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In high energy collisions saturation and multiple collisions are most easily accounted for in transverse coordinate space, while analyses in momentum space have been more suitable for calculating properties of exclusive final states. In this paper I describe an extension of Mueller's dipole cascade model, which attempts to combine the good features of both these descriptions. Besides saturation it
We report on experimental absolute oscillator strengths for 18 UV lines of Ru II, obtained by combining laser-induced fluorescence measurements of radiative lifetimes and branching fractions from line intensities in a calibrated Fourier-transform spectrum. HST/GHRS observations of the spectrum of the sharp-lined B star chi Lupi contain six of these lines, for which ''astrophysical'' relative f-val
The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray observatory currently under construction. It will improve over the current generation of imaging atmospheric Cherenkov telescopes (IACTs) by a factor of five to ten in sensitivity and it will be able to observe the whole sky from a combination of two sites: a northern site in La Palma, Spain, and a southern one in Paranal, Chile.
Heta Jupitrar är gasjättar som Jupiter vars omloppsbana för dem närmre sin värdstjärna än Merkurius bana kring Solen. Sen deras upptäckt har de visat sig vara väldigt viktiga i vår förståelse för exoplanet-atmosfärer. På Jorden minskar temperaturen av atmosfären med höjd över marken, förutom i ett område där temperaturen plötsligt går upp igen då ozonet som fångar UV-ljuset befinner sig på den höjContext. The discovery of hot Jupiters, giant gas exoplanets on tight orbits close to their host star, has proven instrumental in the study of exoplanet atmospheres through transit spectroscopy. Just as a temperature increase with height manifests in Earth’s atmosphere due to ozone absorbing ultraviolet radiation, transit spectra of some hot Jupiters has yielded evidence that suggests the presence
In the spectral region 2400-3160A of Eta Carinae, we have identifiedapproximately 500 absorption lines each with up to twenty velocitycomponents.The -512 km/s component is truely unique as 1) the typicalline width is <3 km/s, 2) the identified lines are in Fe I, Fe II, VII and Ti II, and 3) the lines originate from lower levels up to 2000cm-1 above the ground level. We have measured the velocity c
The purpose of this essay was to find out why people who had used alcohol and narcotics for a long time, stoped using drugs. If there were any special occurrences, personal skills or surroundings that influenced sobernes. The main questions were: · Why stop using drugs? · How has the way to a drug free life turned out? · Were there any special occurrances or factors that started the drug free life
This thesis gives a thorough description of the icing mechanisms in gas turbines, the underlying physics of ice and ice types that can form in gas turbines. The primary intention of this thesis is to investigate the icing condition regions leading to ice formation in gas turbines. The icing problem in gas turbines is explained in detail in this thesis. The different ice types, icing mechanism
We present a novel event-generation framework for the efficient simulation of vector boson plus multijet backgrounds at the high-luminosity LHC and at possible future hadron colliders. Message passing interface parallelization of parton-level and particle-level event generation and storage of parton-level event information using the HDF5 data format allow us to obtain leading-order merged Monte Ca
I solsystemet kan vi se åtta planeter, flera dvärgplaneter och mängder av asteroider och kometer kretsande runt Solen. I planetariet kan vi lära oss om Jorden och månen, säsonger och stjärnorna. Vi utforskar solsystemets åtta planeter, lär oss om stjärnbilderna och att bara för att det kallas för "stjärnfall" betyder det inte att stjärnor kan falla från himlavalvet.We have eight planets, quite a few dwarf planets and a lot of asteroids and comets orbiting the Sun. In the planetarium we can learn about the Earth and the Moon, the seasons and the stars. We explore the planets of the solar system, learn about the constellations and discover that just because it is called "a shooting star" does not mean that stars can fall from the skies.
In a previous report we used the Linked Dipole Chain model unintegrated gluon densities to investigate the uncertainties in the predictions for central exclusive production of scalars at hadron colliders. Here we expand this investigation by also looking at other parameterizations of the unintegrated gluon density, and look in more detail on the behavior of these at small k(<^>). We confirm our co
We study the decays $K\to\pi\pi$ in one-loop two-flavour Chiral Perturbation Theory. We provide arguments why the calculation of the coefficient of the pionic chiral logarithm $\logm = M^2\log M^2$ is unique and then perform the calculation. As a check we perform the reduction of the known three-flavour result. Our result can be used to perform the extrapolation to the physical pion mass of direc
We study the deeply virtual Compton scattering off a spin-one particle, as the case for the coherent scattering off a deuteron target. We extend our approach, formulated initially for a spinless case, and discuss the role of twist three contributions for restoring the gauge invariance of the amplitude. Using twist three contributions and relations, which emanate from the QCD equations of motion, w
We review transverse momentum dependent (TMD) parton distribution functions, their application to topical issues in high-energy physics phenomenology, and their theoretical connections with QCD resummation, evolution and factorization theorems. We illustrate the use of TMDs via examples of multi-scale problems in hadronic collisions. These include transverse momentum q(T) spectra of Higgs and vect
We use one-loop Heavy Meson Chiral Perturbation Theory (HMChPT) as well as a relativistic formulation to calculate the chiral logarithms m(pi)(2) log (m(pi)(2)/mu(2)) contributing to the formfactors of the semileptonic B -> pi decays at momentum transfer q(2) away from q(max)(2) = (m(B) - m(pi))(2). We give arguments why this chiral behaviour is reliable even in the energy regime with hard or fast
Context. Elements heavier than Li are produced in the interiors of stars. However, for many elements the exact production sites and the timescales on which they are dispersed into the interstellar medium are unknown. Having a clear picture on the origins of the elements is important for our ability to trace and understand the formation and chemical evolution of the Milky Way and its stellar popula
We add the Wess-Zumino-Witten term to the N = 3 massive nonlinear sigma model and study the leading logarithms in the anomalous sector. We obtain the leading logarithms to six loops for pi(0) -> gamma*gamma* and to five loops for y*pi pi pi. In addition we extend the earlier work on the mass and decay constant to six loops and the vector form factor to five loops. We present numerical results for
We investigate the ground-state energy of the pi(-)p atom (pionic hydrogen) in the framework of QCD + QED. In particular, we evaluate the strong energy-level shift. We perform the calculation at next-to-leading order in the low-energy expansion in the framework of the relevant effective field theory. The result provides a relation between the strong energy shift and the pion-nucleon S-wave scatter
It is argued that the assumption that the standard model particles live on a finite brane in the ADD model does in itself imply a finite propagator for virtual Kaluza-Klein mode exchange. The part of the propagator relevant for large distance scattering is cut-off-independent for scattering at distances large compared to the brane width. The matrix element corresponding to this part can also, at l
