arXiv subjects

Mark Goodsell

Publications and source records attributed to Mark Goodsell.

26 records · Page 2Linked to original sources

arXiv2011

Testing String Vacua in the Lab: From a Hidden CMB to Dark Forces in Flux Compactifications

We perform a detailed analysis of the phenomenological properties of hidden Abelian gauge bosons with a kinetic mixing with the ordinary photon within type IIB flux compactifications. We study the interplay between moduli stabilisation and the Green-Schwarz mechanism that gives mass to the hidden photon paying particular attention to the role of D-terms. We present two generic classes of explicit Calabi-Yau examples with an isotropic and an anisotropic shape of the extra dimensions showing how the last case turns out to be very promising to make contact with current experiments. In fact, anisotropic compactifications lead naturally to a GeV-scale hidden photon ("dark forces" that can be searched for in beam dump experiments) for an intermediate string scale; or even to an meV-scale hidden photon (which could lead to a "hidden CMB" and can be tested by light-shining-through-a-wall experiments) in the case of TeV-scale strings.

hep-th↗

arXiv2011

Easy Dirac Gauginos

A simple and natural model is presented that gives Dirac gauginos. The configuration is related to "deconstructed gaugino mediation". A high energy completion is provided based on existing ISS-like models of deconstructed gaugino mediation. This provides a complete picture of Dirac gauginos that includes the necessary extra adjoint fermions (generated as magnetic quarks of the ISS theory) and supersymmetry breaking (via the ISS mechanism). Moreover the screening of the scalar masses means that they can similar to or less than the gaugino masses, even though the supersymmetry breaking is driven by F-terms.

hep-th↗

arXiv2010

Anomaly Mediation in Superstring Theory

We study anomaly mediated supersymmetry breaking in type IIB string theory and use our results to test the supergravity formula for anomaly mediated gaugino masses. We compute 1-loop gaugino masses for models of D3-branes on orbifold singularities with 3-form fluxes by calculating the annulus correlator of 3-form flux and two gauginos in the zero momentum limit. Consistent with supergravity expectations we find both anomalous and running contributions to 1-loop gaugino masses. For background Neveu-Schwarz H-flux we find an exact match with the supergravity formula. For Ramond-Ramond flux there is an off-shell ambiguity that precludes a full matching. The anomaly mediated gaugino masses, while determined by the infrared spectrum, arise from an explicit sum over UV open string winding modes. We also calculate brane-to-brane tree-level gravity mediated gaugino masses and show that there are two contributions coming from the dilaton and from the twisted modes, which are suppressed by the full T^6 volume and the untwisted T^2 volume respectively.

hep-th↗

arXiv2010

One-loop Yukawa Couplings in Local Models

We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops.

hep-th↗

arXiv2010

Light hidden-sector U(1)s in string compactifications

We review the case for light U(1) gauge bosons in the hidden-sector of heterotic and type II string compactifications, present estimates of the size of their kinetic mixing with the visible-sector hypercharge U(1), and discuss their possibly very interesting phenomenological consequences in particle physics and cosmology.

hep-th↗

arXiv2009

Light Hidden U(1)s from String Theory

The possible masses and kinetic mixings of hidden U(1)s in the LARGE volume scenario are discussed, including the generalisation of the compact manifold to a K3 fibration.

hep-th↗

arXiv2009

Naturally Light Hidden Photons in LARGE Volume String Compactifications

Extra "hidden" U(1) gauge factors are a generic feature of string theory that is of particular phenomenological interest. They can kinetically mix with the Standard Model photon and are thereby accessible to a wide variety of astrophysical and cosmological observations and laboratory experiments. In this paper we investigate the masses and the kinetic mixing of hidden U(1)s in LARGE volume compactifications of string theory. We find that in these scenarios the hidden photons can be naturally light and that their kinetic mixing with the ordinary electromagnetic photon can be of a size interesting for near future experiments and observations.

hep-ph↗

arXiv2006

Noncommutativity from the string perspective: modification of gravity at a mm without mm sized extra dimensions

We explore how the IR pathologies of noncommutative field theory are resolved when the theory is realized as open strings in background B-fields: essentially, since the IR singularities are induced by UV/IR mixing, string theory brings them under control in much the same way as it does the UV singularities. We show that at intermediate scales (where the Seiberg-Witten limit is a good approximation) the theory reproduces the noncommutative field theory with all the (un)usual features such as UV/IR mixing, but that outside this regime, in the deep infra-red, the theory flows continuously to the commutative theory and normal Wilsonian behaviour is restored. The resulting low energy physics resembles normal commutative physics, but with additional suppressed Lorentz violating operators. We also show that the phenomenon of UV/IR mixing occurs for the graviton as well, with the result that, in configurations where Planck's constant receives a significant one-loop correction (for example brane-induced gravity), the distance scale below which gravity becomes non-Newtonian can be much greater than any compact dimensions.

hep-th↗