jump to navigation

New zoom in on the Higgs mass from Summer 2008 Tevatron results! July 31, 2008

Posted by dorigo in news, physics, science.
Tags: , , , , ,
comments closed

Many thanks to Sven Heinemeyer, who provided me this morning with a fresh update of the traditional plot summarizing the status of Standard Model measurements of top quark and W boson masses, their consistency with SM and SUSY, and their impact on the Higgs boson mass. Have a look at it below (a better version, in .eps format, is here):

As you can see, the consistency between direct determinations at the Tevatron (blue ellipse) and the LEP II(black lines) and LEP I/SLD results (hatched purple lines) is still quite good.

One detail worth mentioning: when plotting a 68% CL ellipse atop a 68% interval, the interval will look more restrictive in the variable which is measured (in the case of blue and black lines, the W boson mass, which is in the Y axis), because of the need of the ellipse to extend way past the 1-sigma limits to accommodate a total area of 68%.

The Tevatron results on the W mass are no worse than the LEP II ones by now – and they are based on only one experiment -CDF- analyzing a twentieth of the currently available data! The W mass reach of CDF is estimated at 15 MeV, a result three times better than the current one.

So, there is still a lot to squeeze from Tevatron data, despite the update you are looking at now “only” includes an improved measurement of the top quark mass, which now sits at 172.4 +-1.2 GeV – a 0.7% accuracy on this important parameter of the Standard Model.

It remains me to congratulate with my colleagues in CDF and D0 for their continuing effort. Well done, folks!

UPDATE: a commenter asks for the 95% CL ellipse in the plot above. I advise him and whomever else wants much more information to visit Sven’s site.

Also, two other blogs have posted today discussing this result: Lubos Motl and Marco Frasca. NB: Lubos advertises his blog in the comment section below, and he says he did a much better job than me in discussing the new results… I believe him: I wrote mine with my kids running around, asking me to finally leave for a hike on the mountains. I believe Lubos has no kids so… Enjoy!