Coherent electromagnetic production of mu and tau lepton pairs in relativistic heavy-ion collisions

Abstract

We calculate the coherent production of muon and tauon pairs in peripheral collisions between nuclei at ultra-relativistic energies. This type of production exhibits a high degree of sensitivity to the electromagnetic structure of the nucleons in the colliding nuclei. The pair cross sections, even at high invariant masses and transverse momenta, are large on hadronic scales, and are governed by the magnitude of the nuclear and nucleon form factors at momentum transfers greater than 1 GeVc-'. We argue that this process could serve as a useful experimental probe of nuclear and nucleon form factors.

Electromagnetic heavy-lepton pair production in relativistic heavy-ion collisions

“…At RHIC energies, the τ − τ + cross section with no form factor in our work approximately is 5 times lower than in Ref. [27], however, the results with the form factor are close to each other. Our cross section results of μ − μ + rates at RHIC and LHC are about slightly lower than in Ref.…”

“…where the value of 2 is 0.71 GeV 2 [27]. We have observed that the effect of this distribution is negligible.…”

“…The potentials from nucleus 2 can be written by the substitutions, b → −b and β → −β. In the above equation f Z (q 2 ) is the form factor of a nucleus which gives the momentum distribution of a proton in the nucleus, and G E (q 2 ) is the form factor of a proton which represents the electric distribution of the proton [11,27]. As we mentioned above, we have used two parameter Fermi (2pF) function (or Wood-Saxon function) for the charge distribution of the protons:…”

The effects of nucleus form factors on the electromagnetically produced heavy lepton pairs

“…14 In the above equation, f Z (q 2 ) is the form factor of a nucleus which gives the momentum distribution of a proton in the nucleus. 9,27 In this work, we have used The effects of nucleus form factors three different charge distribution as uniform, Gaussian and Wood-Saxon(Fermi) and therefore from these distributions we obtain three different form factors in our calculations. For the uniform charged nucleus, the normalized charged distributions can be written as…”

Thirteen years of pair production

“…The above work was extended to other classes of particles (15)(16)(17) and effects from microstructure in the nuclear currents (18). Generally, electron pair production is not strongly affected by the details of the nuclear currents.…”