Nuclear Theory
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 [1] arXiv:2406.12980 [pdf, html, other]

Title: Parity and timereversal violating nuclear forces with explicit $\Delta$excitationsComments: 11 pages, 4 figures, 1 tableSubjects: Nuclear Theory (nuclth)
We emphasize the usefulness of treating delta resonances as explicit degrees of freedom in applications of chiral effective field theory (EFT) to parityviolating and timereversalviolating (PVTV) nuclear interactions. Compared with the deltaless framework, the explicit inclusion of the delta isobar allows one to resum certain types of contributions to the PVTV twopion exchange two and threenucleon potentials without at the same time introducing any unknown parameters up to nexttonexttoleading order in the EFT expansion. We provide the corresponding expressions for the delta contributions in momentum and coordinate spaces and compare the convergence of the EFT expansion in both formulations.
 [2] arXiv:2406.13010 [pdf, html, other]

Title: IMSRG with flowing 3 body operators, and approximations thereofSubjects: Nuclear Theory (nuclth)
We explore the impact of retaining threebody operators within the inmedium similarity renormalization group (IMSRG), as well as various approximations schemes. After studying two toy problems, idential fermions with a contact interaction and the LipkinMeshkovGlick model, we employ the valencespace formulation of the IMSRG to investigate the even$A$ carbon isotopes with a chiral twobody potential. We find that retaining only those commutators expressions that scale as $N^7$ provides an excellent approximation of the full threebody treatment.
 [3] arXiv:2406.13055 [pdf, html, other]

Title: Selfconsistent strong screening applied to thermonuclear reactionsComments: 16 pages, 5 figures, typeset using LATEX default style in AASTeX631Subjects: Nuclear Theory (nuclth); Cosmology and Nongalactic Astrophysics (astroph.CO); Plasma Physics (physics.plasmph)
Selfconsistent strong plasma screening around light nuclei is implemented in the Big Bang nucleosynthesis (BBN) epoch to determine the shortrange screening potential, $e\phi(r)/T \geq 1$, relevant for thermonuclear reactions. We numerically solve the nonlinear PoissonBoltzmann equation incorporating FermiDirac statistics adopting a generalized screening mass to find the electric potential in the cosmic BBN electronpositron plasma for finitesized $^4$He nuclei as an example. Although the plasma follows Boltzmann statistics at large distances, FermiDirac statistics is necessary when work performed by ions on electrons is comparable to their rest mass energy. While strong screening effects are generally minor due to the high BBN temperatures, they can enhance the fusion rates of high$Z>2$ elements while leaving fusion rates of lower$Z\le 2$ elements relatively unaffected. Our results also reveal a pronounced spatial dependence of the strong screening potential near the nuclear surface. These findings about the electronpositron plasma's role refine BBN theory predictions and offer broader applications for studying weakly coupled plasmas in diverse cosmic and laboratory settings.
 [4] arXiv:2406.13417 [pdf, html, other]

Title: The study of $0\nu\beta\beta$ decay of $^{136}$Xe using nonclosure approach in nuclear shell modelComments: 10 pages, and 3 figuresSubjects: Nuclear Theory (nuclth)
In this investigation, we compute the nuclear matrix elements (NMEs) relevant to the light neutrinoexchange mechanism governing neutrinoless double beta ($0\nu\beta\beta$) decay in $^{136}$Xe. Our method is based on the nonclosure approach within the interacting nuclear shell model framework. This approach considers the genuine effects arising from the excitation energies of two hundred states for each spinparity of the intermediary nucleus $^{136}$Cs. All computations are performed using the effective shell model Hamiltonian GCN5082. To understand the impact of nuclear structure on $0\nu\beta\beta$ decay, we explore the dependence of the NME on various factors, including the number of intermediate states and their spinparity characteristics. We identify an optimal closure energy of approximately 3.7 MeV for the $0\nu\beta\beta$ decay of $^{136}$Xe that reproduces the nonclosure NME using the closure approach. The calculated total NME for the light neutrinoexchange $0\nu\beta\beta$ decay of $^{136}$Xe is 2.06 with the CDBonn shortrange correlation (SRC). These results can be valuable for future experimental investigations into the $0\nu\beta\beta$ decay of $^{136}$Xe.
 [5] arXiv:2406.13520 [pdf, html, other]

Title: Energy dependence of particle production in Au+Au collisions at $\sqrt{s_{\text{NN}}}$ = 7.7200 GeV using a multiphase transport modelSubjects: Nuclear Theory (nuclth); High Energy Physics  Experiment (hepex); High Energy Physics  Phenomenology (hepph)
In this study, we employ a multiphase transport (AMPT) model to understand the production of $\pi^{\pm}$, $K^{\pm}$, $p$, $\overline{p}$, $K^{0}_{s}$, $\Lambda$, $\bar{\Lambda}$, and $\phi$ in Au + Au collisions at $\sqrt{s_{NN}} = 7.7$, $27$, $39$, $62.4$, and $200$ GeV. We have studied the energy dependence of various bulk properties of the system such as transverse momentum ($p_T$) spectra, particle yields ($dN/dy$), mean transverse mass ($\langle m_T \rangle$), and antiparticle to particle ratios. Model calculations using both default and string melting versions of the AMPT with three distinct sets of initial conditions are compared to the data from the STAR experiment. In the case of $\pi^{\pm}$, $K^{\pm}$, $p$, and $\overline{p}$, we observe that the string melting version shows better agreement with data at higher energies, while the default version performs better at lower collision energies. However, for $K^{0}_{s}$, $\Lambda$, and $\phi$, it is observed that the default version is able to describe the data better at all energies. In addition, we have used the blastwave model to extract the kinetic freezeout properties, like the kinetic freezeout temperature and the radial flow velocity. We observe that these parameters are comparable with the data.
 [6] arXiv:2406.13717 [pdf, html, other]

