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ICHEP-2010 vs hints of New Physics July 21, 2010

Posted by apetrov in Particle Physics, Physics, Science.
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Once of the major meetings in particle physics, the International Conference on High Energy Physics (ICHEP 2010) gets underway today in Paris. This is a conference that happens every two years and usually brings together hundreds of physicists from all over the world. Usually this is the place where large and small collaborations present their recent findings and most exciting results. Although first LHC results will be  presented there, LHC still does not have enough statistics to do the analysis that it was built to do. And this is why Tevatron and other machines try to beat it to the (possible) discovery of whatever might happen beyond the embattled Standard Model.

So far, there are several hints of something new. As with hints reported previously,  most of them will disappear with more experimental statistics – or with improved analyses. But who knows… maybe some of them will stay. It would be interesting to see if some of those hints are dispelled at this year’s ICHEP.

What are those hints, you’d ask? Well, here are some of them, in no particular order,

1. D0 semileptonic CP-asymmetry (aka “the toe of God” as New York Times has reported). An interesting, although somewhat strange result from D0 collaboration at Fermilab spurred a small waterfall of papers trying to explain it (here is the combination of older CDF and newer D0 results). If it happens to be true, we indeed would see a manifestation of New Physics in Bs oscillations. A cute thing about the above-mentioned article in New York Times is that they interviewed theorists who do not work on CP-violation in heavy quark physics…

2. MINOS mass differences measured for for neutrinos and antineutrinos (CPT-violation, anyone?). The neutrino mass differences and antineutrino mass differences measured by MINOS collaboration, showed quite a difference (see blue and red contours on this picture). Now, of course, contours overlap — and, statistically speaking, there is probability that those mixing parameters are the same. But it is a nice hint for something interesting. Now, I must say that the fact that neutrinos oscillate (and have mass) IS the biggest (and proven) hint for physics beyond the Standard Model.

3. CDF’s unexpectedly large forward-backward asymmetry in top-quark pair production. This is an interesting problem — while in QCD one expects top quark production angle to be symmetric with respect to beam direction at the lowest order, one can get a small, forward backward asymmetry (the quantity that compares the number of top quarks moving for or against a given direction) at next-to-leading order. This asymmetry is predicted to be of the order of 5%, while CDF sees something of the order of 19% with very good error bars. To make the  situation more interesting, top quark production cross section is consistent with theory. Axigluon, anyone? Maybe not…

4. Abundant Dark Matter search “anomalies”, in particular, the seasonal variation of a signal measured by DAMA collaboration. Some “older news” also include CDMS “two-event” result, PAMELA positron flux excess, etc…

Anyone’s taking bets?

P.S. I refuse to include Higgs discovery rumors in the list of possible hints, especially since they are reported by BBC and CNN (and properly dispelled by CDF and D0)!

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