Nuclear Theory·nucl-th

Tuesday·March 30, 2021

15 papers—7 primary·8 cross-listed

01
[Submitted on 26 Mar 2021]
Emergent four-body parameter in universal two-species bosonic systems
Lorenzo Contessi🇫🇷 · Johannes Kirscher🇬🇧 · Manuel Pavon Valderrama🇨🇳
The description of unitary few-boson systems is conceptually simple: only one parameter -- the three-body binding energy -- is required to predict the binding energies of clusters with an arbitrary number of bosons. Whether this correlation between the three- and many-boson systems still holds for two species of bosons for which only the inter-species interaction is resonant depends on how many particles of each species are in the system. For few-body clusters with species $A$ and $B$ and a resonant $A B$ interaction, it is known that the emergent $AA B$ and $A B B$ three-body scales are correlated to the ground-state binding energies of the $AAA B$ and $A B B B$ systems, respectively. We find that this link between three and four bodies is broken for the $AA B B$ tetramer whose binding energy is neither constrained by the $AA B$ nor by the $A B B$ trimer. From this de-correlation, we predict the existence of a scale unique to the $AA B B$ tetramer. In our explanation of this phenomenon, we understand the $AA B B$ and $AAA B$ / $A B B B$ tetramers as representatives of two different universal classes of $N$ -body systems with distinct renormalization-group and discrete-scaling properties.
Comments:
15 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); physics.atm-clus (physics.atm-clus); Quantum Physics (quant-ph)
arXiv:
2103.14711 [pdf]
PLA(2021)·3 citations
02
[Submitted on 26 Mar 2021]
Effects of Strong Magnetic Fields on the Hadron-Quark Deconfinement Transition
Betânia C. T. Backes🇧🇷 · Kauan D. Marquez🇧🇷 · Débora P. Menezes🇧🇷
The aim of the present work is to investigate the effects of strong magnetic fields on the hadron-quark phase transition point at zero temperature. To describe the hadronic phase, a relativistic mean field (RMF) model is used and to describe the quark phase a density dependent quark mass model (DDQM) is employed. As compared with the results obtained with non-magnetised matter, we observe a shift of the transition point towards higher pressures and, generally also towards higher chemical potentials. An investigation of the phase transitions that could sustain hybrid stars is also performed.
Comments:
8 pages, 5 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th)
arXiv:
2103.14733 [pdf]
EPJA(2021)·17 citations
03
[Submitted on 27 Mar 2021]
Generation of fragment angular momentum in fission
J. Randrup🇺🇸 · R. Vogt🇺🇸
A recent analysis of experimental data [J. Wilson $e t . a l$ , Nature $590$ , 566 (2021)] found that the angular momenta of nuclear fission fragments are uncorrelated. Based on this finding, the authors concluded that the spins are therefore determined only $a f t er$ scission has occurred. We show here that the nucleon-exchange mechanism, as implemented in the well-established event-by-event fission model $FREYA$ , while agitating collective rotational modes in which the two spins are highly correlated, nevertheless leads to fragment spins that are largely uncorrelated. This fact invalidates the reasoning of those authors. Furthermore, it was reported [J. Wilson $e t . a l$ , Nature $590$ , 566 (2021)] that the mass dependence of the average fragment spin has a sawtooth structure. We demonstrate that such a behavior naturally emerges when shell and deformation effects are included in the moments of inertia of the fragments at scission.