Title: Beyond modified Urca: the nucleon width approximation for flavorchanging processes in dense matterComments: 6 pages, 6 figuresSubjects: Nuclear Theory (nuclth); High Energy Astrophysical Phenomena (astroph.HE); General Relativity and Quantum Cosmology (grqc); High Energy Physics  Phenomenology (hepph)
Flavorchanging charged current ("Urca") processes are of central importance in the astrophysics of neutron stars. Standard calculations approximate the Urca rate as the sum of two contributions, direct Urca and modified Urca. Attempts to make modified Urca calculations more accurate have been impeded by an unphysical divergence at the direct Urca threshold density. In this paper we describe a systematically improvable approach where, in the simplest approximation, instead of modified Urca we include an imaginary part of the nucleon mass (nucleon width). The total Urca rate is then obtained via a straightforward generalization of the direct Urca calculation, yielding results that agree with both direct and modified Urca at the densities where those approximations are valid. At low densities, we observe an enhancement of the rate by more than an order of magnitude, with important ramifications for neutron star cooling and other transport properties.
 [7] arXiv:2406.13863 [pdf, html, other]

Title: Revealing initial state properties through ultracentral symmetric heavyion collisionsComments: 32 pages, 10 figuresSubjects: Nuclear Theory (nuclth); Nuclear Experiment (nuclex)
Heavyion experiments provide a new opportunity to gain a deeper understanding of the structure of nuclei. To achieve this, it is crucial to identify observables under circumstances that are minimally affected by the process that leads to the initial state of heavyion collisions from nuclear wavefunction. In this study, we demonstrate that when assuming scaleinvariance, the effect of this stage on the initial energy or entropy density moments in ultracentral symmetric collisions is negligible for nucleon sizes of approximately 0.7 fm or larger for large nuclei. By borrowing cluster expansion method from statistical physics and using scaleinvariance assumption, we calculate the average ellipticity of initial density at the presence of shortrange correlation. We compare our calculations to Monte Carlo studies and assess the accuracy of various methods of shortrange correlation sampling. Additionally, we find that the isobar ratio can constrain the initial state parameters, in addition to deformation. Our study indicates that the isobar ratios in ultracentral collisions are especially sensitive to the fluctuation in the weight of the nuclei constituents and the twobody correlation among nucleons. This insight is crucial for drawing conclusions about nuclear deformations based on isobar ratios.
 [8] arXiv:2406.13899 [pdf, html, other]

Title: Faddeev calculations of lowenergy $\Lambda$deuteron scattering and momentum correlation functionComments: 10 pages, 7 figuresSubjects: Nuclear Theory (nuclth)
Faddeev calculations of lowenergy $\Lambda$deuteron elastic scattering are performed up to $E_{cm}=20$ MeV across the deuteron threshold. Phase shifts of the $s$wave with $J=1/2$ and $J=3/2$ are calculated using strangeness $S=1$ hyperonnucleon interactions in chiral effective field theory NLO13 and NLO19 parametrized by the J{ü}lichBonn group. Effective range parameters, such as a scattering length and an effective range, are determined through the calculated phase shifts. $\Lambda$deuteron momentum correlation functions are evaluated using the $\Lambda$deuteron relative wave function constructed from halfoffshell $t$matrices. They are compared with those evaluated using an approximate formula.
 [9] arXiv:2406.14463 [pdf, html, other]

Title: Hydrodynamiclike behaviour of glasmaComments: 19 pages, 5 figuresSubjects: Nuclear Theory (nuclth)
At the earliest stage of ultrarelativistic heavyion collisions the produced matter is a highly populated system of gluons called glasma which can be approximately described in terms of classical chromodynamic fields. Although the system's dynamics is governed by YangMills equations, glasma evolution is shown to strongly resemble hydrodynamic behaviour.
New submissions for Friday, 21 June 2024 (showing 9 of 9 entries )
 [10] arXiv:2406.12903 (crosslist from physics.insdet) [pdf, other]

Title: OpenSource Optimization of Hybrid MonteCarlo Methods for Fast Response Modeling of NaI(Tl) and HPGe Gamma DetectorsSubjects: Instrumentation and Detectors (physics.insdet); Nuclear Theory (nuclth)
Modeling the response of gamma detectors has long been a challenge within the nuclear community. Significant research has been conducted to digitally replicate instruments that can cost over $100,000 and are difficult to operate outside a laboratory setting. Subsequently, there have been multiple attempts to create codes that replicate the response of sodiumiodide and high purity germanium detectors for the purpose of deriving data related to gamma ray interaction with matter. While robust programs do exist, they are often subject to export controls and/or they are not intuitive to use. Through the use of the Hybrid MonteCarlo methods, MATLAB can be used to produce a fast firstorder response of various gamma ray detectors. The combination of a graphics user interface with a numerical based script allows for an opensource and intuitive code. When benchmarked with experimental data from Co60, Cs137, and Na22 the code can numerically calculate a response comparable to experimental and industry standard response codes. Through this code, it is shown that a savings in computational requirements and the inclusion of an intuitive user experience does not heavily compromise data when compared to other standard codes or experimental results. When the application is installed on a computer with 16 cores, the average time to simulate the benchmarked isotopes is 0.26 seconds and 1.63 seconds on a fourcore machine. The results indicate that simple gamma detectors can be modeled in an opensource format. The anticipation for the MATLAB application is to be a tool that can be easily accessible and provide datasets for use in an academic setting requiring the gamma ray detectors. Ultimately, providing evidence that Hybrid MonteCarlo codes in an opensource format can benefit the nuclear community.
 [11] arXiv:2406.13286 (crosslist from hepph) [pdf, html, other]

