13,968 research outputs found

    The pentaquark in K-plus-d total cross section data

    Full text link
    An analysis of K+K^+-d total cross section data is undertaken to explore possible effects of the recently observed resonance in the S=+1 hadronic system with mass around 1.55 GeV. It is found that a structure corresponding to the resonance is visible in the data. The width consistent with the observed deviation from background is found to be 0.9±0.30.9\pm 0.3 MeV and the mass is 1.559±0.0031.559\pm 0.003 GeV/c2^2 for spin-parity \h^+ and 1.547±0.0021.547\pm0.002\ GeV/c2^2 for \h^-. The errors are one standard deviation and statistical only. \Comment: 10 pages, 5 figures Replaced to correct references, add and correct text. No change in content. More discussion of errors, increased error on width, corrected one figur

    Origin and evolution of the Amazonian craton

    Get PDF
    The Amazonian craton appears to be formed and modifed by processes much like those of the better-known Precambrian cratons, but the major events did not always follow conventional sequences nor did they occur synchronously with those of other cratons. Much of the craton's Archean style continental crust formation, recorded in granite-greenstone and high-grade terranes, occurred in the Early Proterozoic: a period of relative quiescence in many other Precambrian regions. The common Archean to Proterozoic transition in geological style did not occur here, but an analogous change from abundant marine volcanism to dominantly continental sedimentary and eruptive styles occurred later. Amazonian geology is summarized, explaining the evolution of the craton

    Monte Carlo simulation of baryon and lepton number violating processes at high energies

    Get PDF
    We report results obtained with the first complete event generator for electroweak baryon and lepton number violating interactions at supercolliders. We find that baryon number violation would be very difficult to establish, but lepton number violation can be seen provided at least a few hundred L violating events are available with good electron or muon identification in the energy range 10 GeV to 1 TeV.Comment: 40 Pages uuencoded LaTeX (20 PostScript figures included), Cavendish-HEP-93/6, CERN-TH.7090/9

    Pion double charge exchange on 4He

    Get PDF
    The doubly differential cross sections for the 4^4He(π+,π)4p(\pi^+,\pi^-) 4p reaction were calculated using both a two-nucleon sequential single charge exchange model and an intranuclear cascade code. Final state interactions between the two final protons which were the initial neutrons were included in both methods. At incident pion energies of 240 and 270 MeV the low-energy peak observed experimentally in the energy spectrum of the final pions can be understood only if the contribution of pion production is included. The calculated cross sections are compared with data.Comment: 25 pages, 9 figure

    Pathways to Parenting in New Zealand: Issues in Law, Policy and Practice

    Get PDF
    In New Zealand there are many ways to become a parent, including two-parent families of heterosexual and homosexual couples, single parents, adoptive parents, kin carers, wha ̄ngai arrangements, long-term fostering, guardianship and assisted reproductive technologies. In this paper we discuss the different pathways to parenthood, how they have come about, and New Zealand’s laws, policies and practices that make them possible but also challenging. Two areas of law of particular interest are the implications of the Adoption Act 1955, which continues to be discriminatory, although some of its provisions have been reinterpreted in the courts, and the Care of Children Act 2004, which introduced ‘modern’ parenting arrangements but allowed conflicts to remain with previous child care Acts. The new Home for Life policy introduced by the Ministry of Social Development will also be critically discussed, in light of its weaknesses. We conclude with implications of the varied pathways and identified gaps in our current knowledge that call for further research

    An intermediate state between the kagome-ice and the fully polarized state in Dy2_2Ti2_2O7_7

    Get PDF
    Dy2_2Ti2_2O7_7 is at present the cleanest example of a spin-ice material. Previous theoretical and experimental work on the first-order transition between the kagome-ice and the fully polarized state has been taken as a validation for the dipolar spin-ice model. Here we investigate in further depth this phase transition using ac-susceptibility and dc-magnetization, and compare this results with Monte-Carlo simulations and previous magnetization and specific heat measurements. We find signatures of an intermediate state between the kagome-ice and full polarization. This signatures are absent in current theoretical models used to describe spin-ice materials.Comment: 7 pages, 4 figure

    The photon blockade effect in optomechanical systems

    Full text link
    We analyze the photon statistics of a weakly driven optomechanical system and discuss the effect of photon blockade under single photon strong coupling conditions. We present an intuitive interpretation of this effect in terms of displaced oscillator states and derive analytic expressions for the cavity excitation spectrum and the two photon correlation function g(2)(0)g^{(2)}(0). Our results predict the appearance of non-classical photon correlations in the combined strong coupling and sideband resolved regime, and provide a first detailed understanding of photon-photon interactions in strong coupling optomechanics

    Convex Functions and Spacetime Geometry

    Full text link
    Convexity and convex functions play an important role in theoretical physics. To initiate a study of the possible uses of convex functions in General Relativity, we discuss the consequences of a spacetime (M,gμν)(M,g_{\mu \nu}) or an initial data set (Σ,hij,Kij)(\Sigma, h_{ij}, K_{ij}) admitting a suitably defined convex function. We show how the existence of a convex function on a spacetime places restrictions on the properties of the spacetime geometry.Comment: 26 pages, latex, 7 figures, improved version. some claims removed, references adde
    corecore