Talk:Neutrinoless double beta decay

Read and enjoyed it

I enjoyed reading the article! I especially liked the clarity of the sentences and the overall structure of the article - and I learned how to incorporate a quote :-) --Hexapol (talk) 15:04, 17 July 2020 (UTC)

Observations and suggestions for improvements

The following observations and suggestions for improvements were collected, following expert review of the article within the Science, Tecnology, Society and Wikipedia course at the Politecnico di Milano, in June 2020.

General structure of the article It can be ok, but at least change the title of sec.2.2 to make clear the content, e.g. “Overview of 0vbb decay theory”

Scientific Quality. Several misleading/missing concepts should be addressed. Some examples in the following:

• Multiple references to the Majorana nature of the neutrino can be found. This is appropriate, but the subject should be better exaplained, starting from the fact that we are talking about neutral, massive, spin ½ particles, for which different possible descriptions can be given, leading to the concept of so called “Dirac” or “Majorana” neutrinos etc (see also below)
• “Weak beta decays normally produce one electron (or positron), emit an antineutrino (or neutrino) and increase the nucleus' proton number Z….” Here the words in parenteses refer to beta+, compared to beta-. This should be explicit and, in addition, it is necessary to add (decrease) after increase
• “The nucleus' mass (i.e. binding energy)…” This is wrong. It should be e.g. “mass (which is given by the mass of the constituents nucleons minus the binding energy)”. The link to binding energy is not useful in this context: a much more useful one would be to: https://en.wikipedia.org/wiki/Semi-empirical_mass_formula
• “There exists a number of elements that can decay into a nucleus of lower mass, but they cannot emit one electron only because the resulting nucleus is kinematically (that is, in terms of energy) not favorable (its energy would be higher).” This important sentence is not very clear and, in addition, a very important aspect would be to clarify when this situation for a double-beta decay is energetically possible. One could add, e.g. “This situation occurs only for a pair of even-Z, even-N isobars (with Z1=z2+-2) with a higher-mass intermediate odd-Z, odd-N isobar, as a direct consequence of the nuclear pairing energy (again reference to the above page). This would be useful also to understand why the nuclei mentioned in section 3 have these properties.
• “The electrons will be emitted back-to-back due to momentum conservation.[12]” it would be useful to add something like “with a specific energy spectrum, different if compared with the one characterizing the conventional double-beta decay”

Comments to the text.

Intro.

The very first sentence should be aboslutely clear in stressing that we are talking about a physical process which can spontaneusly take place in nature, which is theoretically conceived and proposed but not experimentally found (maybe yet). I don’t know whether this could sound clear to the non-specialized public.

I would definitely make reference to the experimentally verified conventional 2beta decay starting from the intro, to put the entire subject of the article into proper perspective. In addition, I would be careful in introducing the notion of Majorana vs Dirac.

Sec.1

By keeping as most as possible the original text, I would change in:

The Italian physicist Ettore Majorana first introduced the concept of a particle having spin ½ and non-zero mass being its own antiparticle.[6] Particles' nature was subsequently named after him as Majorana particles. Back in 1939, Wendell H. Furry proposed the idea of the Majorana nature of the neutrino, which was associated with beta decays.[8] Furry stated the transition probability to even be higher for the neutrinoless double beta decay.[8] It was the first idea proposed to search for the violation of lepton number conservation.[1] It has, since then, drawn attention to it for being useful to study the nature of neutrinos (see quote). Indeed, The neutrinoless double beta decay is one method to search for the possible Majorana nature of neutrinos.[5]. The theory of double beta decay was investigated by Goeppert-Mayer, Konopinsky, Primakoff and Rosen, Greuling and Whitten (REF can be made to Chapt. 5.2 of the classic textbook “Beta Decay” by Wu and Moszkowski, where refers to these papers can be found)

Sec 2

Consider the above comments, relevant for revising important aspects of sections 2.1 and 2.2.

Majorett (talk) 10:43, 25 July 2020 (UTC)