205 research outputs found
Exclusive B-meson Rare Decays and General Relations of Form Factors in Effective Field Theory of Heavy Quarks
B meson rare decays ( and ) are
analyzed in the framework of effective field theory of heavy quarks. The
semileptonic and penguin type form factors for these decays are calculated by
using the light cone sum rules method at the leading order of
expansion. Four exact relations between the two types of form factors are
obtained at the leading order of expansion. Of particular, the
relations are found to hold for whole momentum transfer region. We also
investigate the validity of the relations resulted from the large energy
effective theory based on the general relations obtained in the present
approach. The branching ratios of the rare decays are presented and their
potential importance for extracting the CKM matrix elements and probing new
physics is emphasized.Comment: 23 pages, Revtex, 32 figures, published version with the errors of
numerical results caused by the computer program are correcte
Primary solitary retro-clival amyloidoma.
Amyloidosis encompasses a group of disorders sharing the common feature of intercellular deposition of amyloid protein by several different pathogenetic mechanisms. Primary solitary amyloidosis, or amyloidoma, is a rare subset of amyloidosis in which amyloid deposition is focal and not secondary to a systemic process or plasma cell dyscrasia.This 84-year-old female presented with history of multiple syncopal episodes, dysphagia, and ataxia. Motor strength was 3+/5 in the right upper extremity. Rheumatoid factor, cyclic citrullinated peptide (CCP), and anti-nuclear antibody (ANA) were normal. Serum and urine immune-electrophoresis detected no abnormal bands. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated a non-enhancing soft-tissue mass extending from the retro-clivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction. Endoscopic trans-nasal debulking of the retro-clival mass was performed with occiput to C5 posterior instrumentation for spinal stabilization.Primary solitary amyloidosis, unlike other forms of amyloidosis, has an excellent prognosis with local resection. Diagnosis requires special stains and a degree of suspicion for the disease. This is the first report to document an endoscopic trans-nasal approach for removal of a primary solitary amyloidosis of the retro-clivus. Management of vertebral amyloidoma involves aggressive local resection of the tumor when feasible and spine stabilization as the degree of tumor involvement mandates. Complete evaluation for the diagnosis of systemic amyloidosis is essential for the management and prognostication. Surgeons encountering such lesions must maintain high suspicion for this rare disease and advise pathologists accordingly to establish the correct diagnosis
Radiative B decays to the axial mesons at next-to-leading order
We calculate the branching ratios of at next-to-leading
order (NLO) of where is the orbitally excited axial vector
meson. The NLO decay amplitude is divided into the vertex correction and the
hard spectator interaction part. The one is proportional to the weak form
factor of transition while the other is a convolution between
light-cone distribution amplitudes and hard scattering kernel. Using the
light-cone sum rule results for the form factor, we have \calB(B^0\to
K_1^0(1270)\gamma)=(0.828\pm0.335)\times 10^{-5} and \calB(B^0\to
K_1^0(1400)\gamma)=(0.393\pm0.151)\times 10^{-5}.Comment: 17pages, 4 figures. Minor changes, typos corrected. PRD accepted
versio
Forward-backward and isospin asymmetry for B -> K* l+ l- decay in the standard model and in supersymmetry
We discuss two dedicated observables in exclusive B -> K* l+ l- decay that
can be used to study effects of physics beyond the standard model, namely the
forward-backward asymmetry in the lepton spectrum and the isospin-asymmetry
between decays of charged and neutral B mesons. We consider the region of large
recoil-energy (i.e. small invariant mass of the lepton pair), and employ the
QCD factorization approach to exclusive B meson decays. Sub-leading effects in
the heavy quark mass expansion have been taken into account for the calculation
of the isospin-asymmetry. We give predictions for decay asymmetries in the
standard model, and its supersymmetric extension with minimal flavor violation,
using parameter values allowed by current experimental constraints on B->X_s
gamma decay.Comment: 21 pages, LaTeX with 6 figures, added reference
Photon polarization in radiative B decays
We study decay distributions in B -> K pi pi gamma, combining contributions
from several overlapping resonances in a K pi pi mass range near 1400 MeV,
(1^+) K_1(1400), (2^+) K^*_2(1430) and (1^-) K^*(1410). A method is proposed
for using these distributions to determine a photon polarization parameter in
the effective radiative weak Hamiltonian. This parameter is measured through an
up-down asymmetry of the photon direction relative to the K pi pi decay plane.
We calculate a dominant up-down asymmetry of 0.33 +- 0.05 from the K1(1400)
resonance, which can be measured with about 10^8 B B-bar pairs, thus providing
a new test for the Standard Model and a probe for some of its extensions.Comment: 22 pages, 3 figures, version to appear in Phys. Rev.
Testing QCD factorisation and charming penguins in charmless
We try a global fit of the experimental branching ratios and CP-asymmetries
of the charmless decays according to QCD factorisation. We find it
impossible to reach a satisfactory agreement, the confidence level (CL) of the
best fit is smaller than .1 %.
The main reason for this failure is the difficulty to accomodate several
large experimental branching ratios of the strange channels. Furthermore,
experiment was not able to exclude a large direct CP asymmetry in , which is predicted very small by QCD factorisation.
Trying a fit with QCD factorisation complemented by a charming-penguin inspired
model we reach a best fit which is not excluded by experiment (CL of about 8 %)
but is not fully convincing.
These negative results must be tempered by the remark that some of the
experimental data used are recent and might still evolve significantly.Comment: 21 pages, 4 figures; several typos corrected, added one footnote and
two references, comments added about PQCD. To appear in Phys.Rev.
P and CP violation in B physics
While the Kobayashi--Maskawa single phase origin of CP violation passed its
first crucial precision test in , the chirality of weak
-quark couplings has not yet been carefully tested. We discuss recent
proposals for studying the chiral and CP-violating structure of these couplings
in radiative and in hadronic B decays.Comment: 15 pages, talk at PASCOS'03, Tata Inst., Mumbai, Jan. 200
Direct CP Violation, Branching Ratios and Form Factors , in Decays
The and transitions involved in hadronic B decays are
investigated in a phenomenological way through the framework of QCD
factorization. By comparing our results with experimental branching ratios from
the BELLE, BABAR and CLEO Collaborations for all the B decays including either
a pion or a kaon, we propose boundaries for the transition form factors and depending on the CKM matrix element parameters and
. From this analysis, the form factors required to reproduce the
experimental data for branching ratios are and
. We calculate the direct CP violating asymmetry
parameter, , for and decays, in the case where mixing effects are taken into
account. Based on these results, we find that the direct CP asymmetry for
, ,
, and , reaches its maximum when the invariant mass is
in the vicinity of the meson mass. The inclusion of
mixing provides an opportunity to erase, without ambiguity, the phase
uncertainty mod in the determination of the CKM angles in case
of and in case of .Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two
references adde
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