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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Monte Carlo simulations of D-mesons with extended targets in the PANDA detector

Gustafsson, Mattias January 2016 (has links)
Within the PANDA experiment, proton anti-proton collisions will be studied in order to gain knowledge about the strong interaction. One interesting aspect is the production and decay of charmed hadrons. The charm quark is three orders of magnitude heavier than the light up- and down-quarks which constitue the matter we consist of. The detection of charmed particles is a challenge since they are rare and often hidden in a large background. There will be three different targets used at the experiment; the cluster-jet, the untracked pellet and the tracked pellet. All three targets meet the experimental requirements of high luminosity. However they have different properties, concerning the effect on beam quality and the determination of the interaction point. In this thesis, simulations and reconstruction of the charmed D-mesons using the three different targets have been made. The data quality, such as momentum resolution and vertex resolution has been studied, as well as how the different targets effect the reconstruction efficiency of D-meson have been analysed. The results are consistent with the results from a similar study in 2006, but provide additional information since it takes the detector response into account. Furthermore, a new target distribution have been implemented in the software package. This is the first results obtained from a cylindrical target distribution. The results are very important for PANDA since they show the limitations of different target types regarding the possibilities to reduce background. Simulations with the new target distribution have been made for all three targets and the results are presented.
2

Experimental Studies of Neutron Emission Induced by Heavy-Ion Scattering

Nadel-Turonski, Pawel January 2003 (has links)
<p>A beam of 250A MeV <sup>17</sup>O ions was scattered from argon and xenon targets. The large excess of fast neutrons compared with statistical model calculations that was observed earlier for xenon, was confirmed and found for argon as well. Analysis and calculations show that a considerable fraction of these neutrons can be interpreted as coming from direct knock-out reactions.</p><p>The angular distributions do not support the suggestion of using fast heavy ion scattering as a probe for the study of the neutron skin in nuclei. While the basic idea that a heavy projectile tends to sample the neutron wave function near the surface of the nucleus is sound, the measured neutron distribution is not as distinct as suggested by the previous experiment. This makes it difficult to distinguish direct reactions from other channels, such as semi-direct decay of giant resonances.</p><p>The improvements in the experimental methods have made the concept of using the CELSIUS storage and cooler ring as an internal magnetic spectrometer attractive for other of experiments presently being prepared.</p>
3

Experimental Studies of Neutron Emission Induced by Heavy-Ion Scattering

Nadel-Turonski, Pawel January 2003 (has links)
A beam of 250A MeV 17O ions was scattered from argon and xenon targets. The large excess of fast neutrons compared with statistical model calculations that was observed earlier for xenon, was confirmed and found for argon as well. Analysis and calculations show that a considerable fraction of these neutrons can be interpreted as coming from direct knock-out reactions. The angular distributions do not support the suggestion of using fast heavy ion scattering as a probe for the study of the neutron skin in nuclei. While the basic idea that a heavy projectile tends to sample the neutron wave function near the surface of the nucleus is sound, the measured neutron distribution is not as distinct as suggested by the previous experiment. This makes it difficult to distinguish direct reactions from other channels, such as semi-direct decay of giant resonances. The improvements in the experimental methods have made the concept of using the CELSIUS storage and cooler ring as an internal magnetic spectrometer attractive for other of experiments presently being prepared.

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