Search results

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.

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.

Self-organizing neural networks are briefly reviewed and compared with supervised learning algorithms like back-propagation. The power of self-organization networks is in their capability of displaying typical features in a transparent manner. This is successfully demonstrated with two applications from hadronic jet physics; hadronization model discrimination and separation of b, c and light quark

We construct a QCD-based model where soft gluon rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. The model successfully describes the precise HERA data on the diffractive deep inelastic structure function in the whole available kinematical range.

We construct a QCD-based model where soft gluon rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. The model successfully describes the precise HERA data on the diffractive deep inelastic structure function in the whole available kinematical range.

GHRS observations of chemically peculiar stars have initiated a new project for calculating atomic properties of heavy elements (Z approximate to 80). The method used is based on large-scale, fully relativistic MCDF, and the data involve accurate gf-values, hyperfine structure parameters, and relative isotope shifts.

We give a short overview of the theory of the muon anomalous magnetic moment with emphasis on the hadronic light-by-light and the pion loop contribution. We explain the difference between the hidden local symmetry and full VMD pion loop and discuss leading logarithms in the anomalous sector of 2-flavour chiral perturbation theory.

A linear system – one that extracts materials and then puts them in landfills and incinerates them, thus creating a demand for even more materials – is fundamentally unsustainable. Swedish waste management is thought by many to be progressive and at the forefront, when looking at the waste hierarchy. While there is a ban on landfilling non-hazardous and organic waste in Sweden, around 50% is incin

Following the recent discovery of the first radial velocity planet in a star still possessing a protoplanetary disc (CI Tau), we examine the origin of the planet's eccentricity (e ~0.3). We show through long time-scale (10^5 orbits) simulations that the planetary eccentricity can be pumped by the disc, even when its local surface density is well below the threshold previously derived from short ti

We report on the observation of the bright, long gamma-ray burst, GRB 090926A, by the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn

The conceptual design of the Large Earth-based Solar Telescope (LEST)has evolved through the years. In 1995-97 it was discussed whether atechnology demonstration telescope could be built at a lower cost thanthe LEST originally proposed. In 1997, a de-scoped LEST design, theso-called "Mini-LEST", was conceived and proposed to the LEST community.The telescope has an innovative design with a small fi

Främlingsfientligheten är ett växande problem i Sverige. Främlingsfientliga organisationer demonstrerar, håller offentliga möten, ställer upp i riksdagsval och antal anmälningar om hatbrott ökar. Efter andra världskriget och förintelsen som satte starka spår i mänsklighetens historia agerade världssamfunden på olika sätt för att aldrig mer behöva uppleva de förföljelser och folkmord som skedde. EtXenophobia is a growing problem in Sweden. Xenophobic organizations are demonstrating, holding public meetings, set up in the general election and the number of complaints of hate crimes is increasing After World War II and the Holocaust that put strong traces in the history of mankind the global communities acted in different ways to never have to experience the persecution and genocide that took

We discuss the point spread function for the Spectro instrument based on realistic effects of the time delayed integration, transverse image motion and pixelization, but assuming rather small wave front errors. Stars brighter than 10 mag, which will saturate the CCD, may be observed photometrically using the image wings, but the central wavelengths will be slightly shifted towards the red.

beans is a tool for distributed data analysis. It provides web and command line interface for data analysis and plotting for huge datasets. beans is written in a general form and can be used in any field of research to analyze the data. The main purpose of beans is to provide to the community a versatile tool to store, analyze and then visualize any amount of scientific data (e.g. numerical simula