Related papers: Tau decays and dark-sector searches at BaBar

We present the results of a search for the decay B0 --> tau+tau- in a data sample of (232 +- 3) x 10^6 Upsilon(4S) --> BBbar decays using the BABAR detector. Certain extensions of the Standard Model predict measurable levels of this…

We have searched for tau lepton decays, tau- -> Lambda-bar pi- and tau- -> Lambda pi-, that simultaneously violate the conservation of the lepton and baryon number using a data sample of 154 fb^{-1} collected with the Belle detector at the…

We report on a search for the lepton-flavor-violating processes $e^+e^- \to \mu^+\tau^-$ and $e^+e^- \to e^+\tau^-$. The data sample corresponds to an integrated luminosity of 211 fb$^{-1}$ recorded by the BaBar experiment at the SLAC…

We report preliminary measurements of the branching fractions of the decays $\tau \to K\, n\pi^0\, \nu$ ($n = 0,1,2,3$) and $\tau \to \pi\, n\pi^0\, \nu$ ($n = 3,4$), excluding the contributions that proceed through the decay of…

We have searched for the violation of baryon number B and lepton number L in the (B-L)-conserving modes tau- -> anti-Lambda0 pi- and tau- -> anti-Lambda0 K- as well as the (B-L)-violating modes tau- -> Lambda0 pi- and tau- -> Lambda0 K-…

The possibility of a dark sector weakly coupling to Standard Model (SM) particles through new light mediators is explored at the Belle II experiment. We present here results from three different searches, for a long-lived (pseudo)scalar…

We have studied hadronic tau decay modes involving an eta meson using 490 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The following branching fractions have been measured: B(tau- -> K- eta…

This thesis presents a study of the decays $\tau\rightarrow e\nu\overline{\nu}$ identified after a selection of $\tau^+\tau^-$ events produced in $e^+e^-$ collisions at LEP. These collisions, predominantly mediated by a $Z^0$ boson, offer a…

We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR)…

Searches for lepton-flavor-violating decay of a tau lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 +- 7) x 10^6 tau decays collected by the BaBar detector near the Upsilon(4S), Upsilon(3S)…

Decays of B mesons into final states containing a tau lepton are sensitive to new charged-current interactions that break lepton-flavor universality. These decays have been studied only at e+e- colliders, where the low-background…

In a sample of 471 million BB events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B -> K(*) l+ l-, where l+ l- is either e+e- or mu+mu-. We report results on partial branching fractions and isospin…

We have searched for lepton-flavor-violating $\tau$ decays with a pseudoscalar meson ($\eta$, $\eta'$ {and} $\pi^0$) using a data sample of 401 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No…

We report the results of a search for a W' boson produced in p-pbar collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W' -> mu nu and…

We report a search for the rare decays B+ to D+ K0 and B+ to D+ K*0 in an event sample of approximately 465 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find no significant…

We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR)…

We present the first evidence of the decay B- --> tau- nu_tau-bar using 414 fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Events are tagged by fully reconstructing…

The "\tau\to 3\pi\eta\nu" decay with the "\eta \to \gamma\gamma" mode is studied using 384 fb^-1 of data collected by the BaBar detector. The branching fraction is measured to be (1.60+/-0.05+/-0.11)x10^-4. It is found that "\tau \to f1 \pi…

We present the results of a search for a dark photon decaying to $e^+e^-$ or $\mu^+\mu^-$ in the \babar\ detector. We find no evidence for such a dark photon and set upper limits on the dark mixing as a function mass, tightening the…

The branching fraction of the tau- --> 3h- 2h+ nu decay (h= pi, kaon) is measured with the BaBar detector to be (8.56 +/- 0.05 +/- 0.42)E-04 where the first error is statistical and the second systematic. The observed structure of this…