Spectra of muons and electrons in the #betta##betta→μ# anti μe anti e reaction

The differential cross section of the reaction #betta##betta# → μ anti μe anti e is found at high energy of photons #betta#sub(1,2) >> msub(μ): dσ/depsilonsub(μ)depsilonsub(e)5.17nb/#betta#sub(1)#betta#sub(2)[[1-1.37x(1-x)][1-1.74y(1-y)]+(#betta#1 reversible #betta#2)], where x=epsilonsub(μ)/#betta#sub(1), y=epsilonsub(e)/#betta#sub(2). This reaction may be used as a convenient calibration process for determination of the luminosity of accelerators with colliding #betta##betta# beams. The results obtained give also the Born approximation cross section of the #betta##betta# → Q anti Qq anti q reaction in which two pairs of heavy quarks are produced, provided msub(Q)sup(2) >> msub(q)sup(2) >> 1 GeV2