Alex Love

Constructing the supersymmetric Standard Model from intersecting D6-branes on the Z6′ orientifold

Abstract Intersecting stacks of supersymmetric fractional branes on the Z 6 ′ orientifold may be used to construct the supersymmetric Standard Model. If a , b are the stacks that generate the SU ( 3 ) colour and SU ( 2 ) L gauge particles, then, in order to obtain just the chiral spectrum of the (supersymmetric) Standard Model (with non-zero Yukawa couplings to the Higgs multiplets), it is necessary that the number of intersections a ∩ b of the stacks a and b, and the number of intersections a ∩ b ′ of a with the orientifold image b ′ of b satisfy ( a ∩ b , a ∩ b ′ ) = ( 2 , 1 ) or ( 1 , 2 ) . It is also necessary that there is no matter in symmetric representations of the gauge group, and not too much matter in antisymmetric representations, on either stack. Fractional branes having all of these properties may be constructed on the Z 6 ′ orientifold. We provide a number of new examples having these properties, some of which may be extended to give the Standard Model spectrum. Specifically, we construct four-stack models with two further stacks, each with just a single brane, which have the matter spectrum of the supersymmetric Standard Model, including a single pair of Higgs doublets, plus three right-chiral neutrino singlets. Ramond–Ramond tadpole cancellation is achieved by the introduction of background H ¯ 3 flux, the 3-form field strength associated with the Kalb–Ramond 2-form field B 2 . There remains a single unwanted gauged U ( 1 ) B − L .

Muon-proton scattering and the effect of neutral currents in the scaling region

Abstract We discuss the problem of testing weak-interaction models with the next generation of accelerators, and conclude that muon-proton scattering must be considered. The cross-sections for both polarised and umpolarised targets are obtained in the scaling region. The feasibility of detecting neutral weak currents is examined and optimum kinematical conditions to do this are found. Finally we suggest ways to isolate the neutral weak current.

Three triplet realisations of gauge models and deep inelastic scattering.

Abstract We investigate the predictions for very-high-energy inelastic neutrino scattering of three-triplet realisations of the weak-interaction gauge theories based on the groups O(3) and SU(2) × U(1).

Asymptotic near freedom

Abstract The possibility that the asymptotic behaviour of the structure functions for electroproduction or neutrinoproduction is controlled by a renormalisation group fixed point near the origin, but not at the origin, is discussed.

Intersecting D6-branes on the \( \mathbb{Z} \) 12-II orientifold

A bstractMuch work has been done by a number of authors with the aim of constructing the supersymmetric Standard Model in type IIA intersecting-brane theories compactified on an orientifold with various

Stabilising the supersymmetric Standard Model on the Z6′ orientifold

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Reduced modular symmetries of threshold corrections and gauge coupling unification

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Purely hadronic weak interactions in unified field theories of the weak and electromagnetic interactions

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Renormalization group fixed points in Yukawa theories

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Almost the supersymmetric Standard Model from the Z6′ orientifold

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