arXiv subjects

David Curtin

Publications and source records attributed to David Curtin.

93 records · Page 6Linked to original sources

arXiv2010

SUSY-Yukawa Sum Rule at the LHC

We propose the "supersymmetric (SUSY) Yukawa sum rule", a relationship between physical masses and mixing angles of the third-generation quarks and squarks. The sum rule follows directly from a relation between quark and squark couplings to the Higgs, enforced by SUSY. It is exactly this relation that ensures the cancellation of the one-loop quadratic divergence in the Higgs mass from the top sector. Testing the sum rule experimentally would thus provide a powerful consistency check on SUSY as the solution to the gauge hierarchy problem. While such a test will most likely have to await a future next-generation lepton collider, the LHC experiments may be able to make significant progress towards this goal. If some of the terms entering the sum rule are measured at the LHC, the sum rule can be used (within SUSY framework) to put interesting constraints on the other terms, such as the mixing angles among third-generation squarks. We outline how the required mass measurements could be performed, and estimate the accuracy that can be achieved at the LHC.

hep-ph↗

arXiv2009

A Flavor Protection for Warped Higgsless Models

We examine various possibilities for realistic 5D higgsless models and construct a full quark sector featuring next-to-minimal flavor violation (with an exact bulk SU(2) protecting the first two generations) satisfying electroweak and flavor constraints. The "new custodially protected representation" is used for the third generation to protect the light quarks from flavor violations induced due to the heavy top. A combination of flavor symmetries, and RS-GIM for the right-handed quarks suppresses flavor-changing neutral currents below experimental bounds, assuming CKM-type mixing on the UV brane. In addition to the usual higgsless RS signals, this model predicts an exotic charge-5/3 quark with mass of about 0.5 TeV which should show up at the LHC very quickly, as well as nonzero flavor-changing neutral currents which could be detected in the next generation of flavor experiments. In the course of our analysis, we also find quantitative estimates for the errors of the fermion zero mode approximation, which are significant for higgsless-type models.

hep-ph↗

arXiv2006

Fermion Confinement in Brane World Models with SO(10) Unification

In this Honours Research Project the aim is to build a toy model of an SO(10) Grand Unified Theory with an extra spatial dimension. Utilising the Clash of Symmetries mechanism proposed for brane-world models by Davidson, Toner, Volkas and Wali and using the asymmetric kink solution for the Higgs Field in the 45 of SO(10) discovered by Shin and Volkas, the symmetry on the brane will be broken to SU(4) x SU(2) x U(1), whereas the symmetry in the bulk is G_SM x U(1). However, any fermions localised on the brane would experience slight leakage into the bulk, and hence the symmetry is broken down to G_SM x U(1). We then introduce different SO(10) representations for fermions into the theory and determine which components become localised as chiral zero-modes, in the hope that the Standard Model particles are confined. Various group theoretical techniques are introduced as we study the 120, 16, 126 and 144 representations, and detailed analysis of the 16's confinement characteristics is performed.

hep-ph↗