2,681 research outputs found
On -functions with bounded spectrum
We consider the class of functions in ,
whose Fourier transform has bounded support. We obtain a description of
continuous maps such that
for every function .
Only injective affine maps have this property
Analysis of the semileptonic transition in topcolor-assisted technicolor (TC2) model
We comparatively analyze the flavor changing neutral current process of the
in the standard model as well as
topcolor-assisted technicolor model using the form factors calculated via light
cone QCD sum rules in full theory. In particular, we calculate the decay width,
branching ratio and lepton forward-backward asymmetry related to this decay
channel. We compare the results of the topcolor-assisted technicolor model with
those of the standard model and debate how the results of the topcolor-assisted
technicolor model depart from the standard model predictions. We also compare
our results on the differential branching ratio with recent experimental data
provided by CDF and LHCb Collaborations.Comment: 29 Pages, 16 Figures and 8 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
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
meson and its structure.Comment: 32 Pages, 8 Figures and 6 Table
Masses and decay constants of bound states containing fourth family quarks from QCD sum rules
The heavy fourth generation of quarks that have sufficiently small mixing
with the three known SM families form hadrons. In the present work, we
calculate the masses and decay constants of mesons containing either both
quarks from the fourth generation or one from fourth family and the other from
known third family SM quarks in the framework of the QCD sum rules. In the
calculations, we take into account two gluon condensate diagrams as
nonperturbative contributions. The obtained results reduce to the known masses
and decay constants of the and quarkonia when the fourth
family quark is replaced by the bottom or charm quark.Comment: 15 Pages, 9 Figures and 6 Table
The cranking formula and the spurious behaviour of the mass parameters
We discuss some aspects of the approach of the mass parameters by means of
the simple cranking model. In particular, it is well known that the numerical
application of this formula is often subject to ambiguities or contradictions.
It is found that these problems are induced by the presence of two derivatives
in the formula. To overcome these problems, we state a useful ansatz and we
develop a number of simple arguments which tend to justify the removal of these
terms. As soon as this is done, the formula becomes simpler and easier to
interpret. In this respect, it is shown how the shell effects affect the mass
parameters. A number of numerical tests help us in our conclusions.Comment: version 3 corrigendum of the ansatz of section V, corrigendum of the
legend of Fig3. Submission = text file + 5 figure
Investigation on the functionality of thermoresponsive origami structures
Additive manufacturing (AM) has recently been introduced as a reliable technique for the fabrication of highly complex geometries that were not possible before. Due to the flexibility in the organization of material properties such as responsive elements in space, AM is now a capable technology for the production of smart structures that can transform their geometry, for example, from a compact state to a deployed configuration. Among others, fused deposition modeling (FDM) can reliably be used to manufacture polymeric constructs with high resolution. Polylactide (PLA), the most popular polymer in FDM printing is a shape-memory polymer. Therefore, the manufacturing of shape-transforming constructs can be simplified to the construction of foldable products that can be programmed simply by applying mechanical forces. Origami can then be used as a simple platform in which the shape-transforming of a programmed construct is via the folding of material through the thinner sections (hinges). Herein, PLA and FDM are used to fabricate foldable structures. The effects of different parameters namely total thickness, layer height, nozzle temperature, and activation temperature on the shape recovery of the manually programmed origami structures are then investigated
Strong coupling constants of bottom and charmed mesons with scalar, pseudoscalar and axial vector kaons
The strong coupling constants, , ,
, , and
, where , and are scalar, pseudoscalar
and axial vector kaon mesons, respectively are calculated in the framework of
three-point QCD sum rules. In particular, the correlation functions of the
considered vertices when both and mesons are off-shell
are evaluated. In the case of , which is either or
, the mixing between these two states are also taken into account. A
comparison of the obtained result with the existing prediction on
as the only coupling constant among the considered
vertices, previously calculated in the literature, is also made.Comment: 20 Pages, 3 Figures and 8 Table
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