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Solen är inte den enda stjärnan med planeter i universum. Sedan 1995, då den första extra-solära planeten upptäcktes, har 770 exoplaneter observerats och fler upptäcks hela tiden. Enligt teorier om hur planeter formas föds gasjättar med cirkulära, vida banor långt från sin stjärna precis som planeterna i solsystemet. Trots detta har många av de observerade exoplaneterna väldigt elliptiska (excentrAccording to theories of planet formation, jovian planets are formed on relatively circular, non-inclined, wide orbits. Despite this, many observed jovian planets are found on tight eccentric orbits. This problem could possibly be solved with multiple-planet systems. A planet in a multiple-planet system is not only affected by the host star but also by the other planets. The interactions express t

A recent theoretical model by Andersson et al. proposes that soft gluons order themselves in the form of a helix at the end of the QCD cascades. The Authors of the model present a measure of the rapidity-azimuthal angle correlation, which they call screwiness. We searched for such a signal in DELPHI data, and found no evidence for screwiness.

From novel findings to groundbreaking products: Edouard Berrocal, a senior lecturer at the Physics Department developed a new method for testing cloudy liquids using scattered light. Learn about how he is combining his academic career with his role as the founder of Spec-Imaging AB. Tell us about Spec-Imaging – the company based on your research. What problem are you solving?“Previously, doing acc

https://www.innovation.lu.se/en/i-find-solutions-problems-have-never-been-solved - 2026-05-19

The CP conserving amplitudes for the decays K --> 3pi are calculated in Chiral Perturbation Theory. The calculation is made at the next-to-leading order including strong and local electromagnetic isospin breaking. A comparison is made between the squared amplitudes with and without isospin violation to estimate the size of the effect. We find corrections of order five percent in the amplitudes.

The production of jets is studied in collisions of virtual photons, specifically for applications at HERA. Photon flux factors are convoluted with matrix elements involving either direct or resolved photons and, for the latter, with parton distributions of the photon. Special emphasis is put on the range of uncertainty in the modeling of the resolved component. The resulting model is compared with

Oscillator strengths for 57 U II lines in the region 3500-6700 Åhave been derived by combining new branching fraction measurements withrecently measured lifetimes. The lines combine six upper levels withnumerous low levels having excitation energies of 0-1.5 eV. The datainclude the U II line at 3859 Å, which is used forcosmochronology.

We have computed the quark anti-quark expectation value in finite volume at two loop in chiral perturbation theory and compare it with a formula obtained in analogy to the Luscher formula for pion mass in finite volume. We observe that due to the small finite size correction at two loop it is not possible to obtain conclusions on the accuracy of the extended Luscher formula

We describe an algorithm for improving subsequent parton shower emissions by full SU(3) color correlations in the framework of a dipole-type shower. As a proof of concept, we present results from the first implementation of such an algorithm for a final state shower. The corrections are found to be small for event shapes and jet rates but can be more significant for tailored observables.

A short overview of eta and eta' decays is given with an emphasis on what can be learned for the strong interaction from them. The talk consists of a short introduction to Chiral Perturbation Theory, a discussion of eta -> 3 pi beyond p(4) and some of the physics involved in eta' -> eta pi pi, 3 pi as well as an overview of anomalous processes.

__________________________________________________________________]Thesis title] ________________________________________________________________[your name/s] Interview Consent Form. I have been given information about ________________________________________________ [thesis title] and discussed the research project with _____________________________________________[your name/s] who is/are conduct

https://www.ehl.lu.se/sites/ehl.lu.se/files/2024-02/lusem-bachelor-master-thesis-consent-1.docx - 2026-05-20

We summarize the activities of Working Group 2 of the HERA/LHC Workshop dealing with multi-jet final states and energy flows. Among the more specific topics considered were underlying event and minimum bias, rapidity gaps and survival probabilities, multi-jet topologies and multi-scale QCD, and parton shower–matrix element matching.

By providing the Lund Model fragmentation process with a quantum-mechanical framework we extend the results of previous work to situations where there are very many identical bosons. We investigate the features of the weight distributions in some detail and in particular exhibit three-particle BE-correlations, the influence on the rho-spectrum and the difference between charged and neutral pion co

In this paper I discuss the dynamics of particle production in high energy reactions. It includes parton cascades and hadronization in e(+)e(-)-annihilation, small x evolution including the Double Leading Log approximation and the BFKL equation, saturation at high densities and the BK equation, and finally the Lund Dipole Cascade model for high energy collisions, which is implemented in the DIPSY

A Mathematica package for color summed calculations in QCD (SU(N-c)) is presented. Color contractions of any color amplitude appearing in QCD may be performed, and the package uses a syntax which is very similar to how color structure is written on paper. It also supports the definition of color vectors and bases, and special functions such as scalar products are defined for such color tensors.

We present a formalism which modifies the Mueller Dipole Model such that it incorporates energy-momentum conservation and also important colour suppressed effects. We implement our formalism in a Monte Carlo simulation and compare the results to inclusive data from HERA and the Tevatron, where we see that there is a good agreement between the data and our model.

We have extended the laser probing technique at the CRYRING storage ring to measurement of the extremely long lifetime (28 s) of the metastable 3d2(3P)4s b 4P5/2 level in Ti II. The result obtained demonstrates the power of this method for investigation of such long-lived levels. This is the first experimental lifetime investigation of metastable states in Ti II.

Current optical space telescopes rely upon silicon charge-coupled devices (CCDs) to detect and image the incoming photons. The performance of a CCD detector depends on its ability to transfer electrons through the silicon efficiently, so that the signal from every pixel may be read out through a single amplifier. This process of electron transfer is highly susceptible to the effects of solar proto

Numerical evidence for a nonvanishing 0++ glueball mass in three-dimensional SU(2) is presented. By using a long-distance correlation Monte Carlo method we obtain m0++ = (4.7±1.2)√σ in the β-range 4.0-6.5. The measurements are consistent with 1/β-scaling. The relevance of this result for SU(2) in four dimensions at finite temperature is briefly discussed.