Nuclear Theory·nucl-th

Tuesday·May 12, 2020

25 papers—12 primary·13 cross-listed

01
[Submitted on 8 May 2020]
Thermal transport in a weakly magnetized hot QCD medium
Manu Kurian🇮🇳
The thermal transport coefficients in a weakly magnetized quark-gluon plasma have been investigated within the ambit of a quasiparticle model to encode the effects of the realistic equation of state. The presence of a weak magnetic field leads to the Hall-type conductivity associated with thermal transport in the medium. An effective covariant kinetic theory has been employed to quantify the thermal dissipation while incorporating the mean field contributions in the medium. The interplay of thermal transport and electric charge transport in the weakly magnetized medium has been explored in terms of the Wiedemann-Franz law. Strong violation of the Wiedemann-Franz law has been observed in temperature regimes near to the transition temperature. The behaviour of thermal conductivity in the strong magnetic field limit has also been studied. It is observed that both the magnetic field and equation of state have a significant impact on the thermal dissipation in the medium.
Comments:
10 pages, 5 figures, Version accepted for publication in Physical Review D
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04247 [pdf]
PRD(2020)·19 citations
02
[Submitted on 9 May 2020]
Giant dipole resonance and shape evolution in Nd isotopes within TDHF method
A. Ait Ben Mennana · Y. EL Bassem · M. Oulne
The isovector giant dipole resonance (IVGDR) in even-even Nd isotopes from A=124 to A=160 is studied in the framework of time-dependent Hartree-Fock (TDHF) with Skyrme forces SkI3, SVbas, SLy5 and SLy6. The dipole strength is calculated and compared with the experimental data on photon absorption cross section $σ_{γ}$ . An overall agreement between them is obtained. The dipole strengths in $^{124 - 140} Nd$ and $^{152 - 160} Nd$ are predicted. In addition, the correlation between the quadrupole deformation parameter $β_{2}$ and the splitting $Δ E / E ˉ_{m}$ of the giant dipole resonance (GDR) spectra is studied. The results confirm that $Δ E / E ˉ_{m}$ is proportional to $β_{2}$ . Shape phase transition in Nd isotopes is also investigated in the light of IVGDR.
Comments:
24 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04337 [pdf]
Phys.Scripta(2020)·9 citations
03
[Submitted on 9 May 2020]
Timescales of quantum equilibration, dissipation and fluctuation in nuclear collisions
C. Simenel · K. Godbey · A.S. Umar
Understanding the dynamics of equilibration processes in quantum systems as well as their interplay with dissipation and fluctuation is a major challenge in quantum many-body theory. The timescales of such processes are investigated in collisions of atomic nuclei using fully microscopic approaches. Results from time-dependent Hartree-Fock (TDHF) and time-dependent random-phase approximation (TDRPA) calculations are compared for 13 systems over a broad range of energies. The timescale for full mass equilibration ( $\sim 2 \times 1 0^{- 20}$ s) is found to be much larger than timescales for neutron-to-proton equilibration, kinetic energy and angular momentum dissipations which are on the order of $1 0^{- 21}$ s. Fluctuations of mass numbers in the fragments and correlations between their neutron and proton numbers build up within only a few $1 0^{- 21}$ s. This indicates that dissipation is basically not impacted by mass equilibration, but is mostly driven by the exchange of nucleons between the fragments.
Comments:
Letter: 6 pages, 5 figures. Supplemental material (tables): 18 pages. Accepted for publication in Phys. Rev. Lett
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
arXiv:
2005.04357 [pdf]
PRL(2020)·66 citations
04
[Submitted on 9 May 2020]
Evolution of clustering structure through the momentum distributions in $^{8 - 10}$ Be isotopes
Songjie Li · Takayuki Myo · Qing Zhao · Hiroshi Toki · Hisashi Horiuchi · Chang Xu · Jian Liu · Mengjiao Lyu · Zhongzhou Ren
We investigate the evolution of clustering structure through the momentum distributions in the $^{8 - 10}$ Be isotopes. The nucleon dynamics within the inter-cluster antisymmetrization are discussed via the momentum distribution of a Brink type $α$ - $α$ wave function. For the state with a small $α$ - $α$ distance, we observe a significant depression with a dip structure at zero-momentum and an enhanced tail at relatively higher momentum region. In addition, we find the "cluster structure" in the intrinsic frame of momentum space, which is complementary to its significant $α$ -cluster dissolution in the coordinate space because of the strong antisymmetrization. For the physical $^{8 - 10}$ Be isotopes, the Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave functions are adopted. The evolution from the dilute clustering state to the compact one is demonstrated by a successive depression at the zero-momentum of nucleon distribution for the two $α$ -clusters within $^{8 - 10}$ Be isotopes. For the compact $^{10}$ Be nucleus, the momentum distribution of all nucleons shows significant depression at zero-momentum with a dip structure, which is found to be contributed by both the inter-cluster antisymmetrization and the $p$ -orbit occupation of the valence neutrons. This study proposes a new window for the investigations of the $α$ -clustering effects via the low-momentum components of nuclei, which is expected to be extended to the heavier nuclear clustering states.
