Nuclear Theory·nucl-th

Friday·June 24, 2022

8 papers—5 primary·3 cross-listed

01
[Submitted on 23 Jun 2022]
Complete experiment problem for photoproduction of two pseudoscalar mesons on a nucleon in a truncated partial-wave analysis
A. Fix🇷🇺 · I. Dementjev🇷🇺
It is shown that within a truncated partial wave analysis for photoproduction of two pseudoscalar mesons, it is possible to halve the number of independent partial amplitudes by taking into account parity conservation. In addition, within the framework of the proposed formalism, one can rather easily resolve the double discrete ambiguity arising from the symmetry under complex conjugation of the helicity amplitudes. This leads to essential simplifications of the complete experiment problem, at least as far as mathematical aspects are concerned.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2206.11432 [pdf]
PRC(2022)·1 citation
02
[Submitted on 23 Jun 2022]
Charmonium dissociation at high baryon chemical potential
Bo Tong🇨🇳 · Baoyi Chen🇨🇳
We study the charmonium dissociation in the hot medium with finite baryon chemical potential $μ_{B}$ . Charmonium bound states are dissociated in the medium by the color screening effect and the random scatterings with thermal partons, which are included in the real and imaginary parts of the potential respectively. $J / ψ$ fraction in the $c c ˉ$ pair defined to be the quantum overlap between the wave package and the wave function of $J / ψ$ eigenstate decreases with time due to the complex potentials. When $μ_{B}$ is large compared with the medium temperature, the Deybe mass is increased evidently. We consider $μ_{B}$ -dependent Deybe mass in both real and imaginary parts of the potential to calculate the $J / ψ$ survival probability in the static medium and the Bjorken medium. $J / ψ$ survival probability is reduced evidently by the $μ_{B}$ effect at low temperatures available in the medium produced in Beam Energy Scan experiments, while this effect becomes not apparent at high temperatures.
Comments:
6 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2206.11442 [pdf]
PRC(2022)·2 citations
03
[Submitted on 23 Jun 2022]
Formation of large chunk of nuclear matter in heavy-ion collisions
Gao-Chan Yong🇨🇳
In terrestrial laboratory with existing accelerators, the maximum multinucleon system produced so far is limited to that with total nucleon number being less than the sum of two colliding nuclei. Such situation may hinder our studies on the properties of nuclear many-body system. Here a way of producing large multinucleon system via multi-nucleus collision device Collider Plus in terrestrial laboratory is proposed. It is shown that large chunk of nucleonic matter can be produced through nuclear ternary fusion reactions at lower beam energies and also large block of dense matter can be formed via ternary collisions of heavy nuclei at intermediate energies. These investigations may shed lights on the studies of the synthesis of superheavy elements and the properties of bulk superdense nuclear matter.
Comments:
5 pages, 5 figures, Phys. Lett. B, in production
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2206.11446 [pdf]
PLB(2022)·0 citations
04
[Submitted on 23 Jun 2022]
Mass radius and mechanical properties of the proton via strange $ϕ$ meson photoproduction
Xiao-Yun Wang🇨🇳 · Chen Dong🇨🇳 · Quanjin Wang🇨🇳
In this work, the cross sections of $ϕ$ photoproduction are systematically investigated with the two gluon exchange model and the pomeron model. The results obtained show that the theoretical values of the two models agree well with the experimental data. Since the mass radius and mechanical properties of the proton are encoded in the scalar gravitational form factor of the momentum energy tensor, based on the differential cross sections of $ϕ$ photoproduction at near-threshold predicted by the two gluon exchange model, the average mass radius of the proton is derived as $⟨ r^{2} ⟩_{m} = 0.78 \pm 0.06$ fm. As a comparison, we directly extract the proton mass radius from the experimental data of $ϕ$ photoproduction to obtain an average value of $0.80 \pm 0.05$ fm, which is very close to the result given by the two gluon exchange model. Taking a similar approach, we extracted the average value of $m_{D}$ to obtain the distribution of the pressure and shear force contributed within the proton, and compared the results with other groups. The results of this paper may provide necessary theoretical information for the subsequent in-depth study of the internal structure and properties of proton.
Comments:
11 pages, 13 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.11644 [pdf]
PRD(2022)·20 citations
05
[Submitted on 23 Jun 2022]
Tensor polarization and the dissipative damping of vector meson in QCD Medium
Feng Li🇨🇳 · Shuai Y. F. Liu🇨🇳
Unexpectedly large and puzzling spin alignment, and thus tensor polarization, of vector mesons has been observed in heavy-ion collisions. Given that tensor polarization represents a fluctuation of spin, we derive, for the first time, a fluctuation-dissipation relation for tensor polarization, where the polarization is proportional to first-order hydrodynamic gradients (e.g., the shear-stress tensor), with dissipative coefficients depending on the particle's damping properties, as characterized by its spectral function. Employing relativistic hydrodynamics at finite density, we find that dissipative contributions can generate substantial spin alignment. We provide illustrative examples (by tuning one coefficients $α_{sh}$ ) that generate a beam energy, $p_{T}$ , and centrality dependence of spin alignment resembling those observed in experiments, offering insights into these puzzling phenomena and demonstrating its potential as a ``spectrometer" for in-medium vector mesons.
Comments:
10 pages, 6 figures. v6: Added one new figure (Fig. 6) for more on centrality dependence. v5: Major update (added phenomenological studies using hydrodynamics at various beam energies, centralities, etc.)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2206.11890 [pdf]
45 citations

Affiliations

first authorsco-authorsvia INSPIRE

Complete experiment problem for photoproduction of two pseudoscalar mesons on a nucleon in a truncated partial-wave analysis

Charmonium dissociation at high baryon chemical potential

Formation of large chunk of nuclear matter in heavy-ion collisions

Mass radius and mechanical properties of the proton via strange ϕ meson photoproduction

Tensor polarization and the dissipative damping of vector meson in QCD Medium

Affiliations

Mass radius and mechanical properties of the proton via strange $ϕ$ meson photoproduction