1,072 research outputs found
Isotropy of unitary involutions
We prove the so-called Unitary Isotropy Theorem, a result on isotropy of a
unitary involution. The analogous previously known results on isotropy of
orthogonal and symplectic involutions as well as on hyperbolicity of
orthogonal, symplectic, and unitary involutions are formal consequences of this
theorem. A component of the proof is a detailed study of the quasi-split
unitary grassmannians.Comment: final version, to appear in Acta Mat
On standard norm varieties
Let be a prime integer and a field of characteristic 0. Let be
the {\em norm variety} of a symbol in the Galois cohomology group
(for some ), constructed in the proof of
the Bloch-Kato conjecture. The main result of the paper affirms that the
function field has the following property: for any equidimensional
variety , the change of field homomorphism \CH(Y)\to\CH(Y_{F(X)}) of Chow
groups with coefficients in integers localized at is surjective in
codimensions . One of the main ingredients of the proof is a
computation of Chow groups of a (generalized) Rost motive (a variant of the
main result not relying on this is given in Appendix). Another important
ingredient is {\em -triviality} of , the property saying that the degree
homomorphism on \CH_0(X_L) is injective for any field extension with
. The proof involves the theory of rational correspondences
reviewed in Appendix.Comment: 38 pages; final version, to appear in Ann. Sci. \'Ec. Norm. Sup\'er.
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New Developments of EPOS 2
Since 2006, EPOS hadronic interaction model is being used for very high
energy cosmic ray analysis. Designed for minimum bias particle physics and used
for having a precise description of SPS and RHIC heavy ion collisions, EPOS
brought more detailed description of hadronic interactions in air shower
development. Thanks to this model it was possible to understand why there were
less muons in air shower simulations than observed in real data. With the start
of the LHC era, a better description of hard processes and collective effects
is needed to deeply understand the incoming data. We will describe the basic
physics in EPOS and the new developments and constraints which are taken into
account in EPOS 2.Comment: Contributed presentation to the XVI International Symposium on Very
High Energy Cosmic Ray Interactions (ISVHECRI 2010), Batavia, IL, USA (28
June 2 July 2010). 4 pages, 6 figure
Four-Valued Logics BD and DM4: Expansions
The paper discusses functional properties of some four-valued logics which are the expansions of four-valued Belnap’s logic DM4. At first, we consider the logics with two designated values, and then logics defined by matrices having the same underlying algebra, but with a different choice of designated values, i.e. with one designated value. In the preceding literature both approaches were developed independently. Moreover, we present the lattices of the functional expansions of DM4.Zadanie „ Wdrożenie platformy Open Journal System dla czasopisma „ Bulletin of the Section of Logic” finansowane w ramach umowy 948/P-DUN/2016 ze środków Ministra Nauki i Szkolnictwa Wyższego przeznaczonych na działalność upowszechniającą naukę
Jaśkowski's criterion and three-valued paraconsistent logics
A survey is given of three-valued paraconsistent propositional logics connected with Jaśkowski’s criterion for constructing paraconsistent logics. Several problems are raised and four new matrix three-valued paraconsistent logics are suggested
Global hyperon polarization at local thermodynamic equilibrium with vorticity, magnetic field and feed-down
The system created in ultrarelativistic nuclear collisions is known to behave
as an almost ideal liquid. In non-central collisions, due to the large orbital
momentum, such a system might be the fluid with the highest vorticity ever
created under laboratory conditions. Particles emerging from such a highly
vorticous fluid are expected to be globally polarized with their spins on
average pointing along the system angular momentum. Vorticity-induced
polarization is the same for particles and antiparticles, but the intense
magnetic field generated in these collisions may lead to the splitting in
polarization. In this paper we outline the thermal approach to the calculation
of the global polarization phenomenon for particles with spin and we discuss
the details of the experimental study of this phenomenon, estimating the effect
of feed-down. A general formula is derived for the polarization transfer in
two-body decays and, particularly, for strong and electromagnetic decays. We
find that accounting for such effects is crucial when extracting vorticity and
magnetic field from the experimental data.Comment: 14 pages, 1 figure. Final version published in PRC with one more
formula and slightly revised tex
Jets, Bulk Matter, and their Interaction in Heavy Ion Collisions at Several TeV
We discuss a theoretical scheme that accounts for bulk matter, jets, and the
interaction between the two. The aim is a complete description of particle
production at all transverse momentum () scales. In this picture, the
hard initial scatterings result in mainly longitudinal flux tubes, with
transversely moving pieces carrying the of the partons from hard
scatterings. These flux tubes constitute eventually both bulk matter (which
thermalizes and flows) and jets. We introduce a criterion based on parton
energy loss to decide whether a given string segment contributes to the bulk or
leaves the matter to end up as a jet of hadrons. Essentially low
segments from inside the volume will constitute the bulk, high segments
(or segments very close to the surface) contribute to the jets. The latter ones
appear after the usual flux tube breaking via q-qbar production (Schwinger
mechanism). Interesting is the transition region: Intermediate segments
produced inside the matter close to the surface but having enough energy to
escape, are supposed to pick up q-qbar pairs from the thermal matter rather
than creating them via the Schwinger mechanism. This represents a communication
between jets and the flowing bulk matter (fluid-jet interaction). Also very
important is the interaction between jet hadrons and the soft hadrons from the
fluid freeze-out. We employ the new picture to investigate Pb-Pb collisions at
2.76 TeV. We discuss the centrality and dependence of particle
production and long range dihadron correlations at small and large
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