Comments:
7 pages, 6 figures, under review in PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04409 [pdf]
PRC(2020)·6 citations
05
[Submitted on 10 May 2020]
Manifestation of the divergence between antisymmetrized-molecular-dynamics and container pictures of $^{9}$ Be via $^{9}$ Be( $p, p n$ ) $^{8}$ Be knockout reaction
Nguyen Tri Toan Phuc · Mengjiao Lyu · Yohei Chiba · Kazuyuki Ogata
We propose a new approach to probe the spatial extension of the valence neutron orbital in the $^{9}$ Be nucleus via the $^{9}$ Be( $p, p n$ ) $^{8}$ Be knockout reaction. This property of the nuclear molecular orbital has not been established in previous experimental studies and divergence exists between the theoretical descriptions of $^{9}$ Be from different perspectives, \textit{i.e.}, the antisymmetrized molecular dynamics and the container pictures of cluster dynamics. These pictures are represented by two different well-proven microscopic models, the antisymmetrized molecular dynamics (AMD) and Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave functions. The corresponding reduced width amplitudes (RWAs) in the $^{8}$ Be $+ n$ channel are extracted from both the AMD and THSR wave functions, and they are found to describe drastically different valence-nucleon motion, which shows the theoretical ambiguity in describing the $π$ -orbitals in $^{9}$ Be. Using the RWAs as input, the physical observables of the $^{9}$ Be( $p, p n$ ) $^{8}$ Be knockout reaction are predicted by the distorted-wave impulse approximation (DWIA) framework. The magnitudes of the triple-differential cross sections (TDX) are found to be highly sensitive to the RWA input. It is concluded that the $^{9}$ Be( $p, p n$ ) $^{8}$ Be knockout reaction could provide a feasible probing for the subtle differences between several structure models manifesting through the spatial extension of the $π$ -orbital in the $^{9}$ Be nucleus.
Comments:
5 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04582 [pdf]
PLB(2021)·2 citations
06
[Submitted on 10 May 2020]
Productions of high energy neutrons by interactions between deuteron beam and thick target
Wu Sun · Weiwei Qiu · Jun Su
The cross sections of high energy neutron-induced spallation is useful for studying the transmutation of long-life fission products. However, due to the difficulty of obtaining high-energy neutrons, the experimental data are still scarce. The present work studies the possibility to produce high energy neutrons by interactions between deuteron beam and thick target. The Geant4 toolkit is applied to simulate the interaction between the deuteron beam and thick target. An analytical method is also developed to calculate the neutron yields emitted in the interaction between the deuteron beam and thick target. The input cross section data is not only taken from the TEDNL-2017 library but also calculated by the isospin-dependent quantum molecular dynamics model. It is indicated that it is possible to produce high energy neutron by deuteron beam interaction with matter. If one wants to get high energy neutrons, low-Z matter, thin target, and small emission angle may be considered.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04601 [pdf]
0 citations
07
[Submitted on 10 May 2020]
The study of Nuclear binding energy for $A \geq 100$ based on Odd-Even staggering of nuclear masses
B. B. Jiao
The existing nuclear masses formula and nuclear masses model has undoubtedly achieved very good results, but it is still not satisfactory for some nuclear masses. Although there are many studies in Odd-Even staggering (OES) of nuclear masses, but the research on nuclear masses by using the systematicness of OES is indeed very few. Our purpose in this paper is to describe an empirical formula for Odd-Even staggering of nuclear masses that can be useful in describing and predicting nuclear masses. We empirically obtained the formula of odd-Z (odd-N) nuclei and even-Z (even-N) nuclei based on studying the OES of nuclear masses (AME2012). With the proton (neutron) empirical pairing gap from the OES of the binding energies and AME2012 database, the root-mean-square deviation of even-Z nuclei and odd-Z nuclei that we have successfully obtained 208 keV and 238 keV, respectively. The RMSD of even-N nuclei and odd-N nuclei is 222 keV and 240 keV. The result shows that our predicted values are compared well with values in AME2016, and some predicted values agree better with the experimental values. These results demonstrate that our empirical formulas have good accuracy and reliability. Another advantage of these formulas is that they use less known nuclear masses to predict unknown nuclear masses. In addition, this paper also uses BP neural network to study proton Odd-Even staggering of nuclear masses (even-Z and odd-Z nuclei) and neutron Odd-Even staggering of nuclear masses (even-N and odd-N nuclei). The RMSD of even-Z and odd-Z nuclei is 141 keV and 159 keV; the RMSD of even-N and odd-N nuclei is 150 keV and 160 keV. The results show that the RMSD of nuclear masses based on neural network 60-80 keV decrease than that based on empirical formula (the accuracy is increased by about 32%). Accurate nuclear mass is helpful to the research of nuclear physics, nuclear technology and astrophysics.
