Rare decays at LHCb Lafferty, G.D.
Nuclear and particle physics proceedings,
06/2015, Letnik:
263-264
Journal Article
Recenzirano
Odprti dostop
We review recent results from the LHCb experiment on studies of particle decays that are forbidden or rare in the Standard Model. The studies include searches for lepton flavour violating decays of ...the τ lepton and the B and D mesons, and of B and D meson decays that would be mediated by Majorana neutrinos. Results are also presented for the rare processes Bs→μ+μ− and B0→μ+μ−, D0→π+π−μ+μ−, b→sγ transitions, and B→K(⁎)μ+μ−.
Recent results are presented on searches for light CP-odd Higgs bosons and dark photons using data from the BaBar experiment at the PEP II asymmetric energy e+e− collider. The light Higgs bosons are ...sought via their production in radiative ϒ(1S) decays and their subsequent decays to gg and ss¯ final states. The search for dark photons A′ involves radiative production e+e−→γA′ with A′→e+e− or μ+μ−. No signals are observed.
When a data point, measured over a bin of finite width, is to be compared to theoretical or model frequency distributions, neither the central value of the bin nor the weighted mean value (the ...barycentre) of the abscissa within the bin is the appropriate place to plot the data point. It is shown that such data points ought to appear where the value of the predicted function is equal to its mean value over the wide bin. Some consequences of commonly used but incorrect alternative data presentation methods in particle physics are discussed.
A new dark sector antibaryon, denoted ψ_{D}, could be produced in decays of B mesons. This Letter presents a search for B^{+}→ψ_{D}+p (and the charge conjugate) decays in e^{+}e^{-} annihilations at ...10.58 GeV, using data collected in the BABAR experiment. Data corresponding to an integrated luminosity of 398 fb^{-1} are analyzed. No evidence for a signal is observed. Branching fraction upper limits in the range from 10^{-7}-10^{-5} are obtained at 90% confidence level for masses of 1.0<m_{ψ_{D}}<4.3 GeV/c^{2}. The result is also reinterpreted to provide the first limits on a supersymmetric model with R-parity violation and a light neutralino.
Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak ...bosons, these particles could be emitted in flavor-changing B meson decays. We report herein a search for an ALP, a, in the reaction B^{±}→K^{±}a, a→γγ using data collected by the BABAR experiment at SLAC. No significant signal is observed, and 90% confidence level upper limits on the ALP coupling to electroweak bosons are derived as a function of ALP mass, improving current constraints by several orders of magnitude in the range 0.175 GeV<m_{a}<4.78 GeV.
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