Nuclear Theory·nucl-th

Tuesday·August 13, 2024

16 papers—8 primary·8 cross-listed

01
Toward Reliable $0 ν β β$ -decay Nuclear Matrix Elements: Exploring the potential of measuring $γ γ$ -transitions
Beatriz Romeo Zaragozano🇪🇸
In this work, a physics process known since quite long ago, double-gamma decay ( $γ γ$ ), has been revisited from a new perspective: providing valuable insights into neutrinoless double-beta decay ( $0 ν β β$ ) nuclear matrix elements. At the same time that an eager experimental search of $0 ν β β$ decay is underway, the nuclear and particle physics communities have made huge progress during the last years. The main goal of this thesis has been to investigate one of those approaches which is the computation of nuclear observables related to $0 ν β β$ decay as a way to help in determining and reducing the theoretical uncertainties in $0 ν β β$ -decay NMEs. This way, we have proposed that the measurement of the double magnetic dipole $γ γ$ decay from the double isobaric analog state in the $β β$ -decay final nucleus could establish the value and reduce the uncertainty in $0 ν β β$ -decay NMEs, because the NMEs of the two processes are very well correlated. We have explored the validity of this approach to predict and quantify NMEs uncertainties in the case where data is available for the nuclear observable related to $0 ν β β$ decay, that is for the Standard Model allowed $2 ν β β$ decay. A further objective has been to start with the theoretical characterization of the first steps toward the measurement of the proposed $γ γ$ double magnetic dipole decay from the double isobaric analogue state. In particular, we have studied the main decaying modes that can compete with this process: single gamma decay and proton emission, vi and we have calculated the corresponding branching ratios. In addition, we have also given the first steps in the study of the relation between $γ γ$ and $0 ν β β$ -decay NMEs in the ab initio valence space in-medium similarity renormalization group.
nucl-th1 citation
02
Applications of the Modified Hulthén-Kohn Method for Bound and Scattering States
M. A. Sharaf · A. M. Shirokov · W. Du · J. P. Vary
We apply the Hulthèn-Kohn method suggested by V. D. Efros [Phys. Rev. C 99, 034620 (2019)] for calculating various observables in the continuum and discrete spectrum using two-body interactions in single- and coupled-channel systems. This method is promising for many-body applications and ab initio description of nuclear reactions. We explore the convergence of phase shifts and wave functions as well as the location of S-matrix poles which enables obtaining both resonance and bound state parameters. We find that adopting wave functions from approximate bound-state solutions for the short-range components of basis wave functions leads to good convergence.
nucl-thPRC(2025)·5 citations
03
Constraining the competition between the deconfinement and chiral phase transitions in light of the multimessenger era
Wen-Li Yuan🇨🇳 · Bikai Gao🇯🇵 · Yan Yan🇨🇳 · Bo-Lin Li🇨🇳 · Renxin Xu🇨🇳
We extend the parity doublet model for hadronic matter and study the possible presence of quark matter inside the cores of neutron stars with the Nambu-Jona-Lasinio (NJL) model. Considering the uncertainties of the QCD phase diagram and the location of the critical endpoint, we aim to explore the competition between the chiral phase transition and the deconfinement phase transition systematically, regulated by the vacuum pressure $- B$ in the NJL model. Employing a Maxwell construction, a sharp first-order deconfinement phase transition is implemented combining the parity doublet model for the hadronic phase and the NJL model for the high-energy quark phase. The position of the chiral phase transition is obtained from the NJL model self-consistently. We find stable neutron stars with a quark core within a specific parameter space that satisfies current astronomical observations. The observations suggest a relatively large chiral invariant mass $m_{0} = 600$ MeV in the parity doublet model and a larger split between the chiral and deconfinement phase transitions while assuming the first-order deconfinement phase transition. The maximum mass of the hybrid star that we obtain is $\sim 2.2 M_{⊙}$ .
