Erratum: Precision Mass Measurements on Neutron-Rich Rare-Earth Isotopes at JYFLTRAP: Reduced Neutron Pairing and Implications for r-Process Calculations [Phys. Rev. Lett. 120, 262701 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.120.262701.

Precision Mass Measurements on Neutron-Rich Rare-Earth Isotopes at JYFLTRAP: Reduced Neutron Pairing and Implications for r-Process Calculations

The rare-earth peak in the r-process abundance pattern depends sensitively on both the astrophysical conditions and subtle changes in nuclear structure in the region. This work takes an important step towards elucidating the nuclear structure and reducing the uncertainties in r-process calculations via precise atomic mass measurements at the JYFLTRAP double Penning trap. ^{158}Nd, ^{160}Pm, ^{162}Sm, and ^{164-166}Gd have been measured for the first time, and the precisions for ^{156}Nd, ^{158}Pm, ^{162,163}Eu, ^{163}Gd, and ^{164}Tb have been improved considerably. Nuclear structure has been probed via two-neutron separation energies S_{2n} and neutron pairing energy metrics D_{n}. The data do not support the existence of a subshell closure at N=100. Neutron pairing has been found to be weaker than predicted by theoretical mass models. The impact on the calculated r-process abundances has been studied. Substantial changes resulting in a smoother abundance distribution and a better agreement with the solar r-process abundances are observed.

Precision Mass Measurements of Neutron-Rich Neodymium and Samarium Isotopes and Their Role in Understanding Rare-Earth Peak Formation

The Canadian Penning Trap mass spectrometer at the Californium Rare Isotope Breeder Upgrade (CARIBU) facility was used to measure the masses of eight neutron-rich isotopes of Nd and Sm. These measurements are the first to push into the region of nuclear masses relevant to the formation of the rare-earth abundance peak at A∼165 by the rapid neutron-capture process. We compare our results with theoretical predictions obtained from "reverse engineering" the mass surface that best reproduces the observed solar abundances in this region through a Markov chain Monte Carlo technique. Our measured masses are consistent with the reverse-engineering predictions for a neutron star merger wind scenario.

Determining the rp-process flow through 56Ni: resonances in 57Cu(p,γ)58Zn identified with GRETINA

An approach is presented to experimentally constrain previously unreachable (p, γ) reaction rates on nuclei far from stability in the astrophysical rp process. Energies of all critical resonances in the (57)Cu(p,γ)(58)Zn reaction are deduced by populating states in (58)Zn with a (d, n) reaction in inverse kinematics at 75 MeV/u, and detecting γ-ray-recoil coincidences with the state-of-the-art γ-ray tracking array GRETINA and the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The results reduce the uncertainty in the (57)Cu(p,γ) reaction rate by several orders of magnitude. The effective lifetime of (56)Ni, an important waiting point in the rp process in x-ray bursts, can now be determined entirely from experimentally constrained reaction rates.

[Unusual presentation of rib malformation]

Rib malformation and anatomical variations are not well known and are still often underdiagnosed. Usually, rib malformations are fortuitously discovered. We describe here the case of a girl, 4 years and 4 months old, who presented at the emergency unit for fever and an anterior tumefaction of the ribcage, without any other symptoms. She was eupneic with a normal pulmonary auscultation and viral tonsillitis with a negative streptococcus test. The thoracic tumefaction was parasternal, painless, and fixed and measured approximately 2.5 × 2cm. Ultrasound findings consisted of a duplicated and hypoechogenic hypertrophy of the sterno-costal cartilage of the 4th left rib. Magnetic resonance imaging (MRI) confirmed the diagnosis of chondral bifidity of the sterno-costal junction of the 4th left rib. Fever, due to the viral tonsillitis, disappeared after 4 days. Rib malformations are rare, often anterior, unilateral, and preferentially located on the 3rd or the 4th rib. The main malformative rib lesions are bifid ribs, rib spurs, and widened ribs. Very rarely, they can be associated with Gorlin-Goltz syndrome or with other malformations such as VATER complex. The main differential diagnoses of these rib malformations are traumatic, tumoral, and infectious etiologies. In case of tumoral diseases, the topography of the lesion focuses the etiologic diagnosis: whereas an anterior and cartilaginous lesion is always benign, a lateral or posterior lesion can be an Ewing sarcoma. Rib malformation investigation consists in meticulous questioning, a complete clinical examination looking for any associated anomaly, completed by basic imaging explorations such as plain thoracic radiography focused on the ribcage and ultrasound. Finally, complementary computerized tomography or preferably MRI, depending on the anatomic location of the lesion, confirms the final diagnosis, as presented in our case report, and removes any uncertainty.

[Minoxidil intoxication, the pharmacological agent of a hair lotion]

Accidental intoxications in children are frequent but most of them are without serious consequences. We describe herein the case of a young girl who drank 100 mg of a topical hair lotion with minoxidil. On arrival, she had no symptoms except flush on the face and ears. Four and half hours after ingestion, tachycardia appeared with a pulse above 170 beats per min with hypotension at 76/24 mmHg. The heart rate remained between 170 and 190 beats per min for 12 h and then lowered to between 140 and 160 beats per min. Thirty-six hours after ingestion, the heart beat was at 140 beats per min. Minoxidil is a strong vasodilator used first in the 1970s for severe hypertension. It produces hypotension by direct arteriolar vasodilatation. Only a few cases of minoxidil intoxication have been described in the literature, including only one pediatric case. This young boy had only tachycardia of 160 beats per min for 40 h. Most serious cases have been described in adults. They suffered long-lasting tachycardia, hypotension, and ECG changes. Most patients need a bolus of normal saline fluid and some with hemodynamic problems need vasoactive drugs such as dopamine and/or phenylephrine. All patients need to be under medical supervision for a long time because of the product's very long action.

