Nuclear Theory·nucl-th

Tuesday·November 17, 2015

16 papers—7 primary·9 cross-listed

01
[Submitted on 13 Nov 2015]
Transport Theory of Heavy Flavor in Relativistic Nuclear Collisions
Shanshan Cao🇺🇸
A short overview is presented for the recent progress in the theory of heavy flavor transport in ultra-relativistic nuclear collisions, including a summary of different transport models, their phenomenological results of heavy meson quenching and flow at RHIC and LHC, a possible solution to the $R_{AA}$ vs. $v_{2}$ puzzle and predictions for heavy flavor observables beyond the current measurements.
Comments:
6 pages, 6 figures. A plenary talk given by Shanshan Cao at Hard Probes 2015 Conference in Montreal, Canada
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1511.04477 [pdf]
Nucl.Part.Phys.Proc.(2016)·3 citations
02
[Submitted on 14 Nov 2015]
Probing the dissipative properties of a strongly interacting medium with dileptons
Gojko Vujanovic🇨🇦 · Chun Shen🇨🇦 · Gabriel S. Denicol🇨🇦 · Bjoern Schenke🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
We investigate the effects of the presence of a non-vanishing net baryon number density and its diffusion on dilepton production, within a hydrodynamical description of the medium created at $s_{N N} = 7.7$ GeV collision energy. This energy value is explored within the Beam Energy Scan (BES) program at Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Particular attention is devoted to a new dissipative degree of freedom: the net baryon number diffusion ( $V^{μ}$ ), and to the net baryon number conductivity ( $κ$ ) | a transport coefficients governing the overall magnitude of $V^{μ}$ . The effects of $κ$ on dilepton production are assessed, with an outlook on how future experimental dilepton data can be used to learn more about $κ$ .
Comments:
Talk given at the 7th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2015), June 29-July 3 2015, Montreal, QC, Canada; 2 pages, LaTeX, 2 PDF figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1511.04625 [pdf]
PPNP(2016)·4 citations
03
[Submitted on 15 Nov 2015]
The Generalized Nuclear Contact and its Application to the Photoabsorption Cross-Section
Ronen Weiss🇮🇱 · Betzalel Bazak🇮🇱 · Nir Barnea🇮🇱
Using the zero-range model, it was demonstrated recently that Levinger's quasi-deuteron model can be utilized to extract the nuclear neutron-proton contact. Going beyond the zero-range approximation and considering the full nuclear contact formalism, we rederive here the quasi-deuteron model for the nuclear photoabsorption cross-section and utilize it to establish relations and constrains for the general contact matrix. We also define and demonstrate the importance of the diagonalized nuclear contacts, which can be also relevant to further applications of the nuclear contacts.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1511.04722 [pdf]
EPJA(2016)·21 citations
04
[Submitted on 15 Nov 2015]
Recent developments in neutron-proton scattering with Lattice Effective Field Theory
Jose Manuel Alarcón🇩🇪
In this contribution, we show some recent progress in the study of neutron-proton scattering with Nuclear Lattice Effective Field Theory (NLEFT). We present preliminary studies of both, the uncertainties in the $n p$ phase shifts extracted with NLEFT, and the lattice spacing dependence in the transfer matrix formalism. Such investigations have not been performed before in the literature, and will be relevant for Monte Carlo simulations of nuclear structure with NLEFT.
Comments:
Contribution to the Workshop "Chiral Dynamics 2015", Pisa, Italy, June 29 to July 3, 2015. 8 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1511.04744 [pdf]
PoS(2016)·0 citations
05
[Submitted on 16 Nov 2015]
The specific charged hadron multiplicity in ep and eD semi-inclusive deep-inelastic scattering in the PYTHIA and PACIAE models
Yu-Liang Yan🇨🇳 · Xing-Long Li🇨🇳 · Xiao-Mei Li🇨🇳 · Dai-Mei Zhou🇨🇳 · Yun Cheng🇨🇳 · Bao-Guo Dong🇨🇳 · Xu Cai🇨🇳 · Ben-Hao Sa🇨🇳
We employed the PYTHIA 6.4 model and the extended parton and hadron cascade model PACIAE 2.2 to comparatively investigate the DIS normalized specific charged hadron multiplicity in the 27.6 GeV electron semi-inclusive deep-inelastic scattering off proton and deuteron. The PYTHIA and PACIAE results calculated with default model parameters not well and fairly well reproduce the corresponding HERMES data, respectively. In addition, we have discussed the effects of the differences between the PYTHIA and PACIAE models.