nucl-thastro-ph.HEhep-phMod.Phys.Lett.A·6 citations
04
Modified Trento initial condition and its impact on collective flows and global polarization in Cu+Au collisions
Ze-Fang Jiang🇨🇳 · Shanshan Cao🇨🇳 · Ben-Wei Zhang🇨🇳
Collective flow coefficients and spin polarization are valuable probes of the geometry and flow velocity field of the quark-gluon plasma (QGP) produced in relativistic heavy-ion collisions. Using a modified TRENTo initial condition coupled to a (3+1)-dimensional (D) viscous hydrodynamic model CLVisc, we study the directed flow and elliptic flow coefficients of hadrons, together with the global polarization of $Λ$ and $Λ ˉ$ hyperons in asymmetric Cu+Au collisions. We extend the 2D TRENTo model to the 3D space, and find that the initial tilted geometry of the QGP fireball with respect to the longitudinal direction leads to a decrease of directed flow from positive to negative values with increasing pseudorapidity, an enhancement of elliptic flow at forward and backward pseudorapidities, and a non-monotonic dependence of global polarization on the transverse momentum of hyperons. The initial longitudinal flow velocity gradient further enhances the values of directed flow and global polarization. Our model calculation provides a satisfactory description of the rapidity, transverse momentum, and centrality dependences of the directed flow of charged hadrons in Cu+Au collisions for the first time, and proposes that such asymmetric heavy-ion collisions create a better environment for studying the initial tilted geometry and longitudinal flow field of the QGP than symmetric Au+Au collisions do.
nucl-thhep-phnucl-exPRC(2025)·3 citations
05
Universal bound states and resonances with Coulomb plus short-range potentials
Shunta Mochizuki · Yusuke Nishida
We study charged particles in three dimensions interacting via a short-range potential in addition to the Coulomb potential. When the Bohr radius and the scattering length are much larger than the potential range, low-energy physics of the system becomes independent from details of the short-range potential. We develop the zero-range theory to describe such universal physics in terms of the Bohr radius and the scattering length by generalizing the Bethe-Peierls boundary condition, which is then applied to two charged particles to reveal their bound states and resonances. Infinite resonances are found for a repulsive Coulomb potential, one of which turns into a bound state with increasing inverse scattering length, whereas infinite bound states exist for an attractive Coulomb potential with no resonances at any scattering length. The zero-range theory is also applied to three equally charged particles at infinite scattering length under the variational Born-Oppenheimer approximation. We find that the effective potential between two heavy particles induced by a light particle is an inverse-square attraction at distances shorter than the Bohr radius, leading to infinite deep bound states, whereas shallow ones successively turn into resonances with increasing Coulomb repulsion.
nucl-thcond-mat.mes-hallphysics.atom-phphysics.chem-phPRC(2024)·7 citations
06
Isotropization by shock waves generation in anisotropic hydrodynamics
Aleksandr Kovalenko🇷🇺
Anisotropic hydrodynamics (aHydro) has proven successful in modeling the evolution of quark-gluon matter created in heavy-ion collisions. The hydrodynamic description of quark-gluon plasma has also been widely used to study sound phenomena, such as shock waves. It has recently been shown that initial fluctuations in energy density and supersonic partons can generate fairly strong shock waves. However, significant anisotropic properties of the system due to the rapid longitudinal expansion of matter have not been taken into account in such studies. Moreover, the process of isotropization and its characteristic time-scales were not considered along with the question of the shock waves formation. Previous studies on shock discontinuous solutions in anisotropic hydrodynamics assumed constant anisotropy, leading to flow refraction towards the anisotropy axis and flow acceleration, characteristics of rarefaction waves, indicating limitations in this approach. This paper investigates discontinuous solutions for normal shock waves without flow refraction, introducing two compression parameters for longitudinal and transverse pressures. The resulting analytical solutions, as well as numerical computations, provide an isotropization mechanism of the system.
