TABLE OF CONTENTS
- 1. /XsectionRatios
- 1.1. XsectionRatios/flagScreen
- 1.2. XsectionRatios/ScreenMode
- 1.3. XsectionRatios/flagInMedium
- 1.4. XsectionRatios/InMediumMode
- 1.5. XsectionRatios/flagVacEL
- 1.6. XsectionRatios/flagVacHRES
- 1.7. XsectionRatios/flagVacMesProd
- 1.8. XsectionRatios/alpha
- 1.9. XsectionRatios/beta
- 1.10. XsectionRatios/shift0
- 1.11. XsectionRatios/getSigmaScreened
- 1.12. XsectionRatios/getSigmaTotal
- 1.13. XsectionRatios/accept_event
- 1.14. XsectionRatios/init
- 1.15. XsectionRatios/XsectionRatios_input
- 1.16. XsectionRatios/Ratio
- 1.17. XsectionRatios/Ratio_BaB
- 1.18. XsectionRatios/RatioNNPion_NN
/XsectionRatios [ Modules ]
NAME
module XsectionRatios
NOTES
Computes and stores the ratios of the in-medium and vacuum BB -> BB + mesons cross sections (see M. Wagner et al., PRC 71, 034910 (2005).
XsectionRatios/flagScreen [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
logical, save :: flagScreen = .false.
PURPOSE
- If .true. -- in-medium screening is applied to the input cross section.
- If .false. -- no cross section modification.
NOTES
flagScreen should be replaced by flagInMedium
XsectionRatios/ScreenMode [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
integer, save :: ScreenMode = 1
PURPOSE
possible values:
- 1: in-medium screening of NN total cross section according to Li and Machleidt, PRC 48 (1993) 1702 and PRC 49 (1994) 566
- 2: in-medium screening of BB total cross section according to P. Daniewlewicz, NPA 673, 375 (2000); Acta. Phys. Pol. B 33, 45 (2002)
NOTES
relevant when flagScreen = .true.
XsectionRatios/flagInMedium [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
logical, save :: flagInMedium = .false.
PURPOSE
- If .true. -- In-medium ratios are used to decide whether an event is accepted or not.
- If .false. -- The event is always accepted
XsectionRatios/InMediumMode [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
integer, save :: InMediumMode = 2
PURPOSE
possible values:
- 1: all events of the type BB -> BB (+ mesons) are subject to in-medium reduction following Eqs.(194),(195) of GiBUU review paper [currently works in RMF mode only]
- 2: NN -> NN elastic scattering events are modified according to Li and Machleidt all other BB -> BB (+ mesons events are subject to in-medium reduction according to Eq. (33) from T. Song, C.M. Ko, PRC 91, 014901 (2015) [works in all modes (Skyrme, RMF, cascade)]
NOTES
relevant when flagInMedium = .true.
XsectionRatios/flagVacEL [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
logical, save :: flagVacEL = .false.
PURPOSE
- If .true. -- no in-medium modification for NN -> NN elastic
NOTES
relevant for flagInMedium = .true.
XsectionRatios/flagVacHRES [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
logical, save :: flagVacHRES = .false.
PURPOSE
- If .true. -- no in-medium modification for BB <-> BB with at least one participating resonance higher than P33(1232) or with more than one P33(1232)
NOTES
relevant for flagInMedium = .true.
XsectionRatios/flagVacMesProd [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
logical, save :: flagVacMesProd = .false.
PURPOSE
- If .true. -- no in-medium modification for BB -> BB + meson(s)
NOTES
relevant for flagInMedium = .true.
XsectionRatios/alpha [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
real, save :: alpha = 1.2
PURPOSE
Parameter which controls the density dependence of the NN <-> N Delta cross section via suppression factor of exp(-alpha*(rho/rho_0)**beta)
for the density dependence from: Song/Ko, arXiv:1403.7363 (InMediumMode=2)
XsectionRatios/beta [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
real, save :: beta = 1.
PURPOSE
Parameter which controls the density dependence of the NN <-> N Delta cross section via suppression factor of exp(-alpha*(rho/rho_0)**beta)
for the density dependence of the type of arXiv:2107.13384 (InMediumMode=2)
XsectionRatios/shift0 [ Global module-variables ]
[ Top ] [ XsectionRatios ] [ Global module-variables ]
SOURCE
real, save :: shift0 = 0.
PURPOSE
Mass shift m-m^* (GeV) for using in elementary particle collision mode.
