While the international nEDM collaboration at the Paul Scherrer Institut (PSI) took data in 2017 that covered a considerable fraction of the parameter space of claimed potential signals of ...hypothetical neutron (n) to mirror-neutron (n′) transitions, it could not test all claimed signal regions at various mirror magnetic fields. Therefore, a new study of n−n′ oscillations using stored ultracold neutrons (UCNs) is underway at PSI, considerably expanding the reach in parameter space of mirror magnetic fields (B′) and oscillation time constants (τnn′). The new apparatus is designed to test for the anomalous loss of stored ultracold neutrons as a function of an applied magnetic field. The experiment is distinguished from its predecessors by its very large storage vessel (1.47 m3), enhancing its statistical sensitivity. In a test experiment in 2020 we have demonstrated the capabilities of our apparatus. However, the full analysis of our recent data is still pending. Based on already demonstrated performance, we will reach sensitivity to oscillation times τnn′/cos(β) well above a hundred seconds, with β being the angle between B′ and the applied magnetic field B. The scan of B will allow the finding or the comprehensive exclusion of potential signals reported in the analysis of previous experiments and suggested to be consistent with neutron to mirror-neutron oscillations.
Ultra-low-mass axions are a viable dark matter candidate and may form a coherently oscillating classical field. Nuclear spins in experiments on Earth might couple to this oscillating axion ...dark-matter field, when propagating on Earth’s trajectory through our Galaxy. This spin coupling resembles an oscillating pseudo-magnetic field which modulates the spin precession of nuclear spins. Here we report on the null result of a demonstration experiment searching for a frequency modulation of the free spin-precession signal of 199Hg in a magnetic field. Our search covers the axion mass range
10^{-16} \textrm{eV} \lesssim m_a \lesssim 10^{-13} \textrm{eV}
10
−
16
eV
≲
m
a
≲
10
−
13
eV
and achieves a peak sensitivity to the axion-nucleon coupling of
g_{aNN} \approx 3.5 \times 10^{-6} \textrm{GeV}^{-1}
g
a
N
N
≈
3.5
×
10
−
6
GeV
−
1
.
Four nucleon scattering at intermediate energies provides unique
opportunities to study effects of the two key ingredients of the nuclear
dynamics, the nucleon-nucleon P-wave (NNP-wave) and the ...three-nucleon
force (3NF). This is possible only with systematic and precise data, in
conjunction with exact theoretical calculations. Using the BINA detector
at KVI Groningen, the Netherlands, a rich set of differential cross
section of the
^{2}
2
H(d,dp)n breakup reaction at 160 MeV
deuteron beam energy has been measured. Besides the three-body breakup,
also cross sections of the
^{2}
2
H(d,
^{3}
3
He)n
proton transfer reaction have been obtained. The data are compared to
the recent calculations for the three-cluster breakup.
Deuteron breakup reactions are basic laboratories for testing nuclear force models. Recent improvements in the data analysis allow for direct identification of neutrons in the BINA detection setup. ...This opens up the opportunity to study new aspects of few-nucleon system dynamics like charge dependence of nuclear force or Coulomb interaction.
In this paper we determine regions along the kinematical curves where differential cross section of deuteron-proton breakup reactions can be measured by the proton-neutron and proton-proton coincidences simultaneously.
%In this paper we determine regions along the kinematical curves where differential cross section of $^1$H$(d,pp)n$ and $^1$H$(d,pn)p$ breakup reactions overlap.
This is particularly useful for validation of the neutron detection technique.
The~Space Star Anomaly in proton-deuteron breakup cross-section occurs at energies of about 10~MeV. Data for higher energies are sparse. Therefore, a~systematic scan over star configurations in ...the~range of intermediate energies between 50 and 100 MeV/nucleon is carried out on the~basis of data collected with the~large acceptance BINA detector.
The~preliminary cross section results for forward star configurations at 80 MeV/nucleon slightly surpass the~theoretical calculations, but the~systematic uncertainties are still under study.
Also, a~new variable describing rotation of star configurations is proposed.
PDF
