44 research outputs found
Effects of a Real Singlet Scalar on Veltman Condition
We revisit the fine-tuning problem in the Standard Model (SM) and show the
modification in Veltman condition by virtue of a minimally-extended particle
spectrum with one real SM gauge singlet scalar field. We demand the new scalar
to interact with the SM fields through Higgs portal only, and that the new
singlet to acquire a vacuum expectation value, resulting in a mixing with the
CP-even neutral component of the Higgs doublet in the SM. The experimental
bounds on the mixing angle are determined by the observed best-fit signal
strength . While, the one-loop radiative corrections to
the Higgs mass squared, computed with an ultraviolet cut-off scale ,
comes with a negative coefficient, the quantum corrections to the singlet mass
squared acquires both positive and negative values depending on the parameter
space chosen, which if positive might be eliminated by introducing singlet or
doublet vector-like fermions. However, based upon the fact that there is mixing
between the scalars, when transformed into the physical states, the tree-level
coupling of the Higgs field to the vector-like fermions worsen the Higgs mass
hierarchy problem. Therefore, the common attempt to introduce vector-like
fermions to cancel the divergences in the new scalar mass, might not be a
solution, if there is mixing between the scalars.Comment: 6pp, 3 figs, accepted for publication in Physics Letters
Relativistic MOND from Modified Energetics
We begin to investigate the question of what modifications in energy-momentum
tensor can yield correct MOND regime. As a starting study, we refrain from
insisting on an action principle and focus exclusively on the equations of
motion. The present work, despite the absence of an explicit action functional,
can be regarded to extend Milgrom's modified inertia approach to relativistic
domain. Our results show that a proper MOND limit arises if energy-momentum
tensor is modified to involve determinant of the metric tensor in reference to
the flat metric, where the latter is dynamically generated as in gravitational
Higgs mechanism. This modified energy-momentum tensor is conserved in both
Newtonian and MONDian regimes.Comment: 7p
Higgsed Stueckelberg Vector and Higgs Quadratic Divergence
Here we show that, a hidden vector field whose gauge invariance is ensured by
a Stueckelberg scalar and whose mass is spontaneously generated by the Standard
Model Higgs field contributes to quadratic divergences in the Higgs boson mass
squared, and even leads to its cancellation at one-loop when Higgs coupling to
gauge field is fine-tuned. In contrast to mechanisms based on hidden scalars
where a complete cancellation cannot be achieved, stabilization here is
complete in that the hidden vector and the accompanying Stueckelberg scalar are
both free from quadratic divergences at one-loop. This stability, deriving from
hidden exact gauge invariance, can have important implications for modelling
dark phenomena like dark matter, dark energy, dark photon and neutrino masses.
The hidden fields can be produced at the LHC.Comment: 5pp, 1 fig. Improved exposition, rectified concurrency to broken and
unbroken electroweak vacua, added reference
Hidden Spin-3/2 Field in the Standard Model
Here we show that a massive spin-3/2 field can hide in the SM spectrum in a
way revealing itself only virtually. We study collider signatures and loop
effects of this field, and determine its role in Higgs inflation and its
potential as Dark Matter. We show that this spin-3/2 field has a rich linear
collider phenomenology and motivates consideration of a neutrino-Higgs
collider. We also show that study of Higgs inflation, dark matter and dark
energy can reveal more about the neutrino and dark sector.Comment: 8 pages, 8 figures, accepted for publication in Eur. Phys. J.
Stakeholders’ views on improving the organic certification system: Results from an EU level workshop
The FP7 CERTCOST project has the overall objective to give recommendations to the public authorities and private actors in the whole organic certification chain on how to improve the organic food certification systems in terms of efficiency, transparency and cost effectiveness. According to the project description (the Description of Work, or DoW) this will be done based on a scientific economic in depth analysis of the certification systems from the farmer to the consumer in 5 EU countries (the Czech Republic, Denmark, Germany, Italy and the United Kingdom), plus Switzerland and the candidate country, Turkey. To safeguard that the CERTCOST objectives, work plan and methodology is in line with the expectations of key stakeholders from all levels of the certification chain the DoW foresaw a Stakeholder workshop to be organised in the beginning of the project.
The current report documents the main points of the discussions and recommendation given by the stakeholders at this CERTCOST Stakeholder workshop, which took place on November, 13-15, 2008 in Izmir, Turkey, 2.5 months after the project had started.
A total of 20 stakeholders were invited, of whom 16 could participate in the workshop. The participant profile included both users and providers of the certification system at different levels such as representatives of farmers’ organizations certification/control bodies, government authorities, EU Commission, processors/ traders, private experts/consultants. Together with the representatives of the partner institutions in the CERTCOST project, the total number of workshop participants was 35 representing 12 European countries.
Given the diverse backgrounds of the workshop participants, a working group approach (World Café approach) was applied in order to give the participants the opportunity to reflect their experiences and ideas on the implementation of the project in a synergetic, comfortable and free environment.
After a brief presentation of the project, outlining the tasks of the work packages and describing the proposed links between the project and the stakeholders by the project coordinator, the stakeholders were divided into four groups according to their level in the organic certification chain, as farmers, processors/traders, certification bodies and consumers. Two working group sessions were carried out around the questions provided to the stakeholders before the workshop through electronic mails. The questions had been compiled based on input from the managers of the four work packages which were relevant to the workshop discussion. After the first working group session, a plenary discussion session for clustering of the output given by the working groups, their validation and assessment was carried out. In the second session of the working groups, it was rather aimed to harmonize the understanding between the diversified opinions mentioned in Session 1.
The working group approach concluded in a final plenary discussion. On the second day, the CERTCOST work package managers presented how the discussions, comments and inputs of the working group sessions could impact on their working plans. In the final session the stakeholders were addressed directly for providing further ideas both on the project and on future collaboration options.
The workshop was strongly focused on the identification of key characteristics of cost factors along the supply chain in relation to their impact on the quality of the given service. However a broad range of related subjects were discussed.
The Stakeholder workshop put forward that, the ‘cost’ was among the most important topics relating to the certification system performance. The focus of the project aiming at cost effectiveness and not cost minimization was confirmed by the stakeholders. All of the stakeholders present in the workshop demonstrated elevated levels of interest on several outputs of the project. The workshop revealed very positive expectations among the stakeholders towards the risk based approach to be followed in the CERTCOST project. The detailed picture of the organic certification sector obtained through the workshop will constitute an important input to the CERTCOST project and the workshop is considered to be a successful first step in the project-stakeholder interaction.
The Stakeholder workshop provided important insight into the many discussion subjects of the organic certification systems in the EU and worldwide, among others the following should be mentioned. Farmers expect to have, clear rules, fair implementation, and high skilled guidance in the inspection and certification process, and underline the need for training of farmers and certifiers and for better communication between all parties in the certification chain. Processors point out the need for a good relationship with the inspectors and certifiers as well as the fact that there existed different schemes in different countries regarding the inspection process and the related cost structure. They also highlighted the difficulty of managing the relations with increasing number of different standards and different certification bodies. It is agreed that consumers expect something they can trust and they can easily recognize, a label, a logo, a certifier, a brand, a farmer or the word ‘organic’; at local, regional, national, or EU-level. It is also concluded that whether, why and how much some consumers might be willing to pay more for particular logos was unknown and was needed to be investigated.
Authorities/certification bodies stress that the issue of knowledge and education is extremely important and that there are complex legislations, no common standards, and differences within and between countries. They underline that there are different catalogues in different countries to deal with irregularities which should be harmonized. They emphasize that a clear definition of certification should be made covering its objectives, principles and tools.
While on some of the issues there has been a highlighted consensus among the groups, on some others contrasting ideas became evident. Among those subjects of absolute agreement were the importance of and the need for a more clear understanding of the certification system, its components and rules by all the parties involved. Education and elevated levels of necessary skills from farmer to inspector and to consumer; increased transparency and information exchange, well defined relationships between parties were considered to be an indispensable basis for a well functioning and more efficient certification system. The inspection concept came into prominence, with a discussion on policing vs. development approaches. While an efficient and comparable control system was judged to be crucial, promising private governmental formulations were agreed to be based on country conditions. Complexity of the legislation and lack of transparency were the remarkable barriers to a more efficient control system.
The EU logo and the new EU Regulation for organic certification were also discussed among stakeholders. It was suggested that the EU logo might have the potential to boost demand in the ‘less developed’ organic markets, but more promotion then currently planned would be needed. It was agreed that most consumers do not look for logos of particular standards but for the word ‘organic’ and/or an organic logo they are familiar with. This might be different for ‘committed’ organic consumers in more mature markets. Overall, it was agreed that ‘trust’ is the most crucial aspect of organic certification regarding the consumer side.
The issue of multiple certification and standards appeared to be a factor deserving more attention in the certification world. Harmonization in certification of the same characteristic of a product was deemed necessary. On the other hand, exchange of experiences and cooperation with markets like ‘Fair Trade’ was agreed to be potentially beneficial
Report on evaluation of the revision of council regulation (EEC) NO 2092/91, import regime in two exporting non-EU countries (TR, CH) and on an international level
This report provides an evaluation of the new EU import regulation for organic products (Council Regulation (EC) 834/2007, Commission Regulation (EC) No 1235/2008). To ensure that the evaluation addresses the issues and concerns of the stakeholders affected by the new import regulation and to increase the use of the evaluation results for upcoming decisions, this evaluation was organised as a stakeholder evaluation approach.
Based on the results from two national workshops in third countries (Turkey and Switzerland) and from one international workshop, the report concludes in policy recommendations to improve the import system for organic products as well as the organic sector as a whole
Electroweak Stability and Discovery Luminosities for New Physics
What is the luminosity needed for discovering new physics if the electroweak
scale is to remain stable? In this work we study this question, with the
example of a real singlet scalar which couples to the Higgs field already at
the renormalizable level. Observing that the electroweak scale remains stable
if the two scalars couple in a seesawic fashion, we show that the HL-LHC,
expected to deliver an integrated luminosity around 3/ab, can discover scalars
weighing up to 800 GeV. The FCC-hh, on the other hand, can discover scalars as
heavy as 2.3 TeV at 100/ab luminosity. It thus follows that the new physics
that does not destabilize the electroweak scale can be accessed only at high
luminosities, and is not possible exclude by the current LHC results.Comment: 14 pages, 14 figures, 5 tables; journal versio
The EU revised organic import regulation: What do the stakeholders think?
International Relations/Trade,
Scalars, Vectors and Tensors from Metric-Affine Gravity
The metric-affine gravity provides a useful framework for analyzing
gravitational dynamics since it treats metric tensor and affine connection as
fundamentally independent variables. In this work, we show that, a
metric-affine gravity theory composed of the invariants formed from
non-metricity, torsion and curvature tensors can be decomposed into a theory of
scalar, vector and tensor fields. These fields are natural candidates for the
ones needed by various cosmological and other phenomena. Indeed, we show that
the model accommodates TeVeS gravity (relativistic modified gravity theory),
vector inflation, and aether-like models. Detailed analyses of these and other
phenomena can lead to a standard metric-affine gravity model encoding scalars,
vectors and tensors.Comment: 13 p