52,957 research outputs found
Bounds on gamma from CP violation measurements in B -> pi+ pi- and B -> psi K_S
We study the determination of gamma from CP-violating observables in B -> pi+
pi- and B -> psi K_S. This determination requires theoretical input to one
combination of hadronic parameters. We show that a mild assumption about this
quantity may allow bounds to be placed on gamma, but we stress the pernicious
effects that an eightfold discrete ambiguity has on such an analysis. The
bounds are discussed as a function of the direct (C) and interference (S)
CP-violating observables obtained from time-dependent B -> pi+ pi- decays, and
their behavior in the presence of new physics effects in B-Bbar mixing is
studied. (V2: Misprints corrected. Slightly improved discussion.)Comment: 11 pages, RevTex 4, 5 eps figures include
Non-commutative Quantum Mechanics in Three Dimensions and Rotational Symmetry
We generalize the formulation of non-commutative quantum mechanics to three
dimensional non-commutative space. Particular attention is paid to the
identification of the quantum Hilbert space in which the physical states of the
system are to be represented, the construction of the representation of the
rotation group on this space, the deformation of the Leibnitz rule accompanying
this representation and the implied necessity of deforming the co-product to
restore the rotation symmetry automorphism. This also implies the breaking of
rotational invariance on the level of the Schroedinger action and equation as
well as the Hamiltonian, even for rotational invariant potentials. For
rotational invariant potentials the symmetry breaking results purely from the
deformation in the sense that the commutator of the Hamiltonian and angular
momentum is proportional to the deformation.Comment: 21 page
Reparametrization invariance of B decay amplitudes and implications for new physics searches in B decays
When studying B decays within the Standard Model, it is customary to use the
unitarity of the CKM matrix in order to write the decay amplitudes in terms of
only two of the three weak phases which appear in the various diagrams.
Occasionally, it is mentioned that those two weak phases can be used in order
to describe any decay amplitude, even beyond the Standard Model. Here we point
out that, when describing a generic decay amplitude, the two weak phases can be
chosen completely at will, and we study the behavior of the decay amplitudes
under changes in the two weak phases chosen as a basis. Of course, physical
observables cannot depend on such reparametrizations. This has an impact in
discussions of the SM and in attempts to parametrize new physics effects in the
decay amplitudes. We illustrate these issues by looking at B --> psi K_S and
the isospin analysis in B --> pi pi.Comment: 16 pages, RevTe
Nitrogen use of a mixed tree crop plantation with a leguminous cover crop.
Study on two associated frut tree crops take up their N in comparison to a leguminous cover crop in an agroforestry system. Preliminar results showed the pueraria had the highest foliar N content followed by pupunha; cupuacu having less than the other two. One year after application, cupuacu took up more of the applied N in comparison to the total N uptake than pueraria and pupunha as seen from the high &15N values. The amount of 15N taken up in relation to dry matter equaled between the three species, since pueraria had a lot higher N contents. The other sampling dates showed the same tendency.bitstream/item/181065/1/ID-2600-2-45-52.pd
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