Dilepton spectra from decays of light unflavored mesons

Abstract

The invariant mass spectrum of the e + e − and µ + µ − pairs from decays of light unflavored mesons with masses below the φ(1020)-meson mass to final states containing along with a dilepton pair one photon, one meson, and two mesons are calculated within the framework of the effective meson theory.The results can be used for simulations of the dilepton spectra in heavy-ion collisions and for experimental searches of dilepton meson decays.

Studies of Light Pseudoscalar Mesons at BESIII

“…The branching ratio was determined as B(η → π + π − e + e − ) = (2.11 ± 0.12 ± 0.14) × 10 −3 . It is in good agreement with previous measurements [15] as well as theoretical predictions [14]. The latter also holds for the differential mass distributions of the di-pion and the di-lepton systems.…”

γ*N→N*(1520) form factors in the timelike regime

“…The dilepton decay rate is obtained from the relation (3.1). Using the compact notation Γ ≡ Γ e + e − N , one can calculate the dilepton decay rate [39,40] as…”

Perspectives of production in , and Be reactions at SIS energies

“…We, furthermore, discard e + e − production from the scalar mesons f 0 , a 0 as advocated in Ref. [34] since our studies in Ref. [50] have indicated that the multiplicity of scalar mesons in pp reactions is very small in the energy regime of interest.…”

“…[29,33] and it was shown that the dilepton invariant mass spectra from pp reactions in the energy range from 1 -5 GeV could be rather well described within the standard sources of hadronic Dalitz and direct decays when including also the 'subthreshold' production of ρ-mesons by baryonic resonances 1 . It has been, furthermore, argued that additional channels (like dilepton decays of scalar mesons (a 0 , f 0 ) or four-body final states decays like η ′ → π + π − e + e − , (ρ 0 , ω) → π + π − e + e − , (ρ 0 , ω) → ηπ 0 e + e − ) might contribute to the elementary yield in pp and pd reactions [34]. Thus it is indispensible, that also these elementary reactions have to be measured again with high resolution in order to understand more accurately the e + e − radiation mechanisms.…”