953 research outputs found
Hunting the CKM weak phase with time-integrated Dalitz analyses of Bs -> K pi pi decays
We present a new technique to extract information on the Unitarity Triangle
from the study of Bs -> K pi pi Dalitz plot. Using isospin symmetry and the
possibility to access the decay amplitudes from Dalitz analyses, we propose a
new strategy to extract the weak phase gamma from Bs to K pi pi.Comment: 2 pages. v2: Discussion of interference on Dalitz plot clarified. Bs
-> K K pi channels removed. v3: Improved discussion of experimental aspects.
Final version to appear in Phys. Lett.
CP violation in supersymmetric theories
We review the present status of CP violating problem in supersymmetric
extensions of the standard model. We analyze the constraints imposed by the
experimental limits of the electron, neutron, and mercury electric dipole
moments on the supersymmetric CP phases and show that only the scenarios with
flavour-off- diagonal CP violation remain attractive. These scenarios require
hermitian Yukawa matrices which naturally arise in models with left-right
symmetry or a SU(3) flavour symmetry. In this case, epsilon_K and
epsilon'/epsilon can be saturated by a small non-universality of the soft
scalar masses through the gluino and chargino contributions respectively. The
model also predicts a strong correlation between A_{CP}(b-> s gamma) and the
neutron electric dipole moment. In this framework, the standard model gives a
the leading contribution to the CP asymmetry in B ->psi K_S decay, while the
dominant chargino contribution to this asymmetry is < 0.2. Thus, no constraint
is set on the non-universality of this model by the recent BaBar and Belle
measureets.Comment: 34 pages, 10 figures. Invited review article for International
Journal of Modern Physics
Status of the CKM matrix
An updated determination of the parameters of the Cabibbo-Kobayashi-Maskawa
matrix is presented.Comment: 8 pages, 9 figures, uses espcrc2.sty. Talk given at the "7th Topical
Seminar on the Legacy of LEP and SLC", 8-11 October 2001, Siena (Italy
The CKM matrix and CP Violation
The status of CP violation and the CKM matrix is reviewed. Direct CP
violation in B decay has been established and the measurement of sin(2beta) in
\psi K modes reached 5% accuracy. I discuss the implications of these, and of
the possible deviations of the CP asymmetries in b->s modes from that in \psi
K. The first meaningful measurements of alpha and gamma are explained, together
with their significance for constraining both the SM and new physics in B-Bbar
mixing. I also discuss implications of recent developments in the theory of
nonleptonic decays for B->pi K rates and CP asymmetries, and for the
polarization in charmless B decays to two vector mesons.Comment: Plenary talk at 32nd International Conference on High Energy Physics
(ICHEP'04), August 16-22, 2004, Beijing, China. v2: Table 5 corrected, minor
changes in some averages (updated to hfag, that include correlations between
S and C). v3: Figure 8 fixed, minor final change
B_s to K^(*)0 \bar K^(*)0 decays: the golden channels for new physics searches
We point out that time-dependent CP asymmetries in B_s to K^{*0} \bar K^{*0}
decays probe the presence of new physics in b to s transitions with an
unprecedented theoretical accuracy. We show that, contrary to the case of B_d
to phi K_S, it is possible to obtain a model-independent prediction for the
coefficient S(B_s to K^{*0} \bar K^{*0}) in the Standard Model. We give an
estimate of the experimental precision achievable with the next generation of B
physics experiments. We also discuss how this approach can be extended to the
case of B_s to \bar K^{*0} K^0, B_s to K^{*0} \bar K^0 and B_s to K^0 \bar K^0
decays and the different experimental challenges for these channels.Comment: 4 pages, 1 figure. v2: Corrected dependence on CKM angles, expanded
discussion of multiple polarizations, conclusions strengthened. Final version
to appear in PR
The Chromomagnetic Dipole Operator and the B Semileptonic Branching Ratio
We consider the possibility of having a large branching ratio for the decay
coming from an enhanced Wilson coefficient of the chromomagnetic
dipole operator. We show that values of up to or
more are compatible with the constraints coming from the CLEO experimental
results on and . Such large values can
reconcile the predictions of both the semileptonic branching ratio and the
charm counting with the present experimental results. We also discuss a
supersymmetric model with gluino-mediated flavour violations, which can account
for such large values of .Comment: 19 pages, 3 eps figures included, replacement with minor change
b -> s Transitions: A New Frontier for Indirect SUSY Searches
The present unitarity triangle fit, whose essential input is represented by
the s to d and b to d transition processes, fully agrees with the SM. However,
most of the phenomena involving b to s transitions are still largely unexplored
and hence b to s phenomenology still constitutes a place for new physics
manifestations, in spite of the tremendous experimental and theoretical
progress on B to X_s gamma. We perform a systematic study of the CP conserving
and violating SUSY contributions to b to s processes in a generic MSSM. We
consider gluino exchange contributions including NLO QCD corrections and
lattice hadronic matrix elements for Delta B = 2 and Delta B = 1 processes. We
take into account all available experimental information on processes involving
b to s transitions (B to X_s gamma, B to X_s l^+ l^- and the lower bound on the
B_s - bar B_s mass difference Delta M_s). We study the correlations among the
relevant observables under scrutiny at present or in a not too far future:
Delta M_s and the amount of CP violation in B to phi K_s, B_s to J/psi phi, B
to X_s gamma. In particular we discuss the recent data by BaBar and BELLE on
the time-dependent CP asymmetry in the decay B to phi K_s which suggest a
deviation from the SM expectation. Our results show that the processes
involving b to s transitions represent a splendid opportunity to constrain
different MSSM realizations, and, even more important, that they offer concrete
prospects to exhibit SUSY signals at B factories and hadron colliders in spite
of all the past frustration in FCNC searches of new physics hints.Comment: 20 pages, 8 figures. Bug in the code corrected, figures for RL and
RL=RR cases and some conclusions change
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