Nuclear Theory·nucl-th

Wednesday·October 2, 2024

19 papers—7 primary·12 cross-listed

08
Entanglement entropy of a color flux tube in (2+1)D Yang-Mills theory
Rocco Amorosso🇺🇸 · Sergey Syritsyn🇺🇸 · Raju Venugopalan🇺🇸
We construct a novel flux tube entanglement entropy (FTE $^{2}$ ), defined as the excess entanglement entropy relative to the vacuum of a region of color flux stretching between a heavy quark-anti-quark pair in pure gauge Yang-Mills theory. We show that FTE $^{2}$ can be expressed in terms of correlators of Polyakov loops, is manifestly gauge-invariant, and therefore free of the ambiguities in computations of the entanglement entropy in gauge theories related to the choice of the center algebra. Employing the replica trick, we compute FTE $^{2}$ for $S U (2)$ Yang-Mills theory in (2+1)D and demonstrate that it is finite in the continuum limit. We explore the properties of FTE $^{2}$ for a half-slab geometry, which allows us to vary the width and location of the slab, and the extent to which the slab cross-cuts the color flux tube. Following the intuition provided by computations of FTE $^{2}$ in (1+1)D, and in a thin string model, we examine the extent to which our FTE $^{2}$ results can be interpreted as the sum of an internal color entropy and a vibrational entropy corresponding to the transverse excitations of the string.
↳ hep-lathep-phhep-thnucl-thJHEP(2024)·22 citations
09
Accessing universal relations of binary neutron star waveforms in massive scalar-tensor theory
Alan Tsz-Lok Lam🇩🇪 · Yong Gao🇩🇪 · Hao-Jui Kuan🇩🇪 · Masaru Shibata🇩🇪 · Karim Van Aelst🇩🇪 · Kenta Kiuchi🇩🇪
We investigate how the quasi-universal relations connecting tidal deformability with gravitational waveform characteristics and/or properties of individual neutron stars that were proposed in the literature within general relativity would be influenced in the massive Damour-Esposito-Farese-type scalar-tensor gravity. For this purpose, we systematically perform numerical relativity simulations of ~120 binary neutron star mergers with varying scalar coupling constants. Although only three neutron-star equations of state are adopted, a clear breach of universality can be observed in the data sets. In addition to presenting difficulties in constructing quasi-universal relations in alternative gravity theories, we also briefly compare the impacts of non-general-relativity physics on the waveform features and those due to the first order or cross-over quantum chromodynamical phase transition.
↳ astro-ph.HEgr-qcnucl-thPRL(2025)·14 citations
10
Probing fermionic asymmetric dark matter cores using global neutron star properties
Nathan Rutherford🇺🇸 · Chanda Prescod-Weinstein🇺🇸 · Anna Watts🇳🇱
It is possible for asymmetric dark matter (ADM) to accumulate in neutron star interiors and affect their global properties. Considering the effects of this accumulation, neutron star mass-radius measurements can deliver new insights into the cold dense matter equation of state (EoS). In this paper, we employ Bayesian parameter estimation using real and synthetic neutron star mass-radius data to infer constraints on the combined baryonic matter and fermionic ADM EoS, where the fermionic ADM forms a core in the neutron star interior. Using currently available mass-radius data, we find that the lower bound of the ratio between ADM effective self-repulsion strength ( $g_{χ} / m_{ϕ}$ ) and particle mass ( $m_{χ}$ ) can be constrained at the 68\% (95\%) credible level to $1 0^{- 6.59}$ ( $1 0^{- 7.77}$ ). We also find that, if neutron star mass-radius measurement uncertainties are reduced to the 2\% level, the constraints on the lower bound of the ratio of $g_{χ} / m_{ϕ}$ to $m_{χ}$ can be improved to $1 0^{- 6.49}$ and $1 0^{- 7.68}$ at the 68\% and 95\% credible levels, respectively. However, all other combinations, of $m_{χ}$ , $g_{χ}$ , and the ADM mass-fraction, $F_{χ}$ , (i.e., the ratio of the gravitational ADM mass to the gravitational mass of the neutron star) are unconstrained. Furthermore, in the pressure-energy density and mass-radius planes, the inferences which include the possibility of fermionic ADM cores are nearly identical with the inferences that neglect fermionic ADM for $F_{χ} \leq 1.7%$ and neutron star mass-radius uncertainties $\geq 2%$ . Therefore, we find that neutron star mass-radius measurements can constrain the ratio of $g_{χ} / m_{ϕ}$ to $m_{χ}$ and that neutron stars with ADM are indistinguishable from purely baryonic stars. This implies that neutron stars with ADM are equally as consistent with the available mass-radius data as neutron stars without ADM.
