Nuclear Theory·nucl-th

Wednesday·December 8, 2021

11 papers—6 primary·5 cross-listed

01
[Submitted on 6 Dec 2021]
Fate of Multiparticle Resonances: From $Q$ -Balls to $^{3}$ He Droplets
Dam Thanh Son🇺🇸 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸
We consider a system of $N$ nonrelativistic particles which form a near-threshold resonance. Assuming no subset of these particles can form a bound state, the resonance can only decay through an "explosion" into $N$ particles. We show that the decay width of the resonance scales as $E^{Δ - 5/2}$ in the limit when the energy $E$ of the resonance goes to zero, where $Δ$ is the ground state energy of a system of $N$ particles in a spherical harmonic trap with unit frequency. The formula remains valid when some pairs of final particles have zero-energy $s$ -wave resonance, but the Efimov effect is not present. In the limit of large $N$ , we show that the final particles follow a Maxwell-Boltzmann distribution if they are bosons, and a semicircle-like law if they are fermions. We argue that metastable $^{3}$ He droplets exist with the lifetime varying over many orders of magnitudes ranging from a fraction of a nanosecond to values greatly exceeding the age of the Universe.
Comments:
6 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph); Mathematical Physics (math-ph); math.MP (math.MP)
arXiv:
2112.03318 [pdf]
PRA(2022)·10 citations
02
[Submitted on 6 Dec 2021]
Higher-order transverse momentum fluctuations in heavy-ion collisions
Somadutta Bhatta🇺🇸 · Chunjian Zhang🇺🇸 · Jiangyong Jia🇺🇸
In relativistic heavy-ion collisions, the event-by-event mean transverse momentum fluctuations are sensitive to overlap area and energy density fluctuations in initial state. We present a framework to calculate $p_{T}$ fluctuations up to $4^{th}$ -order using standard and subevent methods, which is validated using the HIJING model. We observe a power-law dependence for cumulants of all orders as a function of charged particle multiplicity $N_{ch}$ , consistent with a simple independent source picture. The fluctuation in $pp$ collisions is observed to be larger than for $p +$ Pb, Pb+Pb and Xe+Xe collisions at the same $N_{ch}$ due to bias in number of contributing sources. The short-range correlations are greatly suppressed in subevent method in comparison to calculations based on the standard method. This study provides a baseline for transverse momentum fluctuations without the presence of final state effects.
Comments:
5 pages, 4 figures, replace with published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2112.03397 [pdf]
PRC(2022)·24 citations
03
[Submitted on 7 Dec 2021]
Density dependence of the nuclear symmetry energy and neutron skin thickness in the KIDS framework
Panagiota Papakonstantinou
The KIDS framework for the nuclear equation of state (EoS) and energy density functional (EDF) offers the possibility to explore systematically the effect of EoS parameters on predictions for a variety of observables. The EoS parameters can be varied independently of each other and independently of assumptions regarding the in-medium nucleon effective mass. Here I present a pilot study of the neutron skin thickness (NST) in nuclei of current interest. The results indicate that variations of the symmetry energy slope parameter L by roughly 10 MeV and variations of the droplet-model counterpart of the curvature parameter $K_{τ}$ by roughly 20 MeV affect predictions by comparable amounts. However, structural details may also have sizable effects on predictions, notably in the cases of $^{68}$ Ni and $^{208}$ Pb. This work is part of a systematic investigation of the NST within the KIDS framework and of a broader effort to constrain the density dependence of the nuclear symmetry energy.
Comments:
6 pages incl. figure, 2 tables; prepared for HNPS Adv. Nucl. Phys. (Proc. 29th Symposium of the HNPS, September 2021); a complementary KIDS study with explicit neutron-star constraints can be found in arXiv:2112.00996
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2112.03514 [pdf]
Adv.Nucl.Phys.(2022)·2 citations
04
[Submitted on 7 Dec 2021]
Systematic study for the surface properties of neutron star
Ankit Kumar · H. C. Das · Jeet Amrit Pattnaik · S. K. Patra
[Background] In our earlier work {\bf [Phys. Rev. C 104, 055804 (2021)]}, we studied the surface properties of a neutron star, assuming it as a huge finite nucleus containing protons, neutrons, electrons, and muons. For the first time, we reported these results of a neutron star for a few representative masses. In the present paper, we give a detailed study of these quantities to draw definite conclusions. [Method]To carry forward our earlier idea, the energy density functional of the momentum space of neutron star matter is converted to the coordinate space in a local density approximation. This functional is again used to derive the neutron star surface properties within the coherent density fluctuation model using the weight function obtained from the density profile of the neutron star using the recently developed G3 and widely used NL3 and IU-FSU parameter sets in the context of relativistic