785 research outputs found
Electroweak Baryogenesis with Vector-like Leptons and Scalar Singlets
We investigate the viability of electroweak baryogenesis in a model with a
first order electroweak phase transition induced by the addition of two gauge
singlet scalars. A vector-like lepton doublet is introduced in order to provide
CP violating interactions with the singlets and Standard Model leptons, and the
asymmetry generation dynamics are examined using the vacuum expectation value
insertion approximation. We find that such a model is readily capable of
generating sufficient baryon asymmetry while satisfying electron electric
dipole moment and collider phenomenology constraints.Comment: 38 pages, 8 figures. Citations added. Benchmarks, figures and tables
updated, error fixed in calculations. Matches version published in JHE
New Signal of Atmospheric Tau Neutrino Appearance: Sub-GeV Neutral-Current Interactions in JUNO
We propose the first practical method to detect atmospheric tau neutrino
appearance at sub-GeV energies, which would be an important test of oscillations and of new-physics scenarios. In the
Jiangmen Underground Neutrino Observatory (JUNO; starts in 2024), active-flavor
neutrinos eject neutrons from carbon via neutral-current quasielastic
scattering. This produces a two-part signal: the prompt part is caused by the
scattering of the neutron in the scintillator, and the delayed part by its
radiative capture. Such events have been observed in KamLAND, but only in small
numbers and were treated as a background. With
oscillations, JUNO should measure a clean sample of 55 events/yr; with simple
disappearance, this would instead be 41 events/yr, where the latter
is determined from Super-Kamiokande charged-current measurements at similar
neutrino energies. Implementing this method will require precise laboratory
measurements of neutrino-nucleus cross sections or other developments. With
those, JUNO will have sensitivity to tau-neutrino appearance in 5
years exposure, and likely sooner.Comment: 12 pages, 8 figure
Interacting for the environment:Engaging Goffman in pro-environmental action
Whilst there are profound disagreements about how more sustainable forms of living might be achieved, most research on pro-environmental action recognises it as a fundamentally social challenge – demanding shifts not merely in individuals’ attitudes and behaviours, but also in social norms, contexts and practices. Despite the social nature of the challenge, perhaps the most fundamental social medium – social interaction - remains under-theorised in this area. To address this gap, this paper applies Erving Goffman’s understandings of social interaction to an ethnographic case study of a pro- environmental change initiative called Environment Champions. The analysis shows that social interaction plays a crucially important role in shaping responses to pro-environmental change processes that has the potential to both help and hinder the spread of pro-environmental action. The paper concludes by exploring how Goffman’s ideas develop and extend current debates about pro- environmental behaviour change
Two-Step Electroweak Symmetry-Breaking: Theory Meets Experiment
We study the phenomenology of a hypercharge-zero SU(2) triplet scalar whose
existence is motivated by two-step electroweak symmetry-breaking. We consider
both the possibility that the triplets are stable and contribute to the dark
matter density, or that they decay via mixing with the standard model Higgs
boson. The former is constrained by disappearing charged track searches at the
LHC and by dark matter direct detection experiments, while the latter is
constrained by existing multilepton collider searches. We find that a two-step
electroweak phase transition involving a stable triplet with a negative
quadratic term is ruled out by direct detection searches, while an unstable
triplet with a mass less than is excluded at
confidence level.Comment: 31 pages, 10 figures. Updated to match version published in JHE
A Real Triplet-Singlet Extended Standard Model: Dark Matter and Collider Phenomenology
We examine the collider and dark matter phenomenology of the Standard Model
extended by a hypercharge-zero SU(2) triplet scalar and gauge singlet scalar.
In particular, we study the scenario where the singlet and triplet are both
charged under a single symmetry. We find that such an extension
is capable of generating the observed dark matter density, while also modifying
the collider phenomenology such that the lower bound on the mass of the triplet
is smaller than in minimal triplet scalar extensions to the Standard Model. A
high triplet mass is in tension with the parameter space that leads to novel
electroweak phase transitions in the early universe. Therefore, the lower
triplet masses that are permitted in this extended model are of particular
importance for the prospects of successful electroweak baryogenesis and the
generation of gravitational waves from early universe phase transitions.Comment: 30 pages, 8 figures. Citations and related discussion adde
Two-step electroweak symmetry-breaking: theory meets experiment
We study the phenomenology of a hypercharge-zero SU (2) triplet scalar whose existence is motivated by two-step electroweak symmetry-breaking. We consider both the possibility that the triplets are stable and contribute to the dark matter density, or that they decay via mixing with the standard model Higgs boson. The former is constrained by disappearing charged track searches at the LHC and by dark matter direct detection experiments, while the latter is constrained by existing multilepton collider searches. We find that a two-step electroweak phase transition involving a stable triplet with a negative quadratic term is ruled out by direct detection searches, while an unstable triplet with a mass less than 230 GeV is excluded at 95% confidence level
An approach to describing and analysing bulk biological annotation quality: a case study using UniProtKB
Motivation: Annotations are a key feature of many biological databases, used
to convey our knowledge of a sequence to the reader. Ideally, annotations are
curated manually, however manual curation is costly, time consuming and
requires expert knowledge and training. Given these issues and the exponential
increase of data, many databases implement automated annotation pipelines in an
attempt to avoid un-annotated entries. Both manual and automated annotations
vary in quality between databases and annotators, making assessment of
annotation reliability problematic for users. The community lacks a generic
measure for determining annotation quality and correctness, which we look at
addressing within this article. Specifically we investigate word reuse within
bulk textual annotations and relate this to Zipf's Principle of Least Effort.
We use UniProt Knowledge Base (UniProtKB) as a case study to demonstrate this
approach since it allows us to compare annotation change, both over time and
between automated and manually curated annotations.
Results: By applying power-law distributions to word reuse in annotation, we
show clear trends in UniProtKB over time, which are consistent with existing
studies of quality on free text English. Further, we show a clear distinction
between manual and automated analysis and investigate cohorts of protein
records as they mature. These results suggest that this approach holds distinct
promise as a mechanism for judging annotation quality.
Availability: Source code is available at the authors website:
http://homepages.cs.ncl.ac.uk/m.j.bell1/annotation.
Contact: [email protected]: Paper accepted at The European Conference on Computational Biology
2012 (ECCB'12). Subsequently will be published in a special issue of the
journal Bioinformatics. Paper consists of 8 pages, made up of 5 figure
Unconventional PDV applications: detecting plasma and radiation
Author Institution: Sandia National LaboratoriesSlides presented at the 2018 Photonic Doppler Velocimetry (PDV) Users Workshop, Drury Plaza Hotel, Santa Fe, New Mexico, May 16-18, 2018
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