Science news in the media today is full of stories about Fermilab finding no less than five Higgs particles: God Particles Breeding Like Bosons, The ‘God Particle’ may exist in five forms, Large Hadron Collider’s rival project finds, US experiment hints at ‘multiple God particles’, Fermilab Experiment Hints at Multiple Higgs Particles. The source of these stories can be traced back to this preprint, whose authors then appeared on this radio program, leading to this Symmetry Breaking story.
On May 18 D0 claimed observation of CP violation in processes involving B-mesons of a sort that could not be explained by the SM, at a significance level of around 3 sigma. For an explanation, a good place to look is Resonaances. A violation of the SM is an extraordinary claim, so it requires some extraordinary evidence, and a 3-sigma result is not that extraordinary. The case for such a violation was strengthened by the fact that D0 and CDF had seen a 2-sigma violation of the SM in a similar CP-violating process. The May 23 theory theory preprint tries to explain these SM violations with a model involving two Higgs doublets. Two days later though, on May 25, CDF reported new results: with better data, their 2-sigma SM violation had gone away (now it is 0.8 sigma, completely consistent with the SM). Again, for a good explanation of this, see Resonaances. Somehow, the disappearance of one of the main reasons for taking all this seriously didn’t make it into the Symmetry Breaking story, or any of the flood of ridiculous stories that appeared today.
Thanks for putting this into context… I came across the story in a (usually pretty good) German magazine (or rather, its online edition) and was surprised they’d write about an unpublished paper with unconfirmed results. Now I see where they got the story from…
My old advisor (particle physics) used to make the “Yogi Berra-esque” statement that “3 sigma events happen about half the time.”
Peter have you looked at any of TASI 2010 videos/lectures
which is on string theory?
http://physicslearning2.colorado.edu/tasi/tasi_2010/tasi_2010.htm
There are voices about this new result, to be announced at summer conferences + press release
Thanks Shantanu, hadn’t seen those. Looks like more of the same about the landscape, a lot more about attempts to apply gauge-gravity duality to condensed matter physics.
the broad Higgs,
Now that’s a very interesting rumor…
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The DZero collaboration does not claim that the 3 sigma result proves asymmetry, just that it MAY point to that. The collaboration is happily waiting for CDF or the LHC to cross check its analysis.
The CDF paper released a coupld weeks ago and mention here and in the Resonaances blog does not confirm or disput the DZero result. It is like comparing apples to oranges.
The CDF collaboration did release a sin(2beta_s) result a few weeks ago that looked at CP violation states and found the discrepancy between the amount of particles that decayed to matter versus antimatter in line with the Standard Model, the opposite of what DZero’s study found. The CDF study is an update of a 2007 meson decay analysis that both CDF and DZero conducted where both found discrepancies in the preference for decays to matter and antimatter. The recent CDF update of this analysis, which is being submitted to the scientific journal Physical Review Letters, found a smaller discrepancy than in 2007. DZero has plans to conduct its own update.
However, comparing the updated CDF study and the current DZero asymmetry result is like comparing apples and oranges. True, both studies look at CP violation in meson decays, which can be used to search for “new physics” beyond the Standard Model. However, while the studies look at the same underlying physics, they use vastly different approaches and analysis methods that renders it impossible to draw a conclusion from the CDF study that would deny or confirm the DZero asysmmetry result, according to CDF leaders. Also, the uncertainties of both measurements more than “cover” the disagreement – so neither rules the other one out.
What the CDF study does do is highlight the need for CDF to conduct an apple-to-apple type study of the current DZero result that would have the potential to validate or invalidate it.
While there was some initial discussion, even among CDF collaborators, about whether CDF could perform the same search because the magnet construction in its detector differs from DZero’s, CDF collaborators believe they can reach the same level of sensitivity as DZero to the decays.
CDF conducted a similar apple-to-apple type study several years ago, but with a much smaller dataset, not enough to make a judgment either way, according to collaboration leaders. The DZero result is based on more than 6 inverse femtobarns in total integrated luminosity, corresponding to hundreds of trillions of collisions between protons and antiprotons in the Tevatron collider.
However, the success of CDF’s past study, leads CDF collaborators to believe they can conduct a larger, comparable analysis, although in a slightly different fashion, than the past CDF study and the current DZero study.
The CDF collaboration announced at the Fermilab Users’ Meeting in early
June that it will perform this analysis with its full data set. The duration of the study will depend on the amount of preliminary work conducted, but collaborators estimate a result in time for a presentation at the winter 2011 physics conferences if the CDF search turns out to be as competitive as DZero’s.
You can read an expanded version of this at the updated symmetrybreaking post: http://www.symmetrymagazine.org/breaking/2010/06/04/could-dzero-result-point-to-multiple-higgses/
Tona,
Thanks for clarifying this. However, it should be pointed out that the theory paper about the “five Higgs particles” makes a big deal about the older D0/CDF result indicating non-SM CP violation in a different process, discussing it extensively on the first page of the preprint. The bottom line in this discussion on the first page is that, combining old and new, the new D0 result is 2.5 sigma from the SM. The authors then combine this 2.5 sigma with the old 2.1 sigma deviation to argue that there is a violation at 99.9% confidence level. This argument gets blown away by the new, better CDF measurement, and I assume the authors at some point will revise their preprint to take this into account.
Even with independent 2.5 and 2.1 sigma deviations, it seems to me to be a bad idea to go on the radio trying to sell the highly speculative explanation they have. I don’t know when the radio interview was, but if it was after the release of the CDF result then it was an even worse idea. I listened to the first few minutes of the interview and the extent to which the interviewer had no idea what was going on and the physicists little interest in explaining the highly speculative nature of their work made the whole thing almost comical.
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