mean-field formalism. [Results] The systematic surface properties of the neutron star, such as incompressibility, symmetry energy, slope parameter, and curvature coefficient, is calculated. The volume and surface components of the total symmetry energy are decomposed with the help of the $κ$ factor obtained from the volume to surface ratio of the symmetry energies in the liquid drop limit of Danielewicz. The magnitude of the computed surface quantities increases with the neutron star's mass. [Conclusion] The incompressibility $K^{star}$ , symmetry energy $S^{star}$ , slope parameter $L_{sym}^{star}$ and curvature coefficient $K_{sym}^{star}$ of the neutron stars with different mass are analyzed and found to be model dependent. NL3 is the stiffest equation of state endue us with the higher magnitude of surface quantities as compared to the G3 and IU-FSU forces.
Comments:
9 pages, 8 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2112.03519 [pdf]
PRC(2022)·1 citation
05
[Submitted on 7 Dec 2021]
Collision centrality and system size dependences of light nuclei production via dynamical coalescence mechanism
Yi-Lin Cheng · Song Zhang · Yu-Gang Ma
Light (anti-)nuclei in relativistic heavy-ion collisions are considered to be formed by the coalescence mechanism of (anti-)nucleons in the present work. Using a dynamical phase-space coalescence model coupled with a multi-phase transport (AMPT) model, we explore the formation of light clusters such as deuteron, triton and their anti-particles in different centralities for $^{197}$ Au + $^{197}$ Au collisions at $s_{N N} = 39$ GeV. The calculated transverse momentum spectra of protons, deuterons, and tritons are comparable to those of experimental data from the RHIC-STAR collaboration. Both coalescence parameters $B_{2}$ for (anti-)deuteron and $B_{3}$ for triton increase with the transverse momentum as well as the collision centrality, and they are comparable with the measured values in experiments. The effect of system size on the production of light nuclei is also investigated by $^{10}$ B + $^{10}$ B, $^{16}$ O + $^{16}$ O, $^{40}$ Ca + $^{40}$ Ca, and $^{197}$ Au + $^{197}$ Au systems in central collisions. The results show that yields of light nuclei increase with system size, while the values of coalescence parameters present an opposite trend. It is interesting to see that the system size, as well as the centrality dependence of $B_{A}$ ( $A$ = 2, 3), falls into the same group, which further demonstrates production probability of light nuclei is proportional to the size of the fireball. Furthermore, we compare our coalescence results with other models, such as the thermal model and analytic coalescence model, it seems that the description of light nuclei production is consistent with each other.
Comments:
11 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2112.03520 [pdf]
EPJA(2021)·11 citations
06
[Submitted on 7 Dec 2021]
Local variations of charge radii for nuclei with even $Z$ from 84 to 120
Rong An · Xiao-Xu Dong · Li-Gang Cao · Feng-Shou Zhang
Pronounced changes of nuclear charge radii provide a stringent benchmark on the theoretical models and play a vital role in recognizing various nuclear phenomena. In this work, the systematic evolutions of nuclear charge radii along even $Z$ =84-120 isotopic chains are firstly investigated by the recently developed new ansatz under the covariant density functional. The calculated results show that the shell closure effects of nuclear charge radii are remarkably shown at the neutron numbers $N = 126$ and 184. Interestingly, the arch-like shapes of charge radii between these two strong neutron closed shells are naturally observed. Across the $N = 184$ shell closure, the abrupt increase in charge radii is still evidently emerged. In addition, the rapid raise of nuclear charge radii from the neutron numbers $N = 138$ to $N = 144$ is also disclosed clearly in superheavy regions due to the enhanced shape deformation.
Comments:
23 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.03829 [pdf]
Commun.Theor.Phys.(2023)·13 citations
07
[Submitted on 6 Dec 2021] (cross-list from hep-ph)
Pole position of the $a_{1} (1260)$ resonance in a three-body unitary framework
Daniel Sadasivan🇺🇸 · Andrei Alexandru🇺🇸 · Hakan Akdag🇩🇪 · Felipe Amorim🇺🇸 · Ruairí Brett🇺🇸 · Chris Culver🇬🇧 · Michael Döring🇺🇸 · Frank X. Lee🇺🇸 · Maxim Mai🇺🇸
Masses, widths, and branching ratios of hadronic resonances are quantified by their pole positions and residues with respect to transition amplitudes on the Riemann sheets of the complex energy-plane. In this study we discuss the analytic structure in the physical energy region of three-body scattering amplitudes on such manifolds. As an application, we determine the pole position of the $a_{1} (1260)$ meson from the ALEPH experiment by allowing for $π ρ$ coupled channels in S- and D-wave. We find it to be $s_{0} = (123 2_{- 0 - 11}^{+ 15 + 9} - i 26 6_{- 22 - 27}^{+ 0 + 15}) MeV$ .
Comments:
17 pages, 13 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2112.03355 [pdf]
PRD(2022)·50 citations
08
[Submitted on 6 Dec 2021] (cross-list from nucl-ex)
