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Issues in light hadron spectroscopy

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Il Nuovo Cimento A (1965-1970)

Summary

A high priority in light spectroscopy is to seek out and characterize various types of non-\((Q\bar Q)\) meson. The large quantity of new data now appearing will present a great opportunity. To identify the non-\((Q\bar Q)\) intruders one needs to know the regular\((Q\bar Q)\) pattern well; whole meson families thus become a target for close investigation. A powerful discovery strategy is to observe the same meson in a variety of reactions. Because mesons appear as resonances, other dynamics can distort the signal in a particular decay channel. Unitarity is the master principle for co-ordinating various sightings of the same resonance. Much of the new spectroscopic information in prospect will come from inferring two-body dynamics from three-body final states. Conventional methods of analysis via the isobar model use approximations to unitarity that need validation. Of all the meson families, the scalars should be a prime hunting ground for non-\((Q\bar Q)\)’s. Even before the advent of the new results, some revisions of the «official» classifications are urged. In particular, it is argued that the lightest broadI=0 scalar is a very broad f0 (1000). One unfinished task is to decide whether f0 (975) and a0 (980) are alike or different; several non-\((Q\bar Q)\) scalar scenarios hinge on this. To settle this, much better data on\(K\bar K\) channels is needed.

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  1. Rutherford Appleton Laboratory, Chilton, OX11 OQX, Didcot, Oxon, UK

    D. Morgan

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Morgan, D. Issues in light hadron spectroscopy. Nuov Cim A 107, 1883–1902 (1994). https://doi.org/10.1007/BF02823583

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PACS 12.38

PACS 01.30.Cc

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