Add function in RD isolation for vertex isolation online selection of 2-body and 3-body combinations

Add a simple function in rd_isolation to save as extra_outputs two-body and three-body combinations under specific conditions.

• Two-body combinations are persisted if the absolute value of the DELTACHI2 between the combination and the reference particle is smaller than max_two_body_vtx_cut (default: 9);
• Three-body combinations are persisted if the absolute value of the DELTACHI2 between the combination and the reference particle is smaller than make_three_body_combination (default: 15);

Application example in some LFV lines B->K*taul.

Primarily inspired by the work done by @amathad in DaVinci!955

A small modification on the isolation method affects charm implementation (cc: @smaccoli). Trivial modifications are applied.

cc: @mvesteri, @poluekt

added 2024data-selections RD labels

requested review from @rquaglia, @mramospe, @matzeni, and @elsmith

assigned to @tfulghes

added 1 commit

• b7d1c459 - Fixed formatting

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added RTA label

requested review from @alobosal and @htilquin

resolved all threads

added 1 commit

• f467ed02 - Apply @amathad suggestion

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marked this merge request as ready

added isolation label

mentioned in issue #699 (closed)

@matzeni, @mramospe what do you suggest about this MR? Could we proceed with a test to add the possibility of vertex isolation selection for analysts?

Should a BW test be added to MR description to track the change in the lines tested?

mentioned in issue #700 (closed)

/ci-test

added ci-test-triggered label

• [2024-02-08 12:00] Validation started with lhcb-master-mr#10459
• [2024-02-09 10:48] Validation started with lhcb-master-mr#10485

added PR/Moore_hlt2_bandwidth PR/Moore_spruce_bandwidth labels

/ci-test