| 1. |
- Bacca, S., et al.
(author)
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Neutrino processes in partially degenerate neutron matter
- 2012
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In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 758:1, s. 34-
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Journal article (peer-reviewed)abstract
- We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.
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| 2. |
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| 3. |
- Hagen, G., et al.
(author)
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Neutron and weak-charge distributions of the Ca-48 nucleus
- 2016
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In: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2481 .- 1745-2473. ; 12:2, s. 186-190
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Journal article (peer-reviewed)abstract
- What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. Although the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus Ca-48. We show that the neutron skin (difference between the radii of the neutron and proton distributions) is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities that are at present targeted by precision measurements. Based on ab initio results for Ca-48, we provide a constraint on the size of a neutron star.
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| 4. |
- Hernandez, O. J., et al.
(author)
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A Statistical Analysis of the Nuclear Structure Uncertainties in μD
- 2020
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In: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 833-837
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Conference paper (peer-reviewed)abstract
- The charge radius of the deuteron (D), was recently determined to three times the precision compared with previous measurements using the measured Lamb shift in muonic deuterium ((formula presented)D). However, the (formula presented)D value is 5.6 (formula presented) smaller than the world averaged CODATA-2014 value (Pohl R et al. (2016) Science 353:669 [1]). To shed light on this discrepancy we analyze the uncertainties of the nuclear structure calculations of the Lamb shift in (formula presented)D and conclude that nuclear theory uncertainty is not likely to be the source of the discrepancy.
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| 5. |
- Hernandez, O. J., et al.
(author)
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The deuteron-radius puzzle is alive: A new analysis of nuclear structure uncertainties
- 2018
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 778, s. 377-383
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Journal article (peer-reviewed)abstract
- To shed light on the deuteron radius puzzle we analyze the theoretical uncertainties of the nuclear structure corrections to the Lamb shift in muonic deuterium. We find that the discrepancy between the calculated two-photon exchange correction and the corresponding experimentally inferred value by Pohl etal. [1] remain. The present result is consistent with our previous estimate, although the discrepancy is reduced from 2.6 sigma about 2 sigma. The error analysis includes statistic as well as systematic uncertainties stemming from the use of nucleon-nucleon interactions derived from chiral effective field theory at various orders. We therefore conclude that nuclear theory uncertainty is more likely not the source of the discrepancy. (c) 2018 The Authors. Published by Elsevier B.V.
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