# Tag Archives: top mass

## CDF/D0 Combined Top Mass Result

For those of you interested in HEP in general and Higgs searches in specific, you may have already heard of the Combined CDF/D0 top mass preliminary release. They’ve changed from $170.9^+_- 1.1(sta)^+_- 1.5(sys)$ last year to $172.6^+_- 0.8(sta)^+_- 1.1(sys)$ which is a total uncertainty of 0.8%. Tommaso Dorigo has a really nice post on the individual measurements and combined uncertainties that went in to the result. There’s also a bit of general discussion on how to combine measurements and an interesting point on how top mass measurements may-or-may-not be effected by jet multiplicities in the final state. He suggests that the full luminoisty this might improve to 0.5% .

For those of you who don’t get all giggly at slightly lower error bars for their own sake, the top quark is the heaviest of the six flavors of quarks, and was first measured with certainty around 1994-5. The mass of the top is an important parameter in estimating properties of the yet-to-be-seen Higgs Boson, as well as an important input to describing the plethora of other physics processes at the LHC. If you want to know where to look for the Higgs, and you want to know what backround stuff isn’t new physics, then you want to know the top mass really really well.