Two classes of interesting results this morning from the EuroPhysics conference. I’ll try to explain their significance later when time permits.
- The LHC experiments ATLAS and CMS put new and much stronger limits on certain classes of supersymmetric theories. [However, other types of supersymmetry are not very constrained by these measurements; so the end of supersymmetry is by no means nigh, despite what you may read elsewhere.]
- The Tevatron’s DZero experiment repeated the CDF measurement of the top quark forward-backward asymmetry. [In the proton-antiproton collisions of the Tevatron, top quarks are more likely to head in the proton direction than in the antiproton direction; this tendency is much larger than expected.] Like CDF, DZero sees an excess 2 standard deviations above the Standard Model prediction, although unlike CDF they do not see significant variation of the asymmetry with the total energy of the event [more precisely, with the top-antitop invariant mass]. This excess asymmetry remains the most significant experimental disagreement with the predictions of the Standard Model. But it is still far from convincing.