Nuclear Theory·nucl-th

Wednesday·January 31, 2024

11 papers—6 primary·5 cross-listed

01
Properties of chiral nucleon-nucleon interaction at N $^{3}$ LO with high cutoffs studied by local projection
Haoyu Shang🇨🇳 · Rongzhe Hu🇨🇳 · Junchen Pei🇨🇳 · Furong Xu🇨🇳
The chiral nucleon-nucleon ( $N N$ ) interaction at high cutoffs has been plagued by the presence of spurious bound states. In this work, the chiral $N N$ interaction at N $^{3}$ LO is studied by the local projection method as the cutoff increases. The evolution of short-range behaviors of pion-exchange interactions and contact interactions is intuitively demonstrated. The $P$ -channel potentials toward high cutoffs appear to be erratic at short ranges to compromise with phase shifts, while such erratic behaviors can be avoided in $S$ and $D$ channels. Furthermore, a chiral $N N$ interaction at N $^{3}$ LO is studied at a cutoff of 700 MeV. The properties of deuteron and triton are testified with this interaction. Such a hard interaction is expected to provide an alternative choice for studies of short-range correlations and high density nuclear matter.
nucl-thPRC(2024)·1 citation
02
Bottomonium suppression in 5.02 and 8.16 TeV p-Pb collisions
Michael Strickland🇺🇸 · Sabin Thapa🇺🇸 · Ramona Vogt🇺🇸
We compute the suppression of Upsilon(1S), Upsilon(2S), and Upsilon(3S) states in p-Pb collisions relative to pp collisions, including nuclear parton distribution function (nPDF) effects, coherent energy loss, momentum broadening, and final-state interactions in the quark-gluon plasma. We employ the EPPS21 nPDFs and calculate the uncertainty resulting from variation over the associated error sets. To compute coherent energy loss and momentum broadening, we follow the approach of Arleo, Peigne, and collaborators. The 3+1D viscous hydrodynamical background evolution of the quark-gluon plasma is generated by anisotropic hydrodynamics. The in-medium suppression of bottomonium in the quark-gluon plasma is computed using a next-to-leading-order open quantum system framework formulated within potential nonrelativistic quantum chromodynamics. We find that inclusion of all these effects provides a reasonable description of experimental data from the ALICE, ATLAS, CMS, and LHCb collaborations for the suppression of Upsilon(1S), Upsilon(2S), and Upsilon(3S) as a function of both transverse momentum and rapidity.
nucl-thhep-phPRD(2024)·11 citations
03
Impact of Hot Inner Crust on Compact Stars at Finite Temperature
Clara Dehman · Mario Centelles · Xavier Viñas
We conducted a study on the thermal properties of stellar matter with the nuclear energy density functional BCPM. This functional is based on microscopic Brueckner-Hartree-Fock calculations and has demonstrated success in describing cold neutron stars. To enhance its applicability in astrophysics, in this study we extend the BCPM equation of state to finite temperature for $β$ -stable neutrino-free matter, taking into consideration the hot inner crust. Such an equation of state holds significant importance for hot compact objects, particularly those resulting from a binary neutron star merger event. Our exploration has shown that with increasing temperature there is a fast decrease of the crust-core transition density, suggesting that for hot stars it is not realistic to assume a fixed value of this density. The microscopic calculations also reveal that the presence of nuclear clusters persists up to $T = 7.21$ MeV, identified as the limiting temperature of the crust. Above this threshold, the manifestation of clusters is not anticipated. Below this temperature, clusters within the inner crust are surrounded by uniform matter with varying densities, allowing for the distinction between the upper and lower transition density branches. Moreover, we computed mass--radius relations of neutron stars, assuming an isothermal profile for $β$ -stable neutron star matter at various temperature values. Our findings highlight the significant influence of the hot inner crust on the mass--radius relationship, leading to the formation of larger and more inflated neutron stars. Consequently, under our prescription, the final outcome is a unified equation of state at finite temperature.
nucl-thastro-ph.HEastro-ph.SRAstron.Astrophys.(2024)·7 citations
04
Compton Scattering on 4He with Nuclear One- and Two-Body Densities
Harald 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.)🇺🇸
We present the first \emph{ab initio} calculation of elastic Compton scattering from 4He. It is carried out to $O (e^{2} δ^{3})$ [N3LO] in the $δ$ expansion of $χ$ EFT. At this order and for this target, the only free parameters are the scalar-isoscalar electric and magnetic dipole polarisabilities of the nucleon. Adopting current values for these yields a parameter-free prediction. This compares favourably with the world data from HI $γ$ S, Illinois and Lund for photon energies $50 MeV ≲ ω ≲ 120 MeV$ within our theoretical uncertainties of $\pm 10%$ . We predict a cross section up to 7 times that for deuterium. As in 3He, this emphasises and tests the key role of meson-exchange 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 two-body densities generated from 5 chiral potentials and the AV18 $+$ UIX potential are available using the python package provided at \url{https://pypi.org/project/nucdens/}.
nucl-thnucl-exEPJA(2024)·6 citations
05
Nuclear scattering via quantum computing
Peiyan Wang🇨🇳 · Weijie Du🇺🇸 · Wei Zuo🇨🇳 · James P. Vary🇺🇸
We propose a hybrid quantum-classical framework to solve the elastic scattering phase shift of two well-bound nuclei in an uncoupled channel. Within this framework, we develop a many-body formalism in which the continuum scattering states of the two colliding nuclei are regulated by a weak external harmonic oscillator potential with varying strength. Based on our formalism, we propose an approach to compute the eigenenergies of the low-lying scattering states of the relative motion of the colliding nuclei as a function of the oscillator strength of the confining potential. Utilizing the modified effective range expansion, we extrapolate the elastic scattering phase shift of the colliding nuclei from these eigenenergies to the limit when the external potential vanishes. In our hybrid approach, we leverage the advantage of quantum computing to solve for these eigenenergies from a set of many-nucleon Hamiltonian eigenvalue problems. These eigenenergies are inputs to classical computers to obtain the phase shift. We demonstrate our framework with two simple problems, where we implement the rodeo algorithm to solve the relevant eigenenergies with the IBM Qiskit quantum simulator. The results of both the spectra and the elastic scattering phase shifts agree well with other theoretical results.
nucl-thquant-phPRC(2024)·24 citations
06
Photon-triggered jets as probes of multi-stage jet modification
C. Sirimanna🇺🇸 · Y. Tachibana🇯🇵 · A. Angerami · R. Arora · S. A. Bass · S. Cao · Y. Chen · L. Du · R. Ehlers · H. Elfner · W. Fan · R. J. Fries and 41 other authors
Prompt photons are created in the early stages of heavy ion collisions and traverse the QGP medium without any interaction. Therefore, photon-triggered jets can be used to study the jet quenching in the QGP medium. In this work, photon-triggered jets are studied through different jet and jet substructure observables for different collision systems and energies using the JETSCAPE framework. Since the multistage evolution used in the JETSCAPE framework is adequate to describe a wide range of experimental observables simultaneously using the same parameter tune, we use the same parameters tuned for jet and leading hadron studies. The same isolation criteria used in the experimental analysis are used to identify prompt photons for better comparison. For the first time, high-accuracy JETSCAPE results are compared with multi-energy LHC and RHIC measurements to better understand the deviations observed in prior studies. This study highlights the importance of multistage evolution for the simultaneous description of experimental observables through different collision systems and energies using a single parameter tune.
nucl-thhep-phEPJ Web Conf.(2024)·2 citations
07
Isovector Axial Charge and Form Factors of Nucleons from Lattice QCD
Rajan Gupta🇺🇸
I present an overview of the calculations of the isovector axial vector form factor of the nucleon, $G_{A} (Q^{2})$ , using lattice QCD. Based on a comparison of results from various collaborations, a case is made that lattice results are now consistent within 10\%. A similar level of uncertainty is found also in the axial charge $g_{A}^{u - d}$ , the mean squared axial charge radius, $⟨ r_{A}^{2} ⟩$ , the induced pseudoscalar charge $g_{P}^{*}$ , and the pion-nucleon coupling $g_{π N N}$ . These lattice results for $G_{A} (Q^{2})$ are already compatible with those obtained from the recent MINER $ν$ A experiment but lie 2-3 $σ$ higher than the phenomenological extraction from the old $ν$ -deuterium bubble chamber scattering data for $Q^{2} > 0.3$ ~GeV $^{2}$ . Fits to our data show that the dipole ansatz does not have enough parameters to parameterize the form factor over the range $0 \leq Q^{2} \leq 1$ ~GeV $^{2}$ , whereas even a $z^{2}$ truncation of the $z$ -expansion or a low order Padé are sufficient. Looking ahead, lattice QCD calculations will provide increasingly precise results over the range $0 \leq Q^{2} ≲ 1$ ~GeV $^{2}$ , and MINER $ν$ A-like experiments will extend the range to $Q^{2} \sim 2$ ~GeV $^{2}$ or higher. To increase precision of lattice data to the percent level, new developments are needed to address two related issues: the exponentially falling signal-to-noise ratio in all nucleon correlation functions and removing excited state contributions. Nevertheless, even with the current methodology, significant reduction in errors is expected over the next few years with higher statistics data on more ensembles closer to the physical point.
↳ hep-lathep-phnucl-thUniverse(2024)·13 citations
08
Mass, spectroscopy and two-neutron decay of $^{16}$ Be
B. Monteagudo🇫🇷 · F.M. Marqués🇫🇷 · J. Gibelin🇫🇷 · N.A. Orr🇫🇷 · A. Corsi🇫🇷 · Y. Kubota🇯🇵 · J. Casal🇮🇹 · J. Gómez-Camacho🇪🇸 · G. Authelet🇫🇷 · H. Baba🇯🇵 · C. Caesar🇩🇪 · D. Calvet🇫🇷 and 56 other authors
The structure and decay of the most neutron-rich beryllium isotope, $^{16}$ Be, has been investigated following proton knockout from a high-energy $^{17}$ B beam. Two relatively narrow resonances were observed for the first time, with energies of $0.84 (3)$ and $2.15 (5)$ MeV above the two-neutron decay threshold and widths of $0.32 (8)$ and $0.95 (15)$ MeV respectively. These were assigned to be the ground ( $J^{π} = 0^{+}$ ) and first excited ( $2^{+}$ ) state, with $E_{x} = 1.31 (6)$ MeV. The mass excess of $^{16}$ Be was thus deduced to be $56.93 (13)$ MeV, some $0.5$ MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wavefunction during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2 $^{+}$ level presents a far more diffuse neutron-neutron distribution.
↳ nucl-exnucl-thPRL(2024)·20 citations
09
Coherent $γ^{*}$ -nucleus scattering and coherent nuclear states
Alfred H. Mueller🇺🇸
In the context of a McLerran-Venugopalan (MV) model for a large nucleus, coherent scattering of a virtual photon on that nucleus is evaluated in the $A_{-} = 0$ gauge, the gauge appropriate for the target nucleus. The evaluation of the scattering in $A_{-} = 0$ gauge is very intricate compared to the usual $A_{+} = 0$ gauge evaluation natural for the scattering process, but has the advantage of directly giving the scattering in terms of a partonic description of the nucleus. In the limit where a tagged forward jet puts the dipole-nucleus scattering in the saturation regime the coherent reactions are equal to the inelastic reactions. In terms of the nuclear wave function the coherent reactions come from color singlet and zero total transverse momentum quark-antiquark pairs in the wave function and in the saturation regime the nuclear wave function is a coherent state for these pairs. In the saturation region half of all quarks (or antiquarks) come from zero momentum and color charge pairs.
↳ hep-phnucl-thJHEP(2024)·3 citations
10
Heavy flavour hadron production in relativistic heavy ion collisions at RHIC and LHC in EPOS4HQ
Jiaxing Zhao🇫🇷 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Vitalii Ozvenchuk🇵🇱 · Klaus Werner🇫🇷
Employing the recently developed EPOS4HQ event generator, we study the production of different heavy-flavor mesons in relativistic heavy-ion collisions at RHIC and LHC energies. The transverse momentum spectra, yield ratio, nuclear modification factor, and elliptic flow can be well described in the EPOS4HQ framework. We furthermore analyze the processes which modify these observables as compared to $pp$ collisions and are at the origin of the experimentally determined nuclear modification factor $R_{AA}$ .
↳ hep-phnucl-thPRC(2024)·32 citations
11
Diffractive deep inelastic scattering at NLO in the dipole picture
Guillaume Beuf🇵🇱 · Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · Risto Paatelainen🇫🇮 · Jani Penttala🇺🇸
We compute the transverse and longitudinal diffractive structure functions to full next-to-leading order accuracy in the dipole picture of deep inelastic scattering. Our calculation uses the standard light-cone perturbation theory method for the partonic content of the virtual photon, together with the Color Glass Condensate description of the target color field. Our result includes as a subset the $q q ˉ g$ contribution calculated earlier. We show that there is a rapidity divergence that can be factorized into the BK/JIMWLK evolution of the target Wilson lines, and that all other divergences cancel.
↳ hep-phnucl-thJHEP(2024)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE