One-neutron knockout reaction of 17C on a hydrogen target at 70 MeV/nucleon

Abstract

First experimental evidence of the population of the first 2 − state in 16 C above the neutron threshold is obtained by neutron knockout from 17 C on a hydrogen target. The invariant mass method combined with in-beam γ-ray detection is used to locate the state at 5.45(1) MeV. Comparison of its populating cross section and parallel momentum distribution with a Glauber model calculation utilizing the shell-model spectroscopic factor confirms the core-neutron removal nature of this state. Additionally, a previously known unbound state at 6.11 MeV and a new state at 6.28(2) MeV are observed. The position of the first 2 − state, which belongs to a member of the lowest-lying p-sd cross shell transition, is reasonably well described by the shell-model calculation using the WBT interaction.

Characteristic α and He6 decays of linear-chain structures in C16Baba1, Kimura2 2018Phys. Rev. C1910240View full textAdd to dashboardCite

“…Figure 6 shows the spectrum of the negative-parity states. Only two states (2 − and 5 − ), which are described by open boxes in the figure, were observed with the definite spin-parity assignments [19,35]. Our calculation shows the yrast band which is built on the 2 − 1 state located at 6.0 MeV, and the 2 − 1 and 5 − In the case of negative-parity, the linear-chain configuration generates two different types of rotational bands.…”

“…For positive parity, we show the member (color online) The negative-parity energy levels up to J π = 9 − . Open boxes show the observed states with the definite spin-parity assignments[19,35], and other symbols show the calculated result. The filled boxes show the linear-chain bands, while lines show the non-cluster states which have the reduced widths lower than 0.10 MeV 1/2 .…”

Three-body model for the analysis of quasifree scattering reactions in inverse kinematics

“…However, because the method does not make use of the IA, it may be applicable to lower energies. Some knockout experiments on proton targets have, in fact, been performed at energies of the order of 70-80 MeV/nucleon [12,13,40,41] and, thus, the comparison with the present theory could provide an assessment of the validity of this model at these energies. In particular, our formalism can include on the same footing the contribution from the pure three-body breakup and the (p,d) channel, which might be important at these energies.…”

“…To conclude this section, it is noted that the DWIA amplitude (40) neglects FSIs between the incident and struck nucleons and, in particular, the (p,d) channel. This is in contrast to the formalism proposed here, in which these FSI effects are incorporated in the three-body final wave function.…”

Large acceptance spectrometers for invariant mass spectroscopy of exotic nuclei and future developments

“…Let us take an example of the recent experiment on the 1n knockout reaction 17 C+p at 70 MeV/u by Satou et al [3] at the RIPS facility [4] at RIKEN, where unbound states of 16 C were studied. In this case, decay particles 15 C and a neutron emitted in the forward kinematical cone were measured.…”