Comments:
13 pages,6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04636 [pdf]
0 citations
08
[Submitted on 10 May 2020]
Non-resonant Density of States Enhancement at Low Energies for Three or Four Neutrons
Michael D. Higgins · Chris H. Greene · Alejandro Kievsky · Michele Viviani
The low energy systems of three or four neutrons are treated within the adiabatic hyperspherical framework, yielding an understanding of the low energy quantum states in terms of an adiabatic potential energy curve. The dominant low energy potential curve for each system, computed here using widely accepted nucleon-nucleon interactions with and without the inclusion of a three-nucleon force, shows no sign of a low energy resonance. However, both systems exhibit a low energy enhancement of the density of states, or of the Wigner-Smith time-delay, which derives from long-range universal physics analogous to the Efimov effect. That enhancement could be relevant to understanding the low energy excess of correlated 4-neutron ejection events observed experimentally in a nuclear reaction by Kisamori et al.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2005.04714 [pdf]
PRL(2020)·42 citations
09
[Submitted on 10 May 2020]
A Fourier-Cumulant Analysis for Multiharmonic Flow Fluctuation
Seyed Farid Taghavi🇩🇪
The Fourier analysis of the final particle distribution followed by cumulant study of the Fourier coefficient event-by-event fluctuation is one of the main approaches for testing the collective evolution in the heavy-ion collision. Using a multidimensional generating function, we propose a method to extract any possible cumulant of multiharmonic flow fluctuations and classify them in terms of the order of cumulants and harmonics involved in them. In particular, we show that there are 33 distinct cumulants with orders $2, 3, 4, 5$ and harmonics $2, 3, 4, 5$ . We compute the normalized version of these cumulants from hydrodynamic simulation for Pb--Pb collisions based on {\tt T $_{R}$ ENTo}+{\tt VISH2+1}+{\tt UrQMD}. We compare the simulation with those normalized cumulants that the LHC has measured and predict the unmeasured ones. Comparing the initial and final state fluctuation normalized cumulants, we compute the linear and nonlinear hydrodynamic response couplings. We finally introduce the genuine three-particle correlation function containing information of all third-order cumulants.
Comments:
32 pages, 6 figures, 3 ancillary files
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2005.04742 [pdf]
EPJC(2021)·15 citations
10
[Submitted on 10 May 2020]
Thermal Fluctuations in Nuclear Pasta
M. E. Caplan🇺🇸 · C. R. Forsman🇺🇸 · A. S. Schneider🇸🇪
Despite their astrophysical relevance, nuclear pasta phases are relatively unstudied at high temperatures. We present molecular dynamics simulations of symmetric nuclear matter with several topologies of `lasagna' at a range of temperatures to study the pasta-uniform transition. Using the Minkowski functionals we quantify trends in the occupied volume, surface area, mean breadth, and Euler characteristic. The amplitude of surface displacements of the pasta increase with temperature which produce short lived topological defects such as holes and filaments near melting, resulting in power laws for increasing surface curvature with temperature. We calculate the static structure factor and report the shear viscosity and thermal conductivity of pasta, finding that the shear viscosity is minimized at the melting temperature. These results may have implications for the thermoelastic properties of nuclear pasta and finite temperature corrections to the equation of state at pasta densities.