Title: Charm and Bottom Hadrons in Hot Hadronic MatterComments: 60 pages, 45 figures. Review article sent to Physics Reports journalSubjects: High Energy Physics  Phenomenology (hepph); Nuclear Experiment (nuclex); Nuclear Theory (nuclth)
Heavy quarks, and the hadrons containing them, are excellent probes of the QCD medium formed in highenergy heavyion collisions, as they provide direct information on the transport properties of the medium and how quarks colorneutralize into hadrons. Large theoretical and phenomenological efforts have been dedicated thus far to assess the diffusion of charm and bottom quarks in the quarkgluon plasma and their subsequent hadronization into heavyflavor (HF) hadrons. However, the fireball formed in heavyion collisions also features an extended hadronic phase, and therefore any quantitative analysis of experimental observables needs to account for rescattering of charm and bottom hadrons. This is further reinforced by the presence of a QCD crossover transition and the notion that the interaction strength is maximal in the vicinity of the pseudocritical temperature. We review existing approaches for evaluating the interactions of open HF hadrons in a hadronic heat bath and the pertinent results for scattering amplitudes, spectral functions and transport coefficients. While most of the work to date has focused on $D$ mesons, we also discuss excited states as well as HF baryons and the bottom sector. Both the HF hadrochemistry and bottom observables will play a key role in future experimental measurements. We also conduct a survey of transport calculations in heavyion collisions that have included effects of hadronic HF diffusion and assess their sensitivity to various observables.
 [12] arXiv:2406.13530 (crosslist from hepph) [pdf, html, other]

Title: Resonances in the quark modelComments: 17 pages, To appear in FewBody Systems, special issue on Critical StabilitySubjects: High Energy Physics  Phenomenology (hepph); Nuclear Theory (nuclth)
A discussion is presented of the estimates of the energy and width of resonances in constituent models, with focus on the tetraquark states containing heavy quarks.
 [13] arXiv:2406.13531 (crosslist from hepph) [pdf, html, other]

Title: LQCD constrained magnetic field dependent coupling constant in an effective modelComments: 8 pages, 4 figuresSubjects: High Energy Physics  Phenomenology (hepph); Nuclear Theory (nuclth)
A magnetic field dependent coupling constant $G(eB)$ is investigated in the twoflavor magnetized NJL model. Based on LQCD results of the neutral (charged) pion mass spectra at vanishing temperature and finite magnetic field, we determine the $G(eB)=G^0(eB)$ ($G(eB)=G^+(eB)$) in the NJL model. $G^0(eB)$ and $G^+(eB)$ are both nonmonotonic functions of magnetic fields, but they are different from each other. Furthermore, we calculate the pseudocritical temperatures $T_{pc}(eB)$ of chiral restoration phase transition with $G^0(eB)$ and $G^+(eB)$ in the magnetized NJL model, respectively. The resulting $T_{pc}(eB)$ are nonmonotonic functions of magnetic fields. In previous work, $G(eB)$ in the NJL model fitted from the chiral condensate or pseudocritical temperature of LQCD simulations is a decreasing function of magnetic field. It can not explain the saturation behavior of mass spectra of neutral pion and decreasing behavior of mass spectra of charged pion with strong magnetic field. We conclude that a magnetic field dependent coupling constant $G(eB)$ in the NJL model can not simultaneously explain the reduction of pseudocritical temperature of chiral restoration phase transition and the light meson mass spectra under external magnetic field.
 [14] arXiv:2406.13703 (crosslist from hepph) [pdf, html, other]

Title: Working group 1 summary: $V_{ud}$, $V_{us}$, $V_{cd}$, $V_{cs}$ and semileptonic/leptonic $D$ decaysComments: 12 pages, 3 figures; presented at the 12th Workshop on the CKM Unitarity Triangle, 1822 September 2023, Santiago de CompostelaSubjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Experiment (hepex); High Energy Physics  Lattice (heplat); Nuclear Experiment (nuclex); Nuclear Theory (nuclth)
We summarize the program of working group 1 at the 12th Workshop on the CKM Unitarity Triangle, whose main subjects covered $V_{ud}$, $V_{us}$, and firstrow unitarity as well as $V_{cd}$, $V_{cs}$, and (semi)leptonic $D$ decays.
 [15] arXiv:2406.13818 (crosslist from hepph) [pdf, html, other]

