2,785 research outputs found

### Huge right-handed current effects in B->K*(K pi)l+l- in supersymmetry

Transverse asymmetries in the decay B->K*(K pi)l+l- are an extremely
sensitive probe of right-handed flavour-changing neutral currents. We show how
to include the contribution from the chiral partner of the electromagnetic
operator on the transverse asymmetries at NLO in QCD factorization. We then
consider supersymmetric models with non-minimal flavour violation in the
down-squark sector. We include all the relevant experimental constraints and
present a numerical formula for B->Xs gamma that takes into account the most
recent NNLO calculations. We show that the flavour-changing parameters of these
models are poorly constrained by present data and allow for large effects on
the transverse asymmetries that we consider.Comment: 12 pages, 4 figures, version to appear on JHE

### Extended Minimal Flavour Violating MSSM and Implications for B Physics

The recently reported measurements of the CP asymmetry a(psi K) by the BABAR
and BELLE collaborations are in good agreement with the standard model (SM)
prediction, resulting from the unitarity of the CKM matrix. The so-called
minimal flavour violating (MFV) supersymmetric extensions of the standard
model, in which the CKM matrix remains the only flavour changing structure,
predict a(psi K) similar to the one in the SM. With the anticipated precision
in a(psi K) and other CP asymmetries at the B factories and hadron colliders,
one hopes to pin down any possible deviation from the SM. We discuss an
extension of the MFV-supersymmetric models which comfortably accommodates the
current measurements of the CP asymmetry a(psi K), but differs from the SM and
the MFV-supersymmetric models due to an additional flavour changing structure
beyond the CKM matrix. We suggest specific tests in forthcoming experiments in
B physics. In addition to the CP-asymmetries in B-meson decays, such as a(psi
K) and a(pi pi), and the mass difference Delta M_s in the Bs-bar(Bs) system, we
emphasize measurements of the radiative transition b -> d gamma as sensitive
probes of the postulated flavour changing structure. Interestingly, the
CKM-unitarity analysis in the Extended-MFV model also allows solutions rho < 0,
as opposed to the SM and the MFV models for which only rho > 0 solutions are
now admissible, implying gamma > pi/2, where gamma=- arg (Vub). Such large
values of gamma are hinted by the current measurements of the branching ratios
for the decays B -> pi pi and B -> K pi.Comment: 35 pages, 12 figures. Theoretical analysis modified in view of the
recent CP violation observed in B-> J/Psi K decays. Resulting constraints on
the model parameters are recompute

### Demise of CKM & its aftermath

Using firmly established experimental inputs such as epsilon_K, Delta M_d,
Delta M_s, BR(B -> tau nu), gamma, V_cb along with corresponding lattice matrix
elements which have been well studied and are in full QCD such as B_K, SU3
breaking ratio xi, B_Bs and in particular without using V_ub or the
pseudoscalar decay constants f_Bd or f_Bs from the latice, we show that the
CKM-paradigm now appears to be in serious conflict with the data. Specifically
the SM predicted value of sin(2 beta) seems too high compared to direct
experimental measured value by over 3 sigma. Furthermore, our studiy shows that
new physics predominantly effects B-mixings and B_d -> psi K_s, and not
primarily in kaon-mixing or in B -> tau nu. Model independent operator analysis
suggests the scale of underlying new physics, accompanied by a BSM CP-odd
phase, responsible for breaking of the SM is less than a few TeV, possibly as
low as a few hundred GeV. Two possible BSM scenarios, namely warped
extra-dimensions and SM with a 4th generation, are briefly discussed. Generic
predictions of warped flavor models are briefly discussed. While SM with 4th
generation (SM4) is a very simple way to account for the observed anomalies,
SM4 is also well motivated due to its potential role in dynamical electrweak
symmetery breaking via condensation of heavy quarks and in barygenesis.Comment: 18 pages, 8 figures, talk given at Moriond EW 2011, corrected typos
in Fig.6 label

### Contributions of flavor violating couplings of a Higgs boson to $pp\to WW$

We study contributions to $pp\to W^+W^- \to \ell\nu_\ell
\ell^\prime\nu_{\ell^\prime}$ in models with a new Higgs boson, $H$, and a
neutral lepton, $\nu_{4}$, with couplings $H-\nu_{4}-\nu_{\mu}$ and
$W-\nu_{4}-\mu$ through the process $pp \to H \to \nu_4 \nu_\mu \to W \mu
\nu_\mu \to \ell\nu_\ell \mu \nu_\mu$. Contrary to naive expectations, we find
that contributions to $pp\to WW$ can be very large while satisfying constraints
from standard $H\to WW$ and $H\to\gamma\gamma$ searches. Even the excess
observed by ATLAS in $pp\to WW$, if taken at face value, can be easily
accommodated. The various kinematic distributions fit nicely the experimentally
determined ones. This scenario can arise for example in a two Higgs doublet
model with vectorlike leptons.Comment: 16 pages, 5 figure

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