Doppler shift as a tool for studies of isobaric analog states of neutron-rich nuclei: application to 7He

We have developed a new technique to study exotic neutron-rich nuclei via their isobaric analog states (IAS). We populate high-isospin states in resonant reactions of radioactive ion beams with protons. Characteristic gamma rays emitted from excited decay products were used to identify the population of the IAS. We show that information on the differential and total cross section for formation of the IAS can be extracted from the energy spectrum of the Doppler-shifted gamma rays. This technique was applied to the study of T=3/2 states in 7Li, which are analogs of states in 7He. The analog of the 7He ground state was clearly observed, whereas the presence of the analog of a narrow 1/2(-) state at 0.6 MeV excitation in 7He reported by M. Meister et al. [Phys. Rev. Lett. 88, 102501 (2002)] was excluded at the 90% confidence level. Evidence is presented for a broad 1/2(-) state at a higher excitation energy in 7He.

Half-life of the doubly magic r-process nucleus 78Ni

Nuclei with magic numbers serve as important benchmarks in nuclear theory. In addition, neutron-rich nuclei play an important role in the astrophysical rapid neutron-capture process (r process). 78Ni is the only doubly magic nucleus that is also an important waiting point in the r process, and serves as a major bottleneck in the synthesis of heavier elements. The half-life of 78Ni has been experimentally deduced for the first time at the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory at Michigan State University, and was found to be 110(+100)(-60) ms. In the same experiment, a first half-life was deduced for 77Ni of 128(+27)(-33) ms, and more precise half-lives were deduced for 75Ni and 76Ni of 344(+20)(-24) ms and 238(+15)(-18) ms, respectively.

Analog states of 7He observed via the 6He(p,n) reaction

Isobaric analog states of 7He have been investigated by a novel technique involving the observation of the resonant yield of neutrons from the 6He(p,n) reaction in coincidence with gamma rays from the decay of the (0(+),T=1) state in 6Li. The gamma rays provide a clean signature for the isospin-conserving neutron decay of the low-lying isobaric analog resonances. It is conclusively shown that the analog of the recently observed low-lying spin-orbit partner of the 7He ground state does not exist. Evidence is presented that this state lies at much higher energies, in agreement with microscopic calculations.

End point of the rp process on accreting neutron stars

We calculate the rapid proton ( rp) capture process of hydrogen burning on the surface of an accreting neutron star with an updated reaction network that extends up to Xe, far beyond previous work. In both steady-state nuclear burning appropriate for rapidly accreting neutron stars (such as the magnetic polar caps of accreting x-ray pulsars) and unstable burning of type I x-ray bursts, we find that the rp process ends in a closed SnSbTe cycle. This prevents the synthesis of elements heavier than Te and has important consequences for x-ray burst profiles, the composition of accreting neutron stars, and potentially galactic nucleosynthesis of light p nuclei.

Half-life measurement for the rp-process waiting point nuclide 80Zr

X-ray bursts have been suggested as a possible site for the astrophysical rp-process. The time scale for the process is governed by beta-decay half-lives of several even-even N = Z waiting point nuclei, in particular, N = Z = 40 80Zr. A 4.1(+0.8/-0.6)-s beta(+)/EC half-life for 80Zr was determined by observing delayed 84-keV gamma rays depopulating a T(1/2) = 4-&mgr;s isomer at 312 keV in the daughter 80Y. As this half-life is lower than many previously predicted values, the calculated excessive production of A = 80 nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides.

Lifetime Measurements in (178)Hf

Lifetimes of levels from K(π) = 2(+), K(π) = 4(+) and several K(π) = 0(+) bands have been measured in the (178)Hf nucleus using the GRID technique. Lifetimes of the 2(+) and 3(+) levels were measured within the K(π) = 2(+) γ band. A lower limit was established for the lifetime of the 4(+) level of the K(π) = 4(+) band. The resulting upper limits for the absolute B(E2) values exclude collective transitions from the K(π) = 4(+) to the ground state band but not to the K(π)= 2(+) band. Level lifetimes were also measured for several states within three separate K(π)= 0(+) bands. Evidence is presented for a previously unobserved case of two excited K(π)= 0(+) bands being connected via collective E2 transitions.

Low-Spin States From Decay Studies in the Mass 80 Region

Neutron-deficient nuclei in the mass 80 region are known to exhibit strongly deformed ground states deduced mainly from yrast-state properties measured in-beam via heavy-ion fusion-evaporation reactions. Vibrational excitations and non-yrast states as well as their interplay with the observed rotational collectivity have been less studied to date within this mass region. Thus, several β-decay experiments have been performed to populate low-spin states in the neutron-deficient (80,84)Y and (80,84)Sr nuclei. An overview of excited 0(+) states in Sr and Kr nuclei is given and conclusions about shape evolution at low-spins are presented. In general, the non-yrast states in even-even Sr nuclei show mainly vibration-like collectivity which evolves to rotational behavior with increasing spin and decreasing neutron number.