Title: Effective theory tower for $\mu\rightarrow e$ conversionComments: 60 pages, 7 figures, 7 tables, to be submitted to JHEPSubjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Experiment (hepex); Nuclear Theory (nuclth)
We present theoretical predictions for $\mu \rightarrow e$ conversion rates using a tower of effective field theories connecting the UV to nuclear physics scales. The interactions in nuclei are described using a recently developed nonrelativistic effective theory (NRET) that organizes contributions according to bound nucleon and muon velocities, $\vec{v}_N$ and $\vec{v}_\mu$, with $\vec{v}_N > \vec{v}_\mu$. To facilitate the topdown matching, we enlarge the set of Lorentz covariant nucleonlevel interactions mapped onto the NRET operators to include those mediated by tensor interactions, in addition to the scalar and vector interactions already considered previously, and then match NRET nonperturbatively onto the Weak Effective Theory (WET). At the scale $\mu \approx 2$ GeV WET is formulated in terms of $u$, $d$, $s$ quarks, gluons and photons as the light degrees of freedom, along with the flavorviolating leptonic current. We retain contributions from WET operators up to dimension 7, which requires the full set of 26 NRET operators. The results are encoded in the opensource Python and Mathematicabased software suite MuonBridge, which we make available to the theoretical and experimental communities interested in $\mu \rightarrow e$ conversion.
 [16] arXiv:2406.14158 (crosslist from condmat.quantgas) [pdf, html, other]

Title: Quantum vortices in fermionic superfluids: from ultracold atoms to neutron starsSubjects: Quantum Gases (condmat.quantgas); High Energy Astrophysical Phenomena (astroph.HE); Superconductivity (condmat.suprcon); Nuclear Theory (nuclth)
Superfluid dilute neutron matter and ultracold gas, close to the unitary regime, exhibit several similarities. Therefore, to a certain extent, fermionic ultracold gases may serve as emulators of dilute neutron matter, which forms the inner crust of neutron stars and is not directly accessed experimentally. Quantum vortices are one of the most significant properties of neutron superfluid, essential for comprehending neutron stars' dynamics. The structure and dynamics of quantum vortices as a function of pairing correlations' strength are being investigated experimentally and theoretically in ultracold gases. Certain aspects of these studies are relevant to neutron stars. We provide an overview of the characteristics of quantum vortices in swavetype fermionic and electrically neutral superfluids. The main focus is on the dynamics of fermionic vortices and their intrinsic structure.
 [17] arXiv:2406.14172 (crosslist from hepph) [pdf, html, other]

Title: Dynamics of Phase Transition in QuarkGluon Plasma Droplet Formation under Magnetic FieldSubjects: High Energy Physics  Phenomenology (hepph); Nuclear Theory (nuclth)
Preexisting density of states for a QuarkGluon Phase, based on ThomasFermi and Bethe mode, is expanded by incorporation of new variables. Results from recent study indicate that perturbations in the form of a finite nonzero chemical potential T, B, dynamic thermal masses M and of course Temperature T are indeed vital to fully comprehend the formation and dynamics of QGP. Simulations depict an overall increase in the stability of QGP in the paradigm of the statistical model. On the top of Free Energy, Entropy and heat capacity are calculated for the phase transition. The overall qualitative behavior, of entropy or Heat Capacity determines the order of phase transition of the QGP. Investigation of order of phase transition is carried out in this study through MonteCarlo based differential element, which ensures the inclusion of the randomness of the collisions at the particle colliders.
 [18] arXiv:2406.14466 (crosslist from astroph.HE) [pdf, html, other]

Title: The Radius of the High Mass Pulsar PSR J0740+6620 With 3.6 Years of NICER DataTuomo Salmi, Devarshi Choudhury, Yves Kini, Thomas E. Riley, Serena Vinciguerra, Anna L. Watts, Michael T. Wolff, Zaven Arzoumanian, Slavko Bogdanov, Deepto Chakrabarty, Keith Gendreau, Sebastien Guillot, Wynn C. G. Ho, Daniela Huppenkothen, Renee M. Ludlam, Sharon M. Morsink, Paul S. RayComments: 17 pages, 9 figures (2 of which are figure sets), 2 tables, accepted for publication in ApJSubjects: High Energy Astrophysical Phenomena (astroph.HE); Nuclear Theory (nuclth)
We report an updated analysis of the radius, mass, and heated surface regions of the massive pulsar PSR J0740+6620 using NICER data from 2018 September 21 to 2022 April 21, a substantial increase in data set size compared to previous analyses. Using a tight mass prior from radio timing measurements and jointly modeling the new NICER data with XMMNewton data, the inferred equatorial radius and gravitational mass are $12.49_{0.88}^{+1.28}$ km and $2.073_{0.069}^{+0.069}$ $M_\odot$ respectively, each reported as the posterior credible interval bounded by the $16\,\%$ and $84\,\%$ quantiles, with an estimated systematic error $\lesssim 0.1$ km. This result was obtained using the best computationally feasible sampler settings providing a strong radius lower limit but a slightly more uncertain radius upper limit. The inferred radius interval is also close to the $R=12.76_{1.02}^{+1.49}$ km obtained by Dittmann et al. 2024, when they require the radius to be less than $16$ km as we do. The results continue to disfavor very soft equations of state for dense matter, with $R<11.15$ km for this high mass pulsar excluded at the $95\,\%$ probability. The results do not depend significantly on the assumed crosscalibration uncertainty between NICER and XMMNewton. Using simulated data that resemble the actual observations, we also show that our pipeline is capable of recovering parameters for the inferred models reported in this paper.
 [19] arXiv:2406.14467 (crosslist from astroph.HE) [pdf, html, other]

