1. Bugs fixing in UrQMD 1.3 and 2.3
Improvements of UrQMD model for simulation of PbarP and PbarA interactions A. Galoyan, V. Uzhinsky
Bugs fixing in UrQMD 1.3 and 2.3
Stohastic interactions 1

2. 2

3. Bug fixing in UrQMD 1.3 File make22.f 3 Determination of the
c...get minimal masses
* call getirg(i1,i1m,i1p) ! Uzhi
call getirg(iabs(i1),i1m,i1p) ! Uzhi
m1m=mminit(i1m)
call getirg(i2,i2m,i2p) ! Uzhi
call getirg(iabs(i2),i2m,i2p) ! Uzhi
m2m=mminit(i2m)
Determination of the
range of possible baryon
resonances. It was wrong
For anti-baryons!
File make22.f 3

4. Bug fixing in UrQMD 1.3 It has a low influence on the produced mesons4

5. Bug fixing in UrQMD 2.3 There was the analogous mistake: File make22.f
c...get minimal masses
* call getirg(i1,i1m,i1p) ! Uzhi
call getirg(iabs(i1),i1m,i1p) ! Uzhi
m1m=mminit(i1m)
call getirg(i2,i2m,i2p) ! Uzhi
call getirg(iabs(i2),i2m,i2p) ! Uzhi
m2m=mminit(i2m)
Determination of the
range of possible baryon
resonances. It was wrong
For anti-baryons!
File make22.f
Plus a new bug!
c symmetrize or not angular distribution (depending on iline)
c this data statements may be changed ...
data symlog /14*.true., 1*.false., 6*.true., 7*.false.,
& *.true., 1*.false., 2*.true.,.false./ ! Uzhi
! & *.true., 1*.false., 2*.true./ ! Uzhi
File angdis.f
Angular distribution for a new PbarP reaction channel (39)
was not determined! 5

6. Difference between UrQMD 1.3 and UrQMD 2.3
A new process (XX-> 1/2 strings)
has been added in UrQMD 2.3 6

7. UrQMD 1.3 and UrQMD 2.3
There are some problems with baryon spectra. 7

8. UrQMD 1.3 and UrQMD 2.3
There are some problems with meson spectra. 8

9. UrQMD 1.3 and UrQMD 2.3 Meson spectra are too symmetric.
There are too many heavy
mesonic resonances in the
annihilation. 9

10. UrQMD 1.3 and UrQMD 2.3
Strange peak in proton spectra at Pt=0 (diffraction?). 10

11. Improved UrQMD 1.3 in PandaRoot for Pbar A interactions
Difference only 3 – 5 %. 11

12. Improved UrQMD 1.3 in PandaRoot for Pbar A interactions
Difference in high energy tail. 12

13. Improved UrQMD 1.3 in PandaRoot for Pbar A interactions
Difference is very small. 13

14. Improved UrQMD 1.3 in PandaRoot for Pbar A interactions
Difference is very small. 14

15. Implementation of ΞΞbar production
It is heavily to estimate and repeat calculations
by A. Kaidalov and P.Volkovitsky (Z. Phys. C 63, (1994) 15

16. Implementation of ΞΞbar production in every event of UrQMD+SMM model
Thus, for estimation of the
Nuclear re-scattering we assume
1. That Xi0 XiBar, Xi+, XiBar- are
produced in each annihilation act.
2. The following propagation of
the Xi is governed by UrQMD
nucleon potentials (Skyrm,
Yukawa, Pauli, Coulomb).
3. We are collecting and studying
the corresponding references.
There can be other potentials.
They can be accounted.
Algorithm
1. Changes in make22.f, urqmd.f,
angdisnew.f, output.f files
2. We consider all possible annihi-
lations of quarks. (Quarks of
projectile can be changed
during propagation before the
annihilations).
3. We did not include Xi’s in
nuclear residuals, though such
events of capture take place. 16

17. Implementation of ΞΞbar production
pbar + p at P_lab= 3GeV/c 17
Changes in angdisnew.f

18. Implementation of ΞΞbar production
pbar + C at P_lab= 3GeV/c
We did not considered clusterisation.
J. Pochodzalla, Phys. Lett. B 669 (2008) 306,
Exploring the potential of antihyperons in nuclei with antiprotons 18

19. Conclusion
A lot of experimental data on inclusive PbarP interactions has been collected.
2. Bugs are fixed in UrQMD 1.3 and 2.3. An influence of the bugs
on the results presented in Panda TPR is very small.
3. ΞΞbar production is implemented in UrQMD generator for
PANDA hyper-nuclear program. The same can be done for charmed meson and baryon production. 19