834 research outputs found

    Can one detect new physics in I=0 and/or I=2 contributions to the decays B --> pi pi?

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    We study the effects of new-physics contributions to B --> pi pi decays, which can be parametrized as four new complex quantities. A simple analysis is provided by utilizing the reparametrization invariance of the decay amplitudes. We find that six quantities can be reabsorbed into the definitions of Standard Model-like parameters. As a result, the usual isospin analysis provides only two constraints on new physics which are independent of estimates for the Standard Model contributions. In particular, we show that one is not sensitive to new physics affecting the I=0 amplitudes. On the other hand, I=2 new physics can be detected, and its parameters can be measured by using independent determinations of the weak phases. We obtain constraints on these new-physics parameters through a fit to the current experimental data.Comment: 8 pages, RevTe

    Measurements of New Physics in B -> pi pi Decays

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    If new physics (NP) is present in B -> pi pi decays, it can affect the isospin I=2 or I=0 channels. In this paper, we discuss various methods for detecting and measuring this NP. The techniques have increasing amounts of theoretical hadronic input. If NP is eventually detected in B -> pi pi -- there is no evidence for it at present -- one will be able to distinguish I=2 and I=0, and measure its parameters, using these methods.Comment: 24 pages, no figures, revte

    The B -> pi K Puzzle and New Physics

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    The present B -> pi K data is studied in the context of the standard model (SM) and with new physics (NP). We confirm that the SM has difficulties explaining the B -> pi K measurements. By adopting an effective-lagrangian parametrization of NP effects, we are able to rule out several classes of NP. Our model-independent analysis shows that the B -> pi K data can be accommodated by NP in the electroweak penguin sector.Comment: 4 pages (revtex

    Polarization States in B -> rho K* and New Physics

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    The standard-model explanations of the anomalously-large transverse polarization fraction fT in B -> phi K* can be tested by measuring the polarizations of the two decays B+ -> rho+ K*0 and B+ -> rho0 K*+. For the scenario in which the transverse polarizations of both B -> rho K* decays are predicted to be large, we derive a simple relation between the fT's of these decays. If this relation is not confirmed experimentally, this would yield an unambiguous signal for new physics. The new-physics operators which can account for the discrepancy in B -> pi K decays will also contribute to the polarization states of B -> rho K*. We compute these contributions and show that there are only two operators which can simultaneously account for the present B -> pi K and B -> rho K* data. If the new physics obeys an approximate U-spin symmetry, the B -> phi K* measurements can also be explained.Comment: 20 pages, latex, no figures. Minor changes to references and Table 1. Minor modification of terms; more complete description of triple-product asymmetry. Analysis and conclusions unchange

    Regulation of ecto‐apyrase CD39 (ENTPD1) expression by phosphodiesterase III (PDE3)

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154432/1/fsb2027011011.pd

    Down Selection of Polymerized Bovine Hemoglobins for Use as Oxygen Releasing Therapeutics in a Guinea Pig Model

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    Editor's Highlight: The development of hemoglobin-based oxygen carriers (HBOCs) as a replacement for whole-blood transfusions has been impeded by their systemic toxicity. This paper presents data from a series of HBOCs, demonstrating one candidate that meets predetermined safety criteria. This approach may allow the development of an acceptable blood substitute for human us

    Prospects for the direct detection of neutralino dark matter in orbifold scenarios

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    We analyse the phenomenology of orbifold scenarios from the heterotic superstring, and the resulting theoretical predictions for the direct detection of neutralino dark matter. In particular, we study the parameter space of these constructions, computing the low-energy spectrum and taking into account the most recent experimental and astrophysical constraints, as well as imposing the absence of dangerous charge and colour breaking minima. In the remaining allowed regions the spin-independent part of the neutralino-proton cross section is calculated and compared with the sensitivity of dark matter detectors. In addition to the usual non universalities of the soft terms in orbifold scenarios due to the modular weight dependence, we also consider D-term contributions to scalar masses. These are generated by the presence of an anomalous U(1), providing more flexibility in the resulting soft terms, and are crucial in order to avoid charge and colour breaking minima. Thanks to the D-term contribution, large neutralino detection cross sections can be found, within the reach of projected dark matter detectors.Comment: 51 pages, 25 figure

    RORα Coordinates Reciprocal Signaling in Cerebellar Development through Sonic hedgehog and Calcium-Dependent Pathways

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    AbstractThe cerebellum provides an excellent system for understanding how afferent and target neurons coordinate sequential intercellular signals and cell-autonomous genetic programs in development. Mutations in the orphan nuclear receptor RORα block Purkinje cell differentiation with a secondary loss of afferent granule cells. We show that early transcriptional targets of RORα include both mitogenic signals for afferent progenitors and signal transduction genes required to process their subsequent synaptic input. RORα acts through recruitment of gene-specific sets of transcriptional cofactors, including β-catenin, p300, and Tip60, but appears independent of CBP. One target promoter is Sonic hedgehog, and recombinant Sonic hedgehog restores granule precursor proliferation in RORα-deficient cerebellum. Our results suggest a link between RORα and β-catenin pathways, confirm that a nuclear receptor employs distinct coactivator complexes at different target genes, and provide a logic for early RORα expression in coordinating expression of genes required for reciprocal signals in cerebellar development
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