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/lepton2p2h [ Modules ]

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NAME

module lepton2p2h

PURPOSE

Do all the internals for 2p2h scattering:

EM:

  • ell N1 N2 --> ell' N1' N2' == gamma* N1 N2 --> N1' N2'
  • ell N1 N2 --> ell' N Delta == gamma* N1 N2 --> N Delta

NC:

  • nu N1 N2 --> nu' N1' N2'
  • nu N1 N2 --> nu' N Delta

CC:

  • nu N1 N2 --> ell- N1' N2' (sum of hadronic charges increases by +1)
  • nu N1 N2 --> ell- N Delta ( -- " -- )

antiEM, antiNC and antiCC are the same as EM, NC, CC.

cases 1 - 3 give parametrizations for 2p2h part of structure function W1 in terms of Q^2, no distinction for neutrinos and antineutrinos

Cases 1 and 2 are those in: Lalakulich Gallmeister Mosel PRC86(2012)014614 Case 3 gives a reasonable description of MiniBooNE dd neutrino data

cases 4 - 5 give parametrization for MEC part of W1 from Christy and Bosted In this case also W3 is related to W1 (acc. Martini and Ericsson)

Case 4 describes double-differential data from MiniBooNE for neutrino and antineutrino scattering. It also describes the dd inclusive Xsection for neutrinos from T2K.


lepton2p2h/ME_Version [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

indicate the type of matrix element parametrisation

SOURCE

  integer, save :: ME_Version = 4

NOTES

possible values:

  • 1: const ME_Norm_XX ! const for CC fitted to MiniBooNE is 1.8e-6
  • 2: constant transverse and decreasing with Enu
  • 3: "Dipole transverse" transverse, fall with Q2 as 4-th power
  • 4: MEC from E. Christy (8/2015), with parametrization for longitudinal
  • 5: MEC from Bosted arXiV:1203.2262, with parametrization for longitudinal
  • 6: MEC additional parametrization, with parametrization for longitudinal
  • not yet implemented


lepton2p2h/ME_Norm_QE [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Overall strength of 2p2h matrix element with 2N out

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_Norm_QE    = (/1.0, 1.0, 1.0/)

NOTES

The value == 1 gives the coded strength


lepton2p2h/ME_Norm_Delta [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Overall strength of 2p2h matrix element with NDelta out

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_Norm_Delta = (/1.0, 1.0, 1.0/)

NOTES

The value == 1 is a dummy value


lepton2p2h/ME_Mass_QE [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Cutoff-mass in some parametrizations of 2p2h matrix element for NN out

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_Mass_QE    = (/1.0, 1.0, 1.0/)

NOTES

The value == 1 is a dummy value


lepton2p2h/ME_Mass_Delta [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Cutoff-mass in some parametrizations of matrix element for NDelta out

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_Mass_Delta = (/1.0, 1.0, 1.0/)

NOTES

The value == 1 is a dummy value


lepton2p2h/ME_Transversity [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Parametrisation of structure functions

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_Transversity = (/1.0, 1.0, 1.0/)

NOTES

The value = 1 chooses structure function W2 so that 2p2h is pure transverse


lepton2p2h/ME_LONG [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Parametrization of structure functions

for (EM,CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_LONG = (/0.0, 0.0, 0.0/)

NOTES

The value = 0 turns any additional longitudinal contribution to structure funct. W2 off


lepton2p2h/ME_W3 [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Overall strength factor for structure function W3

only for (CC,NC)

SOURCE

  real,dimension(1:3), save :: ME_W3 = (/0.,1.0, 1.0/)

NOTES

overall strength parameter for structure function W3


lepton2p2h/ME_ODW [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

switch for choosing the connection between structure functions W1(electron) and W1(neutrino) and W3(neutrino):

  • 1: for expressions from Martini et al
  • 2: for expressions from O'Connell et al
  • 3: for expression with relativistic version of O'Connell

only for (CC,NC)

SOURCE

  integer, save :: ME_ODW = 1

NOTES

  • O'Connell et al: PR C6 (1972) 719
  • Martini et al: PR C80 (2009) 065501


lepton2p2h/inmedW [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Controls which inv mass W is used in parametrization of 2p2h W1

SOURCE

  integer, save :: inmedW = 1

NOTES


lepton2p2h/T [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

target isospin, affects only neutrino 2p2h structure function

SOURCE

  real, save ::  T = 0

NOTES

  • T = 0, 1 , ...
  • T = 99 gives T = (N-Z)/2


lepton2p2h/Adep [ Global module-variables ]

[ Top ] [ lepton2p2h ] [ Global module-variables ]

PURPOSE

Switch for A-dependence of 2p2h structure function

SOURCE

  integer, save ::  Adep = 2

NOTES

  • 1: A-dependence for zero-range force (Mosel, Gallmeister, 2016)
  • 2: linear A-dependence, normalized to C12


lepton2p2h/readInput [ Subroutines ]

[ Top ] [ lepton2p2h ] [ Subroutines ]

NAME

subroutine readInput


lepton2p2h/Lepton2p2h [ Namelists ]

[ Top ] [ lepton2p2h ] [ Namelists ]

NAME

NAMELIST /Lepton2p2h/

PURPOSE

Includes parameters for 2p2h events:


lepton2p2h/lepton2p2h_DoQE [ Subroutines ]

[ Top ] [ lepton2p2h ] [ Subroutines ]

NAME

subroutine lepton2p2h_DoQE(eN,outPart,XS)

PURPOSE

Do all the electron induced 2p2h-QE scattering gamma* N1 N2 -> N1' N2'

INPUTS

OUTPUT

  • type(particle), dimension(:) :: OutPart -- the two produced nucleons
  • real :: XS -- the cross section


lepton2p2h/lepton2p2h_DoDelta [ Subroutines ]

[ Top ] [ lepton2p2h ] [ Subroutines ]

NAME

subroutine lepton2p2h_DoDelta(eN,outPart,XS)

PURPOSE

Do all the electron induced 2p2h-QE scattering gamma* N1 N2 -> N Delta

INPUTS

OUTPUT

  • type(particle), dimension(:) :: OutPart -- the two produced hadrons
  • real :: XS -- the cross section


lepton2p2h/lepton2p2h_SelectN2 [ Subroutines ]

[ Top ] [ lepton2p2h ] [ Subroutines ]

NAME

subroutine lepton2p2h_SelectN2(eN)

PURPOSE

Finds the second nucleon for the 2p2h collision

INPUTS

OUTPUT

NOTES

  • The seond particle is generated analytically, not by selecting a testparticle from the real particle vector.
  • This is at a very basic level. You may add more sophisticated features as eq. two-particle correlatione etc.
  • A threshold check Wfree>(2*mN+1MeV) is performed


lepton2p2h/lepton2p2h_FinalState [ Subroutines ]

[ Top ] [ lepton2p2h ] [ Subroutines ]

NAME

subroutine lepton2p2h_FinalState(eN,outPart,DoQE,flagOK)

PURPOSE

Generate the final state of the electron 2p2h event


lepton2p2h/lepton2p2h_XS [ Functions ]

[ Top ] [ lepton2p2h ] [ Functions ]

NAME

real function lepton2p2h_XS(eN,outPart,DoQE)

PURPOSE

calculate the electron induced 2p2h-QE cross section

INPUTS

  • type(electronNucleon_event) :: eN -- electron-Nucleon event info
  • type(particle),dimension(:) :: OutPart -- the outgoing particles
  • logical :: DoQE -- .true. for NN final state, .false. for N Delta

OUTPUT

  • the function value

NOTES


lepton2p2h_XS/ME_Dipole_transverse [ Functions ]

[ Top ] [ lepton2p2h_XS ] [ Functions ]

NAME

real function ME_Dipole_transverse(eN)

PURPOSE

calculate the 2p2h matrix element according to W_1(g_munu -q_um q_nu /Q2) * L^munu so that the contribution is only to the transverse part

NOTES

You have full access to all incoming and outgoing particles:

  • eN%lepton_in -- incoming lepton
  • eN%nucleon -- incoming nucleon 1
  • eN%nucleon2 -- incoming nucleon 2

exchanged boson:

  • eN%boson -- exchanged boson

even without considering the final state particles, you know the kind of process via 'eN%idProcess', which may take the values EM,NC,CC and also antiEM,antiNC,antiCC


lepton2p2h_XS/ME_W1W2W3 [ Functions ]

[ Top ] [ lepton2p2h_XS ] [ Functions ]

NAME

real function ME_W1W2W3(eN)

PURPOSE

to calculate the 2p2h contribution to the inclusive cross sections for electrons and neutrinos, cross section depends on all 3 structure functs

NOTES

You have full access to all incoming and outgoing particles:

  • eN%lepton_in -- incoming lepton
  • eN%nucleon -- incoming nucleon 1
  • eN%nucleon2 -- incoming nucleon 2

exchanged boson:

  • eN%boson -- exchanged boson

even without considering the final state particles, you know the kind of process via 'eN%idProcess', which may take the values EM,NC,CC and also antiEM,antiNC,antiCC