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The recently discovered sharp peak in the excitation function of the K+/pi+ratio around 30 A GeV in relativistic heavy-ion collisions is discussed in theframework of the Statistical Model. In this model, the freeze-out of an idealhadron gas changes from a situation where baryons dominate to one with mainlymesons. This transition occurs at a temperature T = 140 MeV and baryon chemicalpotential mu(B) = 410 MeV corresponding to an energy of sqrt(s) = 8.2 GeV. Thecalculated maximum in the K+/pi+ ratio is, however, much less pronounced thanthe one observed by the NA49 Collaboration. The smooth increase of the K-/pi-ratio with incident energy and the shape of the excitation functions of theLambda/pi+, Xi-/pi+ and Omega/pi ratios all exhibiting maxima at differentincident energies, is consistent with the presently available experimentaldata. The measured K+/pi+ ratio exceeds the calculated one just at the incidentenergy when the freeze-out condition is changing.  We speculate that at this point freeze-out might occur in a modified way. Wediscuss a scenario of an early freeze-out which indeed increases K+/pi+ ratiowhile most other particle ratios remain essentially unchanged. Such an earlyfreeze-out is supported by results from HBT studies.Comment: 8 pages, 5 figures, SQM2006 conference, Los Angeles, March 200

Transition from baryon-to meson-dominated freeze-out—early decoupling around 30AGeV?