1,128 research outputs found
Third-order non-Coulomb correction to the S-wave quarkonium wave functions at the origin
We compute the third-order correction to the S-wave quarkonium wave functions
|\psi_n(0)|^2 at the origin from non-Coulomb potentials in the effective
non-relativistic Lagrangian. Together with previous results on the Coulomb
correction and the ultrasoft correction computed in a companion paper, this
completes the third-order calculation up to a few unknown matching
coefficients. Numerical estimates of the new correction for bottomonium and
toponium are given.Comment: 12 pages, v2: matches published version, missing factors in eq. (9),
(29) adde
Quarkonium production and NRQCD matrix elements
Most recent calculations of quarkonium production are based on the NRQCD
factorization formalism. This formalism is reviewed. To make predictions about
specific cross section, universal NRQCD matrix elements need to be extracted
from experiments. Extractions from different experimental situations are
compared, with some emphasis on the extraction from LEP.Comment: 6 pages, 1 figure, talk given at 4th International Conference on
Hyperons, Charm and Beauty Hadrons, Valencia, Spain, 27-30 Jun 200
Third-order Coulomb corrections to the S-wave Green function, energy levels and wave functions at the origin
We obtain analytic expressions for the third-order corrections due to the
strong interaction Coulomb potential to the S-wave Green function, energy
levels and wave functions at the origin for arbitrary principal quantum number
n. Together with the known non-Coulomb correction this results in the complete
spectrum of S-states up to order alpha_s^5. The numerical impact of these
corrections on the Upsilon spectrum and the top quark pair production cross
section near threshold is estimated.Comment: 24 pages, LaTeX, v2: eq.(30) corrected (-13/8->-15/8
SCET sum rules for heavy-to-light form factors
We consider a sum rule for heavy-to-light form factors in soft-collinear
effective theory (SCET). Using the correlation function given by the
time-ordered product of a heavy-to-light current and its hermitian conjugate,
the heavy-to-light soft form factor zeta_P can be related to the leading-order
B meson shape function. Using the scaling behavior of the heavy-to-light form
factor in Lambda_QCD/m_b, we put a constraint on the behavior of the meson
shape function near the endpoint. We employ the sum rule to estimate the size
of zeta_P with the model for the shape function and find that it ranges from
0.01 to 0.07.Comment: 11 pages, 5 figure
NNNLO correction to the toponium and bottomonium wave-functions at the origin
We report new results of the NNNLO correction to the S-wave quarkonium
wave-functions at the origin, which also provide an estimate of the resonance
cross section in t-tbar threshold production at the ILC.Comment: 5 pages, 2 figures, Proceedings of 2007 International Linear Collider
Workshop: LCWS07 and ILC07, Hamburg, Germany, 30 May - 3 Jun 200
B ->\eta_c K(\eta_c^\prime K) decays in QCD factorization
We study the exclusive decays of meson into pseudoscalar charmonium
states and within the QCD factorization approach and
find that the nonfactorizable corrections to naive factorization are infrared
safe at leading-twist order. The spectator interactions arising from the kaon
twist-3 effects are formally power-suppressed but chirally and logarithmically
enhanced. The theoretical decay rates are too small to accommodate the
experimental data. On the other hand, we compare the theoretical calculations
for , and , and find that the
predicted relative decay rates of these four states are approximately
compatible with experimental data.Comment: 8 pages, LaTex, 1 figure, one footnote and two references adde
B meson light-cone wavefunctions in the heavy quark limit
We present a systematic study of the B meson light-cone wavefunctions in QCD
in the heavy-quark limit. We construct model-independent formulae for the
light-cone wavefunctions in terms of independent dynamical degrees of freedom,
which exactly satisfy the QCD equations of motion and constraints from
heavy-quark symmetry. The results demonstrate novel behaviors of longitudinal
as well as transverse momentum distribution in the B mesons.Comment: 5 pages LaTeX, 1 style file. Talk presented at RADCOR/Loops and Legs
2002, Kloster Banz, Germany, September 8-13, 200
Charmless decays and the new physics effects in the minimal supergravity model
By employing the QCD factorization approach, we calculate the new physics
contributions to the branching radios of the two-body charmless
decays in the framework of the minimal supergravity (mSUGRA) model. Within the
considered parameter space, we find that (a) the supersymmetric (SUSY)
corrections to the Wilson coefficients () are very small and can
be neglected safely, but the leading order SUSY contributions to
and can be rather large and even change the
sign of the corresponding coefficients in the standard model; (b) the possible
SUSY contributions to those penguin-dominated decays in mSUGRA model can be as
large as ; (c) for the well measured decays, the
significant SUSY contributions play an important rule to improve the
consistency of the theoretical predictions with the data; (d) for decays, the theoretical predictions of the corresponding branching
ratios become consistent with the data within one standard deviation after the
inclusion of the large SUSY contributions in the mSUGRA model.Comment: 31 pages, Latex file, 4 ps and eps figures, minor corrections, final
version to appear in Physical Review
Radiative B decays to the axial mesons at next-to-leading order
We calculate the branching ratios of at next-to-leading
order (NLO) of where is the orbitally excited axial vector
meson. The NLO decay amplitude is divided into the vertex correction and the
hard spectator interaction part. The one is proportional to the weak form
factor of transition while the other is a convolution between
light-cone distribution amplitudes and hard scattering kernel. Using the
light-cone sum rule results for the form factor, we have \calB(B^0\to
K_1^0(1270)\gamma)=(0.828\pm0.335)\times 10^{-5} and \calB(B^0\to
K_1^0(1400)\gamma)=(0.393\pm0.151)\times 10^{-5}.Comment: 17pages, 4 figures. Minor changes, typos corrected. PRD accepted
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