Nuclear Theory·nucl-th

Friday·October 13, 2017

4 papers—2 primary·2 cross-listed

01
[Submitted on 12 Oct 2017]
Rope Hadronization and Strange Particle Production
Christian Bierlich🇸🇪
Rope Hadronization is a model extending the Lund string hadronization model to describe environments with many overlapping strings, such as high multiplicity pp collisions or $AA$ collisions. Including effects of Rope Hadronization drastically improves description of strange/non-strange hadron ratios as function of event multiplicity in all systems from $e^{+} e^{-}$ to $AA$ . Implementation of Rope Hadronization in the MC event generators DIPSY and Pythia8 is discussed, as well as future prospects for jet studies and studies of small systems.
Comments:
Conference proceedings for Strangeness in Quark Matter 2017
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1710.04464 [pdf]
EPJ Web Conf.(2018)·35 citations
02
[Submitted on 12 Oct 2017]
On unitarity of the particle-hole dispersive optical model
M.L. Gorelik · S. Shlomo · B.A. Tulupov · M.H. Urin
For the recently developed particle-hole dispersive optical model, weak violations of unitarity due to a phenomenological description of the spreading effect are considered. Methods for unitarity restoration are proposed and implemented for the 208Pb nucleus in the description of the energy-averaged isoscalar monopole double transition density and strength functions in a wide excitation energy interval that includes the isoscalar giant monopole resonance and its overtone. To illustrate abilities of the model, direct neutron decay of the mentioned giant resonance is also considered.
Comments:
11 pages, 2 tables, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1710.04609 [pdf]
NPA(2018)·10 citations
03
[Submitted on 12 Oct 2017] (cross-list from hep-ph)
Features of $ω$ photoproduction off nucleon target at forward angles : Dominance of $π$ exchange with Regge cuts and scaling of differential cross sections
Byung-Geel Yu🇰🇷 · Tae Keun Choi🇰🇷 · Kook-Jin Kong🇰🇷
We investigate photoproduction of $ω$ off a nucleon target $γ N \to ω N$ by using a Reggeized model where $π (135) + σ (500) + f_{1} (1285) + f_{2} (1270)$ +Pomeron exchanges are included in the $t$ -channel for the reaction at forward angles. The reaction mechanism at low energy is featured by the dominance of the $π$ exchange with the absorptive cuts introduced to modulate the pion contribution to both $γ p \to ω p$ and $γ n \to ω n$ reactions. Necessity of $σ$ exchange is illustrated in the analysis of the cross section from natural parity exchanges. Cross sections for differential, total, and spin density matrix with beam polarization are reproduced and compared with existing data on $γ p \to ω p$ . Scaled differential cross sections of Jefferson Lab data on $γ p \to ω p$ are investigated at the production angle $θ = 9 0^{\circ}$ with the nonlinear trajectories for a saturation. Differential and total cross sections for the $γ n \to ω n$ reaction are analyzed to compare with recent experimental data at the CBELSA/TAPS Collaboration. An application to the $γ p \to ω Δ^{+}$ reaction is presented to demonstrate the significance of the $π$ exchange in the total and differential cross sections.
Comments:
11 pages, 12 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1710.04511 [pdf]
J.Phys.G(2019)·11 citations
04
[Submitted on 12 Oct 2017] (cross-list from hep-ph)
Dissecting the hadronic contributions to $(g - 2)_{μ}$ by Schwinger's sum rule
Franziska Hagelstein (JGU Mainz and AEC Bern)🇩🇪 · Vladimir Pascalutsa (JGU Mainz)🇩🇪
The theoretical uncertainty of $(g - 2)_{μ}$ is currently dominated by hadronic contributions. In order to express those in terms of directly measurable quantities, we consider a sum rule relating $g - 2$ to an integral of a photo-absorption cross section. The sum rule, attributed to Schwinger, can be viewed as a combination of two older sum rules: Gerasimov-Drell-Hearn and Burkhardt-Cottingham. The Schwinger sum rule has an important feature, distinguishing it from the other two: the relation between the anomalous magnetic moment and the integral of a photo-absorption cross section is linear, rather than quadratic. The linear property makes it suitable for a straightforward assessment of the hadronic contributions to $(g - 2)_{μ}$ . From the sum rule we rederive the Schwinger $α /2 π$ correction, as well as the formula for the hadronic vacuum-polarization contribution. As an example of the light-by-light contribution we consider the single-meson exchange.
Comments:
6 pages, 10 figures, published version extended by a few clarifying remarks and an Appendix
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1710.04571 [pdf]
PRL(2018)·30 citations

Affiliations

first authorsco-authorsvia INSPIRE

Rope Hadronization and Strange Particle Production

On unitarity of the particle-hole dispersive optical model

Features of ω photoproduction off nucleon target at forward angles : Dominance of π exchange with Regge cuts and scaling of differential cross sections

Dissecting the hadronic contributions to (g−2)μ​ by Schwinger's sum rule

Affiliations

Features of $ω$ photoproduction off nucleon target at forward angles : Dominance of $π$ exchange with Regge cuts and scaling of differential cross sections

Dissecting the hadronic contributions to $(g - 2)_{μ}$ by Schwinger's sum rule