14,660 research outputs found
Renormalization Group Running of Dimension-Six Sources of Parity and Time-Reversal Violation
We perform a systematic study of flavor-diagonal parity- and
time-reversal-violating operators of dimension six which could arise from
physics beyond the SM. We begin at the unknown high-energy scale where these
operators originate. At this scale the operators are constrained by gauge
invariance which has important consequences for the form of effective operators
at lower energies. In particular for the four-quark operators. We calculate
one-loop QCD and, when necessary, electroweak corrections to the operators and
evolve them down to the electroweak scale and subsequently to hadronic scales.
We find that for most operators QCD corrections are not particularly
significant. We derive a set of operators at low energy which is expected to
dominate hadronic and nuclear EDMs due to physics beyond the SM and obtain
quantitative relations between these operators and the original dimension-six
operators at the high-energy scale. We use the limit on the neutron EDM to set
bounds on the dimension-six operators.Comment: Matches published version, 35 pages, 6 figures, minor correction
Evaluation of the impact of low versus high resolution data on nitrous oxide emissions from a rural landscape
We compared N2O emission results of the simple process based model INITIATOR, using landscape scale data, national scale data and European scale data. All three methods where applied to the Noordelijke Friese Wouden. Abstract about a research project
The phenomenology of electric dipole moments in models of scalar leptoquarks
We study the phenomenology of electric dipole moments (EDMs) induced in
various scalar leptoquark models. We consider generic leptoquark couplings to
quarks and leptons and match to Standard Model effective field theory. After
evolving the resulting operators to low energies, we connect to EDM experiments
by using up-to-date hadronic, nuclear, and atomic matrix elements. We show that
current experimental limits set strong constraints on the possible CP-violating
phases in leptoquark models. Depending on the quarks and leptons involved in
the interaction, the existing searches for EDMs of leptons, nucleons, atoms,
and molecules all play a role in constraining the CP-violating couplings. We
discuss the impact of hadronic and nuclear uncertainties as well as the
sensitivities that can be achieved with future EDM experiments. Finally, we
study the impact of EDM constraints on a specific leptoquark model that can
explain the recent -physics anomalies.Comment: Published versio
Persistence of the valence bond glass state in the double perovskites Ba2-xSrxYMoO6
Peer reviewedPublisher PD
Right-handed charged currents in the era of the Large Hadron Collider
We discuss the phenomenology of right-handed charged currents in the
framework of the Standard Model Effective Field Theory, in which they arise due
to a single gauge-invariant dimension-six operator. We study the manifestations
of the nine complex couplings of the to right-handed quarks in collider
physics, flavor physics, and low-energy precision measurements. We first obtain
constraints on the couplings under the assumption that the right-handed
operator is the dominant correction to the Standard Model at observable
energies. We subsequently study the impact of degeneracies with other
Beyond-the-Standard-Model effective interactions and identify observables, both
at colliders and low-energy experiments, that would uniquely point to
right-handed charged currents.Comment: 50 pages plus appendices and reference
Environmental monitoring in heterogeneous soil-landscapes; A Dutch case study
The spatial heterogeneity of agricultural soil-landscapes is mostly not taken into account in environmental policies. Most environmental goals have been defined at national level or farm level but not at the landscape level. The potential for setting up a regional environmental monitoring network that supports self governance was explored. The research was performed in the Northern Friesian Woodland
Neutrinoless double beta decay in chiral effective field theory: lepton number violation at dimension seven
We analyze neutrinoless double beta decay () within the
framework of the Standard Model Effective Field Theory. Apart from the
dimension-five Weinberg operator, the first contributions appear at dimension
seven. We classify the operators and evolve them to the electroweak scale,
where we match them to effective dimension-six, -seven, and -nine operators. In
the next step, after renormalization group evolution to the QCD scale, we
construct the chiral Lagrangian arising from these operators. We develop a
power-counting scheme and derive the two-nucleon currents up
to leading order in the power counting for each lepton-number-violating
operator. We argue that the leading-order contribution to the decay rate
depends on a relatively small number of nuclear matrix elements. We test our
power counting by comparing nuclear matrix elements obtained by various methods
and by different groups. We find that the power counting works well for nuclear
matrix elements calculated from a specific method, while, as in the case of
light Majorana neutrino exchange, the overall magnitude of the matrix elements
can differ by factors of two to three between methods. We calculate the
constraints that can be set on dimension-seven lepton-number-violating
operators from experiments and study the interplay between
dimension-five and -seven operators, discussing how dimension-seven
contributions affect the interpretation of in terms of the
effective Majorana mass .Comment: Matches version published in JHE
Combining economic and social goals in the design of production systems by using ergonomics standards
In designing of production systems, economic and social goals can be combined, if ergonomics is integrated into the design process. More than 50 years of ergonomics research and practice have resulted in a large number of ergonomics standards for designing physical and organizational work environments. This paper gives an overview of the 174 international ISO and European CEN standards in this field, and discusses their applicability in design processes. The available standards include general recommendations for integrating ergonomics into the design process, as well as specific requirements for manual handling, mental load, task design, human-computer-interaction, noise, heat, body measurements, and other topics. The standards can be used in different phases of the design process: allocation of system functions between humans and machines, design of the work organization, work tasks and jobs, design of work environment, design of work equipment, hardware and software, and design of workspace and workstation. The paper is meant to inform engineers and managers involved in the design of production systems about the existence of a large number of ISO and CEN standards on ergonomics, which can be used to optimize human well-being and overall system performance.review;standard;standardization;ergonomics;CEN;ISO;human factors;production engineering;production planning
- …