The FINUDA experiment collected data to study the production of hypernuclei on different nuclear targets. The hypernucleus formation occurred through the strangeness-exchange reaction $K^-_{stop} + ; ^AZ rightarrow ; ^A_{Lambda}Z + pi^-$. From the analysis of the momentum of the emerging $pi^-$, binding energies and formation probabilities of $^7_{Lambda}$Li, $^9_{Lambda}$Be, $^{13}_{Lambda}$C and $^{16}_{Lambda}$O have been measured and are here presented. The behavior of the formation probability as a function of the atomic mass number A is also discussed.
An experimental study of the $K^-_{stop}Arightarrow Sigma^- p A$ reaction on $A=^6$Li, $^7$Li, $^9$Be, $^{13}$C and $^{16}$O $p$-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DA$Phi$NE $phi$-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a $(np)$ pair embedded in the $A$ nucleus can be obtained from the study of the missing mass distributions.
The E885 collaboration utilized the 1.8 GeV/c K^- beam line at the AGS to accumulate 3 x 10^5 (K^-,K^+) events. Xi hypernuclear states are expected to be produced through the reaction K^- + ^{12}C -> K^+ + ^{12}_{Xi}Be. The measured missing-mass spectrum indicates the existence of a signal below the threshold for free Xi production. Although the resolution was not sufficient to resolve discrete hypernuclear states, the excess of events in the region of missing mass, kinematically inaccessible in free Xi production, is compared to theoretical prediction for ^{12}_{Xi}Be production.
The ${}^{12}mathrm{C}(alpha,gamma){}^{16}mathrm{O}$ reaction plays a key role in the evolution of stars with masses of $M >$ 0.55 $M_odot$. The cross-section of the ${}^{12}mathrm{C}(alpha,gamma){}^{16}mathrm{O}$ reaction within the Gamow window ($E_textrm{c.m.}$ = 300 keV, $T_textrm9$ = 0.2) is extremely small (about $10^{-17}$ barn), which makes the direct measurement in a ground-based laboratory with existing techniques unfeasible. Up until now, the cross-sections at lower energies can only be extrapolated from the data at higher energies. However, two subthreshold resonances, located at $E_x$ = 7.117 MeV and $E_x$ = 6.917 MeV, make this extrapolation more complicated. In this work, the 6.917 MeV subthreshold resonance in the ${}^{12}mathrm{C}(alpha,gamma){}^{16}mathrm{O}$ reaction was investigated via the ${}^{12}mathrm{C}({}^{11}mathrm{B},{}^{7}mathrm{Li}){}^{16}mathrm{O}$ reaction. The experiment was performed using the Q3D magnetic spectrograph at the HI-13 tandem accelerator. We measured the angular distribution of the ${}^{12}mathrm{C}({}^{11}mathrm{B},{}^{7}mathrm{Li}){}^{16}mathrm{O}$ transfer reaction leading to the 6.917 MeV state. Based on the FRDWBA analysis, we derived the asymptotic normalization coefficient (ANC) of the 6.917 MeV level in $^{16}$O to be (1.10 $pm$ 0.29) $times 10^{10}$ fm$^{-1}$, with which the reduced $alpha$ width was computed to be $18.0pm4.7$ keV at the channel radius of 6.5 fm. Finally, we calculated the astrophysical $S_{E2}(300)$ factor of the ground-state transitions to be 46.2 $pm$ 7.7 keV b. The result for the astrophysical $S_{E2}(300)$ factor confirms the values obtained in various direct and indirect measurements and presents an independent examination of the most important data in nuclear astrophysics.
The dissociation features in nuclear track emulsion of $^9$Be, $^{9,10}$C, and $^{12}$N nuclei of 1.2 A GeV energy are presented. The data presented for the nucleus $^9$Be can be considered as evidence that there is a core in its structure in the form of 0$^+$ and 2$^+$ states of the $^8$Be nucleus having roughly equal weights. Events of coherent dissociation $^9$C$rightarrow 3^3$He associated with the rearrangement of the nucleons outside the $alpha$-clustering are identified. A pattern of the charge fragment topology in the dissociation of $^{10}$C and $^{12}$N nuclei is obtained for the first time. Contribution of the unbound nucleus decays to the cascade process $^{10}$C$rightarrow ^9$B$rightarrow ^8$Be is identified.
As suggested in a Comment by Peters, Phys. Rev. C {bf 96}, 029801 (2017), a correction is applied to the $^{13}$C($alpha$,n)$^{16}$O data of Harissopulos {it et al.}, Phys. Rev. C {bf 72}, 062801(R) (2005). The correction refers to the energy-dependent efficiency of the neutron detector and appears only above the ($alpha$,n$_1$) threshold of the $^{13}$C($alpha$,n)$^{16}$O reaction at about $E_alpha approx 5$ MeV. The corrected data are lower than the original data by almost a factor of two. The correction method is verified using recent neutron spectroscopy data and data from the reverse $^{16}$O(n,$alpha$)$^{13}$C reaction.