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We review different aspects of field theory at finite temperature, related to the theory of phase transitions. Finite temperature field theory is discussed in the real and imaginary time formalisms, showing their equivalence in simple examples. Bubble nucleation by thermal tunneling, and the subsequent development of the phase transition is described in some detail. Finally the application to baryogenesis at the electroweak phase transition is done in the Standard Model. We have translated the condition of not washing out any previously generated baryon asymmetry by upper bounds on the Higgs mass.

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After reviewing some basic concepts of the theory of strongly interacting matter above nuclear energy density and reviewing some salient results of the experimental program at the Relativistic Heavy Ion Collider (RHIC), these lectures explain why the quark–gluon plasma observed in the RHIC experiments has been called a “perfect liquid.” They then give an introduction to some recent ideas concerning the possible origin of the nearly inviscid nature of the quark–gluon plasma and discuss the connection between low viscosity and strong parton energy loss of hot QCD matter.

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Jet quenching has become an essential signal for the characterization of the medium formed in experiments of heavy-ion collisions. After a brief introduction to the field, we present the full derivation of the medium-induced gluon radiation spectrum, starting from the diagrammatical origin of the Wilson lines and the medium averages and including all intermediate steps. The application of this spectrum to actual phenomenological calculations is then presented, making comparisons with experimental data and indicating some improvements of the formalism to the future LHC program. The last part of the lectures reviews calculations based on the AdS/CFT correspondence on the medium parameters controlling the jet quenching phenomenon.

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In this lecture I give a short introduction to the high energy limit of hadronic interactions. The elements of the Regge theory, Pomeron in QCD and high energy scattering in AdS/CFT correspondence are presented. I discuss the resummation of the hard Pomeron which in the case of the fixed coupling leads to the value of intercept equal to two in the limit of the strong coupling.

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AdS/CFT correspondence is used to model the dynamics of one-dimen- sional expansion of \(\mathcal {N} = 4\) SYM plasma. Criterium of nonsingularity of the dual geometry is shown to fix both, large proper time dynamics (to be of the perfect fluid type) and subleading corrections to it (viscosity and relaxation time). Time-dependent D7-brane embedding is shown as a first step towards adding a fundamental matter into the expanding plasma.

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We review some aspects of neutrino physics and CP violation both in the quark and lepton sectors.

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We report results of two studies performed by the Belle collaboration in search for a light dark matter candidate. A search for the invisible decay of the \({\mit \Upsilon }(1S)\) via the \({\mit \Upsilon }(3S) \to \pi ^+\pi ^-{\mit \Upsilon }(1S)\) transition yields no signal and an upper limit for the branching fraction at the 90% confidence level is determined to be \({\cal B} ({\mit \Upsilon }(1S) \to {\rm invisible})\ \lt 2.5 \times 10^{-3}\). No significant signal is also observed for the rare decays \(B \to h^{(*)} \nu \overline {\nu }\), where \(h^{(*)}\) stands for a light meson and we set upper limits on the branching fractions at 90% confidence level. The limits on \(B^{\,0} \to K^{\,*0}\nu \overline {\nu }\) and \(B^+ \to K^+\nu \overline {\nu }\) decays are more stringent than the previous constraints, while the first searches for \(B^{\,0} \to K^{\,0} \nu \overline {\nu },\ \pi ^{\,0}\nu \overline {\nu },\ \rho ^{\,0}\nu \overline {\nu }, \ \phi \nu \overline {\nu }\,\) and \(B^+ \to K^{*+}\nu \overline {\nu },\ \rho ^+\nu \overline {\nu }\) are reported.

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We obtain mass distribution for flattened galaxies M94 and M101 whose rotation curves fail sphericity test in thin disk approximation by applying Iterative Spectral Method. The results obtained suggest smaller amount of dark matter (if any) than predicted by classical approach to modelling of rotation curves customarily assuming massive spherical halo.

abstract

Warm dark matter is consistent with the observations of the large-scale structure, and it can also explain the cored density profiles on smaller scales. However, it has been argued that warm dark matter could delay the star formation. This does not happen if warm dark matter is made up of keV sterile neutrinos, which can decay into X-ray photons and active neutrinos. The X-ray photons have a catalytic effect on the formation of molecular hydrogen, the essential cooling ingredient in the primordial gas. In all the cases we have examined, the overall effect of sterile dark matter is to facilitate the cooling of the gas and to reduce the minimal mass of the halo prone to collapse. We find that the X-rays from the decay of keV sterile neutrinos facilitate the collapse of the gas clouds and the subsequent star formation at high redshift.

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The nuclear symmetry energy is directly connected to stability of matter in neutron star interior. At low density symmetry energy determines the crust-core transition. At higher densities, it appears that low values of symmetry energy leads to phase separation. The two phases may coexist and lead to new, unexpected structure of neutron star interior.

abstract

Gravitational waves are propagating fluctuations of gravitational fields, that is, “ripples” in space-time, generated mainly by moving massive bodies. These distortions of space-time travel with the speed of light. Every body in the path of such a wave feels a tidal gravitational force that acts perpendicular to the wave’s direction of propagation; these forces change the distance between points, and the size of the changes is proportional to the distance between these points thus gravitational waves can be detected by devices which measure the induced length changes. The frequencies and the amplitudes of the waves are related to the motion of the masses involved. Thus, the analysis of gravitational waveforms allows us to learn about their source and, if there are more than two detectors involved in observation, to estimate the distance and position of their source on the sky.

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We investigate a Newtonian description of accretion of polytropic perfect fluids onto a luminous compact object possessing a hard surface. The selfgravitation of the fluid and its interaction with luminosity is included in the model. Using appropriate boundary conditions we find stationary, spherically symmetric solutions. For a given luminosity, asymptotic mass of the system and its asymptotic temperature there exist two sub-critical solutions. They differ by the ratio of fluid mass to the total mass.

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We review a steady spherical accretion of perfect fluids and show the effects of selfgravitation of the gas. The mass accretion rate is small either when most of the mass of the system is located in the center and in the contrasting case when the mass of the center is small compared to the mass of the accreting fluid. The maximal value of the accretion rate corresponds to the mass of the central black hole being equal 2/3 of the total mass. The main focus is on the stability of selfgravitating flows. While the stability of the accretion in the test fluid case can be proven analytically, the regime of the massive, selfgravitating fluid requires a numerical analysis. Results obtained in the Newtonian approximation show stability against small and large amplitude perturbations.

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We summarize our results concerning \(p\)-brane propagation through the singularity of the compactified Milne (CM) space. In particular, we present classical and quantum dynamics of a string. We also present our preliminary results on the propagation of a membrane. The CM space seems to be a promising model of the neighborhood of the cosmological singularity deserving further examinations.

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This paper briefly discusses the nature of curvature singularities in asymptotically flat van Stockum spacetimes.

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We discuss certain aspects of Lie-point symmetries in spherically symmetric systems of gravitational physics. Lie symmetries are helpful in solving differential equations. General concepts and a few examples are given: perfect fluid in shearfree motion, the conformal Weyl theory and a higher derivative gravity which is equivalent to General Relativity coupled to certain nonlinear spin-2 field theory.