Impact of additional bosons on the exploration of the Higgs boson at the LHC

The LHC is making strides in the exploration of the properties of the newly discovered Higgs boson, [Formula: see text]. In Refs. 7–9 the compatibility of the proton–proton data reported in the Run I period with the presence of a heavy scalar, [Formula: see text], with a mass around 270 GeV and its implications were explored. This boson would decay predominantly to [Formula: see text], where [Formula: see text], is a lighter scalar boson. The production cross-section of [Formula: see text] is considerable and it would significantly affect the inclusive rate of [Formula: see text]. The contamination from this new production mechanism would depend strongly on the final state used to measure the rate of [Formula: see text]. The contamination in the rate measurement of [Formula: see text], [Formula: see text], [Formula: see text] is estimated to be small. This statement does not depend strongly on assumptions made on the decay of [Formula: see text]. The impact on other channels related to the search of Vector Boson Fusion and [Formula: see text] production with the diphoton decay is evaluated, where the dependence on assumption on the decay of [Formula: see text] is expected to be significant.

FCNC DECAYS OF B MESONS

The paper reviews recent results from the Belle experiment on the flavor changing neutral current processes b→sγ, b→dγ and b→sℓ+ℓ-. We report on a new measurement of the b→sγ inclusive rate and of the moments of the photon energy distribution. We also present the measurements of rate, isospin asymmetry and CP violation in the B→K*γ decays, as well as the CP asymmetry measurement in the inclusive B→Xsγ transitions. We report on the evidence for exclusive b→dγ transitions, and finally present the first observation of the B→K*ℓ+ℓ- decay and updated measurements of the B→Kℓ+ℓ- and B→Xsℓ+ℓ- branching fractions.

EXACT NONFACTORIZABLE ${\mathcal O}(\alpha_sg^2)$ TWO-LOOP CONTRIBUTION TO $Z\to b\bar b$

For [Formula: see text], we calculate all the two-loop top-dependent Feynman graphs, which have mixed QCD and electroweak contributions that are not factorizable. To evaluate the graphs, without resorting to a mass expansion, we apply a two-loop extension of the one-loop Passarino–Veltman reduction. This is an analytic-numerical method, which first converts all diagrams into a set of ten standard scalar functions, and then integrates them numerically over the remaining Feynman parameters, with rapid convergence and high accuracy. We discuss the treatment of ir singularities within our methods. We do not resort to unitarity cuts of two-point functions for calculating decay rates; these are useful only to obtain an inclusive rate. For this reason, experimental cuts and the experimental ir energy resolution can be implemented in our calculation, once the corresponding one-loop gluon bremsstrahlung process is added to this calculation.

Bound on V+A Admixture in the b→c Current from Inclusive vs Exclusive Semileptonic Decays of B Mesons

An admixture of a right-handed b→ c current in the semileptonic weak decays of the B mesons would give a significantly different contribution to the inclusive rate of the decays B→lν Xc as compared to the exclusive decay B→ D* lν at zero recoil. Thus a difference in the values of |Vcb| extracted from the data on these two types of decay would measure such admixture. The present marginal mismatch in determination of |Vcb| by the two methods can be interpreted as corresponding to gR/gL≈ 0.14±0.18.