13,607 research outputs found
Analysis of B-> \phi K Decays in QCD Factorization
We analyze the decay within the framework of QCD-improved
factorization. We found that although the twist-3 kaon distribution amplitude
dominates the spectator interactions, it will suppress the decay rates
slightly. The weak annihilation diagrams induced by penguin
operators, which are formally power-suppressed by order , are
chirally and logarithmically enhanced. Therefore, these annihilation
contributions are not subject to helicity suppression and can be sizable. The
predicted branching ratio of is in
the absence of annihilation contributions and it becomes
when annihilation effects are taken into
account. The prediction is consistent with CLEO and BaBar data but smaller than
the BELLE result.Comment: 13 pages, 3 figures. A major change for the presentation of
branching-ratio predictions. Experimental data are update
Stabilizing yield and quality: early maturing chickpea for the prairies
Non-Peer ReviewedProgress in chickpea breeding has been constrained by lack of good sources of early maturity in the short-season temperate environment of western Canada. We hypothesized that the length of the chickpea life-cycle could be reduced through introgression of strategic genetic traits including short internode, double podding and early flowering. The result showed that both the double podding and early flowering traits had significant beneficial effects by reducing the duration of crop maturity in chickpea in the short-season temperate environment of western Canada. Pyramiding double podding, early flowering and other strategic genetic traits should lead to the development of extra short duration chickpea varieties more suited for cultivation in the Prairies and similar environments
Heavy to Light Meson Exclusive Semileptonic Decays in Effective Field Theory of Heavy Quark
We present a general study on exclusive semileptonic decays of heavy (B, D,
B_s) to light (pi, rho, K, K^*) mesons in the framework of effective field
theory of heavy quark. Transition matrix elements of these decays can be
systematically characterized by a set of wave functions which are independent
of the heavy quark mass except for the implicit scale dependence. Form factors
for all these decays are calculated consistently within the effective theory
framework using the light cone sum rule method at the leading order of 1/m_Q
expansion. The branching ratios of these decays are evaluated, and the heavy
and light flavor symmetry breaking effects are investigated. We also give
comparison of our results and the predictions from other approaches, among
which are the relations proposed recently in the framework of large energy
effective theory.Comment: 18 pages, ReVtex, 5 figures, added references and comparison of
results, and corrected signs in some formula
QCD factorization for B -> PP
In this work, we give a detailed discussion for QCD factorization involved
the complete chirally enhanced power corrections for B decays to two light
pseudoscalar mesons, and present some detailed calculations of radiative
corrections at the order of alpha_s. We point out that the infrared finiteness
of the vertex corrections in the chirally enhanced power corrections requires
twist-3 light-cone distribution amplitudes (LCDAs) of the light pseudoscalar
symmetric. However, even in the symmetric condition, there is also logarithmic
divergence from the endpoints of the twist-3 LCDAs in the hard spectator
scattering. We point out that the decay amplitudes of B --> PP predicted by QCD
factorization are really free of the renormalization scale dependence, at least
at the order of alpha_s. At last, we briefly compare the QCD factorization with
the generalized factorization and PQCD method.Comment: 31 pages, 3 eps figure
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MoonLITE – Technological feasibility of the penetrator concept
Introduction: While the surface missions to the Moon of the 1960s and 1970s achieved a great deal, scientifically a great deal was also left unresolved. The recent plethora of lunar missions (flown or proposed) reflects resurgence in interest in the Moon, not only in its own right, but also as a record of the formation of the Earth-Moon System and the interplanetary environment at 1 AU. Results from orbiter missions have indicated the possible presense of ice within permanently shaded craters at the lunar poles [1] – a situation that, if confirmed, will have profound impacts on lunar exploration
Testing the dynamics of high energy scattering using vector meson production
I review work on diffractive vector meson production in photon-proton
collisions at high energy and large momentum transfer, accompanied by proton
dissociation and a large rapidity gap. This process provides a test of the high
energy scattering dynamics, but is also sensitive to the details of the
treatment of the vector meson vertex.
The emphasis is on the description of the process by a solution of the
non-forward BFKL equation, i.e. the equation describing the evolution of
scattering amplitudes in the high-energy limit of QCD. The formation of the
vector meson and the non-perturbative modeling needed is also briefly
discussed.Comment: 17 pages, 8 figures. Brief review to appear in Mod. Phys. Lett.
Remarks on the KLS conjecture and Hardy-type inequalities
We generalize the classical Hardy and Faber-Krahn inequalities to arbitrary
functions on a convex body , not necessarily
vanishing on the boundary . This reduces the study of the
Neumann Poincar\'e constant on to that of the cone and Lebesgue
measures on ; these may be bounded via the curvature of
. A second reduction is obtained to the class of harmonic
functions on . We also study the relation between the Poincar\'e
constant of a log-concave measure and its associated K. Ball body
. In particular, we obtain a simple proof of a conjecture of
Kannan--Lov\'asz--Simonovits for unit-balls of , originally due to
Sodin and Lata{\l}a--Wojtaszczyk.Comment: 18 pages. Numbering of propositions, theorems, etc.. as appeared in
final form in GAFA seminar note
P-wave Quarkonium Decays to Meson Pairs
The processes of P-wave Quarkonium exclusive decays to two mesons are
investigated, in which the final state vector mesons with various polarizations
are considered separately. In the calculation, the initial heavy quarkonia are
treated in the framework of non-relativistic quantum chromodynamics, whereas
for light mesons, the light cone distribution amplitudes up to twist-3 are
employed. It turns out that the higher twist contribution is significant and
provides a possible explanation for the observation of the hadron helicity
selection rule violated processes
by the BESIII collaboration in recently. We also evaluate the process and find that its branching ratio is big enough to be
measured at the B-factories.Comment: more results and discussions adde
Exploring the Unitarity Triangle through CP violation observables in
We discuss the determination of the CKM parameters from the forthcoming
violation observables in decays. Combining the information on
mixing induced CP violation in , with the
precision observable and the -- mixing phase
, we propose a determination of the unitarity triangle . Computing the penguin parameters within QCD
factorization yield precise determination of , reflected
by a weak dependence on the which is shown as a second order effect.
The impact of the direct CP violation observable on the penguin
parameters are investigated and a lower bound on is extracted. We also
discuss the effect of the -- new physics mixing phase on
the penguin parameters and . Using the SU(3)-flavour
symmetry argument and the current -factories data provided by the modes, we complement the CP-violating
observables in a variety of ways, in particular we find that .
Finally we analyze systematically the SU(3)-symmetry breaking factor within QCD
factorization.Comment: 22 pages, 6 figures, typos corrected, reference and some remarks
adde
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