551 research outputs found
The Instantaneous Bethe-Salpeter Equation and Its Analog: the Breit-like Equation
We take () systems and consider the states with quantum number
as examples, to explore the different contents of the instantaneous
Bethe-Salpeter (BS) equation and its analog, Breit equation, by solving them
exactly. The results show that the two equations are not equivalent, although
they are analogous. Furthermore, we point out that the Breit equation contains
extra un-physical solutions, so it should be abandoned if one wishes to have an
accurate description of the bound states for the instantaneous interacting
binding systems.Comment: 5 pages, no figur
Hadronic production of the -wave excited -states ()
Adopting the complete approach of the perturbative QCD (pQCD)
and updated parton distribution functions, we have estimated the hadronic
production of -wave excited -states (). In the estimate,
special care on the relation of the production amplitude to the derivative of
wave function at origin of the potential model is payed. For experimental
references, main uncertainties are discussed, and the total cross sections and
the distributions of the production with reasonable cuts at the energies of
Tevatron and LHC are computed and presented. The results show that -wave
production may contribute to the -meson production indirectly by a factor
about 0.5 of the direct production, and with such a big cross section, it is
worth further to study the possibility to observe the -wave production
itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec
Decays of the Meson to a -Wave Charmonium State or
The semileptonic decays,
, and the two-body
nonleptonic decays, , (here and
denote and respectively, and
indicates a meson) were computed. All of the form factors appearing in the
relevant weak-current matrix elements with as its initial state and a
-wave charmonium state as its final state for the decays were precisely
formulated in terms of two independent overlapping-integrations of the
wave-functions of and the -wave charmonium and with proper kinematics
factors being `accompanied'. We found that the decays are quite sizable, so
they may be accessible in Run-II at Tevatron and in the foreseen future at LHC,
particularly, when BTeV and LHCB, the special detectors for B-physics, are
borne in mind. In addition, we also pointed out that the decays may potentially be used as a fresh window to look for the
charmonium state, and the cascade decays,
() with one of the radiative decays
being followed accordingly, may affect
the observations of meson through the decays () substantially.Comment: 24 pages, 3 figures, the replacement for improving the presentation
and adding reference
The meson annihilation to leptons and inclusive light hadrons
The annihilation of the meson to leptons and inclusive light hadrons is
analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find
that the decay mode, which escapes from the helicity suppression, contributes a
sizable fraction width. According to the analysis, the branching ratio due to
the contribution from the color-singlet component of the meson can be of
order (10^{-2}). We also estimate the contributions from the color-octet
components. With the velocity scaling rule of NRQCD, we find that the
color-octet contributions are sizable too, especially, in certain phase space
of the annihilation they are greater than (or comparative to) the color-singlet
component. A few observables relevant to the spectrum of charged lepton are
suggested, that may be used as measurements on the color-octet and
color-singlet components in the future experiments. A typical long
distance contribution in the annihilation is estimated too.Comment: 26 pages, 5 figures (6 eps-files), submitted to Phys. Rev.
The Color-Octet Contributions to -wave Meson Hadroproduction
The contributions from the color-octet components and to the or
(the -wave meson) hadroproduction are estimated in
terms of the complete calculation. As necessary inputs
in the estimate, we take the values of the octet matrix elements according to
the NRQCD scaling rules, and as a result, we have found that the contributions
to the -wave production may be the same in order of magnitude as those from
the color-singlet ones, and (). Especially, our result indicates that the
observation of the color-octet contributions to the -wave production in the
low transverse momentum region is not very far from the present experimental
capability at Tevatron and LHC.Comment: 14 pages, 4 figures (8 eps-files for figures), add references and
correct typo
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