Nuclear Theory·nucl-th

Tuesday·March 12, 2024

16 papers—6 primary·10 cross-listed

07
Testing effective field theory with the most general neutron decay correlations
Chien-Yeah Seng🇺🇸
Built on the seminal works by Jackson-Treiman-Wyld and Ebel-Feldman, we derive the most general free neutron differential decay rate where all massive particles (neutron, proton and electron) are polarized. This introduces 33 new correlations in addition to the 18 existing ones, which over-constrain the coupling constants in the low-energy effective field theory of charged weak interactions, and thus provides stringent tests of the validity of the theory framework itself. We classify the correlation coefficients in terms of their Standard Model limit and discrete symmetries, and study their expansion with respect to the new physics coupling strengths, supplemented by the experiment-independent $O (α)$ virtual electromagnetic radiative corrections.
↳ hep-phhep-exnucl-exnucl-thPRD(2024)·2 citations
08
Symmetric cumulant $s c_{2, 4} {4}$ and asymmetric cumulant $a c_{2} {3}$ from transverse momentum conservation and flow
Jia-Lin Pei🇨🇳 · Guo-Liang Ma🇨🇳 · Adam Bzdak🇵🇱
Multiparticle cumulants method can be used to reveal long-range collectivity in small and large colliding systems. The four-particle symmetric cumulant $s c_{2, 4} {4}$ , three-particle asymmetric cumulant $a c_{2} {3}$ , and the normalized cumulants $n s c_{2, 4} {4}$ and $na c_{2} {3}$ from the transverse momentum conservation and flow are calculated. The interplay between the two effects is also investigated. Our results are in a good agreement with the recent ATLAS measurements of multiparticle azimuthal correlations with the subevent cumulant method, which provides insight into the origin of collective flow in small systems.
↳ hep-phnucl-exnucl-thPRC(2024)·5 citations
09
Skewed generalized parton distributions of proton from basis light-front quantization
Yiping Liu · Siqi Xu · Chandan Mondal · Xingbo Zhao · James P.Vary
We obtain all the leading-twist quark generalized parton distributions (GPDs) inside the proton at nonzero skewness within the basis light-front quantization framework. We employ the light-front wave functions of the proton from a light-front quantized Hamiltonian in the valence Fock sector consisting of a three-dimensional confinement potential and a one-gluon exchange interaction with fixed coupling. We find that the qualitative behaviors of our GPDs are similar to those of other theoretical calculations. We further examine the GPDs within the boost-invariant longitudinal coordinate, $σ = \frac{1}{2} b^{-} P^{+}$ , which is identified as the Fourier conjugate of the skewness. The GPDs in the $σ$ -space show diffraction patterns, which are akin to the diffractive scattering of a wave in optics.
↳ hep-phnucl-thPLB(2024)·25 citations
10
Shear viscosity and electric conductivity of quark matter at finite temperature and chemical potential with QCD phase transitions
Wei-be He🇨🇳 · Guo-yun Shao🇨🇳 · Chong-long Xie🇨🇳 · Ren-xin Xu🇨🇳
In the Beam Energy Scan phase II (BES-II) experiments at RHIC STAR, the quark-gluon plasma (QGP) produced with changing collision energies may probe different regions of the QCD phase diagram. Correspondingly, studying the transport coefficients of quark matter in these regions will contribute to extracting the QCD phase structure through hydrodynamic approaches. We investigate the shear viscosity and electric conductivity within the framework of kinetic theory with the relaxation time approximation, in particular their behaviors near the Mott and first-order phase transitions with a spinodal structure as well as along the isentropic trajectories. To derived the scattering cross-section under different conditions, the temperature and chemical potential dependent masses of quarks, antiquarks and exchanged mesons are calculated in the Polyakov-loop extended Nambu--Jona Lasinio (PNJL) model. The numerical results indicate that, at small chemical potential, the shear viscosity to entropy density ratio ( $η / s$ ) has a minimum near the Mott phase transition and increases rapidly in the lower-temperature side of the chiral crossover phase transition. At large chemical potential (high baryon density), $η / s$ in the QGP phase is dominated by temperature, and the value of $η / s$ is greatly enhanced at low temperatures. At intermediate temperature and chemical potential near the QCD phase transition, the behavior of $η / s$ is influenced by the competition between temperature, density, and QCD phase transition. The electirc conductivity ( $σ / T$ ) roughly exhibits similar characteristics to $η / s$ in the QCD phase diagram, whereas the dimensionless ratio of $η / s$ to $σ / T$ decreases monotonically with growing temperature, approaching a constant in the high-temperature limit.
↳ hep-phnucl-thPRD(2026)·2 citations
11
Global sensitivity analysis in Monte Carlo radiation transport
Kayla Clements · Gianluca Geraci · Aaron J Olson · Todd S Palmer
We consider Global Sensitivity Analysis for Monte Carlo radiation transport applications. GSA is usually combined with Uncertainty Quantification, where the latter quantifies the variability of a model output in the presence of uncertain inputs and the former attributes this variability to the inputs. The additional noise inherent to MC RT solvers due to the finite number of particle histories presents an additional challenge to GSA and UQ, which are well-established for deterministic solvers. In this contribution, we apply variance deconvolution to the Saltelli method to address MC RT solver noise without having to over-resolve the MC RT simulation.
↳ physics.comp-phnucl-thProceedings of The International Conferen…·0 citations
12
Transverse-momentum-dependent gluon distributions of proton within basis light-front quantization
Hongyao Yu🇨🇳 · Zhi Hu🇯🇵 · Siqi Xu🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · James P. Vary🇺🇸
