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B 0  invisible (+ gamma) is sensitive to new physics

B  invisible (+ ). B 0  invisible (+ gamma) is sensitive to new physics Several new physics models predict a small but significantly nonzero branching fraction for B 0  invisible

tyronica-ramirez
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B 0  invisible (+ gamma) is sensitive to new physics

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  1. B invisible (+ ) • B0 invisible (+ gamma) is sensitive to new physics • Several new physics models predict a small but significantly nonzero branching fraction for B0 invisible • Dedes, Dreiner, & Richardson hep-ph/0106199 (SUSY model, attempt to explain NuTeV anomaly, B (B0 invisible) = O(10-6)) • Agashe, Deshpande, & Wu hep-ph/0006122 Agashe & Wu hep-ph/0010117 Davoudiasl, Langacker, & Perelstein hep-ph/0201128 (Large extra dimensions, B(B0 invisible) = O(10-7)) • Diagrams (in SM): • Standard model contamination is small and well-predicted. • Helicity suppression kills SM decay B0. Even without such suppression (B0), these are still second-order weak decays. • Lu & Zhang hep-ph/9604378 B (B0 ) = 2.5 x 10-9 in SM

  2. Invisible B Decays? B0gD(*)- l+ n (K+p-) p- (K+p-p0) p- (K+p- p+p-) p- K+p- p- • Wouldn’t something as unusual as an invisible decay have been noticed already? • There have been no significant limits on invisible decays of heavy flavor at all. Invisible decays can easily elude notice – branching fractions could even be up to order 1-5% without being in conflict with any previous B physics results. • If a B were to just disappear, how would one reconstruct it? • The Y(4S) is a unique environment for searching for these types of decays. If one reconstructs a B, one knows that another must have been produced. One reconstructs one B and looks for nothing else in the event. • D(*)l where D*→D0π or D→Kππ is reconstructed • D0 is reconstructed to 3 modes: Kπ, K3π, and Kππ0 • Mass cuts used in reconstruction: ±40 MeV for all modes except for Kππ0 (±70), 130 < Δm(D*-D0) < 170 MeV. • Also reconstruct D(*0)l for “B± → invisible” check • Efficiency for tag reconstruction: 0.2% • Then, rest of event is observed for consistency with no tracks nor neutral energy(+ machine background) …

  3. B  invisible signal plots • Likelihood fit: Nsignal = 20.6 ± 9.0 (stat.) D mass Data MC Data MC Data MC Kπ Kπππ Kππ0 D mass Data MC Kππ ETotLeft ETotLeft

  4. B  invisible (+ ) Conclusions Now published as: Phys. Rev. Lett. 93, 091802 • B0 invisible (+ g) is sensitive to new physics, and had not previously been measured or constrained. • Experimentally-motivated SUSY and extra-dimensions models can give a significant rate for this process. • We obtain the following limits: • We are now updating the analysis for the full Runs 1-5 dataset (~375 million B0 decays). • Expect an updated publication early this Fall! B (B0 invisible) < 23.8 x 10-5 B(B0 invisible + ) < 5.0 x 10-5

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