3,680 research outputs found
Identification of placental transforming growth factor-beta and bikunin metabolites as contaminants of pharmaceutical human chorionic gonadotrophin preparations by proteomic techniques
This paper is the first to identify the novel bio-molecules found in pregnancy urine and commonly contaminate clinical grade hCG preparation extracted from urine reported to have anti-HIV/HIV Kaposis . Professor Iles was the Principal Investigator
Long-range two-body final-state interactions and direct CP asymmetry in {B}^{+}\to{\pi}^{+} {K}^{0} decay
We present a calculation of the direct CP asymmetry, , for the
process including the effects of long-range inelastic
final-state interactions (FSI). We admit three channels in our calculation:
, and . The strong
scattering is described in terms of Pomeron and Regge exchanges. We find that
the direct CP asymmetry is enhanced by a factor of as a result of FSI,
but remains well short of the claims of (10 - 20)% in recent literature. A
critical assessment of papers claiming large CP asymmetries is also presented.Comment: 21 pages, latex, no figures. Added the charge-exchange channel
{B}^{+}\to {\pi}^{0} {K}^{+}. Expanded the discussion section. To be
published in Phys. Rev.
Extraction of from the Decay
We develop the perturbative QCD formalism including Sudakov effects for
semi-leptonic meson decays. We evaluate the differential decay rate of
, and find that the perturbative calculation is reliable for
the energy fraction of the pion above 0.3. Combining predictions from the soft
pion theorems, we extract the value of the matrix element which is
roughly .Comment: 10 pages, CCUTH-94-05, IP-ASTP-13-9
The decay constants of pseudoscalar mesons in a relativistic quark model
The decay constants of pseudoscalar mesons are calculated in a relativistic
quark model which assumes that mesons are made of a valence quark antiquark
pair and of an effective vacuum like component. The results are given in terms
of quark masses and of some free parameters entering the expression of the
internal wave functions of the mesons. By using the pion and kaon decay
constants to fix the parameters of the
model one gets for the light quark masses
and the heavy quark masses in the
range: . In the case of
light neutral mesons one obtains with the same set of parameters
. The
values are in agreement with the experimental data and other theoretical
results.Comment: 11 pages, LaTe
Bc Meson Formfactors and Bc-->PV Decays Involving Flavor Dependence of Transverse Quark Momentum
We present a detailed analysis of the Bc form factors in the BSW framework,
by investigating the effects of the flavor dependence on the average transverse
quark momentum inside a meson. Branching ratios of two body decays of Bc meson
to pseudoscalar and vector mesons are predicted.Comment: 18 pages, 5 figure
High-resolution x-ray study of the nematic - smectic-A and smectic-A - smectic-C transitions in 8barS5-aerosil gels
The effects of dispersed aerosil nanoparticles on two of the phase
transitions of the thermotropic liquid crystal material
4-n-pentylphenylthiol-4'-n-octyloxybenzoate 8barS5 have been studied using
high-resolution x-ray diffraction techniques. The aerosils hydrogen bond
together to form a gel which imposes a weak quenched disorder on the liquid
crystal. The smectic-A fluctuations are well characterized by a two-component
line shape representing thermal and random-field contributions. An elaboration
on this line shape is required to describe the fluctuations in the smectic-C
phase; specifically the effect of the tilt on the wave-vector dependence of the
thermal fluctuations must be explicitly taken into account. Both the magnitude
and the temperature dependence of the smectic-C tilt order parameter are
observed to be unaffected by the disorder. This may be a consequence of the
large bare smectic correlation length in the direction of modulation for this
transition. These results show that the understanding developed for the nematic
to smectic-A transition for octylcyanobiphenyl (8CB) and octyloxycyanobiphenyl
(8OCB) liquid crystals with quenched disorder can be extended to quite
different materials and transitions.Comment: 7 pages, 8 figure
The , , and decays in the perturbative QCD approach
Two-body non-leptonic charmed decays , ,
and are analyzed in perturbative QCD approach, where
and denote the light pseudoscalar meson and vector meson, respectively.
We test the meson wave function by a fit with experimental data of
six channels. We give the branching ratios of all the charmed B decay
channels, most of which agree with experiments amazingly well. The predicted
decays can be confronted with the future experimental data. By
straightforward calculations, our pQCD approach gives the right relative strong
phase of with experiments. We also predict the percentage of
transverse polarizations in decay channels.Comment: 25 pages, 4 figure
Applicability of Perturbative QCD to Decays
We examine the applicability of perturbative QCD to meson decays into
mesons. We find that the perturbative QCD formalism, which includes Sudakov
effects at intermediate energy scales, is applicable to the semi-leptonic decay
, when the meson recoils fast. Following this conclusion, we
analyze the two-body non-leptonic decays and . By
comparing our predictions with experimental data, we extract the matrix element
.Comment: 18 pages in Latex, figures are available upon reques
Quark Mass Hierarchies, Flavor Mixing and Maximal CP-Violation
Flavor mixing and the quark mass spectrum are intimately related. In view of
the observed strong hierarchy of the quark and lepton masses and of the flavor
mixing angles it is argued that the description of flavor mixing must take this
into account. One particular interesting way to describe the flavor mixing
emerges, which is particularly suited for models of quark mass matrices based
on flavor symmetries. We conclude that the unitarity triangle important for
physics should be close to or identical to a rectangular triangle.
violation is maximal in this sense.Comment: 21 latex page
- …