Records |
Author |
Siciliano, M. et al; Gadea, A. |
Title |
Shape coexistence in neutron-deficient Hg-188 investigated via lifetime measurements |
Type |
Journal Article |
Year |
2020 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
Volume |
102 |
Issue |
1 |
Pages |
014318 - 16pp |
Keywords |
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Abstract |
Background: Shape coexistence in the Z approximate to 82 region has been established in mercury, lead, and polonium isotopes. For even-even mercury isotopes with 100 <= N <= 106 multiple fingerprints of this phenomenon are observed, which seems to be no longer present for N >= 110. According to a number of theoretical calculations, shape coexistence is predicted in the Hg-188 isotope. Purpose: The aim of this work was to measure lifetimes of excited states in Hg-188 to infer their collective properties, such as the deformation. Extending the investigation to higher-spin states, which are expected to be less affected by band-mixing effects, can provide additional information on the coexisting structures. Methods: The Hg-188 nucleus was populated using two different fusion-evaporation reactions with two targets, Gd-158 and Gd-160, and a beam of S-34 provided by the Tandem-ALPI accelerator complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the gamma rays were detected using the GALILEO gamma-ray spectrometer. Lifetimes of excited states were determined using the recoil-distance Doppler-shift method, employing the dedicated GALILEO plunger device. Results: Lifetimes of the states up to spin 16 (h) over bar were measured and the corresponding reduced transition probabilities were calculated. Assuming two-band mixing and adopting, as done commonly, the rotational model, the mixing strengths and the deformation parameters of the unperturbed structures were obtained from the experimental results. In order to shed light on the nature of the observed configurations in the Hg-188 nucleus, the extracted transition strengths were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach, limited to axial shapes, and the five-dimensional collective Hamiltonian, including the triaxial degree of freedom. Conclusions: The first lifetime measurement for states with spin >= 6 suggested the presence of an almost spherical structure above the 12(1)(+) isomer and allowed elucidating the structure of the intruder band. The comparison of the extracted B(E2) strengths with the two-band mixing model allowed the determination of the ground-state band deformation. Both beyond-mean-field calculations predict coexistence of a weakly deformed band with a strongly prolate-deformed one, characterized by elongation parameters similar to those obtained experimentally, but the calculated relative position of the bands and their mixing strongly differ. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Siciliano, M.; Zanon, I; Cicerchia, M.; de Angelis, G.; Galtarossa, F.; Gozzelino, A.; Hadynska-Klek, K.; Jaworski, G.; Napoli, D. R.; Valiente-Dobon, J. J.] INFN, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: marco.siciliano@lnl.infn.it |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000551404600001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4471 |
Permanent link to this record |
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Author |
AGATA Collaboration (Siciliano, M. et al); Gadea, A.; Perez-Vidal, R.M.; Domingo-Pardo, C. |
Title |
Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in Sn-106,Sn-108 |
Type |
Journal Article |
Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
Volume |
806 |
Issue |
|
Pages |
135474 - 7pp |
Keywords |
Lifetime; Nuclear structure; Multi-nucleon transfer; Light Sn; Tracking array |
Abstract |
The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted gamma rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the B(E2; 2(1)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B(E2;(+)(4) -> 2(1)(+)) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in Sn-108. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Siciliano, M.; Valiente-Dobon, J. J.; Goasduff, A.; Jaworski, G.; Marchi, T.; Napoli, D. R.; Saygi, B.; Egea-Canet, F. J.] Ist Nazl Fis Nucl, Lab Nazl Legnaro, Legnaro, PD, Italy, Email: marco.siciliano@lnl.infn.it |
Corporate Author |
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Thesis |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000571760900006 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4539 |
Permanent link to this record |
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Author |
Shi, P.P.; Baru, V.; Guo, F.K.; Hanhart, C.; Nefediev, A. |
Title |
Production of the X(4014) as the Spin-2 Partner of X(3872) in e + e – Collisions |
Type |
Journal Article |
Year |
2024 |
Publication |
Chinese Physics Letters |
Abbreviated Journal |
Chin. Phys. Lett. |
Volume |
41 |
Issue |
3 |
Pages |
031301 - 7pp |
Keywords |
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Abstract |
In 2021, the Belle collaboration reported the first observation of a new structure in the psi(2S)gamma final state produced in the two-photon fusion process. In the hadronic molecule picture, this new structure can be associated with the shallow isoscalar D*D* bound state and as such is an excellent candidate for the spin-2 partner of the X(3872) with the quantum numbers J(PC) = 2(++) conventionally named X-2. In this work we evaluate the electronic width of this new state and argue that its nature is sensitive to its total width, the experimental measurement currently available being unable to distinguish between different options. Our estimates demonstrate that the planned Super tau-Charm Facility offers a promising opportunity to search for and study this new state in the invariant mass distributions for the final states J/psi gamma and psi(2S)gamma. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Shi, Pan-Pan; Guo, Feng-Kun] Chinese Acad Sci, CAS Key Lab Theoret Phys, Inst Theoret Phys, Beijing 100190, Peoples R China, Email: panpan@ific.uv.es; |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0256-307x |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001189846900001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6051 |
Permanent link to this record |
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Author |
Servant, G.; Simakachorn, P. |
Title |
Ultrahigh frequency primordial gravitational waves beyond the kHz: The case of cosmic strings |
Type |
Journal Article |
Year |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
109 |
Issue |
10 |
Pages |
103538 - 24pp |
Keywords |
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Abstract |
We investigate gravitational -wave backgrounds (GWBs) of primordial origin that would manifest only at ultrahigh frequencies, from kilohertz to 100 gigahertz, and leave no signal at LIGO, the Einstein Telescope, the Cosmic Explorer, LISA, or pulsar -timing arrays. We focus on GWBs produced by cosmic strings and make predictions for the GW spectra scanning over high-energy scale (beyond 10 10 GeV) particle physics parameters. Signals from local string networks can easily be as large as the big bang nucleosynthesis/ cosmic microwave background bounds, with a characteristic strain as high as 10 – 26 in the 10 kHz band, offering prospects to probe grand unification physics in the 10 14 -10 17 GeV energy range. In comparison, GWB from axionic strings is suppressed (with maximal characteristic strain similar to 10 – 31 ) due to the early matter era induced by the associated heavy axions. We estimate the needed reach of hypothetical futuristic GW detectors to probe such GWB and, therefore, the corresponding high-energy physics processes. Beyond the information of the symmetry -breaking scale, the high -frequency spectrum encodes the microscopic structure of the strings through the position of the UV cutoffs associated with cusps and kinks, as well as potential information about friction forces on the string. The IR slope, on the other hand, reflects the physics responsible for the decay of the string network. We discuss possible strategies for reconstructing the scalar potential, particularly the scalar self -coupling, from the measurement of the UV cutoff of the GW spectrum. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Servant, Geraldine] Deutsch Elektronen Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany, Email: peera.simakachorn@ific.uv.es; |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001238459100006 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6150 |
Permanent link to this record |
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Author |
Servant, G.; Simakachorn, P. |
Title |
Constraining postinflationary axions with pulsar timing arrays |
Type |
Journal Article |
Year |
2023 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
108 |
Issue |
12 |
Pages |
123516 - 16pp |
Keywords |
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Abstract |
Models that produce axionlike particles (ALPs) after cosmological inflation due to spontaneous U(1) symmetry breaking also produce cosmic-string networks. Those axionic strings lose energy through gravitational-wave emission during the whole cosmological history, generating a stochastic background of gravitational waves that spans many decades in frequency. We can therefore constrain the axion decay constant and axion mass from limits on the gravitational-wave spectrum and compatibility with dark matter abundance as well as dark radiation. We derive such limits from analyzing the most recent NANOGrav data from pulsar timing arrays (PTAs). The limits are similar to the Neff bounds on dark radiation for ALP masses ma less than or similar to 10-22 eV. On the other hand, for heavy ALPs with ma greater than or similar to 0.1 GeV and NDW not equal 1, new regions of parameter space can be probed by PTA data due to the dominant domain-wall contribution to the gravitational-wave background. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
[Servant, Geraldine] DESY, Notkestr 85, D-22607 Hamburg, Germany, Email: geraldine.servant@desy.de; |
Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001155748800012 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
5933 |
Permanent link to this record |