208 research outputs found

    b -> d Penguins: CP Violation, General Lower Bounds on the Branching Ratios and Standard Model Tests

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    With the wealth of new data from the B-factories, b -> d penguin decays become available for study, in addition to their b -> s counterparts that have proven an indespensable tool for the exploration of new-physics effects in flavour physics. A prominent example of the b -> d penguin transitions is Bˉd0→K0Kˉ0\bar B^0_d \to K^0 \bar K^0. We show that this decay can be charaterized in the Standard Model by a surface in the observable space of the direct and mixing-induced CP asymmetries and the branching ratio. The form of this surface, which is theoretically clean, implies a lower bound for the branching ratio that has recently been confirmed experimentally. If future measurements of the CP asymmetries yield a point away from the SM surface, this would be an interesting signal of new physics. We point out that the hadronic parameters in Bˉd0→K0Kˉ0\bar B^0_d \to K^0 \bar K^0 that parameterize the position on the SM surface are related to hadronic parameters in the B -> pi K system. The fact that the branching ratio of Bˉd0→K0Kˉ0\bar B^0_d \to K^0 \bar K^0 is very close to its lower bound yields interesting implications for B -> pi K even without knowledge of the CP asymmetries of Bˉd0→K0Kˉ0\bar B^0_d \to K^0 \bar K^0. The mechanism that produces the lower bound for Bˉd0→K0Kˉ0\bar B^0_d \to K^0 \bar K^0 is actually much more general; we derive lower bounds for various other b -> d penguin-induced processes, including B -> rho gamma and B±→K(∗)±K(∗)B^\pm \to K^{(\ast)\pm} K^{(\ast)}. Some of these theoretical lower bounds are very close to the current experimental upper bounds.Comment: 4 pages, 2 figures. Contribution to the proceedings of EPS-HEP200

    B -> pi pi, New Physics in B -> pi K and Implications for Rare K and B Decays

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    The measured B -> pi pi, pi K branching ratios exhibit puzzling patterns. We point out that the B -> pi pi hierarchy can be nicely accommodated in the Standard Model (SM) through non-factorizable hadronic interference effects, whereas the B -> pi K system may indicate new physics (NP) in the electroweak (EW) penguin sector. Using the B -> pi pi data and the SU(3) flavour symmetry, we may fix the hadronic B -> pi K parameters, which allows us to show that any currently observed feature of the B -> pi K system can be easily explained through enhanced EW penguins with a large CP-violating NP phase. Restricting ourselves to a specific scenario, where NP enters only through Z^0 penguins, we derive links to rare K and B decays, where an enhancement of the K_L-> pi^0 nu nu_bar rate by one order of magnitude, with BR(K_L -> pi^0 nu nu_bar) > BR(K^+ -> pi^+ nu nu_bar), BR(K_L -> pi^0 e^+ e^-)=O(10^{-10}), (\sin2\beta)_{pi nu nu_bar} K* mu^+ mu^-, are the most spectacular effects. We address also other rare K and B decays, epsilon'/epsilon and B_d -> phi K_S.Comment: 6 pages, LaTeX, reference added and a few typos correced, to appear in Physical Review Letter

    General Lower Bounds for b -> d Penguin Processes

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    For the exploration of flavour physics, b -> d penguin processes are an important aspect, with the prominent example of \bar B^0_d -> K^0 \bar K^0. We recently derived lower bounds for the CP-averaged branching ratio of this channel in the Standard Model; they were found to be very close to the corresponding experimental upper limits, thereby suggesting that \bar B^0_d -> K^0 \bar K^0 should soon be observed. In fact, the BaBar collaboration subsequently announced the first signals of this transition. Here we point out that it is also possible to derive lower bounds for \bar B -> \rho \gamma decays, which are again surprisingly close to the current experimental upper limits. We show that these bounds are realizations of a general bound that holds within the Standard Model for b -> d penguin processes, allowing further applications to decays of the kind B^\pm -> K^{(\ast)\pm} K^{(\ast)} and B^\pm -> \pi^\pm \ell^+ \ell^-, \rho^\pm \ell^+ \ell^-.Comment: Minor changes, to appear as rapid communication in Phys. Rev

    A conceptual modeling approach for supply chain event management (SCEM)

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    The management of supply chains is a very comprehensive task. Predictability and response to incidents in process executions are challenging. With Supply Chain Event Management (SCEM), researchers propose an approach for overcoming these problems through proactive monitoring and notification of crucial process activities across the supply chain. The identification and definition of such crucial activities and information needs are necessary to handle possible abnormalities although they are challenging task which have not been solved in SCEM research so far. Hence, we propose a modeling approach which allows the conceptual specification of an adequate information exchange along the supply chain. With our approach we focus on the specification of relevant logistical objects, the definition of possible events, and the design of notifications for decision makers in the supply chain
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