Coherent Elastic Neutrino-Nucleus Scattering Energy Transfer What is the meaning of coherent elastic in "coherent elastic neutrino-nucleus scattering"? What I understand is when a high energy particle such as neutrino interact with the nucleus as a whole, the neutrino energy is not transferred to the target nucleus. In the meanwhile, the nucleus will recoil thus the recoil energy created (phonon). If the energy is not being transferred, then how nucleus gain the recoil energy?
 A: 
If the energy is not being transferred, then how nucleus gain the recoil energy?

Elastic  scattering is defined in the center of mass not to have any transfer of energy between the particles.:

Elastic scattering is a form of particle scattering in scattering theory, nuclear physics and particle physics. In this process, the kinetic energy of a particle is conserved in the center-of-mass frame, but its direction of propagation is modified (by interaction with other particles and/or potentials). Furthermore, while the particle's kinetic energy in the center-of-mass frame is constant, its energy in the lab frame is not.

The recoil is seen in the lab frame.
A: Elastic here basically just means that the nucleus is in the same state before and after the interaction. That is to say there are no additional neutrons/protons in an excited state, and the nucleus doesn't lose/gain any particles, or anything else like that. The nucleus is just getting pushed around it's not being otherwise modified.
A higher energy neutrino will interact inelastically by causing some neutrons/protons to be ejected from the nucleus, leaving the nucleus's state changed.