nucl-thhep-phEPJC(2024)·0 citations
07
The Connection between the Stochastic Schrödinger Equation and Boltzmann Equation
Zichao Li · Xingbo Zhao
The heavy quarks present in the quark-gluon plasma (QGP) can act as a probe of relativistic heavy ion collisions as they retain the memory of their interaction history. In a previous study, a stochastic Schrödinger equation (SSE) has been applied to describe the transport process of heavy quarks, where an external field with random phases is used to simulate the thermal medium. In this work, we study the connection between the SSE and the Boltzmann equation (BE) approach in the Keldysh Green's function formalism. By comparing the Green's function of the heavy quark from the SSE and the Keldysh Green's functions leading to the Boltzmann equation, we demonstrate that the SSE is consistent with the Boltzmann equation in the weak coupling limit. We subsequently confirm their consistency through numerical calculations.
nucl-thhep-phNucl.Phys.Rev.(2025)·0 citations
08
On sensitivity of nucleus deformation on final-state flow harmonics
Henrique Mascalhusk🇨🇳 · Dener S. Lemos🇺🇸 · Otavio Socolowski Jr.🇧🇷 · Wei-Liang Qian🇨🇳 · Sandra S. Padula🇧🇷 · Rui-Hong Yue🇨🇳
In this work, we explore the effect of deformation of the nuclei on collective flow in relativistic heavy-ion collisions. The parameter associated with the geometrical deformation in the Glauber model is tuned to reproduce the empirical multiplicity probability distributions correctly. Subsequently, the particle spectra and collective flows for Au+Au and U+U collisions are evaluated using a hybrid hydrodynamic code CHESS. We analyze the effects of the degrees of freedom associated with the IC on the final-state flow harmonics by exploring the parameter space of the former. The connection between the deformation parameters, specifically $β_{2}$ and $β_{4}$ , and the flow anisotropies is scrutinized. In particular, deviations in elliptic flow at $p_{T} \sim 2$ GeV are observed at smaller values of $β_{2}$ in Au+Au collisions. On the other hand, for U+U collisions, the averaged overall flow harmonics are found to be less sensitive to the geometrical parameters. Despite the difference in the model's specifications, our findings largely confirm those obtained in the literature employing different approaches, which indicate that flow harmonics can be used as a sensible probe for the initial geometry fluctuations and to discriminate between different theoretical models.
nucl-thCPC(2025)·3 citations
09
Constraining twin stars with cold neutron star cooling data
Melissa Mendes🇩🇪 · Jan-Erik Christian🇩🇪 · Farrukh J. Fattoyev🇺🇸 · Jürgen Schaffner-Bielich🇩🇪
We investigate the influence of a phase transition from hadronic matter to a deconfined quark phase inside a neutron star on its cooling behaviour including the appearance of twin star solutions in the mass-radius diagram. We find that while the inferred neutrino luminosity of cold transiently-accreting star in MXB $1659 - 29$ is reproduced in all of the constructed twin star models, the luminosity of a colder source, the neutron star in SAX J $1808.4 - 3658$ , cannot be described by equations of state with quark-hadron transition densities below $1.7$ saturation density, suggesting that twin stars with such low density transitions to the quark phase are not realized in nature. We also discuss how constraints to the quark-hadron phase transition density are strongly dependent on the cooling effectiveness of neutrino reactions in the quark phase.
↳ astro-ph.HEnucl-thPRD(2025)·13 citations
10
Charged pions asymmetry from the decay of light neutral axial mesons due to interference
Fabio L. Braghin🇧🇷
Effective three meson couplings, based in flavor U(3) quark-antiquark interactions, are considered to describe two light neutral axial meson Strong decays, $A \sim f_{1} (1285)$ and $f_{1 S} (1420)$ , and the charged rho meson decay in the following channels: $A \to ρ^{\mp} (770) + π^{\pm}$ , $A \to a_{0}^{\mp} (980) + π^{\pm}$ and $ρ^{\pm} \to π^{\pm} π^{0}$ . By considering neutral meson mixings, such as $f_{1} (1285) - a_{1}^{0} (1260)$ , $f_{1 S} (1420) - a_{1}^{0} (1260)$ and $η - π^{0}$ for the channels investigated, the leading three-meson interactions may lead to decay amplitudes that undergo interference and a resulting ratio of decay rate into charged pions, $Γ_{π^{+}} / Γ_{π^{-}}$ , slightly smaller than one. For that it will be assumed that the produced charged vector mesons or charged scalar mesons undergo absorption, decay into channels without charged pions, or any other inelastic process that may suppress their decays into charged pions.
