Experimental study of (p, 2p) reactions at 392 MeV on 12C, 16O, 40Ca and 208Pb nuclei leading to low-lying states of residual nuclei

We have measured the differential cross-sections and analyzing powers for ($p,2p$) reactions at an incident energy of 392 MeV on $^{12}$C, $^{16}$O, $^{40}$Ca, and $^{208}$Pb nuclei, leading to discrete states of the residual nuclei. The data are compared with two kinds of distorted-wave impulse approximation (DWIA) calculations, a standard calculation using a global optical potential and a calculation using wave functions generated in a relativistic Hartree model. The spectroscopic factors deduced from these two calculations agree with those determined in ($e,e'p$) studies mostly within 15% in the case of the lighter three target nuclei. However, those for the $^{208}$Pb target are overestimated compared with the ($e,e'p$) results. In the heavy target case, the DWIA results are very sensitive to the radius parameter of the bound-state potential and thus a careful treatment is required. Regarding the analyzing powers of the present measurement, we confirmed that the $j$-dependence is sufficient for practical spectroscopic use.

The (p,2p) reaction in finite range relativistic distorted-wave impulse approximation

The [Formula: see text] reaction on [Formula: see text] at incident proton energy of 300[Formula: see text]MeV is examined in the formalism of finite-range relativistic distorted-wave impulse approximation (FR-RDWIA). In comparison to conventional t-matrix model of Love–Franey, a new form of nucleon–nucleon t-matrix effective interaction is derived at 300[Formula: see text]MeV using Reid soft core potentials for isotopic spin one and taking into account the finite-range effects in the [Formula: see text] interaction at knockout vertex. In comparison to the conventional finite range nonrelativistic and relativistic formalism, the present formalism with a new version of [Formula: see text] t-matrix is effectively reproducing the shape of cross-section energy distributions for [Formula: see text], [Formula: see text] and [Formula: see text] states for asymmetric angle pair of [Formula: see text]–[Formula: see text]. Discrepancies between the experimental cross-section data and finite range theoretical calculations at [Formula: see text][Formula: see text]MeV are reasonably resolved in the present approach. Without any adjustable parameter of bound state, the obtained spectroscopic factors are in reasonably good agreement with the relativistic and nonrelativistic theoretical predictions by [Formula: see text], [Formula: see text] and [Formula: see text] analysis.

Λ-HYPERNUCLEAR PRODUCTION IN $(K_{{\rm{stop}}}^-, \pi)$ REACTIONS

In the present contribution, we report on calculation of the Λ-hypernuclear production induced by the stopped kaon K-. We performed the calculation within the framework of the distorted wave impulse approximation and used chirally motivated transition amplitudes for the microscopic description of the elementary kaon-nucleon process. The sensitivity of the model to several effects was tested with a special attention paid to the impact caused by variations of the initial kaon and final state pion wave functions. The calculated production rates are reported for target nuclei from Lithium to Oxygen.

WITNESSING THE HADRONIC COLLISION EVENTS AT CLOSE QUARTERS

It is seen that in the three body final state of a nucleon knockout reaction the residual nucleus not only bears testimony to the dynamics of the knocked out nucleon before the event but also can testify the happening at the time of the hard collision event. This arises mainly because of the distorting optical potentials of the residual nucleus with the knockout partners. In 40Ca(p, 2p) knockout reaction the optical distortion effects are large enough to be able to differentiate between strong peripheral bruising or the deep interpenetration of the two protons at the time of knockout. Similar effect is witnessed in the proton knockout using pions. Many stronger evidences of the effect of varying behaviour of the knockout vertex exist in the nucleon cluster knockout reactions which were only viewed as unexplained large anomalies. Evidences are provided where the different short distance behaviour of the knockout vertex t -matrix effective interaction produced huge differences in the finite range (FR) distorted wave impulse approximation (DWIA) predictions of various knockout reactions. These observations enhance the possibility of observing the multiquark objects (dibaryons, pentaquark eta.) through nucleon knockout reactions if they are produced at the knockout vertex by the incident hadron beam.

FORMATION OF DEEPLY-BOUND K-pp STATE IN 3He(IN-FLIGHT K-, n) REACTION SPECTRUM

The formation of a deeply-bound K-pp state by the 3 He (in-flight K-, n) reaction is investigated theoretically in a distorted-wave impulse approximation using the Green's function method. The expected inclusive and semi-exclusive spectra at pK- = 1.0 GeV / c and θn = 0∘ are calculated for the forthcoming J-PARC E15 experiment. We discuss these spectra with some K--"pp" optical potentials, taking into account the energy-dependence of the imaginary part of the potentials by a phase space suppression factor.

3He(K-, n) REACTION SPECTRUM NEAR THE $\bar KN \to \pi \sum $ DECAY THRESHOLD AND THE DEEPLY-BOUND K-pp STATE

The formation of a deeply-bound K-pp state by the 3 He ( in - flight K-, n) reaction is investigated theoretically in a distorted-wave impulse approximation using the Green's function method. The expected inclusive and semi-exclusive spectra at pK- = 1.0 GeV / c and θn = 0° are calculated for the forthcoming J-PARC E15 experiment. We discuss these spectra with some K--"pp" optical potentials, taking into account the energy-dependence of the imaginary part of the potentials by a phase space suppression factor.

FORMATION OF THE DEEPLY-BOUND K−pp STATE IN THE 3He(IN-FLIGHT K−, n) SPECTRUM

The formation of a deeply-bound K−pp state by the 3 He (in-flight K−, n) reaction is investigated theoretically in a distorted-wave impulse approximation using the Green's function method. The expected inclusive and semi-exclusive spectra at pK− = 1.0 GeV / c and θn = 0° are calculated for the forthcoming J-PARC E15 experiment. We discuss these spectra with some K−-“pp” optical potentials, taking into account the energy-dependence of the imaginary part of the potentials by a phase space suppression factor.