Mass spectrum measurement in (p,2p) reaction on C, Al, Cu, Pb nuclei at proton energy of 500 MeV

Mass spectra of the (p, 2p) reaction on nuclei C, Al, Cu and Pb at the proton energy 500 MeV were measured on double-arm nonmagnetic scintillation spectrometer (solid angle 0.2 sr, mass resolution 4 MeV), which is located at the TRIUMF cyclotron (Canada). Observable anomalies in these spectra can be stipulated by formation of two-nucleon resonance states. Measured two-particle coincidence spectra permitted us to get mass spectra of two protons at the condition of accumulation of all correlated pairs of pp-events in a wide range of registration angles and at the selection only of complanar pairs in a narrow angle range (∼140). Spectra of the mass interval from 1954 MeV/c2 to 2220 MeV/c2 at mass step 3.528 MeV/c2 for each nucleus and also the total (summarized on all nuclei) spectrum of complanar protons have been obtained. Anomalies with the following mass values are observed in this spectrum: 2008, 2017, 2028, 2046, 2067, 2087, 2096 and 2106 MeV/c2, they were measured with the error ±4 MeV/c2. We suggest that the formation of dinucleon resonances, anomalies with masses 2008, 2028, 2067, 2087 and 2096 MeV/c2 is in the rotation bands of NN-resonance. The second group of resonances with masses 2017, 2046 and 2106 MeV/c2 is the rotation band of NNπ-resonances. (author)