[Hybrid baryons] s-p-wave interference

[burkert]

Hi all,

At the last hybrid meeting we had some discussion on s-p-wave interference.
I attached a slide that hopefully helps clarifying this aspect.

Any J^P =1/2^+ and J^P =1/2^- terms that overlap in energy will 
interfere and generate in the Legendre expansion shown on the slide a 
term that is proportional to cos(theta). In the example shown (from our 
CLAS publication Phys.Rev. C78 (2008) 045209; arXiv:0804.0447 [nucl-ex] 
; Phys.Rev. C77 (2008) 015208 , arXiv:0709.1946 )
the interference of the Roper P11 p-wave multipoles (S1-, M1-) with 
s-wave multipoles (E0+, S0+) from the N(1535) and non-resonant terms 
generates a strong cos(theta) term, half of which is due to the resonant 
Roper contribution (difference between solid and dotted lines). Of 
course, at this Q^2 the Roper is a large amplitude and contributes to 
the total cross section also strongly, but that is not the case at some 
smaller Q^2 where the interference term is essential in extracting the 
Roper contribution.

Any comments on this are appreciated.

Cheers,
Volker


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/hybrid_baryons/attachments/20150719/271c358c/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: s-p-wave-interference.pptx
Type: application/x-visnetwork
Size: 284703 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/hybrid_baryons/attachments/20150719/271c358c/attachment-0001.bin>