Abstract
We show that a quark-diquark model previously introduced to explainSU(6) violations in quasi-two-body reactions is also able to accomodate a (quantitative) interpretation of the negative charge radius of the neutron, provided one uses appropriate hypotheses for the confinements (c.q. sizes) of the quarks and diquarks involved. They effectively imply the existence of a nucleon core (i.e. a massive two-quark state of substantial spatial clustering) with zero spin and zero isospin.
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The assumptions (21) can only be approximately true. In principle they disagree with the assumption that the odd-quark coupling to the diquark is different for theI=0 and for theI=1 diquark. A priori one should therefore also expect different odd-quark confinement quantities. However, the difference between 53° and 45° is presumably small enough so as not to exclude the approximation contained in assumptions (21)
To be more precise with Γ=53°, and assumptions (21) and (24), the Eqs. (22) and (23) require\(\left\langle {r^2 } \right\rangle _{D_O } \simeq 0.07{\rm{ }}R^2\) at a 1 SD level
The quasi-two-body results of [1] also remain valid. In terms ofinternal variables the diquark-quark wave functions used were complete descriptions of the baryon states considered anyway, even in the absence of real dynamical diquark clustering. In the latter situation it is primarily the diquark spectator assumption which becomes questionable. However as noted already in the analysis of [1] the spectator assumption could in principle have two (distinct) dynamical origins; one is real spatial clustering; the other a ‘filter’ resulting from the limitation of looking at peripheral quasi-two-body reactions only. The charged nucleonradii results suggest that the first mechanism is present in theI=0 diquark case while the latter one is at work for theI=1 two-quark states
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R. Carlitz: Phys. Lett.58B, 845 (1975)
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Dziembowski, Z., Metzger, W.J. & Van de Walle, R.T. Diquark clustering and the neutron charge radius. Z. Phys. C - Particles and Fields 10, 231–238 (1981). https://doi.org/10.1007/BF01549731
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DOI: https://doi.org/10.1007/BF01549731