Early signal of emerging nuclear collectivity in neutron-rich $^{129}$SbGray, T. J.;Allmond, J. M.;Stuchbery, A. E.;Yu, C. -H.;Baktash, C.;Gargano, A.;Galindo-Uribarri, A.;Radford, D. C.;Batchelder, J. C.;Beene, J. R.;Bingham, C. R.;Coraggio, L.;Covello, A.;Danchev, M.;Gross, C. J.;Hausladen, P. A.;Itaco, N.;Krolas, W.;Liang, J. F.;Padilla-Rodal, E.;Pavan, J.;Stracener, D. W.;Varner, R. L.
doi: 10.1103/PhysRevLett.124.032502pmid: 32031845
Abstract: Radioactive $^{129}$Sb, which can be treated as a proton plus semi-magic $^{128}$Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, $B(E2)$, for the $2^+$ $\times$ $\pi g_{7/2}$ multiplet members and candidate $\pi d_{5/2}$ state were measured. The results indicate that the total electric quadrupole strength of $^{129}$Sb is a factor of 1.39(11) larger than the $^{128}$Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wavefunctions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.
Measuring the Weak Mixing Angle in the DUNE Near Detector Complexde Gouvêa, André;Machado, Pedro A. N.;Perez-Gonzalez, Yuber F.;Tabrizi, Zahra
doi: 10.1103/PhysRevLett.125.051803pmid: 32794872
Abstract: The planned DUNE experiment will have excellent sensitivity to the vector and axial couplings of the electron to the $Z$-boson via precision measurements of neutrino--electron scattering. We investigate the sensitivity of DUNE-PRISM, a movable near detector in the direction perpendicular to the beam line, and find that it will qualitatively impact our ability to constrain the weak couplings of the electron. We translate these neutrino--electron scattering measurements into a determination of the weak mixing angle at low scales and estimate that, with seven years of data taking, the DUNE near-detector can be used to measure $\sin^2\theta_W$ with about 2\% precision. We also discuss the impact of combining neutrino--electron scattering data with neutrino trident production at DUNE-PRISM.
Soliton Random Walk and the Cluster-Stripping Problem in Ultralight Dark MatterSchive, Hsi-Yu;Chiueh, Tzihong;Broadhurst, Tom
doi: 10.1103/PhysRevLett.124.201301pmid: 32501081
Abstract: Simulations of ultralight, $\sim 10^{-22}\,\rm eV$, bosonic dark matter exhibit rich wave-like structure, including a soliton core within a surrounding halo that continuously self-interferes on the de Broglie scale. We show here that as an inherent consequence, the soliton undergoes a confined random walk at the base of the halo potential. This is significant for the fate of the ancient central star cluster in Eridanus II, as the agitated soliton gravitationally shakes the star cluster in and out of the soliton on a time scale of $\sim 100\,\rm Myr$, so complete tidal disruption of the star cluster can occur within $\sim 1\,\rm Gyr$. This destructive effect can be mitigated by tidal stripping of the halo of Eridanus II, thereby reducing the agitation, depending on its orbit around the Milky Way. Our simulations show the Milky Way tide affects the halo much more than the soliton, so the star cluster in Eridanus II can survive for over $5\,\rm Gyr$ within the soliton if it formed after significant halo stripping.
Postmerger Gravitational-Wave Signatures of Phase Transitions in Binary MergersWeih, Lukas R.;Hanauske, Matthias;Rezzolla, Luciano
doi: 10.1103/PhysRevLett.124.171103pmid: 32412268
Abstract: With the first detection of gravitational waves from a binary system of neutron stars, GW170817, a new window was opened to study the properties of matter at and above nuclear-saturation density. Reaching densities a few times that of nuclear matter and temperatures up to $100\,\rm{MeV}$, such mergers also represent potential sites for a phase transition (PT) from confined hadronic matter to deconfined quark matter. While the lack of a postmerger signal in GW170817 has prevented us from assessing experimentally this scenario, two theoretical studies have explored the postmerger gravitational-wave signatures of PTs in mergers of binary systems of neutron stars. We here extend and complete the picture by presenting a novel signature of the occurrence of a PT. More specifically, using fully general-relativistic hydrodynamic simulations and employing a suitably constructed equation of state that includes a PT, we present the occurrence of a "delayed PT", i.e. a PT that develops only some time after the merger and produces a metastable object with a quark-matter core, i.e. a hypermassive hybrid star. Because in this scenario, the postmerger signal exhibits two distinct fundamental gravitational-wave frequencies -- before and after the PT -- the associated signature promises to be the strongest and cleanest among those considered so far, and one of the best signatures of the production of quark matter in the present Universe.
Manifestly Lorentz invariant chiral boson actionTownsend, Paul K.
doi: 10.1103/PhysRevLett.124.101604pmid: 32216380
Abstract: A manifestly Lorentz invariant action is found for the Floreanini-Jackiw chiral boson. The method involves a novel chiral reduction of the phase-space action for a string, and can be adapted to describe chiral bosons on the heterotic string worldsheet. A similar manifestly Lorentz invariant action is found for an entire class of conformal chiral 2k-form electrodynamics in (4k+2) dimensions which includes the Floreanini-Jackiw theory as the k=0$ case.
Energy of the $^{229}$Th Nuclear Clock Isomer Determined by Absolute $\gamma$-ray Energy DifferenceYamaguchi, A.;Muramatsu, H.;Hayashi, T.;Yuasa, N.;Nakamura, K.;Takimoto, M.;Haba, H.;Konashi, K.;Watanabe, M.;Kikunaga, H.;Maehata, K.;Yamasaki, N. Y.;Mitsuda, K.
doi: 10.1103/PhysRevLett.123.222501pmid: 31868403
Abstract: The low-lying isomeric state of $^{229}$Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric state by taking the absolute energy difference between the excitation energy required to populate the 29.2-keV state from the ground-state and the energy emitted in its decay to the isomeric excited state. A transition-edge sensor microcalorimeter was used to measure the absolute energy of the 29.2-keV $\gamma$-ray. Together with the cross-band transition energy (29.2 keV$\to$ground) and the branching ratio of the 29.2-keV state measured in a recent study, the isomer energy was determined to be 8.30$\pm$0.92 eV. Our result is in agreement with latest measurements based on different experimental techniques, which further confirms that the isomeric state of $^{229}$Th is in the laser-accessible vacuum ultraviolet range.
Explosive higher-order Kuramoto dynamics on simplicial complexesMillán, Ana P.;Torres, Joaquín J.;Bianconi, Ginestra
doi: 10.1103/PhysRevLett.124.218301pmid: 32530670
Abstract: The higher-order interactions of complex systems, such as the brain are captured by their simplicial complex structure and have a significant effect on dynamics. However, the existing dynamical models defined on simplicial complexes make the strong assumption that the dynamics resides exclusively on the nodes. Here we formulate the higher-order Kuramoto model which describes the interactions between oscillators placed not only on nodes but also on links, triangles, and so on. We show that higher-order Kuramoto dynamics can lead to an explosive synchronization transition by using an adaptive coupling dependent on the solenoidal and the irrotational component of the dynamics.