Advanced breakup-nucleon enhancement of deuteron-induced reaction cross sections

Following the EUROfusion PPPT-programme action for an advanced modeling approach of deuteron-induced reaction cross sections, as well as specific data evaluations in addition of the TENDL files, an assessment of the details and corresponding outcome for the latter option of TALYS for the breakup model has been carried out. The breakup enhancement obtained in the meantime within computer code TALYS, by using the evaluated nucleon-induced reaction data of TENDL-2019, is particularly concerned. Discussion of the corresponding results, for deuteron-induced reactions on $$^{58}$$ 58 Ni, $$^{96}$$ 96 Zr, and $$^{231}$$ 231 Pa target nuclei up to 200 MeV incident energy, includes limitations still existing with reference to the direct-reaction account.

Forming molecular states with hadronic rescattering

A method for modelling the prompt production of molecular states using the hadronic rescattering framework of the general-purpose Pythia event generator is introduced. Production cross sections of possible exotic hadronic molecules via hadronic rescattering at the LHC are calculated for the $$\chi _{c1}(3872)$$ χ c 1 ( 3872 ) resonance, a possible tetraquark state, as well as three possible pentaquark states, $$P_c^+(4312)$$ P c + ( 4312 ) , $$P_c^+(4440)$$ P c + ( 4440 ) , and $$P_c^+(4457)$$ P c + ( 4457 ) . For the $$P_c^+$$ P c + states, the expected cross section from $$\Lambda _b$$ Λ b decays is compared to the hadronic-rescattering production. The $$\chi _{c1}(3872)$$ χ c 1 ( 3872 ) cross section is compared to the fiducial $$\chi _{c1}(3872)$$ χ c 1 ( 3872 ) cross-section measurement by LHCb and found to contribute at a level of $${\mathcal {O}({1\%})}$$ O ( 1 % ) . Finally, the expected yields of $$\mathrm {P_c^{+}}$$ P c + production from hadronic rescattering during Run 3 of LHCb are estimated. The prompt background is found to be significantly larger than the prompt $$\mathrm {P_c^{+}}$$ P c + signal from hadronic rescattering.

ADG: automated generation and evaluation of many-body diagrams

The goal of the present paper is twofold. First, a novel expansion many-body method applicable to superfluid open-shell nuclei, the so-called Bogoliubov in-medium similarity renormalization group (BIMSRG) theory, is formulated. This generalization of standard single-reference IMSRG theory for closed-shell systems parallels the recent extensions of coupled cluster, self-consistent Green’s function or many-body perturbation theory. Within the realm of IMSRG theories, BIMSRG provides an interesting alternative to the already existing multi-reference IMSRG (MR-IMSRG) method applicable to open-shell nuclei. The algebraic equations for low-order approximations, i.e., BIMSRG(1) and BIMSRG(2), can be derived manually without much difficulty. However, such a methodology becomes already impractical and error prone for the derivation of the BIMSRG(3) equations, which are eventually needed to reach high accuracy. Based on a diagrammatic formulation of BIMSRG theory, the second objective of the present paper is thus to describe the third version (v3.0) of the code that automatically (1) generates all valid BIMSRG(n) diagrams and (2) evaluates their algebraic expressions in a matter of seconds. This is achieved in such a way that equations can easily be retrieved for both the flow equation and the Magnus expansion formulations of BIMSRG. Expanding on this work, the first future objective is to numerically implement BIMSRG(2) (eventually BIMSRG(3)) equations and perform ab initio calculations of mid-mass open-shell nuclei.