Comments:
5 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2103.14778 [pdf]
PRL(2021)·69 citations
04
[Submitted on 29 Mar 2021]
Higher order cumulants of transverse momentum and harmonic flow in relativistic heavy ion collisions
Piotr Bozek🇵🇱 · Rupam Samanta🇵🇱
Higher order symmetric cumulants of global collective observables in heavy ion collisions are studied. The symmetric cumulants can be straightforwardly constructed for scalar observables: the average transverse momentum, the multiplicity, and the squares of harmonic flow vectors. Third and fourth order cumulants are calculated in the hydrodynamic model. A linear predictor of the average transverse momentum and harmonic flow coefficients in a collision is used to predict the value of the cumulants from the moments of the initial distribution. The symmetric cumulants divided by the averages (or the standard deviations) of the considered observables can be used as a fine tool to study correlations present in the initial state of the collision.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2103.15338 [pdf]
PRC(2021)·17 citations
05
[Submitted on 29 Mar 2021]
QCD at finite chemical potential in and out-of equilibrium
Olga Soloveva🇩🇪 · Pierre Moreau🇺🇸 · Elena Bratkovskaya🇩🇪
We review the transport properties of the strongly interacting quark-gluon plasma (QGP) created in heavy-ion collisions at ultrarelativistic energies, i.e. out-of equilibrium, and compare them to the equilibrium properties. The description of the strongly interacting (non-perturbative) QGP in equilibrium is based on the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation-of-state of the partonic system above the deconfinement temperature $T_{c}$ from lattice QCD. We study the transport coefficients such as the ratio of shear viscosity and bulk viscosity over entropy density, diffusion coefficients, electric conductivity etc. versus temperature and baryon chemical potential. Based on a microscopic transport description of heavy-ion collisions we, furthermore, discuss which observables are sensitive to the QGP formation and its properties.
Comments:
15 pages, 5 figures, contribution to the Proceedings of the 9th International Conference on New Frontiers in Physics (ICNFP 2020), 4 Sep.-2 Oct. 2020, Creta, Greece
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2103.15417 [pdf]
Phys.Scripta(2021)·4 citations
06
[Submitted on 29 Mar 2021]
Nuclear Fermi Momenta of $^{2}$ H, $^{27}$ Al and $^{56}$ Fe from an Analysis of CLAS data
Hui Liu🇨🇳 · Na-Na Ma🇨🇳 · Rong Wang🇨🇳
Nuclear Fermi momentum is a basic property of a nucleus where many nucleons dwell. However, in experiments only the nuclear Fermi momenta of just a few nuclei are measured using quasielastic electron scattering on the nuclear targets so far. Particularly, we still do not know experimentally the Fermi momentum of the lightest nucleon composite -- the deuteron. In this paper, we apply both gaussian distribution and Cauchy distribution to describe the quasielastic peak in the cross section of electron-nucleus scattering. The dip of the cross-section ratio at about $x_{B} = 1$ is explained with the nuclear Fermi momentum. By performing the least-square fits to the published CLAS data in the narrow kinematic region of quasielastic scattering, we obtain the nuclear Fermi momenta of $^{2}$ H, $^{27}$ Al and $^{56}$ Fe, which are $116 \pm 7$ MeV/c, $232 \pm 27$ MeV/c, and $244 \pm 28$ MeV/c respectively. The extracted nuclear Fermi momenta are compared to the simple calculations based on Fermi gas model, and the consistencies are found.
Comments:
7 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2103.15609 [pdf]
NPA(2022)·1 citation
07
[Submitted on 29 Mar 2021]
Deuteron-Deuteron Correlation Function in Nucleus-Nucleus Collisions
Stanislaw Mrowczynski🇵🇱 · Patrycja Slon🇵🇱
A formula of the $D$ - $D$ correlation function is derived. The deuterons are treated either as elementary particles or as neutron-proton bound states. In the first case the deuterons are directly emitted from a source and in the second one the deuteron formation is a final-state process simultaneous with a generation of $D$ - $D$ correlation. The source radius of deuterons formed due to final-state interactions is bigger by the factor of $2$ than that of directly emitted deuterons. To check how sizable is the effect we compute the $D$ - $D$ correlation function taking into the Bose-Einstein statistics of deuterons, the $s$ -wave scattering due to strong interaction and the Coulomb repulsion. The correlation function is shown to be sensitive to the source radius for sources which are sufficiently small with RMS radii smaller than 3.5 fm. Otherwise the correlation function is dominated by the Coulomb repulsion and weakly depends on the source radius. Measurements which can make use of our finding are discussed.
