# Is there an experimental technique for specifically producing Delta minus baryons and clearly detecting the products of their decay?

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Formerly I thought that Delta minus baryon was discovered in cosmic rays. However I was mistaken. Wikipedia says that Delta states were "established experimentally at the University of Chicago cyclotron and the Carnegie Institute of Technology synchro-cyclotron in the mid-1950s using accelerated positive pions on hydrogen targets" and gives two references:

[1] H. L. Anderson, E. Fermi, E. A. Long, and D. E. Nagle, “Total Cross Sections of Positive Pions in Hydrogen.” Phys. Rev., 85, 936 (1952). and ibid. p. 934.

[2] J. Ashkin et al., “Pion Proton Scattering at 150 and 170 MeV.” Phys. Rev., 101, 1149 (1956).

Robert Cahn and Gerson Goldhaber in their book "The Experimental Foundations of Particle Physics" give the same references (see pages 99-113). However pions of various signs on hydrogen targets can produce $$\Delta^{++}$$, $$\Delta^{+}$$ and $$\Delta^{0}$$ particles only according to the following formation and decay reactions: $$\begin{gather} \pi^{+}+p\to\Delta^{++}\to\pi^{+}+p,\tag{1}\\ \pi^{0}+p\to\Delta^{+}\to\pi^{0}+p,\tag{2}\\ \pi^{-}+p\to\Delta^{0}\to\pi^{-}+p.\tag{3} \end{gather}$$ The matter is that J. Beringer et al. (2012): in Particle listings $$\Delta$$(1232) do not provide any specific data for $$\Delta^{-}$$.

The $$\Delta^{-}$$ particles could be created by means of the reaction $$$$\pi^{-}+n\to\Delta^{-}\to\pi^{-}+n.\tag{4}$$$$ However, pure neutrons do not constitute a dense matter in order to form a target. They exist in the form of radiation emitted from nuclear reactors. Being neutral, neutrons cannot be compressed into dense beams. Therefore it is very difficult to implement the reaction (4) as well as to register and identify the neutron in its products.

If we use a deuterium target, then we would have two competing reactions: the reaction (4) and the following reaction $$$$\pi^{-}+p\to\Delta^{0}\to\pi^{0}+n,\tag{5}$$$$ both producing neutrons. So, is there an experimental technique for producing $$\Delta^{-}$$ baryons and clearly detecting the products of their decay? If not, this means that the data for $$\Delta^{-}$$ lifetime in Wikipedia are not experimental data.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user Ruslan_Sharipov
retagged Feb 2, 2019
Welcome to SE.Physics! Since this seems to be more of a question about the history of the study of Physics, as opposed to a question about Physics itself, it might be a better fit for SE.HistoryOfScienceAndMathematics.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user Nat
I'm voting to close this question as off-topic because it's about history; according to the site consensus, those questions should be on HSM SE.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user Chair
there is this journals.aps.org/prc/abstract/10.1103/PhysRevC.28.2064 which discusses delta- and might have references to original. needs access to a library and all these old articles need to dig in.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user anna v
The question isn't about the way in which the particle was produced. Yes, it mentions the process, but the explicit question in the end (and the only question in the whole body) is "Who first experimentally observed that?" That's just history, not physics.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user Chair
My question is about physics. I suspect that $\Delta^{-}$ is a white spot in experimental particle physics and I would like to make sure that it is really so.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user Ruslan_Sharipov
I'm voting to re-open this question, because the current revision (v8) is more clearly about the negative delta resonance itself rather than its history. Also, I agree with the asker that the lumping-together of the delta charge states in the literature is annoying.

This post imported from StackExchange Physics at 2019-02-02 19:53 (UTC), posted by SE-user rob

If you have library access try this https://www.sciencedirect.com/science/article/abs/pii/S0370157399001088 , maybe there will be references

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