↳ hep-phnucl-thJ.Phys.G(2025)·1 citation
11
Nuclear Burning in Accretion Flow of Helium-rich matter onto Compact Objects
Toshikazu Shigeyama · Akira Dohi
We investigate the impacts of nuclear burning on the spherically symmetric stationary accretion flow of helium-rich matter on to compact objects. We have already shown the existence of the critical accretion rates for the accretion of CO-rich matter above which the flow truncates in the supersonic region due to nuclear burning in the previous paper \citep{2022ApJ...933...29N}. Here, we show that there are also critical accretion rates for helium-rich matter. While we used empirical formulae for the energy generation rates for carbon burning and oxygen burning without solving the nuclear reaction network in our previous work, we solve a simple nuclear reaction network consisting of 13 elements from $^{4}$ He to $^{56}$ Ni to investigate influence of the energy generation from not only triple- $α$ reactions but also the subsequent reactions of synthesized elements. We have also qualitatively confirmed the previous results for CO-rich matter accretion using the revised code with the nuclear reaction network and reported some new findings.
↳ astro-ph.SRastro-ph.HEnucl-th0 citations
12
Systematic Uncertainties from Gribov Copies in Lattice Calculation of Parton Distributions in the Coulomb gauge
Xiang Gao🇺🇸 · Jinchen He🇺🇸 · Rui Zhang🇺🇸 · Yong Zhao🇺🇸
Recently, it has been proposed to compute parton distributions from boosted correlators fixed in the Coulomb gauge within the framework of Large-Momentum Effective Theory. This method does not involve Wilson lines and could greatly improve the efficiency and precision of lattice QCD calculations. However, there are concerns about whether the systematic uncertainties from Gribov copies, which correspond to the ambiguity in lattice gauge-fixing, are under control. This work gives an assessment of the Gribov copies' effect in the Coulomb-gauge-fixed quark correlators. We utilize different strategies for the Coulomb-gauge fixing, selecting two different groups of Gribov copies based on the lattice gauge configurations. We test the difference in the resulted spatial quark correlators in the vacuum and a pion state. Our findings indicate that the statistical errors of the matrix elements from both Gribov copies, regardless of the correlation range, decrease proportionally to the square root of the number of gauge configurations. The difference between the strategies does not show statistical significance compared to the gauge noise. This demonstrates that the effect of the Gribov copies can be neglected in the practical lattice calculation of the quark parton distributions.
↳ hep-lathep-phnucl-thChin.Phys.Lett.(2024)·11 citations
13
Quantum corrections at second order in derivatives to the dynamics of small non-relativistic fluids
Lars H. Heyen🇩🇪 · Giuliano Giacalone🇩🇪 · Stefan Floerchinger🇩🇪
To capture the dynamics of macroscopic non-relativistic fluids consisting of very many atoms, it is typically sufficient to truncate the gradient expansion at order zero, leading to ideal fluid dynamics, or at order one, leading to the Navier-Stokes theory. For mesoscopic fluids consisting of a small number of atoms, second-order corrections can become significant. We investigate here specifically superfluids at vanishing temperature, and identify relevant second-order terms of quantum origin that contribute already in a static situation. The general form of these terms arises from an extension of the Gross-Pitaevskii theory. In the context of density functional theory, they are named after C. von Weizsäcker. We assess the influence of these terms on numerical solutions of second-order fluid dynamic equations for the expansion of a mesoscopic ultra-cold Fermi gas released from an anisotropic harmonic trap in two spatial dimensions.
