Naturalness

About: Naturalness is a research topic. Over the lifetime, 1305 publications have been published within this topic receiving 31737 citations.

Hide and Seek With Natural Supersymmetry at the LHC

Abstract: Gluinos that result in classic large missing transverse momentum signatures at the LHC have been excluded by 2011 searches if they are lighter than around 800 GeV. This adds to the tension between experiment and supersymmetric solutions of the naturalness problem, since the gluino is required to be light if the electroweak scale is to be natural. Here, we examine natural scenarios where supersymmetry is present, but was hidden from 2011 searches due to violation of R-parity and the absence of a large missing transverse momentum signature. Naturalness suggests that third generation states should dominate gluino decays and we argue that this leads to a generic signature in the form of same-sign, flavour-ambivalent leptons, without large missing transverse momentum. As a result, searches in this channel are able to cover a broad range of scenarios with some generality and one should seek gluinos that decay in this way with masses below a TeV. We encourage the LHC experiments to tailor a search for supersymmetry in this form. We consider a specific case that is good at hiding: baryon number violation, and estimate that the most constraining existing search from 2011 data implies a lower bound on the gluino mass of 550 GeV.

Naturalness and markedness

Abstract: The following comparison of Naturalness theory and Markedness theory contrasts naturalness scales and markedness relations and the distinct notions of value in the two theories in order to focus on recent advances in the identification of rules of naturalness syntax and markedness syntax. It is shown that whereas naturalness theory offers little basis for accounts of variation and change, key notions in markedness theory play a central role both in accounts of synchronic variation and in explanations of the initiation and actualization of change. In a concluding comparison of the two theories it is argued that Markedness theory in essential respects subsumes Naturalness theory. This explains why many linguists find the two theories kindred, and it suggests that the future will see their unification.

Is F-term hybrid inflation natural within minimal supersymmetric SO(10)?

Abstract: We examine whether F-term supersymmetric hybrid inflation can in a natural way be embedded within the minimal SO(10) model. We show that none of the sin- glets of the Standard Model symmetries in the minimal set of SO(10) representations can satisfy the conditions which are necessary for a scalar field to play the role of the inflaton. As a consequence, one has to introduce an extra scalar field, which, however, may spoil the naturalness of inflation within the context of SO(10). Nevertheless, if we add an extra scalar field, we are then able to construct a model that can accom- modate flat directions, while it preserves the stability of the inflationary valley.

Triplet-extended scalar sector and the naturalness problem

Abstract: We consider the extension of the Standard Model by a complex scalar triplet field, which occurs naturally in several models of leptogenesis and see-saw mechanism for neutrino mass generation, in the context of ameliorating the fine-tuning problem of the fundamental scalars through the Veltman Condition, i.e. by demanding the sum of the quadratically divergent corrections to vanish (or be at a reasonable level) by virtue of some possible symmetry of the underlying theory. We show that it is possible to cancel all the scalar one-loop quadratic divergences and hence obtain a viable solution for the fine-tuning problem, while satisfying the electroweak precision observables, including the $\rho$ parameter, and successfully generating the neutrino masses. The stability of the scalar potential puts important constraints on the model.