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/resonanceCrossSections [ Modules ]

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NAME

module resonanceCrossSections

PURPOSE

Includes all routines to evaluate "baryon meson -> R -> X" cross sections with resonances R in the intermediate state.


resonanceCrossSections/fullPropagator [ Global module-variables ]

[ Top ] [ resonanceCrossSections ] [ Global module-variables ]

PURPOSE

Includes also the real parts in the resonance propagator. In former works (i.e. in the old Efffenberger code) this has been neglected. It should be set to .true. only if mediumSwitch_coll=.true. in the namelist width_Baryon.

SOURCE

  logical, save :: fullPropagator=.false.

resonanceCrossSections/ResonanceCrossSections [ Namelists ]

[ Top ] [ resonanceCrossSections ] [ Namelists ]

NAME

NAMELIST ResonanceCrossSections

PURPOSE

Includes parameters:


resonanceCrossSections/resonanceMass [ Functions ]

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NAME

real function resonanceMass(ID, charge, media, FourMomentum, position, perturbative)

PURPOSE

Determines the bare (vacuum) mass of a resonance, if its 4-momentum (effective mass) is known.

INPUTS

  • integer :: ID ! ID of resonance
  • integer :: charge ! charge of resonance
  • type(medium) :: media ! Medium at the point of the resonance
  • real :: FourMomentum(0:3) ! 4-momentum of resonance in the LRF
  • real :: position(1:3) ! position of resonance in calculation frame

RESULT

  • resonance mass in GeV

NOTES

This was known as "detmass" in the old code.


resonanceCrossSections/barMes2resonance [ Functions ]

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NAME

function barMes2resonance(idMeson_ini, idBaryon_ini, chargeMeson_ini, chargeBaryon_ini, propagated, mediumAtCollision, momentumLRF, masses, mesonMass, baryonMass, position, perturbative, srts) result (sigma)

PURPOSE

Evaluates baryon meson -> Resonance cross sections by summing over the resonances final state. One gets baryon meson -> X by summing over the (baryon meson -> R-> X) channels for all resonances.

See eq. (2.52) in Effenberger Phd.

INPUTS

  • integer :: idMeson_ini
  • integer :: idBaryon_ini
  • integer :: chargeMeson_ini
  • integer :: chargeBaryon_ini
  • logical :: propagated --- if .true., then onsider only propagated particles in final state, otherwise consider all particles in final state
  • type(medium) :: mediumAtCollision ! Medium information
  • real, dimension(0:3) :: momentumLRF ! Momentum of resonance in LRF
  • real :: mesonMass ! masses of colliding particles.
  • real :: baryonMass ! masses of colliding particles.
  • real, dimension(1:3) :: position ! Position where resonance is produced
  • logical :: perturbative ! flag for the perturbative nature of resonance
  • real, optional :: srts ! sqrt(s) of the collision -- needed in RMF mode

RESULT

  • real, dimension(Delta:nbar) :: sigma --- Cross section for each intermediate baryon resonance in units of mB. The index denotes the resonance.
  • real, dimension(Delta:nbar) :: masses --- Masses of the produced resonances; index denotes the resonance.


resonanceCrossSections/barMes_R_barMes [ Functions ]

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NAME

real function barMes_R_barMes(idMes_in, idBar_in, idMes_out, idBar_out, chargeMes_in, chargeBar_in, chargeMes_out, chargeBar_out, background, propagated, MediumAtCollision, momentumLRF, mesonMass_in, baryonMass_in, position, perturbative, srts)

PURPOSE

Evaluates contribution of resonances to baryon meson -> baryon meson according to the Breit-Wigner formula, cf. eq. (2.52) in Effenberger Phd. One gets B m -> B m by summing over the (b M -> R->b M) channels for all resonances.

INPUTS

  • integer :: idMes_in --- IDs of particles in initial state.
  • integer :: idBar_in --- IDs of particles in initial state.
  • integer :: idMes_out --- IDs of particles in final state.
  • integer :: idBar_out --- IDs of particles in final state.
  • integer :: chargeMes_in --- Charges of particles in initial state
  • integer :: chargeBar_in --- Charges of particles in initial state
  • integer :: chargeMes_out --- Charges of particles in final state
  • integer :: chargeBar_out --- Charges of particles in final state
  • logical :: background --- .true. = Compute background cross section : Therefore consider only non-propagated particles in intermediate state; .false. = Full Xsection : Consider all particles in intermediate state
  • logical :: propagated --- .true. = Consider only propagated particles in intermediate state; .false. = Consider all particles in intermediate state

Information for In-Medium modifications :

  • type(medium) :: mediumAtCollision --- Medium information at the point of collision
  • real, dimension(0:3) :: momentumLRF --- Total Momentum in LRF = Momentum of resonance in LRF
  • real :: mesonMass_in --- masses of colliding particles
  • real :: baryonMass_in --- masses of colliding particles
  • real, dimension(1:3) :: position --- Position where resonance is produced
  • logical :: perturbative --- flag for the perturbative nature of resonance
  • real, optional :: srts --- sqrt(s) of the collision, needed in RMF mode

NOTES

Note that it is not useful to set both background and propagated to .true. : Result=0.

RESULT

  • resonance contribution to baryon meson -> baryon meson (in mb)


resonanceCrossSections/sigma_npi_n2pi_resonances [ Subroutines ]

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NAME

subroutine sigma_npi_n2pi_resonances(srts,charge_iniPion,background,sigmaTotal)

PURPOSE

Evaluates contribution of resonances to proton Pion -> Nucleon Pion Pion in the VACUUUM assumption [Gamma's are not the medium modified ones] One gets pion p -> pi pi N by summing over the (pion p -> R->pion Delta), (pion p -> R-> N rho), (pion p -> R-> N sigma) and (pion p -> R-> pion P11_1440) channels. All resonances but the P_11(1440) decay fully into N pi. Therefore the final states are in the end N Pi Pi states. For the P_11(1440) the ratio of N pi pi final states is given by its decay ratio into N pi.

INPUTS

  • logical, intent(in) :: background --- .true. = Compute background cross section : Therefore consider only non-propagated particles in intermediate state; .false. = Full Xsection : Consider all particles in intermediate state
  • real, intent(in) :: srts --- sqrt(s) in the process
  • integer, intent(in) :: charge_iniPion --- charge of incoming pion

RESULT

  • real, intent(out),dimension(-2:2) :: sigmaTotal --- cross sction in mB

Meaning of index in sigmaTotal :

  • -2 : pi+ pi- in final state
  • -1 : pi0 pi- in final state
  • 0 : pi0 pi0 in final state
  • 1 : pi+ pi0 in final state
  • 2 : pi+ pi+ in final state