16 research outputs found

    Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector

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    The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure

    Inelastic Rescattering and CP Asymmetries in D -> pi+ pi-, pi0 pi0

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    We study the direct CP violation induced by inelastic final state interaction (FSI) rescattering in D→ππD\to\pi\pi modes, and find that the resultant CP asymmetry is about 10−410^{-4} which is larger than Ï”â€Č\epsilon' in the K-system. Our estimation is based on well-established theories and experiment measured data, so there are almost no free parameters except the weak phase ÎŽ13\delta_{13} in the CKM matrix.Comment: 9 page

    The Majorana project

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    Building a 0ÎœÎČ ÎČ experiment with the ability to probe neutrino mass in the inverted hierarchy region requires the combination of a large detector mass sensitive to 0ÎœÎČ ÎČ, on the order of 1-tonne, and unprecedented background levels, on the order of or less than 1 count per year in the 0ÎœÎČ ÎČ signal region. The Majorana Collaboration proposes a design based on using high-purity enriched 76Ge crystals deployed in ultra- low background electroformed Cu cryostats and using modern analysis techniques that should be capable of reaching the required sensitivity while also being scalable to a 1- tonne size. To demonstrate feasibility, the collaboration plans to construct a prototype system, the Majorana Demonstrator, consisting of 30 kg of 86% enriched 76Ge detectors and 30 kg of natural or isotope-76-depleted Ge detectors. We plan to deploy and evaluate two different Ge detector technologies, one based on a p-type configuration and the other on n-type

    Measurement of the CP-violating phase ÎČ\beta in B0→J/ψπ+π−B^0\rightarrow J/\psi \pi^+\pi^- decays and limits on penguin effects

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    Time-dependent CP violation is measured in the B0→J/ψπ+π−B^0\rightarrow J/\psi\pi^+\pi^- channel for each π+π−\pi^+\pi^- resonant final state using data collected with an integrated luminosity of 3.0 fb−1^{-1} in pppp collisions using the LHCb detector. The final state with the largest rate, J/ψρ0(770)J/\psi\rho^0(770), is used to measure the CP-violating angle 2ÎČeff2\beta^{\rm eff} to be (41.7±9.6−6.3+2.8)∘(41.7\pm 9.6_{-6.3}^{+2.8})^{\circ}. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, Bs0→J/ψϕB_s^0\rightarrow J/\psi\phi decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase ϕs\phi_s is limited to be within the interval [−1.05∘-1.05^\circ, +1.18∘1.18^\circ] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.Comment: 18 pages, 6 figures; v2-updated from reviewers comments and added a figur

    Active sites on enzymes of the shikimate pathway

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    SIGLEAvailable from British Library Document Supply Centre- DSC:D60756 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    The enzymatic basis for pesticide bioremediation

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    Enzymes are central to the biology of many pesticides, influencing their modes of action, environmental fates and mechanisms of target species resistance. Since the introduction of synthetic xenobiotic pesticides, enzymes responsible for pesticide turnover have evolved rapidly, in both the target organisms and incidentally exposed biota. Such enzymes are a source of significant biotechnological potential and form the basis of several bioremediation strategies intended to reduce the environmental impacts of pesticide residues. This review describes examples of enzymes possessing the major activities employed in the bioremediation of pesticide residues, and some of the strategies by which they are employed. In addition, several examples of specific achievements in enzyme engineering are considered, highlighting the growing trend in tailoring enzymatic activity to a specific biotechnologically relevant function
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