Nuclear Theory·nucl-th

Thursday·December 7, 2017

8 papers—6 primary·2 cross-listed

07
[Submitted on 6 Dec 2017] (cross-list from hep-ph)
Spectral Functions from the Functional Renormalization Group
Jochen Wambach🇮🇹 · Christopher Jung🇩🇪 · Fabian Rennecke🇺🇸 · Ralf-Arno Tripolt🇩🇪 · Lorenz von Smekal🇩🇪
We present results for in-medium spectral functions obtained within the Functional Renormalization Group framework. The analytic continuation from imaginary to real time is performed in a well-defined way on the level of the flow equations. Based on this recently developed method, results for the sigma and the pion spectral function for the quark-meson model are shown at finite temperature, finite quark-chemical potential and finite spatial momentum. It is shown how these spectral function become degenreate at high temperatures due to the restoration of chiral symmetry. In addition, results for vector- and axial-vector meson spectral functions are shown using a gauged linear sigma model with quarks. The degeneration of the $ρ$ and the $a_{1}$ spectral function as well as the behavior of their pole masses is discussed.
Comments:
CPOD 2017 Proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1712.02093 [pdf]
PoS(2018)·2 citations
08
[Submitted on 6 Dec 2017] (cross-list from hep-ph)
Amplitude analysis of the anomalous decay $η^{'} \to π^{+} π^{-} γ$
Ling-Yun Dai🇨🇳 · Xian-Wei Kang🇹🇼 · Ulf-G. Meißner🇩🇪 · Xin-Ying Song🇩🇪 · De-Liang Yao🇪🇸
In this paper we perform an amplitude analysis of $η^{'} \to π^{+} π^{-} γ$ and confront it with the latest BESIII data. Based on the final-state interaction theorem, we represent the amplitude in terms of an Omnés function multiplied by a form factor that corresponds to the contributions from left-hand cuts and right-hand cuts in the inelastic channels. We also take into account the isospin violation effect induced by $ρ - ω$ mixing. Our results show that the anomaly contribution is mandatory in order to explain the data. Its contribution to the decay width of $Γ (η^{'} \to π π γ)$ is larger than that induced by isospin violation. Finally we extract the pole positions of the $ρ$ and $ω$ as well as their corresponding residues.
Comments:
12 pages, 5 figures, typos corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.02119 [pdf]
PRD(2018)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE

Spectral Functions from the Functional Renormalization Group

Amplitude analysis of the anomalous decay η′→π+π−γ

Affiliations

Amplitude analysis of the anomalous decay $η^{'} \to π^{+} π^{-} γ$