Comments:
13 pages, 8 figures, PRC accepted
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); cond-mat.soft (cond-mat.soft)
arXiv:
2005.04766 [pdf]
PRC(2021)·17 citations
11
[Submitted on 11 May 2020]
Laser-nucleus interactions in the sudden regime
Sergei Kobzak · Hans A. Weidenmüller · Adriana Pálffy
The interaction between medium-weight nuclei and a strong zeptosecond laser pulse of MeV photons is investigated theoretically. Multiple absorption of photons competes with nuclear equilibration. We investigate the sudden regime. Here the rate of photon absorption is so strong that there is no time for the nucleus to fully equilibrate after each photon absorption process. We follow the temporal evolution of the system in terms of a set of rate equations. These account for dipole absorption and induced dipole emission, equilibration (modeled in terms of particle-hole states coupled by the residual nuclear interaction), and neutron decay (populating a chain of proton-rich nuclei). Our results are compared with earlier work addressing the adiabatic regime where equilibration is instantaneous. We predict the degree of excitation and the range of nuclei reached by neutron evaporation. These findings are relevant for planning future experiments.
Comments:
v3, final
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2005.04981 [pdf]
PRC(2021)·3 citations
12
[Submitted on 11 May 2020]
Exploring the $Λ$ -deuteron interaction via correlations in heavy-ion collisions
J. Haidenbauer🇩🇪
$Λ$ -deuteron two-particle momentum correlation functions, to be measured in high-energy heavy-ion collisions, are investigated. In particular, the question is addressed whether such correlations can serve as an additional and alternative source of information on the elementary $Λ N$ interaction. The study is performed within the Lednicky-Lyuboshits formalism, utilizing an effective range expansion for the two relevant $S$ -wave $Λ d$ amplitudes with parameters taken from the literature. It is found that in collisions characterized by a large emitting source the $Λ d$ correlation function is predominatly sensitive to the quartet state ( $^{4} S_{3/2}$ ). In contrast, for small source sizes the contribution from the doublet partial wave ( $^{2} S_{1/2}$ ) could be significant. Though the latter is constrained by the hypertriton binding energy, its present experimental uncertainty impedes an accurate determination of the doublet amplitude and, in turn, complicates conclusions on the quartet state.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2005.05012 [pdf]
PRC(2020)·32 citations
13
[Submitted on 8 May 2020] (cross-list from astro-ph.HE)
Dark matter or correlated errors: Systematics of the AMS-02 antiproton excess
Jan Heisig🇧🇪 · Michael Korsmeier🇮🇹 · Martin Wolfgang Winkler🇸🇪
Several studies have pointed out an excess in the AMS-02 antiproton spectrum at rigidities of 10-20 GV. Its spectral properties were found to be consistent with a dark-matter particle of mass 50-100 GeV which annihilates hadronically at roughly the thermal rate. In this work, we reinvestigate the antiproton excess including all relevant sources of systematic errors. Most importantly, we perform a realistic estimate of the correlations in the AMS-02 systematic error which could potentially "fake" a dark-matter signal. The dominant systematics in the relevant rigidity range originate from uncertainties in the cross sections for absorption of cosmic rays within the detector material. For the first time, we calculate their correlations within the full Glauber-Gribov theory of inelastic scattering. The AMS-02 correlations enter our spectral search for dark matter in the form of covariance matrices which we make publicly available for the cosmic-ray community. We find that the global significance of the antiproton excess is reduced to below 1 $σ$ once all systematics, including the derived AMS-02 error correlations, are taken into account. No significant preference for a dark-matter signal in the AMS-02 antiproton data is found in the mass range 10-10000 GeV.
Comments:
17 pages + references, 6 figures; ancillary files contain covariance matrices of the AMS-02 errors (antiproton flux, antiproton/proton, proton flux, helium flux, B/C) and correlation matrices for the absorption cross section error (antiproton-carbon, proton-carbon); v2: presentation improved, references added, results unchanged
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2005.04237 [pdf]
PRResearch(2020)·102 citations
14
[Submitted on 9 May 2020] (cross-list from hep-ph)
Non-perturbative Enhancement of Heavy Quark-Antiquark Pair Annihilation in the Quark-Gluon Plasma
Xin Wu🇨🇳 · Min He🇨🇳
The annihilation of heavy particles close to thermal equilibrium, which plays a prominent role in the chemical equilibration of heavy quarks in the Quark-Gluon Plasma (QGP) as well as in many classic dark matter scenarios, is reexamined. We derive a scattering amplitude that resums near-threshold attractive interaction of the annihilating particles in terms of the non-relativistic scattering $T$ -matrix and Green's function, thereby capturing the pertinent Sommerfeld enhancement from both nonperturbative scattering state and bound state solutions. The derived formula is of such generality that it applies to arbitrary partial wave processes of two-particle annihilation, and enables to incorporate finite widths of the annihilating particles. In a screened potential model, the non-perturbative scattering amplitude is computed and the Sommerfeld enhancement is identified for heavy quark-antiquark annihilation in the QGP.