Comments:
8 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1412.7579
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1511.04844 [pdf]
0 citations
06
[Submitted on 16 Nov 2015]
Enhanced effects of the Lorentz invariance and Einstein equivalence principle violation in 229Th nuclear transition
V.V. Flambaum🇦🇺
The Lorentz invariance and Einstein equivalence principle violating effects in the narrow 7.8 eV transition in 229Th nucleus may be 100 000 times larger than in atoms. This transition may be investigated using high precision laser spectroscopy methods, has a very small width, and suppressed systematic effects. Similar values of the effects are expected in 73 eV 235U nuclear transition which is coming within the reach of the laser spectroscopy. Mossbauer transitions give another possibility.
Subjects:
Nuclear Theory (nucl-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Atomic Physics (physics.atom-ph)
arXiv:
1511.04848 [pdf]
1 citation
07
[Submitted on 16 Nov 2015]
Leading-twist parton distribution amplitudes of S-wave heavy-quarkonia
Minghui Ding🇨🇳 · Fei Gao🇨🇳 · Lei Chang🇨🇳 · Yu-Xin Liu🇨🇳 · Craig D. Roberts🇺🇸
The leading-twist parton distribution amplitudes (PDAs) of ground-state $^{1} S_{0}$ and $^{3} S_{1}$ $c c ˉ$ - and $b b ˉ$ -quarkonia are calculated using a symmetry-preserving continuum treatment of the meson bound-state problem which unifies the properties of these heavy-quark systems with those of light-quark bound-states, including QCD's Goldstone modes. Analysing the evolution of $^{1} S_{0}$ and $^{3} S_{1}$ PDAs with current-quark mass, $m^_{q}$ , increasing away from the chiral limit, it is found that in all cases there is a value of $m^_{q}$ for which the PDA matches the asymptotic form appropriate to QCD's conformal limit and hence is insensitive to changes in renormalisation scale, $ζ$ . This mass lies just above that associated with the $s$ -quark. At current-quark masses associated with heavy-quarkonia, on the other hand, the PDAs are piecewise convex-concave-convex. They are much narrower than the asymptotic distribution on a large domain of $ζ$ ; but nonetheless deviate noticeably from $φ_{Q Q ˉ} (x) = δ (x - 1/2)$ , which is the result in the static-quark limit. There are also material differences between $^{1} S_{0}$ and $^{3} S_{1}$ PDAs, and between the PDAs for different vector-meson polarisations, which vanish slowly with increasing $ζ$ . An analysis of moments of the root-mean-square relative-velocity, $⟨ v^{2 m} ⟩$ , in $^{1} S_{0}$ and $^{3} S_{1}$ systems reveals that $⟨ v^{4} ⟩$ -contributions may be needed in order to obtain a reliable estimate of matrix elements using such an expansion, especially for processes involving heavy pseudoscalar quarkonia.
Comments:
6 pages, 2 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1511.04943 [pdf]
PLB(2016)·77 citations
08
[Submitted on 14 Nov 2015] (cross-list from hep-ph)
D meson mass increase by restoration of chiral symmetry in nuclear matter
Kei Suzuki🇯🇵 · Philipp Gubler🇮🇹 · Makoto Oka🇯🇵
Spectral functions of the pseudoscalar $D$ meson in the nuclear medium are analyzed using QCD sum rules and the maximum entropy method. This approach enables us to extract the spectral functions without any phenomenological assumption, and thus to visualize in-medium modification of the spectral functions directly. It is found that the reduction of the chiral condensates of dimension 3 and 5 causes the masses of both $D^{+}$ and $D^{-}$ mesons to grow gradually at finite density. Additionally, we construct charge-conjugate-projected sum rules and find a $D^{+}$ - $D^{-}$ mass splitting of about -15 MeV at nuclear saturation density.
Comments:
12 pages, 7 figures; published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1511.04513 [pdf]
PRC(2016)·55 citations
09
[Submitted on 14 Nov 2015] (cross-list from hep-lat)
Nucleon axial and tensor charges with dynamical overlap quarks
N. Yamanaka🇯🇵 · H. Ohki🇺🇸 · S. Hashimoto🇯🇵 · T. Kaneko🇯🇵
We report on our calculation of the nucleon axial and tensor charges in 2+1-flavor QCD with dynamical overlap quarks. Gauge ensembles are generated at a single lattice spacing 0.12 fm and at a strange quark mass close to its physical value. We employ the all-mode-averaging technique to calculate the relevant nucleon correlation functions, and the disconnected quark loop is efficiently calculated by using the all-to-all quark propagator. We present our preliminary results for the isoscalar and isovector charges obtained at pion masses $m_{π}$ = 450 and 540 MeV.
Comments:
7 pages, 10 figures, proceeding of the 33rd International Symposium on Lattice field theory (Lattice 2015), Kobe, Japan, July 2015
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1511.04589 [pdf]
PoS(2016)·11 citations
10
[Submitted on 15 Nov 2015] (cross-list from cond-mat.quant-gas)
Mesoscopic dynamics of fermionic cold atoms ---Quantitative analysis of transport coefficients and relaxation times---
Yuta Kikuchi · Kyosuke Tsumura · Teiji Kunihiro
We give a quantitative analysis of the dynamical properties of fermionic cold atomic gases in normal phase, such as the shear viscosity, heat conductivity, and viscous relaxation times, using the novel microscopic expressions derived by the renormalization group (RG) method, where the Boltzmann equation is faithfully solved to extract the hydrodynamics without recourse to any ansatz. In particular, we examine the quantum statistical effects, temperature dependence, and scattering-length dependence of the transport coefficients and the viscous relaxation times. The numerical calculation shows that the relation $τ_{π} = η / P$ , which is derived in the relaxation-time approximation (RTA) and is used in most of the literature, turns out to be satisfied quite well, while the similar relation for the viscous relaxation time $τ_{J}$ of the heat conductivity is satisfied only approximately with a considerable error.
Comments:
20 pages, 6 figures, version accepted for publication in Physics Letters A
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
1511.04675 [pdf]
PLA(2016)·16 citations
11
[Submitted on 16 Nov 2015] (cross-list from hep-ph)
Strong decay patterns of the hidden-charm pentaquark states $P_{c} (4380)$ and $P_{c} (4450)$
Guang-Juan Wang🇨🇳 · Li Ma🇨🇳 · Xiang Liu🇨🇳 · Shi-Lin Zhu🇨🇳
With the heavy quark symmetry and spin rearrangement scheme, we study the strong decay behavior of the hidden-charm pentaquark states with $J^{P} = \frac{3}{2}^{\pm}, \frac{5}{2}^{\pm}$ assuming they are molecular candidates composed of $D ˉ^{(*)}$ and $Σ_{c}^{(*)}$ . We obtain several typical ratios of the partial decay widths of the hidden-charm pentaquarks. For the three S-wave $(D ˉ Σ_{c}^{*})$ , $(D ˉ^{*} Σ_{c})$ and $(D ˉ^{*} Σ_{c}^{*})$ molecular pentaquarks with $J^{P} = 3 / 2^{-}$ , we have obtained the ratio of their $J / ψ N$ decay widths: $Γ [(D ˉ Σ_{c}^{*})] : Γ [(D ˉ^{*} Σ_{c})] : Γ [(D ˉ^{*} Σ_{c}^{*})] = 2.7 : 1.0 : 5.4$ , which may be useful to further test the possible molecular assignment of the $P_{c}$ states.
Comments:
9 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1511.04845 [pdf]
PRD(2016)·32 citations
12
[Submitted on 16 Nov 2015] (cross-list from hep-lat)
Nuclear physics from QCD on lattice
Takashi Inoue · for HAL QCD Collaboration
We have presented a strategy to study nuclei and nuclear matters from first principles, namely, from QCD. We first compute nucleon-nucleon potentials numerically in lattice QCD, and then use them to investigate properties of nuclei and nuclear matter by various methods developed in nuclear physics. As a demonstration that this strategy works, mass and structure of ^4^He, ^16^O and ^40^Ca, and equation of state of nuclear matters are determined with the lattice QCD induced two-nucleon potentials in a heavy quark region as an input. We have found that these nuclei and the symmetric nuclear matter are bound at one quark mass corresponding to the pseudo-scalar meson (pion) mass of 469 MeV (the octet baryon (nucleon) mass of 1161 MeV). The obtained binding energy per nucleon has a uniform mass-number A dependence which is consistent to the Bethe-Weizsacker mass formula qualitatively. The present study demonstrates that our strategy works well to investigate various properties of atomic nuclei and nuclear matter starting from QCD, without depending on models or experimental information about the nuclear force.
