Nuclear Theory·nucl-th

Thursday·June 3, 2021

11 papers—3 primary·8 cross-listed

01
[Submitted on 2 Jun 2021]
Shell effect in $A =$ 116--124 Tin isotopes investigated using isotopic analysis of proton scattering at 295 MeV
Yoshiko Kanada-En'yo
Proton elastic scattering off Sn isotopes at $E_{p} = 295$ MeV in the mass number range of $A =$ 116--124 was investigated using calculation employing relativistic impulse approximation (RIA) with theoretical densities obtained for the Sn isotopes from relativistic Hartree-Bogoliubov (RHB) and nonrelativistic Skyrme Hartree-Fock-Bogoliubov (SHFB) calculations of spherical nuclei. In the RIA calculations, a modified version of the Murdock and Horowitz model that includes a density dependence in the effective nucleon-nucleon ( $N N$ ) interaction was used. A calculation using the theoretical density obtained from a relativistic calculation employing the DD-ME2 interaction successfully reproduced the experimental data for $^{122}$ Sn $(p, p)$ , but it overestimated the $^{116}$ Sn $(p, p)$ and $^{118}$ Sn $(p, p)$ cross sections at backward angles. Isotopic analyses of the $(p, p)$ reactions combined with nuclear structure properties were performed based on reaction calculations that used a model density modified from the DD-ME2 density to optimize the neutron density of the Sn isotopes by fitting the isotopic cross section ratios. The resulting optimized density reproduced the experimental $(p, p)$ data for the series of Sn isotopes from $^{116}$ Sn to $^{124}$ Sn. The neutron root-mean-square(rms) radii and the skin thickness of the Sn isotopes obtained in the present analysis exhibited smooth $A$ dependences in the range of $A =$ 116--124, which are consistent with the theoretical predictions obtained using the DD-ME2 interaction but seem to contradict the experimental results determined from the $(p, p)$ data. In a detailed analysis of the surface neutron density probed by proton elastic scattering, a signal of the shell effect at $N = 66$ in Sn isotopes was found.
Comments:
17 pages, 15 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2106.00930 [pdf]
1 citation
02
[Submitted on 2 Jun 2021]
Phase-space distributions of nuclear short-range correlations
W. Cosyn🇺🇸 · J. Ryckebusch🇧🇪
Nuclear short-range correlations (SRCs) induce high-momentum/high-energy fluctuations in the nuclear medium. In order to assess their impact on nuclear bulk properties, like nuclear radii and kinetic energies, it is instrumental to determine how SRCs are distributed in phase space as this sheds light on the connection between their appearance in coordinate and momentum space. Using the lowest-order correlation operator approximation (LCA) to include SRC, we compute two-dimensional nuclear Wigner quasiprobability distributions $w (r, k)$ to locate those $(r, k)$ phase-space regions that are most heavily impacted by SRCs. The SRC-induced high-momentum components find their origin in a radial range that is confined to the nuclear interior. Significant SRCs strength is generated in the full momentum range $0 \leq k ≲ 5 fm^{- 1}$ covered in this work, but below the Fermi momentum those are dwarfed by the mean-field contributions. As an application of $w (r, k)$ , we focus on the radial dependence of the kinetic energy $T$ and the momentum dependence of the radius $r_{rms}$ for the symmetric nuclei $^{12}$ C, $^{40}$ Ca and the asymmetric nucleus $^{48}$ Ca. The kinetic energy almost doubles after including SRCs, with the largest increase occurring in the nuclear interior $r ≲ 2$ fm. The momentum dependence of the $r_{rms}$ teaches that the largest contributions stem from $k ≲ 2$ fm $^{- 1}$ , where the SRCs induce a slight reduction of the order of a few percent. The SRCs systematically reduce the $^{48}$ Ca neutron skin by an amount that can be 10\%.
Comments:
10 pages, 6 figures; revised version with updated Fig.1, matches published version
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2106.01249 [pdf]
PLB(2021)·22 citations
03
[Submitted on 2 Jun 2021]
Singular Value Decomposition and Similarity Renormalization Group Evolution of Nuclear Interactions
B. Zhu · R. Wirth · H. Hergert
One of the main challenges for ab initio nuclear many-body theory is the growth of computational and storage costs as calculations are extended to heavy, exotic, and structurally complex nuclei. Here, we investigate the factorization of nuclear interactions as a means to address this issue. We perform Singular Value Decompositions of nucleon-nucleon interactions in partial wave representation and study the dependence of the singular value spectrum on interaction characteristics like regularization scheme and resolution scales. We develop and implement the Similarity Renormalization Group (SRG) evolution of the factorized interaction, and demonstrate that this SVD-SRG approach accurately preserves two-nucleon observables. We find that low-resolution interactions allow the truncation of the SVD at low rank, and that a small number of relevant components is sufficient to capture the nuclear interaction and perform an accurate SRG evolution, while the Coulomb interaction requires special consideration. The rank is uniform across all partial waves, and almost independent of the basis choice in the tested cases. This suggests an interpretation of the relevant singular components as mere representations of a small set of abstract operators that can describe the interaction and its SRG flow. Following the traditional workflow for nuclear interactions, we discuss how the transformation between the center-of-mass and laboratory frames creates redundant copies of the partial wave components when implemented in matrix representation, and we discuss strategies for mitigation. Finally, we test the low-rank approximation to the SRG-evolved interactions in many-body calculations using the In-Medium SRG. By including nuclear radii in our analysis, we verify that the implementation of the SRG using the singular vectors of the interaction does not spoil the evolution of other observables.
