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Scientists Calculate Most Precise Measurement of Electron's Mass
sciencehabit writes "A team of physicists has produced the most precise electron mass measurement ever made. Instead of trying to measure the mass directly, the researchers bound a single electron to a bare carbon nucleus and placed the resulting atom in a uniform electromagnetic field called a Penning trap. The team's new measurement is 13 times more precise than previous efforts, with an uncertainty of just 0.03 parts per billion. The group's precise result will help physicists more accurately calculate the fine-structure constant, an important value in tests of the standard model of particle physics, which shapes our understanding of the basic building blocks of the universe."
They determined the electron mass compared to that of a proton, so it depends on how accurate the proton mass has been determined.
...Slightly larger than a particle of commons sense, which is in such short supply these days.
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I'm puzzled where you're seeing the confusion. TFA uses the term "precise" precisely (heh) as it is meant to be used: it tells you the uncertainty (known uncertainty, obviously, though you can throw in a "fudge factor" to account for unknown factors) in the measurement. It's not really possible to tell if the measurement is *accurate* except by comparing it to other measurements made by other teams, but given the higher level of precision in this experiment, that comparison is mostly useless (I'm assuming their data with error lies within the data with error of other measurements. If it didn't, that might end being much bigger news).
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
DOIs can take a few hours/days or so to start working in some cases, if the results were recently announced. While Slashdot covering recent news would be surprising, it's not totally unheard of.
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
They have to run the test again. One of the researchers was looking at the electron when they took the measurement.
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Actually, the mass of a hydrogen atom isn't equal to the sum mass of the proton and that of the electron. There's a 13.6 eV binding energy (good 'ol E-mc^2) that needs to be taken into account. Considering that the 511 eV rest mass of the electron and the fact that we're taking about measurements that are supposed to be accurate to less than 1 part per billion, then the binding energy is pretty significant. I suspect there are other effects that also need to be taken into account.
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I'm getting a DOI not found for the paper from TFS, the DOI being 10.1038/nature13026.
Does anyone know the correct identifier?
So, the DOI is precise and you're asking if it's accurate? :-)
It must have been something you assimilated. . . .