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Nuclear Experiment

New submissions

[ total of 7 entries: 1-7 ]
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New submissions for Mon, 25 Sep 17

[1]  arXiv:1709.07501 [pdf, ps, other]
Title: Reorientation-effect measurement of the first 2$^+$ state in $^{12}$C: confirmation of oblate deformation
Subjects: Nuclear Experiment (nucl-ex)

A Coulomb-excitation reorientation-effect measurement using the TIGRESS $\gamma-$ray spectrometer at the TRIUMF/ISAC II facility has permitted the first determination of the $\langle 2^+_1\mid\mid \hat{E2} \mid\mid 2^+_1\rangle$ diagonal matrix element in $^{12}$C from particle$-\gamma$ coincidence data. Required state-of-the-art no-core shell model calculations of the nuclear polarizability for the ground and first-excited (2$^+_1$) states in $^{12}$C using chiral NN N$^4$LO500 and NN+3NF350 interactions have been performed. Consistent predictions show a larger polarizability than previously anticipated. The polarizability of the 2$^+_1$ state is introduced into the current and previous Coulomb-excitation reorientation-effect analysis of $^{12}$C. Spectroscopic quadrupole moments of $Q_{_S}(2_1^+)= +0.053(44)$ eb and $Q_{_S}(2_1^+)= +0.08(3)$ eb are determined, respectively, yielding a weighted average of $Q_{_S}(2_1^+)= +0.071(25)$ eb, in agreement with recent ab initio calculations. The present measurement confirms that the 2$^+_1$ state of $^{12}$C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei.

Cross-lists for Mon, 25 Sep 17

[2]  arXiv:1709.07443 (cross-list from physics.ins-det) [pdf, ps, other]
Title: Defective fission correlation data from the 2E-2v method
Comments: 5 pages, 5 figures
Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

The double-energy double-velocity ($2E$-$2v$) method allows assessing fission-fragment mass yields prior to and after prompt neutron emission with high resolution. It is, therefore, considered as a complementary technique to assess average prompt neutron multiplicity as a function of fragment properties. We have studied the intrinsic features of the $2E$-$2v$ method by means of event-wise generated fission-fragment data and found severe short-comings in the method itself as well as in some common practice of application. We find that the $2E$-$2v$ method leads to large deviations in the correlation between the prompt neutron multiplicity and pre-neutron mass, which deforms and exaggerates the so called `sawtooth' shape of $\bar{\nu}(A)$. We have identified the treatment of prompt neutron emission from the fragments as the origin of the problem. The intrinsic nature of this deficiency, risk to render $2E$-$2v$ experiments much less interesting. We suggest a method to correct the $2E$-$2v$ data, and recommend applying this method to previous data acquired in $2E$-$2v$ experiments, as well.

[3]  arXiv:1709.07449 (cross-list from physics.ins-det) [pdf, other]
Title: The SPEDE spectrometer
Comments: 8 pages, 10 figures
Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

The electron spectrometer, SPEDE, has been developed and will be employed in conjunction with the Miniball spectrometer at the HIE-ISOLDE facility, CERN. SPEDE allows for direct measurement of internal conversion electrons emitted in-flight, without employing magnetic fields to transport or momentum filter the electrons. Together with the Miniball spectrometer, it enables simultaneous observation of {\gamma} rays and conversion electrons in Coulomb-excitation experiments using radioactive ion beams.

[4]  arXiv:1709.07846 (cross-list from physics.ins-det) [pdf, ps, other]
Title: $^{100}$Mo-enriched Li$_2$MoO$_4$ scintillating bolometers for $0ν 2β$ decay search: from LUMINEU to CUPID-0/Mo projects
Authors: D.V. Poda (for LUMINEU, EDELWEISS, and CUPID-0/Mo Collaborations)
Comments: Proceedings of the MEDEX'17 meeting (Prague, May 29 - June 2, 2017)
Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

A scintillating bolometer technology based on $^{100}$Mo-enriched lithium molybdate (Li$_2$$^{100}$MoO$_4$) crystals has been developed by LUMINEU to search for neutrinoless double-beta ($0\nu 2\beta$) decay of $^{100}$Mo. The results of several low temperature tests at underground environments have proved the reproducibility of high detector performance and crystal radiopurity: in particular $\sim$5--6~keV FWHM energy resolution and at least 9$\sigma$ rejection of $\alpha$'s in the vicinity of the $0\nu 2\beta$ decay of $^{100}$Mo (3034 keV) and below 10~$\mu$Bq/kg bulk activity of $^{228}$Th and $^{226}$Ra. A modest acquired exposure (0.1~kg$\times$yr) is a limiting factor of the LUMINEU experiment sensitivity to the $0\nu 2\beta$ decay half-life of $^{100}$Mo ($T_{1/2}$ $\geq$ 0.7$\times$10$^{23}$ yr at 90\% C.L.), however the two-neutrino $2\beta$ decay has been measured with the best up to-date accuracy, $T_{1/2}$ = $\left[6.92 \pm 0.06(\mathrm{stat.}) \pm 0.36(\mathrm{syst.})\right] \times 10^{18}$ yr. The applicability of the LUMINEU technology for a tonne-scale $0\nu 2\beta$ decay bolometric project CUPID is going to be demonstrated by the CUPID-0/Mo experiment with $\sim$5~kg of $^{100}$Mo embedded in forty 0.2~kg Li$_2$$^{100}$MoO$_4$ scintillating bolometers. A first phase of the experiment with twenty Li$_2$$^{100}$MoO$_4$ detectors is in preparation at the Modane underground laboratory (France) to start by the end of 2017.

Replacements for Mon, 25 Sep 17

[5]  arXiv:1607.00480 (replaced) [pdf, other]
Title: Towards laboratory detection of topological vortices in superfluid phases of QCD
Comments: 6 pages, 3 figures, published version
Journal-ref: Mod. Phys. Lett. A 32, 1750170 (2017)
Subjects: High Energy Physics - Phenomenology (hep-ph); Superconductivity (cond-mat.supr-con); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
[6]  arXiv:1701.03830 (replaced) [pdf, other]
Title: Revealing long-range multi-particle collectivity in small collision systems via subevent cumulants
Comments: 23 pages, 10 figures, replace with the published version
Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
[7]  arXiv:1706.05707 (replaced) [pdf, ps, other]
Title: Analytic parametrizations of the $γ^\ast N \to N(1440)$ form factors inspired by Light-Front holography
Authors: G. Ramalho
Comments: 7 pages, 4 figures. Extended version. Accepted for publication
Journal-ref: Phys. Rev. D 96, 054021 (2017)
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
[ total of 7 entries: 1-7 ]
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