A direct probe of the in-medium pn scattering cross section

Yong, Gao‐Chan; Zuo, Wei; Zhang, Xun-Chao

doi:10.1016/j.physletb.2011.10.020

Cited by 15 publications

(21 citation statements)

References 53 publications

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“…6 the double ratio of observable, effects of in-medium N N cross section are still very obvious. Besides theoretical efforts [27] and advanced method such as photon emission in heavy-ion collisions [30], we also simulated the double ratio of π − /π + from two reaction systems (with the same mass number of system but different isotopes) 132 Sn + 124 Sn and 128 P m + 128 P m. Interestingly, from Fig. 7 one sees that effects of symmetry energy are kept but the effects of in-medium N N elastic scattering cross section are almost fully cancelled out.…”

Section: Resultsmentioning

confidence: 99%

Effects of nuclear symmetry energy and in-mediumNNcross section in heavy-ion collisions at beam energies below the pion production threshold

2014

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Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck(IBUU04) transport model, we explored effects of in-medium N N elastic scattering cross section and nuclear symmetry energy on the sub-threshold pion production in 132 Sn + 124 Sn reaction. We find that with decrease of incident beam energy, effects of in-medium N N elastic scattering cross section on the π − /π + ratio are larger than that of the symmetry energy although the latter may be also larger. While keeping the effect of symmetry energy, the double ratio of π − /π + from neutron-rich and neutron-poor reaction systems (with the same mass number of system) 132 Sn + 124 Sn and 128 P m + 128 P m almost fully cancels out the effects of in-medium N N elastic scattering cross section.

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Section: Resultsmentioning

confidence: 99%

Effects of nuclear symmetry energy and in-mediumNNcross section in heavy-ion collisions at beam energies below the pion production threshold

2014

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“…It is noticed from Fig. 6 that the used in-medium neutron-proton scattering cross section fits the experimental hard photon measurements quite well [50]. Before studying the π − /π + ratio, it is instructive to first see the production of charged pion meson in central Au + Au reaction at 400 MeV/nucleon beam energy.…”

Section: The Ibuu Transport Modelmentioning

confidence: 85%

“…With great efforts, the nuclear symmetry energy and its slope around saturation density of nuclear matter from 28 analysis of terrestrial nuclear laboratory experiments and astrophysical observations have been roughly pinned down [15], while recent interpretations of the FOPI and FOPI-LAND experimental measurements by different groups made the symmetry energy at supra-saturation densities fall into chaos [16][17][18][19][20][21][22]. It does not seem to be clarified why the nuclear symmetry energy at supra-saturation densities is so uncertain, maybe the effects of pion inmedium effects [23][24][25], the isospin dependence of inmedium nuclear strong interactions [26], the short-range tensor force [27,28] are some factors.…”

Section: Introductionmentioning

confidence: 99%

Cross-checking the symmetry energy at high densities

Yong

2016

Phys. Rev. C

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By considering both the effects of the nucleon-nucleon short-range correlations and the isospindependent in-medium inelastic baryon-baryon scattering cross section in the transport model, two unrelated Au + Au experimental measurements at 400 MeV/nucleon beam energy are simultaneously analyzed, a mildly soft symmetry energy (L(ρ0) = 37 MeV) at supra-saturation densities is obtained. This result is compatible with the recent result in Phys. Rev. C 92, 064304 (2015) by comparing the available data on the electric dipole polarizability with the theoretical predictions.

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“…. It thus provides more opportunities and enhances our confidences to study the symmetry energy although there are still many uncertain factors, such as the effects of pion potential [15,16], the isospin dependence of inmedium nuclear strong interactions [17], the short-range tensor force [18,19] and the π − N − ∆ dynamics [20][21][22].…”

Section: Motivationsmentioning

confidence: 99%

Effect ofΔpotential on theπ−/π+ratio in heavy-ion collisions at intermediate energies

2015

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Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck(IBUU) transport model, effects of ∆ resonance potential on the free n/p and π − /π + ratios in the central collision of 197 Au + 197 Au at beam energies of 200 and 400 MeV/A are studied. It is found that the effect of ∆ potential on the ratio of pre-equilibrium free n/p is invisible. The effect of ∆ isovector potential on the kinetic energy integrating ratio of π − /π + may be observable only at lower incident beam energies and with stiffer symmetry energy. The strength of the ∆ isoscalar potential affects the height of the π − /π + ratio around the Coulomb peak but does not affect the kinetic energy integrating ratio of π − /π + . In heavy-ion collisions at intermediate energies, relating to the question of non-conservation of energy on ∆ or π productions, one can replace the ∆ potential by nucleon isoscalar potential especially a soft symmetry energy is employed. I. MOTIVATIONSIn recent years, the research of the density dependent symmetry energy is still one of the hot topics in nuclear physics and astrophysics communities. This is simply because the symmetry energy governs many nuclear and astrophysical phenomena, such as the cooling of neutron stars [1], the mass-radius relations of neutron stars [2], the study of Gravitational waves [3], properties of nuclei involved in r-process nucleosynthesis [4], and observables in heavy-ion collisions at intermediate energies [5,6]. While significant progress has been made in constraining the symmetry energy around saturation density [6][7][8][9], it is rather uncertain at supra-saturation densities. . It thus provides more opportunities and enhances our confidences to study the symmetry energy although there are still many uncertain factors, such as the effects of pion potential [15,16], the isospin dependence of inmedium nuclear strong interactions [17], the short-range tensor force [18,19] and the π − N − ∆ dynamics [20][21][22].It is noted that the sensitivities of the π − /π + ratio to the symmetry energy shown in Ref. [16,20] is quite different from that shown in Ref. [15]. The discrepancies observed among the results of different models may be * Electronic address: yonggaochan@impcas.ac.cn because the latter uses a momentum-dependent nucleon symmetry potential while the previous two studies use a momentum-independent nucleon symmetry potential. The momentum-dependent nucleon symmetry potential could increase the sensitivity of dense neutron to proton ratio (thus the π − /π + ratio) to the symmetry energy [23]. While in this study, we use a modified symmetry potential which including the effects of the short-range correlations of neutron and proton [24]. The short-range correlations of neutron and proton reduce the kinetic symmetry energy, the strength of the modified symmetry potential is thus increased [24]. The effects of such modified symmetry potential on the π − /π + ratio may be also enlarged. In the following studies, we confirmed the above deduction.In Refs. [20][21][22] it is argued that due t...

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A direct probe of the in-medium pn scattering cross section

Cited by 15 publications

References 53 publications

Effects of nuclear symmetry energy and in-mediumNNcross section in heavy-ion collisions at beam energies below the pion production threshold

Effects of nuclear symmetry energy and in-mediumNNcross section in heavy-ion collisions at beam energies below the pion production threshold

Cross-checking the symmetry energy at high densities

Effect ofΔpotential on theπ−/π+ratio in heavy-ion collisions at intermediate energies

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