Nuclear Theory·nucl-th

Friday·February 2, 2024

13 papers—2 primary·11 cross-listed

03
Coulomb-nuclear interference in elastic proton scattering in the eikonal approach
M. L. Nekrasov🇷🇺
We find exact solution in the Cahn eikonal model, which describes Coulomb-nuclear interference in elastic scattering of charged hadrons. The cases of both point-like and extended particles equipped with electromagnetic form factors are considered. According to the solution obtained the Coulomb-nuclear contributions are not exponentiated and cannot be added to the Coulomb phase. At the same time, the $O (α)$ -approximation of the amplitude is ambiguous, which makes it unsuitable for data processing.
↳ hep-phhep-thPLB(2024)·4 citations
04
The development of the concept of exchange forces in the 1930s: close encounters between Europe and Japan and the birth of nuclear theory
Marco Di Mauro · Salvatore Esposito · Adele Naddeo
The onset and the development of the concept of exchange force in quantum physics are historically reconstructed, starting from Heisenberg's seminal contributions in 1926 and going through the great developments in nuclear physics, which allowed the emergence of the idea of force mediating virtual quanta. Although most of such work was performed in Europe, the last and decisive effort in this long path was carried out by Japanese scientists in the 1930s. This is the main focus of the present work, which retraces the achievements of Yukawa and Tomonaga, whose results and mutual interactions are carefully analyzed and related to those of European physicists.
↳ physics.hist-phhep-phnucl-thEur.Phys.J.H(2024)·2 citations
05
The parity-odd structure function of nucleon from the Compton amplitude
K. U. Can · R. Horsley · Y. Nakamura · P. E. L. Rakow · G. Schierholz · H. Stüben · R. D. Young · J. M. Zanotti
The dominant contribution to the theoretical uncertainty in the extracted weak parameters of the Standard Model comes from the hadronic uncertainties in the electroweak boxes, i.e. $γ - W^{\pm} / Z$ exchange diagrams. A dispersive analysis relates the box diagrams to the parity-odd structure function, $F_{3}$ , for which the experimental data either do not exist or belong to a separate isospin channel. Therefore a first-principles calculation of $F_{3}$ is highly desirable. In this contribution, we report on the QCDSF/UKQCD Collaboration's progress in calculating the moments of the $F_{3}^{γ Z}$ structure function from the forward Compton amplitude at the SU(3) symmetric point.
↳ hep-lathep-phnucl-thPoS(2025)·0 citations
06
Pion Electromagnetic Form Factor from Bethe-Salpeter Amplitudes with Appropriate Kinematics
Shaoyang Jia🇺🇸 · Ian Cloët🇺🇸
Within the framework provided by quantum chromodynamics's Schwinger-Dyson equations (SDEs), the pion's electromagnetic form factor is computed using solutions of the Bethe-Salpeter equation (BSE) that have finite spacial momentum, and therefore allow the appropriate kinematics for a given momentum transfer. This removes, for the first time, a limiting approximation in previous SDE calculations where rest-frame solutions to the BSE are used for both the initial and final pion states. In performing these calculations, the rainbow-ladder truncation to the SDEs in the Landau gauge is used, with the quark-gluon interaction given by the Maris-Tandy model. Using Bethe-Salpeter amplitudes (BSAs) that have the correct spacial momentum for a given momentum transfer, $Q^{2}$ , has a dramatic impact on results for the pion's electromagnetic form factor. The difference between results that use rest-frame BSAs and those with correct kinematics is less that 10\% for $0 ⩽ Q^{2} ≲ 1$ GeV $^{2}$ , however, these corrections grow with increasing momentum transfer and approach 100\% for $Q^{2} ≃ 3$ GeV $^{2}$ .
↳ hep-phnucl-th4 citations
07
Electromagnetic and gravitational form factors of the nucleon
Cédric Lorcé (Ecole Polytechnique)🇫🇷