Comments:
7 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04416 [pdf]
PRD(2020)·0 citations
15
[Submitted on 9 May 2020] (cross-list from nucl-ex)
A Search for the Quark-Hadron Phase Transition in pp collisions at $s$ = 13 TeV using UrQMD model
Swarnapratim Bhattacharyya🇮🇳
Charged particle multiplicity fluctuations in pp collisions at $s$ = 13 TeV have been studied by the method of scaled factorial moment for the minimum bias events generated by Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model in the pseudo-rapidity ({\eta}), azimuthal angle ( $ϕ$ ) and two dimensional anisotropic ( $η$ - $ϕ$ ) phase space. Strong intermittent type of fluctuations have been observed for the UrQMD simulated data. Systematic studies of intermittent fluctuations in terms of scaled factorial moments was utilized to extract the anomalous fractal dimension in the pseudo-rapidity ({\eta}), azimuthal angle ( $ϕ$ ) and two dimensional anisotropic ( $η$ - $ϕ$ ) phase space. Search for the quark-hadron phase transition in the framework of Ginzburg-Landau theory of second-order phase transition by the analysis with the factorial moment method has also been performed.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04488 [pdf]
0 citations
16
[Submitted on 10 May 2020] (cross-list from hep-ph)
Dense Baryonic Matter and Applications of QCD Phase Diagram Dualities
T. G. Khunjua🇬🇪 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺
Recently it has been found that quantum chromodynamics (QCD) phase diagram possesses a duality between chiral symmetry breaking and pion condensation. For the first time this was revealed in the QCD motivated toy model. Then it was demonstrated in effective models as well and new additional dualities being found. We briefly recap the main features of this story and then discuss its applications as a tool to explore the QCD phase structure. The most appealing application is the possibility of getting the results on the QCD phase diagram at large baryon density. Taking the idea from large $1/ N_{c}$ universalities it was argued that the scenario of circumventing the sign problem with the help of dualities seems plausible. It is also discussed that there is a persistent problem about whether there should be catalysis or anti-catalysis of chiral symmetry breaking by chiral imbalance. One can probably say that the issue is settled after lattice results (first principle approach), where the catalysis was observed. But they used an unphysically large pion mass so it is still interesting to get additional indications that this is the case. It is shown just by the duality property that there exists catalysis of chiral symmetry breaking. So, having in mind our results and the earlier lattice simulations, one can probably claim that this issue is settled. It is demonstrated that the duality can be used to obtain new results. As an example, it is showcased how the phase structure of dense quark matter with chiral imbalance (with possibility of inhomogeneous phases) can be obtained from the knowledge of a QCD phase diagram with isopin asymmetry.
Comments:
Published in the Special Issue "Selected Papers from Theory of Hadronic Matter under Extreme Conditions"
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2005.04641 [pdf]
Particles(2020)·14 citations
17
[Submitted on 10 May 2020] (cross-list from hep-ph)
Dense baryonic matter with chiral imbalance and charged pion condensation
T. G. Khunjua🇺🇸 · K. G. Klimenko🇷🇺 · R. N. Zhokhov🇷🇺
After the first predictions in seventies that in dense nuclear matter, for example, in neutron stars there could be pion condensation phenomenon, it was shown that at least s-wave pion condensation is unlikely to occur in such a medium in different approaches including NJL model consideration with neutrality and $β$ -equilibrium condition. Then it has been found a condition that can promote this phenomenon in dense baryonic matter, it is chiral imbalance, so now it is interesting if this generation can survive rather strict requirement of electric neutrality and $β$ -equilibrium. Here in this paper the generation of pion condensation in dense baryonic matter by chiral imbalance is investigated. It is shown that electric neutrality and $β$ -equilibrium conditions do not spoil this phenomenon and this leads to interesting applications for physics of neutron stars. There are several possible mechanisms of generation of chiral imbalance in dense matter. In a view of latest and forthcoming NICER results and the first observed and possibly new events of neutron star mergers it is rather interesting to explore how possible chiral imbalance in neutron star can influence and change EOS and, hence, mass-radius relation. It is a first step in that direction.
