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The BABAR Collaboration BABAR, the detector for the SLAC PEP-II asymmetric e + e − B Factory operating at the Υ (4S) resonance, was designed to allow comprehensive studies of CP -violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems , VME-and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.

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The muon anomalous magnetic moment a μ and the hadronic vacuum polarization are examined using data analyzed within the framework of a suitably broken HLS model. The analysis relies on all available scan data samples and leaves provisionally aside the existing ISR data. Our HLS model based global fit approach allows for a better check of consistency between data sets and we investigate how results depend on different strategies which may be followed. Relying on global fit qualities, we find several acceptable solutions leading to ambiguities in the reconstructed value for (a μ ) th . Among these, the most conservative solution is a had,LO μ [HLS improved] = 687.72(4.63) × 10 −10 and (a μ ) th = 11 659 175.37(5.31) × 10 −10 corresponding to a 4.1σ significance for the difference a μ = (a μ ) exp − (a μ ) th . It is also shown that the various contributions accessible through the model yield uniformly a factor 2 improvement of their uncertainty. The breaking procedure implemented in the HLS model is an extension of the former procedure based on a mechanism defined by Bando, Kugo and Yamawaki (BKY). This yields a quite satisfactory simultaneous description of most e + e − annihilation channels up to and including the φ meson (and of a set of 10 (mostly radiative) decay widths of light mesons. It also allows to achieve the proof of consistency between the e + e − → π + π − annihilation and the τ ± → π ± π 0 ν decay and gives a solution to the reported problem concerning the measured partial width ratio Γ (φ → K + K − )/Γ (φ → K 0 K 0 ). Prospects for improving the VMD based estimates of a μ are emphasized. a

A global fit of parameters allows us to pin down the Hidden Local Symmetry (HLS) effective Lagrangian, which we apply for the prediction of the leading hadronic vacuum polarization contribution to the muon g − 2. The latter is dominated by the annihilation channel e + e − → π + π − , for which data are available by scan (CMD-2 & SND) and ISR (KLOE-2008, KLOE-2010 experiments. It is well known that the different data sets are not in satisfactory agreement. In fact it is possible to fix the model parameters without using the π + π − data, by using instead the dipion spectra measured in the τ -decays together with experimental spectra for the π 0 γ , ηγ , π + π − π 0 , K + K − , K 0 K 0 final states, supplemented by specific meson decay properties. Among these, the accepted decay width for ρ 0 → e + e − and the partial widths and phase information for the ω/φ → π + π − transitions, are considered. It is then shown that, relying on this global data set, the HLS model, appropriately broken, allows to predict accurately the pion form factor below 1.05 GeV. It is shown that the data samples provided by CMD-2, SND and KLOE-2010 behave consistently with each other and with the other considered data. Consistency problems with the KLOE-2008 and BaBar data samples are substantiated. "All data" global fits are investigated by applying reweighting the conflicting data sets. Constraining to our best fit, the broken HLS model yields a th μ = (11 659 169.55 + +1.26 −0.59 φ + +0.00 −2.00 τ ± 5.21 th ) 10 −10 associated with a very good global fit probability. Correspondingly, we find that a μ = a exp μ − a th μ exhibits a significance ranging between 4.7 and 4.9σ .

Using 116.1 fb(-1) of data collected by the BABAR detector, we present an analysis of xi(c)(0) production in B decays and from the cc continuum, with the xi(c)(0) decaying into omega- K+ and xi- pi+ final states. We measure the ratio of branching fractions B(xi(c)(0) --> omega- K+)/B(xi(c)(0) --> xi- pi+) spectrum is measured on and 40 MeV below the upsilon(4S) resonance. From these spectra the branching fraction product B(B --> xi(c)(0)X) x B(xi(c)(0) --> xi- pi+) is measured to be (2.11 +/- 0.19 +/- 0.25) x 10(-4), and the cross-section product sigma(e+ e- --> xi(c)(0)X) x B(xi(c)(0) --> xi- pi+) from the continuum is measured to be (388 +/- 39 +/- 41) fb at a center-of-mass energy of 10.58 GeV.

We reexamine the problem of simultaneously describing in a consistent way all radiative and leptonic decays of light mesons (V→ P␥, P→V␥, P→␥␥, V→e ϩ e Ϫ ). For this purpose, we rely on the hidden local symmetry model in both its anomalous and non-anomalous sectors. We show that the SU͑3͒ symmetry breaking scheme proposed by Bando, Kugo and Yamawaki, supplemented with nonet symmetry breaking in the pseudoscalar sector, allows one to reach a nice agreement with all data, except for the K* Ϯ radiative decay. An extension of this breaking pattern allows one to account for this particular decay mode too. Considered together, the whole set of radiative decays provides a pseudoscalar mixing angle P ӍϪ11°and a value for V which is Ӎ3°from that of ideal mixing. We also show that it is impossible, in a practical sense, to disentangle the effects of nonet symmetry breaking and those of glue inside the Ј, using only light meson decays.