134 research outputs found
How research programs come apart: the example of supersymmetry and the disunity of physics
According to Peter Galison, the coordination of different ``subcultures''
within a scientific field happens through local exchanges within ``trading
zones''. In his view, the workability of such trading zones is not guaranteed,
and science is not necessarily driven towards further integration. In this
paper, we develop and apply quantitative methods (using semantic, authorship,
and citation data from scientific literature), inspired by Galison's framework,
to the case of the disunity of high-energy physics. We give prominence to
supersymmetry, a concept that has given rise to several major but distinct
research programs in the field, such as the formulation of a consistent theory
of quantum gravity or the search for new particles. We show that ``theory'' and
`phenomenology'' in high-energy physics should be regarded as distinct
theoretical subcultures, between which supersymmetry has helped sustain
scientific ``trades''. However, as we demonstrate using a topic model, the
phenomenological component of supersymmetry research has lost traction and the
ability of supersymmetry to tie these subcultures together is now compromised.
Our work supports that even fields with an initially strong sentiment of unity
may eventually generate diverging research programs and demonstrates the
fruitfulness of the notion of trading zones for informing quantitative
approaches to scientific pluralism
Lepton flavor violation beyond the MSSM
Most extensions of the Standard Model lepton sector predict large lepton
flavor violating rates. Given the promising experimental perspectives for
lepton flavor violation in the next few years, this generic expectation might
offer a powerful indirect probe to look for new physics. In this review we will
cover several aspects of lepton flavor violation in supersymmetric models
beyond the Minimal Supersymmetric Standard Model. In particular, we will
concentrate on three different scenarios: high-scale and low-scale seesaw
models as well as models with R-parity violation. We will see that in some
cases the LFV phenomenology can have characteristic features for specific
scenarios, implying that dedicated studies must be performed in order to
correctly understand the phenomenology in non-minimal supersymmetric models.Comment: 47 pages, 11 figures; v3: references added. Prepared for
"Supersymmetry beyond the NMSSM
A realistic model of neutrino masses with a large neutrinoless double beta decay rate
The minimal Standard Model extension with the Weinberg operator does
accommodate the observed neutrino masses and mixing, but predicts a
neutrinoless double beta () decay rate proportional to the
effective electron neutrino mass, which can be then arbitrarily small within
present experimental limits. However, in general decay can
have an independent origin and be near its present experimental bound; whereas
neutrino masses are generated radiatively, contributing negligibly to
decay. We provide a realization of this scenario in a simple,
well defined and testable model, with potential LHC effects and calculable
neutrino masses, whose two-loop expression we derive exactly. We also discuss
the connection of this model to others that have appeared in the literature,
and remark on the significant differences that result from various choices of
quantum number assignments and symmetry assumptions. In this type of models
lepton flavor violating rates are also preferred to be relatively large, at the
reach of foreseen experiments. Interestingly enough, in our model this stands
for a large third mixing angle, , when is required to lie below its present experimental limit.Comment: Published extended version with further reference
Phenomenology of the Neutrino-Mass-Giving Higgs Triplet and the Low-Energy Seesaw Violation of Lepton Number
Small realistic Majorana neutrino masses can be generated via a Higgs triplet
without having energy scales larger than TeV in the theory. The large effective mass scale in the
well-known seesaw neutrino-mass operator is
naturally obtained with where is a {\it small}
scale of lepton-number violation. In theories with large extra dimensions, the
smallness of is naturally obtained by the mechanism of ``shining'' if the
number of extra dimensions We study here the Higgs phenomenology of
this model, where the spontaneous violation of lepton number is treated as an
external source from extra dimensions. The observable decays will determine directly the magnitudes of the elements of
the neutrino mass matrix. The decays and ,
where is the massless Goldstone boson (Majoron), are also possible, but
of special importance is the decay which provides stringent
constraints on the allowed parameter space of this model. Based on the current
neutrino data, we also predict observable rates of conversion in
nuclei.Comment: Minor changes in the text, results unchange
- …