Nuclear Astrophysics Experiments in Collaboration with Ruhr University

This paper reports on two nuclear astrophysics experiments performed in collabora- tion with Ruhr University. In a 12C＋2C fusion reaction, the 12C（12C, a）20e and 12C（12C, p）23Na reactions were studied in the energy range of E = 2.10 MeV to 4.75 MeV using -y-ray spectroscopy. The deduced astrophysical S（E）＊ factor exhibited a new, strong resonance at E -= 2.14 MeV, which lay at the high-energy tail of the Gamow peak. The resonance increased the reaction rate of the ^-channel by a factor of five near T = 8 ~ l0s K. The electron screening in d（d, p）t was stud- ied for a series of deuterated metal, insulator and semiconductor targets. Compared with the measurements performed with a gaseous D2 target, a large effect was observed in most metals, while a comparatively small effect was found in the insulators and semiconductors. Subsequently the temperature dependence of the electron screening in the d（d, p）t reaction was studied for the deuterated metals Pt and Co. Enhanced electron screening decreased with increasing tempera- ture. These data represent the first observations of the temperature dependence of a nuclear cross section.

High energy and high brightness laser compton backscattering gamma-ray source at IHEP

Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS)gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful researchplatform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantumelectrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO_(2) laser system are employed. All the triggersignals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure thetemporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to alignthe electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, thephoton-nuclear physics, nuclear astrophysics and some basic QED phenomena.

Neutron and Alpha Structure in Neutron Deficient Nuclei in Astrophysics

The paper includes discussions on the important role of neutron and alpha configurations in proton-rich nuclei in nuclear astrophysics in terms of nucleosynthesis under extremely high-temperature hydrogenburning conditions. The νp-process, which is supposed to take place at the very early epoch of type II supernovae, has considerable neutrons and alphas together with protons. The alpha-induced reactions on proton-rich unstable nuclei in the light mass regions is expected to play a crucial role, but very few of them were investigated well yet because of the experimental difficulties. Specifically, I report our recent experimental effort for the breakout process from the pp-chain region,~7Be(α, γ)^(11)C(α,p)^(14)N under the νp-process. The neutron-induced reactions on proton-rich nuclei, which is even more a challenging subject, were investigated previously for very few nuclei. One possible experimental method is the Trojan Horse Method(THM). We successfully have applied THM to the ^(18)F(n,α)^(14)N reaction study with an unstable beam of ^(18)F.

Radiative^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rate in the potential cluster model

Within the framework of the modified potential cluster model with forbidden states,the total cross-sections of radiative n^(9)Be capture to the ground and five low-lying excited states are calculated at energies from 10^(-2)eV up to 5 MeV.The thermal cross-section σ_(th)=8.35mb is in good agreement with experimental data.We considered five resonances at the excitation energies E_(x)from 7.371 MeV up to 10.570 MeV corresponding to the following states with J^(π)(E_(x),MeV):3^(-)(7.371),2^(+)(7.542),3^(+)(9.4),2^(+)(9.56),and 3^(-)(10.570).The partial and total ^(9)Be(n,γ0+1+2+3+4+5)^(10)Be reaction rates are calculated at temperatures from 0.001 to 10 T_(9).Contrary to the available data,we propose that the rise in the reaction rate near factor five at T_(9)>1 is mainly due to the first 3^(-)(E_(R)=0.559 MeV)resonance.We foresee this contrast as arising from different model approaches.

Observatory science with eXTP

In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry(eXTP) mission for studies related to Observatory Science targets. These include flaring stars, supernova remnants, accreting white dwarfs, low and high mass X-ray binaries, radio quiet and radio loud active galactic nuclei, tidal disruption events, and gamma-ray bursts. eXTP will be excellently suited to study one common aspect of these objects: their often transient nature. Developed by an international Consortium led by the Institute of High Energy Physics of the Chinese Academy of Science, the eXTP mission is expected to be launched in the mid 2020s.

Effects of relativistic parameter sets on tidal deformabilities and f-mode oscillations of neutron stars

The implications of relativistic parameter sets established at saturation density on the tidal deformabilities and f-mode oscillations of neutron stars(NSs)are examined using constraints from the gravitational wave(GW)event GW170817 and NICER.According to our findings,the isovector saturation parameters have a greater impact on the radii and tidal deformabilities of NSs than the isoscalar saturation parameters.Our analysis also examines the impact of saturation properties on f-mode frequencies and finds that f-mode frequencies with 1.4 M⊙(solar mass)are roughly between 1.95 and 2.15 kHz.These findings could be confirmed by future advanced GW detectors.A good linear parameter-independent correlation between f-mode frequencies inferred from saturation parameters in the entire region is also observed,and we attempt to fit an updated version of this universal relationship.Furthermore,we used chiral effective theory(χEFT)together with the multi-messenger astronomy constraints to further reinforce the rationality of the conclusions we have reached.

Short-range correlation effects in neutron star's radial and non-radial oscillations

In this study,we determine the influence of the nucleon-nucleon short range correlation(SRC)on static spherically symmetric neutron stars(NSs)from the perspectives of radial and nonradial oscillations for the first time.We revise the equation of state and coupling parameters in the relativistic mean field theory after considering the SRC effect,and select the hyperon coupling parameters as the SU(3)model.For the non-radial oscillations,the SRC effect decreases the f-mode frequency by 0.2~0.3 kHz.For the radial oscillations,it decreases the fundamental radial frequency f_(1) by 0.75~0.85 kHz.Additionally,we refit the linear relationship between the average density and f-mode frequency for SRC.Combining the characteristics of the radial and non-radial frequencies,we provide a view of inferring the maximum mass of NSs.Owing to the characteristics of the SRC influence on the radial frequency,we expect that the SRC can be tested by future observation and can also be used as a probe for the structure inside NSs.