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Nuclear Theory·nucl-th

Friday·May 9, 2025

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 06

    Directed flow from parton spin-orbit coupling in and collisions

    Sanjin Benić🇭🇷 · Yoshitaka Hatta🇺🇸

    We point out a novel mechanism to generate two-particle azimuthal correlation (`directed flow') in unpolarized proton-proton and proton-nucleus collisions in the forward rapidity region of the projectile proton. This is a direct consequence of the recently discovered strong spin-orbit coupling in gluons at small-. The observable simultaneously serves as a unique probe into the double helicity parton distribution functions of the proton.

    ↳ hep-phhep-exnucl-exnucl-thPLB(2025)·3 citations
  2. 07

    Theoretical characterisation of the barium II and radium II ions

    Robin B. Cserveny · Benjamin M. Roberts

    Motivated by recent experimental advances, including the ongoing development of an optical atomic clock in singly ionised radium, we perform a detailed theoretical characterisation of Ra+ and its lighter analogue, Ba+. Both ions are of interest for precision studies, including for atomic parity violation and searches for new physics beyond the standard model. Using the all-orders correlation potential method, including Breit and radiative quantum electrodynamics corrections, we perform high-accuracy calculations of electric-dipole (E1), electric-quadrupole (E2), and magnetic-dipole (M1) transition matrix elements between the low-lying s, p, and d states of these ions, as well as the excited-state lifetimes, polarizabilities, magic wavelengths, and magnetic dipole (A) hyperfine structure constants. By combining lifetime measurements with precise theoretical ratios, we extract high-accuracy determinations of the s-d_1/2 and s-d_3/2 E2 matrix elements. By combining hyperfine measurements with atomic theory, we extract parameters of the nuclear magnetisation distribution (the Bohr-Weisskopf effect) for 135-, 137-Ba and 223-, 225-Ra. These results provide theoretical input for ongoing and future experimental programs in fundamental physics and precision metrology.

    ↳ physics.atom-phnucl-thPRA(2025)·3 citations
  3. 08

    Three-dimensional femtoscopy for proton pairs in heavy-ion collisions

    Adam Kisiel🇵🇱

    Femtoscopy, a technique of measuring the size and the dynamics of the system created in heavy-ion collisions is used extensively in experiments at RHIC, LHC, SPS, and the FAIR/GSI. Analysis for pairs of pions is most common, due to their large abundance in the collisions, as well as well-understood theoretical formalism and advanced experimental methodology. It is usually performed in three dimensions in longitudinally co-moving reference frame of the pair, to maximize the amount of information obtained about the source. Similar three-dimensional analysis has also been performed for charged and neutral kaons. In contrast analyses for all other pair types -- either for pairs of identical protons, or for pairs of non-identical particles are only one-dimensional. The abundance of heavier particles is lower than for pions, while the theoretical formalism for such correlations, as well as practical experimental methodology is limited to one-dimensional case up to now. This work identifies specific challenges arising in the analysis of three-dimensional proton-proton femtoscopy and proposes a theoretical formalism to analyze them, as well as specific experimental methods to extract and fit correlations. A test and validation of these methods is performed on correlations simulated in the LHyquid+Therminator2 model, and demonstrates the feasibility of such analysis. The caveats in the theoretical interpretation of the results are discussed, by comparing the fitted values of femtscopic radii with the true characteristics of the source extracted directly from the model.

    ↳ hep-exhep-phnucl-th2 citations
  4. 09

    Theoretical modeling of approximate universality of tidally deformed neutron stars

    Takuya Katagiri🇩🇰 · Gowtham Rishi Mukkamala🇩🇰 · Kent Yagi🇺🇸

    Quasi-universal relations are known to exist among various neutron star observables that do not depend sensitively on the underlying nuclear matter equations of state. For example, some of these relations imply that the tidally induced multipole moments are approximately characterized by the electric-type quadrupolar tidal deformability. Such relations can be used to reduce the number of independent tidal parameters in gravitational-waveform modeling, thereby allowing us to infer extreme nuclear matter properties more accurately and test General Relativity in an insensitive manner to uncertainties in nuclear physics. We present a comprehensive theoretical investigation into approximate universality of neutron stars. Our approach employs a semi-analytic relativistic stellar interior model, which extends the Tolman VII solution, thereby enabling a refined exploration of the tidal properties of nonrotating stars within a semi-analytic framework. The derived power-law relations among various tidal deformabilities -- referred to as the universal Love relations -- agree well with expressions in previous work found empirically. We elucidate how the equation-of-state dependence is suppressed in a particular combination of macroscopic physical parameters induced by perturbations and demonstrate that the relation between the moment of inertia and electric-type quadrupolar tidal deformability (I-Love relation) rests on the same underlying mechanism. Our findings indicate that the approximate universality of neutron stars can be attributed to low compressibility, consistent with some of the previous studies on the possible origin of the universality.

    ↳ gr-qcastro-ph.HEnucl-exnucl-thPRD(2025)·10 citations
  5. 10

    Primordial black-hole formation and heavy r-process element synthesis from the cosmological QCD transition. Two aspects of an inhomogeneous early Universe

    M. Gonin🇩🇪 · G. Hasinger🇩🇪 · D. Blaschke🇩🇪 · O. Ivanytskyi🇵🇱 · G. Röpke🇩🇪

    We review the role of primordial black holes (PBHs) for illuminating the dark ages of the cosmological evolution and as dark matter candidates. We elucidate the role of phase transitions for primordial black hole formation in the early Universe and focus our attention to the cosmological QCD phase transition within a recent microscopical model. We explore the impact of physics beyond the Standard Model on the cosmic equation of state and the probability distribution for the formation of primordial black holes which serve as dark matter (DM) candidates. We argue that besides primordial black holes also droplet-like quark-gluon plasma inhomogeneities may become gravitationally stabilized for a sufficiently long epoch to distill baryon number and form nuclear matter droplets which upon their evaporation may enrich the cosmos locally with heavy -process elements already in the early Universe.

    ↳ hep-phastro-ph.COnucl-thEPJA(2025)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE