Nuclear Theory·nucl-th
12 papers—6 primary·6 cross-listed
Chiral effective field theory is being developed into a precision tool for low-energy nuclear physics. I review the state of the art in the two-nucleon sector, discuss applications to few-nucleon systems and address challenges that will have to be faced over the coming years.
The deuteron form factors are calculated using two model wave functions obtained from the 2007 CST high precision fits to scattering data. Included in the calculation are a new class of isoscalar interaction currents which are automatically generated by the nuclear force model used in these fits. If the nuclear model WJC2 is used, a precision fit (/datum ) to the Sick Global Analysis (GA) of all elastic scattering data can be obtained by adjusting the unknown off-shell nucleon form factors (discussed before) and (introduced in this paper), and predicting the high behavior of the neutron charge form factor well beyond the region where it has been measured directly. Relativistic corrections, isoscalar interaction currents, and off-shell effects are defined, discussed, and their size displayed. A rationale for extending elastic scattering measurements to higher is presented.
Xiao-Tao He · Shu-Yong Zhao · Zhen-Hua Zhang · Zhong-Zhou Ren
The multi-particle states and rotational properties of two-particle bands in No are investigated by the cranked shell model (CSM) with pairing correlations treated by a particle-number conserving (PNC) method. For the first time, the rotational bands on top of two-particle and states and the pairing reduction are studied theoretically in No. The experimental excitation energies and moments of inertia for the multi-particle state are reproduced well by the calculation. Better agreement with the data are achieved by including the high-order deformation which leads to enlarged and deformed shell gaps. The rise of the in these two-particle bands compared with the ground-state band is attributed to the pairing reduction due to the Pauli blocking effects.
Bengt Friman🇩🇪 · Wolfram Weise🇩🇪
The equation of state (EoS) of neutron star matter, constrained by the existence of two-solar-mass stars and gravitational wave signals from neutron star mergers, is analysed using the Landau theory of relativistic Fermi liquids. While the phase diagram of dense and cold QCD matter is still open for scenarios ranging from hadronic to quark matter in the center of neutron stars, a Fermi-liquid treatment is motivated by a microscopic approach starting from a chiral nucleon-meson field theory combined with nonperturbative functional renormalization group methods. In this scheme effects of multipionic fluctuations and repulsive nuclear many-body correlations suggest that the transition to chiral symmetry restoration is shifted to densities above those typically encountered in the neutron star core. Under such conditions a Fermi-liquid description in terms of nucleon quasiparticles appears to be justified. The leading Landau parameters are derived and discussed. Our results are contrasted with a well-known Fermi liquid, namely liquid He.
Fernando G. Gardim🇧🇷 · Giuliano Giacalone🇫🇷 · Matthew Luzum🇧🇷 · Jean-Yves Ollitrault🇫🇷
Collisions between heavy atomic nuclei at ultra-relativistic energies are carried out at particle colliders to produce the quark-gluon plasma, a state of matter where quarks and gluons are not confined into hadrons, and colour degrees of freedom are liberated. This state is thought to be produced as a transient phenomenon before it fragments into thousands of particles that reach the particle detectors. Despite two decades of investigations, one of the big open questions is to obtain an experimental determination of the temperature reached in a heavy-ion collision, and a simultaneous determination of another thermodynamic quantity, such as the entropy density, that would give access to the number of degrees of freedom. Here we obtain the first such determination, utilizing state-of-the-art hydrodynamic simulations. We define an effective temperature, averaged over the space-time evolution of the medium. Then, using experimental data, we determine this temperature, the corresponding entropy density and speed of sound in the matter created in lead-lead collisions at the Large Hadron Collider. Our results agree with first-principles calculations from lattice quantum chromodynamics and confirm that a deconfined phase of matter is indeed produced.
C. G. Payne🇩🇪 · S. Bacca🇩🇪 · G. Hagen🇺🇸 · W. Jiang🇺🇸 · T. Papenbrock🇺🇸
Coherent elastic neutrino scattering on the 40Ar nucleus is computed with coupled-cluster theory based on nuclear Hamiltonians inspired by effective field theories of quantum chromodynamics. Our approach is validated by calculating the charge form factor and comparing it to data from electron scattering. We make predictions for the weak form factor, the neutron radius, and the neutron skin, and estimate systematic uncertainties. The neutron-skin thickness of 40Ar40 is consistent with results from density functional theory. Precision measurements from coherent elastic neutrino-nucleus scattering could potentially be used to extract these observables and help to constrain nuclear models.
Tomoya Naito · Daisuke Ohashi · Haozhao Liang
We proposed in Ref. [arXiv:1812.09285v2] a way to improve energy density functionals in the density functional theory based on the combination of the inverse Kohn-Sham method and the density functional perturbation theory. In this proceeding, we mainly focus on the results for the and atoms.
N. Burtebayev · Sh. Hamada · Awad A. Ibraheem · K. Rusek · M. Wolinska-Cichocka · J. Burtebayeva · N. Amangeldi · Maulen Nassurlla · Marzhan Nassurlla · A. Sabidolda
In this study, the angular distribution of the 16O+10B elastic scattering was measured at Elab (16O)= 24 MeV. In addition to our experimental data, this nuclear system was theoretically analyzed at different energies to study the dynamics of scattering for this system. The data were analyzed within the framework of the double-folding optical potential model.
Yuki Fujimoto🇯🇵 · Kenji Fukushima🇯🇵 · Wolfram Weise🇯🇵
This study is performed with the aim of gaining insights into the possible applicability of the quark-hadron continuity concept, not only in the idealized case of three-flavor symmetric quark matter, but also for the transition from neutron matter to two-flavor quark matter. A key issue is the continuity between neutron superfluidity and a corresponding superfluid quark phase produced by -quark pairing. Symmetry arguments are developed and relevant dynamical mechanisms are analyzed. It is pointed out that the superfluidity in dense neutron matter has a direct analogue in the pairing of -quarks in two-flavor quark matter. This observation supports the idea that the quark-hadron continuity hypothesis may be valid for such systems. Possible implications for neutron stars are briefly discussed.
In the present work, we develop a causal theory of relativistic non-ideal fluids up to the second order in the Eckart frame using gradient expansion scheme. Keeping the spirit of Mueller-Israel-Stewart formalism, the general forms of bulk viscosity, shear viscosity tensor and the heat flow vector are presented. Since each of the flux quantities explicitly carry curvature terms, we show that our formalism finds application in astrophysics in particular in the strong gravity regime. We elucidate two such applications namely in viscous thick accretion disks also known as Polish doughnuts and in addressing non-rotating equilibrium configuration, like neutron stars.
Mateusz Cierniak🇵🇱 · Tobias Fischer🇵🇱 · Niels-Uwe Bastian🇵🇱 · Thomas Klaehn🇺🇸 · Marc Salinas🇺🇸
We construct a set of equations of state (EoS) of dense and hot matter with a 1st order phase transition from a hadronic system to a deconfined quark matter state. In this two-phase approach, hadrons are described using the relativistic mean field theory with different parametrisations and the deconfined quark phase is modeled using vBag, a bag-type model extended to include vector interactions as well as a simultaneous onset of chiral symmetry restoration and deconfinement. This feature results in a non-trivial connection between the hadron and quark EoS, modifying the quark phase beyond its onset density. We find that this unique property has an impact on the predicted hybrid (quark core) neutron star mass--radius relations.
Alexei Bazavov🇺🇸 · Simon Dentinger🇩🇪 · Heng-Tong Ding🇨🇳 · Prasad Hegde🇮🇳 · Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Edwin Laermann🇩🇪 · Anirban Lahiri🇩🇪 · Swagato Mukherjee🇺🇸 · Hiroshi Ohno🇯🇵 · Peter Petreczky🇺🇸 · Rishabh Thakkar🇮🇳 and 4 other authors
We present lattice QCD results for mesonic screening masses in the temperature range 140 MeV 2500 MeV. Our calculations were carried out using (2+1)-flavors of the Highly Improved Staggered Quark (HISQ) action, with a physical value for the strange quark mass and two values of the light quark mass corresponding to pion masses of 160 MeV and 140 MeV. Continuum-extrapolated results were obtained using calculations with a variety of lattice spacings corresponding to temporal lattice extents . We discuss the implications of these results for the effective restoration of various symmetries in the high temperature phase of QCD, as well as the approach toward the perturbative limit.
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