16 June 2024


For several models you can obtain numerical values or figures of the predictions for observables, both in the CM and lab frame.

There are unfortunately many conventions and notations used for nucleon-nucleon scattering observables. A table in which they are written down for comparison and conversion is in preparation and will be available in due time.

The number of observables that NN-OnLine recognizes is currently somewhat limited, but they will all be available later.

There are two ways to select the observable you wish; the menu lists some of the most used observables, but in the textinputfield you can enter other observables as well. Case of the input is irrelevant. If you selected an observable from the menu and also typed one in the inputfield, then the latter observable will be used!

Measured quantity Unpolarized beam, Polarized beam, Unpolarized beam, Polarized beam,
unpolarized target unpolazized target polarized target polarized target
Angular distribution I0000 A00b0 A000t A00bt
Scattered particle polarization Ps000 Ds0b0 Ks00t Ms0bt
Recoil particle polarization P0r00 K0rb0 D0r0t N0rbt
Spin correlation of the final state Csr00 Csrb0 Csr0t Csrbt

The following list shows which observables NN-OnLine currently recognizes. The first column gives the code for the obervable as used in the programs.

Code    Observable

SGT     Sgt
SGTL    SgtL
SGTT    SgtT

DSG     Dsg    =  I0000           Differential cross-section
P       P                         Polarization
PB      Pb     =  Pn000 = A00n0   Polarization of the beam
PT      Pt     =  P0n00 = A000n   Polarization of the target
D       D      =  Dn0n0 
R       R      =  Ds'0s0 
RP      R'     =  Dk'0s0 
A       A      =  Ds'0k0 
AP      A'     =  Dk'0k0 
DT      Dt     =  K0nn0 
RT      Rt     =  K0s''s0 
RTP     Rt'    = -K0k''s0 
AT      At     =  K0s''k0 
ATP     At'    = -K0k''k0 
CNN     Cnn    =  Cnn00 
CKP     Ckp    =  Cs's''00 
CPP     Cpp    =  Ck's''00 
CKK     Ckk    = -Cs'k''00 
CPK     Cpk    = -Ck'k''00 
AYY     Ayy    =  A00nn 
AXX     Axx    =  A00ss 
AZX     Azx    =  A00ks 
AXZ     Axz    =  A00sk 
AZZ     Azz    =  A00kk 

Calculating proton-proton observables is the only cpu-intensive process in NN-OnLine. In general the time needed for these calculations should be at most about 10 seconds (up to 2 minutes for the 3d figures). But remember that the more you ask for - the more time the calculations will take. Response times that are much longer either mean a bug in the programs or (more likely) congestion of the net. 16 June 2024