↳ astro-ph.HEastro-ph.SRhep-phnucl-thPRD(2025)·29 citations
11
Unlocking higher-order moments of parton distribution functions from lattice QCD
Andrea Shindler🇩🇪
We present a new method to calculate moments of parton distribution functions of any order with lattice QCD computations. This method leverages the gradient flow for fermion and gauge fields. The flowed matrix elements of twist-2 operators renormalize multiplicatively, and the matching with physical matrix elements is achieved through the use of continuum symmetries. We derive the matching coefficients at one-loop in perturbation theory for moments of any order in the flavor non-singlet case and provide specific examples of operators suitable for lattice QCD computations. The multiplicative renormalization and matching are independent of the choice of Lorentz indices, allowing the use of temporal indices for twist-2 operators of any dimension. This approach should then also significantly enhance the signal-to-noise ratio in the computation of moments.
↳ hep-lathep-phnucl-thPoS(2025)·1 citation
12
Precise Mass Measurement of the Longest Odd-Odd Chain of \boldmath $1^{+}$ Ground States
B. Liu🇺🇸 · M. Brodeur🇺🇸 · J.A. Clark🇺🇸 · I. Dedes🇵🇱 · J. Dudek🇫🇷 · F. G. Kondev🇺🇸 · D. Ray🇺🇸 · G. Savard🇺🇸 · A.A. Valverde🇺🇸 · A. Baran · D.P. Burdette🇺🇸 · A.M. Houff🇺🇸 and 5 other authors
Precise mass measurements of the ground and isomeric states of the odd-odd $^{108, 110, 112, 114, 116}$ Rh were performed using the Canadian Penning Trap at Argonne National Laboratory, showing good agreement with recent JYFLTRAP measurements. A new possible isomeric state of $^{114}$ Rh was also observed. These isotopes are part of the longest odd-odd chain of identical ground-state spin-parity assignment of 1 $^{+}$ , spanning $^{104 - 118}$ Rh, despite being in a region of deformation. Realistic phenomenological mean-field calculations using ``universal'' Wood-Saxon Hamiltonian were performed, which explained this phenomenon for the first time. In addition, multi-quasiparticle blocking calculations were performed to study the configuration of low-lying states in the odd-odd Rh nuclei, elucidating anomalous isomeric yield ratio observed for $^{114}$ Rh.
↳ nucl-exnucl-thPRC(2025)·7 citations
13
Low- $Q^{2}$ nucleon structure from an infrared-safe evolution scheme
Rong Wang🇨🇳
The low- $Q^{2}$ nucleon structure is given with a simple nonperturbative input of three valence quarks and an all-order infrared-safe evolution scheme, showing some consistences with the experimental data. The resonance peaks in the experimental data of $F_{2}$ structure function are found to be modulated by the valence quark distributions. With little sea quark distribution at low $Q^{2}$ the valence-quark bump is clearly shown in the structure function. The three valence quark distributions at the hadronic scale is found to be the dominant origin of the PDFs at the hard scales. The high-twist corrections are needed to explain the sizeable discrepancy between the theory and the experimental measurements at low $Q^{2}$ . The infrared-safe evolution scheme is a powerful tool for connecting the nucleon structures in the nonperturbative and perturbative regions.
↳ hep-phnucl-th1 citation
14
Molecular states with charm: insights from vacuum and finite-temperature analyses
Juan M. Torres-Rincon🇪🇸
This contribution to the SQM2024 conference covers the molecular hypothesis for the internal structure of some open and hidden charm states. The use of effective theories that incorporate heavy-quark spin symmetry, combined with unitarization techniques, has provided strong evidences supporting this interpretation. In the heavy-light sector, we discuss the double pole structure of the $D_{0}^{*} (2300)$ and the generation of the $D_{s 0}^{*} (2317)$ . In the hidden charm sector, we focus on the exotic $X (3872)$ and its heavy-quark partner, the $X (4014)$ . Furthermore, we emphasize the benefits of femtoscopic measurements in $p + p$ collisions to establish the nature of these states, as well as the potential role of temperature to discern their internal structure.
↳ hep-phnucl-thEPJ Web Conf.(2025)·1 citation
15
Two-dimensional bosonic droplets in a harmonic trap
Fabian Brauneis · Artem G. Volosniev · Hans-Werner Hammer
We investigate a system of bosons in a two-dimensional harmonic trap. In the limit of strong attractive interactions, the bosons make a droplet insensitive to external confinement. For weak interactions, in contrast, the ground state is given by the harmonic trap. In this work, we conduct a variational study of the transition between these two limits. We find that this transition occurs abruptly at the critical interaction strength whose value is universal if scaled appropriately with the number of particles. To connect the abrupt change in the properties of the system to the classical description of phase transitions, we analyze the static response of the Bose gas related to the isothermal compressibility. Finally, we perform numerically exact calculations for a few particles to demonstrate the effects of finite range interactions on this transition. We conclude that finite range effects wash out the point of transition.
