Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1409.3023

Strongly Intensive Measures for Particle Number Fluctuations: Effects of Hadronic Resonances

Viktor V. Begun·Mark I. Gorenstein·Katarzyna Grebieszkow
View original source ↗Read source document ↗Export metadata ↓

Abstract

Strongly intensive measures $Δ$ and $Σ$ are used to study event-by-event fluctuations of hadron multiplicities in nucleus-nucleus collisions. The effects of resonance decays are investigated within statistical model and relativistic transport model. Two specific examples are considered: resonance decays to two positively charged particles (e.g., $Δ^{++}\rightarrow p+ π^+$) and to $π^+π^-$-pairs. (e.g., $ρ^0\rightarrow π^-+π^+$). It is shown that resonance abundances at the chemical freeze-out can be estimated by measuring the fluctuations of the number of stable hadrons. These model results are compared to the full hadron-resonance gas analysis within both the grand canonical and canonical ensemble. The ultra-relativistic quantum molecular dynamics (UrQMD) model of nucleus-nucleus collisions is used to illustrate the role of global charge conservation, centrality selection, and limited experimental acceptance.

Explore related subjects

nucl-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Viktor V. Begun, Mark I. Gorenstein, Katarzyna Grebieszkow. 2015-05-15. Strongly Intensive Measures for Particle Number Fluctuations: Effects of Hadronic Resonances. https://doi.org/10.1088/0954-3899%2F42%2F7%2F075101

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Interpretable hybrid nuclear mass prediction based on term-by-term model discrepancies

Various theoretical mass models have consistently achieved impressive accuracy in reproducing experimental masses. However, their predictions in unmeasured neutron-rich regions exhibit noticeable model dependence. In this study, we systematically investigate the differences in model predictions by comparing the liquid-drop mass terms of two representative models. Using two widely used models, Weizsacker-Skyrme-type (WS4) and Duflo-Zuker-type (DZ10), as representative examples, we find that the differences in an isotope chain gradually become more remarkable with increasing neutron number, not only for total binding energies but also for individual mass terms. The most noticeable difference appears in the volume-symmetry energy. By leveraging the term-by-term differences between the liquid-drop energy components of WS4 and DZ10, we introduce a machine learning gating network that adaptively combines the two models to improve predictive accuracy. This conditional hybrid model achieves a lower root-mean-square deviation (rmsd) than either model alone, reducing the overall rmsd from 0.284 MeV (WS4) and 0.560 MeV (DZ10) to 0.232 MeV. In the future, this term-by-term comparison strategy can be extended to models based on density-functional theories.

nucl-th↗
arXiv2026

Enhanced hydrodynamic predictions for $v_{02}(p_T)$

We present hydrodynamic predictions for the new observable $v_{02}(p_T)$, which measures the correlation of particle spectra with elliptic flow. We implement a data-driven correction so as to match hydrodynamic calculations to elliptic flow ($v_2(p_T)$) data. The corrected results are in fair agreement with $v_0(p_T)$ data up to high $p_T$. We make predictions for $v_{02}(p_T)$ of unidentified charged hadrons up to $p_T=10$~GeV$/c$, and of pions, kaons and protons up to $p_T=5-6$~GeV$/c$, in several centrality windows, for Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$~TeV. We predict a decrease of $v_{02}(p_T)$ of charged hadrons for $p_T>4$~GeV$/c$ and meson-baryon splitting for $p_T>3$~GeV$/c$ in mid-central collisions. We also predict a non-monotonic variation of $v_{02}(p_T)$ for protons at low $p_T$ above $30\%$ centrality. This is a specific feature of this new observable, which is not observed for the usual flow observables $v_2(p_T)$ and $v_0(p_T)$.

nucl-th↗
arXiv2026

Gaussian characterization of two-neutron halo nuclei

The halo nucleon-core system is, by definition, a shallow state nucleus. The nucleon, in most cases a neutron, is loosely bound to the other nucleons forming the core. Accordingly, the system is located inside the universal window; the halo nucleon most likely resides far from the rest of the nucleons, showing a remarkable insensitivity to details of the interaction with the core. The system can be described using a simple nucleon-core interaction, and this description can be extended to the nucleon-nucleon-core system. Specifically, treating the neutron-core and the neutron-neutron-core systems with a Gaussian interaction as a reference, we show trajectories inside the universal window governed by interaction parameters determined from low-energy observables, such as the neutron-core binding energy, scattering length, and effective range. In this way, we can relate properties of different halo nuclei that might seem uncorrelated. In particular, we determine the three-body parameter, the binding momentum at the unitary limit, and show that the two-neutron halo nuclei emerge from that limit following a linear trajectory depending on the neutron-core range.

nucl-th↗