Comments:
9 pages, 4 figures, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2103.15761 [pdf]
PRC(2021)·22 citations
08
[Submitted on 26 Mar 2021] (cross-list from hep-ph)
From hydro to jet quenching, coalescence and hadron cascade: a coupled approach to solving the $R_{AA} \otimes v_{2}$ puzzle
Wenbin Zhao🇨🇳 · Weiyao Ke🇺🇸 · Wei Chen🇨🇳 · Tan Luo🇪🇸 · Xin-Nian Wang🇨🇳
Hydrodynamics and jet quenching are responsible for the elliptic flow $v_{2}$ and suppression of large transverse momentum ( $p_{T}$ ) hadrons, respectively, two of the most important phenomena leading to the discovery of a strongly coupled quark-gluon plasma (QGP) in high-energy heavy-ion collisions. A consistent description of the hadron suppression factor $R_{AA}$ and $v_{2}$ , especially at intermediate $p_{T}$ , however, remains a challenge. We solve this long-standing $R_{AA} \otimes v_{2}$ puzzle by including quark coalescence for hadronization and final state hadron cascade in the coupled linear Boltzmann transport-hydro model that combines concurrent jet transport and hydrodynamic evolution of the bulk medium. We illustrate that quark coalescence and hadron cascade, two keys to solving the puzzle, also lead to a splitting of $v_{2}$ for pions, kaons and protons in the intermediate $p_{T}$ region. We demonstrate for the first time that experimental data on $R_{AA}$ , $v_{2}$ and their hadron flavor dependence from low to intermediate and high $p_{T}$ in high-energy heavy-ion collisions can be understood within this coupled framework.
Comments:
4 pages in RevTex with 6 figures. Final published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2103.14657 [pdf]
PRL(2022)·88 citations
09
[Submitted on 26 Mar 2021] (cross-list from hep-ph)
Quenching effects in the cumulative jet spectrum
Adam Takacs🇳🇴 · Konrad Tywoniuk🇳🇴
The steeply falling jet spectrum induces bias on the medium modifications of jet observables in heavy-ion collisions. To explore this bias, we develop a novel analytic framework to study the quenched jet spectrum, and its cumulative. We include many energy-loss-related effects, such as soft and hard medium induced emissions, broadening, elastic scattering, jet fragmentation, cone size, coherence effects, etc. We show that, different jet spectrum-based observables are connected, e.g., the nuclear modification, spectrum shift, and the quantile procedure. We present the first predictions for the nuclear modification factor and the quantile procedure with cone size dependence. As an example, we compare dijet and boson+jet events to unfold the spectrum bias effects. We improve quark-, and gluon-jet classification using arguments based on the cumulative. Besides pointing out its flexibility, we apply our framework with other energy loss models such as the hybrid weak-, strong-coupling.
Comments:
38 pages, 12 figures
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:
2103.14676 [pdf]
JHEP(2021)·36 citations
10
[Submitted on 27 Mar 2021] (cross-list from hep-th)
Entanglement Spheres and a UV-IR connection in Effective Field Theories
Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
We show that long-distance quantum correlations probe short-distance physics. Two disjoint regions of the latticized, massless scalar field vacuum are numerically demonstrated to become separable at distances beyond the negativity sphere, which extends to infinity in the continuum limit. The size of this quantum coherent volume is determined by the highest momentum mode supported in the identical regions, each of diameter $d$ . More generally, effective field theories (EFTs), describing a system up to a given momentum scale $Λ$ , are expected to share this feature -- entanglement between regions of the vacuum depends upon the UV-completion beyond a separation proportional to $Λ$ . Through calculations extended to three-dimensions, the magnitude of the negativity at which entanglement becomes sensitive to UV physics in an EFT (lattice or otherwise) is conjectured to scale as $\sim e^{- Λ d}$ , independent of the number of spatial dimensions. It is concluded that two-region vacuum entanglement at increasing separations depends upon the structure of the theory at increasing momentum scales. This phenomenon may be manifest in perturbative QCD processes.
Comments:
9 pages, 3 figures, 4 appendices (4 figures and 2 tables)
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2103.14999 [pdf]
PRL(2021)·40 citations
11
[Submitted on 28 Mar 2021] (cross-list from astro-ph.HE)
Constraints on the maximum mass of neutron stars with a quark core from GW170817 and NICER PSR J0030+0451 data
Ang Li🇨🇳 · Zhiqiang Miao🇨🇳 · Sophia Han🇺🇸 · Bing Zhang🇺🇸
We perform a Bayesian analysis of the maximum mass $M_{TOV}$ of neutron stars with a quark core, incorporating the observational data from tidal deformability of the GW170817 binary neutron star merger as detected by LIGO/Virgo and the mass and radius of PSR J0030+0451 as detected by \nicer. The analysis is performed under the assumption that the hadron-quark phase transition is of first order, where the low-density hadronic matter described in a unified manner by the soft QMF or the stiff DD2 equation of state (EOS) transforms into a high-density phase of quark matter modeled by the generic "Constant-sound-speed" (CSS) parameterization. The mass distribution measured for the $2.14 M_{⊙}$ pulsar, MSP J0740+6620, is used as the lower limit on $M_{TOV}$ . We find the most probable values of the hybrid star maximum mass are $M_{TOV} = 2.3 6_{- 0.26}^{+ 0.49} M_{⊙}$ ( $2.3 9_{- 0.28}^{+ 0.47} M_{⊙}$ ) for QMF (DD2), with an absolute upper bound around $2.85 M_{⊙}$ , to the $90%$ posterior credible level. Such results appear robust with respect to the uncertainties in the hadronic EOS. We also discuss astrophysical implications of this result, especially on the post-merger product of GW170817, short gamma-ray bursts, and other likely binary neutron star mergers.
Comments:
13 pages, 8 figures, 2 tables, to appear in ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2103.15119 [pdf]
ApJ(2021)·76 citations
12
[Submitted on 28 Mar 2021] (cross-list from hep-lat)
Lattice determination of $I = 0$ and 2 $π π$ scattering phase shifts with a physical pion mass
T. Blum🇺🇸 · P.A. Boyle🇺🇸 · M. Bruno🇨🇭 · N.H. Christ🇺🇸 · D. Hoying🇺🇸 · C. Kelly🇺🇸 · C. Lehner🇺🇸 · R.D. Mawhinney🇺🇸 · A.S. Meyer🇺🇸 · D.J. Murphy🇺🇸 · C.T. Sachrajda🇬🇧 · A. Soni🇺🇸 · T. Wang🇺🇸
Phase shifts for $s$ -wave $π π$ scattering in both the $I = 0$ and $I = 2$ channels are determined from a lattice QCD calculation performed on 741 gauge configurations obeying G-parity boundary conditions with a physical pion mass and lattice size of $3 2^{3} \times 64$ . These results support our recent study of direct CP violation in $K \to π π$ decay \cite{Abbott:2020hxn}, improving our earlier 2015 calculation \cite{Bai:2015nea}. The phase shifts are determined for both stationary and moving $π π$ systems, at three ( $I = 0$ ) and four ( $I = 2$ ) different total momenta. We implement several $π π$ interpolating operators including a scalar bilinear " $σ$ " operator and paired single-pion bilinear operators with the constituent pions carrying various relative momenta. Several techniques, including correlated fitting and a bootstrap determination of p-values have been used to refine the results and a comparison with the generalized eigenvalue problem (GEVP) method is given. A detailed systematic error analysis is performed which allows phase shift results to be presented at a fixed energy.
