EM Algorithm Illustrations

updated: 20-Oct-04

Index

• LM Finding with the ATLAS Algorithm
  • 2,1,1 Style
  • 2,0,1 Style
• EM Isolation with the ATLAS Algorithm
• EM Fraction with the ATLAS Algorithm
• EM Fraction with the Single-TT Algorithm

LM Finding using the ATLAS Algorithm

In the following diagrams the following conventions are used.

1. The data seen by a single Sliding Windows chip is shown on a grid.
2. The main LM is shown in yellow, with its labeling TT marked with an "x".
3. The TTs used in the 2x2 base ROI are marked with an "r".
4. The TTs required to find the LM are marked with an "o" (unless this has been overwritten with an r or x).
5. Some of the nearest possible adjacent LMs are shown in cyan.

2,1,1 Style Algorithm (Vertical LM)

2,1,1 Style Algorithm (Horizontal LM)

2,0,1 Style Algorithm (Vertical LM)

2,0,1 Style Algorithm (Horizontal LM)

EM Isolation with the ATLAS Algorithm

Various possibilities for the definition of the EM Isolation ring are given below. The following conventions are used.

1. The TTs ROI is marked in yellow.
2. The TTs used in the isolation ring are marked in cyan.

4x4 Isolation Ring

3x3 Isolation Ring

3x4 or 4x3 Isolation Ring

EM Fraction with the ATLAS Algorithm

Various possibilities for the definition of the EM Fraction region using the ATLAS algorithm are given below. The following conventions are used.

1. EM TTs used in the ROI are marked with "x" and "o".
2. HAD TTs used in the calculation of the HAD region are marked in red.
3. The actual cut (a) used is:
   • EM(roi) > 2^a * HAD(reg)

4x4 HAD Region

3x3 HAD Region

EM Fraction with the Single-TT Algorithm