A Measurement of the Cross Section for Four Pion Production in Yy Collisions at Spear*
نویسندگان
چکیده
We present a measurement of the cross section for the reaction e+e-f e+e-?r'rr-7;frat SPEAR. This channel is found to be large and dominated by the process yy + pop0 + -+-t-frTrTTr. The cross section, which is small just above the four pion threshold, exhibits a large enhancement near the p ' ' p threshold. * Work supported in part by Department of Energy, contracts DE-AC03-76SF00515 and W-7405-ENG-48, by the Universitat Bonn, Federal Republic of Germany, the Centre d'gtudes Nucleaires de Saclay, France and the Miller Institute for Basic Research in Science, Berkeley, California Present addresses: + Vanderbilt University, Nashville, TN 37235 tt DESY, Hamburg, Fed. Rep. of Germany $ EP Division, CERN, Geneva, Switzerland t+ c l'f a 1 ornia Institute of Technology, Pasadena, CA 91125 . . f Harvard University, Cambridge, MA 02138 Universitat Bonn, Fed. Rep. of Germany a CEN-Saclay, France. s LPNHE, Ecole Polytechnique, Palaiseau, France. (Submitted to Physics Letters B)
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