Recoilless resonant absorption of Mossbauer antineutrinos: A relook at experimental possibilities with low Q electron capture isotopes

We present a detailed relook at the possibility of observing recoilless resonant absorption of a Mossbauer antineutrino emitted during the electron capture (EC) decay of a parent nucleus by a target nucleus of the corresponding daughter isotope. The possibility of observing a Mossbauer effect for antineutrinos via a bound state β-decay or through EC was proposed within a few years after the discovery of the Mossbauer effect for gamma emission. However, bound state β-decay systems like the H³- He³ were found to be unfeasible due to low phonon less-emission probabilities, homogeneous and inhomogeneous line broadening and binding energy variations of the He³ embedded in a metal matrix. Alternative EC isotopes like the Ho¹⁶³- Dy¹⁶³ were also suggested that could lead to feasible experiments. But producing controlled high purity  Ho¹⁶³- Dy¹⁶³ are a technological challenge. Lately other easily producible isotopes like the Fe⁵⁷- Mn⁵⁷ have been considered for the observation of Mossbauer effect. Low Q EC isotopes like the  Se⁷⁵- As⁷⁵ have also come to the fore due to the interest in neutrino mass measurements. Here we consider the  feasibility of Fe⁵⁷- Mn⁵⁷ and the Se⁷⁵- As⁷⁵  based experiments for observing Mossbauer antineutrinos after considering known phonon lattice dynamics, homogenous and in homogenous line broadening, relativistic effects and magnetic moments at the site of emission and absorption. We will discuss experimental geometries that could enhance the possibility of observing Mossbauer antineutrinos.