Roper resonance excitation in hadron interactions

Roper resonance N*(1440) (1/2,1/2^+), discovered in piN-phase analysis in 1964, isn't still properly understood, in spite of its intensive study in different reactions. During last 40 years this object was sometimes announced to be an artifact, and sometimes it was discovered several neighbor resonances instead of the broad one. The new interest of Roper resonance was appear in 2003, after observation the exotic 5qTheta+ baryon in (К^+n), (К^0р)systems. In Jaffe and Wilczek model в+ is interpreted as a bound state of the spin-less ud-diquarks and s. Its lightest partner in multiplet is , |ud||ud|d which has the nucleon quantum numbers. This state can be identified as Roper resonance N*(1440)P_11.
In this article the review of the attempts to understand the Roper resonance properties in the single approach is done. The experimental studies of Roper resonance by projectiles with different quantum numbers ore analyzed. The special attention is payed to the reactions with the isoscalar projectiles (d, аlpha) and to the polarization observables (Ayy, Ay).

Document number: 2005-24/790

Authors: A.A.Yershov, L.I.Sarycheva, L.V.Malinina


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