Title: A More Precise Measurement of the Radius of PSR J0740+6620 Using Updated NICER DataAlexander J. Dittmann, M. Coleman Miller, Frederick K. Lamb, Isiah Holt, Cecilia Chirenti, Michael T. Wolff, Slavko Bogdanov, Sebastien Guillot, Wynn C. G. Ho, Sharon M. Morsink, Zaven Arzoumanian, Keith C. GendreauComments: 18 pages, 8 figures, +appendices. Accepted in ApJSubjects: High Energy Astrophysical Phenomena (astroph.HE); General Relativity and Quantum Cosmology (grqc); Nuclear Experiment (nuclex); Nuclear Theory (nuclth)
PSR J0740+6620 is the neutron star with the highest precisely determined mass, inferred from radio observations to be $2.08\pm0.07\,\rm M_\odot$. Measurements of its radius therefore hold promise to constrain the properties of the cold, catalyzed, highdensity matter in neutron star cores. Previously, Miller et al. (2021) and Riley et al. (2021) reported measurements of the radius of PSR J0740+6620 based on Neutron Star Interior Composition Explorer (NICER) observations accumulated through 17 April 2020, and an exploratory analysis utilizing NICER background estimates and a data set accumulated through 28 December 2021 was presented in Salmi et al. (2022). Here we report an updated radius measurement, derived by fitting models of Xray emission from the neutron star surface to NICER data accumulated through 21 April 2022, totaling $\sim1.1$ Ms additional exposure compared to the data set analyzed in Miller et al. (2021) and Riley et al. (2021), and to data from Xray MultiMirror (XMMNewton) observations. We find that the equatorial circumferential radius of PSR J0740+6620 is $12.92_{1.13}^{+2.09}$ km (68% credibility), a fractional uncertainty $\sim83\%$ the width of that reported in Miller et al. (2021), in line with statistical expectations given the additional data. If we were to require the radius to be less than 16 km, as was done in Salmi et al. (2024), then our 68% credible region would become $R=12.76^{+1.49}_{1.02}$ km, which is close to the headline result of Salmi et al. (2024). Our updated measurements, along with other laboratory and astrophysical constraints, imply a slightly softer equation of state than that inferred from our previous measurements.
Cross submissions for Friday, 21 June 2024 (showing 10 of 10 entries )
 [20] arXiv:2105.13481 (replaced) [pdf, html, other]

Title: Hyperon Polarization from the Vortical Fluid in Low Energy Nuclear CollisionsComments: 5 pages, 4 figures, new results for hyperon local polarization are addedJournalref: Phys. Rev. C 104, 041902 (2021)Subjects: Nuclear Theory (nuclth); High Energy Physics  Phenomenology (hepph); Nuclear Experiment (nuclex)
In 2017, STAR Collaboration reported the measurements of hyperon global polarization in heavy ion collisions, suggesting the subatomic fireball fluid created in these collisions as the most vortical fluid. There remains the interesting question: at which beam energy the truly most vortical fluid will be located. In this work we perform a systematic study on the beam energy dependence of hyperon global polarization phenomenon, especially in the interesting $\hat{O}(1\sim 10)\ \rm GeV$ region. We find a nonmonotonic trend, with the global polarization to first increase and then decrease when beam energy is lowered from $27~\rm GeV$ down to $3~\rm GeV$. The maximum polarization signal has been identified around $\sqrt{s_{NN}} = 7.7~\rm GeV$, where the heavy ion collisions presumably create the most vortical fluid. Detailed experimental measurements in the $\hat{O}(1\sim 10)\ \rm GeV$ beam energy region are expected to test the prediction very soon.
 [21] arXiv:2211.03968 (replaced) [pdf, html, other]

Title: Electromagnetic fields in ultraperipheral relativistic heavyion collisionsComments: 5 pages, 4 figures, published version at NSTJournalref: Nuclear Science and Techniques, 35, 20 (2024)Subjects: Nuclear Theory (nuclth); Nuclear Experiment (nuclex)
Ultraperipheral heavyion collisions (UPCs) offer unique opportunities to study processes under strong electromagnetic fields. In these collisions, highly charged fastmoving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes. The exchange of photons can induce photonuclear and twophoton interactions, and excite ions. This excitation of the ions results in Coulomb dissociation with the emission of photons, neutrons, and other particles. Additionally, the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions. Consequently, the two colliding ions experienced an electromagnetic force that pushed them in opposite directions, causing a backtoback correlation in the emitted neutrons. Using a Monte Carlo simulation, we qualitatively demonstrated that the above electromagnetic effect is large enough to be observed in UPCs, which would provide a clear means to study strong electromagnetic fields and their effects.
 [22] arXiv:2305.03703 (replaced) [pdf, html, other]

Title: Impact of the preequilibrium phase for the determination of nuclear geometry in highenergy isobar collisionsComments: v2: 26 pages, 12 figures. Extended discussion and new resultsSubjects: Nuclear Theory (nuclth); High Energy Physics  Phenomenology (hepph)
Ultrarelativistic isobar collisions have been proposed as a useful tool to investigate nuclear structure. These systems are not created in equilibrium, rather undergo a prethermalization phase. In this phase, some of the initial structure information may be lost and additional effects introduced. The objective of this paper is to study this possibility in the extreme case of a "freestreaming" preequilibrium phase. We do this by computing estimators for ratios of various measured (or measurable) quantities (elliptic and triangular flows, mean transverse momentum and associated cumulants, correlators between elliptic or triangular flows and mean transverse momentum, symmetric cumulant and twoplane correlator) and study their sensitivity to the duration of the freestreaming phase. We find that the correlators between elliptic or triangular flows and mean transverse momentum, the socalled $\rho_2$ and $\rho_3$, are indeed sensitive to the duration of the freestreaming phase and that the normalized symmetric cumulant, $\epsilon NSC(2,3)$ might also depend on this duration.
 [23] arXiv:2306.03327 (replaced) [pdf, html, other]

