Precision electroweak physics by ATLAS

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mfb
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Precision electroweak physics by ATLAS

Post by mfb » Fri Jan 27, 2017 9:28 pm

Two nice recent measurements from ATLAS:

W+, W-, Z cross sections (7 TeV) - with an uncertainty of just 0.6% and 0.3% for W and Z, respectively, and with many precise differential cross section values. The additional luminosity uncertainty of 1.9% is dominant, but not that relevant for the main result: The proton has a strong sea quark contribution from strange-quarks.

This sea quark contribution is the largest uncertainty in the W mass measurement, where ATLAS reached the precision of the best Tevatron result already (0.025% uncertainty) - with further improvements they will probably beat the previous world average. Reaching that so early was quite unexpected. While the previous world average was a bit higher than the electroweak fit based on other measurements, the new measurement is right in between the old measurements and the prediction. The SM fits again.

The improved strange sea quark measurement will probably allow updates of a few older measurements and help future measurements, theory predictions and MC generators.

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chelle
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Re: Precision electroweak physics by ATLAS

Post by chelle » Sat Jan 28, 2017 10:17 am

The W electroweak gauge boson was discovered in 1983 at the CERN SPS collider. Although the properties of the W boson have been studied for more than 30 years, precise measurement of its mass remains a major challenge.
So now over more than 30 years of doing 'research' they came up with these results. :roll:

Go figure, in 1983 Apple come out with the Lisa, now 30 years later they have the iPhone 7.

The latter is called scientific advancement, the former is collecting dust.
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mfb
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Re: Precision electroweak physics by ATLAS

Post by mfb » Sat Jan 28, 2017 7:13 pm

Can you just go somewhere else if you don't want to contribute anything?

Measuring the properties more precisely is harder than adding more transistors to a chip.

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chelle
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Re: Precision electroweak physics by ATLAS

Post by chelle » Sat Jan 28, 2017 11:48 pm

mfb wrote:Can you just go somewhere else if you don't want to contribute anything?
Uh, you made your contribution, I expressed an opinion, isn't that how this thing works, chatting about science … anyone can join in.

BTW I can understand that refining the measurement is an achievement, but on a scientific level it isn't teaching us anything significant, and considering the time span nothing but dull bookkeeping.
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mfb
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Re: Precision electroweak physics by ATLAS

Post by mfb » Tue Jan 31, 2017 10:45 pm

but on a scientific level it isn't teaching us anything significant
Or you just don't understand the significance because you have no idea about particle physics (something you really like to demonstrate often). How can you expect to contribute to a scientific discussion that way?

The measurements, especially the W mass, had a big impact, and ATLAS got a lot of praise for the precision achieved.

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CharmQuark
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Re: Precision electroweak physics by ATLAS

Post by CharmQuark » Thu Feb 02, 2017 6:12 pm

Hello :)

Let's keep it civilised guys :thumbup: ;)
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.

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chelle
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Re: Precision electroweak physics by ATLAS

Post by chelle » Thu Feb 02, 2017 7:12 pm

CharmQuark wrote:Hello :)

Let's keep it civilised guys :thumbup: ;)
It sure ain't me who's ending civilisation. :mrgreen:

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