Talk:Isotopes of helium

message: Are the halo nuclei of 6He and 8He the reason they have relatively long half-lives, compared to the other unstable isotopes of helium? XinaNicole (talk) 23:54, 29 May 2011 (UTC)
thread_title:  Halo nuclei 

message: Should 2He (diproton) be included in the table of isotopes? Whoop whoop pull up Bitching Betty | Averted crashes 13:56, 27 July 2011 (UTC)
replies: text: I would say no because it is still hypothetical. If its existence is ever confirmed then yes. Dirac66 (talk) 14:02, 27 July 2011 (UTC)
replies: text: No, because it does not exist, and cannot, according to current theory. Plasmic Physics (talk) 14:03, 27 July 2011 (UTC)
replies: text: Thank you, but then why is it included in the table of nuclides? Whoop whoop pull up Bitching Betty | Averted crashes 14:14, 27 July 2011 (UTC)

text: It shouldn't be there either, I don't know when it got in there, but it should go. Plasmic Physics (talk) 14:19, 27 July 2011 (UTC)
replies: text: I agree that it should go, and I have continued this discussion at Talk:Table of nuclides#Remove He-2 (diproton)?. Dirac66 (talk) 15:32, 27 July 2011 (UTC)
thread_title:  Diproton in table 

message: The intro now claims (since 19 October 2011) that He-2 has a half-life of 3x10-27 sec. Where does this number come from, please? I will mark it "citation needed".
Such a short half-life would seem to violate the speed limit of the universe. The time to separate two protons by a nuclear diameter of 10-15m cannot be less than 10-15m / c = 3 x 10-24s, so the claimed half-life implies that the protons are separating at 1000 times the speed of light.
Also there is a measurement problem here. Extremely short half-lives cannot be measured directly, but are deduced from the width of some resonance. Here the width would be ħ / 10-27s = 107 J = 1 TeV. Real measured widths are much smaller than that.
If these simple arguments are incorrect for some reason, we need to see the evidence.
Also in the section on He-2, the last two paragraphs are not properly referenced. One cannot just say that "The best evidence of He-2 was found in 2008 at the Istituto Nazionale di Fisica Nucleare, in Italy." We need a  journal reference with author names, journal title with volume and pages and article title, and if possible an on-line link. Same for the Japanese and Russian work in the next paragraph. Does the 3x10-27s value come from one of these papers?? I don't know and I can't check if you don't tell me where the papers are. More "citation needed" tags. Dirac66 (talk) 14:37, 19 December 2011 (UTC)
replies: text: P.S. Neither the Nubase nor the Nudat databases list a value for He-2. Dirac66 (talk) 21:48, 24 December 2011 (UTC)
replies: text: I have now added a citation for the description of the Italian experiment. The information was hiding at Talk:Diproton. It says nothing about a half-live value or estimate. Dirac66 (talk) 15:10, 3 January 2012 (UTC)
thread_title:  Improbably short half-life for He-2 

message: Under the subtitle "Helium-2 (diproton)," the contributor suddenly introduces the name “Bradford” - as if we should all know who he is. Bradford is not a ‘Newton’ or an ‘Einstein.’ If he is not previously motioned, than his credentials should be stated to give validity to the article. At the very least, his full name (or initials) should precede his surname - try searching “Bradford” in the ‘search box.’ Manixx2a (talk) 23:46, 3 July 2012 (UTC)
replies: text: At the end of the sentence there is a little [5] leading to a footnote which gives the author's initials (R.A.W. Bradford), and the article publication details (journal, volume, date, pages and title). Try Googling R.A.W. Bradford + astrophysics. Dirac66 (talk) 01:34, 4 July 2012 (UTC)
thread_title:  Who the #&@% is "Bradford" 

message: http://hal.archives-ouvertes.fr/docs/00/17/56/14/PDF/rpp.pdf
Two-proton radioactivity - Bertram Blank ‡ and Marek P loszajczak †
Other is from RIKEN (?): http://fy.chalmers.se/~f2bmz/papers/korsheninnikov_2003_7h.pdf doi:10.1103/PhysRevLett.90.082501 p 2: "corresponds to our expectation that the two protons from the reaction p ( 8He; pp ) 7H can undergo ﬁnal state interaction being emitted as a virtual singlet state 2He. This method was used in the study of 5H in the reaction p ( 6He; pp ) 5H [1]. \n When detecting the two protons by the RIKEN telescope, we obtain kinematically complete information about these two protons and, due to energy and momentum conservation in the reaction p (8 He; pp ) 7H, we can unambiguously reconstruct a mass of the residual system 7H. Also, we detected tritons and neutrons from the breakup of 7H using a downstream detection system consisting of a dipole magnet and plastic scintillators. This part of setup was the same as in our previous experiment described in Ref. [7]."
`a5b (talk) 00:52, 19 July 2013 (UTC)
thread_title:  possible source for diproton 

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thread_title:  External links modified 

message: Generally accepted that hyperdense solar plasma (in stars) consists of intermingled electrons and nucei. At the energy and neutrino levels of solar plasma, "neutron decay" would equilibrate with neutron creation. D2 would probably turn to Deuterium by electron capture not positron emission like vacuum chamber experiments show, however Deuterium plus 1.9MeV(see neutron source wiki) is proton plus neutron (deuterium fissions). Or at solar plasma pressure is the reaction favoring Deuterium. If it does it means Deuterium >> Helium4 is a faster reaction. TaylorLeem (talk) 19:05, 27 June 2020 (UTC)
thread_title:  Solar plasma 

message: If the daughter isotope of the rarer Helium-6 decay mode is Helium-4, isn't it double neutron decay? Similarly, if the daughter isotope of the rarest decay mode of Helium-8 is Helium-5, isn't it triple neutron decay? Why are these decay modes indicating simultaneous electron/proton emission with the beta decay symbol when the only difference between the parent and daughter nuclides across these decay modes is neutron count?
As far as I'm aware, the proper format for other isotope lists is Xn, where X is number of emitted neutrons (see Isotopes of Hydrogen) - deuteron and triton emission aren't shorthand for 2n and 3n decay modes, they're a separate decay type entirely (unless I'm misunderstanding something, they're more like alpha emission; they're referring to the emission of entire deuterium and tritium nuclei). InkTide (talk) 12:21, 6 April 2023 (UTC)
thread_title:  Deuteron/triton emission  

message: The article can be found here. 2A04:CEC0:10EE:D636:ADA9:C82B:7392:6BE (talk) 11:08, 7 February 2024 (UTC)
thread_title:  A ridiculous article in 1938 that claimed a stable <sup>5</sup>He 

message: Since the decay mode of 6Be is 2p, could the two protons be considered as 2He in an instant? 2A01:E34:EC74:7170:C92D:3550:651:9FE3 (talk) 16:47, 5 May 2024 (UTC)
replies: text: Belli et al. (2019) consider 5He, 5Li, 6Be, and 8Be to be alpha emitters indeed. Double sharp (talk) 07:40, 11 May 2024 (UTC)
thread_title:  Could <sup>2</sup>He possibly occur as alpha decay product of <sup>6</sup>Be?