TABLE OF CONTENTS
- 1. /barBar_barBarMes
- 1.1. barBar_barBarMes/barBar_barBarMes
- 1.1.1. barBar_barBarMes/NNpi
- 1.1.2. barBar_barBarMes/NNpi_BG
- 1.1.3. barBar_barBarMes/NNV_BG
- 1.1.4. barBar_barBarMes/isofac_omega
- 1.1.5. barBar_barBarMes/isofac_phi
- 1.1.6. barBar_barBarMes/NN_NNpi_direct
- 1.1.7. barBar_barBarMes/Np_NRplus_NNPion
- 1.1.8. barBar_barBarMes/sstatepi
- 1.1.9. barBar_barBarMes/sig_NNV
- 1.1.10. barBar_barBarMes/chooseCharge_NNpiomega
/barBar_barBarMes [ Modules ]
NAME
module barBar_barBarMes
PURPOSE
This module implements the calculation of baryon baryon -> baryon baryon meson cross sections.
barBar_barBarMes/NNpi [ Global module-variables ]
[ Top ] [ barBar_barBarMes ] [ Global module-variables ]
SOURCE
logical, save :: NNpi = .true.
PURPOSE
Global switch for the N N -> N N pi contibution
barBar_barBarMes/NNpi_BG [ Global module-variables ]
[ Top ] [ barBar_barBarMes ] [ Global module-variables ]
SOURCE
integer, save :: NNpi_BG = 2
PURPOSE
Switch for the N N -> N N pi background (s-channel):
- 0 = no BG
- 1 = BG according to Teis
- 2 = BG according to Buss (improves threshold behavior, default)
- 3 = BG according to Weil
barBar_barBarMes/NNV_BG [ Global module-variables ]
[ Top ] [ barBar_barBarMes ] [ Global module-variables ]
SOURCE
logical, save :: NNV_BG = .true.
PURPOSE
Incude a N N -> N N V background term, where V=omega,phi (in addition to possible resonance contributions).
barBar_barBarMes/isofac_omega [ Global module-variables ]
[ Top ] [ barBar_barBarMes ] [ Global module-variables ]
SOURCE
real, save :: isofac_omega = 1.
PURPOSE
Isospin enhancement factor for p n -> p n omega, relative to p p -> p p omega. Data indicate that this is around 2, while theory predicts even larger values (up to 5). Reference: Barsov et al., EPJ A21 (2004) 521-527.
barBar_barBarMes/isofac_phi [ Global module-variables ]
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SOURCE
real, save :: isofac_phi = 1.
PURPOSE
Isospin enhancement factor for p n -> p n phi, relative to p p -> p p phi. Theory predicts values of 3-4, cf.: Kaptari, Kaempfer, Eur.Phys.J. A23 (2005) 291-304.
barBar_barBarMes/barBar_barBarMes [ Namelists ]
[ Top ] [ barBar_barBarMes ] [ Namelists ]
NAME
NAMELIST barBar_barBarMes
PURPOSE
Includes the switches:
barBar_barBarMes/NN_NNpi_direct [ Functions ]
[ Top ] [ barBar_barBarMes ] [ Functions ]
NAME
function NN_NNpi_direct(srtfree, bg) result(Sigma_NNPion)
PURPOSE
Returns the background contributions to NN-> NN pion (via non-propagated resonances, plus non-resonant part).
It contain the following channels:
- 1: p p -> p p pi^0 ; which is equivalent to n n -> n n pi^0
- 2: p n -> n n pi^+ ; which is equivalent to p n -> p p pi^-
- 3: p n -> p n pi^0 ;
- 4: p p -> p n pi^+ ; which is equivalent to n n -> p n pi^-
INPUTS
- real :: srtfree --- sqrt(s) in GeV
OUTPUT
- real, dimension (1:4) :: Sigma_NNPion --- cross sections in mB
barBar_barBarMes/Np_NRplus_NNPion [ Subroutines ]
[ Top ] [ barBar_barBarMes ] [ Subroutines ]
NAME
subroutine Np_NRplus_NNPion(srtS, background, ch, sigmaDelta, sigma1_2, sigma3_2)
PURPOSE
Evaluates the cross sections for N p -> N Resonance(+) -> N N pion with vacuum assumptions. It returns the cross sections sigma1_2, which is summed over all I=1/2 resonances in the intermediate state, and sigma3_2, which is summed over all I=3/2 resonances in the intermediate state.
INPUTS
- real :: srts -- sqrt(s)
- logical :: background -- .true. : do not consider any propagated resonances, therefore the background contribution is returned; .false. : Consider all resonances, therefore the full resonance contribution is returned
- integer :: ch -- charge of incoming nucleon
OUTPUT
- real :: sigmaDelta -- cross section contribution of Delta
- real :: sigma1_2 -- cross section summed over all I=1/2 resonances
- real :: sigma3_2 -- cross section summed over all I=3/2 resonances (except the Delta)
barBar_barBarMes/sstatepi [ Functions ]
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NAME
function sstatepi(srts, choice) result(sigma)
PURPOSE
Function for calculation of N N -> N N pi background (non-resonant), for the following channels:
INPUTS
- real, intent(in) :: srts --- sqrt(s)
- integer, intent(in), optional :: choice --- choice of parametrization: 1=Teis,2=Buss,3=Weil; if not given, the value is taken from the namelist switch 'NNpi_BG'
OUTPUT
- real :: sigma(4)
barBar_barBarMes/sig_NNV [ Functions ]
[ Top ] [ barBar_barBarMes ] [ Functions ]
NAME
real function sig_NNV(srts, charge_in)
PURPOSE
Calculates cross sections for:
- N N -> N N omega
- N N -> N N phi
- N N -> N N pi omega
in mb as function of sqrt(s), according to the parametrization (eq. 15) from Sibirtsev, Nucl. Phys. A 604 (1996) 455.
INPUTS
- real, intent(in) :: srts --- sqrt(s) in GeV
- integer, intent(in) :: charge_in --- total incoming charge (2=pp, 1=pn, 0=nn)
OUTPUT
- real :: sig(1:3) --- cross section in mb for the three channels
NOTE The parameters for channel (1) have been taken from Sibirtsev. The first parameter 'a' has been updated slightly by M. Abdel-Bary et al., Phys. Lett. B 647 (2007) 351. The parameters for channel (2) are from E.Ya. Paryev, J.Phys.G G36 (2009) 015103. The parameters for the third channel have been fitted to results of Pythia 6.4.25 (tuned).
barBar_barBarMes/chooseCharge_NNpiomega [ Functions ]
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NAME
subroutine chooseCharge_NNpiomega(chIn, chOut)
PURPOSE
Choose final state charges for N N -> N N pi omega, using Clebsch-Gordan factors which assume the pion is produced via a Delta.
INPUTS
- integer, dimension(1:2) :: chIn --- initial state charges (N,N)
OUTPUT
- integer, dimension(1:3) :: chOut --- final state charges (N,N,pi)