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Full-Text Articles in Physics
Precision Determination Of The Neutral Weak Form Factor Of ^48ca, D. Adhikari, (...), David S. Armstrong, Et Al.
Precision Determination Of The Neutral Weak Form Factor Of ^48ca, D. Adhikari, (...), David S. Armstrong, Et Al.
Arts & Sciences Articles
We report a precise measurement of the parity-violating (PV) asymmetry APV in the elastic scattering of longitudinally polarized electrons from 48Ca. We measure APV=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor FW(q=0.8733 fm−1)=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor Fch−FW=0.0277±0.0055. The resulting neutron skin thickness Rn−Rp=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.
Beyond The Petermann Limit: Prospect Of Increasing Sensor Precision Near Exceptional Points, David D. Smith, Hongrok Chang, Eugeniy E. Mikhailov, Selim M. Shahriar
Beyond The Petermann Limit: Prospect Of Increasing Sensor Precision Near Exceptional Points, David D. Smith, Hongrok Chang, Eugeniy E. Mikhailov, Selim M. Shahriar
Arts & Sciences Articles
Experiments near the lock-in region in maximally dissipative non-Hermitian systems, e.g., conventional laser gyroscopes near the deadband, have run up against the Petermann limit, where excess noise exactly cancels any scale-factor enhancement resulting in no overall enhancement in precision. As a result, one might be tempted to conclude that exceptional points (EPs) generally cannot be used to increase the precision of laser sensors. Indeed, using a linear eigenmode analysis we show that the Petermann limit applies not just to maximally dissipative systems, but for any type of EP, owing to the fact that EPs are rotationally invariant. It turns out, …
Orbital-Selective Metallicity In The Valence-Bond Liquid Phase Of Li2 Ruo3, Patrick Mcardle, Fei-Ting Huang, Junjie Yang, (...), M. M. Qazilbash
Orbital-Selective Metallicity In The Valence-Bond Liquid Phase Of Li2 Ruo3, Patrick Mcardle, Fei-Ting Huang, Junjie Yang, (...), M. M. Qazilbash
Arts & Sciences Articles
Li2RuO3 (LRO) forms a valence bond crystal at room temperature. It undergoes a high temperature phase transition that involves structural, magnetic, and electronic changes leading to an exotic valence bond liquid state. The orbital degrees of freedom are thought to be fundamental to the evolution of LRO properties across the phase transition. We report temperature dependent broadband (100–26000cm–1) reflectance measurements on single crystals of LRO to elucidate structural and transport properties. Specifically, the phonon and electronic properties of LRO were investigated through the phase transition. We report that above the transition temperature (Tc≈500K), the optical band gap closes for electrons …
New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, D. Adhikari, (...), David S. Armstrong, Et Al.
New Measurements Of The Beam-Normal Single Spin Asymmetry In Elastic Electron Scattering Over A Range Of Spin-0 Nuclei, D. Adhikari, (...), David S. Armstrong, Et Al.
Arts & Sciences Articles
We report precision determinations of the beam-normal single spin asymmetries (An) in the elastic scattering of 0.95 and 2.18 GeV electrons off 12C, 40Ca, 48Ca, and 208Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of An for 40Ca and 48Ca are found to be similar to that of 12C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z≤20. We also report An for 208Pb at two new momentum transfers (Q2) extending the previous measurement. Our new data confirm the surprising result previously reported, with all …
Determination Of The ^27al Neutron Distribution Radius From A Parity-Violating Electron Scattering Measurement, D. Androic, David S. Armstrong, Et Al.
Determination Of The ^27al Neutron Distribution Radius From A Parity-Violating Electron Scattering Measurement, D. Androic, David S. Armstrong, Et Al.
Arts & Sciences Articles
We report the first measurement of the parity-violating elastic electron scattering asymmetry on 27Al. The 27Al elastic asymmetry is APV=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q2⟩=0.02357±0.00010 GeV2, ⟨θlab⟩=7.61°±0.02°, and ⟨Elab⟩=1.157 GeV with the Qweak apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the 27Al neutron radius Rn=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness Rn−Rp=−0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves …