| Records |
| Author |
IDS Collaboration (Heideman, J. et al); Algora, A.; Morales, A.I. |
| Title |
Evidence of nonstatistical neutron emission following beta decay near doubly magic Sn-132 |
Type |
Journal Article |
| Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
108 |
Issue |
2 |
Pages |
024311 - 9pp |
| Keywords |
|
| Abstract |
Models of the beta-delayed neutron emission (beta n) assume that neutrons are emitted statistically via an intermediate compound nucleus post beta decay. Evidence to the contrary was found in an In-134 beta-decay experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in Sn-134 to known low-lying, single-particle states in Sn-133 were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in Sn-133 was studied using gamma-ray detectors. Individual beta n probabilities were determined by correlating the relative intensities and energies of neutrons and gamma rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in beta-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed. |
Address  |
[Heideman, J.; Grzywacz, R.; Xu, Z. Y.; Madurga, M.; Halverson, C.; King, T. T.; Singh, M.; Yokoyama, R.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9985 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:001053419100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5620 |
| Permanent link to this record |
| |
|
| |
| Author |
Ikeno, N.; Yamagata-Sekihara, J.; Nagahiro, H.; Jido, D.; Hirenzaki, S. |
| Title |
Formation of heavy-meson bound states by two-nucleon pick-up reactions |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
84 |
Issue |
5 |
Pages |
054609 - 7pp |
| Keywords |
|
| Abstract |
We develop a model to evaluate the formation rate of the heavy mesic nuclei in two-nucleon pick-up reactions and apply it to the (6)Li target cases for the formation of heavy meson-alpha bound states, as examples. The existence of the quasideuteron in the target nucleus is assumed in this model. It is found that mesic nuclei formation in recoilless kinematics is possible even for heavier mesons than the nucleon in two-nucleon pick-up reactions. We find the formation rate of the meson-alpha bound states can be around half of the elementary cross sections at the recoilless kinematics with small distortions. |
| Address |
[Ikeno, N; Nagahiro, H; Hirenzaki, S] Nara Womans Univ, Dept Phys, Nara 6308506, Japan |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0556-2813 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000296881200003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
798 |
| Permanent link to this record |
| |
|
| |
| Author |
Ikeno, N.; Ono, A.; Nara, Y.; Ohnishi, A. |
| Title |
Effects of Pauli blocking on pion production in central collisions of neutron-rich nuclei |
Type |
Journal Article |
| Year |
2020 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
101 |
Issue |
3 |
Pages |
034607 - 9pp |
| Keywords |
|
| Abstract |
Pauli blocking is carefully investigated for the processes of NN <-> N Delta and Delta -> N pi in heavy-ion collisions, aiming at a more precise prediction of the pi(-)/pi(+) ratio which is an important observable to constrain the high-density symmetry energy. We use the AMD + JAM approach, which combines the antisymmetrized molecular dynamics for the time evolution of nucleons and the Jet AA Microscopic transport model to treat processes for Delta resonances and pions. As is known in general transport-code simulations, it is difficult to treat Pauli blocking very precisely due to unphysical fluctuations and additional smearing of the phase-space distribution function, when Pauli blocking is treated in the standard method of JAM. We propose an improved method in AMD + JAM to use the Wigner function precisely calculated in AMD as the blocking probability. Different Pauli blocking methods are compared in heavy-ion collisions of neutron-rich nuclei, Sn-132+Sn-124, at 270 MeV/nucleon. With the more accurate method, we find that Pauli blocking is stronger, in particular for the neutron in the final state in NN -> N Delta and Delta -> N pi, compared to the case with a proton in the final state. Consequently, the pi(-)/pi(+) ratio becomes higher when the Pauli blocking is improved, the effect of which is found to be comparable to the sensitivity to the high-density symmetry energy. |
| Address |
[Ikeno, Natsumi] Tottori Univ, Dept Agr Life & Environm Sci, Tottori 6808551, Japan |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9985 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000519701800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4327 |
