200 research outputs found
Breakdown of the Z=8 shell closure in unbound 12O and its mirror symmetry
An excited state in the proton-rich unbound nucleus 12O was identified at 1.8(4) MeV via missing-mass spectroscopy with the 14O(p,t) reaction at 51 AMeV. The spin-parity of the state was determined to be 0+ or 2+ by comparing the measured differential cross sections with distorted-wave calculations. The lowered location of the excited state in 12O indicates the breakdown of the major shell closure at Z=8 near the proton drip line. This demonstrates the persistence of mirror symmetry in the disappearance of the magic number 8 between 12O and its mirror partner 12Be
High-precision measurement of the half-life of Ga
The beta-decay half-life of 62Ga has been studied with high precision using
on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to
0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} =
116.19(4) ms. This result is more precise than any previous measurement by
about a factor of four or more. The present value is in agreement with older
literature values, but slightly disagrees with a recent measurement. We
determine an error weighted average value of all experimental half-lives of
116.18(4) ms.Comment: 9 pages, 5 figures, accepted for publication in PR
Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains
The proton-unbound argon and chlorine isotopes have been studied by measuring trajectories
of their decay-in-flight products by using a tracking technique with micro-strip detectors. The
proton (1p) and two-proton (2p) emission processes have been detected in the measured angular
correlations “heavy-fragment”+p and “heavy-fragment”+p+p, respectively. The ground states of
the previously unknown isotopes 30Cl and 28Cl have been observed for the first time, providing the
1p separation energies Sp of −0.48(2) and −1.60(8) MeV, respectively. The relevant systematics of
1p and 2p separation energies have been studied theoretically in the core+p and core+p+p cluster
models. The first-time observed excited states of 31Ar allow to infer the 2p-separation energy S2p
of 6(34) keV for its ground state. The first-time observed state in 29Ar with S2p = −5.50(18) MeV
can be identified either as a ground or an excited state according to different systematics.Helmholtz Association grant IK-RU-002Helmholtz International Center for FAIR HIC for FAIRRussian Science Foundation grant No. 17-12-01367Polish National Science Center Contract No. UMO- 2015/17/B/ST2/00581Polish Ministry of Science and Higher Education Grant No. 0079/DIA/2014/43, Grant DiamentowyHelmholtz- CAS Joint Research Group grant HCJRG-10
Deep excursion beyond the proton dripline. II. Toward the limits of existence of nuclear structure
Prospects of experimental studies of argon and chlorine isotopes located far beyond the proton dripline are studied by using systematics and cluster models. The deviations from the widespread systematics observed in
28
,
29
Cl
and
29
,
30
Ar
have been theoretically substantiated, and analogous deviations have been predicted for the lighter chlorine and argon isotopes. The limits of nuclear structure existence are predicted for Ar and Cl isotopic chains, with
26
Ar
and
25
Cl
found to be the lightest sufficiently long-living nuclear systems. By simultaneous measurements of protons and
γ
rays following decays of such systems as well as their
β
-delayed emission, an interesting synergy effect may be achieved, which is demonstrated by the example of
30
Cl
and
31
Ar
ground-state studies. Such a synergy effect may be provided by the new EXPERT setup (EXotic Particle Emission and Radioactivity by Tracking) being operated inside the fragment separator and spectrometer facility at GSI, Darmstadt.Helmholtz Association de Alemania. IK-RU-002Russian Science Foundation. 17-12-01367Polish National Science Center. UMO2015/17/B/ST2/00581Polish Ministry of Science and Higher Education. 0079/DIA/2014/43Helmholtz- CAS Joint Research Group de Alemania. HCJRG-108Ministerio de Educación y Ciencia, España. FPA2016-77689-C2-1-RMinistry of Education, Youth and Sports de la República Checa. LTT17003 y LM201504
Spectroscopy of excited states of unbound nuclei 30 Ar and 29 Cl
Several states of proton-unbound isotopes
30
Ar
and
29
Cl
were investigated by measuring their in-flight decay products,
28
S
+ proton + proton and
28
S
+ proton, respectively. A refined analysis of
28
S
-proton angular correlations indicates that the ground state of
30
Ar
is located at
2
.
