2,029 research outputs found
Measurement of the half-life of the T= mirror decay of Ne and its implication on physics beyond the standard model
The superallowed mixed mirror decay
of Ne to F is excellently suited for high precision studies of
the weak interaction. However, there is some disagreement on the value of the
half-life. In a new measurement we have determined this quantity to be
= s, which differs
from the previous world average by 3 standard deviations. The impact of this
measurement on limits for physics beyond the standard model such as the
presence of tensor currents is discussed.Comment: 5 pages, 3 figures, 1 tabl
On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra Ions
As an important step towards an atomic parity violation experiment in one
single trapped Ra ion, laser spectroscopy experiments were performed with
on-line produced short-lived Ra ions. The isotope shift of
the 6\,^2D\,-\,7\,^2P and
6\,^2D\,-\,7\,^2P transitions and the hyperfine structure
constant of the 7\,^2S and 6\,^2D states in Ra
were measured. These values provide a benchmark for the required atomic theory.
A lower limit of ms for the lifetime of the metastable
6\,^2D state was measured by optical shelving.Comment: 4.2 pages, 6 figures, 2 tables
Non-Hermitian quantum mechanics in non-commutative space
We study non Hermitian quantum systems in noncommutative space as well as a
\cal{PT}-symmetric deformation of this space. Specifically, a
\mathcal{PT}-symmetric harmonic oscillator together with iC(x_1+x_2)
interaction is discussed in this space and solutions are obtained. It is shown
that in the \cal{PT} deformed noncommutative space the Hamiltonian may or may
not possess real eigenvalues depending on the choice of the noncommutative
parameters. However, it is shown that in standard noncommutative space, the
iC(x_1+x_2) interaction generates only real eigenvalues despite the fact that
the Hamiltonian is not \mathcal{PT}-symmetric. A complex interacting
anisotropic oscillator system has also been discussed.Comment: 5 pages, revised versio
Production of short lived radioactive beams of radium
Short lived Ra isotopes have been produced at the TRIP
facility in inverse kinematics via the fusion-evaporation reaction
Pb+C at 8 MeV/u. Isotopes are separated from other reaction
products online using the TRIP magnetic separator. The energetic radium
(Ra) isotopes at the exit of the separator were converted into low energy ions
with a thermal ionizer. Ra isotopes have been identified by observing their
decay and life times.Comment: 9 pages including 4 figures and 1 tabl
On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra Ions
As an important step towards an atomic parity violation experiment in one single trapped Ra ion, laser spectroscopy experiments were performed with on-line produced short-lived Ra ions. The isotope shift of the 6\,^2D\,-\,7\,^2P and 6\,^2D\,-\,7\,^2P transitions and the hyperfine structure constant of the 7\,^2S and 6\,^2D states in Ra were measured. These values provide a benchmark for the required atomic theory. A lower limit of ms for the lifetime of the metastable 6\,^2D state was measured by optical shelving
Spiral spin-liquid and the emergence of a vortex-like state in MnScS
Spirals and helices are common motifs of long-range order in magnetic solids,
and they may also be organized into more complex emergent structures such as
magnetic skyrmions and vortices. A new type of spiral state, the spiral
spin-liquid, in which spins fluctuate collectively as spirals, has recently
been predicted to exist. Here, using neutron scattering techniques, we
experimentally prove the existence of a spiral spin-liquid in MnScS by
directly observing the 'spiral surface' - a continuous surface of spiral
propagation vectors in reciprocal space. We elucidate the multi-step ordering
behavior of the spiral spin-liquid, and discover a vortex-like triple-q phase
on application of a magnetic field. Our results prove the effectiveness of the
- Hamiltonian on the diamond lattice as a model for the spiral
spin-liquid state in MnScS, and also demonstrate a new way to realize a
magnetic vortex lattice.Comment: 10 pages, 11 figure
Impact of Zn substitution on phase formation and superconductivity of Bi1.6Pb0.4 Sr2Ca2Cu3-xZnxO10 with x = 0.0, 0.015, 0.03, 0.06, 0.09 and 0.12
Samples of series Bi1.6Pb0.4Sr2Ca2Cu3-xZnxO10 with x = 0.0, 0.015, 0.03,
0.06, 0.09 and 0.12 are synthesized by solid-state reaction route. All the
samples crystallize in tetragonal structure with majority (> 90%) of Bi-2223
(Bi2Sr2Ca2Cu3O10) phase (c-lattice parameter ~ 36 A0). The proportion of
Bi-2223 phase decreases slightly with an increase in x. The lattice parameters
a and c of main phase (Bi-2223) do not change significantly with increasing x.
Superconducting critical transition temperature (Tc) decreases with x as
evidenced by both resistivity [(T)] and AC magnetic susceptibility [(T)]
measurements. Interestingly the decrement of Tc is not monotonic and the same
saturates at around 96 K for x > 0.06. In fact Tc decreases fast (~10K/at%) for
x = 0.015 and 0.03 samples and later nearly saturates for higher x values.
Present results of Zn doping in Bi-2223 system are compared with Zn doped other
HTSC (High temperature superconducting) systems, namely the RE-123 (REBa2Cu3O7)
and La-214 ((La,Sr)2CuO4).Comment: 12, pages of text and Figs. TO APPEAR IN Mod. Phys. Lett. B (2005)
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