1,283 research outputs found
Surveying the SO(10) Model Landscape: The Left-Right Symmetric Case
Grand Unified Theories (GUTs) are a very well motivated extensions of the
Standard Model (SM), but the landscape of models and possibilities is
overwhelming, and different patterns can lead to rather distinct
phenomenologies. In this work we present a way to automatise the model building
process, by considering a top to bottom approach that constructs viable and
sensible theories from a small and controllable set of inputs at the high
scale. By providing a GUT scale symmetry group and the field content, possible
symmetry breaking paths are generated and checked for consistency, ensuring
anomaly cancellation, SM embedding and gauge coupling unification. We emphasise
the usefulness of this approach for the particular case of a non-supersymmetric
SO(10) model with an intermediate left-right symmetry and we analyse how
low-energy observables such as proton decay and lepton flavour violation might
affect the generated model landscape.Comment: 36 pages, 6 figure
EPICA ice core Dronning Maud Land: first results from stable isotope measurements back to the LGM
Reacting to anticipations: energy crises and energy policy in the 1970s ; an introduction
Changes in the energy sector cannot be
sufficiently described as reactions to past and present energy problems. Rather,
politicians and companies alike always react to the anticipation of future challenges.
Sharing this assumption, the articles in this HSR Special Issue reexamine
the energy crises of the 1970s. Their assessments broaden the temporal
and spatial scope of analysis and integrate various energy resources into
the picture, while examining how to situate the first and second oil crises within
the 1970s and the contemporary history of the industrialized world as a
whole
Reconciling the 2 TeV Excesses at the LHC in a Linear Seesaw Left-Right Model
We interpret the 2 TeV excesses at the LHC in a left-right symmetric model
with Higgs doublets and spontaneous -parity violation. The light neutrino
masses are understood via a linear seesaw, suppressed by a high -parity
breaking scale, and the heavy neutrinos have a pseudo-Dirac character. In
addition, with a suppressed right-handed gauge coupling
in an embedding, we can thereby interpret the observed excess
at CMS. We show that it can be reconciled with the diboson and dijet excesses
within a simplified scenario based on our model. Moreover, we find that the
mixing between the light and heavy neutrinos can be potentially large which
would induce dominant non-standard contributions to neutrinoless double beta
decay via long-range and neutrino exchange.Comment: References added, typos fixed, matches published version, 12 pages, 4
figure
(Machine) Learning from the COVID-19 Lockdown about Electricity Market Performance with a Large Share of Renewables
The negative demand shock due to the COVID-19 lockdown has reduced net demand
for electricity -- system demand less amount of energy produced by intermittent
renewables, hydroelectric units, and net imports -- that must be served by
controllable generation units. Under normal demand conditions, introducing
additional renewable generation capacity reduces net demand. Consequently, the
lockdown can provide insights about electricity market performance with a large
share of renewables. We find that although the lockdown reduced average
day-ahead prices in Italy by 45%, re-dispatch costs increased by 73%, both
relative to the average of the same magnitude for the same period in previous
years. We estimate a deep-learning model using data from 2017--2019 and find
that predicted re-dispatch costs during the lockdown period are only 26% higher
than the same period in previous years. We argue that the difference between
actual and predicted lockdown period re-dispatch costs is the result of
increased opportunities for suppliers with controllable units to exercise
market power in the re-dispatch market in these persistently low net demand
conditions. Our results imply that without grid investments and other
technologies to manage low net demand conditions, an increased share of
intermittent renewables is likely to increase costs of maintaining a reliable
grid
Searching for New Physics in Two-Neutrino Double Beta Decay
Motivated by non-zero neutrino masses and the possibility of New Physics
discovery, a number of experiments search for neutrinoless double beta decay.
While hunting for this hypothetical nuclear process, a significant amount of
two-neutrino double beta decay data has become available. Although these events
are regarded and studied mostly as the background of neutrinoless double beta
decay, they can be also used to probe physics beyond the Standard Model. In
this paper we show how the presence of right-handed leptonic currents would
affect the energy distribution and angular correlation of the outgoing
electrons in two-neutrino double beta decay. Consequently, we estimate
constraints imposed by currently available data on the existence of
right-handed neutrino interactions without having to assume their nature. In
this way our results complement the bounds coming from the non-observation of
neutrinoless double beta decay as they limit also the exotic interactions of
Dirac neutrinos. We perform a detailed calculation of two-neutrino double beta
decay under the presence of exotic (axial-)vector currents and we demonstrate
that current experimental searches can be competitive to existing limits.Comment: 28 pages, 6 figures, including appendi
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