E896 has measured $\Lambda$ production in $11.6A\mathrm{GeV}/c$ Au-Au collisions over virtually the whole rapidity phase space. The midrapidity $p_t$ distributions have been measured for the first time at this energy and appear to indicate that the $\Lambda$ hyperons have different freeze-out conditions than protons. A comparison with the relativistic quantum molecular dynamics model shows that while there is good shape agreement at high rapidity the model predicts significantly different slopes of the $m_t$ spectra at midrapidity. The data, where overlap occurs, are consistent with previously reported measurements.

• Received 8 May 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.062301