The proton is a tiny particle with a neutron to form the nucleus of atoms. It turns out that these protons are smaller than previously thought. New measures of the Paul Scherrer Institute in Switzerland as the radius of the proton give a value of 0.84184 femtómetros (an equivalent to a milbillónesima femtómetro of a meter), 4% smaller than previous measured values. (For comparison, the thickness of a sheet of paper in relation to the radius of the Earth does not matter that the radius of the proton in relation to the thickness of the sheet.) does not seem much but it has important implications for physics. You can imagine how extremely difficult it is to measure the size of something so tiny.
The experiment to calculate the range consisted of a hydrogen gas in which electrons are exchanged atoms for muons. A muon is a particle very similar to the electron but 200 times heavier. The important thing here is that they have exactly the same load. It can acquire the site of the electron (driving it) in a hydrogen atom is stabilized by electrostatic interaction between the positively charged nucleus and negatively charged muon. Due to the greater weight of the muon orbits - their way of moving in an atom - are altered compared to the electron. And this change in the movement as accurate a measure faciliti.
In an excited atom, the muon is in an orbit with higher energy orbit in part, its preferred state. Eventually decays, this means that the muon orbit pass high to low, driving down the road a photon. The energy of this photon has the same energy as the difference between the two levels. In addition, energy is characteristic for the proton-muon system and depends on the radius of the proton. By detecting the energy of these photons the researchers could calculate the radius of the proton, which turned out to be smaller than they had expected.
Although a difference of only 4 percent of the above measures not enough, has implications for physics. Unfortunately, even the scientists themselves know the origin of this discrepanica. Maybe the theories used is no longer accurate enough and require further adaptation. Or end up not fully understanding the nature of the muon and the way they interact with the proton. This is one of those cases where en un deja más prequntas experiment by challenging them to solve it originally querían.
The experiment to calculate the range consisted of a hydrogen gas in which electrons are exchanged atoms for muons. A muon is a particle very similar to the electron but 200 times heavier. The important thing here is that they have exactly the same load. It can acquire the site of the electron (driving it) in a hydrogen atom is stabilized by electrostatic interaction between the positively charged nucleus and negatively charged muon. Due to the greater weight of the muon orbits - their way of moving in an atom - are altered compared to the electron. And this change in the movement as accurate a measure faciliti.
In an excited atom, the muon is in an orbit with higher energy orbit in part, its preferred state. Eventually decays, this means that the muon orbit pass high to low, driving down the road a photon. The energy of this photon has the same energy as the difference between the two levels. In addition, energy is characteristic for the proton-muon system and depends on the radius of the proton. By detecting the energy of these photons the researchers could calculate the radius of the proton, which turned out to be smaller than they had expected.
Although a difference of only 4 percent of the above measures not enough, has implications for physics. Unfortunately, even the scientists themselves know the origin of this discrepanica. Maybe the theories used is no longer accurate enough and require further adaptation. Or end up not fully understanding the nature of the muon and the way they interact with the proton. This is one of those cases where en un deja más prequntas experiment by challenging them to solve it originally querían.
Pohl, R., Antognini, A., Nez, F., Amaro, F. Biraben, F., Cardoso, J., Covita, D., Dax, A., Dhawan, S. Fernandes , L., Giesen, A., Graf, T., Hänsch, T., Indelicato, P., Julien, L., Kao, C., Knowles, P., Le Bigot, E., Liu, Y. Lopes, J., Ludhova, L., Monteiro, C., Mulhauser, F., Nebel, T., Rabinowitz, P., dos Santos, J., Schaller, L., Schuhmann, K., Schwob, C. , Taqqu, D., Veloso, J., & Kottmann, F. (2010). The size of the proton Nature, 466 (7303), 213-216 DOI: 10.1038/nature09250
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