↳ cond-mat.quant-gasnucl-thPRA(2025)·3 citations
16
Electric dipole polarizability of $^{58}$ Ni
I. Brandherm · F. Bonaiti · P. von Neumann-Cosel · S. Bacca · G. Colò · G.R. Jansen · Z.Z. Li · H. Matsubara · Y.F. Niu · P.-G. Reinhard · A. Richter · X. Roca-Maza · A. Tamii
The electric dipole strength distribution in $^{58}$ Ni between 6 and 20 MeV has been determined from proton inelastic scattering experiments at very forward angles at RCNP, Osaka. The experimental data are rather well reproduced by quasiparticle random-phase approximation calculations including vibration coupling, despite a mild dependence on the adopted Skyrme interaction. They allow an estimate of the experimentally inaccessible high-energy contribution above 20 MeV, leading to an electric dipole polarizability $α_{D} (^{58} Ni) = 3.48 (31)$ fm $^{3}$ . This serves as a test case for recent extensions of coupled-cluster calculations with chiral effective field theory interactions to nuclei with two nucleons on top of a closed-shell system.
↳ nucl-exnucl-thPRC(2025)·10 citations
17
Quantum Closures for Neutrino Moment Transport
James P. Kneller🇺🇸 · Julien Froustey🇺🇸 · Evan B. Grohs🇺🇸 · Francois Foucart🇬🇧 · Gail C. McLaughlin🇺🇸 · Sherwood Richers🇺🇸
A computationally efficient method for calculating the transport of neutrino flavor in simulations is to use angular moments of the neutrino one-body reduced density matrix, i.e., `quantum moments'. As with any moment-based radiation transport method, a closure is needed if the infinite tower of moment evolution equations is truncated. We derive a general parameterization of a quantum closure and the limits the parameters must satisfy in order for the closure to be physical. We then derive from multi-angle calculations the evolution of the closure parameters in two test cases which we then progressively insert into a moment evolution code and show how the parameters affect the moment results until the full multi-angle results are reproduced. This parameterization paves the way to setting prescriptions for genuine quantum closures adapted to neutrino transport in a range of situations.
↳ hep-phastro-ph.HEnucl-thPRD(2025)·13 citations
18
Recent $J / ψ$ measurements at the PHENIX experiment
Xuan Li (on behalf of the PHENIX collaboration)🇺🇸
Quarkonium is an ideal probe to explore the properties of quantum chromodynamics (QCD). Unlike Large Hadron Collider (LHC) measurements, quarkonium production at the Relativistic Heavy Ion Collider (RHIC) has different production mechanisms, can access different kinematic phase space and may experience different medium densities/temperatures. The PHENIX experiment has collected a large $J / ψ \to μ^{+} μ^{-}$ data set within its unique pseudorapidity region of $1.2 < ∣ η ∣ < 2.2$ in $p + p$ , $p + A$ and $A + A$ collisions at $s$ = 200 GeV from 2014 to 2016. Latest results of normalized charged particle multiplicity dependent normalized forward $J / ψ$ yields and normalized forward $ψ (2 S)$ to $J / ψ$ ratio in 200 GeV $p + p$ collisions as well as forward $J / ψ$ azimuthal anisotropy in 200 GeV Au+Au collisions will be shown. Comparison with other RHIC and LHC measurements and latest theoretical calculations will be discussed. These PHENIX results provide their unique contributions in improving the understanding of the multi-parton interaction contribution to charmonium production and the recombination/coalescence contribution to charmonium formation within Quark Gluon Plasma (QGP) at RHIC energies.
↳ nucl-exhep-exnucl-thPoS(2025)·0 citations
19
Precision Thermodynamics of the Fermi polaron at strong coupling
S. Ramachandran · S. Jensen · Y. Alhassid
The Fermi polaron problem, which describes a mobile impurity that interacts with a spin-polarized Fermi sea, is a paradigmatic system in quantum many-body physics and has been challenging to address quantitatively in its strong coupling regime. We present the first controlled thermodynamic calculations for the Fermi polaron at strong coupling using finite-temperature auxiliary-field quantum Monte Carlo (AFMC) methods in the framework of the canonical ensemble. Modeled as a spin-imbalanced system, the Fermi polaron has a Monte Carlo sign problem, but we show that it is moderate over a wide range of temperatures and coupling strengths beyond the unitary limit of the BCS-BEC crossover. We calculate the contact, a quantity which measures the strength of the short-range correlations, as a function of temperature at unitarity and as a function of the coupling strength at fixed temperature and find good agreement with a variational approach based on one particle-hole excitation of the Fermi sea. We compare our results for the contact with recent experiments and find good agreement at unitarity (within error bars) but discrepancies away from unitarity on the BEC side of the crossover. We also calculate the thermal energy gap at unitarity as a function of temperature.
↳ cond-mat.quant-gasnucl-thPRA(2025)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE