1,026 research outputs found
Port-Hamiltonian modeling for soft-finger manipulation
In this paper, we present a port-Hamiltonian model of a multi-fingered robotic hand, with soft-pads, while grasping and manipulating an object. The algebraic constraints of the interconnected systems are represented by a geometric object, called Dirac structure. This provides a powerful way to describe the non-contact to contact transition and contact viscoelasticity, by using the concepts of energy flows and power preserving interconnections. Using the port based model, an Intrinsically Passive Controller (IPC) is used to control the internal forces. Simulation results validate the model and demonstrate the effectiveness of the port-based approach
Impact of QED corrections to Higgs decay into four leptons at the LHC
At the LHC a precise measurement of the Higgs boson mass (if discovered), at
the level of 0.1-1%, will be possible through the channel g g --> H --> 4l for
a wide range of Higgs mass values. To match such an accuracy, the systematic
effects induced by QED corrections need to be investigated. In the present
study the calculation of O(alpha) and higher order QED corrections is
illustrated as well as their impact on the Higgs mass determination, once
realistic event selection criteria for charged leptons and photons are
considered.Comment: 5 pages, 5 figures, 1 table. Presented at HEP2005 July 21st-27th,
2005, Lisboa, Portugal and at RADCOR 2005, Shonan Village, October 2nd-7th,
2005, Japa
Photon pair production at flavour factories with per mille accuracy
We present a high-precision QED calculation, with 0.1% theoretical accuracy,
of two photon production in annihilation, as required by more and
more accurate luminosity monitoring at flavour factories. The accuracy of the
approach, which is based on the matching of exact next-to-leading order
corrections with a QED Parton Shower algorithm, is demonstrated through a
detailed analysis of the impact of the various sources of radiative corrections
to the experimentally relevant observables. The calculation is implemented in
the latest version of the event generator BabaYaga, available for precision
simulations of photon pair production at colliders of moderately high
energies.Comment: 11 pages, 5 figures, 1 tabl
The Electoral Consequences of Large Fiscal Adjustments
The conventional wisdom regarding the political consequences of large reductions of budget deficits is that they are very costly for the governments which implement them: they are punished by voters at the following elections. In the present paper, instead, we find no evidence that governments which quickly reduce budget deficits are systematically voted out of office in a sample of 19 OECD countries from 1975 to 2008. We also take into consideration issues of reverse causality, namely the possibility that only "strong and popular" governments can implement fiscal adjustments and thus they are not voted out of office "despite" having reduced the deficits. In the end we conclude that many governments can reduce deficits avoiding an electoral defeat.
Full one-loop electroweak corrections to e+e- to 3 jets at linear colliders
We describe the impact of the full one-loop electroweak terms of O(alpha_s
alpha_EM^3) entering the electron-positron into three-jet cross-section from
sqrt(s)=M_Z to TeV scale energies. We include both factorisable and
non-factorisable virtual corrections and photon bremsstrahlung. Their
importance for the measurement of alpha_S from jet rates and shape variables is
explained qualitatively and illustrated quantitatively, also in presence of
b-tagging.Comment: 6 pages, to appear in the proceedings of the workshop "LC09 -- e+e-
Physics at the TeV scale and the Dark Matter Connection", 21-24 September
2009, Perugia (Italy). Minor corrections, references added
Matrix elements and Parton Shower in the event generator BABAYAGA
A new version of the event generator BABAYAGA is presented, which is based on
an original matching of the Parton Shower approach with the complete exact
O(alpha) matrix element for the inclusion of the QED radiative corrections to
the Bhabha process at flavour factories. The theoretical accuracy of the
improved generator is conservatively estimated to be 0.2%, by comparison with
independent calculations. The generator is a useful tool for precise luminosity
determination at flavour factories, for center of mass energies below 10 GeV.Comment: 4 pages, 2 figures. To appear in the proceedings of the International
Workshop e+ e- Collisions from phi to psi, Novosibirsk (Russia), 27 Feb - 2
Mar 200
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