Study Of Single-proton Knockout Reaction On Neutron-rich Carbon Isotopes

Knockout reaction is one of important experimental methods to study nuclear structure,especially for unstable nuclei.Systematic study with one-nucleon knockout reaction in intermediate energy region（～80 Me V/u）shows that the ratios of experimental reaction cross-section and theorical one,R_s,depend on isospin asymmetryΔS significantly,and it could be far smaller than 1 in the case of knockout of deeply bound nucleon.This difference between experiment and theory is usually considered as the result of unexpected residual interaction which is not included in nuclear structure model.However,some of other study suggest that the inapplicability of Glauber model in intermediate energy region could be the reason of this difference.Therefore,a systematic study in higher energy region and a comparison with study of intermediate energy region are necessary.The experimental study of knockout reaction,especially systematic experimental study of knockout of deeply bound nucleon in higher energy region are still lacking nowadays.Therefore,an experimental study of knockout reaction of carbon isotope ^12-16C with carbon target has been conducted at External Target Facility（ETF）,Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring（HIRFL-CSR）for the contribution of knockout reaction study in higher energy region.Secondary beams with ^12-16C are produced and identified with radioactive isotope beam line RIBLL2,and the products of knockout reaction are identified with the ETF.With the analysis of experimental data,we obtained the cross sections of single-proton knockout reaction of ^12-16C and extracted the experimental longitudinal momentum of the residues.The theorical cross sections of single-proton knockout reaction of ^12-16C were calculated with Glauber model and nuclear structure models such as SM、GSM and NCSM,and the R_shave been obtained.The result of this work confirmed that thehas significant dependence with isospin asymmetry in heavy ion induced single-proton knockout reactions at higher energy region（～240Me V/u）,which is consistent with the result observed at intermediate energy region（～80Me V/u）,which demonstrates that R_s are robust with beam energy and the dependence of R_sonΔS is not caused by the selection of beam energy,support the reliability of knockout reaction method.