Related papers: The Current Status of g-2
Selected results from tau analyses performed using the BaBar detector at the SLAC National Accelerator Laboratory are presented. A precise measurement of the tau mass and the tau{+} tau{-} mass difference is undertaken using the hadronic…
The BABAR experiment participates to the global endeavor for a precise prediction of the anomalous magnetic moment of the muon by evaluating the contribution of hadronic processes to the vacuum polarization. After its last result published…
Recently, the Belle collaboration reported the first measurements of the $\tau^- \to\nu_{\tau}\pi^-e^+e^-$ branching fraction and the spectrum of the pion-dielectron system. In an analysis previous to Belle's results, we evaluated this…
We study the implications of several recent high-precision measurements of the pion form factor in the region of the rho-omega interference "shoulder" for (i) the extraction of the rho-omega mixing matrix element, Pi_{\rho\omega}(m_rho^2),…
The strength of the interaction of three pions and a photon, $F_{3\pi}$ is predicted by the axial anomaly in terms of the pion decay constant, a relation that is frequently used to constrain low-energy radiative processes involving pions,…
It is believed that one can extract more accurate information of the pion distribution amplitude from the pion-photon transition form factor (TFF) due to the single pion in this process. However the BABAR and Belle data of the pion-photon…
We discuss the prospects for improving the precision on the hadronic corrections to the anomalous magnetic moment of the muon, and the plans of the Muon $g-2$ Theory Initiative to update the Standard Model prediction.
The result of lowest-order perturbation theory calculations of the photon and positron spectra in radiative pion(e2) decay are generalized to all orders of perturbation theory using the structure-function method. An additional source of…
The discrepancy between the Standard Model theory and experimental measurement of the muon magnetic moment anomaly, $a_{\mu}=\left(g_{\mu}-2\right)/2$, is connected to precision electroweak (EW) predictions via their common dependence on…
We give an update on the status of the hadronic light-by-light scattering contribution to the muon g-2. We review recent work by various groups, list some of the open problems and give an outlook on how to better control the uncertainty of…
The BaBar collaboration has an extensive program of studying hadronic cross sections in low-energy e+e- collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted…
The $\mu\nu$SSM is a highly predictive alternative model to the MSSM. In particular, the electroweak sector of the model can explain the longstanding discrepancy between the experimental result for the anomalous magnetic moment of the muon,…
The $\tau^- \to \pi^-\eta\nu_{\tau}$ decay is forbidden in the Standard Model in the limit of exact $G$-parity, it becomes a rare decay due to isospin symmetry breaking and it is very sensitive to the effects of effective scalar…
The recently measured B -> tau nu branching ratio allows to test the Standard Model by probing virtual effects of new heavy particles, such as a charged Higgs boson. The accuracy of the test is currently limited by the experimental error on…
The status of the ISR analysis with BaBar is presented. Preliminary results are given on the process e+e- --> 2pi+ 2pi- and J/psi decays including a determination of its total width and the branching ratios into 2pi+ 2pi-, K+ K- pi+ pi-,…
We have calculated the ratios $R_{e/\mu}^{(P)} \equiv \Gamma(P \to e \bar{\nu}_e [\gamma])/ \Gamma(P \to \mu \bar{\nu}_\mu [\gamma])$ ($P=\pi,K$) in Chiral Perturbation Theory up to $\mathcal{O}(e^2p^4)$, finding $R_{e/\mu}^{(\pi)} =…
We present the recent BaBar searches for the leptonic decay B+ --> tau+ nu and for the rare decay B --> K(*) nu nubar, using a data sample of about 470 x 10^6 BB pairs. Both searches use a technique in which one B meson is hadronically…
We present a selection of recent results from studies of rare hadronic B decays based on a sample of 232 million BBbar pairs, corresponding to an integrated luminosity of 211/fb, which were recorded with the BaBar detector at the PEP-II…
We study polarized cross-sections and forward-backward asymmetry for the process $e^+e-\to \tau^+\tau^-$ in the stabilized Randall-Sundrum scenario. It is shown that there is substantial deviation from the Standard Model predictions, both…
We construct an effective non-relativistic quantum field theory that describes bound states of pi+ pi- pairs and their hadronic decays. We then derive a general expression for the lifetime of the ground state at next-to-leading order in…