Physicists make most precise measurement of neutron’s lifetime
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Re: Physicists make most precise measurement of neutron’s lifetime
#2> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino.
> ...detected sparks of light each time a neutron decayed.
Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
Re: Physicists make most precise measurement of neutron’s lifetime
#3> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino. > ...detected sparks of light each time a neutron decayed. Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
Yes, the decay will also release some energy in the form of photons but they didn't mention it.
Re: Physicists make most precise measurement of neutron’s lifetime
#4> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino. > ...detected sparks of light each time a neutron decayed. Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
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Re: Physicists make most precise measurement of neutron’s lifetime
#5Stupid question, do they account for speed dilation on the beam experiment? The difference in lifetime will translate to 50k km/s speed of neutrons or roughly 1/6c
Re: Physicists make most precise measurement of neutron’s lifetime
#6> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino. > ...detected sparks of light each time a neutron decayed. Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
No, they don't measure decays.
They let the neutrons decay for a while and then measure all the remaining neutrons in the trap by lowering there a detector.
This detector has a scintillator so when a neutron is captured it emits some photons and those are converted to an electric signal.
So no. There is no requirement for the neutron to emit an additional photon during the decay that is measured
Re: Physicists make most precise measurement of neutron’s lifetime
#7> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino. > ...detected sparks of light each time a neutron decayed. Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
Yes, the decay will also release some energy in the form of photons but they didn't mention it.
That's inaccurate, please see my reply to the same comment
Re: Physicists make most precise measurement of neutron’s lifetime
#8> Neutrons in beams seem to live longer on average
Isn’t this due to relativistic effects? What percentage of the speed of light are these beams?
Re: Physicists make most precise measurement of neutron’s lifetime
#9Stupid question, do they account for speed dilation on the beam experiment? The difference in lifetime will translate to 50k km/s speed of neutrons or roughly 1/6c
From skimming the review paper from OP (the "source:" in the caption on that error-bar chart), the neutrons in the beam experiments are thermalized, to a mean velocity of ~2,200 m/s. So, slower than 1e-5 c.
https://doi.org/10.3390/atoms6040070
(Thermal meaning the neutrons scatter lots of times against atoms in a solid material, until they reach thermal equilibrium. ~km/s is a typical Boltzmann velocity for atom-size things at room temperature).
(Not a domain expert).
Re: Physicists make most precise measurement of neutron’s lifetime
#10> [isolated neutrons] decay into protons. During the process, each decaying neutron emits an electron and an antineutrino. > ...detected sparks of light each time a neutron decayed. Detecting a spark of light would also require photon(s) to be emitted, right? Is this not called out because it is a byproduct of the decay and not part of the decay reaction itself?
Yes, the decay will also release some energy in the form of photons but they didn't mention it.
Neutron decay does not produce photons. Rather, the energy difference is carried as kinetic energy by the resulting proton, electron and (anti)neutrino. This can cause light to be emitted (very shortly) later when those particles slam into things, but as sharikous notes that doesn't seem to be they're talking about here.