Nuclear Charge Radii of the Nickel Isotopes $^{58 - 68, 70}$ Ni
S. Malbrunot-Ettenauer🇨🇭 · S. Kaufmann🇩🇪 · S. Bacca🇩🇪 · C. Barbieri🇬🇧 · J. Billowes🇬🇧 · M. L. Bissell🇬🇧 · K. Blaum🇩🇪 · B. Cheal🇬🇧 · T. Duguet🇫🇷 · R. F. Garcia Ruiz🇨🇭 · W. Gins🇧🇪 · C. Gorges🇩🇪 and 29 other authors
Collinear laser spectroscopy is performed on the nickel isotopes $^{58 - 68, 70}$ Ni, using a time-resolved photon counting system. From the measured isotope shifts, nuclear charge radii $R_{c}$ are extracted and compared to theoretical results. Three ab initio approaches all employ, among others, the chiral interaction NNLO $_{sat}$ , which allows an assessment of their accuracy. We find agreement with experiment in differential radii $δ ⟨ r_{c}^{2} ⟩$ for all employed ab initio methods and interactions, while the absolute radii are consistent with data only for NNLO $_{sat}$ . Within nuclear density functional theory, the Skyrme functional SV-min matches experiment more closely than the Fayans functional Fy( $Δ r$ ,HFB).
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2112.03382 [pdf]
PRL(2022)·78 citations
09
[Submitted on 6 Dec 2021] (cross-list from hep-ph)
Sum rule for the partial decay rates of bottom hadrons based on the dynamical supersymmetry of the $s ˉ$ quark and the $u d$ diquark
Taiju Amano🇯🇵 · Daisuke Jido🇯🇵 · Stefan Leupold🇸🇪
We investigate the weak decays of $B ˉ_{s}^{0}$ and $Λ_{b}$ to charm hadrons based on the dynamical supersymmetry between the $s ˉ$ quark and the $u d$ diquark. We derive a new sum rule relating the decay rates of the processes $B ˉ_{s}^{0} \to D_{s}^{+} P^{-}$ , $B ˉ_{s}^{0} \to D_{s}^{*+} P^{-}$ and $Λ_{b} \to Λ_{c} P^{-}$ , where $P^{-}$ is a negatively charged meson, such as $π^{-}$ and $K^{-}$ . It is found that the observed decay rates satisfy the sum rule very well. This implies that the supersymmetry between the $s ˉ$ quark and the $u d$ diquark is also seen in the wavefunctions of the heavy hadrons and suggests that the $u d$ diquark can be regarded as a valid effective constituent for heavy hadrons.
Comments:
5 pages, 1 figure, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.03409 [pdf]
PRD(2022)·6 citations
10
[Submitted on 7 Dec 2021] (cross-list from hep-ph)
On transverse momentum broadening in real-time lattice simulations of the glasma and in the weak-field limit
Andreas Ipp🇦🇹 · David I. Müller🇦🇹 · Daniel Schuh🇦🇹
In these proceedings, we report on our numerical lattice simulations of partons traversing the boost-invariant, non-perturbative glasma as created at the early stages of collisions at RHIC and LHC. Since these highly energetic partons are produced from hard scatterings during heavy-ion collisions, they are already affected by the first stage of the medium's time evolution, the glasma, which is the pre-equilibrium precursor state of the quark-gluon plasma. We find that partons quickly accumulate transverse momentum up to the saturation momentum during the glasma stage. Moreover, we observe an interesting anisotropy in transverse momentum broadening of partons with larger broadening in the rapidity than in the azimuthal direction. Its origin can be related to correlations among the longitudinal color-electric and color-magnetic flux tubes in the initial state of the glasma. We compare these observations to the semi-analytic results obtained by a weak-field approximation, where we also find such an anisotropy in a parton's transverse momentum broadening.
Comments:
8 pages, 3 figures, submitted to vConf2021 conference proceedings
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.03883 [pdf]
EPJ Web Conf.(2022)·1 citation
11
[Submitted on 7 Dec 2021] (cross-list from hep-ph)
Event topology and global observables in heavy-ion collisions at the Large Hadron Collider
Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Debadatta Behera🇮🇳 · Raghunath Sahoo🇮🇳 · Sushanta Tripathy🇮🇹
Particle production and event topology are very strongly correlated in high-energy hadronic and nuclear collisions. Event topology is decided by the underlying particle production dynamics and medium effects. Transverse spherocity is an event shape observable, which has been used in pp and heavy-ion collisions to separate the events based on their geometrical shapes. It has the unique capability to distinguish between jetty and isotropic events. In this work, we have implemented transverse spherocity in Pb-Pb collisions at $s_{NN}$ = 5.02 TeV using A Multi-Phase Transport Model (AMPT). While awaiting for experimental explorations, we perform a feasibility study of dependence of transverse spherocity on some of the global observables in heavy-ion collisions at the Large Hadron Collider energies. These global observables include the Bjorken energy density ( $ϵ_{B_{j}}$ ), speed of sound ( $c_{s}^{2}$ ) in the medium and the kinetic freeze-out properties for different collision centralities. The present study reveals about the usefulness of event topology dependent measurements in heavy-ion collisions in contrast to proton-proton collisions.
Comments:
Same as the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2112.03892 [pdf]
Sci.Rep.(2022)·34 citations

Affiliations

first authorsco-authorsvia INSPIRE