A1 Kinematics Calculator

Usage

This Java applet calculates the kinematics for selected A1 reactions.

If you see the picture, you can start to define your kinematics. You can choose a value for

E₀ the initial electron beam energy [MeV]
q² the photon fourmomentum transfer [GeV²/c²]
W the total center of mass energy [MeV]
θ_CMS the center of mass in plane production angle [°]

with the scrollbars. For production via an intermediate state you can also choose

Mass_X the mass of the intermediate state [MeV/c²]
θ_decay the decay angle in the rest system of X, in respect to the direction of X [°].

A red window indicates an error, e.g. production below threshold or negativ electron energy etc. Watch the status line for more information.

Some Reactions

H(e,e'p)π⁰	We investigate threshold π⁰ production as tests of chiral perturbation theory. With polarized beam and proton polarimeter, this reaction is also well suited to investigate the N->Δ transition (Nucleon deformation).
H(e,e'n)π⁺	Measure the axial form factor of the Proton.
D(e,e'd)π⁰ H(e,e'p)η	More threshold reactions to verify (or falsify ;-) ) chiral perturbation theory.
D(e,e'p)n	Electro disintegration of deuteron.
p(e,e'p)γ	Virtual Compton Scattering.
¹²C(e,e'[Δ->p,π^-])¹¹C	Choose (e,e'Resonance)... to define this reaction. With triple coincidence we can clearly separate the ¹¹C ground state and tag the Delta production via the mass of the p-pi subsystem.
³He(e,e' p p)n	Choose (e,e'Resonance)... to define this reaction, define the p p sub system as resonance (just for kinematics, of course). Triple coincidence experiment for ³He breakup. We gain information about 2 nucleon correlations.
³He(e,e' p)x	Choose (e,e'Resonance)... to define this reaction, take D + gamma as decay particles to access the complete Emiss/Pmiss range.
¹²C(e,e'[ρ->π⁺,π^-])¹²C	Choose (e,e'Resonance)... to define this reaction.

Some more Definitions

E	Energy of incoming electron
E'	Energy of outgoing electron
θ_e	Scattering angle
q²	Fourmomentum transfer q² = - 4 E E' sin²(θ_e/2)
ε	Photon polarization parameter ε = (1 - 2 (ω²-q²)/q² tan²(θ_e/2))^-1
ω	Energy transfer ω = E - E'
q	Momentum transfer (momentum of the virtual photon)

E₀	the initial electron beam energy	[MeV]
q²	the photon fourmomentum transfer	[GeV²/c²]
W	the total center of mass energy	[MeV]
θ_CMS	the center of mass in plane production angle	[°]

Mass_X	the mass of the intermediate state	[MeV/c²]
θ_decay	the decay angle in the rest system of X, in respect to the direction of X	[°].