相关论文: Studies on $\tau$ decays at Belle II
We present the results of a search for the charged-lepton-flavor violating decays $B^0 \rightarrow K^{*0}\tau^\pm \ell^{\mp}$, where $\ell^{\mp}$ is either an electron or a muon. The results are based on 365 fb$^{-1}$ and 711 fb$^{-1}$…
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+e^-$ collider is a substantial upgrade of the B factory facility at KEK in Tsukuba, Japan. It aims to record a factor of 50 times more data than its predecessor. The experiment…
We present the status of the KEKB collider and the Belle detector upgrade, along with several examples of physics measurements to be performed with Belle II at Super KEKB.
We review world-average measurements of the tau lepton electroweak couplings, in both decay (including Michel parameters) and in production ($Z^0\to \tau^+\tau^-$ and $W^-\to\tau^-\nubar_\tau$). We review the searches for anomalous weak and…
The anomalous magnetic moment of the tau lepton, a_tau = (g_tau - 2)/2, is a sensitive probe of new physics but is extremely difficult to measure precisely in contrast to electron and muon moments. The best experimental limits were set by…
Among the charged leptons, the $\tau$ electric dipole moment~($d_\tau$) is the least constrained. We show that the Im[$d_\tau$] imposes strong constraints on new physics that have yet to be discussed. Motivated in particular by the Super…
B-factories provide a unique environment to test the standard model in search for new physics. The Belle and Belle II experiments succeeded each other at KEK, in Tsukuba, Japan. During its lifetime, Belle collected $1{\,ab}^{-1}$ of data;…
We present a search for the decay B -> tau nu in a 140 fb^-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric B factory. Combinatorial and continuum backgrounds are suppressed by selecting a…
Belle II is a major upgrade of the Belle experiment and will operate at the $B$-factory SuperKEKB in Japan. Here we discuss the expected sensitivity of Belle II for $D^0 - \bar{D}^0$ mixing and $CP$ violation measurements in the charm…
Several hundred million tau decays have been studied with the BaBar detector at the PEP-II e+e- collider at the SLAC National Accelerator Laboratory. Recent results on Charged Current Lepton Universality and two independent measurements of…
With the full data sample of $772 \times 10^6$ $B{\bar B}$ pairs recorded by the Belle detector at the KEKB electron-positron collider, the decay $\bar{B} \rightarrow D^* \tau^- \bar{\nu}_\tau$ is studied with the hadronic $\tau$ decays…
The evaluation, systematic analysis and numerical study of the semileptonic $\tau$-lepton decays with two mesons in the final state has been made in the frame of the standard model extended by right handed neutrinos. In the analysis,…
We present the measurements, performed by the Belle II experiment, related to the B and D meson decays. These results are based on 63 fb$^{-1}$ and 9 fb$^{-1}$ of $e^+e^-$ collision data recorded by the Belle II detector at a center-of-mass…
We present measurements of the first to fourth moments of the lepton mass squared $q^2$ of \mbox{$B \to X_c \, \ell\, \bar \nu_{\ell}$} decays for $\ell = e, \mu$ and with $X_c$ a hadronic system containing a charm quark. These results use…
Rare decays mediated by $b \to s \nu \bar \nu$ transitions have been reported by the Belle II experiment. The branching ratio of the decay $B^+ \to K^+ \nu \bar \nu$ is found to be enhanced with respect to the standard model value. If taken…
We have searched for a CP violation signature arising from an electric dipole moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an optimal observable method and 29.5 fb^{-1} of data collected with the Belle detector…
We consider light neutralinos of mass about 1 GeV, produced from $\tau$ lepton rare decays at Belle II, in the context of R-parity-violating (RPV) supersymmetry. With large and clean samples of $\tau$ leptons produced at the Belle II…
The Belle II experiment is a high-energy physics experiment at the SuperKEKB electron-positron collider. Using Belle II data, high precision measurement of rare decays and CP-violation in heavy quarks and leptons can be performed to probe…
The Belle II experiment at the SuperKEKB collider is a major upgrade of the KEK "$B$ factory" facility in Tsukuba, Japan. Phase 1 commissioning of the main ring of SuperKEKB has started in February 2016 and first physics data will be…
We update our search for the lepton flavor violating tau -> mu gamma and tau -> e gamma decays based on 535/fb of data accumulated at the Belle experiment. No signal is found and we set preliminary 90% confidence level upper limits: B(tau…