Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in ^{78}Br. ...They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The
γ
-ray strength function (
γ
SF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows ...measurements of these properties across a wide range of previously inaccessible nuclei. Proton–
γ
coincidence events from the
d
(
86
Kr
,
p
γ
)
87
Kr
reaction were measured at iThemba LABS and the
γ
SF and NLD in
87
Kr
was obtained. The low-energy region of the
γ
SF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The
γ
SF and NLD are used as input parameters to Hauser–Feshbach calculations to constrain
(
n
,
γ
)
cross sections of nuclei using the TALYS reaction code. These results are compared to
86
Kr
(
n
,
γ
)
data from direct measurements.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The conditions for reaching degeneracy in chiral partner bands built on two-quasiparticle configurations are examined using the two-quasiparticle-plus-triaxial-rotor model. It is shown that in order ...for degeneracy to occur it is not sufficient to have an aplanar orientation of the total angular momentum, but the angular momenta of the two valence particles need to be completely aligned along the short and long nuclear axes. Such perfect alignment seems impossible to reach with realistic parameters within this model. These results suggest that two-quasiparticle chiral bands may be formed in suitable nuclei, but perfect degeneracy between the partner bands is unlikely to be found.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Nuclear chiral systems exhibit chiral symmetry bands, built on left-handed and right-handed angular momentum nucleon configurations. The experimental search for such chiral systems revealed a number ...of suitable candidates, however an unambiguous identification of nuclear chiral symmetry is still outstanding. In this work it is shown that the decay patterns of chiral bands built on multi-quasiparticle configurations are different from those involving different single-particle configurations. It is suggested to use the observed decay patterns of chiral candidates as a new model-independent test of chiral symmetry.
Gamma-ray line production cross sections from nuclear reactions induced by 30 - 200 MeV protons on natC and Mylar targets have been measured at the SSC facility of iThemba LABS. Results for the 4.439 ...and 6.129 MeV prominent lines of 12C and 16O of astrophysical concern are reported and discussed.
Two nearly degenerate positive-parity bands with the πg9/22⊗νg9/2−1 configuration and three nearly degenerate negative-parity bands with the πg9/2(p3/2,f5/2)⊗νg9/2−1 configuration have been ...identified in 81Kr. They are interpreted as chiral doublet bands and pseudospin-chiral triplet bands, which is supported by the constrained covariant density functional theory and the multiparticle plus rotor model calculations. The present work reports two new chiral configurations πg9/22⊗νg9/2−1 and πg9/2(p3/2,f5/2)⊗νg9/2−1, and the first example of pseudospin-chiral triplet bands involving the π(p3/2,f5/2) pseudospin doublet.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
.
The multi-particle-plus-triaxial-rotor (MPR) model calculations were performed for several nuclei in the 100, 130 and 190 mass regions. Multiple chiral systems associated with many-particle nucleon ...configurations were found, but they may not necessarily form pairs of near-degenerate bands in an obvious way. Excited chiral systems may exhibit better near-degeneracy than the yrast one. Projections of the angular momenta along the nuclear axes were examined to study the nature of the chiral bands.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is associated with a dismal prognosis. Here, we report an analysis of CNS relapse for patients treated within the UK NCRI ...phase III R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) 14 versus 21 randomised trial.
The R-CHOP 14 versus 21 trial compared R-CHOP administered two- versus three weekly in previously untreated patients aged ≥18 years with bulky stage I–IV DLBCL (n = 1080). Details of CNS prophylaxis were retrospectively collected from participating sites. The incidence and risk factors for CNS relapse including application of the CNS-IPI were evaluated.
177/984 patients (18.0%) received prophylaxis (intrathecal (IT) methotrexate (MTX)n = 163, intravenous (IV) MTXn = 2, prophylaxis type unknownn = 11 and IT MTX and cytarabinen = 1). At a median follow-up of 6.5 years, 21 cases of CNS relapse (isolatedn = 11, with systemic relapsen = 10) were observed, with a cumulative incidence of 1.9%. For patients selected to receive prophylaxis, the incidence was 2.8%. Relapses predominantly involved the brain parenchyma (81.0%) and isolated leptomeningeal involvement was rare (14.3%). Univariable analysis demonstrated the following risk factors for CNS relapse: performance status 2, elevated lactate dehydrogenase, IPI, >1 extranodal site of disease and presence of a ‘high-risk’ extranodal site. Due to the low number of events no factor remained significant in multivariate analysis. Application of the CNS-IPI revealed a high-risk group (4-6 risk factors) with a 2- and 5-year incidence of CNS relapse of 5.2% and 6.8%, respectively.
Despite very limited use of IV MTX as prophylaxis, the incidence of CNS relapse following R-CHOP was very low (1.9%) confirming the reduced incidence in the rituximab era. The CNS-IPI identified patients at highest risk for CNS recurrence.
ISCRTN number 16017947 (R-CHOP14v21); EudraCT number 2004-002197-34.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report γ-ray spectra for the line observed at Eγ = 4.44 MeV in our previous experiments at iThemba LABS’ SSC facility using 30 - 200 MeV proton beams to irradiate a natC target. It is actually a ...complex composed of several lines of interest broadened by Doppler effect. In addition to the dominant 4.439 MeV line of 12C, two other lines at Eγ = 4.319 and 4.445 MeV assigned to 11C and 11B, respectively, are significant components of this complex. The analysis of its line shapes based on nuclear reaction models is the main topic of this contribution.
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