930 research outputs found
Effective field theory of the deuteron with dibaryon field
Pionless effective field theory with dibaryon fields is reexamined for
observables involving the deuteron. The electromagnetic form factors of the
deuteron and the total cross sections of radiative neutron capture on the
proton, , are calculated. The low energy constants of
vector(photon)-dibaryon-dibaryon vertices in the effective lagrangian are fixed
primarily by the one-body vector(photon)-nucleon-nucleon interactions. This
scheme for fixing the values of the low energy constants satisfactorily
reproduces the results of the effective range theory. We also show that, by
including higher order corrections, one can obtain results that are close to
those of Argonne v18 potential model.Comment: 25 pages and 11 figures; 16 references added, Figure 6 and 7
replotted, text revised a lot. To be published in Phys. Rev.
Low energy proton-proton scattering in effective field theory
Low energy proton-proton scattering is studied in pionless effective field
theory. Employing the dimensional regularization and MS-bar and power
divergence subtraction schemes for loop calculation, we calculate the
scattering amplitude in 1S0 channel up to next-to-next-to leading order and fix
low-energy constants that appear in the amplitude by effective range
parameters. We study regularization scheme and scale dependence in separation
of Coulomb interaction from the scattering length and effective range for the
S-wave proton-proton scattering.Comment: 23 pages, 6 eps figures, revised considerably, accepted for
publication in Phys. Rev.
Critical behavior of two-dimensional random hopping fermions with \pi-flux
A two dimensional random hopping model with N-species and \pi-flux is
studied. The field theory at the band center is shown to be in the universality
class of GL(4m,R)/O(4m) nonlinear sigma model. Vanishing beta function suggests
delocalised states at the band center. Contrary to the similar universality
class with broken time reversal symmetry, the present class is expected to have
at least two fixed point. Large N-systems are shown to be in the weak-coupling
fixed point, which is characterized by divergent density of state, while small
N systems may be in the strong-coupling fixed point.Comment: 12 pages, revtex, 1 figur
Five-body resonances of 8He using the complex scaling method
The 0+ states of 8He are studied in a five-body 4He+n+n+n+n cluster model.
Many-body resonances are treated on the correct boundary condition as Gamow
states using the complex scaling method. The 0+_2 state of 8He is predicted as
a five-body resonance in the excitation energy of 6.3 MeV with a width of 3.2
MeV, which mainly has a (p_{3/2})^2(p_{1/2})^2 configuration. In this state,
number of the 0+ neuron pair shows almost two, which is different from the
ground state having a large amount of the 2+ pair component. The monopole
transition of 8He from the ground state into the five-body unbound states is
also evaluated. It is found that the 7He+n component mostly exhausts the
strength, while the 0+_2 contribution is negligible. The final states are
dominated by 6He+n+n, not 4He+n+n+n+n. The results indicate the sequential
breakup process of 8He to 7He+n to 6He+n+n by the monopole excitation.Comment: 6 pages, 6 figures, table I is updated for the experimental value
Three-parameter Lorentz-violating texture for neutrino mixing
A three-parameter model of neutrino oscillations based on a simple Lorentz-
and CPT-violating texture is presented. The model is consistent with
established data and naturally generates low-energy and neutrino-antineutrino
anomalies of the MiniBooNE type. A one-parameter extension incorporates the
MINOS anomaly, while a simple texture enhancement accommodates the LSND signal.Comment: 5 pages, accepted for publication in Physics Letters
Finding of Probable Tsunami Boulders on Jiupeng Coast in Southeastern Taiwan
We find three coral boulders (approx. 5 m across) resting on the Holocene coral terrace on the Jiupeng coast of southeastern Taiwan. Three exotic corals on the outer part of the boulders are dated at ca. 5000 yr BP which is similar to that of in situ corals composing the Holocene terrace. We interpret that these boulders were broken off from the coral terrace and were transported by tsunami waves, although the timing of the paleotsunami is not determined at this stage
Monotonic growth of interlayer magnetoresistance in strong magnetic field in very anisotropic layered metals
It is shown, that the monotonic part of interlayer electronic conductivity
strongly decreases in high magnetic field perpendicular to the conducting
layers. We consider only the coherent interlayer tunnelling, and the obtained
result strongly contradicts the standard theory. This effect appears in very
anisotropic layered quasi-two-dimensional metals, when the interlayer transfer
integral is less than the Landau level separation.Comment: 4 pages, no figure
Multisite tyrosine phosphorylation of the N-terminus of Mint1/X11α by Src kinase regulates the trafficking of amyloid precursor protein
Mint1/X11α is one of four neuronal trafficking adaptors that interact with amyloid precursor protein (APP) and are linked with its cleavage to generate Aβ peptide, a key player in the pathology of Alzheimer's disease. How APP switches between adaptors at different stages of the secretory pathway is poorly understood. Here we show that tyrosine phosphorylation of Mint1 regulates the destination of APP. A canonical SH2 binding motif ((202) YEEI) was identified in the N-terminus of Mint1 that is phosphorylated on tyrosine by C-Src and recruits the active kinase for sequential phosphorylation of further tyrosines (Y191 and Y187). A single Y202F mutation in the Mint1 N-terminus inhibits C-Src binding and tyrosine phosphorylation. Previous studies observed that co-expression of wild type Mint1 and APP causes accumulation of APP in the trans-Golgi. Unphosphorylatable Mint1 (Y202F) or pharmacological inhibition of Src reduced the accumulation of APP in the trans-Golgi of heterologous cells. A similar result was observed in cultured rat hippocampal neurons where Mint1(Y202F) permitted the trafficking of APP to more distal neurites than the wild type protein. These data underline the importance of the tyrosine phosphorylation of Mint1 as a critical switch for determining the destination of APP. This article is protected by copyright. All rights reserved
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