Comments:
Typos are corrected, 20 pages, 15 figures, proceedings of the 8th International Workshop on Chiral Dynamics, 29 June - 3 July 2015, Pisa, Italy
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1511.04871 [pdf]
PoS(2016)·6 citations
13
[Submitted on 16 Nov 2015] (cross-list from hep-ph)
Decay $B \to K^{*} (\to K π) ℓ^{+} ℓ^{-}$ in covariant quark model
Stanislav Dubnička🇸🇰 · Anna Z. Dubničková🇸🇰 · Nurgul Habyl🇰🇿 · Mikhail A. Ivanov🇷🇺 · Andrej Liptaj🇸🇰 · Guliya S. Nurbakova🇰🇿
Our article is devoted to the study of the rare $B \to K^{*} ℓ^{+} ℓ^{-}$ ~decay where $ℓ = e, μ, τ$ . We compute the relevant form factors in the framework of the covariant quark model with infrared confinement in the full kinematical momentum transfer region. The calculated form factors are used to evaluate branching fractions and polarization observables in the cascade decay $B \to K^{*} (\to K π) ℓ^{+} ℓ^{-}$ . We compare the obtained results with available experimental data and the results from other theoretical approaches.
Comments:
39 pages, 11 figures. References and discussion added. Accepted by Few-Body Systems for publication. arXiv admin note: text overlap with arXiv:hep-ph/0608015 by other authors
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1511.04887 [pdf]
Few Body Syst.(2016)·15 citations
14
[Submitted on 16 Nov 2015] (cross-list from cond-mat.quant-gas)
Current algebra for a generalized two-site Bose-Hubbard model
Gilberto N. Santos Filho
We present a current algebra for a generalized two-site Bose-Hubbard model and use it to get the quantum dynamics of the currents. For different choices of the Hamiltonian parameters we get different currents dynamics. We generalize the Heisenberg equation of motion to write the n-th time derivative of any operator.
Comments:
5 pages, 3 figures. arXiv admin note: text overlap with arXiv:1505.06793
Subjects:
Quantum Gases (cond-mat.quant-gas); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Superconductivity (cond-mat.supr-con); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
1511.05026 [pdf]
2 citations
15
[Submitted on 16 Nov 2015] (cross-list from hep-ph)
A Three-Flavor Chiral Effective Model with Four Baryonic Multiplets within the Mirror Assignment
Lisa Olbrich🇩🇪 · Miklós Zétényi🇩🇪 · Francesco Giacosa🇩🇪 · Dirk H. Rischke🇩🇪
In the case of three quark flavors, (pseudo)scalar diquarks transform as antiquarks under chiral transformations. We construct four spin-1/2 baryonic multiplets from left- and right-handed quarks as well as left- and right-handed diquarks. The fact that two of these multiplets transform in a "mirror" way allows for chirally invariant mass terms. We then embed these baryonic multiplets into the Lagrangian of the so-called extended Linear Sigma Model, which features (pseudo)scalar and (axial-)vector mesons, as well as glueballs. Reducing the Lagrangian to the two-flavor case, we obtain four doublets of nucleonic states. These mix to produce four experimentally observed states with definite parity: the positive-parity nucleon $N (939)$ and Roper resonance $N (1440)$ , as well as the negative-parity resonances $N (1535)$ and $N (1650)$ . We determine the parameters of the nucleonic part of the Lagrangian from a fit to masses and decay properties of the aforementioned states. Studying the limit of vanishing quark condensate, we conclude that $N (939)$ and $N (1535)$ , as well as $N (1440)$ and $N (1650)$ form pairs of chiral partners.
Comments:
19 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1511.05035 [pdf]
PRD(2016)·37 citations
16
[Submitted on 16 Nov 2015] (cross-list from cond-mat.quant-gas)
Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases
Alexander Galea · Hillary Dawkins · Stefano Gandolfi · Alexandros Gezerlis
Ultracold atomic Fermi gases have been a popular topic of research, with attention being paid recently to two-dimensional (2D) gases. In this work, we perform T=0 ab initio diffusion Monte Carlo calculations for a strongly interacting two-component Fermi gas confined to two dimensions. We first go over finite-size systems and the connection to the thermodynamic limit. After that, we illustrate pertinent 2D scattering physics and properties of the wave function. We then show energy results for the strong-coupling crossover, in between the Bose-Einstein Condensation (BEC) and Bardeen-Cooper-Schrieffer (BCS) regimes. Our energy results for the BEC-BCS crossover are parametrized to produce an equation of state, which is used to determine Tan's contact. We carry out a detailed comparison with other microscopic results. Finally, we calculate the pairing gap for a range of interaction strengths in the strong coupling regime, following from variationally optimized many-body wave functions.
Comments:
10 pages, 9 figures; v2 corresponds to the published version
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
arXiv:
1511.05123 [pdf]
PRA(2016)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE