Phys Rev Lett
Paul Scherrer Institute, Villigen, Switzerland.
Published: November 2023
Models that postulate the existence of hidden sectors address contemporary questions, such as the source of baryogenesis and the nature of dark matter. Neutron-to-hidden-neutron oscillations are among the possible mixing processes and have been tested with ultracold neutron storage and passing-through-wall experiments to set constraints on the oscillation period τ_{nn^{'}}. These searches probe the oscillations as a function of the mass splitting due to the neutron-hidden-neutron energy degeneracy. In this work, we present a new limit derived from neutron disappearance in ultracold neutron beam experiments. The overall limit, given by τ_{nn^{'}}>1 s for |δm|∈[2,69] peV(95.45% C.L.), covers the yet unexplored intermediate mass-splitting range and contributes to the ongoing research on hidden sectors.
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http://dx.doi.org/10.1103/PhysRevLett.131.191801 | DOI Listing |
Nature
November 2024
Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Innsbruck, Austria.
Supersolids are states of matter that spontaneously break two continuous symmetries: translational invariance owing to the appearance of a crystal structure and phase invariance owing to phase locking of single-particle wavefunctions, responsible for superfluid phenomena. Although originally predicted to be present in solid helium, ultracold quantum gases provided a first platform to observe supersolids, with particular success coming from dipolar atoms. Phase locking in dipolar supersolids has been investigated through, for example, measurements of the phase coherence and gapless Goldstone modes, but quantized vortices, a hydrodynamic fingerprint of superfluidity, have not yet been observed.
View Article and Find Full Text PDFRev Sci Instrum
October 2024
North Carolina State University, Raleigh, North Carolina 27695, USA.
The upcoming UCNProBe experiment at Los Alamos National Laboratory will measure the beta decay rate of free neutrons with different systematic uncertainties than previous beam-based neutron lifetime experiments. We have tested a new 10B-coated Yttrium Aluminum Perovskite (YAP:Ce) scintillator and present its properties. The advantages of the YAP:Ce scintillator include its high Fermi potential, which reduces the probability for upscattering of ultracold neutrons (UCN), and its short decay time, which increases sensitivity at high counting rates.
View Article and Find Full Text PDFPNAS Nexus
May 2024
Academic Computer Centre CYFRONET, AGH University of Krakow, Ulica Nawojki 11, 30-950 Cracow, Poland.
Ultracold atoms provide a platform for analog quantum computer capable of simulating the quantum turbulence that underlies puzzling phenomena like pulsar glitches in rapidly spinning neutron stars. Unlike other platforms like liquid helium, ultracold atoms have a viable theoretical framework for dynamics, but simulations push the edge of current classical computers. We present the largest simulations of fermionic quantum turbulence to date and explain the computing technology needed, especially improvements in the Eigenvalue soLvers for Petaflop Applications library that enable us to diagonalize matrices of record size (millions by millions).
View Article and Find Full Text PDFRev Sci Instrum
April 2024
North Carolina State University, Raleigh, North Carolina 27695, USA.
A study of the dead layer thickness and quenching factor of a plastic scintillator for use in ultracold neutron (UCN) experiments is described. Alpha spectroscopy was used to determine the thickness of a thin surface dead layer to be 630 ± 110 nm. The relative light outputs from the decay of 241Am and Compton scattering of electrons were used to extract Birks' law coefficient, yielding a kB value of 0.
View Article and Find Full Text PDFACS Nano
March 2024
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
The strong nuclear force gives rise to the widely studied neutron scattering states and MeV-energy nuclear bound states. Whether this same interaction could lead to low-energy bound states for a neutron in the nuclear force field of a cluster of nuclei is an open question. Here, we computationally demonstrate the existence of μeV-level neutronic bound states originating from the strong interactions in nanocrystals with a spatial extent of tens of nanometers.
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