XsectionRatios/getSigmaScreened [ Functions ]
[ Top ] [ XsectionRatios ] [ Functions ]
NAME
real function getSigmaScreened(pair,sigma,srts,mediumAtColl)
PURPOSE
Returns in-medium screened/reduced cross section (mbarn). See:
- Li and Machleidt, PRC 48 (1993) 1702 and PRC 49 (1994) 566,
- P. Daniewlewicz, NPA 673, 375 (2000); Acta. Phys. Pol. B 33, 45 (2002)
INPUTS
- type(particle), dimension(1:2) :: pair -- incoming particles
- real, intent(in) :: sigma -- not screened cross section
- real, intent(in) :: srts -- c.m. energy
- type(medium), intent(in) :: mediumAtColl -- medium info
NOTES
srts and mediumAtColl only needed for ScreenMode=1
XsectionRatios/getSigmaTotal [ Functions ]
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NAME
real function getSigmaTotal(pair)
PURPOSE
Returns the total in-medium cross section (mbarn).
INPUTS
- type(particle), dimension(1:2) :: pair -- incoming particles
NOTES
The total in-medium pp cross section is used for all types of colliding baryons/antibaryons.
Returns zero if there is at least one incoming meson.
XsectionRatios/accept_event [ Functions ]
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NAME
logical function accept_event(pair,finalState)
PURPOSE
Accepts or rejects the event randomly, using the in-medium cross section ratios:
- returns .true. --- if the event is accepted
- returns .false. --- if the event is rejected
INPUTS
- type(particle), dimension(1:2) :: pair -- incoming particles
- type(particle), dimension(:) :: finalState -- outgoing particles
NOTES
the procedure is as follows: first, a particle collision is chosen with the default cross sections. Then, in a second step, the ratio of the in-medium and the vacuum cross section is calculated. If smaller than 1, then the event generated in step 1 is rejected by a Monte Carlo decision.
XsectionRatios/init [ Subroutines ]
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NAME
subroutine init
PURPOSE
Reads in input switches from namelist XsectionRatios_input.
XsectionRatios/XsectionRatios_input [ Namelists ]
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NAME
NAMELIST /XsectionRatios_input/
PURPOSE
Includes the switches:
- flagScreen
- ScreenMode
- flagInMedium
- InMediumMode
- flagVacEL
- flagVacHRES
- flagVacMesProd
- alpha
- beta
- shift0
XsectionRatios/Ratio [ Functions ]
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NAME
real function Ratio(srtsStar,mStar,mass)
PURPOSE
Compute the ratio of the in-medium and vacuum B_1 + B_2 -> B_3 + B_4 + M_5 + M_6 + M_7 + M_8 cross sections
INPUTS
- real :: srtsStar -- c.m. energy (GeV),
- real dimension(:) :: mStar -- Dirac masses of all particles (GeV)
- real dimension(:) :: mass -- vacuum masses of all particles (GeV)
OUTPUT
NOTES
The particles 1 and 2 are incoming baryons, the particles 3 and 4 are outgoing baryons, the particles M_5, ..., M_8 are outgoing mesons. The routine will compute one of the ratios:
- B_1 + B_2 -> B_3 + B_4,
- B_1 + B_2 -> B_3 + B_4 + M_5,
- ...,
- B_1 + B_2 -> B_3 + B_4 + M_5 + ...+ M_8
depending on the the size n of the arrays mStar and mass, which must be in the interval [4:8].
XsectionRatios/Ratio_BaB [ Functions ]
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NAME
real function Ratio_BaB(pair,finalState)
PURPOSE
Compute the ratio of the in-medium and vacuum cross sections baryon + antibaryon -> mesons
INPUTS
- type(particle), dimension(1:2) :: pair -- incoming particles
- type(particle), dimension(:) :: finalState -- outgoing particles
OUTPUT
NOTES
Maximum 6 mesons can be treated (otherwice returns Ratio_BaB=1.).
XsectionRatios/RatioNNPion_NN [ Functions ]
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NAME
real function RatioNNPion_NN(nucleon1,nucleon2,pionPart)
PURPOSE
Compute the ratio of the in-medium and vacuum absorption rates N1 N2 pi --> N3 N4
INPUTS
- type(particle), intent(in) :: nucleon1,nucleon2,pionPart
OUTPUT
- real :: RatioNNPion_NN -- ratio of the in-medium and vacuum absorption rates