PaperPanorama

Nuclear Theory·nucl-th

Wednesday·August 28, 2024

14 papers7 primary·7 cross-listed

  1. 01

    Tunneling half-lives in macroscopic-microscopic picture

    Samyak Jain · A. Bhagwat

    Tunneling half lives are obtained in a minimalistic deformation picture of nuclear decays. As widely documented in other deformation models, one finds that the effective mass of the nucleus changes with the deformation parameter. However, contrary to the approach used in literature, a position-dependant mass potentially makes using WKB tunneling probabilities unreliable for estimating nuclear lifetimes. We instead use a new approach, a combination of the Transmission Matrix and WKB methods, to estimate tunneling probabilities. Because of the simplistic nature of the model, the calculated lifetimes are not accurate, however, the relative trends in the lifetimes of isotopes of individual nuclei are found to be consistent. Using this, we develop an empirical scaling to obtain the actual half-lives, and find the primary scaling parameter to have remarkably consistent values for all nuclei considered. The new tunneling method proposed here, which produces very different probabilities as compared to the usual WKB approach, is another key result of this work, and can be utilized for arbitrary potentials and mass variations.

    nucl-thquant-ph0 citations
  2. 02

    Two-Body Triton Photodisintegration and Wigner-SU(4) Symmetry

    Xincheng Lin · Jared Vanasse

    We calculate the two-body triton photodisintegration cross section as a function of photon energy to next-to-next-to leading order (NNLO) in pionless effective field theory (EFT()) and show good agreement with experiment. In addition we calculate the polarization asymmetry in cold neutron-deuteron capture to NNLO in EFT(), in agreement with the experimental value of [M. W. Konijnenberg et al. in Phys. Lett. B 205, 215 (1988)]. We also assess the dependence of on different fits of the two-nucleon magnetic currents. Finally, we consider the impact of Wigner-SU(4) symmetry and demonstrate that starting from the Wigner-SU(4) symmetric limit and including perturbative corrections to the breaking of Wigner-SU(4) symmetry does a good job of describing two-body triton photodisintegration.

    nucl-thPRC(2025)·5 citations
  3. 03

    Interrelation between -Ca Atom Spectra and Nuclear Density Profiles

    Kenta Yoshimura · Shunsuke Yasunaga · Daisuke Jido · Junko Yamagata-Sekihara · Satoru Hirenzaki

    This work studies -Ca atom spectra in light of the strong shifts and level widths, using the optical model with several types of parametric coefficients. The spectroscopic quantities are obtained as the eigenvalues of the Dirac equation, where the nuclear densities computed via nuclear Density Functional Theory and the effect of the anomalous magnetic moment are incorporated. The results indicate that the isovector term's contribution to the optical potential is crucial for explaining the systematical differences in the strong shifts between Ca and Ca. Furthermore, it is found that both the strong shifts and the level widths exhibit significant dependence on the nuclear density profiles. These findings provide critical insights into the nuclear structures, particularly in the context of Calcium isotopes, by offering a more comprehensive understanding of the underlying nuclear-hadron properties.

    nucl-thPTEP(2025)·4 citations
  4. 04

    De-excitations of highly excited B and N based on the GEMINI++ code

    Yujie Niu · Wan-Lei Guo · Miao He · Jun Su

    Nuclear de-excitations associated with neutrino-nucleus interactions and nucleon decays are playing an increasingly significant role in neutrino experiments. We explore the GEMINI++ code and estimate its ability to account for the de-excitation processes of highly excited B and N, which can be created in the liquid scintillator and water Cherenkov detectors respectively. It is found that GEMINI++ can not describe the nuclear experimental data of B and N well. To improve its performance for de-excitations of light nuclei, we modify GEMINI++ and then develop a code of GEMINI++4, which can give the best predictions compared with experimental measurements among some widely used statistical model codes.

