3,149 research outputs found

    Structure of Equilenin at 100 K: an estrone-related steroid

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    The structure of the estrone-related steroid, Equilenin, C18H18O2 (systematic name 3-hy-droxy-13-methyl-11,12,13,14,15,16-hexa-hydro-cyclo-penta-[a]phen-anthren-17-one), has been determined at 100 K. The crystals are ortho-rhom-bic, P212121, and the absolute structure of the mol-ecule in the crystal has been determined by resonant scattering [Flack parameter = -0.05 (4)]. The C atoms of the A and B rings are almost coplanar, with an r.m.s. deviation from planarity of 0.0104 Å. The C ring has a sofa conformation, while the D ring has an envelope conformation with the methine C atom as the flap. The keto O atom and the methyl group are translated 0.78 and 0.79 Å, respectively, from the equivalent positions on 17β-estrone. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming chains parallel to the c-axis direction

    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

    Conformality and Gauge Coupling Unification

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    It has been recently proposed to embed the standard model in a conformal gauge theory to resolve the hierarchy problem, and to avoid assuming either grand unification or low-energy supersymmetry. By model building based on string-field duality we show how to maintain the successful prediction of an electroweak mixing angle with sin2θ0.231sin^2\theta \simeq 0.231 in conformal gauge theories with three chiral families.Comment: 8 pages LaTe

    Natural fermion mass hierarchy and mixings in family unification

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    We present an SU(9) model of family unification with three light chiral families, and a natural hierarchy of charged fermion masses and mixings. The existence of singlet right handed neutrions with masses about two orders of magnitude smaller than the GUT scale, as needed to understand the light neutrinos masses via the see-saw mechanism, is compelling in our model.Comment: 7 pages, no figur

    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

    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

    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

    Axion and neutrino physics from anomaly cancellation

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    It has been recently shown that the requirement of anomaly cancellation in a (non-supersymmetric) six-dimensional version of the standard model fixes the field content to the known three generations. We discuss the phenomenological consequences of the cancellation of the local anomalies: the strong CP problem is solved and the fundamental scale of the theory is bounded by the physics of the axion. Neutrinos acquire a mass in the range suggested by atmospheric experiments.Comment: 9 pages, RevTeX

    Search for Heavy Leptons at Hadron Colliders

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    Four models are considered which contain heavy leptons beyond the three families of the standard model. Two are fourth-generation extensions of the standard model in which the right-handed heavy leptons are either isosinglets or in an isodoublet; the other two are motivated by the aspon model of CP violation. In all these models, the heavy neutrino can either be heavier than, or comparable in mass to, the charged lepton leading to the possibility that the charged lepton is very long-lived. Production cross section and signatures for the heavy leptons are computed for the SSC and LHC.Comment: 17 pages(8 figures are not included),TRI-PP-92-9

    3-3-1 exotic quark search at CERN LEPII-LHC

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    The 3-3-1 electroweak model is the simplest chiral extension of the standard model which predicts single and double charged bileptons and exotic quarks carrying -4/3 and 5/3 units of the positron charge. In this paper we study the possibilities of the production and decay of one of these exotic quarks at CERN LEPII-LHC collider. For typical vector bilepton, exotic quark masses and mixing angles we obtained between 20 and 750 events per year. Angular distributions are also presented.Comment: 5 pages, RevTex 3.1, 9 eps figures, to appear in Phys. Rev.
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