Observables

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	A_00b0	A_000t	A_00bt
Scattered particle polarization	P_s000	D_s0b0	K_s00t	M_s0bt
Recoil particle polarization	P_0r00	K_0rb0	D_0r0t	N_0rbt
Spin correlation of the final state	C_sr00	C_srb0	C_sr0t	C_srbt

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.