methods use continuous unitary transformations to evolve the nuclear Hamiltonian to a desired shape. The IMSRG, in particular, is used to decouple the ground state from all excitations and solve the many-body Schrödinger equation. We discuss the IMSRG formalism as well as its numerical implementation, and use the method to study the pairing model and infinite neutron matter. We compare our results with those of Coupled cluster theory, Configuration-Interaction Monte Carlo, and the Self-Consistent Green's Function approach. The chapter concludes with an expanded overview of current research directions, and a look ahead at upcoming developments.
nucl-thnucl-exLect.Notes Phys.(2017)·27 citations
03
Leading order relativistic hyperon-nucleon interactions in chiral effective field theory
Kai-Wen Li🇨🇳 · Xiu-Lei Ren🇨🇳 · Li-Sheng Geng🇨🇳 · Bing-Wei Long🇨🇳
We apply a recently proposed covariant power counting in nucleon-nucleon interactions to study strangeness $S = - 1$ $Λ N - Σ N$ interactions in chiral effective field theory. At leading order, Lorentz invariance introduces 12 low energy constants, in contrast to the heavy baryon approach, where only five appear. The Kadyshevsky equation is adopted to resum the potential in order to account for the non-perturbative nature of hyperon-nucleon interactions. A fit to the $36$ hyperon-nucleon scattering data points yields $χ^{2} ≃ 16$ , which is comparable with the sophisticated phenomenological models and the next-to-leading order heavy baryon approach. However, one cannot achieve a simultaneous description of the nucleon-nucleon phase shifts and strangeness $S = - 1$ hyperon-nucleon scattering data at leading order.
nucl-thhep-phCPC(2018)·59 citations
04
Collective Excitations in Hot QCD Plasma
Navid Abbasi🇮🇷 · Davood Allahbakhshi🇮🇷 · Ali Davody🇩🇪 · Seyed Farid Taghavi🇮🇷
We study the long wavelength excitations in rotating QCD fluid in presence of an external magnetic field at finite vector and axial charge densities. We consider the fluctuations of vector and axial charge currents coupled to energy and momentum fluctuations and compute the $S O (3)$ covariant dispersion relations of the six corresponding hydrodynamic modes. Among them, there are always two scalar Chiral Magnetic-Vortical-Heat (CMVH) waves; In the absence of magnetic field (vorticity) these waves reduce to CVH (CMH) waves. While CMVH waves are the mixed of CMH and CVH waves, they have generally different velocities compared to the sum of velocities of the latter waves. The other four modes, which are made out of scalar-vector fluctuations, are mixed Sound-Alfvén waves. We show that in the direction parallel to both magnetic field and vorticity, these four modes are the two ordinary sound modes together with two Chiral Alfvén waves (CAW).
nucl-thhep-phhep-thPRD(2017)·13 citations
05
Refined Glauber model versus Faddeev calculations and experimental data for $p d$ spin observables
M. N. Platonova🇷🇺 · V. I. Kukulin🇷🇺
Spin-dependent observables in intermediate-energy $p d$ elastic scattering within the framework of the refined Glauber model are considered. The improvements include an account of all ten $pp$ and $p n$ helicity amplitudes at respective energies constructed on the basis of modern phase-shift analysis, accurate deuteron wave functions taken from the modern $N N$ force model and account of charge-exchange effects. Predictions of the refined diffraction model for the differential cross section and analyzing powers are compared with exact three-body Faddeev calculations and the recent experimental data. An amazingly good agreement between the results of both theoretical approaches as well as between the refined Glauber model and experiment in a wide angular range not only for differential cross section but also for vector and tensor analyzing powers has been found in the first time. Possible reasons for this agreement are discussed.
nucl-thPRC(2010)·51 citations
06
Energy Dependent Separable Optical Potentials for (d,p) Reactions
L. Hlophe · Ch. Elster
An important ingredient for applications of nuclear physics to e.g. astrophysics or nuclear energy are the cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not possible, indirect methods like $(d, p)$ reactions must be used instead. Those $(d, p)$ reactions may be viewed as effective three-body reactions and described with Faddeev techniques. An additional challenge posed by $(d, p)$ reactions involving heavier nuclei is the treatment of the Coulomb force. To avoid numerical complications in dealing with the screening of the Coulomb force, recently a new approach using the Coulomb distorted basis in momentum space was suggested. In order to implement this suggestion separable representations of neutron- and proton-nucleus optical potentials, which are not only complex but also energy dependent, need to be introduced. Including excitations of the nucleus in the calculation requires a multichannel optical potential, and thus separable representations thereof.