↳ cond-mat.quant-gasnucl-thquant-phPRC(2025)·1 citation
14
Nonperturbative four-gluon vertex in soft kinematics
A. C. Aguilar🇧🇷 · F. De Soto🇪🇸 · M. N. Ferreira🇨🇳 · J. Papavassiliou🇪🇸 · F. Pinto-Gómez🇪🇸 · J. Rodríguez-Quintero🇪🇸 · L. R. Santos🇧🇷
We present a nonperturbative study of the form factor associated with the projection of the full four-gluon vertex on its classical tensor, for a set of kinematics with one vanishing and three arbitrary external momenta. The treatment is based on the Schwinger-Dyson equation governing this vertex, and a large-volume lattice simulation, involving ten thousand gauge field configurations. The key hypothesis employed in both approaches is the ``planar degeneracy'', which classifies diverse configurations by means of a single variable, thus enabling their meaningful ``averaging''. The results of both approaches show notable agreement, revealing a considerable suppression of the averaged form factor in the infrared. The deviations from the exact planar degeneracy are discussed in detail, and a supplementary variable is used to achieve a more accurate description. The effective charge defined through this special form factor is computed within both approaches, and the results obtained are in excellent agreement.
↳ hep-phhep-lathep-thnucl-thPLB(2024)·9 citations
15
Prominent bump in the two-neutron separation energies of neutron-rich lanthanum isotopes revealed by high-precision mass spectrometry
A. Jaries🇫🇮 · M. Stryjczyk🇫🇮 · A. Kankainen🇫🇮 · T. Eronen🇫🇮 · O. Beliuskina🇫🇮 · T. Dickel🇩🇪 · M. Flayol🇫🇷 · Z. Ge🇫🇮 · M. Hukkanen🇫🇮 · M. Mougeot🇫🇮 · S. Nikas🇫🇮 · I. Pohjalainen🇫🇮 and 4 other authors
We report on high-precision atomic mass measurements of $^{148 - 153}$ La and $^{151}$ Ce performed with the JYFLTRAP double Penning trap using the Phase-Imaging Ion-Cyclotron-Resonance technique. The masses of $^{152, 153}$ La were experimentally determined for the first time. We confirm the sharp kink in the two-neutron separation energies at the neutron number $N = 93$ in the cerium ( $Z = 58$ ) isotopic chain. Our precision mass measurements of the most exotic neutron-rich lanthanum ( $Z = 57$ ) isotopes reveal a sudden increase in two-neutron separation energies from $N = 92$ to $N = 93$ . Unlike in the cerium isotopic chain, the kink is not sharp but extends to $N = 94$ forming a prominent bump. The gain in energy is about 0.4 MeV, making it one of the strongest changes in two-neutron separation energies over the whole chart of nuclides, away from nuclear shell closures. The results call for further studies to elucidate the structure of neutron-rich lanthanum isotopes.
↳ nucl-exnucl-thPRL(2025)·7 citations
16
Dissecting Lepton Number Violating Interactions in the Left-Right Symmetric Model: $0 ν β β$ decay, Møller scattering, and collider searches
Gang Li🇨🇳 · Michael J. Ramsey-Musolf🇺🇸 · Sebastián Urrutia Quiroga🇺🇸 · Juan Carlos Vasquez🇺🇸
In the context of the left-right symmetric model, we study the interplay of neutrinoless double beta ( $0 ν β β$ ) decay, parity-violating Møller scattering, and high-energy colliders, resulting from the Yukawa interaction of the right-handed doubly-charged scalar to electrons, which could evade the severe constraints from charged lepton flavor violation. The $0 ν β β$ decay amplitude receives additional contributions from right-handed sterile neutrinos. The half-life, calculated in the effective field theory (EFT) framework, allows for an improved description of the contributions involving non-zero mixing between left- and right-handed $W$ bosons and those arising from exchanging a light right-handed neutrino. We find that the relative sensitivities between the low-energy (or high-precision) and high-energy experiments are affected by the left-right mixing. On the other hand, our results show how the interplay of collider and low-energy searches provides a manner to explore regions that are inaccessible to $0 ν β β$ decay experiments.
↳ hep-phnucl-exnucl-thPLB(2026)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE