Nuclear Theory·nucl-th

Thursday·April 3, 2025

12 papers—6 primary·6 cross-listed

07
Towards the determination of CP-odd pion-nucleon couplings
Shohini Bhattacharya🇺🇸 · Kaori Fuyuto🇺🇸 · Emanuele Mereghetti🇺🇸 · Thomas R. Richardson🇺🇸
The nucleon matrix elements (NMEs) associated with quark chromo-magnetic dipole moments (cMDMs) play a crucial role in determining the CP-odd pion-nucleon couplings induced by quark chromo-electric dipole moments. In recent years, it has been argued that the NMEs of cMDMs can be related to the third moment of the nucleon's higher-twist (specifically, twist-three) parton distribution function (PDF) $e (x)$ , which can, in principle, be measured through dihadron production in semi-inclusive deep inelastic scattering processes. By applying the spin-flavor expansion to the cMDM operators in the large- $N_{c}$ limit, where $N_{c}$ is the number of quark colors, we show that the NMEs receive contributions not only from the twist-three PDF $e (x)$ but also from an additional, previously neglected nucleon form factor. Incorporating constraints from the spin-flavor expansion, recent experimental data on $e (x)$ , as well as model calculations of $e (x)$ , we estimate the NMEs of the cMDM operators. Our analysis indicates that the NMEs are dominated by the nucleon form factors, and the cMDM contributions to pion-nucleon couplings can be comparable to those from the quark sigma terms.
↳ hep-phhep-latnucl-exnucl-thPRC(2025)·4 citations
08
Pion Gravitational Form Factors in Holographic QCD
Mitsuru Tanaka · Daisuke Fujii · Akihiro Iwanaka
We present the first calculation of the momentum-transfer dependence of the pion gravitational form factors (GFFs) within a top-down holographic QCD framework. These form factors encode essential information about the internal stress distribution of hadrons and may serve as a tool to explore the non-perturbatice dyanmics responsible for quark and gluon confinement in QCD. In particular, we evaluate the forward-limit value of the GFFs, known as the D-term, within the framework of the Sakai-Sugimoto model. Our analysis also reveals glueball dominance, wherein the pion's gravitational interaction is mediated by an infinite tower of glueball excitations.
↳ hep-phhep-latnucl-th3 citations
09
The impact of glasma on heavy quark spectra and correlations
Dana Avramescu🇫🇮 · Vincenzo Greco🇮🇹 · Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · David. I. Müller🇦🇹
We investigate the effect of the glasma classical color fields, produced in the very early stage of heavy-ion collisions, on the transport of heavy quarks. The glasma fields evolve according to the classical Yang-Mills equations, while the dynamics of heavy quarks is described by Wong's equations. We numerically solve these equations and compute the transport coefficient $κ$ , which is anisotropic and initially very large. Further, we extract observables sensitive to the initial glasma stage. The heavy quark nuclear modification factor $R_{AA}$ is affected by the glasma but the effect is moderate compared to the nPDF contribution. Our main finding is that the glasma has a large impact on the azimuthal correlation between $Q Q$ pairs, initially produced back-to-back.
↳ hep-phhep-latnucl-thEPJ Web Conf.(2025)·0 citations
10
Precise Determination of Electric Quadrupole Moments and Isotope Shift Constants of Yb $^{+}$ in Pursuance of Probing Fundamental Physics and Nuclear Radii
B. K. Sahoo