Title: Superfluid extension of the selfconsistent timedependent band theory for neutron star matter: Antientrainment versus superfluid effects in the slab phaseComments: 21 pages, 11 figures, 4 tables. v4  Version accepted for publication in Physical Review C, selected as an Editors' SuggestionJournalref: Phys. Rev. C 109, 065804 (2024)Subjects: Nuclear Theory (nuclth); High Energy Astrophysical Phenomena (astroph.HE); Quantum Gases (condmat.quantgas)
Background: The inner crust of neutron stars consists of a Coulomb lattice of neutronrich nuclei, immersed in a sea of superfluid neutrons with background relativistic electron gas. A proper quantum mechanical treatment for such a system under a periodic potential is the band theory of solids. The effect of band structure on the effective mass of dripped neutrons, the socalled \textit{entrainment effect}, is currently in a debatable situation, and it has been highly desired to develop a nuclear band theory taking into account neutron superfluidity in a fully selfconsistent manner.
Purpose: The main purpose of the present work is twofold: 1) to develop a formalism of the timedependent selfconsistent band theory, taking full account of nuclear superfluidity, based on timedependent density functional theory (TDDFT) extended for superfluid systems, and 2) to quantify the effects of band structure and superfluidity on crustal properties, applying the formalism to the slab phase of nuclear matter in the $\beta$ equilibrium.
Results: Static calculations have been performed for a range of baryon (nucleon) number density ($n_b=0.040.07$ fm$^{3}$) under the $\beta$equilibrium condition with and without superfluidity, for various interslab spacings. From a dynamic response to an external potential, we extract the collective mass of a slab and that of protons immersed in neutron superfluid. From the results, we find that the collective mass of a slab is substantially reduced by 57.582.5\% for $n_b=0.040.07$ fm$^{3}$, which corresponds to an enhancement of conduction neutron number density and, thus, to a reduction of the neutron effective mass, which we call the antientrainment effect. We discuss novel phenomena associated with superfluidity, quasiparticle resonances in the inner crust, which are absent in normal systems.
*shortened due to the arXiv word limit.  [24] arXiv:2307.13132 (replaced) [pdf, html, other]

Title: Neck Rupture and Scission Neutrons in Nuclear FissionComments: 5 pages, 4 figuresJournalref: Phys. Rev. Lett. 132, 242501 (2024)Subjects: Nuclear Theory (nuclth)
Just before a nucleus fissions a neck is formed between the emerging fission fragments. It is widely accepted that this neck undergoes a rather violent rupture, despite no direct experimental evidence, and only a few contentious theoretical treatments of this fission stage were ever performed in the more than eight decades since nuclear fission was experimentally observed by Hahn and Strassmann and described by Meitner and Frisch in 1939. In the same year, Bohr and Wheeler conjectured that the fission of the nuclear liquid drop would likely be accompanied by the rapid formation of tiny droplets, later identified with either scission neutrons or other ternary fission fragments, a process which has not yet been discussed in a fully quantum manybody framework. The main difficulty in addressing both of these stages of nuclear fission is both are highly nonequilibrium processes. Here we will present the first fully microscopic characterization of the scission mechanism, along with the spectrum and the spatial distribution of scission neutrons, and some upper limit estimates for the emission of charged particles.
 [25] arXiv:2308.03356 (replaced) [pdf, html, other]

Title: Relativistic modelfree prediction for neutrinoless double beta decay at leading orderComments: 8 pages, 4 figuresJournalref: Phys. Lett. B 855 (2024) 138782Subjects: Nuclear Theory (nuclth); High Energy Physics  Lattice (heplat); High Energy Physics  Phenomenology (hepph)
Starting from a manifestly Lorentzinvariant chiral Lagrangian, we present a modelfree prediction for the transition amplitude of the process $nn\rightarrow pp e^e^$ induced by light Majorana neutrinos, which is a key process of the neutrinoless double beta decay ($0\nu\beta\beta$) in heavy nuclei employed in largescale searches. Contrary to the nonrelativistic case, we show that the transition amplitude can be renormalized at leading order without any uncertain contact operators. The predicted amplitude defines a stringent benchmark for the previous estimation with modeldependent inputs, and greatly reduces the uncertainty of $0\nu\beta\beta$ transition operator in the calculations of nuclear matrix elements. Generalizations of the present framework could also help to address the uncertainties in $0\nu\beta\beta$ decay induced by other mechanisms. In addition, the present work motivates a relativistic {\it ab initio} calculation of $0\nu\beta\beta$ decay in light and mediummass nuclei.
 [26] arXiv:2401.16995 (replaced) [pdf, html, other]

