6,643 research outputs found
Evolution of edge states in topological superfluids during the quantum phase transition
The quantum phase transition between topological and non-topological
insulators or between fully gapped superfluids/superconductors can occur
without closing the gap. We consider the evolution of the Majorana edge states
on the surface of topological superconductor during transition to the
topologically trivial superconductor on example of non-interacting Hamiltonian
describing the spin-triplet superfluid 3He-B. In conventional situation when
the gap is nullified at the transition, the spectrum of Majorana fermions
shrinks and vanishes after the transition to the trivial state. If the
topological transition occurs without the gap closing, the Majorana fermion
spectrum disappears by escaping to ultraviolet, where Green's function
approaches zero. This demonstrates the close connection between the topological
transition without closing the gap and zeroes in the Green's function. Similar
connection takes place in interacting systems where zeroes may occur due to
interaction.Comment: 5 pages, 2 figures, JETP Letters style, version submitted to JETP
Letter
Measurements of the Cross Section for e+e- -> hadrons at Center-of-Mass Energies from 2 to 5 GeV
We report values of for 85 center-of-mass energies between
2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing
Electron-Positron Collider.Comment: 5 pages, 3 figure
Electronic structure of the trilayer cuprate superconductor BiSrCaCuO
The low-energy electronic structure of the trilayer cuprate superconductor
BiSrCaCuO near optimal doping is investigated by
angle-resolved photoemission spectroscopy. The normal state quasiparticle
dispersion and Fermi surface, and the superconducting d-wave gap and coherence
peak are observed and compared with those of single and bilayer systems. We
find that both the superconducting gap magnitude and the relative
coherence-peak intensity scale linearly with for various optimally doped
materials. This suggests that the higher of the trilayer system should be
attributed to parameters that simultaneously enhance phase stiffness and
pairing strength.Comment: 5 pages, 5 figre
Sudden drop of fractal dimension of electromagnetic emissions recorded prior to significant earthquake
The variation of fractal dimension and entropy during a damage evolution
process, especially approaching critical failure, has been recently
investigated. A sudden drop of fractal dimension has been proposed as a
quantitative indicator of damage localization or a likely precursor of an
impending catastrophic failure. In this contribution, electromagnetic emissions
recorded prior to significant earthquake are analysed to investigate whether
they also present such sudden fractal dimension and entropy drops as the main
catastrophic event is approaching. The pre-earthquake electromagnetic time
series analysis results reveal a good agreement to the theoretically expected
ones indicating that the critical fracture is approaching
Measurement of azimuthal asymmetries in inclusive charged dipion production in annihilations at = 3.65 GeV
We present a measurement of the azimuthal asymmetries of two charged pions in
the inclusive process based on a data set of 62
at the center-of-mass energy GeV collected with
the BESIII detector. These asymmetries can be attributed to the Collins
fragmentation function. We observe a nonzero asymmetry, which increases with
increasing pion momentum. As our energy scale is close to that of the existing
semi-inclusive deep inelastic scattering experimental data, the measured
asymmetries are important inputs for the global analysis of extracting the
quark transversity distribution inside the nucleon and are valuable to explore
the energy evolution of the spin-dependent fragmentation function.Comment: 7 pages, 5 figure
Measurement of the Cross Section between 600 and 900 MeV Using Initial State Radiation
We extract the cross section in the energy
range between 600 and 900 MeV, exploiting the method of initial state
radiation. A data set with an integrated luminosity of 2.93 fb taken at
a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII
collider is used. The cross section is measured with a systematic uncertainty
of 0.9%. We extract the pion form factor as well as the
contribution of the measured cross section to the leading order hadronic vacuum
polarization contribution to . We find this value to be
.Comment: 14 pages, 7 figures, accepted by PL
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
Study of
We present an analysis of the decay based
on data collected by the BESIII experiment at the resonance. Using
a nearly background-free sample of 18262 events, we measure the branching
fraction . For GeV/ the partial branching fraction is
. A partial wave analysis shows that the dominant
component is accompanied by an \emph{S}-wave contribution accounting for
of the total rate and that other components are
negligible. The parameters of the resonance and of the
form factors based on the spectroscopic pole dominance predictions are also
measured. We also present a measurement of the helicity
basis form factors in a model-independent way.Comment: 17 pages, 6 figure
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