List of Figures

1. CKM unitarity triangle.
2. The space-time evolution of a heavy-ion collision, which undergoes a phase transition to a QGP [#!lamot!#].
3. The layout of the accelerators and experiments situated at DESY in Hamburg. Left: Overview over the complete facility. Right:The pre-accelerators DESY-II and PETRA and the Hall West where the HERA-B is placed.
4. Left: Schematic view of vertex detector vessel. The target mechanics are seen. Right: Positions of reconstructed primary vertices during a multi-wire run.
5. Three-dimensional view of the HERA-$B$ detector.
6. Schematic illustration of the first level trigger track tracing algorithm.
7. Schematic top and side view of the HERA-B experiment. From right to left can be seen vertex vessel with target wires, magnet, tracking stations, RICH vessel, electromagnetic calorimiter and muon system (2002-2003 setup).
8. Simulated electrical field of the MSGC is shown. Gas amplification possible near the anodes which are located in the region with a maximum field strength. The typical sizes are indicated.
9. Left: a GEM foil used for the ITR system is shown. Right: The simulated electrical field inside the GEM hole is shown.
10. Sketch of the GEM-MSGC chamber used in the Inner Tracker system. The typical dimensions are indicated.
11. Location of the Inner Tracker superlayers along the beam axis (configuration of 2002). The $z$ positions are indicated.
12. Mounting of the two half stations on the frame of the Outer Tracker station. The dimensions given for the chambers situated in the PC area.
13. The drawing shows the construction of the support plates with mounted GEM-MSGC chambers. In order to cover all four quadrants, two layers of the supports are needed.
14. A typical simulated event: $J/\psi \rightarrow \mu ^+\mu ^-$ decay superimposed with two inelastic interactions. For details see text.
15. Flow chart of the track recognition process implemented in CATS.
16. The method for hit clusterization in the OTR.
17. Reconstruction of space-points -- short 3D track segments inside superlayers.
18. Track candidates reconstructed by the cellular automaton after the track following procedure.
19. The final event reconstruction.
20. Left: segment track model in a two-arm elastic neural net, right: ENN node dynamics -- for details see text.
21. Reconstruction efficiency for reference tracks and ghost level versus the number of superimposed (exactly mixed) inelastic interactions
22. Mean computing time per event versus the number of superimposed (exactly mixed) inelastic interactions.
23. On the left, occupancy for chamber MS01++4. On the right, wiremap for chamber MS01++4.
24. On the left, wiremap for chamber MS01++4. On the right, wiremap with dark color masked strips are shown for chamber MS01++4.
25. Sketch of an ITR chamber indicating the distribution of PCBs over the chamber.
26. On the left, a wiremap for chamber MS10++4. On the right, a wiremap with masked strips shown in dark color for chamber MS10++4.
27. On the left, efficiency vs run for the chamber MS01 ++ 1. In the middle, signal over noise vs run for chamber MS01 ++ 1. On the right, fraction of masked channels vs run for chamber MS01 ++ 1.
28. Correlation of measured efficiency versus signal over noise for the run 21056 for chambers of the PC region. Statistical errors are shown as error bars.
29. Efficiencies for all chambers of the superlayer MS01 for the run 20794. Efficiencies measured with help of mask are shown with filled triangles and with transparent triangles efficiencies measured without applying any masks. Statistical errors are shown as error bars.
30. Mean efficiency distribution for the MS01 superlayer. Standard deviations are shown as error bars.
31. From left to right for the chamber MS10-+2: efficiency vs run number, signal over noise vs run number, fraction of masked channels vs run number. For the efficiency plot statistical errors are shown.
32. Mean efficiency distribution for the PC superlayers. Standard deviations are shown as error bars.
33. From the left to the right for the chamber MS10 ++ 4: efficiency vs run, signal over noise vs run, average GEM voltage vs run.
34. From the left to the right for the chamber MS12 - 1: efficiency vs run, signal over noise vs run, average GEM voltage vs run.
35. Mean efficiency distribution for the TC superlayers. Standard deviations are shown as error bars.
36. Hit efficiencies distribution obtained with Monte Carlo data for chambers of the Inner Tracker in the MS01 station, PC and TC area. Statistical errors are shown as error bars.
