Light New Physics searches with BaBar

Several hypothetical light New Physics particles have been searched using the clean and large electron-positron collision samples collected by the BaBar collaboration around the Υ(4S) resonance. No evidence has been found and 90% confidence level upper limits have been set on a dark photon decaying into electron or muon pairs, on a next-to-minimal supersymmetric Higgs boson decaying to charmed hadrons, and to an exotic π0-like particle that would couple to the tau lepton

Tensor mesons produced in tau lepton decays

Light tensor mesons (T = a_2, f_2 and K_2^*) can be produced in decays of tau leptons. In this paper we compute the branching ratios of tau --> T pi nu decays by assuming the dominance of intermediate virtual states to model the form factors involved in the relevant hadronic matrix element. The exclusive f_2(1270) pi^- decay mode turns out to have the largest branching ratio, of O(10^-4) . Our results indicate that the contributions of tensor meson intermediate states to the three-pseudoscalar channels of tau decays are rather small.Comment: 10 pages, 1 figure. Version accepted for publication in PRD, some typos are corrected and comments are added in section 4. Conclusions remain unchange

The impact of SuperB on flavour physics

This report provides a succinct summary of the physics programme of SuperB, and describes that potential in the context of experiments making measurements in flavour physics over the next 10 to 20 years. Detailed comparisons are made with Belle II and LHCb, the other B physics experiments that will run in this decade. SuperB will play a crucial role in defining the landscape of flavour physics over the next 20 years.Comment: 20 pages, 6 figure

Tau spin correlations and the anomalous magnetic moment

We show that the precise determination of the Tau magnetic properties is possible in the next generation accelerators, specially at B/Flavour factories. We define spin correlation observables suitable to extract the real part of the magnetic form factor that, for the first time, will allow to test the standard model-QED predictions. In particular, the predicted QED-dependence with both the momentum transfer and the lepton mass can be precisely measured. Until now, the most stringent bounds on the $\tau$ magnetic moment $a_\tau$ come from LEP data with strong assumptions on the physics involved on the observed process. In this paper, we find three different combinations of spin correlations of the outgoing Taus that disentangle the magnetic moment form factor of the Tau lepton in the electromagnetic vertex. These combinations of asymmetries also get rid off the contributions coming from Z-mediating amplitudes to the defined correlations. Using unpolarized electron beams and an integrated luminosity of $15 \times 10^{18} b^{-1}$, the sensitivity to the $\tau$ magnetic moment form factor is of the order $10^{-6}$. This sensitivity is two orders of magnitude better than the present existing high- or low-energy bounds on the magnetic moment and would allow its actual measurement with the precision of a few per cent.Comment: 14 pages, 1 figur

Ebstein Anomaly in Pregnancy

A 27-year-old primiparous woman with 28 weeks gestational age was admitted to our hospital with worsening shortness of breath. She was diagnosed with Ebstein’s anomaly three years ago, but preferred to be left untreated. The patient was not cyanotic and her vital signs were stable. Her ECG showed incomplete RBBB and prolonged PR-interval. Blood tests revealed mild anemia. Observation of two-dimensional echo with color flow Doppler study showed Ebstein’s anomaly with PFO as additional defects, EF of 57%, LV and LA dilatation, RV atrialization, severe TR, and moderate PH with RVSP of 44.3 mmHg. The patient then underwent elective sectio caesaria at 30 weeks of gestational age; both the mother and her baby were alive and were in good conditions. Problem: there was an increasing breathlessness in this patient so that there was an increasing need to take a decision for her pregnancy.Ebstein’s anomaly is a complicated congenital anomaly. Medical treatment may be followed for many years in patients with mild forms of Ebstein’s anomaly. Surgery should be considered if there is objective evidence of debasement such as significant enlargement of heart size, reduction of systolic function in echocardiography

Electric dipole moments from flavoured CP violation in SUSY

The so-called supersymmetric flavour and CP problems are deeply related to the origin of flavour and hence to the origin of the SM Yukawa couplings themselves. We show that realistic SU(3) flavour symmetries with spontaneous CP violation reproducing correctly the SM Yukawa matrices can simultaneously solve both problems without ad hoc modifications of the SUSY model. We analyze the leptonic electric dipole moments and lepton flavour violation processes in these models. We show that the electron EDM and the decay mu -> e gamma are naturally within reach of the proposed experiments if the sfermion masses are measurable at the LHC.Comment: 26 pages, 6 figures; added references, corrected typos; added referres suggestions, version accepted in PR

T violation and the unidirectionality of time

An increasing number of experiments at the Belle, BNL, CERN, DA{\Phi}NE and SLAC accelerators are confirming the violation of time reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and calls for a major shift in the way we think about time. Here we show that processes which violate T symmetry induce destructive interference between different paths that the universe can take through time. The interference eliminates all paths except for two that represent continuously forwards and continuously backwards time evolution. Evidence from the accelerator experiments indicates which path the universe is effectively following. This work may provide fresh insight into the long-standing problem of modeling the dynamics of T violation processes. It suggests that T violation has previously unknown, large-scale physical effects and that these effects underlie the origin of the unidirectionality of time. It may have implications for the Wheeler-DeWitt equation of canonical quantum gravity. Finally it provides a view of the quantum nature of time itself.Comment: 24 pages, 5 figures. Final version accepted for publishing in Foundations of Physics. The final publication is available at http://www.springerlink.com/content/y3h4174jw2w78322

SuperB: a linear high-luminosity B Factory

This paper is based on the outcome of the activity that has taken place during the recent workshop on "SuperB in Italy" held in Frascati on November 11-12, 2005. The workshop was opened by a theoretical introduction of Marco Ciuchini and was structured in two working groups. One focused on the machine and the other on the detector and experimental issues. The present status on CP is mainly based on the results achieved by BaBar and Belle. Estabilishment of the indirect CP violation in B sector in 2001 and of the direct CP violation in 2004 thanks to the success of PEP-II and KEKB e+e- asymmetric B Factories operating at the center of mass energy corresponding to the mass of the Y(4s). With the two B Factories taking data, the Unitarity Triangle is now beginning to be overconstrained by improving the measurements of the sides and now also of the angles alpha, and gamma. We are also in presence of the very intriguing results about the measurements of sin(2 beta) in the time dependent analysis of decay channels via penguin loops, where b --> s sbar s and b --> s dbar d. Tau physics, in particular LFV search, as well as charm and ISR physics are important parts of the scientific program of a SuperB Factory. The physics case together with possible scenarios for the high luminosity SuperB Factory based on the concepts of the Linear Collider and the related experimental issues are discussed.Comment: 22 pages, 22 figures, INFN Roadmap Repor

Averages of bb-hadron, cc-hadron, and τ\tau-lepton properties as of summer 2014

This article reports world averages of measurements of $b$-hadron, $c$-hadron, and $\tau$-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through summer 2014. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, $CP$ violation parameters, parameters of semileptonic decays and CKM matrix elements.Comment: 436 pages, many figures and tables. Online updates available at http://www.slac.stanford.edu/xorg/hfag