224 research outputs found

### The Radiative rare decays $B\to K^{**}\gamma$ in the light-cone QCD sum rule approach

We predict contributions of higher $K$-resonances to the radiative rare
decays $b\to s\gamma$, in the framework of the QCD sum rules on the light cone,
which combines the traditional QCD sum rule method with the description of
final state mesons in terms of the light-cone wave functions of increasing
twist. Our calculations are restricted to the leading twist-two operators for
$K^*(892)$ and to the asymptotic wave function for the other $K^{**}$-mesons.
Using experimental data on the semileptonic $\tau\to K^{**}\nu_{\tau}$
decays, we extract the corresponding decay constants for vector and
axial-vector $K^{**}$-mesons. Based on our estimate of the transition form
factor $F_1^{K^*(892)}(0)=0.32 \pm 0.06$ and the $K_2^*(1430)$ decay constant
$f_{K_2^*(1430)}=(160\pm 20) MeV$, we find good agreement with experimental
results. The two largest fractions of the inclusive $b\to s\gamma$ branching
ratio are found to be $(10.0\pm 4.0)%$ for $B\to K^*(892) \gamma$ and $(5.0\pm
2.0)%$ for $B\to K_2^*(1430)\gamma$ decays. We also compare our results with
the existing theoretical predictions.Comment: 29 pages, 20 figures, to be submitted to European Physical Journal

### Analysis of the $B \to K^*_2(1430), a_2(1320), f_2(1270)$ form-factors with light-cone QCD sum rules

In this article, we study the $B \to K^*_2(1430)$, $a_2(1320)$, $f_2(1270)$
form-factors with the light-cone QCD sum rules, where the $B$-meson light-cone
distribution amplitudes are used. In calculations, we observe that the
line-shapes of the $B$-meson light-cone distribution amplitude $\phi_+(\omega)$
have significant impacts on the values of the form-factors, and expect to
obtain severe constraints on the parameters of the $B$-meson light-cone
distribution amplitudes from the experimental data in the future.Comment: 19 pages, 6 figures, slight revisio

### Branching Ratio and CP-asymmetry for B-> 1^{1}P_{1}gamma decays

We calculate the branching ratios for B_{d}^{0}->(b_{1},h_{1})gamma at
next-to-leading order (NLO) of alpha_{s} where b_{1} and h_{1} are the
corresponding radially excited axial vector mesons of rho and omega
respectively. Using the SU(3)symmetry for the form factor, the branching ratio
for B_{d}^{0}->(b_{1},h_{1})gamma is expressed in terms of the branching ratio
of the B_{d}^{0}-> K_{1}gamma and it is found to be
B(B_{d}^{0}->b_{1}gamma)=0.71* 10^{-6} and B(B_{d}^{0}-> h_{1}gamma)
=0.74*10^{-6}. We also calculate direct CP asymmetry for these decays and find,
in confirmity with the observations made in the literature, that the hard
spectator contributions significantely reduces the asymmetry arising from the
vertex corrections alone. The value of CP-asymmetry is 10% and is negative like
rho and omega in the Standard Model.Comment: 10 pages, 2 figure

### Phenomenological discussion of $B\to P V$ decays in QCD improved factorization approach

Trying a global fit of the experimental branching ratios and CP-asymmetries
of the charmless $B\to PV$ decays according to QCD factorization, we find it
impossible to reach a satisfactory agreement, the confidence level (CL) of the
best fit is smaller than .1 %. This failure reflects the difficulty to
accommodate several large experimental branching ratios of the strange
channels. Furthermore, experiment was not able to exclude a large direct CP
asymmetry in $\bar {B}^0\to\rho^+ \pi^-$, which is predicted very small by QCD
factorization. Proposing a fit with QCD factorization 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: 8 pages, 2 figures (requires epsfig, psfrag),talk presented at the
XXXVIIIth Rencontres de Moriond: Electroweak Interactions and Unified
Theories,Les Arcs, France, March 15-22, 2003. To be published in the
Proceeding

### Use of ERTS data for a multidisciplinary analysis of Michigan resources

There are no author-identified significant results in this report

### CP Violation in B -> pi+ pi- and the Unitarity Triangle

We analyze the extraction of weak phases from CP violation in
$B\to\pi^+\pi^-$ decays. We propose to determine the unitarity triangle
$(\bar\rho,\bar\eta)$ by combining the information on mixing induced CP
violation in $B\to\pi^+\pi^-$, $S$, with the precision observable $\sin 2\beta$
obtained from the CP asymmetry in $B\to\psi K_S$. It is then possible to write
down exact analytical expressions for $\bar\rho$ and $\bar\eta$ as simple
functions of the observables $S$ and $\sin 2\beta$, and of the penguin
parameters $r$ and $\phi$. As an application clean lower bounds on $\bar\eta$
and $1-\bar\rho$ can be derived as functions of $S$ and $\sin 2\beta$,
essentially without hadronic uncertainty. Computing $r$ and $\phi$ within QCD
factorization yields precise determinations of $\bar\rho$ and $\bar\eta$ since
the dependence on $r$ and $\phi$ is rather weak. It is emphasized that the
sensitivity to the phase $\phi$ enters only at second order and is extremely
small for moderate values of this phase, predicted in the heavy-quark limit.
Transparent analytical formulas are further given and discussed for the
parameter $C$ of direct CP violation in $B\to\pi^+\pi^-$. We also discuss
alternative ways to analyze $S$ and $C$ that can be useful if new physics
affects $B_d$--$\bar B_d$ mixing. Predictions and uncertainties for $r$ and
$\phi$ in QCD factorization are examined in detail. It is pointed out that a
simultaneous expansion in $1/m_b$ and 1/N leads to interesting simplifications.
At first order infrared divergences are absent, while the most important
effects are retained. Independent experimental tests of the factorization
framework are briefly discussed.Comment: 26 pages, 7 figure

### Implications of the first observation of $B\to K_1\gamma$

Implications of the recent new measurements of $B\to K_1\gamma$ by Belle are
examined. It is shown that the new branching ratio \calB(B\to
K_1(1270)\gamma) requires very large form factor compared to the theoretically
predicted one. This is an opposite case to $B\to K^*\gamma$ where theory
expected larger branching ratio. Possible origins of the discrepancy are
discussed.Comment: 4 pages, 3 figure

### Exclusive B-meson Rare Decays and General Relations of Form Factors in Effective Field Theory of Heavy Quarks

B meson rare decays ($B\to K(K^{*})l\bar l$ and $B\to K^*\gamma$) 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 $1/m_Q$
expansion. Four exact relations between the two types of form factors are
obtained at the leading order of $1/m_Q$ 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

### Bd^0(t)->pi^+pi^- and Bs^0(t)-> K^+ K^- Decays: A Tool to Measure New-Physics Parameters

If physics beyond the standard model is present in B decays, experimental
measurements seem to suggest that it principally affects those processes with
significant b->s penguin amplitudes. It was recently argued that, in general,
such new-physics (NP) effects can be parametrized in terms of a single NP
amplitude A^q and phase \Phi_q, for q=u,d,s,c. In this paper, we show that the
study of the decays Bs(t) -> K^+ K^- and Bd(t) -> \pi^+\pi^- allows one to
measure the NP parameters A^u and \Phi_u. We examine the implications for this
method of the latest experimental results on these decays. If NP is found in
Bs(t) -> K^+ K^-, it can be partially identified through measurements of
Bs(t)-> K^0 \bar K^0.Comment: 12 pages, 2 figures, LaTeX. Changed reference

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