Gluon transverse-momentum dependent distributions (TMDs) are very important for revealing the internal structure of the proton. They correspond to a variety of experiments and are among the major tasks of the future electron-ion colliders. In this paper, we calculate the T-even gluon TMDs at the leading twist within the Basis Light-front Quantization framework. We employ the light-front wave functions of the proton obtained from a light-front quantized Hamiltonian with Quantum Chromodynamics input determined for its valence Fock sector with three constituent quarks and an additional Fock sector, encompassing three quarks and a dynamical gluon, with a three-dimensional confinement. After obtaining the numerical results we investigate the properties of gluon TMDs by checking whether they satisfy the Mulders-Rodrigues inequalities and investigate the correlations between transverse and longitudinal degrees of freedom. With their connection to unintegrated gluon distributions in mind, we further investigate the limiting behaviours of gluon TMDs in the small- $x$ and large- $x$ regions.
↳ hep-phnucl-thPLB(2024)·20 citations
13
Transverse polarization of Lambda hyperons in hadronic collisions
Ying Gao🇨🇳 · Kai-Bao Chen🇨🇳 · Yu-Kun Song🇨🇳 · Shu-Yi Wei🇨🇳
The transverse polarization of $Λ$ hyperon within reconstructed jets in hadronic collisions offers a complementary platform to probe the polarized fragmentation function $D_{1 T}^{⊥}$ . We illustrate that by performing a global analysis of the transverse polarization of $Λ$ hyperons produced in different kinematic regions and in different hadronic collisions, such as $pp$ , $p p ˉ$ , $p A$ , and $γ A$ collisions, we can pin down the flavor dependence of $D_{1 T}^{⊥}$ which has been poorly constrained. Besides the single inclusive jet production, the $γ / Z^{0}$ -boson associated jet production supplements with more capability in removing ambiguities in the flavor dependence of $D_{1 T}^{⊥}$ .
↳ hep-phhep-exnucl-thPLB(2024)·4 citations
14
Confinement of $N$ -body systems and non-integer dimensions
E. Garrido · A.S. Jensen
The squeezing process of a three-dimensional quantum system by use of an external deformed one-body oscillator potential can also be described by the $d$ -method, without external field and where the dimension can take non-integer values. In this work we first generalize both methods to $N$ particles and any transition between dimensions below $3$ . Once this is done, the use of harmonic oscillator interactions between the particles allows complete analytic solutions of both methods, and a direct comparison between them is possible. Assuming that both methods describe the same process, leading to the same ground state energy and wave function, an analytic equivalence between the methods arises. The equivalence between both methods and the validity of the derived analytic relation between them is first tested for two identical bosons and for squeezing transitions from 3 to 2 and 1 dimensions, as well as from 2 to 1 dimension. We also investigate the symmetric squeezing from 3 to 1 dimensions of a system made of three identical bosons. We have in all the cases found that the derived analytic relations between the two methods work very well. This fact permits to relate both methods also for large squeezing scenarios, where the brute force numerical calculation with the external field is too much demanding from the numerical point of view, especially for systems with more than two particles.
↳ quant-phnucl-thphysics.atm-clusphysics.atom-phFew Body Syst.(2024)·2 citations
15
Dark matter scattering off $^{2}$ H and $^{4}$ He nuclei within chiral effective field theory
E. Filandri🇮🇹 · M. Viviani🇮🇹
We study dark matter, assumed to be composed by weak interacting massive particles (WIMPs), scattering off $^{2}$ H and $^{4}$ He nuclei. In order to parameterize the WIMP-nucleon interaction the chiral effective field theory approach is used. Considering only interactions invariant under parity, charge conjugation and time reversal, we examine five interaction types: scalar, pseudoscalar, vector, axial and tensor. Scattering amplitudes between two nucleons and a WIMP are determined up to second order of chiral perturbation theory. We apply this program to calculate the interaction rate as function of the WIMP mass and of the magnitude of the WIMP-quark coupling constants. From our study, we conclude that the scalar nuclear response functions result much greater than the others due to theirs large combination of low energy constants. We verify that the leading order contributions are dominant in this low energy processes. We also provide an estimate for the background due to atmospheric neutrinos.
↳ hep-phhep-thnucl-thPRC(2024)·1 citation
16
Gluon Double-Spin Asymmetry in the Longitudinally Polarized $p + p$ Collisions
Yuri V. Kovchegov🇺🇸 · Ming Li🇺🇸
We derive the first-ever small- $x$ expression for the inclusive gluon production cross section in the central rapidity region of the longitudinally polarized proton-proton collisions. The cross section depends on the polarizations of both protons, therefore comprising the numerator of the longitudinal double-spin asymmetry $A_{LL}$ for the produced gluons. The cross section is calculated in the shock wave formalism and is expressed in terms of the polarized dipole scattering amplitudes on the projectile and target protons. We show that the small- $x$ evolution corrections are included into our cross section expression if one evolves these polarized dipole amplitudes using the double-logarithmic helicity evolution derived in \cite{Kovchegov:2015pbl, Kovchegov:2016zex, Kovchegov:2018znm, Cougoulic:2022gbk}. Our calculation is performed for the gluon sector only, with the quark contribution left for future work. When that work is complete, the resulting formula will be applicable to longitudinally polarized proton-proton and proton-nucleus collisions, as well as to polarized semi-inclusive deep inelastic scattering (SIDIS) on a proton or a nucleus. Our results should allow one to extend the small- $x$ helicity phenomenology analysis of \cite{Adamiak:2023yhz} to the jet/hadron production data reported for the longitudinally polarized proton-proton collisions at RHIC and to polarized SIDIS measurements at central rapidities to be performed at the EIC.
↳ hep-phhep-exnucl-exnucl-thJHEP(2024)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE