1,848 research outputs found
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
Substantial gain enhancement for optical parametric amplification and oscillation in two-dimensional χ(2) nonlinear photonic crystals
We have analyzed optical parametric interaction in a 2D NPC. While in general the nonlinear coefficient is small compared to a 1D NPC, we show that at numerous orientations a multitude of reciprocal vectors contribute additively to enhance the gain in optical parametric amplification and oscillation in a 2D patterned crystal. In particular, we have derived the effective nonlinear coefficients for common-signal amplification and common-idler amplification for a tetragonal inverted domain pattern. We show that in the specific case of signal amplification with QPM by both G10 and G11, symmetry of the crystal results in coupled interaction with the corresponding signal amplification by G10 and G1,-1. As a consequence, this coupled utilization of all three reciprocal vectors leads to a substantial increase in parametric gain. Using PPLN we demonstrate numerically that a gain that comes close to that of a 1D QPM crystal could be realized in a 2D NPC with an inverted tetragonal domain pattern. This special mechanism produces two pairs of identical signal and idler beams propagating in mirror-imaged forward directions. In conjunction with this gain enhancement and multiple beams output we predict that there is a large pulling effect on the output wavelength due to dynamic signal build-up in the intrinsic noncollinear geometry of a 2D NPC OPO
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
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
Flight to Quality for Large Financial Institutions
Local correlation analysis is used to investigate flight to quality among large financial institutions before, during, and after the financial crisis of 2008-2009. While standard correlation captures general overall linear association, local correlation analysis more accurately captures changes in the associations in response to changing market conditions. Using raw, market-adjusted, and industry-adjusted stock returns of individual banks, we investigate the performance of troubled banks and the change in investing behavior. Investors react to noisy information from the financial difficulties encountered by banking institutions. This reaction results in flight to quality. While the traditional Pearson correlations capture general overall linear association, local correlation analysis captures changes in the association in response to changing market conditions. Thus, local correlation analysis more accurately measures changes in correlation where it matters most: in the loss tail of the distribution of financial returns; leading to more appropriate diversification, portfolio management, and within-industry implications
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.
Estimate of the Hadronic Production of the Doubly Charmed Baryon under GM-VFN Scheme
Hadronic production of the doubly charmed baryon (
and ) is investigated under the general-mass
variable-flavor-number (GM-VFN) scheme. The gluon-gluon fusion mechanism and
the intrinsic charm mechanisms, i.e. via the sub-processes
,
; ,
and , , are taken into account in the investigation, where
(in color {\bf }) and (in color
{\bf 6}) are two possible -wave configurations of the doubly charmed diquark
pair inside the baryon . Numerical results for the production
at hadornic colliders LHC and TEVATRON show that both the contributions from
the doubly charmed diquark pairs and are
sizable with the assumption that the two NRQCD matrix elements are equal, and
the total contributions from the `intrinsic' charm mechanisms are bigger than
those of the gluon-gluon fusion mechanism. For the production in the region of
small transverse-momentum , the intrinsic mechanisms are dominant over the
gluon-gluon fusion mechanism and they can raise the theoretical prediction of
the by almost one order.Comment: 26 pages, 8 figure
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