Title: Compton Scattering on 4He with Nuclear One and TwoBody DensitiesHarald W. Griesshammer (George Washington U.), Junjie Liao (George Washington U.), Judith A. McGovern (U. of Manchester), Andreas Nogga (FZ Jülich), Daniel R. Phillips (Ohio U.)Comments: 38 pages LaTeX2e (pdflatex) including 13 figures as 14 .pdf files using includegraphics. Minor grammatical/typographical changes, figures 3, 4 and 7 typographically corrected without changes of substance. Text and figureidentical to published versionSubjects: Nuclear Theory (nuclth); Nuclear Experiment (nuclex)
We present the first \emph{ab initio} calculation of elastic Compton scattering from 4He. It is carried out to $\mathcal{O}(e^2 \delta^3)$ [N3LO] in the $\delta$ expansion of $\chi$EFT. At this order and for this target, the only free parameters are the scalarisoscalar electric and magnetic dipole polarisabilities of the nucleon. Adopting current values for these yields a parameterfree prediction. This compares favourably with the world data from HI$\gamma$S, Illinois and Lund for photon energies $50\;\mathrm{MeV}\lesssim\omega\lesssim120\;\mathrm{MeV}$ within our theoretical uncertainties of $\pm10\%$. We predict a cross section up to 7 times that for deuterium. As in 3He, this emphasises and tests the key role of mesonexchange currents between np pairs in Compton scattering on light nuclei. We assess the sensitivity of the cross section and beam asymmetry to the nucleon polarisabilities, providing clear guidance to future experiments seeking to further constrain them. The calculation becomes tractable by use of the Transition Density Method. The one and twobody densities generated from 5 chiral potentials and the AV18$+$UIX potential are available using the python package provided at \url{this https URL}.
 [27] arXiv:2405.12243 (replaced) [pdf, html, other]

Title: The KohnLuttinger Effect in Dense Matter and its Implications for Neutron StarsComments: 34 pages, 11 figuresSubjects: Nuclear Theory (nuclth); High Energy Astrophysical Phenomena (astroph.HE); Superconductivity (condmat.suprcon)
Repulsive shortrange interactions can induce pwave attraction between fermions in dense matter and lead to Cooper pairing at the Fermi surface. We investigate this phenomenon, wellknown as the KohnLuttinger effect in condensed matter physics, in dense matter with strong shortrange repulsive interactions. We find that repulsive interactions required to stabilize massive neutron stars can induce pwave pairing in neutron and quark matter. When massive vector bosons mediate the interaction between fermions, the induced interaction favors Cooper pairing in the 3P2 channel. For the typical strength of the interaction favored by massive neutron stars, the associated pairing gaps in neutrons can be in the range of 10 keV to 10 MeV. Strong and attractive spinorbit and tensor forces between neutrons can result in repulsive induced interactions that greatly suppress the 3P2 pairing gap in neutron matter. In quark matter, the induced interaction is too small to result in pairing gaps of phenomenological relevance.
 [28] arXiv:2209.14309 (replaced) [pdf, html, other]

Title: Symmetry energy in holographic QCDComments: LaTeX: 29 pages, 5 figures; V2: extended version; V3: comments, references and appendices C through E addedJournalref: SciPost Phys. 16, 156 (2024)Subjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Theory (hepth); Nuclear Theory (nuclth)
We study the symmetry energy (SE), an important quantity in nuclear physics, in the WittenSakaiSugimoto model and in a much simpler hardwall model of holographic QCD. The SE is the energy contribution to the nucleus due to having an unequal number of neutrons and protons. Using a homogeneous Ansatz representing smeared instantons and quantizing their isospin, we extract the SE and the proton fraction assuming charge neutrality and betaequilibrium, using quantization of the isospin zeromode. We also show the equivalence between our method adapted from solitons and the usual way of the isospin controlled by a chemical potential at the holographic boundary. We find that the SE can be well described in the WSS model if we allow for a larger 't Hooft coupling and lower KaluzaKlein scale than is normally used in phenomenological fits.
 [29] arXiv:2312.02278 (replaced) [pdf, html, other]

Title: Learning PDFs through Interpretable Latent Representations in Mellin SpaceComments: 22 pages, 11 figures; updated link to public code, this https URLSubjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Lattice (heplat); Nuclear Theory (nuclth)
Representing the parton distribution functions (PDFs) of the proton and other hadrons through flexible, highfidelity parametrizations has been a longstanding goal of particle physics phenomenology. This is particularly true since the chosen parametrization methodology can play an influential role in the ultimate PDF uncertainties as extracted in QCD global analyses; these, in turn, are often determinative of the reach of experiments at the LHC and other facilities to nonstandard physics, including at large $x$, where parametrization effects can be significant. In this study, we explore a series of encoderdecoder machinelearning (ML) models with various neuralnetwork topologies as efficient means of reconstructing PDFs from meaningful information stored in an interpretable latent space. Given recent effort to pioneer synergies between QCD analyses and latticegauge calculations, we formulate a latent representation based on the behavior of PDFs in Mellin space, i.e., their integrated moments, and test the ability of various models to decode PDFs from this information faithfully. We introduce a numerical package, $\texttt{PDFdecoder}$, which implements several encoderdecoder models to reconstruct PDFs with high fidelity and use this tool to explore strengths and pitfalls of neuralnetwork approaches to PDF parametrization. We additionally dissect patterns of learned correlations between encoded Mellin moments and reconstructed PDFs which suggest opportunities for further improvements to MLbased approaches to PDF parametrizations and uncertainty quantification.
 [30] arXiv:2401.14917 (replaced) [pdf, html, other]

Title: Direct WIMP detection rates for transitions in isomeric nucleiSubjects: High Energy Physics  Phenomenology (hepph); Nuclear Experiment (nuclex); Nuclear Theory (nuclth)
The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study WIMP induced transitions from isomeric nuclear states for two possible isomeric candidates: $\rm^{180}Ta$ and $\rm^{166}Ho$. The experimental setup, which can measure the possible decay of $\rm^{180}Ta$ induced by WIMPs, was proposed. The corresponding estimates of the halflife of $\rm^{180}Ta$ are given in the sense that the WIMPnucleon interaction can be interpreted as ordinary radioactive decay.
 [31] arXiv:2402.15628 (replaced) [pdf, html, other]