Form factors are Lorentz invariant functions describing the internal structure of a system. In particular, they encode how physical properties like, e.g., charge, energy, momentum, and pressure are spatially distributed. While nucleon electromagnetic form factors have been studied for a long time, the first extraction of nucleon gravitational form factors from experimental data was reported in 2018, triggering a lot of enthusiasm and attention in the hadronic community. In this contribution we review some theoretical bases, discuss recent developments regarding the physical interpretation of these form factors, and give a glimpse of what can be learned about the mass and spin structure of the nucleon.
↳ hep-phnucl-thPoS(2024)·9 citations
08
Sound velocity peak induced by the chiral partner in dense two-color QCD
Mamiya Kawaguchi🇨🇳 · Daiki Suenaga🇯🇵
Recently, the peak structure of the sound velocity was observed in the lattice simulation of two-color and two-flavor QCD at the finite quark chemical potential. The comparison with the chiral perturbation theory (ChPT) result was undertaken, however, the ChPT failed in reproducing the peak structure. In this study, to extend the ChPT framework, we incorporate contributions of the $σ$ meson, that is identified as the chiral partner of pions, on top of the low-energy pion dynamics by using the linear sigma model (LSM). Based on the LSM we derive analytic expressions of the thermodynamic quantities as well as the sound velocity within a mean-field approximation. As a result, we find that those quantities are provided by sums of the ChPT results and corrections, where the latter is characterized by a mass difference between the chiral partners, the $σ$ meson and pion. The chiral partner contributions are found to yield a peak in the sound velocity successfully. We furthermore show that the sound velocity peak emerges only when $m_{σ} > 3 m_{π}$ and $μ_{q} > m_{π}$ , with $m_{σ (π)}$ and $μ_{q}$ being the $σ$ meson (pion) mass and the quark chemical potential, respectively. The correlation between the sound velocity peak and the sign of the trace anomaly is also addressed.
↳ hep-phhep-latnucl-thPRD(2024)·15 citations
09
Octet baryon and heavy meson interactions in chiral effective field theory
Bo-Lin Huang🇨🇳 · Bo Wang🇨🇳 · Shi-Lin Zhu🇨🇳
We calculate the effective potentials of the octet baryon and heavy meson systems using the chiral effective field theory up to the next-to-leading order. We consider the contact terms, one-pseudoscalar-meson and two-pseudoscalar-meson exchange contributions, facilitating a comprehensive analysis of the short-, mid-, and long-range interactions in these systems. The low energy constants are correlated with those of the $N ˉ N$ interaction using a quark-level Lagrangian approach. We also incorporate the decuplet baryon contributions in the loop diagrams. Our research provides new insights into several near-threshold charmed baryons [e.g., $Λ_{c} (2940)$ , $Ξ_{c} (3055)$ , and $Ω_{c} (3188)$ , etc.] around $3$ GeV from the hadronic molecular perspective. We also observe several molecular states, referred to as $Ξ_{c}$ , within the mass range of $3100 - 3500$ MeV. Further measurements of their resonance parameters and decay patterns in experiments may help to discriminate the conventional baryon and hadronic molecule explanations for these near-threshold states.
↳ hep-phhep-exnucl-thPRD(2024)·3 citations
10
Testing the Number of Neutrino Species with a Global Fit of Neutrino Data
Manuel Ettengruber🇩🇪 · Alan Zander🇩🇪 · Philipp Eller🇩🇪
We present the first experimental constraints on models with many additional neutrino species in an analysis of current neutrino data. These types of models are motivated as a solution to the hierarchy problem by lowering the species scale of gravity to TeV. Additionally, they offer a natural mechanism to generate small neutrino masses and provide interesting dark matter candidates. This study analyzes data from DayaBay, KamLAND, MINOS, NOvA and KATRIN. We do not find evidence for the presence of any additional neutrino species, therefore we report lower bounds on the allowed number of neutrino species realized in nature. For the normal/inverted neutrino mass ordering, we can give a lower bound on the number of neutrino species of O(30) and O(100), respectively, over a large range of the parameter space.