    nucl-thhep-exhep-phPLB(2025)·1 citation
  5. 05

    Sources of longitudinal flow decorrelations in high-energy nuclear collisions

    Jiangyong Jia🇺🇸 · Shengli Huang🇺🇸 · Chunjian Zhang🇺🇸 · Somadutta Bhatta🇺🇸

    The longitudinal structure of the quark-gluon plasma (QGP) consists of several components spanning various scales. However, its short-range features are often obscured by final-state non-flow correlations. Here, we introduce a data-driven approach to separate initial state structures from non-flow effects. The longitudinal structure is found having two distinct components: one that reflects the global twisted geometry of the QGP, and another that captures localized fluctuations in rapidity. The characteristics of this second component, contributing to short- and medium-range flow decorrelations, can be quantified by comparing collisions of nuclei with different shapes. This study represents the first successful attempt to disentangle long- and short-range flow decorrelations from non-flow backgrounds, providing new insights into the initial conditions of heavy-ion collisions.

    nucl-thhep-phnucl-ex13 citations
  6. 06

    Polaronic neutron in dilute alpha matter: A -wave Bose polaron

    Hiroyuki Tajima · Hajime Moriya · Tomoya Naito · Wataru Horiuchi · Eiji Nakano · Kei Iida

    We theoretically investigate quasiparticle properties of a neutron immersed in an alpha condensate, which is one of the possible states of dilute symmetric nuclear matter. The resonant -wave neutron-alpha scattering, which plays a crucial role in forming halo nuclei, is considered. This system is similar to a Bose polaron near the -wave Feshbach resonance that can be realized in cold-atomic experiments. Calculating the self-energy within the field-theoretical approach, we give an analytical formula for the effective mass of a polaronic neutron as a function of alpha condensation density. Moreover, two adjacent neutrons in a medium, each of which behaves like a stable polaron having an enhanced effective mass, can form a bound dineutron, with the help of neutron-neutron attraction. This is in contrast to the case of the vacuum, where a dineutron is known to be unbound. Our result would be useful for understanding many-body physics in astrophysical environments as well as the formation of multi-nucleon clusters in neutron-halo nuclei.

    nucl-thcond-mat.quant-gasphysics.atom-phPRC(2025)·2 citations
  7. 07

    Why do newer degrees of freedom appear in higher-order truncated hydrodynamic theory?

    Sukanya Mitra🇮🇳

    An exact derivation of relativistic hydrodynamics from an underlying microscopic theory has been shown to be an all-order theory. From the relativistic transport equation of kinetic theory, the full expressions of hydrodynamic viscous fluxes have been derived which turn out to include all orders of out-of-equilibrium derivative corrections. It has been shown, that for maintaining causality, it is imperative that the temporal derivatives must include all orders, which can be resummed in non-local, relaxation operator-like forms and finally `integrated in' introducing newer degrees of freedom. The theory can of course be truncated at any higher spatial orders, but the power over the the infinite temporal sum increases correspondingly such that the causality is respected. As a result, the theory truncated at any higher order of spatial gradient, requires newer degrees of freedom for each increasing order.

    nucl-thgr-qchep-phhep-thPLB(2025)·4 citations
  8. 08

    Long Range Energy-energy Correlator at the LHC

    Yuxun Guo🇺🇸 · Xiaohui Liu🇨🇳 · Feng Yuan🇺🇸

    We study the forward-backward azimuthal angular correlations of hadrons in association with multi-particle production in the central rapidity region in proton-proton collisions at the LHC. We apply the nucleon energy-energy correlator framework, where the spinning gluon distribution introduces a nontrivial asymmetries. We will demonstrate that the fundamental helicity structure of QCD amplitudes predicts a unique power counting rule: asymmetry starts at order for dijet, for three jet and for four (and more) jet productions. Our results will help us to understand the long standing puzzle of nearside ridge behavior observed in high multiplicity events of collisions at the LHC.

    hep-phhep-exnucl-exnucl-thPRD(2025)·11 citations
  9. 09

    The impact of dark matter on tidal signatures in neutron star mergers with Einstein Telescope

    Hauke Koehn · Edoardo Giangrandi · Nina Kunert · Rahul Somasundaram · Violetta Sagun · Tim Dietrich

    If dark matter (DM) accumulates inside neutron stars (NS), it changes their internal structure and causes a shift of the tidal deformability from the value predicted by the dense-matter equation of state (EOS). In principle, this shift could be observable in the gravitational-wave (GW) signal of binary neutron star (BNS) mergers. We investigate the effect of fermionic, non-interacting DM when observing a large number of GW events from DM-admixed BNSs with the precision of the proposed Einstein telescope (ET). Specifically, we study the impact on the recovery of the baryonic EOS and whether DM properties can be constrained. For this purpose, we create event catalogues of BNS mock events with DM fraction up to 1%, from which we reconstruct the posterior uncertainties with the Fisher matrix approach. Using this data, we perform joint Bayesian inference on the baryonic EOS, DM particle mass, and DM particle fraction in each event. Our results reveal that when falsely ignoring DM effects, the EOS posterior is biased towards softer EOSs, though the offset is rather small. Further, we find that within our assumptions of our DM model and population, ET will likely not be able to test the presence of DM in BNSs, even when combining many events and adding Cosmic Explorer (CE) to the next-generation detector network. Likewise, the potential constraints on the DM particle mass will remain weak because of degeneracies with the fraction and EOS.

    astro-ph.HEgr-qcnucl-thPRD(2024)·26 citations
  10. 10

    Effect of quark anomalous magnetic moment on neutral dense quark matter under magnetic field

    Mamiya Kawaguchi🇨🇳 · Irfan Siddique🇨🇳 · Mei Huang🇨🇳

    We discuss the effect of the quark anomalous magnetic moment (AMM) on the neutral dense quark matter under magnetic fields based on the Nambu-Jona-Lasinio (NJL) model at finite baryon density. To address its correlation with the chiral symmetry, we consider a simplified situation: the model includes the two-quark flavors under constant magnetic fields, and incorporates the effective interaction of the quark AMM linked to the spontaneous chiral symmetry breaking. We then examine the equation of state (EoS) in cases with and without magnetization for anatomizing the thermodynamic quantities. Without the magnetization, a small magnetic field stiffens the EoS, but with increasing the magnetic field, the EoS tends to soften. The stiffness of the EoS is found to be influenced by the magnetic effect on the critical chemical potential of the chiral phase transition and the quark number density at this critical point. As a result, the mass and radius of the neutral dense quark matter increase with the small magnetic field but turn to decrease as the magnetic field further increases. By including the quark AMM, the critical chemical potential is decreased and the quark number density takes a smaller value. Thus, for the stronger magnetic fields, the quark AMM suppresses the softening effect of the magnetic field on the EoS, leading to increased mass and radius compared to when the quark AMM is absent. In contrast, for the small magnetic field, the contribution of the quark AMM to the EoS is marginal. When the magnetization is taken into account, the magnetic effect on the stiffness of the EoS is overshadowed by the contribution of the magnetization, and the significance of the quark AMM also becomes invisible in the mass-radius relation.

    hep-phnucl-thEPJC(2025)·8 citations
  11. 11

    A multi-band study of pulsar glitches with Fermi-LAT and Parkes

    P. Liu · J.-P. Yuan · M.-Y. Ge · W.-T. Ye · S.-Q. Zhou · S.-J. Dang · Z.-R. Zhou · E. Gügercinoğlu · Z. H. Tu · P. Wang · A. Li · D. Li · N. Wang

    Pulsar glitch is a phenomenon characterized by abrupt changes in the spin period over less than a minute. We present a comprehensive analysis of glitches in four gamma-ray pulsars by combining the timing observation data from \textit{Fermi} Large Area Telescope (\textit{Fermi}-LAT) and Parkes 64 m radio telescope. The timing data of five pulsars, namely PSRs J10285819, J14206048, J15095850, J17094429 (B170644) and J17183825, are examined over 14 yr of observations for each. A total of 12 glitches are identified in four pulsars, including a previously unreported glitch. That is, a new small glitch is identified for PSR J17183825 in MJD 59121(8), with a fractional glitch size of . For PSR J14206048, our investigation confirms the presence of two linear recovery terms during the evolution of following glitches 4, 6 and 8. Moreover, an exponential recovery process was identified after glitch 8, with a recovery fraction () of and a corresponding timescale of d. Regarding the fourth glitch of PSR J17094429, our analysis reveals the presence of two exponential recovery terms with degree of recovery and decay time-scales 1 = 0.0104(5), d and 2 = 0.006(1), d, respectively. For the remaining previously reported glitches, we also refine the glitch epochs and recovery process through precise fitting of the timing data. We discuss how multi-band data of glitches can help better characterize the glitch recoveries and constrain the underlying physics of glitch events. Our findings demonstrate that the accumulation of observational data reveals the rich complexity of the glitch phenomenon, aiding in the search for a well-established interpretation.

