624 research outputs found
Spontaneous polarisation of the neutral interface for valence asymmetric coulombic systems
In this paper, we discuss the phenomenon of a spontaneous polarisation of a
neutral hard planar interface for valence asymmetric coulombic systems. Within
a field theoretical description, we account for the existence of non trivial
charge density and electric potential profiles. The analysis of the phenomenon
shows that the effect is related to combinatorics in relation with the
existence of the two independent species cations and anions. This simple and
basic feature is related to the quantum mechanical properties of the system.
The theoretical results are compared with numerical simulations data and are
shown to be in very good agreement, which a fortiori justifies our physical
interpretation.Comment: 12 pages, 11 figure
Higher-order scalar interactions and SM vacuum stability
Investigation of the structure of the Standard Model effective potential at
very large field strengths opens a window towards new phenomena and can reveal
properties of the UV completion of the SM. The map of the lifetimes of the
vacua of the SM enhanced by nonrenormalizable scalar couplings has been
compiled to show how new interactions modify stability of the electroweak
vacuum. Whereas it is possible to stabilize the SM by adding Planck scale
suppressed interactions and taking into account running of the new couplings,
the generic effect is shortening the lifetime and hence further destabilisation
of the SM electroweak vacuum. These findings have been illustrated with phase
diagrams of modified SM-like models. It has been demonstrated that
stabilisation can be achieved by lowering the suppression scale of higher order
operators while picking up such combinations of new couplings, which do not
deepen the new minima of the potential. Our results show the dependence of the
lifetime of the electroweak minimum on the magnitude of the new couplings,
including cases with very small couplings (which means very large effective
suppression scale) and couplings vastly different in magnitude (which
corresponds to two different suppression scales).Comment: plain Latex, 9 figure
F-term uplifting via consistent D-terms
The issue of fine-tuning necessary to achieve satisfactory degree of
hierarchy between moduli masses, the gravitino mass and the scale of the
cosmological constant has been revisited in the context of supergravities with
consistent D-terms. We have studied (extended) racetrack models where
supersymmetry breaking and moduli stabilisation cannot be separated from each
other. We show that even in such cases the realistic hierarchy can be achieved
on the expense of a single fine-tuning. The presence of two condensates changes
the role of the constant term in the superpotential, W_0, and solutions with
small vacuum energy and large gravitino mass can be found even for very small
values of W_0. Models where D-terms are allowed to vanish at finite vevs of
moduli fields - denoted `cancellable' D-terms - and the ones where D-terms may
vanish only at infinite vevs of some moduli - denoted `non-cancellable' -
differ markedly in their properties. It turns out that the tuning with respect
to the Planck scale required in the case of cancellable D-terms is much weaker
than in the case of non-cancellable ones. We have shown that, against
intuition, a vanishing D-term can trigger F-term uplifting of the vacuum energy
due to the stringent constraint it imposes on vacuum expectation values of
charged fields. Finally we note that our models only rely on two dimensionful
parameters: M_P and W_0.Comment: 10 pages, 2 figures, plain Latex, references adde
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Mobile/portable transuranic waste characterization systems at Los Alamos National Laboratory and a model for their use complex-wide
Los Alamos National Laboratory (LANL) has implemented mobile and portable characterization and repackaging systems to characterize transuranic (TRU) waste in storage for ultimate shipment and disposal at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. These mobile systems are being used to characterize and repackage waste to meet the full requirements of the WIPP Waste Acceptance Criteria (WAC) and the WIPP Characterization Quality Assurance Program Plan (QAPP). Mobile and portable characterization and repackaging systems are being used to supplement the capabilities and throughputs of existing facilities. Utilization of mobile systems is a key factor that is enabling LANL to (1) reduce its TRU waste work-off schedule from 36 years to 8.5 years; (2) eliminate the need to construct a 200M. Aggressive implementation of mobile and portable systems throughout the Department of Energy complex through a centralized-distributed services model will result in similar advantages complex-wide
Recommended from our members
Mobile/portable transuranic waste characterization systems at Los Alamos National Laboratory and a model for their use complex-wide
Los Alamos National Laboratory has implemented mobile and portable characterization and repackaging systems to characterize TRU waste in storage for ultimate shipment and disposal at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. These mobile systems are being used to characterize and repackage waste to meet the full requirements of the WIPP Waste Acceptance Criteria (WAC) and the WIPP Characterization Quality Assurance Program Plan (QAPP). Mobile and portable characterization and repackaging systems are being used to supplement the capabilities and throughputs of existing facilities. Utilization of mobile systems is a key factor that is enabling LANL to: (1) reduce its TRU waste work-off schedule from 36 years to 8.5 years; (2) eliminate the need to construct a 200M. Aggressive implementation of mobile and portable systems throughout the DOE complex through a centralized-distributed services model will result in similar advantages complex-wide
Universal Constraints on Low-Energy Flavour Models
It is pointed out that in a general class of flavour models one can identify
certain universally present FCNC operators, induced by the exchange of heavy
flavour messengers. Their coefficients depend on the rotation angles that
connect flavour and fermion mass basis. The lower bounds on the messenger scale
are derived using updated experimental constraints on the FCNC operators. The
obtained bounds are different for different operators and in addition they
depend on the chosen set of rotations. Given the sensitivity expected in the
forthcoming experiments, the present analysis suggests interesting room for
discovering new physics. As the highlights emerge the leptonic processes,
, and
conversion in nuclei.Comment: 18 pages, 3 figures; v2 matches published versio
The Messenger Sector of SUSY Flavour Models and Radiative Breaking of Flavour Universality
The flavour messenger sectors and their impact on the soft SUSY breaking
terms are investigated in SUSY flavour models. In the case when the flavour
scale M is below the SUSY breaking mediation scale M_S, the universality of
soft terms, even if assumed at M_S, is radiatively broken. We estimate this
effect in a broad class of models. In the CKM basis that effect gives flavour
off-diagonal soft masses comparable to the tree-level estimate based on the
flavour symmetry.Comment: 24 pages, 3 figures. v3: minor changes in the text, typos corrected,
version accepted for publication in JHE
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