16 research outputs found
750 GeV Diphoton excess from in F-theory GUTs
We interpret the 750-760 GeV diphoton resonance as one or more of the
spinless components of a singlet superfield arising from the three
27-dimensional representations of in F-theory, which also contain three
copies of colour-triplet charge vector-like fermions
and inert Higgs doublets to which the singlets may couple. For definiteness we
consider (without change) a model that was proposed some time ago which
contains such states, as well as bulk exotics, leading to gauge coupling
unification. The smoking gun prediction of the model is the existence of other
similar spinless resonances, possibly close in mass to 750-760 GeV, decaying
into diphotons, as well as the three families of vector-like fermions
.Comment: 15 pages, 5 figures, minor corrections, reference
R-Parity violation in F-Theory
We discuss R-parity violation (RPV) in semi-local and local F-theory
constructions. We first present a detailed analysis of all possible
combinations of RPV operators arising from semi-local F-theory spectral cover
constructions, assuming an GUT. We provide a classification of all
possible allowed combinations of RPV operators originating from operators of
the form , including the effect of fluxes
with global restrictions. We then relax the global constraints and perform
explicit computations of the bottom/tau and RPV Yukawa couplings, at an
local point of enhancement in the presence of general fluxes subject
only to local flux restrictions. We compare our results to the experimental
limits on each allowed RPV operator, and show that operators such as ,
and may be present separately within current bounds,
possibly on the edge of observability, suggesting lepton number violation or
neutron-antineutron oscillations could constrain F-theory models.Comment: 40 pages, 13 figures, minor correction
MSSM from F-theory SU(5) with Klein Monodromy
We revisit a class of SUSY GUT models which arise in the context of
the spectral cover with Klein Group monodromy . We show that
matter parities can be realised via new geometric symmetries respected by
the spectral cover. We discuss a particular example of this kind, where the low
energy effective theory below the GUT scale is just the MSSM with no exotics
and standard matter parity, extended by the seesaw mechanism with two
right-handed neutrinos
Processes of elite power and low-carbon pathways: experimentation, financialisation, and dispossession
What is a low-carbon pathway? To many, it is a way of mitigating climate change. To others, it is about addressing market failure or capturing the co-benefits attached to low-carbon systems, such as jobs or improved health. To still others, it represents building adaptive capacity and resilience in the face of climate change. However, these interpretations can fail to acknowledge how pathways of low-carbon transitions can also become intertwined with processes and structures of inequality, exclusion and injustice. Using a critical lens that draws from a variety of disciplines, this article explores three ways through which responses to climate change can entrench, exacerbate or reconfigure the power of elites. As society attempts to create a low-carbon society, including for example via coastal protection efforts, disaster recovery, or climate change mitigation and renewable energy, these efforts intersect with at least three processes of elite power: experimentation, financialisation, and dispossession. Experimentation is when elites use the world as a laboratory to test or pilot low-carbon technologies or policy models, transferring risks yet not always sharing benefits. Financialisation refers to the expansion and proliferation of finance, capital, and financial markets in the global economy and many national economies, processes of which have recently extended to renewable energy. Dispossession is when elites use decarbonisation as a process through which to appropriate land, wealth, or other assets (and in the process make society more majoritarian and/or unequal). We explore these three themes using a variety of evidence across illustrative case studies, including hard and soft coastal protection measures (Bangladesh, Netherlands), climate risk insurance (Malawi), and renewable energy auctions and associated processes of finance and investment (South Africa and Mexico)
Phenomenological implications of a minimal F-theory GUT with discrete symmetry
We discuss the origin of both non-Abelian discrete family symmetry and Abelian continuous family symmetry, as well as matter parity, from F-theory SUSY GUTs. We propose a minimal model based on the smallest GUT group , together with the non-Abelian family symmetry plus an Abelian family symmetry, where fluxes are responsible for doublet-triplet splitting, leading to a realistic low energy spectrum with phenomenologically acceptable quark and lepton masses and mixing. We show how a matter parity emerging from F-theory can suppress proton decay while allowing neutron-antineutron oscillations, providing a distinctive signature of the set-up
Discrete Family Symmetry from F-Theory GUTs
We consider realistic F-theory GUT models based on discrete family symmetries and , combined with GUT, comparing our results to existing field theory models based on these groups. We provide an explicit calculation to support the emergence of the family symmetry from the discrete monodromies arising in F-theory. We work within the spectral cover picture where in the present context the discrete symmetries are associated to monodromies among the roots of a five degree polynomial and hence constitute a subgroup of the permutation symmetry. We focus on the cases of and subgroups, motivated by successful phenomenological models interpreting the fermion mass hierarchy and in particular the neutrino data. More precisely, we study the implications on the effective field theories by analysing the relevant discriminants and the topological properties of the polynomial coefficients, while we propose a discrete version of the doublet-triplet splitting mechanism