Comments:
v3: Add a subsection "Higher partial wave correction", and correct the unit of scattering length. 88 pages and 14 figures v2: 1). Add reference 29 as an example of pipi scattering calculation above 4mpi threshold. 2). Modify the wording on page 3 for the footage. 3). Correct the \sigma operator on page 17
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2103.15131 [pdf]
PRD(2021)·33 citations
13
[Submitted on 29 Mar 2021] (cross-list from hep-ph)
Electrical conductivity of strongly magnetized dense quark matter -- possibility of quantum hall effect
Jayanta Dey🇮🇳 · Aritra Bandyopadhyay🇨🇳 · Akash Gupta🇩🇪 · Naman Pujari🇮🇳 · Sabyasachi Ghosh🇮🇳
We have pointed out the possibility of quantum Hall effect or quantum patterns of transportation in a degenerate strongly magnetized quark matter, which might be expected inside a highly dense compact star. An anisotropic pattern of electrical conductivity and resistivity tensor in classical and quantum cases is explored by considering cyclotron motion and Landau quantization respectively. With increasing magnetic field, classical to quantum transitions are realized through enhanced/reduced resistivity/conductivity with jumping pattern. Considering QCD relaxation time scale of 10 fm, $e B \approx (1 - 4) m_{π}^{2}$ might be considered as strong magnetic field for massless and degenerate quark matter with quark chemical potential $μ \approx 0.2 - 0.4$ GeV. Beyond these threshold ranges of magnetic field, perpendicular motion of quarks might be stopped and 3 $\to$ 1 dimensionally reduced conduction picture might be established.
Comments:
23 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2103.15364 [pdf]
NPA(2023)·20 citations
14
[Submitted on 29 Mar 2021] (cross-list from hep-ph)
Nonequilibrium Dynamics of the Chiral Quark Condensate under a Strong Magnetic Field
Gastao Krein🇧🇷 · Carlisson Miller🇧🇷
Strong magnetic fields impact quantum-chromodynamics (QCD) properties in several situations; examples include the early universe, magnetars, and heavy-ion collisions. These examples share a common trait: time evolution. A prominent QCD property impacted by a strong magnetic field is the quark condensate, an approximate order parameter of the QCD transition between a high-temperature quark-gluon phase and a low-temperature hadronic phase. We use the linear sigma model with quarks to address the quark condensate time evolution under a strong magnetic field. We use the closed time path formalism of nonequilibrium quantum field theory to integrate out the quarks and obtain a mean-field Langevin equation for the condensate. The Langevin equation features dissipation and noise kernels controlled by a damping coefficient. We compute the damping coefficient for magnetic field and temperature values achieved in peripheral relativistic heavy-ion collisions and solve the Langevin equation for a temperature quench scenario. The magnetic field changes the dissipation and noise pattern by increasing the damping coefficient compared to the zero-field case. An increased damping coefficient increases fluctuations and time scales controlling condensate's short-time evolution, a feature that can impact hadron formation at the QCD transition. The formalism developed here can be extended to include other order parameters, hydrodynamic modes, and system's expansion to address magnetic field effects in complex settings as heavy-ion collisions, the early universe, and magnetars.
Comments:
23 pages, 7 figures. Invited article for a special issue in "Symmetry" devoted to "Advances in Chiral Quark Models", Jorge Segovia (ed.). Accepted version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2103.15665 [pdf]
Symmetry(2021)·12 citations
15
[Submitted on 29 Mar 2021] (cross-list from hep-ph)
Proton Mass Decomposition and Hadron Cosmological Constant
Keh-Fei Liu🇺🇸
Lattice results on sigma terms and global analysis of parton momentum fractions are used to give the quark and glue fractions of the proton mass and rest energy. The mass decomposition in terms of the trace of the energy-momentum tensor is renormalization group invariant. The decomposition of the rest energy from the Hamiltonian and the gravitational form factors are scheme and scale dependent. The separation of the energy-momentum tensor into the traceless part which is composed of the quark and glue parton momentum fractions and the trace part has the minimum scheme dependence. We identify the glue part of the trace anomaly $⟨ H_{β} ⟩$ as the vacuum energy from the glue condensate in the vacuum. From the metric term of the gravitational form factors, which is the stress part of the stress-energy-momentum tensor, we find that the trace part of the rest energy, dominated by $⟨ H_{β} ⟩$ , gives a {\it constant} restoring pressure which balances that from the traceless part of the Hamiltonian to confine the hadron, much like the cosmological constant Einstein introduced for a static universe. From a lattice calculation of $⟨ H_{β} ⟩$ in the charmonium, we deduce the associated string tension which turns out to be in good agreement with that from a Cornell potential which fits the charmonium spectrum.
Comments:
Version to be published in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2103.15768 [pdf]
PRD(2021)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE