335 research outputs found

    Extracting gamma and Penguin Topologies through CP Violation in B_s^0 -> J/psi K_S

    Full text link
    The B_s^0 -> J/psi K_S decay has recently been observed by the CDF collaboration and will be of interest for the LHCb experiment. This channel will offer a new tool to extract the angle gamma of the unitarity triangle and to control doubly Cabibbo-suppressed penguin corrections to the determination of sin(2beta) from the well-known B_d^0 -> J/psi K_S mode with the help of the U-spin symmetry of strong interactions. While any competitive determination of gamma is interesting, the latter aspect is particularly relevant as LHCb will enter a territory of precision which makes the control of doubly Cabibbo-suppressed Standard-Model corrections mandatory. Using the data from CDF and the e^+e^- B factories as a guideline, we explore the sensitivity for gamma and the penguin parameters and point out that the B_s^0-\bar B_s^0 mixing phase phi_s, which is only about -2 deg in the Standard Model but may be enhanced through new physics, is a key parameter for these analyses. We find that the mixing-induced CP violation S(B_s^0 -> J/psi K_S) shows an interesting correlation with sin(phi_s), which serves as a target region for the first measurement of this observable at LHCb.Comment: 20 pages, 8 figure

    High Frequency of Extra-Pair Paternity in Eastern Kingbirds

    Get PDF
    Genetic parentage in the socially monogamous and territorial Eastern Kingbird( Tyrannust tyrannus) was examined in a central New York population by multilocus DNA fingerprinting. Extra-pair young were identified in 60% (12 of 20) of nests. Of the 64 nestlings profiled, 42% were sired by extra-pair males, but no cases of conspecific brood parasitism were detected. These results are markedly different from a previous electrophoretic study of the same species in a Michigan population, which reported 39% of nestlings were unrelated to one (typically the mother, quasiparasitismo)r both (conspecificb roodp arasitism) of the putative parents. In the New York population, extra-pairp aternityw as most common among females that returned to breed on a former territory. Among females that were new to a breeding territory, extrapair paternity increased directly with breeding density. Although the power of the tests was low, neither breeding synchrony nor male experience with a breeding territory appeared to be associated with the occurrence of extra-pair young

    Exploring CP Violation with BcB_c Decays

    Full text link
    We point out that the pure ``tree'' decays Bc±Ds±DB_c^\pm\to D^\pm_s D are particularly well suited to extract the CKM angle γ\gamma through amplitude relations. In contrast to conceptually similar strategies using B±K±DB^\pm\to K^\pm D or BdK0DB_d\to K^{\ast0} D decays, the advantage of the BcB_c approach is that the corresponding triangles have three sides of comparable length and do not involve small amplitudes. Decays of the type Bc±D±DB_c^\pm\to D^\pm D -- the UU-spin counterparts of Bc±Ds±DB_c^\pm\to D^\pm_s D -- can be added to the analysis, as well as channels, where the Ds±D^\pm_s- and D±D^\pm-mesons are replaced by higher resonances.Comment: 9 pages, LaTeX, 3 figures, reference adde

    Lunar Surface Cosmic Ray Experiment S-152, Apollo 16 General Electric experiment final report

    Get PDF
    This report presents the work done and reported under contract NAS 9-11468. The investigation was directed at determining the energy spectra and abundances of low energy heavy cosmic rays during the Apollo 16 mission. The cosmic rays were detected using passive, solid particle track detectors.Contract No. NAS 9-11468R. L. Fleischer ... and others ; Principal Investigator, R. L. Fleischer

    Towards new frontiers in the exploration of charmless non-leptonic B decays

    Get PDF
    Non-leptonic BB decays into charmless final states offer an important laboratory to study CP violation and the dynamics of strong interactions. Particularly interesting are Bs0KK+B^0_s\to K^-K^+ and Bd0ππ+B^0_d\to\pi^-\pi^+ decays, which are related by the UU-spin symmetry of strong interactions, and allow for the extraction of CP-violating phases and tests of the Standard Model. The theoretical precision is limited by UU-spin-breaking corrections and innovative methods are needed in view of the impressive future experimental precision expected in the era of Belle II and the LHCb upgrade. We have recently proposed a novel method to determine the Bs0B_s^0-Bˉs0\bar{B}_s^0 mixing phase ϕs\phi_s from the Bs0KK+B_s^0\to K^-K^+, Bd0ππ+B_d^0\to \pi^-\pi^+ system, where semileptonic Bs0K+νB^0_s\to K^-\ell^+\nu_\ell, Bd0π+νB^0_d\to \pi^-\ell^+\nu_\ell decays are a new ingredient and the theoretical situation is very favourable. We discuss this strategy in detail, with a focus on penguin contributions as well as exchange and penguin-annihilation topologies which can be probed by a variety of non-leptonic BB decays into charmless final states. We show that a theoretical precision as high as O(0.5){\cal O}(0.5^\circ) for ϕs\phi_s can be attained in the future, thereby offering unprecedented prospects for the search for new sources of CP violation.Comment: 50 pages, 25 figure

    CP violation and CKM phases from angular distributions for BsB_s decays into admixtures of CP eigenstates

    Get PDF
    We investigate the time-evolutions of angular distributions for BsB_s decays into final states that are admixtures of CP-even and CP-odd configurations. A sizable lifetime difference between the BsB_s mass eigenstates allows a probe of CP violation in time-dependent untagged angular distributions. Interference effects between different final state configurations of BsDs+DsB_s\to D^{*+}_s D^{*-}_s, J/ψϕJ/\psi \phi determine the Wolfenstein parameter η\eta from untagged data samples, or -- if one uses Vub/Vcb|V_{ub}|/|V_{cb}| as an additional input -- the notoriously difficult to measure CKM angle γ\gamma. Another determination of γ\gamma is possible by using isospin symmetry of strong interactions to relate untagged data samples of BsK+KB_s\to K^{\ast+} K^{\ast-} and BsK0K0B_s\to K^{\ast0} \overline{K^{\ast0}}. We note that the untagged angular distribution for Bsρ0ϕB_s\to\rho^0 \phi provides interesting information about electroweak penguins.Comment: 19 pages, LaTeX, no figure

    In Pursuit of New Physics with B_s Decays

    Get PDF
    The presence of a sizeable CP-violating phase in B_s^0-B_s^0-bar mixing would be an unambiguous signal of physics beyond the Standard Model. We analyse various possibilities to detect such a new phase considering both tagged and untagged decays. The effects of a sizeable width difference Delta Gamma between the B_s mass eigenstates, on which the untagged analyses rely, are included in all formulae. A novel method to find this phase from simple measurements of lifetimes and branching ratios in untagged decays is proposed. This method does not involve two-exponential fits, which require much larger statistics. For the tagged decays, an outstanding role is played by the observables of the time-dependent angular distribution of the B_s -> J/psi [-> l^+ l^-] \phi [-> K^+K^-] decay products. We list the formulae needed for the angular analysis in the presence of both a new CP-violating phase and a sizeable Delta Gamma, and propose methods to remove a remaining discrete ambiguity in the new phase. This phase can therefore be determined in an unambiguous way.Comment: minor changes, lattice prediction of Delta Gamma updated, appears in PR

    Exploring CP Violation through Correlations in B --> pi K, B_d --> pi^+pi^-, B_s --> K^+K^- Observable Space