Title: Toward extracting the scattering phase shift from integrated correlation functions II: a relativistic lattice field theory modelComments: match to PRD accepted versionSubjects: High Energy Physics  Lattice (heplat); High Energy Physics  Phenomenology (hepph); Nuclear Theory (nuclth)
In present work, a relativistic relation that connects the difference of interacting and noninteracting integrated twoparticle correlation functions in finite volume to infinite volume scattering phase shift through an integral is derived. We show that the difference of integrated finite volume correlation functions converge rapidly to its infinite volume limit as the size of periodic box is increased. The fast convergence of our proposed formalism is illustrated by analytic solutions of a contact interaction model, the perturbation theory calculation, and also Monte Carlo simulation of a complex $\phi^4$ lattice field theory model.
 [32] arXiv:2403.06133 (replaced) [pdf, html, other]

Title: Transverse polarization of Lambda hyperons in hadronic collisionsComments: 13 pages, 15 figuresSubjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Experiment (hepex); Nuclear Theory (nuclth)
The transverse polarization of $\Lambda$ hyperon within reconstructed jets in hadronic collisions offers a complementary platform to probe the polarized fragmentation function $D_{1T}^\perp$. We illustrate that by performing a global analysis of the transverse polarization of $\Lambda$ hyperons produced in different kinematic regions and in different hadronic collisions, such as $pp$, $p\bar p$, $pA$, and $\gamma A$ collisions, we can pin down the flavor dependence of $D_{1T}^\perp$ which has been poorly constrained. Besides the single inclusive jet production, the $\gamma/Z^0$boson associated jet production supplements with more capability in removing ambiguities in the flavor dependence of $D_{1T}^\perp$.
 [33] arXiv:2405.04681 (replaced) [pdf, html, other]

Title: Onset of scaling violation in pion and kaon elastic electromagnetic form factorsComments: 8 pages, 5 figures, 1 tableSubjects: High Energy Physics  Phenomenology (hepph); High Energy Physics  Experiment (hepex); High Energy Physics  Lattice (heplat); Nuclear Experiment (nuclex); Nuclear Theory (nuclth)
Using a symmetrypreserving truncation of the quantum field equations describing hadron properties, parameterfree predictions are delivered for pion and kaon elastic electromagnetic form factors, $F_{P=\pi,K}$, thereby unifying them with kindred results for nucleon elastic electromagnetic form factors. Regarding positivecharge states, the analysis stresses that the presence of scaling violations in QCD entails that $Q^2 F_P(Q^2)$ should exhibit a single maximum on $Q^2>0$. Locating such a maximum is both necessary and sufficient to establish the existence of scaling violations. The study predicts that, for charged $\pi$, $K$ mesons, the $Q^2 F_P(Q^2)$ maximum lies in the neighbourhood $Q^2 \simeq 5\,$GeV$^2$. Foreseeable experiments will test these predictions and, providing their $Q^2$ reach meets expectations, potentially also provide details on the momentum dependence of meson form factor scaling violation.
 [34] arXiv:2406.01754 (replaced) [pdf, html, other]

Title: Validating Automated Resonance Evaluation with Synthetic DataOleksii Zivenko, Noah A. W. Walton, William Fritsch, Jacob Forbes, Amanda M. Lewis, Aaron Clark, Jesse M. Brown, Vladimir SobesSubjects: Computational Physics (physics.compph); Nuclear Experiment (nuclex); Nuclear Theory (nuclth); Medical Physics (physics.medph)
The integrity and precision of nuclear data are crucial for a broad spectrum of applications, from national security and nuclear reactor design to medical diagnostics, where the associated uncertainties can significantly impact outcomes. A substantial portion of uncertainty in nuclear data originates from the subjective biases in the evaluation process, a crucial phase in the nuclear data production pipeline. Recent advancements indicate that automation of certain routines can mitigate these biases, thereby standardizing the evaluation process, reducing uncertainty and enhancing reproducibility. This article contributes to developing a framework for automated evaluation techniques testing, emphasizing automated fitting methods that do not require the user to provide any prior information. This approach simplifies the process and reduces the manual effort needed in the initial evaluation stage. It highlights the capability of the framework to validate and optimize subroutines, targeting the performance analysis and optimization of the fitting procedure using highfidelity synthetic data (labeled experimental data) and the concept of a fully controlled computational experiment. An error metric is introduced to provide a clear and intuitive measure of the fitting quality by quantifying the accuracy and performance across the specified energy. This metric sets a scale for comparison and optimization of routines or hyperparameter selection, improving the entire evaluation process methodology and increasing reproducibility and objectivity.
 [35] arXiv:2406.11372 (replaced) [pdf, html, other]

Title: Universal spectrum of non efimovian threebody resonances at finite scattering lengthComments: In this new version, a typo on the number page 4, last line, first column is correctedSubjects: Quantum Gases (condmat.quantgas); Nuclear Theory (nuclth)
Using exact solutions of the threebody problem, the spectrum of non efimovian threebody resonances for two identical particles interacting with another one is derived in the regime of large but finite scattering length. The universality of the problem is depicted by using a contact model in the generalized effective range approximation, parameterized by two threebody parameters and the scattering length.