On L2L^2 -functions with bounded spectrum

We consider the class $PW(\mathbb R^n)$ of functions in $L^2(\mathbb R^n)$, whose Fourier transform has bounded support. We obtain a description of continuous maps $\varphi : \mathbb R^m\rightarrow\mathbb R^n$ such that $f\circ\varphi\in PW(\mathbb R^m)$ for every function $f\in PW(\mathbb R^n)$. Only injective affine maps $\varphi$ have this property

Modelling moment redistribution in continuous reinforced concrete beams.

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN011126 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Rare Radiative Bc→Ds1(2460)γB_{c}\rightarrow D_{s1}(2460)\gamma Transition in QCD

We investigate the radiative $B_{c} \to D_{s1} \gamma$ transition in the framework of QCD sum rules. In particular, we calculate the transition form factors responsible for this decay in both weak annihilation and electromagnetic penguin channels using the quark condensate, mixed and two-gluon condensate diagrams as well as propagation of the soft quark in the electromagnetic field as non-perturbative corrections. These form factors are then used to estimate the branching ratios of the channels under consideration. The total branching ratio of the $B_{c} \to D_{s1} \gamma$ transition is obtained to be in order of $10^{-5}$, and the dominant contribution comes from the weak annihilation channel.Comment: 24 Pages and 3 Figure

Semileptonic Dq→K1ℓνD_{q}\to K_{1}\ell \nu and nonleptonic D→K1πD\to K_1 \pi decays in three--point QCD sum rules and factorization approach

We analyze the semileptonic $D_{q}\to K_1 \ell\nu$ transition with $q=u, d, s$, in the framework of the three--point QCD sum rules and the nonleptonic $D\to K_1 \pi$ decay within the QCD factorization approach. We study $D_{q}$ to $K_1(1270)$ and $K_1(1400)$ transition form factors by separating the mixture of the $K_1(1270)$ and $K_1(1400)$ states. Using the transition form factors of the $D\to K_1$, we analyze the nonleptonic $D\to K_1 \pi$ decay. We also present the decay amplitude and decay width of these decays in terms of the transition form factors. The branching ratios of these channel modes are also calculated at different values of the mixing angle $\theta_{K_1}$ and compared with the existing experimental data for the nonleptonic case.Comment: 28 Pages, 20 Figures and 9 Table

Analysis of the rare semileptonic B_c \rar P(D,D_s) l^{+}l^{-}/\nu\bar{\nu} decays within QCD sum rules

Considering the gluon condensate corrections, the form factors relevant to the semileptonic rare B_c \rar D,D_s(J^{P}=0^{-}) l^{+}l^{-} with $l=\tau,\mu,e$ and B_c \rar D,D_s(J^{P}=0^{-})\nu\bar{\nu} transitions are calculated in the framework of the three point QCD sum rules. The heavy quark effective theory limit of the form factors are computed. The branching fraction of these decays are also evaluated and compared with the predictions of the relativistic constituent quark model. Analyzing of such type transitions could give useful information about the strong interactions inside the pseudoscalar $D_{s}$ meson and its structure.Comment: 32 Pages, 8 Figures and 6 Table