Nuclear Theory·nucl-th

Tuesday·March 12, 2024

16 papers—6 primary·10 cross-listed

01
Muon Capture on $^{6}$ Li, $^{12}$ C, and $^{16}$ O from $A b I ni t i o$ Nuclear Theory
Lotta Jokiniemi🇨🇦 · Petr Navratil🇨🇦 · Jenni Kotila🇫🇮 · Kostas Kravvaris🇺🇸
Muon capture on nuclei is one of the most promising probes of the nuclear electroweak current driving the yet-hypothetical neutrinoless double-beta ( $0 ν β β$ ) decay. Both processes involve vector and axial-vector currents at finite momentum transfer, $q \sim 100$ MeV, as well as the induced pseudoscalar and weak-magnetism currents. Comparing measured muon-capture rates with reliable $ab ini t i o$ nuclear-theory predictions could help us validate these currents. To this end, we compute partial muon-capture rates for $^{6}$ Li, $^{12}$ C and $^{16}$ O, feeding the ground and excited states in $^{6}$ He, $^{12}$ B and $^{16}$ N, using $ab ini t i o$ no-core shell model with two- and three-nucleon chiral interactions. We remove the spurious center-of-mass motion by introducing translationally invariant operators and approximate the effect of hadronic two-body currents by Fermi-gas model. We solve the bound-muon wave function from the Dirac wave equations in the Coulomb field created by a finite nucleus. We find that the computed rates to the low-lying states in the final nuclei are in good agreement with the measured counterparts. We highlight sensitivity of some of the transitions to the sub-leading three-nucleon interaction terms. We also compare summed rates to several tens of final states with the measured total capture rates and note that we slightly underestimate the total rate with this simple approach due to limited range of excitation energies.
nucl-thhep-exhep-phnucl-exPRC(2024)·17 citations
02
Description of moment of inertia and the interplay between anti-pairing and pairing correlations in even-even $^{244}$ Pu and $^{248}$ Cm
Anshul Dadwal · Xiao-Tao He
Within the supersymmetry scheme, which includes many-body interactions and a perturbation possessing the SO(5) (or SU(5)) symmetry, the rotational bands of the $A \sim 250$ mass region are studied systematically. A novel modification is introduced, extending the Arima coefficient to the third order. This study is dedicated to the quantitative analysis of evolving trends in intraband $γ$ -transition energy, kinematic, and the dynamic moment of inertia within the rotational bands of $^{244}$ Pu and $^{248}$ Cm. The computed outcomes exhibit an exceptional degree of agreement with experimental observations across various conditions. The significance of including a higher-order Arima coefficient is further examined by contrasting it with the previously suggested model. The calculated results demonstrate the significance of both the anti-pairing and pairing effects in the evolution of the dynamic moment of inertia. Additionally, these insights reveal the importance of a newly introduced parameter in accurately depicting complex nuclear behaviors such as back-bending, up-bending, and the downturn in the moment of inertia.
nucl-thCPC(2024)·1 citation
03
Neutron scattering off spherical nuclei with global nonlocal dispersive optical model
B. Morillon · G. Blanchon · P. Romain · H.F. Arellano
We present a global nonlocal and dispersive optical model potential for neutron scattering off spherical nuclei with incident energies up to 250 MeV. This optical model is an extension of the non-dispersive Perey-Buck potential. The imaginary components are chosen energy-dependent and the dispersive constraints are taken into account. The surface imaginary part is nonlocal, whereas the volume imaginary part above 10 MeV is local, allowing to reproduce total cross sections and scattering data for high energies. We obtain a good description of scattering observables for target-nuclei ranging from $A = 16$ , up to $209$ . The inclusion of nonlocal spin-orbit term enables a better description of the analyzing power data relative to the local dispersive model.
nucl-thPRC(2024)·5 citations
04
Accessing the speed of sound in relativistic ultracentral nucleus-nucleus collisions using the mean transverse momentum
Fernando G. Gardim🇧🇷 · Andre V. Giannini🇧🇷 · Jean-Yves Ollitrault🇫🇷
It has been argued that the speed of sound of the strong interaction at high temperature can be measured using the variation of the mean transverse momentum with the particle multiplicity in ultracentral heavy-ion collisions. We test this correspondence by running hydrodynamic simulations at zero impact parameter with several equations of state, at several colliding energies from 0.2 TeV to 15 TeV per nucleon pair. The correspondence is found to be precise and robust for a smooth, boost-invariant fluid and an ideal detector. We discuss the differences between this ideal setup and an actual experiment. We conclude that the extraction of the speed of sound from data is reliable, and that the main uncertainty comes from our poor knowledge of the distribution of density fluctuations at the early stages of the collision.
nucl-thhep-phnucl-exPLB(2024)·21 citations
05
Investigating $D^{0}$ meson production in $p -$ Pb collisions at 5.02 TeV with a multi-phase transport model
Chao Zhang🇨🇳 · Liang Zheng🇨🇳 · ShuSu Shi🇨🇳 · Zi-Wei Lin🇺🇸
We study the production of $D^{0}$ meson in $p$ + $p$ and $p -$ Pb collisions using the improved AMPT model considering both coalescence and independent fragmentation of charm quarks after the Cronin broadening are included. After a detailed discussion of the improvements implemented in the AMPT model for heavy quark production, we show that the modified AMPT model can provide good description of $D^{0}$ meson spectra in $p -$ Pb collisions, the $Q_{pPb}$ data at different centrality and $R_{pPb}$ data in both mid- and forward (backward) rapidities. We also studied the effects of nuclear shadowing and parton cascade on the rapidity dependence of $D^{0}$ meson production and $R_{pPb}$ . Our results indicate that having the same strength of the Cronin (i.e $δ$ value) obtained from the mid-rapidity data leads to a considerable overestimation of the $D^{0}$ meson spectra and $R_{pPb}$ data at high $p_{T}$ in the backward rapidity. As a result, the $δ$ is determined via a $χ^{2}$ fitting of the $R_{pPb}$ data across various rapidities. This work lays the foundation for a better understanding of cold-nuclear-matter (CNM) effects in relativistic heavy-ion collisions.
nucl-thEPJC(2024)·5 citations
06
Neutrinoless double- $β$ decay and double Gamow-Teller transitions
Y. K. Wang🇨🇳 · P. W. Zhao🇨🇳 · J. Meng🇨🇳
The neutrinoless double- $β$ ( $0 ν β β$ ) decay and the double Gamow-Teller (DGT) transition are investigated with the state-of-the-art Relativistic Configuration-interaction Density functional theory. A strong linear correlation between the nuclear matrix elements (NMEs) of the $0 ν β β$ decay and the DGT transition is demonstrated. This linear correlation is found to originate from the similarity of the leading-order term of the $0 ν β β$ -decay operator and the DGT-transition one, as revealed by expanding the $0 ν β β$ -decay operator in terms of the spherical harmonics. The present results provide a strong support to constrain the $0 ν β β$ -decay NMEs through the double charge-exchange reactions.
nucl-thPLB(2024)·22 citations
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