22,831 research outputs found
and $K^+\rightarrow\pi^+\nu\bar{\nu} with NA62 at CERN SPS
Recent results a future prospects of the NA62 experiment at CERN SPS are
presented. The NA62 experiment performed the most precise measurement of the
ratio of the and K^+\rightarrow \mu^\pm\nuK^+\rightarrow\pi^+\nu\bar{\nu}K^+\rightarrow\pi^+\nu\bar{\nu}$ events in two years of data
taking, keeping the background at the level of 10%.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM
Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October
201
Contracting rigid germs in higher dimensions
Following Favre, we define a holomorphic germ f:(C^d,0) -> (C^d,0) to be
rigid if the union of the critical set of all iterates has simple normal
crossing singularities. We give a partial classification of contracting rigid
germs in arbitrary dimensions up to holomorphic conjugacy. Interestingly
enough, we find new resonance phenomena involving the differential of f and its
linear action on the fundamental group of the complement of the critical set.Comment: 30 pages, 0 figure
Reflections After Seattle
The WTO cannot operate in isolation from the concerns of the world in which it exists. Our ability to advance trade, build a stronger system, and move forward in a new round will hinge on our ability to make simultaneous progression on these issues. How do we do this? First, we must move toward a more collective leadership, one that reflects the reality of a multipolar world and especially the emergence of developing-country powers. Second, we need to look at the policy challenges we face as pieces of an interconnected puzzle. Third, we need a new forum for the management of these complex issues, one that is truly representative of the new global realities and that brings world leaders together to tackle an expanded policy agenda and the new challenges of globalization. Fourth, there is a need for a clear mandate from leaders to promote a common global strategy and common global actions
Sagnac Effect, Ring Lasers and Terrestrial Tests of Gravity
Light can be used as a probe to explore the structure of space-time: this is
usual in astrophysical and cosmological tests, however it has been recently
suggested that this can be done also in terrestrial laboratories. Namely, the
GINGER project aims at measuring post-Newtonian effects, such as the
gravito-magnetic ones, in an Earth based laboratory, by means of a ring lasers
array. Here, we first review the theoretical foundations of the Sagnac Effect,
on which ring lasers are based, and then we study the Sagnac Effect in a
terrestrial laboratory, emphasizing the origin of the gravitational
contributions that GINGER aims at measuring. Moreover, we show that accurate
measurements allow to set constraints on theories of gravity different from
General Relativity. Eventually, we describe the experimental setup of GINGER.Comment: 24 pages, 1 figure; accepted for publication in Galaxies, Special
Issue "Advances in Gravitational Research
Gravito-electromagnetic Effects of Massive Rings
The Einstein field equations in linear post-Newtonian approximation can be
written in analogy with electromagnetism, in the so-called
gravito-electromagnetic formalism. We use this analogy to study the
gravitational field of a massive ring: in particular, we consider a continuous
mass distribution on Keplerian orbit around a central body, and we work out the
gravitational field generated by this mass distribution in the intermediate
zone between the central body and the ring, focusing on the gravito-magnetic
component that originates from the rotation of the ring. In doing so, we
generalize and complement some previous results that focused on the purely
Newtonian effects of the ring (thus neglecting its rotation) or that were
applied to the case of rotating spherical shells. Eventually, we study in some
simple cases the effect of the the rotation of the ring, and suggest that, in
principle, this approach could be used to infer information about the angular
momentum of the ring.Comment: 13 pages, LaTeX, revised to match the version accepted for
publication in the International Journal of Modern Physics
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