Ⅰ. HIGHLIGHTS OF THE YEARRIKEN Accel. Prog. Rep. 53

Inclusive cross sections for one- and multi-nucleon removal from Sn, Sb,and Te projectiles beyond the N = 82 shell closure†
V. Vaquero,∗1 A. Jungclaus,∗1 J. L. Rodríguez-Sánchez,∗2 J. A. Tostevin,∗3 P. Doornenbal,∗4 K. Wimmer,∗5,∗4
S. Chen,∗4,∗6 E. Nácher,∗1 E. Sahin,∗7 Y. Shiga,∗8 D. Steppenbeck,∗4 R. Taniuchi,∗4,∗5 Z. Y. Xu,∗9 T. Ando,∗5H. Baba,∗4 F. L. Bello Garrote,∗7 S. Franchoo,∗10 A. Gargano,∗11 K. Hadynska-Klek,∗7 A. Kusoglu,∗12,∗13 J. Liu,∗9T. Lokotko,∗9 S. Momiyama,∗5 T. Motobayashi,∗4 S. Nagamine,∗5 N. Nakatsuka,∗14 M. Niikura,∗5 R. Orlandi,∗15T. Saito,∗5 H. Sakurai,∗4,∗5 P. A. Söderström,∗4 G. M. Tveten,∗7 Zs. Vajta,∗16 and M. Yalcinkaya∗1,∗12
Inclusive one- and multi-nucleon removal cross sections have been measured for several Sn, Sb and Te isotopes just beyond the N = 82 neutron shell closure.
The beams were produced in the projectile ﬁssion of a238
U beam at the Radioactive Isotope Beam Factory atRIKEN. The experimental cross sections were compared
to predictions from two diﬀerent versions of the Liege intranuclear cascade (INCL) model1,2) as shown in Fig. 1.
This ﬁgure shows an overall good agreement between
the calculations and the experimental results. In particular for the 0pxn removal from the N = 83 projectiles
133
Sn, 134 Sb, and 135 Te as well as the stable 112 Sn3) boththe magnitude and the gentle odd-even staggering of thecross sections is nicely reproduced by both calculations.
In contrast, none of them correctly describes the measured cross sections for one- and two-neutron removalfrom the N = 84 isotones 134 Sn and 135 Sb. This failure of the INCL model could be traced to the peculiar
structure of these nuclei with only a few valence neutrons
above the N = 82 shell gap.4)
Turning now to the one-proton knockout cross sections, Fig. 1(b) clearly shows that both calculations failto reproduce the experimental values for all three studied N = 84 projectiles, i.e. 134 Sn, 135 Sb and 136 Te. Note,however, that in this case the reﬁnements, which havebeen introduced in the modiﬁed version of the INCLcode, have a much stronger eﬀect as compared to thecase of one-neutron knockout, reducing the calculated
one-proton knockout cross sections by roughly a factorof two. The underlying reasons for the overestimation of
the cross section for the removal of the stronger boundnucleon species by the INCL model, which had alreadybeen recognized in the past, are still awaiting explana-Fig. 1. Comparison between experimental inclusive removal
cross sections and the results of calculations performed
with two diﬀerent versions (standard1) as dashed blueand modiﬁed2) as solid black lines) of the INCL codefor a) the 0pxn and b) the 1pxn removal channels. The
experimental cross sections for 0pxn removal from 112 Sn
shown in a) are taken from Ref. 3).

tion. The present data for multi-nucleon removal indicate that an ad-hoc increase of the excitation energy
in the INCL model at the end of the cascade process,an approach which has been suggested to cure the incapacity of the model to correctly describe the removalof deeply bound nucleons, does not address the origin of
this problem.
Finally, we mention that the experimental inclusive
cross section for one-proton removal from semi-magic134
Sn was also compared with calculations based oneikonal direct reaction theory with structure information from the nuclear shell model and refer to the original publication for further details.

Condensed from the article in Phys. Lett. B 795, 356 (2019)
IEM-CSIC Madrid∗2 Universidad de Santiago de Compostela∗3 University of Surrey∗4 RIKEN Nishina Center∗5 Department of Physics, University of Tokyo∗6 Peking University, Bejing∗7 University of Oslo, Oslo∗8 Department of Physics, Rikkyo University∗9 University of Hong Kong
∗10 IN2P3-CNRS, Orsay∗11 INFN, Napoli∗12 Istanbul University∗13 ELI-NP, Magurele∗14 Department of Physics, Kyoto University∗15 Advanced Science Research Center, JAEA
∗16 MTA Atomki†∗1References

1) D. Mancusi et al., Phys. Rev. C 90, 054602 (2014).
2) J. L. Rodríguez-Sánchez et al., Phys. Rev. C 96, 054602(2017).
3) L. Audirac et al., Phys. Rev. C 36, 041602(R) (2013).
4) V. Vaquero et al., Phys. Rev. Lett. 118, 202502 (2017).

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