| Permanent link to this record |
| |
|
| |
| Author |
Ikeno, N.; Molina, R.; Oset, E. |
| Title |
Triangle singularity mechanism for the pp -> pi(+)d fusion reaction |
Type |
Journal Article |
| Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
104 |
Issue |
1 |
Pages |
014614 - 16pp |
| Keywords |
|
| Abstract |
We develop a model for the pp -> pi(+)d reaction based on the pp -> Delta(1232)N transition followed by Delta(1232) -> pi N' decay and posterior fusion of NN' to give the deuteron. We show that the triangle diagram depicting this process develops a triangle singularity leading to a large cross section of this reaction compared to ordinary fusion reactions. The results of the calculation also show that the process is largely dominated by the pp system in L = 2 and S = 0, which transfers J = 2 to the final pi(+)d system. This feature is shown to be well suited to provide L = 2, S = 1, and J(tot) = 3 for np in the np(I = 0) pi(-)pp reaction followed by the pp -> pi(+)d reaction, which has been proposed recently, as a means of describing the so far assumed dibaryon d* (2380) peak. |
| Address |
[Ikeno, Natsumi] Tottori Univ, Dept Agr Life & Environm Sci, Tottori 6808551, Japan, Email: ikeno@tottori-u.ac.jp; |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9985 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000677555100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4908 |
| Permanent link to this record |
| |
|
| |
| Author |
Ilner, A.; Blair, J.; Cabrera, D.; Markert, C.; Bratkovskaya, E. |
| Title |
Probing hot and dense nuclear matter with K*, (K)over-bar* vector mesons |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
99 |
Issue |
2 |
Pages |
024914 - 22pp |
| Keywords |
|
| Abstract |
We investigate the possibility of probing the hot and dense nuclear matter-created in relativistic heavyion collisions (HICs)-with strange vector mesons (K*, (K) over bar*). Our analysis is based on the nonequilibrium parton-hadron-string dynamics (PHSD) transport approach which incorporates partonic and hadronic degrees of freedom and describes the full dynamics of HIC on a microscopic level-starting from the primary nucleon-nucleon collisions to the formation of the strongly interacting quark gluon plasma (QGP), followed by dynamical hadronization of (anti)quarks as well as final hadronic elastic and inelastic interactions. This allows us to study the K* and (K) over bar* meson formation from the QGP as well as the in-medium effects related to the modification of their spectral properties during the propagation through the dense and hot hadronic environment in the expansion phase. We employ relativistic Breit-Wigner spectral functions for the K*, (K) over bar* mesons with self-energies obtained from a self-consistent coupled-channel G-matrix approach to study the role of in-medium effects on the K* and (K) over bar* meson dynamics in heavy-ion collisions from FAIR/NICA to LHC energies. According to our analysis most of the final K* /(K) over bar*'s, that can be observed experimentally by reconstruction of the invariant mass of pi + K((K) over bar) pairs, are produced during the late hadronic phase and originate dominantly from the K((K) over bar) + pi -> K*( (K) over bar*) formation channel. The amount of K*/ (K) over bar*'s, originating from the QGP channel is comparatively small even at LHC energies and those K* /(K) over bar*'s can hardly be reconstructed experimentally due to the rescattering of final pions and (anti)kaons. This mirrors the results from our previous study on the strange vector-meson production in heavy-ion collisions at RHIC energies. We demonstrate that K* /(K) over bar* in-medium effects should be visible at FAIR/NICA and BES RHIC energies, where the production of K* /(K) over bar*'s occurs at larger net-baryon densities. Finally, we present the experimental procedures to extract the information on the resonance masses and widths by fitting the final mass spectra at LHC energies. |
| Address |
[Ilner, Andrej; Bratkovskaya, Elena] Johann Wolfgang Goethe Univ Frankfurt Main, Inst Theoret Phys, D-60438 Frankfurt, Germany, Email: ilner@fias.uni-frankfurt.de |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9985 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000459905400005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3925 |
| Permanent link to this record |
