A summary Mw-Mt plot for Christmas 2006 January 5, 2007Posted by dorigo in news, physics, science.
I suppose that the heavy machinery of global electroweak fits is at work at this very moment, to produce an updated blue band plot and a new estimate of the Higgs boson mass. I am unfortunately out of the loop, so I cannot broadcast here any first-hand information on what the new estimate of the Higgs boson mass is – but I guess it will not move much from the 85 GeV estimate of Summer 2006: probably the added information will kick it down by a couple GeV or so. You can always check the status of global fits at the LEP electroweak working group web page, http://lepewwg.web.cern.ch/LEPEWWG/ .
What I can do for you today is to show a couple of plots, which just summarize the status of top and W mass measurements together with the Standard Model fits predictions. Here is the by now famous “MtMw” plot:
As you see, the new CDF measurement does not add dramatically more information: indeed, the world average for Mw is more precise than CDF measurement alone, as the plot below shows clearly. However, the hints at a light higgs boson are growing.
Bear in mind that there is quite a bit of magic entering into this plot. For one thing, a indirect measurement of the W boson mass performed with neutrino scattering experiments computing the rate of neutral and charged current interactions comes out low, and inconsistent with all other determinations (except maybe the L3 one): that one result has been excluded from averages, but it is a somewhat arbitrary choice which, if reverted, would drive the blue ellipse in the plot above quite a bit down.
Anyway here is the new CDF measurement compared to previous determinations and to the current world average:
UPDATE: something’s wrong with the first plot above. See the first comment to this post.