1. Name Autor | Ort und Datum technische universität dortmund 1 Original groups observed in NC reactions a sharp peak in t- dependence, which they called coherent scattering. The peak in neutrino scattering is a manifestation (reflection) of the diffractive peak in pion- nucleus elastic scattering.

2. Name Autor | Ort und Datum technische universität dortmund 2 Faissner Figure 3

3. Name Autor | Ort und Datum technische universität dortmund 3 (i) It is argued thet for Q²= a few m π ², i.e. Q² < 0.12 to 0.15 GeV² the reaction is determined by PCAC (Long tradition Adler, Faissner-Rein-Sehgal,...)‏ (ii) For ν²>> Q² the lepton current takes the divergence of the hadronic current ------> replace W +target by pion +target. The two conditions give the following formulas

4. Name Autor | Ort und Datum technische universität dortmund 4  For elastic pion-Nucleus scattering the process takes place, at a much smaller rate, even when the wavelength coreesponding to t is smaller than the nucleus.  Example: Q^2/GeV^2 SQRT (tmin) 1/[SQRT(tmin)] 0.02 0.02 GeV 10.0 Fermi 0.04 0.03 6.6 0.06 0.04 5.0 0.10 0.06 3.33  t max=0.07 GeV^2 wavelength = 0.77 fermi for all these values there is elastic scattering

5. Name Autor | Ort und Datum technische universität dortmund 5