Recent COMPASS results and future prospects for ALICE
The COMPASS Collaboration has accumulated the world’s highest statistics on the reaction π{sup −} p → π{sup +}π{sup −}π{sup −} p at 190 GeV/c. The results, presented in Section 1, show that a new state J{sup PC} = 1{sup ++} state never reported before, the a{sub 1}(1420), decaying to f{sub 0}(980)π followed by f{sub 0}(980) → ππ. In addition, the Collaboration reports an exotic J{sup PC} = 1{sup −+} state, the π{sub 1}(1600), which cannot be a quarkonium. Both states are likely to be a tetra-quark, i.e. qq{sup ¯}+qq{sup ¯} or a gluonic hybrid, a qq{sup ¯} object with an excited gluon inside it. Section 2 is devoted to a brief discussion of the central production of resonances, which is being investigated by both COMPASS and ALICE collaborations. However, the results are not yet released, so it is limited to a broad discussion of the central production, with emphasis on different analyses dictated by differences in the experimental setup.