↳ hep-phhep-exnucl-thPRD(2024)·7 citations
11
Estimate for the bulk viscosity of strongly coupled quark matter using perturbative QCD and holography
Jesús Cruz Rojas🇰🇷 · Tyler Gorda🇩🇪 · Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · Matti Järvinen🇰🇷 · Aleksi Kurkela🇳🇴 · Risto Paatelainen🇫🇮 · Saga Säppi🇩🇪 · Aleksi Vuorinen🇫🇮
Modern hydrodynamic simulations of core-collapse supernovae and neutron-star mergers require knowledge not only of the equilibrium properties of strongly interacting matter, but also of the system's response to perturbations, encoded in various transport coefficients. Using perturbative and holographic tools, we derive here an improved weak-coupling and a new strong-coupling result for the most important transport coefficient of unpaired quark matter, its bulk viscosity. These results are combined in a simple analytic pocket formula for the quantity that is rooted in perturbative Quantum Chromodynamics at high densities but takes into account nonperturbative holographic input at neutron-star densities, where the system is strongly coupled. This expression can be used in the modeling of unpaired quark matter at astrophysically relevant temperatures and densities.
↳ hep-phastro-ph.HEhep-thnucl-thPRL(2024)·35 citations
12
Cylindrically symmetric diffusion model for relativistic heavy-ion collisions
Johannes Hoelck🇩🇪 · Georg Wolschin🇩🇪
A relativistic diffusion model with cylindrical symmetry, which propagates an initial state based on quantum chromodynamics in time towards a thermal equilibrium limit, is derived from nonequilibrium-statistical considerations: Adapting an existing framework for Markovian stochastic processes representing relativistic phase-space trajectories, a Fokker-Planck equation is obtained for the time evolution of particle-number distribution functions with respect to transverse and longitudinal rapidity. The resulting partially-evolved distribution functions are transformed to transverse-momentum and pseudorapidity space, and compared with charged-hadron data from the CERN Large Hadron Collider (LHC).
↳ hep-phnucl-thAnnalen Phys.(2024)·5 citations
13
Scattering wave packets of hadrons in gauge theories: Preparation on a quantum computer
Zohreh Davoudi🇺🇸 · Chung-Chun Hsieh🇺🇸 · Saurabh V. Kadam🇺🇸
Quantum simulation holds promise of enabling a complete description of high-energy scattering processes rooted in gauge theories of the Standard Model. A first step in such simulations is preparation of interacting hadronic wave packets. To create the wave packets, one typically resorts to adiabatic evolution to bridge between wave packets in the free theory and those in the interacting theory, rendering the simulation resource intensive. In this work, we construct a wave-packet creation operator directly in the interacting theory to circumvent adiabatic evolution, taking advantage of resource-efficient schemes for ground-state preparation, such as variational quantum eigensolvers. By means of an ansatz for bound mesonic excitations in confining gauge theories, which is subsequently optimized using classical or quantum methods, we show that interacting mesonic wave packets can be created efficiently and accurately using digital quantum algorithms that we develop. Specifically, we obtain high-fidelity mesonic wave packets in the $Z_{2}$ and $U (1)$ lattice gauge theories coupled to fermionic matter in 1+1 dimensions. Our method is applicable to both perturbative and non-perturbative regimes of couplings. The wave-packet creation circuit for the case of the $Z_{2}$ lattice gauge theory is built and implemented on the Quantinuum H1-1 trapped-ion quantum computer using 13 qubits and up to 308 entangling gates. The fidelities agree well with classical benchmark calculations after employing a simple symmetry-based noise-mitigation technique. This work serves as a step toward quantum computing scattering processes in quantum chromodynamics.
↳ quant-phhep-lathep-phnucl-thQuantum(2024)·90 citations

Affiliations

first authorsco-authorsvia INSPIRE