Nuclear Theory·nucl-th

Monday·May 2, 2022

7 papers—3 primary·4 cross-listed

04
Nucleon and $Δ$ resonances in $γ n \to K^{+} Σ^{-}$ photoproduction
Neng-Chang Wei🇨🇳 · Ai-Chao Wang🇨🇳 · Fei Huang🇨🇳 · Kanzo Nakayama🇺🇸
The most recent data on beam asymmetries, $Σ$ , and beam-target asymmetries, $E$ , from the CLAS Collaboration, together with the previous data on differential cross sections and beam asymmetries from the CLAS and LEPS Collaborations, for the $γ n \to K^{+} Σ^{-}$ reaction are studied based on an effective Lagrangian approach in the tree-level Born approximation. The $t$ -channel $K$ and $K^{*} (892)$ exchanges, the $u$ -channel $Σ$ exchange, the interaction current, and the exchanges of $N$ , $Δ$ , and their excited states in the $s$ channel are considered in constructing the reaction amplitudes to describe the available experimental data. The reaction mechanisms of $γ n \to K^{+} Σ^{-}$ are analyzed, and the associated resonances' parameters are extracted. The numerical results show that the $Δ$ exchange and the $N (1710) 1/ 2^{+}$ , $N (1880) 1/ 2^{+}$ , $N (1900) 3/ 2^{+}$ , and $Δ (1920) 3/ 2^{+}$ resonance exchanges in the $s$ -channel dominate the $γ n \to K^{+} Σ^{-}$ reaction in the lower energy region, and the $t$ -channel $K^{*} (892)$ exchange plays a crucial role at forward angles in the higher energy region.
↳ hep-phnucl-thPRD(2022)·14 citations
05
Complete calculation of exclusive heavy vector meson production at next-to-leading order in the dipole picture
Heikki Mäntysaari🇫🇮 · Jani Penttala🇫🇮
Exclusive production of transversely polarized heavy vector mesons in deep inelastic scattering at high energy is calculated at next-to-leading order accuracy in the Color Glass Condensate framework. In addition to the first QCD correction proportional to the strong coupling constant $α_{s}$ , we systematically also include the first relativistic correction proportional to the heavy quark velocity squared $v^{2}$ . When combined with our previously published results for longitudinal vector meson production at next-to-leading order accuracy, these results make phenomenological calculations of heavy vector meson production possible at the order $O (α_{s} v^{0}, α_{s}^{0} v^{2})$ . When applied to $J / ψ$ and $Υ$ production at HERA and at the LHC, a good agreement between the next-to-leading order calculations and experimental data is found. Additionally, we demonstrate that vector meson production can provide additional constraints compared to structure function analyses when the nonperturbative initial condition for the Balitsky-Kovchegov evolution equation is extracted.
↳ hep-phnucl-thJHEP(2022)·84 citations
06
Dynamic Magnetic Response of Quark-Gluon Plasma to Electromagnetic Fields
Christopher Grayson🇺🇸 · Martin Formanek🇺🇸 · Johann Rafelski🇺🇸 · Berndt Mueller🇺🇸
We investigate the electromagnetic response of a viscous quark-gluon plasma in the framework of the relativistic Boltzmann equation with current conserving collision term. Our formalism incorporates dissipative effects at all orders in linear response to the electromagnetic field while accounting for the full space- and time-dependence of the perturbing fields. As an example, we consider the collision of two nuclei in a stationary, homogeneous quark-gluon plasma. We show that for large collision energies the induced magnetic fields are governed by the response of quark-gluon plasma along the light-cone. In this limit we derive an analytic expression for the magnetic field along the beam axis between the receding nuclei and show that its strength varies only weakly with collision energy for $s_{NN} \geq 30$ GeV.
↳ hep-phnucl-thPRD(2022)·19 citations
07
The fast neutron induced fission of $^{240}$ Pu and $^{242}$ Pu
A. Pica · A.T.Chemey · W. Loveland
We report the measurement of the TKE release in the fast neutron induced fission of $^{240}$ Pu and $^{242}$ Pu. The results are compared to the predictions of the GEF model, the CGMF model, and the model of Denisov and Sedykh as well as previous experimental work on these reactions. Our absolute measurements of the TKE release are in good agreement with the previous measurements of Nethaway \textit{et al.} for the interaction of 14.8 MeV neutrons with $^{240}$ Pu \cite{Nethaway} and of Winkelmann and Aumann for the interaction of 15 MeV neutrons with $^{242}$ Pu \cite{Winkelmann}. The general trends of the measured TKE values agree with phenomenological models but the variances of the TKE distributions are significantly less than predicted by various models. The mean post neutron emission TKE release decreases non- linearly with increasing neutron energy and can be represented as TKE(MeV) = 175.8 $\pm$ 0.3 - (2. 4 $\pm$ 0.8)log $_{10}$ E $_{n}$ - (1.4 $\pm$ 0.4)log $_{10}$ E $_{n}^{2}$ for $^{240}$ Pu and TKE(MeV) = 177.1 $\pm$ 0.3 - (1.2 $\pm$ 0.9)log $_{10}$ E $_{n}$ - (1.8 $\pm$ 0.5)log $_{10}$ E $_{n}^{2}$ for $^{242}$ Pu.
↳ nucl-exnucl-thPRC(2022)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Nucleon and Δ resonances in γn→K+Σ− photoproduction

Complete calculation of exclusive heavy vector meson production at next-to-leading order in the dipole picture

Dynamic Magnetic Response of Quark-Gluon Plasma to Electromagnetic Fields

The fast neutron induced fission of 240Pu and 242Pu

Affiliations

Nucleon and $Δ$ resonances in $γ n \to K^{+} Σ^{-}$ photoproduction

The fast neutron induced fission of $^{240}$ Pu and $^{242}$ Pu