Nuclear Theory·nucl-th

Tuesday·November 1, 2016

26 papers—16 primary·10 cross-listed

17
[Submitted on 29 Oct 2016] (cross-list from hep-lat)
Thermal dynamics on the lattice with exponentially improved accuracy
Jan Pawlowski🇩🇪 · Alexander Rothkopf🇩🇪
We present a novel simulation prescription for thermal quantum fields on a lattice that operates directly in imaginary frequency space. By distinguishing initial conditions from quantum dynamics it provides access to correlation functions also outside of the conventional Matsubara frequencies $ω_{n} = 2 π n T$ . In particular it resolves their frequency dependence between $ω = 0$ and $ω_{1} = 2 π T$ , where the thermal physics $ω \sim T$ of e.g.~transport phenomena is dominantly encoded. Real-time spectral functions are related to these correlators via an integral transform with rational kernel, so their unfolding is exponentially improved compared to Euclidean simulations. We demonstrate this improvement within a $0 + 1$ -dimensional scalar field theory and show that spectral features inaccessible in standard Euclidean simulations are quantitatively captured.
Comments:
5 pages, 4 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1610.09531 [pdf]
PLB(2018)·14 citations
18
[Submitted on 30 Oct 2016] (cross-list from hep-ph)
Puzzle of the $Λ_{c}$ spectrum
Qi-Fang Lü🇨🇳 · Yubing Dong🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵
There is a puzzle in the $Λ_{c}^{+}$ family, i.e., one member with $J^{P} = 3/ 2^{+}$ is missing in a $L = 2$ multiplet which the heavy quark effective theory predicts, and $J^{P}$ 's of $Λ_{c} (2765)^{+}$ and $Λ_{c} (2940)^{+}$ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two $Λ_{c}$ 's with unknown $J^{P}$ and the missing $Λ_{c}^{+}$ with $3/ 2^{+}$ for $L = 2$ , and we find the most probable possibility that the peak corresponding to $Λ_{c} (2880)^{+}$ actually includes a missing member with spin $3/ 2^{+}$ for $L = 2$ and that quantum numbers of $Λ_{c} (2765)^{+}$ and $Λ_{c} (2940)^{+}$ are $2 S (1/ 2^{+})$ and $2 P (1/ 2^{-})$ , respectively.
Comments:
3 pages, 3 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1610.09605 [pdf]
Nucl.Phys.Rev.(2018)·28 citations
19
[Submitted on 30 Oct 2016] (cross-list from hep-ph)
Legendre Analysis of Hadronic Reactions
Ya.I. Azimov🇷🇺
Expansions over Legendre functions are suggested as a model-independent way of compact presentation of modern precise and high-statistics data for two-hadron reactions. Some properties of the expansions are described.
Comments:
Talk at the Conference "Hadron Structure and Quantum Chromodynamics" (HSQCD2016), Gatchina, 27 June - 1 July, 2016. To appear in the Proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1610.09677 [pdf]
1 citation
20
[Submitted on 31 Oct 2016] (cross-list from hep-lat)
Lüscher's finite volume test for two-baryon systems with attractive interactions
Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Takumi Iritani🇺🇸
For the attractive interaction, the Lüscher's finite volume formula gives the phase shift at negative squared moment $k^{2} < 0$ for the ground state in the finite volume, which corresponds to the analytic continuation of the phase shift at $k^{2} < 0$ in the infinite volume. Using this fact, we reexamine behaviors of phase shifts at $k^{2} < 0$ obtained directly from plateaux of effective energy shifts in previous lattice studies for two nucleon systems on various volumes. We have found that data, based on which existences of the bound states are claimed, show singular behaviors of the phase shift at $k^{2} < 0$ , which seem incompatible with smooth behaviors predicted by the effective range expansion. This, together with the fake plateau problem for the determination of the energy shift, brings a serious doubt on existences of the $N N$ bound states claimed in previous lattice studies at pion masses heavier than 300 MeV.
Comments:
7 pages, 16 figures, Talk presented at 34th annual International Symposium on Lattice Field Theory, 24-30 July 2016, University of Southampton, UK. A few typos are corrected. The published version
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1610.09763 [pdf]
PoS(2016)·9 citations
21
[Submitted on 31 Oct 2016] (cross-list from hep-th)
Strongly coupled $N = 4$ super Yang-Mills plasma on the Coulomb branch I: Thermodynamics
Kiminad A. Mamo🇺🇸
We study $N = 4$ super Yang-Mills theory on the Coulomb branch (cSYM) in the strong coupling limit by using the AdS/CFT correspondence. The dual geometry is the rotating black 3-brane Type IIB supergravity solution with a single non-zero rotation parameter $r_{0}$ which sets a fixed mass scale corresponding to the scalar condensate $< O > \sim r_{0}^{4}$ in the Coulomb branch. We introduce a new ensemble where $T$ and $< O >$ are held fixed, i.e., the free energy $F (T, < O >)$ is a function of $T$ and $< O >$ . We compute the equation of state (EoS) of $N = 4$ cSYM at finite $T$ , as well as the heavy quark-antiquark potential and the quantized mass spectrums of the scalar and spin-2 glueballs at $T = 0$ . By computing the Wilson loop (minimal surface) at $T = 0$ , we determine the heavy quark-antiquark potential $V (L)$ to be the Cornell potential, which is confining for large separation $L$ . At $T \neq = 0$ , we find two black hole branches: the large black hole and small black hole branches. For the large black hole branch, that has positive specific heat, we find qualitatively similar EoS to that of pure Yang-Mills theory on the lattice. For the small black hole branch, that has negative specific heat, we find an EoS where the entropy and energy densities decrease with $T$ . We also find a second-order phase transition between the large and small black hole branches with critical temperature $T_{c} = T_{min}$ .
Comments:
7 pages, 7 figures; the discussion and conjecture about hadronization is removed and will be addressed elsewhere with a proof
Subjects:
High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1610.09792 [pdf]
PRD(2019)·5 citations
22
[Submitted on 31 Oct 2016] (cross-list from hep-th)
Strongly coupled $N = 4$ super Yang-Mills plasma on the Coulomb branch II: Transport coefficients and hard probe parameters
Kiminad A. Mamo🇺🇸
We study $N = 4$ super Yang-Mills theory on the Coulomb branch (cSYM) by using its Type IIB supergravity dual. We compute the transport coefficients, and hard probe parameters of $N = 4$ cSYM at finite temperature $T$ . We use the rotating black 3-brane solution of Type IIB supergravity with a single non-zero rotation parameter $r_{0}$ after analytically continuing $r_{0} \to - i r_{0}$ , and in an ensemble where the Hawking temperature $T$ and a scalar condensate $< O >\sim r_{0}^{4}$ are held fixed. We find that the bulk viscosity to entropy density ratio of the large black hole branch decreases with temperature and has a maxima around the critical temperature $T_{c}$ while, for the small black hole branch, it increases with temperature. The other transport coefficients and parameters of hard probes, such as the conductivity, jet quenching parameter, drag force, and momentum diffusion coefficients of the large black hole branch increase with temperature and asymptote to their conformal value while, for the small black hole branch, they decrease with temperature.
Comments:
7 pages, 6 figures; title changed
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1610.09793 [pdf]
PRD(2019)·6 citations
23
[Submitted on 31 Oct 2016] (cross-list from hep-ph)
Delayed versus accelerated quarkonium formation in a magnetic field
Kei Suzuki🇰🇷 · Su Houng Lee🇰🇷
Formation time of heavy quarkonia in a homogeneous magnetic field is analyzed by using a phenomenological ansatz of the vector current correlator. Because the existence of a magnetic field mixes vector quarkonia ( $J / ψ$ , $ψ^{'}$ ) and their pseudoscalar partners ( $η_{c}$ , $η_{c}^{'}$ ), the properties of the quarkonia can be modified through such a spin mixing. This means that the formation time of quarkonia is also changed by the magnetic field. We show the formation time of vector quarkonia is delayed by an idealized constant magnetic field, where the formation time of the excited state becomes longer than that of the ground state. As a more realistic situation in heavy-ion collisions, effects by a time-dependent magnetic field are also discussed, where delayed formation of $J / ψ$ and $ψ^{'}$ and very early formation of $η_{c}$ and $η_{c}^{'}$ are found.
Comments:
7 pages, 4 figures; published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1610.09853 [pdf]
PRC(2017)·31 citations
24
[Submitted on 31 Oct 2016] (cross-list from hep-ph)
Nuclear and Quark Matter at High Temperature
T.S.Biro🇭🇺 · A.Jakovac🇭🇺 · Z.Schram🇭🇺
We review important ideas on nuclear and quark matter description on the basis of high- temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the - partially still open - problems of the hadronization process.
Comments:
Review intended for EPJ A Topical Issue
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1610.09973 [pdf]
EPJA(2017)·7 citations
25
[Submitted on 31 Oct 2016] (cross-list from hep-ph)
Holographic QCD predictions for production and decay of pseudoscalar glueballs
Frederic Brünner🇦🇹 · Anton Rebhan🇦🇹
The top-down holographic Witten-Sakai-Sugimoto model for low-energy QCD, augmented by finite quark masses, has recently been found to be able to reproduce the decay pattern of the scalar glueball candidate f0(1710) on a quantitative level. In this Letter we show that this model predicts a narrow pseudoscalar glueball heavier than the scalar glueball and with a very restricted decay pattern involving eta or eta' mesons. Production should be either in pairs or in association with eta(') mesons. We discuss the prospect of discovery in high-energy hadron collider experiments through central exclusive production by comparing with eta' pair production.
Comments:
9 pages, 4 figures. v3: sync with proof-read version to appear in PLB
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1610.10034 [pdf]
PLB(2017)·24 citations
26
[Submitted on 31 Oct 2016] (cross-list from hep-lat)
Chiral Extrapolation of the Sigma Resonance
Michael Döring🇺🇸 · Bin Hu🇺🇸 · Maxim Mai🇺🇸
We analyze recent results on isoscalar $π π$ scattering from a $N_{f} = 2 + 1$ lattice simulation by the HadronSpectrum collaboration by re-summing the two-flavor chiral scattering amplitude of the next-to-leading order in the so-called inverse amplitude method. The lattice data can be well extrapolated to the physical pion mass. We also find that both $I = 0$ and $I = 1$ lattice data can be described simultaneously for pion masses up to $M_{π} = 236$ MeV.
Comments:
11 pages, 14 figures, 2 tables
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1610.10070 [pdf]
PLB(2018)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE