1,706 research outputs found

    Status of the Solar Neutrino Puzzle

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    Using the latest results from the solar neutrino experiments and a few standard assumptions, I show that the popular solar models are ruled out at the 3σ\sigma level or at least TWO of the experiments are incorrect. Alternatively, one of the assumptions could be in error. These assumptions are spelled out in detail as well as how each one affects the argument.Comment: Latex, 8 pages + 4 uuencoded figures, minor changes made, FERMILAB-PUB/273-

    On the Coupling of Gravitons to Matter

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    Using relationships between open and closed strings, we present a construction of tree-level scattering amplitudes for gravitons minimally coupled to matter in terms of gauge theory partial amplitudes. In particular, we present examples of amplitudes with gravitons coupled to vectors or to a single fermion pair. We also present two examples with massive graviton exchange, as would arise in the presence of large compact dimensions. The gauge charges are represented by flavors of dynamical scalars or fermions. This also leads to an unconventional decomposition of color and kinematics in gauge theories.Comment: RevTex, 4 page

    On Perturbative Gravity and Gauge Theory

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    We review some applications of tree-level (classical) relations between gravity and gauge theory that follow from string theory. Together with DD-dimensional unitarity, these relations can be used to perturbatively quantize gravity theories, i.e. they contain the necessary information for obtaining loop contributions. We also review recent applications of these ideas showing that N=1 D=11 supergravity diverges, and review arguments that N=8 D=4 supergravity is less divergent than previously thought, though it does appear to diverge at five loops. Finally, we describe field variables for the Einstein-Hilbert Lagrangian that help clarify the perturbative relationship between gravity and gauge theory.Comment: Talk presented at Third Meeting on Constrained Dynamics and Quantum Gravity, Villasimius (Sardinia, Italy) September 13-17, 1999 and at the Workshop on Light-Cone QCD and Nonperturbative Hadron Physics, University of Adelaide (Australia) December 13-22, 1999. Latex, 9 page

    One-Loop NMHV Amplitudes involving Gluinos and Scalars in N=4 Gauge Theory

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    We use Supersymmetric Ward Identities and quadruple cuts to generate n-pt NMHV amplitudes involving gluinos and adjoint scalars from purely gluonic amplitudes. We present a set of factors that can be used to generate one-loop NMHV amplitudes involving gluinos or adjoint scalars in N=4 Super Yang-Mills from the corresponding purely gluonic amplitude.Comment: 16 pages, JHEP versio

    QCD Corrections to Spin Correlations in Top Quark Production at Lepton Colliders

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    Spin correlations, using a generic spin basis, are investigated to leading order in QCD for top quark production at lepton colliders. Even though, these radiative corrections induce an anomalous gamma/Z magnetic moment for the top quarks and allow for single, real gluon emission, their effects on the top quark spin orientation are very small. The final results are that the top (or anti-top) quarks are produced in an essentially unique spin configuration in polarized lepton collisions even after including the O(alpha_{s}) QCD corrections.Comment: 32 pages, REVTeX, 13 Postscript figures, psfig.sty and here.sty are required. Several references added, Tables 3, 4 and 5 are change

    The Complementarity of Eastern and Western Hemisphere Long-Baseline Neutrino Oscillation Experiments

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    We present a general formalism for extracting information on the fundamental parameters associated with neutrino masses and mixings from two or more long baseline neutrino oscillation experiments. This formalism is then applied to the current most likely experiments using neutrino beams from the Japan Hadron Facility (JHF) and Fermilab's NuMI beamline. Different combinations of muon neutrino or muon anti-neutrino running are considered. To extract the type of neutrino mass hierarchy we make use of the matter effect. Contrary to naive expectation, we find that both beams using neutrinos is more suitable for determining the hierarchy provided that the neutrino energy divided by baseline (E/LE/L) for NuMI is smaller than or equal to that of JHF. Whereas to determine the small mixing angle, θ13\theta_{13}, and the CP or T violating phase δ\delta, one neutrino and the other anti-neutrino is most suitable. We make extensive use of bi-probability diagrams for both understanding and extracting the physics involved in such comparisons.Comment: 21 pages, Latex, 3 postscript figure

    Identifying risk and mitigating gambling-related harm in online poker

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    The present paper conducts a critical analysis of the potential for gambling-related harm in relation to online poker participation, and a theoretical evaluation of current responsible gambling strategies employed to mitigate harm in online gambling and applies the evaluation of these strategies specifically to online poker gambling. Theoretically, the primary risk for harm in online poker is the rapid and continuous nature of poker provisions online, and has been demonstrated to be associated with disordered gambling behaviour, including the chasing of monetary losses. The following responsible gambling features were deemed relevant for consideration: informed player choice, voluntary self-exclusion, employee intervention, pre-commitment, in-game feedback, behavioural tracking tools, and age restriction and verification. Although current responsible gambling features are evaluated as theoretically robust, there remains a fundamental need for experimental validation of their effectiveness. Furthermore, despite online poker gamblers perceiving the responsible gambling features as valuable tools, in reality very few players regularly use available responsible gambling features. Ultimately, for the online poker gambling industry to retain market credibility and avoid substantial top-down regulation, it is imperative to demonstrate effectiveness of responsible gambling approaches, and increase customer utilisation of available harm-mitigation features

    Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments

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    In the overlap region, for the normal and inverted hierarchies, of the neutrino-antineutrino bi-probability space for νμνe\nu_\mu \to \nu_e appearance, we derive a simple identity between the solutions in the (sin22θ13\sin^2 2\theta_{13}, sinδ\sin \delta) plane for the different hierarchies. The parameter sin22θ13\sin^2 2\theta_{13} sets the scale of the νμνe\nu_\mu \to \nu_e appearance probabilities at the atmospheric δmatm22.4×103\delta m^2_{atm} \approx 2.4 \times 10^{-3} eV2^2 whereas sinδ\sin \delta controls the amount of CP violation in the lepton sector. The identity between the solutions is that the difference in the values of sinδ\sin \delta for the two hierarchies equals twice the value of sin22θ13\sqrt{\sin^2 2\theta_{13}} divided by the {\it critical} value of sin22θ13\sqrt{\sin^2 2\theta_{13}}. We apply this identity to the two proposed long baseline experiments, T2K and NOν\nuA, and we show how it can be used to provide a simple understanding of when and why fake solutions are excluded when two or more experiments are combined. The identity demonstrates the true complimentarity of T2K and NOν\nuA.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of Physics, ``Focus on Neutrino Physics'' issu
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