Total cross section of two-photon production of hadrons

• DOI: 10.1007/bf01597557
• Publication Date: 2005-04-29T02:08:56Z
• Authors: S. E. Baru; M. V. Beilin; A. E. Blinov; V. E. Blinov; A. E. Bondar; A. D. Bukin; S. I. Eidelman; Yu. I. Eidelman; V. R. Groshev; V. A. Kiselev; S. G. Klimenko; G. M. Kolachev; S. I. Mishnev; A. P. Onuchin; V. S. Panin; V. V. Petrov; I. Ya. Protopopov; A. G. Shamov; V. A. Sidorov; Yu. I. Skovpen; A. N. Skrinsky; V. A. Tayursky; V. I. Telnov; A. B. Temnykh; Yu. A. Tikhonov; G. M. Tumaikin; A. E. Undrus; A. I. Vorobiov; V. N. Zhilich; A. A. Zholents
• Keywords: Multiplicity (mathematics); Momentum transfer; Electron–positron annihilation; Invariant mass

The total cross section for γγ→hadrons was measured as a function of the invariant massW of the system (1.25 to 4.25 GeV) at thee+e−-collider VEPP-4 with the detector MD-1. For the first time the data were obtained by detecting both scattered leptons with almost zero emission angles. The mean squared four momentum transfer 〈q2〉 is −0.005 GeV2, the rmsW resolution is 100–250 MeV. The data on the mean charged multiplicity 〈nC〉 are well described by the function 〈nC〉=(1.62 ±0.37)+(1.83±0.45)·ln(W(GeV)). TheW dependence of the total cross section is consistent with the theoretical prediction σ(nb)=240+270/W(GeV).