The Δ 1232 Baryon

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(It is recommended that readers read the following introduction before reading this page: click here.

The following short note linked herein contains one paragraph proving that QCD has been constructed on the basis of an erroneous argument. click here.

The following article explains why the ground state of the Δ++, Δ- and Ω- baryons can be explained by ordinary quantum mechanical laws and without using the color variable. click here.

In the following lines it is shown how the regular charge-monopole theory discussed in this site can explain the rather low energy level of the Δ1232 baryons. Towards this end, the general analogy with atomic spectroscopy is used together with the large quantum of the elementary unit of the magnetic monopole charge.

The Δ 1232 baryon is an even parity state with a total angular momentum J=3/2 and an isospin I=3/2. The I=3/2 is completely symmetric. Therefore the spatial + spin part of the quarks' wave function must be completely antisymmetric. Hence, the symmetry of its quantum mechanical state is analogous to that of an atom/ion having 3 electrons. In atomic spectroscopy, quantum mechanics explains Hund's rule. This rule states that a symmetric spin state of electrons (and a completely antisymmetric state of the spatial part of the wave function) takes a lower energy level, relative to other states of the same configuration. The reason for the validity of Hund's rule is that in a completely antisymmetric spatial state, the exchange integral increases the binding energy of the system. An analogous effect is seen in the energy levels of the He atom, where the binding energy of a triplet state is greater than that of the corresponding singlet state. For a presentation of the He atomic energy levels, Click here.

The system of three quarks attracted by the baryonic core is analogous but spin dependent interactions are much stronger.* Thus, considering the rather high value of the magnetic monopole quantum g (where g2 is probably two orders of magnitude larger then e2 ≈ 1/137), one expects that the value of the exchange integral is quite large.

Now let us examine a term of the full wave function of the Δ1232 baryon, where all the three valence quarks are in an s-wave and their radial excitation is 0,1,2, respectively. The spins of the three quarks are parallel (and symmetric). The radial excitations increase the energy of the state, but each of the three pairs of quarks yields an exchange integral of the completely antisymmetric spatial part of the wave function. Here each of these exchange integrals decreases the energy of the state. Therefore, it is not unreasonable to find that the lowest energy level of the Δ baryons is around 1232 MeV.

In principle, one may increase the Hilbert space and use a basis containing more than one configuration. For reading an example containing some functions in a jj coupling scheme Click here.


*Here the jj coupling may be better than the LS coupling. However, this point does not destroy the qualitative arguments presented here.