6,115 research outputs found

    B meson decays to baryons in the diquark model

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    We study B meson decays to two charmless baryons in the diquark model, including strong and electroweak penguins as well as the tree operators. It is shown that penguin operators can enhance \bar{B} \to \Bb_s \bar{\Bb} considerably, but affect \bar{B} \to \Bb_1 \bar{\Bb}_2 only slightly, where \Bb_{(1,2)} and \Bb_s are non-strange and strange baryons, respectively. The γ\gamma dependence of the decay rates due to tree-penguin interference is illustrated. In principle, some of the \Bb_s \bar{\Bb} modes could dominate over \Bb_1 \bar{\Bb}_2 for γ>90∘\gamma > 90^\circ, but in general the effect is milder than their mesonic counterparts. This is because the O6O_6 operator can only produce vector but not scalar diquarks, while the opposite is true for O1O_1 and O4O_4. Predictions from diquark model are compared to those from the sum rule calculation. The decays \bar{B} \to \Bb_s \bar{\Bb}_s and inclusive baryonic decays are also discussed.Comment: 9 pages, 6 figures, Revte

    Neutrino Masses in a 5D SU(3)WSU(3)_W TeV Unification Model

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    We study the generation of neutrino masses in the SU(3)WSU(3)_W electroweak unified theory in M4×S1/(Z2×Z2′)M_4\times S_1/(Z_2\times Z'_2) spacetime. By appropriate orbifolding, the bulk symmetry SU(3)WSU(3)_W is broken into SU(2)L×U(1)YSU(2)_L \times U(1)_Y at one of the fixed points, where the quarks reside. The leptons form SU(3)WSU(3)_W triplets, localized at the other symmetric fixed point. The fermion masses arise from the bulk Higgs sector containing a triplet and an anti-sextet. We construct neutrino Majorana masses via 1-loop quantum corrections by adding a parity odd bulk triplet scalar. No right-handed neutrino is needed. The neutrino mass matrix is of the inverted hierarchy type. We show that the model can easily accommodate the bi-large mixing angle solution favored by the recent neutrino experiments without much fine tuning of parameters. The constraints from \mu\ra 3e transition and neutrinoless double beta decays are discussed.Comment: 14 pages, 4 figure

    Bulk Higgs Boson Decays in Brane Localized Gravity

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    We embed the Standard Model in the Randall-Sundrum model of 5 dimensional brane localized gravity. The SM gauge and chiral fermion fields are restricted on the 4D visible brane whereas the Higgs and the right-handed neutrino are assumed to be 5D bulk fields. We calculate the effective couplings of the lowest mass Higgs field to the SM fermions and to the gauge bosons and find that the couplings are enhanced. Furthermore, the invisible decay width of a bulk Higgs of mass 150 GeV is shown to be large.Comment: 14 pages, 2 postscript figures, minor typos corrected, two references added, to appear in Physics Letters

    QCD Corrections to b→sγγb\to s\gamma\gamma and Exclusive Bs→γγB_s\to \gamma\gamma Decay

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    The short distance QCD corrections to b→sγγb\to s\gamma \gamma are calculated in the leading logarithmic approximation. The equivalence of operator basis reduction for S-matrix elements by using the equations of motion or by proving a low energy theorem is discussed. We apply the above results to the exclusive Bs→γγB_s\to \gamma\gamma decay. The branching ratio of this decay is found to be 5×10−75\times 10^{-7} in the Standard Model. We also found that QCD corrections modify considerably the ratio between CP-even and CP-odd two-photon amplitudes.Comment: revtex, 15 pages, 2 figures; revised version with corrections from electroweak penguin discussed, the conclusion remains unchange
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