nucl-th0 citations
07
Triple parton scatterings in proton-nucleus collisions at high energies
David d'Enterria🇨🇭 · Alexander M. Snigirev🇷🇺
A generic expression to compute triple parton scattering (TPS) cross sections in high-energy proton-nucleus (pA) collisions is derived as a function of the corresponding single-parton cross sections and an effective parameter encoding the transverse parton profile of the proton. The TPS cross sections are enhanced by a factor of $9 A \approx 2000$ in pPb compared to those in proton-nucleon collisions at the same center-of-mass energy. Estimates for triple charm ( $c c$ ) and bottom ( $b b$ ) production in pPb collisions at LHC and FCC energies are presented based on next-to-next-to-leading order (NNLO) calculations for $c c, b b$ single-parton cross sections. At $s_{N N} = 8.8$ TeV, about 10% of the pPb events have three $c c$ pairs produced in separate partonic interactions. At $s_{N N} = 63$ TeV, the pPb cross sections for triple-J $/ ψ$ and triple- $b b$ are $O$ (1--10 mb). In the most energetic cosmic-ray collisions observed on earth, TPS $c c$ -pair cross sections equal the total p-Air inelastic cross section.
↳ hep-phastro-ph.HEhep-exnucl-ex+1EPJC(2018)·32 citations
08
Hyperon single-particle potentials from QCD on lattice
Takashi Inoue · for HAL QCD Collaboration
We study single-particle potential of hyperons in nuclear medium starting from QCD. First we carry out lattice QCD numerical simulation to extract baryon-baryon interactions from QCD by means of the HAL QCD method. We employ a full QCD gauge configuration ensemble at almost physical point so that hadron masses are nearly physical, e.g. pion mass is 146 MeV, kaon mass is 525 MeV, and nucleon mass is 956 MeV. Then, with some simplifications, we apply the obtained hyperon interactions to the Brueckner-Hartree-Fock theory and calculate single-particle potential of hyperons in nuclear medium $U_{Y} (ρ, k)$ . For the symmetric nuclear matter at the normal nuclear matter density, we obtain $U_{Λ} (ρ_{0}, 0) = - 33$ MeV, $U_{Σ} (ρ_{0}, 0) = + 11$ MeV, and $U_{Ξ} (ρ_{0}, 0) = - 6$ MeV. These results are qualitatively compatible with values suggested from experiments. This success is remarkable and encouraging because we are trying to reveal nature of baryon-baryon interactions starting from QCD, and this agreement proves that our approach is essentially correct.
↳ hep-lathep-phnucl-exnucl-thPoS(2016)·24 citations
09
Different pole structures in line shapes of the $X (3872)$
Xian-Wei Kang🇪🇸 · J. A. Oller🇪🇸
We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective-range because it can also handle with a near-threshold zero in the $D^{0} D ˉ^{* 0}$ $S$ -wave. In terms of it we analyze the CDF data on inclusive $p p ˉ$ scattering to $J / ψ π^{+} π^{-}$ , and the Belle and BaBar data on $B$ decays to $K J / ψ π^{+} π^{-}$ and $K D D ˉ^{* 0}$ around the $D^{0} D ˉ^{* 0}$ threshold. It is shown that data can be reproduced with similar quality for the $X (3872)$ being a bound {\it and/or} a virtual state. We also find that the $X (3872)$ might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small $D^{* 0}$ width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the $D^{* 0}$ width itself. The $X (3872)$ compositeness coefficient in $D^{0} D ˉ^{* 0}$ ranges from nearly 0 up to 1 in the different scenarios.
↳ hep-phhep-exnucl-thEPJC(2017)·104 citations
10
Effective field theories for quantum chromo- and electrodynamics
Ou Z. Labun🇺🇸
In this dissertation, I introduce the principles and methods of effective field theory and describe my work in three EFTs: First, in the perturbative QCD region, I use soft collinear effective theory (SCET) to prove that strong interaction soft radiation is universal and to increase the QCD accuracy to next-to-next-tonext- to leading logarithm order for new particle searches in hadron colliders. I also compute a new class of non-perturbative, large logarithmic enhancement arising near the elastic limits of deep inelastic scattering and Drell-Yan processes. Second, in the QCD confinement region, I use heavy hadron chiral perturbation theory to study near-threshold enhancements in the scattering of $D$ and $π$ mesons near the threshold for the excited $D$ -meson state, $D^{*}$ , as well as in the scattering of $D$ and $D^{*}$ mesons near the threshold for the exotic hadron X(3872). This work provides a clear picture of the hadronic molecule X(3872) and more profound understanding of the nuclear force between hadrons. Finally, inspired by SCET, I construct a new electron-laser effective field theory to describe highly-relativistic electrons traveling in strong laser fields, extract the universal distribution of electrons in strong electromagnetic backgrounds and its evolution in energy from the separated momentum scales of emitted photons and classical radiation, and predict the rate of wide angle photon emission. I conclude with limitations of EFT methods and some perspectives on what new work may be achieved with these EFTs.
↳ hep-phnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE