242 research outputs found
Radial Excitations of Heavy Mesons
Recent discovery of D_s states suggests existence of radial excitations. Our
semirelativistic quark potential model succeeds in reproducing these staes
within one to two percent of accuracy compared with the experiments, D_s0(2860)
and D_s^*(2715), which are identified as 0^+ and 1^- radial excitations (n=2).
We also present calculations of radial excitations for B/B_s heavy mesons.
Relation between our formulation and the modified Goldberger-Treiman relation
is also described.Comment: 3 pages, 1 figure, QNP06 conference repor
First-principles study on field evaporation for silicon atom on Si(001) surface
The simulations of field-evaporation processes for silicon atoms on various
Si(001) surfaces are implemented using the first-principles calculations based
on the real-space finite-difference method. We find that the atoms which locate
on atomically flat Si(001) surfaces and at step edges are easily removed by
applying external electric field, and the threshold value of the external
electric field for evaporation of atoms on atomically flat Si(001) surfaces,
which is predicted between 3.0 and 3.5 V/\AA, is in agreement with the
experimental data of 3.8 V/\AA. In this situation, the local field around an
evaporating atom does not play a crucial role. This result is instead
interpreted in terms of the bond strength between an evaporating atom and
surface.Comment: 5 pages and 4 figure
Determination of fragmentation functions and their uncertainties from e+ + e- -> h + X data
Fragmentation functions are determined for pions, kaons, and nucleons by a
global analysis of charged-hadron production data in electron-positron
annihilation. The optimum functions are obtained in both leading order (LO) and
next-to-leading order (NLO) of alpha_s. It is important that uncertainties of
the fragmentation functions are estimated in this work by the Hessian method.
We found that the uncertainties are large at small Q^2 and that they are
generally reduced in the NLO in comparison with the LO ones. We supply a code
for calculating the fragmentation functions and their uncertainties for the
pions, kaons, and nucleons at given z and Q^2.Comment: 4 pages, LaTeX, 5 eps files, to be published in AIP proceedings of
the 17th International Spin Physics Symposium (SPIN2006), Oct. 2-7, 2006,
Kyoto, Japa
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