Closer to the Top

Fermilab have announced evidence for the single top quark. In the blogosphere, Tommaso Dorigo and Tony Smith have recently discussed single top production at D0. The parameter determined was the Vtb, which lies between 0.68 and 1.0. This is consistent with the Standard Model, which predicts the blue line in the diagram.

In other news today, a story on sea level rise, which may be more imminent than many appreciate. There were also some nice pictures in New Scientist last week from Antarctica.

Update 16.12: Tommaso has some further cautionary comments to make about the D0 diagram above.


6 Responses so far »

  1. 1

    mrigmaiden said,

    12 14 06

    Now that is exciting news!

  2. 2

    Kea said,

    Yes!! For a while, the painfully slow verification of the accuracy of the Standard Model over decades felt like watching a mountain grow, but nowadays it feels more like waiting for the pebble that will finally cause the avalanche.

  3. 3

    quantum diaries survivor said,

    “use with caution”
    That subscript should be used in connection with the plot above, which shows three cross section determinations that are 90 to 95% correlated among each other.

    D0’s evidence is at 3.4 sigma, but their expected sensitivity was only 2.1 sigma. So, in other words, they could claim evidence only because they measured a upward fluctuation from the standard model prediction. Or, put in still another way: D0 could not both claim evidence and measure anything but a higher-than-expected cross section for single top production…


  4. 4

    quantum diaries survivor said,

    … and indeed this inspired me into writing about the plot in my own blog… see


  5. 5

    Kea said,

    Thanks a lot, Tommaso! Your comments are very helpful. I will take a look at your blog.

  6. 6

    quantum diaries survivor said,

    Sure…And thanks for the link!

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