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Significant results of scientific activity in year 2012

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A search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented. In the datasets collected at √s = 7 TeV in 2011 and at √s = 8 TeV in 2012 the decay channels H→ZZ(∗)→4ℓ, H→γγ and H→WW(∗)→eνμν have been investigated. Clear evidence for the production of a neutral boson with a measured mass of 126.0 ± 0.4 (stat) ± 0.4 (sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, is compatible with the production and decay of the Standard Model Higgs boson.

The spin Hall effect is a relativistic spin–orbit coupling phenomenon that can be used to electrically generate or detect spin currents in non-magnetic systems. In a Physical Review Letters paper we have introduced an experimental and theoretical work in this field, performed by our international Prague-Nottingham-Cambridge-Texas group. We succeeded in demonstrating electrical spin-injection into a non-magnetic semiconductor combined with electrical detection by the inverse spin Hall effect in an Fe/GaAs microdevice.

An international team of researchers headed by young Oxford physicist Sam Vinko created an unique state of matter by isochorically heating a thin aluminium foil using a tightly focused X-ray beam produced by the LCLS (Linac Coherent Light Source) free-electron laser in California. Solid-density plasmas at a temperature > 106 K were produced under these irradiation conditions. By using the LCLS pulse, the authors have been able to study extremely well-defined hot-dense plasma states for the first time, with unprecedented detail.

According to the theory of superconductivity put forward by Bardeen, Cooper and Schrieffer (BCS), the interaction of valence electrons with vibrations of the ions in the crystal lattice can lead to formation of bound electron pairs. These so-called Cooper pairs then condense into a superconducting state at low temperatures. The BCS theory explains the properties of the so-called conventional superconductors.

The article describes a new measurement of the inelastic proton-air cross-section at a center-of-mass energy 57 TeV per nucleon. The cross-section is one of the basic quantities which characterize the nature of a two-particle collision. Its dependence on energy is connected to collision dynamics and the evolution of this dependence is sensitive to changes in the underlying collision mechanisms.

Conventional ferroelectricity and magnetism are chemically contraindicated in ABO3-type perovskite-structure materials. The presence of unoccupied B d orbitals and the B d – O 2p orbital hybridization are considered as causing the polar ferroelectric distortion (e.g. Ti 3d – O 2p in BaTiO3) in many perovskite ferroelectrics, while the partially filled 3d or 5f orbitals are a prerequisite for magnetism. Moreover, ferromagnetic coupling is favored if the density of states at the Fermi level is high enough.

In order to investigate properties of matter at the smallest distances, we need to initiate, according to Heisenberg principle of uncertainty, processes with the largest possible changes in momentum. Before LHC, the best place to study such processes was collider Tevatron in Fermilab. There, the protons were collided with antiprotons at center of mass energy of √s=1.96 TeV, which was at that time the largest energy available at laboratory.Protons interact with antiprotons mostly through strong interaction.

We have demonstrated a new way to resolve the chemical identity of individual atoms in surface nanostructures. Our method is based on a combination of atomic force microscopy (AFM) measurements with density functional theory (DFT) calculations. This approach significantly enlarges the available means of surface and nanostructure analysis. It allows us to understand semiconductor nanostructures formed on surfaces from many aspects. Namely we can study the process of their formation, their stability, their physical properties as well as chemical composition.

Laser driven ion acceleration is a very promising approach which might drastically reduce the typical size and cost of standard acceleration systems. Nevertheless the laser accelerated beams have to be improved in terms of energy, current, divergence, shot-to-shot stability, etc. In a recent experimental campaign our team has greatly improved both the maximum energy (about 60%) and number (approximately 5 times) of the proton source by using a high intensity laser and advanced nanostructured targets.

Metamaterials are artificial composite structures formed by common materials in a way to exhibit new interesting electromagnetic properties. The geometrical arrangement of the composite on the microscale is of prime importance; as a rule, they rely on regularly arranged resonators with sizes and mutual distances much smaller than the targeted wavelength of the radiation. A proper choice of materials and of their arrangement can induce an unusual electromagnetic behavior. In a given (narrow) spectral range, it is possible to conceive e.g.