Comments:
16 pages, 16 figures. Comments are welcome!
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2106.01302 [pdf]
PRC(2021)·16 citations
04
[Submitted on 1 Jun 2021] (cross-list from hep-ph)
Electroproduction of heavy vector mesons using holographic QCD: from near threshold to high energy regimes
Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
We develop a non-perturbative analysis of the electro-production of heavy vector mesons ( $ϕ$ , $J /Ψ$ ) from threshold to high energy. We use the holographic construction with bulk confinement enforced through a soft wall. Using Witten diagrams, we evaluate the pertinent cross sections for heavy vector mesons ( $ϕ$ , $J /Ψ$ ) production and study their dependence on both the incoming virtual photon polarization as well as the outgoing polarization of the heavy meson. Our results for $J /Ψ$ electro-production compares well with the available HERA data at low and intermediate $Q^{2}$ , and for a wide range of momentum transfer. We also predict the quasi-real electro-production of $J /Ψ$ near threshold.
Comments:
30 pages (with two columns), 13 figures, extension of our work on photo-production arXiv:1910.04707 with overlapping appendix
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2106.00722 [pdf]
PRD(2021)·25 citations
05
[Submitted on 1 Jun 2021] (cross-list from hep-ph)
Electromagnetic radii of the nucleon in soft-wall holographic QCD
Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸
We revisit the electromagnetic form factors of the proton and neutron in the original-minimal soft-wall holographic QCD, which has only two parameters, i.e., the mass scale $κ$ and the twist parameter of the nucleon $τ$ . We first fix $τ = 3$ by the hard scattering rule, and extract $κ = 0.402 GeV$ from the world data (including the Mainz A1 data) of the Sachs magnetic form factor of the proton $G_{M}^{p}$ . We then predict among others, the charge radius of the proton to be $r_{p} = 0.831 \pm 0.008 fm$ , in perfect agreement with the recent charge radius of the proton measured by the PRad collaboration at Jefferson Lab, and in agreement with the muonic hydrogen experiments. Our prediction for the proton elastic form factor ratio $μ_{p} G_{E}^{p} / G_{M}^{p}$ is also in very good agreement with the recent high precision Jefferson Lab recoil polarization experiment E08-007 for $Q^{2} = 0.3 - 0.6 GeV^{2}$ , and with the recent high precision Mainz A1 experiment for $Q^{2} < 0.13 GeV^{2}$ .
Comments:
v2: significantly improved, 14 pages (with two columns), 4 figures, 2 tables, our conclusion has changed (we know have perfect agreement with the PRad measurement of the charge radius of the proton, i.e., in the original-minimal soft-wall holographic QCD, we have predicted the charge radius of the proton to be $r_{p} = 0.831 \pm 0.008 fm$ .)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2106.00752 [pdf]
NPB(2023)·18 citations
06
[Submitted on 1 Jun 2021] (cross-list from hep-th)
Gibbs entropy from entanglement in electric quenches
Adrien Florio🇺🇸 · Dmitri E. Kharzeev🇺🇸
In quantum electrodynamics with charged fermions, a background electric field is the source of the chiral anomaly which creates a chirally imbalanced state of fermions. This chiral state is realized through the production of entangled pairs of right-moving fermions and left-moving antifermions (or vice versa, depending on the orientation of the electric field). Here we show that the statistical Gibbs entropy associated with these pairs is equal to the entropy of entanglement between the right-moving particles and left-moving antiparticles. We then derive an asymptotic expansion for the entanglement entropy in terms of the cumulants of the multiplicity distribution of produced particles and explain how to re-sum this asymptotic expansion. Finally, we study the time dependence of the entanglement entropy in a specific time-dependent pulsed background electric field, the so-called "Sauter pulse", and illustrate how our resummation method works in this specific case. We also find that short pulses (such as the ones created by high energy collisions) result in an approximately thermal distribution for the produced particles.
