176 research outputs found

    Theory for polymer coils with necklaces of micelles

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    If many micelles adsorb onto the same polymer molecule then they are said to form a necklace. A minimal model of such a necklace is proposed and shown to be almost equivalent to a 1-dimensional fluid with nearest-neighbour interactions. The thermodynamic functions of this fluid are obtained and then used to predict the change in the critical micellar concentration of the surfactant in the presence of the polymer. If the amount of polymer is not too large there are two critical micellar concentrations, one for micelles in necklaces and one for free micelles.Comment: 12 pages, 5 figure

    The Muon Anomalous Magnetic Moment and the Standard Model

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    The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.Comment: Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory statu

    Vitamin-V: Virtual Environment and Tool-boxing for Trustworthy Development of RISC-V based Cloud Services

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    Vitamin-V is a 2023-2025 Horizon Europe project that aims to develop a complete RISC-V open-source software stack for cloud services with comparable performance to the cloud-dominant x86 counterpart and a powerful virtual execution environment for software development, validation, verification, and test that considers the relevant RISC-V ISA extensions for cloud deployment

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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    The spin precession frequency of muons stored in the (g2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaμ+ωaμ\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaμ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=(1.0±1.1)×1023b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mμdZ0+HXY)=(1.8±6.0×1023)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇμ+<1.4×1024\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇμ<2.6×1024\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    Final Report of the Muon E821 Anomalous Magnetic Moment Measurement at BNL

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    We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a_mu = (g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a_mu(Expt) = 11 659 208.0(5.4)(3.3) x 10^-10, where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a_mu includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, ~0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e+e- hadronic cross sections, lie 2.2 - 2.7 standard deviations below the experimental result.Comment: Summary paper of E821 Collaboration measurements of the muon anomalous magnetic moment, each reported earlier in Letters or Brief Reports; 96 pages, 41 figures, 16 tables. Revised version submitted to PR

    An Improved Limit on the Muon Electric Dipole Moment

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    Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.Comment: 19 pages, 15 figures, 7 table

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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    The spin precession frequency of muons stored in the (g2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaμ+ωaμ\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaμ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=(1.0±1.1)×1023b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mμdZ0+HXY)=(1.8±6.0×1023)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇμ+<1.4×1024\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇμ<2.6×1024\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    Climate and sustainability co-governance in Kenya: A multi-criteria analysis of stakeholders' perceptions and consensus

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    The Paris Agreement and the 2030 Agenda for Sustainable Development embody highly intertwined targets to act for climate in conjunction with sustainable development. This, however, entails different meanings and challenges across the world. Kenya, in particular, needs to address serious sustainability threats, like poverty and lack of modern and affordable energy access. This study uses a multi-criteria group decision aid and consensus measuring framework, to integrate both agendas, and engages with Kenyan stakeholders to help inform future mitigation research and policy in the country. Results showed that stakeholders highlight topics largely underrepresented in model-based mitigation analysis, such as biodiversity preservation and demand-side transformations, while pointing to gaps in cross-sectoral policies in relation to access to modern energy, agriculture, life on land, and climate change mitigation. With numerous past and recent policies aiming at these issues, persistent stakeholder concerns over these topics hint at limited success. Sectoral and technological priorities only recently emphasised in Kenyan policy efforts are also correlated with stakeholders' concerns, highlighting that progress is not only a matter of legislation, but also of coordination, consistency of targets, and comprehensibility. Higher bias is found among the preferences of stakeholders coming from the country's private sector. Results from this exercise can inform national policymakers on effectively reshaping the future direction of the country, as well as modelling efforts aimed at underpinning Kenya's energy, climate and sustainable development policy

    News from the Muon (g-2) Experiment at BNL

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    The magnetic moment anomaly a_mu = (g_mu - 2) / 2 of the positive muon has been measured at the Brookhaven Alternating Gradient Synchrotron with an uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees well with previous measurements. Standard Model evaluations currently differ from the experimental result by 1.6 to 3.0 standard deviations.Comment: Talk presented at RADCOR - Loops and Legs 2002, Kloster Banz, Germany, September 8-13 2002, to be published in Nuclear Physics B (Proc. Suppl.); 5 pages, 3 figure
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