Contemplating to register signature of a new vector boson unambiguously from the measured non-linear isotope shift (IS) effects in three recent experiments [Phys. Rev. X {\bf 12}, 021033 (2022); Phys. Rev. Lett. {\bf 128}, 163201 (2022) and Phys. Rev. Lett. {\bf 134}, 063002 (2025)], very precise values of quadrupole moments and IS constants for the $6 s^{2} S_{1/2} \to 5 d^{2} D_{3/2}$ and $6 s^{2} S_{1/2} \to 5 d^{2} D_{5/2}$ clock transitions of $^{171}$ Yb $^{+}$ are presented. This is accomplished by incorporating contributions from the computationally challenging triply excited configurations through the relativistic coupled-cluster (RCC) theory. Testament of quality atomic wave functions of states of the above transitions, obtained using the RCC theory, are gauged by comparing the calculated energies and magnetic dipole hyperfine structure constants with their measurements. The improved quadrupole moments from this work will be immensely useful to estimate quadrupole shifts of the clock transitions of Yb $^{+}$ . Complementary approaches are employed to ascertain accuracy and comprehend roles of orbital relaxation and correlation effects in evaluating the IS constants. Combining these constants with the IS measurements from Phys. Rev. Lett. {\bf 128}, 163201 (2022), differential nuclear charge radii of the Yb isotopes are inferred that deviate by 6-7\% from the literature data.
↳ physics.atom-phnucl-thphysics.comp-phPRA(2025)·4 citations
11
Isospin asymmetry and neutron stars in V-QCD
Lorenzo Bartolini🇨🇳 · Sven Bjarke Gudnason🇨🇳 · Matti Järvinen🇰🇷
Isospin asymmetric nuclear matter is introduced to V-QCD, a bottom-up holographic Quantum Chromodynamics (QCD) model. Using a small isospin chemical potential we extract the symmetry energy in the model, finding excellent agreement with experimental results for some of the potentials. Extending the calculation for finite and arbitrary sized isospin chemical potentials, we construct beta-equilibrated neutron stars via the usual Tolman-Oppenheimer-Volkov (TOV) equations. We find, pleasingly, that the neutron stars passing the mass/radius and tidal deformability constraints are those with the potentials that also lead to excellent symmetry energies.
↳ hep-phhep-thnucl-thPRD(2025)·11 citations
12
$γ^{(*)} + N (940) \frac{1}{2}^{+} \to N (1520) \frac{3}{2}^{-}$ helicity amplitudes and transition form factors
L. Albino🇪🇸 · G. Paredes-Torres🇲🇽 · K. Raya🇪🇸 · A. Bashir🇪🇸 · J. Segovia🇪🇸
We recently reported new results on the $γ^{(*)} + N (940) \frac{1}{2}^{+} \to Δ (1700) \frac{3}{2}^{-}$ transition form factors using a symmetry-preserving treatment of a vector $\otimes$ vector contact interaction (SCI) within a coupled formalism based on the Dyson-Schwinger, Bethe-Salpeter, and Faddeev equations. In this work, we extend our investigation to the $γ^{(*)} + N (940) \frac{1}{2}^{+} \to N (1520) \frac{3}{2}^{-}$ transition. Our computed transition form factors show reasonable agreement with experimental data at large photon virtualities. However, deviations emerge at low $Q^{2}$ , where experimental results exhibit a sharper variation than theoretical predictions. This discrepancy is expected, as these continuum QCD analyses account only for the quark-core of baryons, while low photon virtualities are dominated by meson cloud effects. We anticipate that these analytical predictions, based on the simplified SCI framework, will serve as a valuable benchmark for more refined studies and QCD-based truncations that incorporate quark angular momentum and the contributions of scalar and vector diquarks.
↳ hep-phhep-exhep-lathep-th+1PRD(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Towards the determination of CP-odd pion-nucleon couplings

Pion Gravitational Form Factors in Holographic QCD

The impact of glasma on heavy quark spectra and correlations

Precise Determination of Electric Quadrupole Moments and Isotope Shift Constants of Yb+ in Pursuance of Probing Fundamental Physics and Nuclear Radii

Isospin asymmetry and neutron stars in V-QCD

γ(∗)+N(940)21​+→N(1520)23​− helicity amplitudes and transition form factors

Affiliations

Precise Determination of Electric Quadrupole Moments and Isotope Shift Constants of Yb $^{+}$ in Pursuance of Probing Fundamental Physics and Nuclear Radii

$γ^{(*)} + N (940) \frac{1}{2}^{+} \to N (1520) \frac{3}{2}^{-}$ helicity amplitudes and transition form factors