    astro-ph.HEnucl-thMNRAS(2025)·10 citations
  12. 12

    Speed of sound bounds and first-order phase transitions in compact stars

    P. Laskos-Patkos · G.A. Lalazissis · Sibo Wang · Jie Meng · Peter Ring · Ch.C. Moustakidis

    In the present study, we employ three distinct, physically motivated speed of sound bounds to construct hybrid models, where the high-density phase is described by the maximally stiff equation of state. In particular, we consider the bounds related to special relativity, relativistic kinetic theory and conformality. The low-density hadronic phase is described by a state-of-the-art microscopic relativistic Brueckner-Hartree-Fock theory. This work aims to access the effect of the different speed of sound constraints on the relevant parameter space of the key parameters of first-order phase transitions by utilizing recent astronomical data. This involves a systematic analysis that also includes two distinct schemes for the construction of hybrid models (abrupt and smooth). Finally, a relevant discussion is conducted on the possible occurrence of a thermodynamic inconsistency that is related to the stability of the high-density phase over hadronic matter at large densities.

    astro-ph.HEgr-qcnucl-thPRC(2025)·21 citations
  13. 13

    Simultaneously Constraining the Neutron Star Equation of State and Mass Distribution through Multimessenger Observations and Nuclear Benchmarks

    Bhaskar Biswas · Stephan Rosswog

    With ongoing advancements in nuclear theory and experimentation, together with a growing body of neutron star (NS) observations, a wealth of information on the equation of state (EOS) for matter at extreme densities has become accessible. Here, we utilize a hybrid EOS formulation that combines an empirical parameterization centered around the nuclear saturation density with a generic three-segment piecewise polytrope model at higher densities. We incorporate data derived from chiral effective field theory (EFT), perturbative quantum chromodynamics (pQCD), and from experiments such as PREX-II and CREX. Furthermore, we examine the influence of a total of 129 NS mass measurements up to April 2023, as well as simultaneous mass and radius measurements derived from the X-ray emission from surface hot spots on NSs. Additionally, we consider constraints on tidal properties inferred from the gravitational waves emitted by coalescing NS binaries. To integrate this extensive and varied array of constraints, we utilize a hierarchical Bayesian statistical framework to simultaneously deduce the EOS and the distribution of NS masses. We find that incorporating data from EFT significantly tightens the constraints on the EOS of NSs near or below the nuclear saturation density. However, constraints derived from pQCD computations and nuclear experiments such as PREX-II and CREX have minimal impact.

    astro-ph.HEgr-qcnucl-thPRD(2025)·30 citations
  14. 14

    Compact object of HESS J1731-347 and its implication on neutron star matter

    Prasanta Char · Bhaskar Biswas

    In this work, we investigate the impact of the possibility of a small, subsolar mass compact star, such as the recently reported central compact object of HESS J1731-347, on the equation of state (EOS) of neutron stars. We have used a hybrid approach to the nuclear EOS developed recently where the matter around nuclear saturation density is described by a parametric expansion in terms of nuclear empirical parameters and represented in an agnostic way at higher density using piecewise polytropes. We have incorporated the inputs provided by the latest neutron skin measurement experiments from PREX-II and CREX, simultaneous mass-radius measurements of pulsars PSR J0030+0451 and PSR J0740+6620, and the gravitational wave events GW170817 and GW190425. The main results of the study show the effect of HESS J1731-347 on the nuclear parameters and neutron star observables. Our analysis yields the slope of symmetry energy MeV, the radius of a star, km, and the maximum mass of a static star, within confidence interval, respectively.

    astro-ph.HEnucl-thPRD(2026)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE