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Below is a single, combined markdown table for the invts (now dis_*) variables.

  • Three columns:
    1. Variable (dis_*)
    2. Definition (code snippet or formula in plain text)
    3. Physical Meaning
  • The Comments column is omitted per your request.
Variable (dis_*)DefinitionPhysical Meaning
Electron–Ion Invariants
twopdotk2 * PIncident_Vertex.Dot(kIncident_Vertex)Scalar product (times 2) of ion 4-momentum and incident electron 4-momentum
s_eMIon^2 + mElectron^2 + twopdotkTotal squared energy (Mandelstam s) of the electron–ion system
Virtual Photon
twopdotq2 * PIncident_Vertex.Dot(qVirtual_Vertex)Scalar product (times 2) of ion 4-momentum and virtual photon 4-momentum
s_qMIon^2 + twopdotqModified CM energy squared, replacing electron with virtual photon
Core DIS Kinematics
q2Q2 = Q2Max * uu + Q2Min * (1 - uu)Negative four-momentum transfer squared (Q^2) of the virtual photon
xBjxBj = (xMin)^(1 - uv) * (xMax)^(uv)Bjorken-x, fraction of the target nucleon’s momentum carried by the struck quark
x_dx_d = xBj * (MProton / MIon)Rescaled x to account for the ion’s mass
y_dy_d = q2 / (x_d * twopdotk)Inelasticity parameter in ion-level kinematics
Yplus1 + (1 - y_d) * (1 - y_d)Common DIS factor 1 + (1-y)^2 in the generator’s notation
Proton (Ion) Momentum
pDrestsqrt( PIncident_Rest(0)^2 + PIncident_Rest(1)^2 + PIncident_Rest(2)^2 )Magnitude of the proton/ion 3-momentum in its own rest frame
Missing Mass
MX2PX_Vertex.M2()Squared invariant mass of the unobserved (remaining) hadronic system
Spectator Kinematics
alphaSABeam * ( pS_rest * csThRecoil + pSpectator_Rest.E() ) / MIonLight-cone momentum fraction of the spectator/recoil nucleon or baryon
pPerpSpS_rest * sqrt( 1 - csThRecoil * csThRecoil )Transverse momentum of the spectator in the rest frame
Miscellaneous
nuE_incident_e - E_scattered_e (or similar)Energy transfer from the electron to the hadronic system
t_spectator, tprime(p_in - p_recoil)^2, and tprime = t - t_min (not explicitly in snippet)Momentum transfer to the spectator or “excess” above minimal t
tempvar(placeholder variable)Debug or intermediate quantity, often zero
  • Units:

    • Most energy and momentum quantities are in GeV, and squared forms (like s_e, s_q, q2, MX2) are in GeV^2.
    • Dimensionless variables include xBj, x_d, alphaS, y_d, Yplus.
  • Notes:

    • Variable naming in code was invts.TwoPdotk, etc. You have them as dis_twopdotk, etc.
    • The definitions come directly from the MC generator snippet you provided.

Released under the MIT License.