HLT2 line naming convention
For the sake of giving line authors as little to think about as possible, it'd be useful to have some conventions for naming HLT2 lines. These should be given in the CONTRIBUTING file, along with the outcomes of #54 (closed) and #58.
The general purpose of a line name is to describe what physics the selection intends to capture, which for most lines is some exclusive decay of a specific particle. Charge conjugation is almost always implied.
The exact conventions are not particularly important so we shouldn't spend much time discussing them.1 Here's a list that roughly follows what I've seen the most in Run 2; we should expand this list if it leaves ambiguities, and change items if they are ambiguous or are otherwise unhelpful.
- Start with
Hlt{module}
, end withLine
, and contain only alphanumeric characters and underscores (already enforced).- We currently do not have module structure, e.g.
CharmHad
, but will likely introduce one soon.
- We currently do not have module structure, e.g.
- The first letter of a particle name is always capitalised, the remaining are lowercase
-
Jpsi
notJPsi
-
Pi
notpi
-
- Separate parent and children in a decay with
To
(not2
)D0ToKK
- Particle charges can be specified for clarity
-
D0ToKmPip
andD0ToKpPim
DpToKmPiPip
-
BuToJpsiKp
orBuToJpsiK
-
- Cascade decays can be separated with underscores
XiccppToLcpPip_LcpToppKmPip
- 'Standard' decay modes can be left unspecified
-
BsToJpsiPhi
, whereJpsiToMuMu
andPhiToKK
are implied -
D0ToKS0PipPim
, whereKS0ToPipPim
is implied
-
- Qualifiers can be prepended to
Line
-
Detached
,Incl
,LL
-
We can consider enumerating:
- Labels for particles (e.g. to avoid "
Dstar
orDst
?") - Standard decays
-
I don't think we should try to define a completely internally consistent grammar or anything similarly heavy; we don't parse line names. At the end of the day they're just labels.
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