TsaSeeding

Tsa seeding is a standalone track reconstruction algorithm for the T stations. It is documented in the following LHCb notes:

• Standalone Track Reconstruction in the T-stations
• Updated Performance of the T-Seeding

Here are some older notes that may also be of interest

• The Tsa Reconstruction Framework
• Tsa : Fast and efficient reconstruction for the Inner Tracker
• Track Seeding

The basic idea behind the algorithm is to take three x hits, one from each of the three T stations, and make a parabola out of them. Then one collects all x hits in a window around that parabola. If enough x hits are found, and some quality cuts are passed, one has a track candidate in xz projection. For each such candidate, the algorithm proceeds to find two compatible stereo hits, draws a straight line through these two points, and collects all stereo hits in a window around it. If the track passes some quality cuts, it is accepted for a final competition phase designed to kill ghosts and clones. There is also special some treatment for IT tracks that go through dead regions or are otherwise more difficult to find which is based on a stub building approach, see the notes for details.

Special Tunings:

• running without magnetic field
• running only on hits in a region of interest (e.g. for L0 confirmation in the HLT)

Note:

• When run in the standard reconstruction setup, TsaSeeding is configured to put its tracks into the default location Rec/Track/Seed. If you configure it yourself, you have to run a seed track conversion algorithm, TsaSeedTrackCnv, which will output to Rec/Track/Tsa by default.

-- ManuelSchiller - 13 Aug 2008