Comments:
13 pages, 4 figures. Minor modifications and some typos corrected. Matches published version
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2106.00838 [pdf]
PRD(2021)·22 citations
07
[Submitted on 2 Jun 2021] (cross-list from hep-ph)
Effect of the pion field on the distributions of pressure and shear in the proton
Shiryo Owa🇦🇺 · A. W. Thomas🇦🇺 · X.G. Wang🇦🇺
In light of recent experimental progress in determining the pressure and shear distributions in the proton, these quantities are calculated in a model with confined quarks supplemented by the pion field required by chiral symmetry. The incorporation of the pion contributions is shown to account for the long-range distributions, in general agreement with the experimentally extracted quark contributions. The results of the model are also compared with lattice QCD results at unphysically large quark mass.
Comments:
5 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2106.00929 [pdf]
PLB(2022)·14 citations
08
[Submitted on 2 Jun 2021] (cross-list from hep-ph)
Bottomonia production in p+p collisions under NRQCD formalism
Vineet Kumar🇮🇳 · Kinkar Saha🇮🇳 · Prashant Shukla🇮🇳 · Abhijit Bhattacharyya🇮🇳
In this work, we present the calculation of the production cross sections of bottomonia states using Non-Relativistic Quantum Chromodynamics (NRQCD) formalism. The direct production cross-section of a resonance can be factorised in terms of short distance Quantum Chromodynamics (QCD) cross sections and long distance matrix elements (LDMEs) under NRQCD. We use a large set of measured $Υ$ (nS) production data at Tevatron and LHC energies in both central and forward rapidity regions to extract the LDMEs with better precision. The feed down contributions from the higher states including the $χ_{b}$ (3P) state are taken into account for the LDME extraction. The formalism provides a good description of the bottomonia data in wide transverse momentum range at different collision energies.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2106.00940 [pdf]
NPA(2021)·1 citation
09
[Submitted on 2 Jun 2021] (cross-list from hep-ph)
The Self-energy of Nucleon for the Photon-proton Elastic Scattering and the Electromagnetic Polarizability
Susumu Kinpara
The effect of the self-energy on the photon-proton elastic scattering is investigated for the backward and the forward directions. The shape of the Thomson scattering at the photon energy $ω \to 0$ is broken by taking into account the self-energy of proton. The electromagnetic polarizabilities $α ˉ \pm β ˉ$ are calculated by the lowest-order perturbative treatment.
Comments:
10 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2106.00971 [pdf]
1 citation
10
[Submitted on 2 Jun 2021] (cross-list from hep-ph)
In-medium kinetic theory of $D$ mesons and heavy-flavor transport coefficients
Juan M. Torres-Rincon🇩🇪 · Glòria Montaña🇪🇸 · Àngels Ramos🇪🇸 · Laura Tolos🇪🇸
We extend the kinetic theory of $D$ mesons to accommodate thermal and off-shell effects due to the medium modification of the heavy-meson spectral functions. From the Kadanoff-Baym approach we derive the off-shell Fokker-Planck equation which encodes the heavy-flavor transport coefficients. We analyze the thermal width (damping rate) of $D$ mesons due to their scattering off light mesons, focusing on new in-medium effects: off-shell corrections, inelastic channels, and the contribution of the Landau cut. We obtain that the latter effect (absent for vacuum scattering amplitudes) brings sizable corrections at moderate temperatures. We discuss how the heavy-flavor transport coefficients, like the drag and diffusion coefficients, are modified in matter. We find that the $D$ -meson spatial diffusion coefficient matches smoothly to the latest results of lattice-QCD calculations and Bayesian analyses at higher temperatures.
Comments:
47 pages, 14 figures. Theoretical foundations largely abridged (we refer to v1 for details). Extended discussions and added new figures. Results unmodified. Version published by Physical Review C journal
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2106.01156 [pdf]
PRC(2022)·24 citations
11
[Submitted on 2 Jun 2021] (cross-list from hep-ph)
The bosonic algebraic approach applied to the $[QQ] [Q ˉ Q ˉ]$ tetraquarks
A. J. Majarshin🇨🇳 · Yan-An Luo🇨🇳 · Feng Pan🇨🇳 · Jorge Segovia🇪🇸
The exact eigenenergies of the $T_{4 c} = [cc] [c ˉ c ˉ]$ , $T_{4 b} = [bb] [b ˉ b ˉ]$ , and $T_{2 [b c]} = [b c] [b ˉ c ˉ]$ tetraquarks are calculated within the extended transitional Hamiltonian approach, in which the so-called Bethe \emph{ansatz} within an infinite-dimensional Lie algebra is used. We fit the parameters appearing in the transitional region from phenomenology associated with potential candidates of tetraquarks. The rotation and vibration transitional theory seems to provide a better description of heavy tetraquarks than other attempts within the same formalism. Our results indicate that the pairing strengths are large enough to provide binding; an extended comparison with the current literature is also performed.
Comments:
8 pages, 2 figures, 3 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2106.01179 [pdf]
PRD(2022)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE