959 research outputs found
Elastic hadron scattering and optical theorem
All contemporary phenomenological models of elastic hadronic scattering have
been based in principle on the assumption of optical theorem validity that has
been overtaken from optics. It will be shown that the given theorem which has
not been actually proved in particle physics cannot be applied to short-ranged
strong interactions. The analysis of corresponding collision experiments is to
be done under new basic assumptions. The actual progress in description of
hadronic collision processes might then exist only if the initial states are
specified on the basis of impact parameter values of colliding particles and
probability dependence on this parameter is established, without limiting
corresponding conclusion by optical theorem validity.Comment: 11 pages, improved text to emphasize invalidity of optical theorem in
short-ranged hadronic collisions and the necessity of looking for some new
description of elastic hadronic scattering which would not be based on this
theore
Patterns of gene flow and selection across multiple species of Acrocephalus warblers: footprints of parallel selection on the Z chromosome
201
Evolution of structure and local magnetic fields during crystallization of HITPERM glassy alloys studied by in situ diffraction and nuclear forward scattering of synchrotron radiation
Evolution of structure and local magnetic fields in Fe1 xCox 76Mo8Cu1B15 HITPERM metallic glass ribbons with various amounts of Co x 0, 0.25, 0.5 were studied in situ using diffraction and nuclear forward scattering of synchrotron radiation. It was found that crystallization for all three glasses proceeds in two stages. In the first stage, bcc Fe,Co nanocrystals are formed, while in the second stage additional crystalline phases evolve. For all three glasses, the crystallization temperatures at the wheel side were found to be lower than at the air side of the ribbon. The crystallization temperatures were found to decrease with increasing Co content. The lattice parameters of the bcc nanocrystals decrease up to about 550 C and then increase pointing to squeezing Mo atoms out of the nanograins or to interface effects between the nanocrystals and the glassy matrix. Nuclear forward scattering enabled separate evaluation of the contributions that stem from structurally different regions within the investigated samples including the newly formed nanocrystals and the residual amorphous matrix. Even minor Co content x 0.25 has a substantial effect not only upon the magnetic behaviour of the alloy but also upon its structure. Making use of hyperfine magnetic fields, it was possible to unveil structurally diverse positions of Fe atoms that reside in a nanocrystalline lattice with different number of Co nearest neighbour
Forward Physics at the LHC (Elba 2010)
The papers review the main theoretical and experimental aspects of the
Forward Physics at the Large Hadron Collider
Atopic conditions and brain tumor risk in children and adolescents—an international case-control study (CEFALO)
In this study, atopic conditions were not associated with risk of brain tumors in children and adolescents or of glioma in particular. Results are not consistent with findings for adult glioma, possibly explained by a different distribution of histological subtypes. Only a few studies on atopic conditions and pediatric brain tumors are currently available, and the evidence is conflictin
Spectroscopy of -nucleus bound states at GSI and FAIR --- very preliminary results and future prospects ---
The possible existence of \eta'-nucleus bound states has been put forward
through theoretical and experimental studies. It is strongly related to the
\eta' mass at finite density, which is expected to be reduced because of the
interplay between the anomaly and partial restoration of chiral
symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as
an overview of the experimental program at GSI and future plans at FAIR are
discussed.Comment: 7 pages, 3 figures; talk at the International Conference on Exotic
Atoms and Related Topics (EXA2014), Vienna, Austria, 15-19 September 2014. in
Hyperfine Interactions (2015
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