- The big news of the past couple days has been the release of more data by CDF which continues to show a bump in the invariant mass of two jets produced with a W. Resonaances gives an excellent description of this and its possible significance. Tommaso Dorigo remains a skeptic.
I can’t do better than the two of them on this story, but here’s my summary take on the situation:
With the new data, this can no longer be written off as a statistical fluke. 3 sigma you can argue away as such a fluke, but not 5 sigma.
The main reason to be skeptical though hasn’t been the statistical significance, but the possibility that this is due to bad modeling of the background. The signal is being extracted from a huge background, so a small misunderstanding of the background could be its cause. If this is the case, the new data changes nothing, you expect to continue to see the effect as more data is analyzed.
The fact that Tommaso is a skeptic carries a lot of weight, since he works on the CDF experiment and understands the problems well. In general, experimentalists want the experiments they work on to make great discoveries, so tend to be optimists about their own results. When someone is skeptical about a result of their own experiment, that should give one pause.
What would really make the case for new physics here more compelling would be if the result is confirmed by one of the other experiments (DO at Fermilab, CMS or ATLAS at the LHC) that should be able to see the same effect if it is there. These groups have a certain motivation to not just confirm their competition’s discovery (raising the question of why they didn’t find this first), but to convincingly shoot it down. This posting by Pauline Gagnon of ATLAS says that they see nothing in their 2010 data. One expects that D0 is hard at work and should soon release whatever they have found. ATLAS and CMS should also be hard at work looking at the much larger 2011 data samples. We’ll know soon the results, but the public comments of Dorigo and Gagnon don’t sound to me like those they would be making if they knew their experiments had preliminary confidential results confirming the CDF anomaly.
Finally, while there are lots of theory papers out already with supposed models explaining this, none are really compelling. This is not an experimental result with an obviously attractive theoretical explanation.
- Abstruse Goose has commentary on SUSY here.
- In gossip of the mathematics world, it looks like Princeton (the IAS) has stolen away number theorist Richard Taylor from Harvard.
- Video of Graeme Segal’s Felix Klein lectures this spring at Bonn on quantum field theory are now available, and well worth watching.
- Other interesting video available is Greg Moore’s lectures on geometry, topology and QFT at Rutgers last fall.
- For pictures from this years Physics of the Universe Summit, see here. Any info beyond the transparencies caught in the pictures seems to be private.
- The journal Foundations of Physics will be putting out an issue on “Forty Years of String Theory”. So far articles intended for this have appeared on the arXiv from Dean Rickles, Steven Gubser, and, last night, Steven Giddings. The Giddings contribution is entitled Is string theory a theory of quantum gravity?, and provides an unusually hype-free discussion of the relevance of gauge/gravity duality to hopes to use string theory to understand quantum gravity, writing:
While string theory addresses some problems of quantum gravity, its ability to resolve these remains unclear. Answers may require new mechanisms and constructs, whether within string theory, or in another framework.
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