### Excuses for why my calculation is wrong

07Sep07

We’ve reached the phase in our project where we perform multiple cross checks on our calculations and code. I spent the better part of today and yesterday checking one particular calculation that had already been confirmed in the analytically, numerically, and in the literature. My task was to check that our code matched the analytical structure that we’d written down. Unfortunately, I’ve been having problems… bits and pieces just don’t seem to fit correctly. Inspired by the big’ ideas in model-building (and one unrelated), I’ve made a list of possible reasons that don’t involve me being a complete idiot, though this is certainly possible. [note: links are to actual literature, some of which I recommend.]

1. Low Energy SUSY. After banging my head on a problem for days, I’m low on energy to keep going. This is experimentally ruled out because my name isn’t Susie. (Ouch! I know, I know… but there are only so many SUSY’ jokes in the universe.)

2. Compositeness (also here and here). The discrepancy isn’t a single error, but has a substructure of many errors. For example, an odd number (greater than one) of sign errors among collaborators.

3. ADD (video review, Bee’s review). These calculations have given me attention deficit disorder.

4. Entropic Principle (video). Given a uniform probability distribution over the space of all possible realities, it’s far more likely that I would find a discrepancy in my calculations rather than an exact match with the correct result. That is to say, I find a value $x = x_\textrm{correct} + \delta$. With no apparent symmetry setting $\delta$ to zero, it’s far more likely to take on some totally, absolutely arbitrary value… perhaps $\delta = \sin^2 \theta_W$.

5. Anthropic Principle. If I weren’t suffering over checking calculations, I wouldn’t be a grad student. But I am a grad student, therefore I must be suffering over checking calculations. In a more general sense: my universe settled into a state that supports intelligent life. If I’m totally incompetent and stupid, then I make everyone else look intelligent.

6. Emergent Phenomena*. The underlying fundamental’ calculation is irrelevant. I’m bound to make errors when I check them in such a way that I’m always wrong. (*- note: the premise of this book is contrary to the entire premise of particle physics.)

7. The Axis of Evil (also cute). Terrorists “hate my freedom” and want to chain me to my calculations.

Anyway, back to checking diagrams. This phase must be a rite of passage among grad students, right? I mean… it can’t just be me; if only because of the Cosmological Principle.

Update (8 Sept 07): I’m only half-inept. The miraculous cancellation’ I was looking for only shows up if I include diagrams that are irrelevant to our project, so my calculations may be correct, but I wasn’t calculating something directly useful.