Nuclear Theory·nucl-th

Wednesday·October 31, 2018

8 papers—2 primary·6 cross-listed

01
[Submitted on 29 Oct 2018]
$γ^{*} γ \to η, η^{'}$ transition form factors
Minghui Ding🇨🇳 · Khepani Raya🇨🇳 · Adnan Bashir🇲🇽 · Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · Muyang Chen🇨🇳 · Craig D. Roberts🇺🇸
Using a continuum approach to the hadron bound-state problem, we calculate $γ^{*} γ \to η, η^{'}$ transition form factors on the entire domain of spacelike momenta, for comparison with existing experiments and in anticipation of new precision data from next-generation $e^{+} e^{-}$ colliders. One novel feature is a model for the contribution to the Bethe-Salpeter kernel deriving from the non-Abelian anomaly, an element which is crucial for any computation of $η, η^{'}$ properties. The study also delivers predictions for the amplitudes that describe the light- and strange-quark distributions within the $η, η^{'}$ . Our results compare favourably with available data. Important to this at large- $Q^{2}$ is a sound understanding of QCD evolution, which has a visible impact on the $η^{'}$ in particular. Our analysis also provides some insights into the properties of $η, η^{'}$ mesons and associated observable manifestations of the non-Abelian anomaly.
Comments:
16 pages, 7 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:
1810.12313 [pdf]
PRD(2019)·83 citations
02
[Submitted on 30 Oct 2018]
Chiral soliton lattice effect on baryonic matter from skyrmion crystal model
Mamiya Kawaguchi · Yong-Liang Ma · Shinya Matsuzaki
The chiral soliton lattice (CSL) has been studied in condensed-matter system such as chiral magnets, which arises as a parity-violating topological soliton. In hadron physics, various attempts have also been made to apply the idea of CSL to baryonic matter. In this work, we explore the CSL effects on the baryonic matter based on the skrymion crystal approach. It is found that the CSL causes an inverse catalysis for the topology change in the dense baryonic matter. Furthermore, we observe that the CSL makes the single-baryon shape deformed to be highly oscillating as the frequency of the CSL gets larger, which leads to the enhancement of a baryon energy. Of interest is that in a high density region, the CSL goes away due to the topology change in the baryonic matter. What we find here might deepen our understanding of dense matter systems as well as compact stars.
Comments:
12 pages, 29 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1810.12880 [pdf]
PRC(2019)·23 citations
03
[Submitted on 30 Oct 2018] (cross-list from hep-th)
Swimming and swirling colorful ghosts
Giorgio Torrieri🇧🇷
We show that the ideal fluid limit, defined as the existance of a flow frame $u_{μ}$ with respect to which the fluid is homogeneus and isotropic, and the consequent independence of the equation of state on $u_{μ}$ , is incompatible with non-Abelian gauge theory. Instead, the equation of state becomes dependent on $u_{μ}$ via modes which are roughly equivalent to ghost modes in the hydrodynamic limit. These modes can be physically imagined as a field of 'purcell swimmers' whose 'arms and legs' are outstretched in Gauge space. Also, vorticity should couple to the Wilson loop via the chromo-electro-magnetic field tensor, which in this limit is not a 'force' but instead represents the polarization tensor of the gluons. We show that because of this coupling vorticity also aquires swirling non-hydrodynamic modes. We then argue that these swirling and swimming non-hydodynamic modes are the manifestation of gauge redunancy within local equilibrium, and speculate on their role in quark-gluon plasma thermalization
Comments:
Accepted for publication in EPJA Although the conclusions are basically the same, the argument and presentation were expanded, clarified and improved greatly
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Fluid Dynamics (physics.flu-dyn)
arXiv:
1810.12468 [pdf]
EPJA(2020)·9 citations
04
[Submitted on 30 Oct 2018] (cross-list from hep-ph)
Electrical conductivity and relaxation via colored noise in a hadronic gas
Jan Hammelmann🇩🇪 · Juan M. Torres-Rincon🇺🇸 · Jean-Bernard Rose🇩🇪 · Moritz Greif🇩🇪 · Hannah Elfner🇩🇪
Motivated by the theory of relativistic hydrodynamic fluctuations we make use of the Green-Kubo formula to compute the electrical conductivity and the (second-order) relaxation time of the electric current of an interacting hadron gas. We use the recently developed transport code SMASH to numerically solve the coupled set of Boltzmann equations implementing realistic hadronic interactions. In particular, we explore the role of the resonance lifetimes in the determination of the electrical relaxation time. As opposed to a previous calculation of the shear viscosity we observe that the presence of resonances with lifetimes of the order of the mean-free time does not appreciably affect the relaxation of the electric current fluctuations. We compare our results to other approaches describing similar systems, and provide the value of the electrical conductivity and the relaxation time for a hadron gas at temperatures between T=60 MeV and T=150 MeV.
Comments:
29 pages, 11 figures. Typos corrected, new references incorporated and minor clarifications added. Version to be published by the Physical Review D journal
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1810.12527 [pdf]
PRD(2019)·29 citations
05
[Submitted on 30 Oct 2018] (cross-list from hep-ph)
Strong Isospin Breaking in the Decay Constants of Heavy-Light Mesons from Local-Duality QCD Sum Rules
Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇦🇹 · Silvano Simula🇮🇹
We explore, by a rather peculiar limit of QCD sum rules subject to a Borel transformation (realized by allowing the related Borel mass parameter to approach infinity), how the small difference of the masses of up and down quark translates into the leptonic decay constants of pseudoscalar or vector heavy-light mesons. For the charmed and bottom mesons, we find that the decay constants of their lowest-lying charged and neutral representatives should differ by an amount of the order of 1 MeV.
Comments:
8 pages, 4 figures, talk presented at "XIII Quark Confinement and the Hadron Spectrum - Confinement2018" (31 July - 6 August 2018, Maynooth University, Ireland)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1810.12569 [pdf]
PoS(2018)·1 citation
06
[Submitted on 30 Oct 2018] (cross-list from nucl-ex)
New data on $0^{+}$ states in $^{158}$ Gd
A.I. Levon · C. Costache · T. Faestermann · R. Hertenberger · A. Ionescu · R. Lica · A.G. Magner · C. Mihai · R. Mihai · C.R. Nita · S. Pascu · K.P. Shevchenko and 3 other authors
Excited states in the deformed nucleus $^{158}$ Gd have been studied in the (p,t) reaction by using the Munich Tandem and Q3D spectrograph. 30 new excited 0 $^{+}$ states (three tentative) have been assigned up to the 4.3 MeV excitation energy. The total number of 34 excited 0 $^{+}$ states (four tentatively assigned) in a deformed nucleus, close to a complete level scheme, offers a new opportunity to test nuclear models and obtain more information on the structure of these special states.
Comments:
10 pages, 7 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1810.12592 [pdf]
PRC(2019)·8 citations
07
[Submitted on 30 Oct 2018] (cross-list from hep-lat)
Three neutrons from Lattice QCD
Jan-Lukas Wynen🇩🇪 · Evan Berkowitz🇩🇪 · Thomas Luu🇩🇪 · Andrea Shindler🇺🇸 · John Bulava🇩🇰
We present a study on ab-initio calculations of three-neutron correlators from Lattice QCD. We extend the method of baryon blocks to systems of three spacially displaced baryons. This allows the measurement of three-neutron $p$ -wave correlators with total spin $S = 1/2$ and $3/2$ . In addition, we use automatic code generation that has high flexibility and allows for easy inclusion of additional channels in the future while optimizing the evaluation of contractions. Our measurements were performed on a newly generated $96 \times 4 8^{3}$ Clover-Wilson gauge field ensemble with $m_{π} \approx 370 MeV$ . We present preliminary results of our calculations of one pion and nucleon as well as two nucleon ( $2 N$ ) and three neutron ( $3 n$ ) correlators.
Comments:
Proceedings from Lattice2018, 7 pages, 4 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1810.12747 [pdf]
PoS(2018)·3 citations
08
[Submitted on 30 Oct 2018] (cross-list from hep-ph)
Global description of bottomonium suppression in proton-nucleus and nucleus-nucleus collisions at LHC energies
Elena G. Ferreiro🇪🇸
We show that we can reach a global and coherent description of bottomonium suppression in both proton-nucleus and nucleus-nucleus collisions at the LHC energies. The measured relative suppression of the excited bottomonium states as compared to their ground state allows us to constrain the scattering cross sections between the bottomonia and the comovers created during the collisions. Our result hints at a similar energy distribution of these comovers in the environment created by proton-nucleus and nucleus-nucleus collisions. Along the way of our study, we also update our knowledge for the bottomonium feed-down pattern and our comprehension on the modification of the nuclear parton distribution functions in proton-nucleus collisions. We present our results for $p$ Pb collisions at 5.02 and 8.16 TeV and for PbPb collisions at 2.76 and 5.02 TeV.
Comments:
6 pages, 7 figures. Contribution to the Proceedings of the XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2018), 16-20 April 2018 Kobe, Japan. Based on arXiv:1804.04474
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1810.12874 [pdf]
PoS(2018)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE