![]() | Wu experiment has been listed as one of the
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good article criteria. If you can improve it further,
please do so. If it no longer meets these criteria, you can
reassess it. Review: May 10, 2020. ( Reviewed version). |
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in the text: "due to the W and Z gauge bosons of the weak interaction coupling only to left-handed matter particles and the right-handed antimatter particles". Z bosons do couple to left and right handed particles (with different strength), the charged W couples only to left-handed particles.
217.224.249.27 ( talk) 04:52, 19 January 2013 (UTC)Hallo
Nice article, but I don't entirely get it. There must be some kind of fairly simple analysis that can be given: e.g. 'if the P operator is applied to the nucleus, then one would get ..blah', etc. I don't really understand why one can look at the asymetry and deduce parity violation. There are some kind of missing steps here. User:Linas ( talk) 23:19, 30 November 2013 (UTC)
The first paragraph is unclear or contains a simple error: "it would be possible to distinguish between a mirrored version of the world and the mirror image of the current world." There are no circumstances under which one can distinguish between one thing described in two different ways, unless we are talking about distinguishing between descriptions of worlds rather than distinguishing between worlds. The options are: EITHER (1) Replace either "a mirrored version of the world" or "the mirror image of the current world" with the words "the actual world." OR (2) Explain each of the concepts clearly enough that it is possible for the reader to understand the difference between (1) and (2). — Preceding unsigned comment added by Eugene Penguin ( talk • contribs) 01:08, 4 January 2015 (UTC)
In the last paragraph of the Experiment section, it is stated that:
If the electrons were always found to be emitted in the same direction and in the same proportion as the gamma rays, P-conservation would be true. If there were a bias in the direction of decays, that is, if the distribution of electrons did not follow the distribution of the gamma rays, then P-violation would be established.
I am maybe a bit puzzled, but isn't it exactly the other way round? In the results section, it is stated that If P-conservation were true in beta decay, electrons would have no preferred direction of decay relative to the nuclear spin, which seems correct to me but contradicts the other sentence. Nilpferd1991 ( talk) 14:06, 22 October 2018 (UTC)
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Reviewing |
Reviewer: Reyk ( talk · contribs) 15:24, 6 December 2019 (UTC)
I'll review this; hope to have it finished in a week or so. It looks pretty good at first glance. Reyk YO! 15:24, 6 December 2019 (UTC) 1. Well written
2. Verifiable with no original research
4.
Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each
5. Stable: it does not change significantly from day to day because of an ongoing
edit war or content dispute
6. Illustrated, if possible, by media such as
images,
video, or
audio
Coincidentally, I was looking at the page because I wanted to know the details of Wu's experiment, and I found this review. I think the article is good, but not great. Its major weakness is that it skips over the real principle behind the experiment very quickly: there's a lot of exposition about the setup and the decay, but then what you expect to see, and crucially why, is left to a sentence or two. The diagram in "The Experiment" section that endeavours to explain the theoretical setup could also be better, or at least far better explained. I can try to add a few sentences to effect these emendations and you can judge for yourself if that's any better. Krea ( talk) 17:52, 7 December 2019 (UTC)
@ Reyk: You're welcome. I've made a few edits. I tried to incorporate the theory into the existing "The experiment" section, but I found it too unwieldy. In consequence, I've added a theory section to explain the basic idea of the experiment. I'm not sure if it's clear enough to explain to the casual reader the essential points, but that's my best attempt for what it's worth. I've gone over Wu's paper, which is surprisingly short, and I've tried to add some of the points that it makes without going into the details too much. As such, I've also made a few minor corrections and added a few points. I've also removed the diagram that I was complaining about before: I think it really doesn't help because it kind of conflates Wu's setup and the general argument for why emission anisotropy implies parity invariance. My reading of Wu's paper is that the experiment doesn't depend on reversing the polarizing field, but it does do that for experimental reasons. So, a diagram that talks about flipping the polarizing field gives an incorrect impression of the experiment. What would really be nice is a diagram like the one here: [2] (p. 7) that explains the anisotropy/P-violation idea. I'll see if I can find one that is in the public domain.
Let me know if you have any comments or criticisms on my additions or changes. Krea ( talk) 18:44, 8 December 2019 (UTC)
Thanks for the ping. I haven't forgotten about this but I've fell sick for the past few days. Should be back up on my feet within a day or two, so you can expect movement on this this week. Headbomb { t · c · p · b} 19:18, 27 January 2020 (UTC)
A comment about the timeline:
reference 4, currently used to support the statement that the experiment was carried out in December 1956
, doesn't actually state the month. It refers to a six-month work-up period
and the extraordinary jam-packed sessions
at the APS meeting in January 1957.
Lee and Yang recall, The Columbia–Bureau of Standards experiment under C. S. Wu was progressing satisfactorily during the fall of 1956. She shuttled back and forth between New York City and Washington and kept us informed of the progress of the experiment. Around Christmas she finally said they were getting an asymmetry indicating that parity was not conserved in β decay, but she warned that it was very preliminary and therefore we should not spread any rumors. We didn't, but rumors somehow were generated anyway and we answered an alarming number of phone calls asking for and/or offering information.
The
Gizmodo piece linked above omits the long build-up period prior to the December observations, and it actually links back to the Wikipedia article, which makes me leery of using it here.
In this reminiscence, Wu says that she canceled her trip in the spring of 1956 (not just before the Christmas holidays).
XOR'easter (
talk)
21:27, 16 February 2020 (UTC)
Reyk, Headbomb, where does this review stand? It's been open for nearly four months, yet as best I can tell Headbomb hasn't edited the article since December 8, two days after the review opened, but has made over 12,000 mainspace edits in 2020 alone. If Headbomb can't make time in the seven days to address the issues in this review, it's probably time to close this. Thank you. BlueMoonset ( talk) 18:17, 2 April 2020 (UTC)
The article says: equal probability in all directions. They don't have to be equal in all directions, only, as it says just a little farther down, the same for θ and pi-θ. Gah4 ( talk) 06:34, 8 October 2020 (UTC)
Why does the results section say: gamma ray anisotropy instead of beta anisotropy? Gah4 ( talk) 06:39, 8 October 2020 (UTC)
@ Krea: Sorry I'm late to the party. I only noticed today that you removed File:Wu experiment.jpg and suggested using a diagram like the one here (page 7) to explain the anisotropy/P-violation idea. I'd be happy to make a new image for you if you like. Just leave a note on my talk page. Cheers. nagual design 13:53, 16 December 2020 (UTC)
I went ahead and made the image (right). Let me know if you'd like any alterations. nagual design 22:11, 16 December 2020 (UTC)
The article says that "experiment then essentially counted the rate of emission for gamma rays and electrons in two distinct directions", when actually the gamma was measured in two directions ("polar" and "equatorial") whilst the beta only in one. The gamma measurements were used to measure the polarisation of the nuclei as its temperature changed as it warmed up from a very low temperature and the cold beta emissions compared with the warm ones. The latter differed much more than the former because of the parity violation. PeterGrecian ( talk) 11:12, 8 April 2021 (UTC)
![]() | Wu experiment has been listed as one of the
Natural sciences good articles under the
good article criteria. If you can improve it further,
please do so. If it no longer meets these criteria, you can
reassess it. Review: May 10, 2020. ( Reviewed version). |
![]() | This ![]() It is of interest to the following WikiProjects: | ||||||||||||||||||||
|
in the text: "due to the W and Z gauge bosons of the weak interaction coupling only to left-handed matter particles and the right-handed antimatter particles". Z bosons do couple to left and right handed particles (with different strength), the charged W couples only to left-handed particles.
217.224.249.27 ( talk) 04:52, 19 January 2013 (UTC)Hallo
Nice article, but I don't entirely get it. There must be some kind of fairly simple analysis that can be given: e.g. 'if the P operator is applied to the nucleus, then one would get ..blah', etc. I don't really understand why one can look at the asymetry and deduce parity violation. There are some kind of missing steps here. User:Linas ( talk) 23:19, 30 November 2013 (UTC)
The first paragraph is unclear or contains a simple error: "it would be possible to distinguish between a mirrored version of the world and the mirror image of the current world." There are no circumstances under which one can distinguish between one thing described in two different ways, unless we are talking about distinguishing between descriptions of worlds rather than distinguishing between worlds. The options are: EITHER (1) Replace either "a mirrored version of the world" or "the mirror image of the current world" with the words "the actual world." OR (2) Explain each of the concepts clearly enough that it is possible for the reader to understand the difference between (1) and (2). — Preceding unsigned comment added by Eugene Penguin ( talk • contribs) 01:08, 4 January 2015 (UTC)
In the last paragraph of the Experiment section, it is stated that:
If the electrons were always found to be emitted in the same direction and in the same proportion as the gamma rays, P-conservation would be true. If there were a bias in the direction of decays, that is, if the distribution of electrons did not follow the distribution of the gamma rays, then P-violation would be established.
I am maybe a bit puzzled, but isn't it exactly the other way round? In the results section, it is stated that If P-conservation were true in beta decay, electrons would have no preferred direction of decay relative to the nuclear spin, which seems correct to me but contradicts the other sentence. Nilpferd1991 ( talk) 14:06, 22 October 2018 (UTC)
GA toolbox |
---|
Reviewing |
Reviewer: Reyk ( talk · contribs) 15:24, 6 December 2019 (UTC)
I'll review this; hope to have it finished in a week or so. It looks pretty good at first glance. Reyk YO! 15:24, 6 December 2019 (UTC) 1. Well written
2. Verifiable with no original research
4.
Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each
5. Stable: it does not change significantly from day to day because of an ongoing
edit war or content dispute
6. Illustrated, if possible, by media such as
images,
video, or
audio
Coincidentally, I was looking at the page because I wanted to know the details of Wu's experiment, and I found this review. I think the article is good, but not great. Its major weakness is that it skips over the real principle behind the experiment very quickly: there's a lot of exposition about the setup and the decay, but then what you expect to see, and crucially why, is left to a sentence or two. The diagram in "The Experiment" section that endeavours to explain the theoretical setup could also be better, or at least far better explained. I can try to add a few sentences to effect these emendations and you can judge for yourself if that's any better. Krea ( talk) 17:52, 7 December 2019 (UTC)
@ Reyk: You're welcome. I've made a few edits. I tried to incorporate the theory into the existing "The experiment" section, but I found it too unwieldy. In consequence, I've added a theory section to explain the basic idea of the experiment. I'm not sure if it's clear enough to explain to the casual reader the essential points, but that's my best attempt for what it's worth. I've gone over Wu's paper, which is surprisingly short, and I've tried to add some of the points that it makes without going into the details too much. As such, I've also made a few minor corrections and added a few points. I've also removed the diagram that I was complaining about before: I think it really doesn't help because it kind of conflates Wu's setup and the general argument for why emission anisotropy implies parity invariance. My reading of Wu's paper is that the experiment doesn't depend on reversing the polarizing field, but it does do that for experimental reasons. So, a diagram that talks about flipping the polarizing field gives an incorrect impression of the experiment. What would really be nice is a diagram like the one here: [2] (p. 7) that explains the anisotropy/P-violation idea. I'll see if I can find one that is in the public domain.
Let me know if you have any comments or criticisms on my additions or changes. Krea ( talk) 18:44, 8 December 2019 (UTC)
Thanks for the ping. I haven't forgotten about this but I've fell sick for the past few days. Should be back up on my feet within a day or two, so you can expect movement on this this week. Headbomb { t · c · p · b} 19:18, 27 January 2020 (UTC)
A comment about the timeline:
reference 4, currently used to support the statement that the experiment was carried out in December 1956
, doesn't actually state the month. It refers to a six-month work-up period
and the extraordinary jam-packed sessions
at the APS meeting in January 1957.
Lee and Yang recall, The Columbia–Bureau of Standards experiment under C. S. Wu was progressing satisfactorily during the fall of 1956. She shuttled back and forth between New York City and Washington and kept us informed of the progress of the experiment. Around Christmas she finally said they were getting an asymmetry indicating that parity was not conserved in β decay, but she warned that it was very preliminary and therefore we should not spread any rumors. We didn't, but rumors somehow were generated anyway and we answered an alarming number of phone calls asking for and/or offering information.
The
Gizmodo piece linked above omits the long build-up period prior to the December observations, and it actually links back to the Wikipedia article, which makes me leery of using it here.
In this reminiscence, Wu says that she canceled her trip in the spring of 1956 (not just before the Christmas holidays).
XOR'easter (
talk)
21:27, 16 February 2020 (UTC)
Reyk, Headbomb, where does this review stand? It's been open for nearly four months, yet as best I can tell Headbomb hasn't edited the article since December 8, two days after the review opened, but has made over 12,000 mainspace edits in 2020 alone. If Headbomb can't make time in the seven days to address the issues in this review, it's probably time to close this. Thank you. BlueMoonset ( talk) 18:17, 2 April 2020 (UTC)
The article says: equal probability in all directions. They don't have to be equal in all directions, only, as it says just a little farther down, the same for θ and pi-θ. Gah4 ( talk) 06:34, 8 October 2020 (UTC)
Why does the results section say: gamma ray anisotropy instead of beta anisotropy? Gah4 ( talk) 06:39, 8 October 2020 (UTC)
@ Krea: Sorry I'm late to the party. I only noticed today that you removed File:Wu experiment.jpg and suggested using a diagram like the one here (page 7) to explain the anisotropy/P-violation idea. I'd be happy to make a new image for you if you like. Just leave a note on my talk page. Cheers. nagual design 13:53, 16 December 2020 (UTC)
I went ahead and made the image (right). Let me know if you'd like any alterations. nagual design 22:11, 16 December 2020 (UTC)
The article says that "experiment then essentially counted the rate of emission for gamma rays and electrons in two distinct directions", when actually the gamma was measured in two directions ("polar" and "equatorial") whilst the beta only in one. The gamma measurements were used to measure the polarisation of the nuclei as its temperature changed as it warmed up from a very low temperature and the cold beta emissions compared with the warm ones. The latter differed much more than the former because of the parity violation. PeterGrecian ( talk) 11:12, 8 April 2021 (UTC)