2,929 research outputs found

    Aspects of Neutrino Mass Matrices

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    After an Introduction briefly describing the rise and fall of the three-zero texture of the Zee model, we discuss still-allowed two-zero textures for the Majorana three-neutrino mass matrix. Finally, a model with two right-handed neutrinos and two Dirac texture zeros is described (FGY model) which can relate CP violation in leptogenesis to CP violation in long-baseline neutrino oscillations.Comment: 9 pages latex. Talk at Coral Gables 2003. Added reference

    Stability Issues for w < -1 Dark Energy

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    Precision cosmological data hint that a dark energy with equation of state w=P/ρ<1w = P/\rho < -1 and hence dubious stability is viable. Here we discuss for any ww nucleation from Λ>0\Lambda > 0 to Λ=0\Lambda = 0 in a first-order phase transition. The critical radius is argued to be at least of galactic size and the corresponding nucleation rate is glacial, thus underwriting the dark energy's stability and rendering remote any microscopic effect.Comment: 9 pages LaTeX. Significantly rewritten (including abstract

    Mersenne Primes, Polygonal Anomalies and String Theory Classification

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    It is pointed out that the Mersenne primes Mp=(2p1)M_p=(2^p-1) and associated perfect numbers Mp=2p1Mp{\cal M}_p=2^{p-1}M_p play a significant role in string theory; this observation may suggest a classification of consistent string theories.Comment: 10 pages LaTe

    German social pedagogy and social work: the academic discourses mapping a changing historical relationship

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    The term ‘social pedagogy’ was coined in Germany, a country which also provided fertile ground for the early development of social work. This article reconstructs the evolution of the two disciplines, which existed alongside one another for much of the twentieth century. It starts with their identities at the time of their early emergence, and then focuses on two formative periods: the early twentieth century, when both disciplines were in the nascent stages of independent development; and the late twentieth century, when they appeared to be in a state of amalgamation. In the course of this examination, Hämäläinen’s recent suggestion that social pedagogy can be regarded as a science, as a profession and in terms of its education is investigated. So too is Lorenz’s framework for considering a nation’s social professions in terms of social policy, civil society and academic discourse elements. Those academic discourses tied to the identity of the two professions offer an opportunity to pin down the slippery German concept of social pedagogy, demarcate it from social work and consider the path dependencies of each profession. This is carried out with particular reference to the early figures who shaped the disciplines, specifically Paul Natorp, Herman Nohl and Alice Salomon. The case of Germany reveals not only few uncontested definitions of the two professions, but also a clear formal separation for much of the twentieth century, which is best understood by considering historical, not contemporary arrangements

    Outcome from Spontaneous CP Violation for B Decays

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    In the aspon model solution of the strong CPCP problem, there is a gauged U(1)U(1) symmetry, spontaneously broken by the same vacuum expectation value which breaks CPCP, whose massive gauge boson provides an additional mechanism of weak CPCP violation. We calculate the CPCP asymmetries in BB decays for the aspon model and show that they are typically smaller than those predicted from the standard model. A linear relation between the CPCP asymmetries of different decay processes is obtained.Comment: REVTEX, 9 pages, IFP-486-UNC, NSF-PT-94-1, and UDHEP-01-9

    Aspects of Soft and Spontaneous CP Violation

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    We study four different models for CP violation: the standard (KM) model, the aspon model of spontaneous breaking and two models of soft breaking. In all except the standard model, the strong CP problem is addressed and solved. Testable predictions for the area of the unitarity triangle and for (epsilon'/epsilon)_K are emphasized. The issue of CP violation may well become the first place where the standard model of particle theory is shown definitively to be deficient. There are two reasons for expecting this to happen: (1) the strong CP problem is still not understood in the unadorned standard model and (2) the KM mechanism, although unquestionably present, may not provide the full explanation of epsilon_K and (epsilon'/epsilon)_K.Comment: 24 pages LaTeX including 4 figures. Minor modification to analysis of lower bound for d_n, summarized in new Table I

    Flavor Symmetry for Quarks and Leptons

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    Present data on neutrino masses and mixing favor the highly symmetric tribimaximal neutrino mixing matrix which suggests an underlying flavor symmetry. A systematic study of non-abelian finite groups of order g31g \leq 31 reveals that tribimaximal mixing can be derived not only from the well known tetrahedral flavor symmetry TA4T \equiv A_4, but also by using the binary tetrahedral symmetry TSL2(F3)T^{'} \equiv SL_2(F_3) which does not contain the tetrahedral group as a subgroup. TT^{'} has the further advantage that it can also neatly accommodate the quark masses including a heavy top quark.Comment: 12 pages latex. More typos correcte

    Constraints on Deflation from the Equation of State of Dark Energy

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    In cyclic cosmology based on phantom dark energy the requirement that our universe satisfy a CBE-condition ({\it Comes Back Empty}) imposes a lower bound on the number NcpN_{\rm cp} of causal patches which separate just prior to turnaround. This bound depends on the dark energy equation of state w=p/ρ=1ϕw = p/\rho = -1 - \phi with ϕ>0\phi > 0. More accurate measurement of ϕ\phi will constrain NcpN_{\rm cp}. The critical density ρc\rho_c in the model has a lower bound ρc(109GeV)4\rho_c \ge (10^9 {\rm GeV})^4 or ρc(1018GeV)4\rho_c \ge (10^{18} {\rm GeV})^4 when the smallest bound state has size 101510^{-15}m, or 103510^{-35}m, respectively.Comment: 23 pages, 3 figures, typos fixe
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