Nuclear Theory·nucl-th

Wednesday·January 24, 2024

8 papers—5 primary·3 cross-listed

06
Femtoscopy between $π$ , $K$ and $p$ in different heavy-ion collisions at $s_{N N}$ = 39 GeV
Ting-Ting Wang🇨🇳 · Yu-Gang Ma🇨🇳 · Song Zhang🇨🇳
Momentum correlation functions between $π$ , $K$ and $p$ are calculated for several heavy-ion collision systems, namely $_{5}^{10} B +_{5}^{10} B$ , $_{8}^{16} O +_{8}^{16} O$ , $_{20}^{40} Ca +_{20}^{40} Ca$ and $_{79}^{197} Au +_{79}^{197} Au$ in central collisions as well as $_{79}^{197} Au +_{79}^{197} Au$ collision in different centralities at center of mass energy $s_{N N}$ = 39 GeV within the framework of A Multi-Phase Transport (AMPT) model complemented by the Lednick $y ˊ$ and Lyuboshitz analytical method. The results present the centrality and system-size dependence of the momentum correlation functions among pairs of $π$ , $K$ and $p$ , from which the emission source-size can be deduced. It is found that the deduced source sizes increase with the decreasing of centrality for Au + Au system or with the increasing of system-size in central collisions with different nuclear size. In addition, through the momentum correlation functions of nonidentical particle pairs gated on velocity, the average emission sequence of non-identical particles can be indicated. The results illustrate that in the small relative momentum region, protons are emitted in average earlier than $π^{+}$ and $K^{+}$ , and $K^{+}$ are emitted averagely earlier than $π^{+}$ . Furthermore, it seems that larger interval of the average emission order among them is exhibited for smaller collision systems. The present study sheds light on the dynamics of light particle emission at RHIC energy.
↳ hep-phnucl-exnucl-th1 citation
07
Understanding Gravitational Form Factors with the Weizsäcker-Williams Method
Yoshikazu Hagiwara🇨🇳 · Xuan-Bo Tong🇫🇮 · Bo-Wen Xiao🇨🇳
Understanding the internal structure of nucleons and nuclei has been a topic of enduring interest in high-energy physics. Gravitational form factors (GFFs) provide an important portal for us to probe the energy-momentum/mass distribution of nucleons and nuclei. This letter presents the study of the photon and gluon momentum GFFs, also known as the A-GFFs, of relativistic hadrons using the Weizsäcker-Williams method. To begin, we express the photon A-GFFs in terms of charge form factors and discuss the corresponding photon radius. Furthermore, an integral relation between the gluon A-GFF and the Laplacian of dipole scattering amplitude is derived in the small- $x$ framework, and it allows us to unravel the gluon energy momentum distribution inside hadrons through measurements at the upcoming Electron-Ion Collider. In addition, we generalize the analysis to study the A-GFF of nuclei and propose employing the nuclear gluon mean square radius, together with the charge distribution, to constrain the neutron distribution for large nuclei. This work provides an interesting perspective into the fundamental structure of high-energy hadrons.
↳ hep-phnucl-exnucl-thPRD(2025)·17 citations
08
Optimization and Stabilization of Functional Renormalization Group Flows
Niklas Zorbach🇩🇪 · Jonas Stoll🇩🇪 · Jens Braun🇩🇪
We revisit optimization of functional renormalization group flows by analyzing regularized loop integrals. This leads us to a principle, the Principle of Strongest Singularity, and a corresponding order relation which allows to order existing regularization schemes with respect to the stability of renormalization group flows. Moreover, the order relation can be used to construct new regulators in a systematic fashion. For studies of critical behavior, which require to follow renormalization group flows down to the deep infrared regime, such new regulators may turn out to be particularly useful. The general application of this principle is demonstrated with the aid of a scalar field theory which is solved over a wide range of scales with novel methods borrowed from numerical fluid dynamics.
↳ hep-phhep-thnucl-thPRD(2025)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE

Femtoscopy between π, K and p in different heavy-ion collisions at sNN​​ = 39 GeV

Understanding Gravitational Form Factors with the Weizsäcker-Williams Method

Optimization and Stabilization of Functional Renormalization Group Flows

Affiliations

Femtoscopy between $π$ , $K$ and $p$ in different heavy-ion collisions at $s_{N N}$ = 39 GeV