arXiv subjects

Inti Lehmann

Publications and source records attributed to Inti Lehmann.

4 recordsLinked to original sources

arXiv2011

Hadronization in Nuclei - Multidimensional Study

Hadron multiplicities in semi-inclusive deep-inelastic scattering were measured on neon, krypton and xenon targets relative to deuterium at an electron-beam energy of 27.6 GeV at HERMES. These ratios were determined as a function of the virtual-photon energy nu, its virtuality Q2, the fractional hadron energy z and the transverse hadron momentum with respect to the virtual-photon direction p_t . Dependences were analysed separately for positively and negatively charged pions and kaons as well as protons and antiprotons in a two-dimensional representation. These results will help to constrain mechanisms and models of hadronization much more decisively than by the use of integrated results as traditionally done. A few features particular to the two-dimensional representation are highlighted in this contribution.

hep-ex↗

arXiv2009

Physics Programme of PANDA at FAIR

The standard model and Quantum Chromodynamics (QCD) have undergone rigorous tests at distances much shorter than the size of a nucleon. Up to now, the predicted phenomena are reproduced rather well. However, at distances comparable to the size of a nucleon, new experimental results keep appearing which cannot be described consistently by effective theories based on QCD. The physics of strange and charmed quarks holds the potential to connect the two energy domains, interpolating between the limiting scales of QCD. This is the regime which will be explored using the future Antiproton Annihilations at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). In this contribution some of the most relevant physics topics are detailed; and the reason why PANDA is the ideal detector to study them is given. Precision studies of hadron formation in the charmonium region will greatly advance our understanding of hadronic structure. It may reveal particles beyond the two and three-quark configuration, some of which are predicted to have exotic quantum numbers in that mass region. It will deepen the understanding of the charmonium spectrum, where unpredicted states have been found recently by the B-factories. To date the structure of the nucleon, in terms of parton distributions, has been mainly investigated using scattering experiments. Complementary information will be acquired measuring electro-magnetic final states at PANDA.

hep-ex↗

arXiv2007

Exploring the Mysteries of Strong Interactions - The PANDA Experiment

The physics of strong interactions is undoubtedly one of the most challenging areas of modern science. The PANDA experiment will be devoted to charmonium spectroscopy, gluonic excitations (hybrids, glueballs), open and hidden charm in nuclei, gamma-ray spectroscopy of hypernuclei, and selected other topics, which will be studied with unprecedented accuracy. In this overview article we introduce the physics case and the detector array.

physics.ins-det↗

arXiv2007

Vacuum Predictions and Measurements for an Internal Pellet Target

Measurements with low Z targets at internal experiments typically imply a gas load which deteriorates the ring vacuum. Future experiments need reliable estimates for the expected vacuum conditions in order to design 4-pi detectors closely surrounding the interaction area. We present a method for the calculation of the resulting vacuum of such a complex system using a Pellet Target. In order to test the method, a vacuum system with diagnostic tools has been set up and a Pellet Target was operated under realistic conditions. The results for the absolute vacuum agree within factors of two with the expected pressures.

physics.ins-det↗