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Nuclear Experiment

New submissions

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New submissions for Mon, 19 Feb 18

[1]  arXiv:1802.05907 [pdf, other]
Title: A Search for Possible Long Range Spin Dependent Interactions of the Neutron From Exotic Vector Boson Exchange
Comments: 10 pages, 3 figures
Subjects: Nuclear Experiment (nucl-ex); Instrumentation and Detectors (physics.ins-det)

We present a search for possible spin dependent interactions of the neutron with matter through exchange of spin 1 bosons with axial vector couplings as envisioned in possible extensions of the Standard Model. We sought this interaction using a slow neutron polarimeter that passed transversely polarized slow neutrons by unpolarized slabs of material arranged so that this interaction would tilt the plane of polarization and develop a component along the neutron momentum. The result for the rotation angle, $\phi'_{V_5} = [1.4\pm\,2.3(stat.)\pm\,2.8(sys.)]\times 10^{-5}~\mbox{rad}$ is consistent with zero. This result improves the upper bounds on the neutron-matter coupling $g_{A}^{2}$ from such an interaction by about 3 orders of magnitude for force ranges in the mm-$\mu$m regime.

Cross-lists for Mon, 19 Feb 18

[2]  arXiv:1802.05836 (cross-list from astro-ph.SR) [pdf, other]
Title: Impacts of nuclear-physics uncertainties in the s-process determined by Monte-Carlo variations
Comments: 6 pages, 4 figures, 2 tables, the Proceedings of "the 2017 Symposium on Nuclear Data"; a supplementary article of arXiv:1701.00489
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

The s-process, a production mechanism based on slow-neutron capture during stellar evolution, is the origin of about half the elements heavier than iron. Abundance predictions for s-process nucleosynthesis depend strongly on the relevant neutron-capture and $\beta$-decay rates, as well as on the details of the stellar model being considered. Here, we have used a Monte-Carlo approach to evaluate the nuclear uncertainty in s-process nucleosynthesis. We considered the helium burning of massive stars for the weak s-process and low-mass asymptotic-giant-branch stars for the main s-process. Our calculations include a realistic and general prescription for the temperature dependent uncertainty for the reaction cross sections. We find that the adopted uncertainty for (${\rm n},\gamma$) rates, tens of per cent on average, effects the production of s-process nuclei along the line of $\beta$-stability, and that the uncertainties in $\beta$-decay from excited state contributions, has the strongest impact on branching points.

[3]  arXiv:1802.05837 (cross-list from astro-ph.SR) [pdf, other]
Title: Sensitivity to neutron captures and beta-decays of the enhanced s-process in rotating massive stars at low metallicities
Comments: 3 pages, 3 figures, published in the Proceedings of "Nuclear Physics in Astrophysics Conference (NPA VII)"; see arXiv:1701.00489, for the completed results
Journal-ref: 2018 J. Phys.: Conf. Ser. 940 012051
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

The s-process in massive stars, producing nuclei up to $A\approx 90$, has a different behaviour at low metallicity if stellar rotation is significant. This enhanced s-process is distinct from the s-process in massive stars around solar metallicity, and details of the nucleosynthesis are poorly known. We investigated nuclear physics uncertainties in the enhanced s-process in metal-poor stars within a Monte-Carlo framework. We applied temperature-dependent uncertainties of reaction rates, distinguishing contributions from the ground state and from excited states. We found that the final abundance of several isotopes shows uncertainties larger than a factor of 2, mostly due to the neutron capture uncertainties. A few nuclei around branching points are affected by uncertainties in the $\beta$-decay.

Replacements for Mon, 19 Feb 18

[4]  arXiv:1711.09680 (replaced) [pdf, other]
Title: Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence
Authors: A1 Collaboration: D. Izraeli (1), T. Brecelj (2), P. Achenbach (3), A. Ashkenazi (1), R. Böhm (3), E. O. Cohen (1), M. O. Distler (3), A. Esser (3), R. Gilman (4), T. Kolar (2), I. Korover (1 and 5), J. Lichtenstadt (1), I. Mardor (1 and 6), H. Merkel (3), M. Mihovilovič (2 and 3), U. Müller (3), M. Olivenboim (1), E. Piasetzky (1), G. Ron (7), B. S. Schlimme (3), M. Schoth (3), C. Sfienti (3), S. Širca (8 and 2), S. Štajner (2), S. Strauch (9), M. Thiel (3), A. Weber (3), I. Yaron (1) ((1) School of Physics and Astronomy, Tel Aviv University, (2) Jožef Stefan Institute, (3) Institut für Kernphysik, Johannes Gutenberg-Universität, (4) Rutgers, The State University of New Jersey, (5) Department of Physics, (6) Soreq NRC, (7) Racah Institute of Physics, Hebrew University of Jerusalem, (8) Faculty of Mathematics and Physics, University of Ljubljana, (9) University of South Carolina)
Subjects: Nuclear Experiment (nucl-ex)
[5]  arXiv:1802.00693 (replaced) [pdf, other]
Title: A high-resolution study of levels in the astrophysically important nucleus $^{26}$Mg and resulting updated level assignments
Comments: 12 pages, 3 figures, 2 tables. Fixed missing reference and some index labelling in figures
Subjects: Nuclear Experiment (nucl-ex); Solar and Stellar Astrophysics (astro-ph.SR)
[ total of 5 entries: 1-5 ]
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