document: Absorption events through the charged current reactions (2)νe+40Ar→e−+40K∗andν̄e+40Ar→e++40Cl∗. There is some uncertainty in predicting e−(e+) event rates for these processes which arise due to the nuclear model dependencies of the absorption cross section and the treatment of the Coulomb distortion of electron (positron) in the field of the residual nucleus. The nuclear absorption cross section for the charged current neutrino reactions in 40Ar relevant to supernova neutrino energies was first calculated by Raghavan [10] and Bahcall et al. [11] for Fermi transitions leading to isobaric analogue state (IAS) at 4.38 MeV in 40K∗. Later Ormand et al. [12] used a shell model to calculate the Fermi and Gamow–Teller transitions. In these calculations Fermi function F(Z,Ee) was used to take into account the Coulomb effects. In a recent paper Bueno et al. [13] make use of a calculation by Martinez-Pinedo et al. [14] who use a shell model for Fermi and Gamow–Teller transitions and a continuum random phase approximation (CRPA) for forbidden transitions to calculate the absorption cross sections. In this calculation the Coulomb distortion of the produced electron is treated with a hybrid model where a Fermi function is used for lower electron energies and modified effective momentum approximation (MEMA) for higher electron energies [14–17]. In a recent work Bhattacharya et al. [18] have measured the Fermi and Gamow–Teller transition strengths leading to excited states up to 6 MeV in 40K∗ and obtained the neutrino absorption cross section for supernova neutrinos in 40Ar.
extractive_keyphrases: absorption events through the charged current reactions continuum random phase approximation coulomb effects crpa electron fermi and gamow–teller transition strengths ias isobaric analogue state mema modified effective momentum approximation neutrino absorption cross section nuclear absorption cross section for the charged current neutrino reactions nuclear model dependencies positron residual nucleus shell model supernova neutrino energies the absorption cross sections the fermi and gamow–teller transitions treatment of the coulomb distortion
abstractive_keyphrases: 4.38 mev in 40k calculation by martinez-pinedo et al. predicting e−(e+) event rates shell model for fermi and gamow–teller transitions