    Full text link
    We investigate allowed regions in observable space of B --> pi K, B_d --> pi^+pi^- and B_s --> K^+K^- decays, characterizing these modes in the Standard Model. After a discussion of a new kind of contour plots for the BπKB\to\pi K system, we focus on the mixing- induced and direct CP asymmetries of the decays B_d --> pi^+pi^- and B_s--> K^+K^-. Using experimental information on the CP-averaged B_d --> pi^{+/-}K^{+/-} and B_d --> pi^+pi^- branching ratios, the relevant hadronic penguin parameters can be constrained,implying certain allowed regions in observable space. In the case of B_d --> pi^+pi^-, an interesting situation arises now in view of the recent B-factory measurements of CP violation in this channel, allowing us to obtain new constraints on the CKM angle gamma as a function of the B^0_d--\bar{B^0_d} mixing phase phi_d=2beta, which is fixed through A_{CP}^{mix}(B_d --> J/psi K_S) up to a twofold ambiguity. If we assume that A_{CP}^{mix}(B_d --> pi^+pi^-) is positive, as indicated by recent Belle data, and that phi_d is in agreement with the ``indirect'' fits of the unitarity triangle, also the corresponding values for gamma around 60 degrees can be accommodated. On the other hand, for the second solution of phi_d, we obtain a gap around gamma ~ 60 degrees. The allowed region in the space of A_{CP}^{mix}(B_s --> K^+K^-) and A_{CP}^{dir}(B_s --> K^+K^-) is very constrained in the Standard Model, thereby providing a narrow target range for run II of the Tevatron and the experiments of the LHC era.Comment: 34 pages, LaTeX, 12 figures. More detailed introduction and a few Comments added, conclusions unchanged. To appear in Phys. Rev.

    Molecular assays for the detection of microRNAs in prostate cancer

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are small non-coding RNAs (about 21 to 24 nucleotides in length) that effectively reduce the translation of their target mRNAs. Several studies have shown miRNAs to be differentially expressed in prostate cancer, many of which are found in fragile regions of chromosomes. Expression profiles of miRNAs can provide information to separate malignancies based upon stage, progression and prognosis. Here we describe research prototype assays that detect a number of miRNA sequences with high analytical sensitivity and specificity, including miR-21, miR-182, miR-221 and miR-222, which were identified through expression profiling experiments with prostate cancer specimens. The miRNAs were isolated, amplified and quantified using magnetic bead-based target capture and a modified form of Transcription-Mediated Amplification (TMA).</p> <p>Results</p> <p>Analytical sensitivity and specificity were demonstrated in model system experiments using synthetic mature microRNAs or <it>in vitro </it>miRNA hairpin precursor transcripts. Research prototype assays for miR-21, miR-182, miR-221 and miR-222 provided analytical sensitivities ranging from 50 to 500 copies of target per reaction in sample transport medium. Specific capture and detection of mature miR-221 from complex samples was demonstrated in total RNA isolated from human prostate cancer cell lines and xenografts.</p> <p>Conclusion</p> <p>Research prototype real-time TMA assays for microRNAs provide accurate and reproducible quantitation using 10 nanograms of input total RNA. These assays can also be used directly with tissue specimens, without the need for a preanalytic RNA isolation step, and thus provide a high-throughput method of microRNA profiling in clinical specimens.</p

    Genetic structure along an elevational gradient in Hawaiian honeycreepers reveals contrasting evolutionary responses to avian malaria

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The Hawaiian honeycreepers (Drepanidinae) are one of the best-known examples of an adaptive radiation, but their persistence today is threatened by the introduction of exotic pathogens and their vector, the mosquito <it>Culex quinquefasciatus</it>. Historically, species such as the amakihi (<it>Hemignathus virens</it>), the apapane (<it>Himatione sanguinea</it>), and the iiwi (<it>Vestiaria coccinea</it>) were found from the coastal lowlands to the high elevation forests, but by the late 1800's they had become extremely rare in habitats below 900 m. Recently, however, populations of amakihi and apapane have been observed in low elevation habitats. We used twelve polymorphic microsatellite loci to investigate patterns of genetic structure, and to infer responses of these species to introduced avian malaria along an elevational gradient on the eastern flanks of Mauna Loa and Kilauea volcanoes on the island of Hawaii.</p> <p>Results</p> <p>Our results indicate that amakihi have genetically distinct, spatially structured populations that correspond with altitude. We detected very few apapane and no iiwi in low-elevation habitats, and genetic results reveal only minimal differentiation between populations at different altitudes in either of these species.</p> <p>Conclusion</p> <p>Our results suggest that amakihi populations in low elevation habitats have not been recolonized by individuals from mid or high elevation refuges. After generations of strong selection for pathogen resistance, these populations have rebounded and amakihi have become common in regions in which they were previously rare or absent.</p
    corecore