Discussion Overview
The discussion revolves around the calculation of the missing transverse momentum azimuthal angle (φ) in particle physics, specifically addressing the formula used and its implications for the range of φ. Participants explore the nuances of using arctan versus atan2 and the conventions in scientific literature.
Discussion Character
- Technical explanation
- Debate/contested
Main Points Raised
- One participant questions how the formula φ^{miss} = arctan(E_y/E_x) can cover the full range of φ ∈ [-π, π] without considering cases where E_x < 0.
- Another participant suggests that using ATan2(x,y) accounts for the signs of the components, which resolves the issue raised.
- Concerns are raised about the lack of mention of atan2 in a specific paper, with some participants suggesting that such omissions may stem from common conventions in the field.
- It is noted that many particle physicists are familiar with these conventions, and repetitive explanations may be seen as unnecessary in technical notes.
- One participant expresses frustration over the potential confusion caused by the use of arctan instead of atan2, suggesting that the latter is clearer.
- Another participant argues that atan2 is not a standard mathematical function, and its use may not be optimal in presentation.
- A participant recalls a previous paper that used arctan(Ey,Ex), which they found clearer, and mentions the convenience of retrieving φ directly from their truth derivation.
- Discussion includes a humorous exchange about seasonal stress affecting cognitive function.
- A participant shares a personal anecdote about confusion stemming from differing definitions of atan2 in programming languages, illustrating the complexity of the topic.
- One participant proposes an alternative definition for φ that incorporates the sign of E_y and uses arccos, suggesting it could be a clearer representation.
Areas of Agreement / Disagreement
Participants express differing views on the clarity and appropriateness of using arctan versus atan2, with no consensus reached on the best approach. The discussion reflects a mix of agreement on the familiarity of the conventions and disagreement on the presentation of the formulas.
Contextual Notes
Participants highlight the potential for confusion due to varying definitions of mathematical functions in different programming languages, as well as the assumptions made in scientific literature regarding the audience's familiarity with certain conventions.