37. Schematic overview over data taking and simulation chains. The picture is based on [#!AGA!#]
38. On the left, number of hits used in the Silicon detector for the track segment reconstruction. On the right, number of hits used in the Main tracker (ITR+OTR) for the track segment reconstruction. The chosen cut values are indicated by the vertical arrows.
39. On the left, the dependence of signal and background on the cut on the applied distance between two tracks is shown. In the middle plot, the dependence of signal and background on the applied impact parameter cut. On the right, the dependence of signal and background on the applied flight path cut. The chosen cut values are indicated by the vertical arrows.
40. On the left, the Armenteros-Podolanski plot for $K^0_S ,\, \Lambda ,\, \bar \Lambda$ candidates reconstructed in run 20677. Right, the Armenteros-Podolanski plot after removal of overlap in the masses.
41. Top: Resulting residual distributions $X_{gen}$- $X_{rec}$ for the $x_F$ variable of $K^0_S ,\, \Lambda ,\, \bar \Lambda$. Bottom: Resulting residual distributions $X_{gen}$-$X_{rec}$ for the $p_t^2$ variable of $K^0_S ,\, \Lambda ,\, \bar \Lambda$. Only $V_0$ candidates which were selected by the same analysis algorithm are used for these plots.
42. Reconstructed secondary vertex $Z$ coordinate distribution for run 20678 taken with Below I wire (Carbon). The cut applied in the analyzed events is indicated.
43. Geometrical acceptances for $V_0$s.
44. Acceptances for $V_0$s, including geometrical acceptances and reconstruction efficiencies. For the acceptance determination the standard MC sample for Below I wire (Carbon) was used.
45. Dependence of energy deposited in the ECAL as a function of the interaction rate for carbon and titanium wire obtained with the help of rate scans.
46. Distribution of the average number of interactions measured with VDS and ECAL methods relative to the measurements obtained with Hodoscopes for the Tungsten wire [#!Asompriv!#].
47. Comparison of $K^0_S$ properties in MC and data. (filled triangles: MC, empty triangles: data.)
48. Comparison of $\Lambda$ properties in MC and data. (filled triangles: MC, empty triangles: data.)
49. Comparison of $\bar \Lambda$ properties in MC and data. (filled triangles: MC, empty triangles: data.)
50. Left: distribution of the number of hits used in the Inner Tracker detector for reconstruction of track segments (run 20768). The applied cut is indicated by the arrow. On the right, the $x_F$ distribution for $K^0_S$ obtained with tracks with a large fraction of ITR hits (dashed), overlapped with $x_F$ distribution obtained with all tracks.
51. Number of $K^0_S$ reconstructed with all tracks (OTR+ITR) and number of $K^0_S$ reconstructed with tracks with a large fraction of ITR hits in the run 20695. Each bin contains approximately 50,000 consecutive events.
52. $V_0$ signals found in the 2002/2003 minimum bias data set. From the top to the bottom: invariant mass distributions for $K^0_S$, $\Lambda$ and $\bar \Lambda$ candidates for runs taken Inner I and Inner II wires.
53. $V_0$ signals found in the 2002/2003 minimum bias data set. From the top to the bottom: invariant mass distributions for $K^0_S$, $\Lambda$ and $\bar \Lambda$ candidates for runs taken Below I and Below II wires.
54. The differential production cross sections $\mathrm {d} \sigma _{pA} / \mathrm {d}p_t^2$ for $V_0$ for three target materials (Carbon, Titanium and Tungsten).
55. The ratio of $\sigma (\bar \Lambda) / \sigma (\Lambda)$ determined at mid-rapidity for the used targets.
56. The $V_0$ total production cross section as a function of atomic mass A of the target material. The solid lines show fits by the $\sigma _{pA} \varpropto A_{\alpha }$ function.
57. The $V_0$ total production cross section per nucleon as a function of atomic mass A of the target material.
58. Production cross section of $V_0$ as a function of $s$ (the square of center of mass energy). Measurements obtained with the 2000 and 2002 Minimum bias data are shown with black symbols, open symbols represent measurements done by another experiments.
59. Ratio of production cross sections $\sigma (\bar \Lambda) / \sigma (\Lambda)$ determined at mid-rapidity as a function of $\sqrt {s}$. Measurements obtained with the 2002 Minimum bias data are shown with black symbol, open symbols represent measurements done by another experiments.