Comments:
Presented at Excited QCD 2020, 2-8 February 2020, Krynica Zdroj, Poland
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2005.04649 [pdf]
Acta Phys.Polon.Supp.(2021)·8 citations
18
[Submitted on 10 May 2020] (cross-list from nucl-ex)
Spectroscopy of low spin states in 157Dy: Search for evidence of enhanced octupole correlations
S. N. T. Majola🇿🇦 · R. A. Bark🇿🇦 · L. Bianco🇨🇦 · T. D. Bucher🇿🇦 · S. P. Bvumbi🇿🇦 · D. M. Cullen🇫🇮 · P. E. Garrett🇨🇦 · P. T. Greenlees🇫🇮 · D. Hartley🇺🇸 · J Hirvonen🇫🇮 · U. Jakobsson🇫🇮 · P. M. Jones🇿🇦 and 31 other authors
Low-spin states of 157Dy have been studied using the JUROGAM II array, following the 155Gd ({\alpha}, 2n) reaction at a beam energy of 25 MeV. The level scheme of 157Dy has been expanded with four new bands. Rotational structures built on the [523]5/2- and [402]3/2+ neutron orbitals constitute new additions to the level scheme as do many of the inter- and intra-band transitions. This manuscript also reports the observation of cross I- to (I-1)- and I- to (I-1)+ E1 dipole transitions inter-linking structures built on the [523]5/2- (band 5) and [402]3/2+ (band 7) neutron orbitals. These interlacing band structures are interpreted as the bands of parity doublets with simplex quantum number s = -i related to possible octupole correlations.
Comments:
Published in Physical Review C (2019)
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04655 [pdf]
PRC(2019)·6 citations
19
[Submitted on 10 May 2020] (cross-list from hep-lat)
Smooth flux-sheets with topological winding modes
A. Bakry🇨🇳 · M. Deliyergiyev🇵🇱 · A. Galal🇪🇬 · M. Khalil Williams🇩🇪
The inclusion of the Gaussian-curvature term in the bulk of Polyakov-Kleinert string action renders new boundary terms and conditions by Gauss-Bonnet theorem. Within a leading approximation, the eigenmodes of smooth worldsheets and the free-energy of a gas of open rigid strings appears to be altered at second order in the coupling by the topological term . In analogy to the topological $θ$ term, the Gauss-Bonnet term is introduced into the effective action with a complex coupling to implement signed energy shifts. We investigate the rigid color flux-sheets between two static color sources near the critical point in the light of the topologically induced shifts. The Yang-Mills lattice data of the potential of static quark-antiquark $Q Q ˉ$ in a heatbath is compared to the string potential. The Monte-Carlo data correspond to link-integrated Polyakov-loop correlators averaged over SU(3) gauge configurations at $β = 6.0$ . Substantial improvement in the fit behavior is displayed over the nonperturbative source separation distance $0.2$ fm to $1.0$ fm. Remarkably, the returned coupling parameter of the topological term from the fit exhibits a proportionality to a quantum number. These findings suggest that the manifested modes are the winding number of a topological particle on the string's worldsheet.
Comments:
6 pages, 3 figures, 2 Tables
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2005.04675 [pdf]
4 citations
20
[Submitted on 10 May 2020] (cross-list from nucl-ex)
First candidates for {\gamma} vibrational bands built on the [505]11/2- neutron orbital in odd-A Dy isotopes
S.N.T. Majola🇿🇦 · M.A. Sithole🇿🇦 · L. Mdletshe🇿🇦 · D. Hartley🇺🇸 · J. Timar🇭🇺 · B.M. Nyako🇭🇺 · J.M. Allmond🇺🇸 · R.A. Bark🇿🇦 · C. Beausang🇺🇸 · L. Bianco🇨🇦 · T.D. Bucher🇿🇦 · S.P. Bvumbi and 58 other authors
Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the 155Gd({\alpha},2n)157Dy and 148Nd(12C, 5n)155Dy reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a K{\pi}= 2+ {\gamma} vibrational band, built on the [505]11/2- neutron orbital, in both odd-A 155, 157Dy isotopes. The coupling of the first excited K=0+ states or the so-called \b{eta} vibrational bands at 661 and 676 keV in 154Dy and 156Dy to the [505]11/2- orbital, to produce a K{\pi}=11/2- band, was not observed in both 155Dy and 157Dy, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the core nuclei 154Dy and 156Dy are also discussed.