45
+
0.05
−
0.10
MeV above the two-proton emission threshold. The investigation of the decay mechanism of the
30
Ar
ground state demonstrates that it has the transition dynamics. In the “transitional” region, the correlation patterns of the decay products present a surprisingly strong sensitivity to the two-proton decay energy of the
30
Ar
ground state and the one-proton decay energy as well as the one-proton decay width of the
29
Cl
ground state. The comparison of the experimental
28
S
-proton angular correlations with those resulting from Monte Carlo simulations of the detector response illustrates that other observed
30
Ar
excited states decay by sequential emission of protons via intermediate resonances in
29
Cl
. Based on the findings, the decay schemes of the observed states in
30
Ar
and
29
Cl
were constructed. For calibration purposes and for checking the performance of the experimental setup, decays of the previously known states of a two-proton emitter
19
Mg
were remeasured. Evidences for one new excited state in
19
Mg
and two unknown states in
18
Na
were found.Helmholtz International Center for FAIR de Alemania (HIC for FAIR) IK-RU-002Russian Ministry of Education and Science. NSh-932.2014.2Russian Science Foundation. 17-12-01367Polish National Science Center. UMO-2011/01/B/ST2/01943Polish Ministry of Science and Higher Education. 0079/DIA/2014/43HelmholtzCAS Joint Research Group de Alemania. HCJRG-108Ministerio de Ciencia, Innovación y Universidades de España (MICINN). FPA2009-0884
Blimp1(+) cells generate functional mouse sebaceous gland organoids in vitro
Most studies on the skin focus primarily on the hair follicle and interfollicular epidermis, whereas little is known regarding the homeostasis of the sebaceous gland (SG). The SG has been proposed to be replenished by different pools of hair follicle stem cells and cells that resides in the SG base, marked by Blimp1. Here, we demonstrate that single Blimp1(+) cells isolated from mice have the potential to generate SG organoids in vitro. Mimicking SG homeostasis, the outer layer of these organoids is composed of proliferating cells that migrate inward, undergo terminal differentiation and generating lipid-filled sebocytes. Performing confocal microscopy and mass-spectrometry, we report that these organoids exhibit known markers and a lipidomic profile similar to SGs in vivo. Furthermore, we identify a role for c-Myc in sebocyte proliferation and differentiation, and determine that SG organoids can serve as a platform for studying initial stages of acne vulgaris, making this a useful platform to identify potential therapeutic targets
Search for {\eta}'(958)-nucleus bound states by (p,d) reaction at GSI and FAIR
The mass of the {\eta}' meson is theoretically expected to be reduced at
finite density, which indicates the existence of {\eta}'-nucleus bound states.
To investigate these states, we perform missing-mass spectroscopy for the (p,
d) reaction near the {\eta}' production threshold. The overview of the
experimental situation is given and the current status is discussed.Comment: 6 pages, 3 figures; talk at II Symposium on applied nuclear physics
and innovative technologies, September 24th - 27th, 2014, Jagiellonian
University, Krak\'ow Poland; to appear in Acta Physica Polonica
Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT
This paper describes digital radio astronomical receivers used for decameter
and meter wavelength observations. This paper describes digital radio
astronomical receivers used for decameter and meter wavelength observations.
Since 1998, digital receivers performing on-the-fly dynamic spectrum
calculations or waveform data recording without data loss have been used at the
UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio
telescope. Here we detail these receivers developed for operation in the strong
interference environment that prevails in the decameter wavelength range. Data
collected with these receivers allowed us to discover numerous radio
astronomical objects and phenomena at low frequencies, a summary of which is
also presented.Comment: 24 pages, 15 figure
Spectroscopy of -nucleus bound states at GSI and FAIR --- very preliminary results and future prospects ---
The possible existence of \eta'-nucleus bound states has been put forward
through theoretical and experimental studies. It is strongly related to the
\eta' mass at finite density, which is expected to be reduced because of the
interplay between the anomaly and partial restoration of chiral
symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as
an overview of the experimental program at GSI and future plans at FAIR are
discussed.Comment: 7 pages, 3 figures; talk at the International Conference on Exotic
Atoms and Related Topics (EXA2014), Vienna, Austria, 15-19 September 2014. in
Hyperfine Interactions (2015
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