Comments:
Published in Physical Rev C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04699 [pdf]
PRC(2020)·5 citations
21
[Submitted on 10 May 2020] (cross-list from nucl-ex)
Observation of $γ$ -vibrations and alignments built on non-ground-state configurations in 156Dy
S. N. T. Majola🇿🇦 · D. J. Hartley🇺🇸 · L.L. Riedinger🇺🇸 · J.F. Sharpey-Schafer🇿🇦 · J. M. Allmond🇺🇸 · C. Beausang🇺🇸 · M.P. Carpenter🇺🇸 · C.J. Chiara🇺🇸 · N. Cooper🇺🇸 · D. Curien🇫🇷 · B. J. P. Gall🇫🇷 · P.E. Garrett🇨🇦 and 16 other authors
The exact nature of the lowest $K^{π} = 2_{γ}^{+}$ rotational bands in all deformed nuclei remains obscure. Traditionally they are assumed to be collective vibrations of the nuclear shape in the $γ$ degree of freedom perpendicular to the nuclear symmetry axis. Very few such $γ$ -bands have been traced past the usual back-bending rotational alignments of high-j nucleons. We have investigated the structure of positive-parity bands in the N=90 nucleus 156Dy, using the 148Nd(12C,4n)156Dy reaction at 65 MeV, observing the resulting $γ$ -ray transitions with the Gammasphere array. The even- and odd-spin members of the $K^{π} = 2_{γ}^{+}$ $γ$ -band are observed to 32+ and 31+ respectively. This rotational band faithfully tracks the ground-state configuration to the highest spins. The members of a possible $γ$ -vibration built on the aligned yrast S-band are observed to spins 28+ and 27+. An even-spin positive-parity band, observed to spin 24+, is a candidate for an aligned S-band built on the seniority-zero configuration of the $0_{2}^{+}$ state at 676 keV. The crossing of this band with the $0_{2}^{+}$ band is at $ℏ ω$ = 0.28(1) MeV and is consistent with the configuration of the $0_{2}^{+}$ band not producing any blocking of the monopole pairing.
Comments:
Published in Physics Review C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04706 [pdf]
PRC(2015)·25 citations
22
[Submitted on 10 May 2020] (cross-list from cond-mat.supr-con)
Unconventional superconductivity as a synchronization problem in nuclear oscillator networks
V. Velasco · M. B. Silva Neto
We formulate the problem of unconventional $d -$ wave superconductivity, with phase fluctuations, pseudogap phenomenon, and local Cooper pairs, in terms of a synchronization problem in random, quantum dissipative, elasto-nuclear oscillator networks. The nodes of the network correspond to {\it localized, collective quadrupolar vibrations} of nuclei-like, elastic inhomogeneities embedded in a dissipative medium. Electrons interacting with such vibrations form local Cooper pairs, with a superfluid $d -$ wave pseudogap $Δ_{P G}$ , due to an effective, short range attractive interaction of $d_{x^{2} - y^{2}}$ character. Phase coherent, bulk superconductivity, with a $d -$ wave gap $Δ$ , is stabilized when the oscillator network is asymptotically entangled in a nearly decoherence-free environment. Phase coherence will in turn be destroyed, at $T_{c}$ , when the thermal noise becomes comparable to the coupling between oscillators, the superfluid density $K$ . The $2Δ/ k_{B} T_{c}$ ratio is a function of Kuramoto's order parameter, $r = 1 - K_{c} / K$ , for the loss of synchronization at $K_{c}$ , and is much larger than the nonuniversal $2 Δ_{P G} / k_{B} T^{*}$ ratio, where $T^{*}$ is the temperature at which $Δ_{P G}$ is completely destroyed by thermal fluctuations. We discuss our findings in connection to the available data for various unconventionally high-temperature superconductors.
Comments:
8 pages, 6 figures
Subjects:
Superconductivity (cond-mat.supr-con); nlin.AO (nlin.AO); Nuclear Theory (nucl-th)
arXiv:
2005.04713 [pdf]
J.Phys.Comm.(2021)·1 citation
23
[Submitted on 10 May 2020] (cross-list from hep-lat)
$F_{K} / F_{π}$ from Möbius domain-wall fermions solved on gradient-flowed HISQ ensembles
Nolan Miller🇺🇸 · Henry Monge-Camacho🇺🇸 · Chia Cheng Chang🇯🇵 · Ben Hörz🇺🇸 · Enrico Rinaldi🇯🇵 · Dean Howarth🇺🇸 · Evan Berkowitz🇺🇸 · David A. Brantley🇺🇸 · Arjun Singh Gambhir🇺🇸 · Christopher Körber🇺🇸 · Christopher J. Monahan🇺🇸 · M. A. Clark🇺🇸 and 6 other authors
We report the results of a lattice quantum chromodynamics calculation of $F_{K} / F_{π}$ using Möbius domain-wall fermions computed on gradient-flowed $N_{f} = 2 + 1 + 1$ highly-improved staggered quark (HISQ) ensembles. The calculation is performed with five values of the pion mass ranging from $130 ≲ m_{π} ≲ 400$ MeV, four lattice spacings of $a \sim 0.15, 0.12, 0.09$ and $0.06$ fm and multiple values of the lattice volume. The interpolation/extrapolation to the physical pion and kaon mass point, the continuum, and infinite volume limits are performed with a variety of different extrapolation functions utilizing both the relevant mixed-action effective field theory expressions as well as discretization-enhanced continuum chiral perturbation theory formulas. We find that the $a \sim 0.06$ fm ensemble is helpful, but not necessary to achieve a subpercent determination of $F_{K} / F_{π}$ . We also include an estimate of the strong isospin breaking corrections and arrive at a final result of $F_{K^{\pm}} / F_{π^{\pm}} = 1.1942 (45)$ with all sources of statistical and systematic uncertainty included. This is consistent with the Flavour Lattice Averaging Group average value, providing an important benchmark for our lattice action. Combining our result with experimental measurements of the pion and kaon leptonic decays leads to a determination of $∣ V_{u s} ∣/∣ V_{u d} ∣ = 0.2311 (10)$ .
Comments:
v3: published version; v2: version submitted to journal; v1: 26 pages including 13 figures, appendices, and references. See https://github.com/callat-qcd/project_fkfpi for the analysis and data
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2005.04795 [pdf]
PRD(2020)·57 citations
24
[Submitted on 11 May 2020] (cross-list from hep-ph)
Excitation function of initial temperature of heavy flavor quarkonium emission source in high energy collisions
Qi Wang🇨🇳 · Fu-Hu Liu🇨🇳
The transverse momentum spectra of $J / ψ$ , $ψ (2 S)$ , and $Υ (n S, n = 1, 2, 3)$ produced in proton-proton ( $p$ + $p$ ), proton-antiproton ( $p$ + $p ˉ$ ), proton-lead ( $p$ +Pb), gold-gold (Au+Au), and lead-lead (Pb+Pb) collisions over a wide energy range are analyzed by the (two-component) Erlang distribution, the Hagedorn function (the inverse power-law), and the Tsallis-Levy function. The initial temperature is obtained from the color string percolation model due to the fit by the (two-component) Erlang distribution in the framework of multisource thermal model. The excitation functions of some parameters such as the mean transverse momentum and initial temperature increase from dozens of GeV to above 10 TeV. The mean transverse momentum and initial temperature decrease (increase slightly or do not change obviously) with the increase of rapidity (centrality). Meanwhile, the mean transverse momentum of $Υ (n S, n = 1, 2, 3)$ is larger than that of $J / ψ$ and $ψ (2 S)$ , and the initial temperature for $Υ (n S, n = 1, 2, 3)$ emission is higher than that for $J / ψ$ and $ψ (2 S)$ emission, which shows a mass-dependent behavior.
Comments:
26 pages, 12 figures. Advances in High Energy Physics, accepted
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.04940 [pdf]
Adv.High Energy Phys.(2020)·10 citations
25
[Submitted on 11 May 2020] (cross-list from hep-ph)
$ϕ$ meson mass and decay width in strange hadronic matter
Rajesh Kumar🇮🇳 · Arvind Kumar🇮🇳
The in-medium mass and decay width of the $ϕ$ meson in the hot asymmetric strange hadronic matter are calculated using an effective Lagrangian approach for $ϕ$ $K K ˉ$ interaction. The in-medium contributions of $K K ˉ$ loop to the $ϕ$ meson self-energy are computed by the medium modified kaon and antikaon mass which is evaluated using the chiral SU(3) model. To deal with the ultraviolet divergence, we regularize the loop integral of self-energy with a dipole form factor, and present the results for cut-off mass, $Λ_{c}$ =3 GeV. In chiral model calculations, for strange matter, we find that the mass of kaons and antikaons decreases with the increase in baryonic density whereas the finite temperature causes an increase in the mass. We observed that the in-medium $ϕ$ meson mass decreases slowly with baryonic density whereas the decay width increases rapidly. The results in the present investigation support result in the literature which indicate a small downward shift in mass and a large broadening in the decay width. In the asymmetric strange hadronic matter, the study of the $ϕ$ mesons can be relevant for the compressed strange baryonic matter and experimental observables such as dilepton spectra which can result from the experiments in the future FAIR facility at GSI.
Comments:
27 pages and 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2005.05133 [pdf]
PRC(2020)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE