p-p and p-air interaction data in uv3.00 or later
There is some difference in the ad hoc model before and
after v3.0. In this page,
you can see some essential points of the changes in Version 3
including those of the new Lund code.
The new Lund code consists of 4 programs: Fritiof v7.02,
Jetset 7.3, Pythia 5.5, ariadone 4.02.
As in the figures in the previous page, x is defined simply by
the ratio of the energy of a secondary particle
to the incident proton energy in the laboratory system.
- Nucleon x-distribution at 100 GeV
xdN/dx is plotted for old Lund, ad-hoc and new Lund models.
- Nucleon x-distribution at higher
We see disappearing diffractive peak for the new Lund model
as energy goes higher.
- Multiplicity distribution by the new
Lund code with kfr(7)=2 for 10^18 eV pp collisions
We see strange double peaks so its not recommended to use
- Energy dependence of multiplicity
by ad hoc model and new Lund model. It is interesting to note that
the new Lund result for pp collisions is well fitted by the
QCD predicted energy dependence. (exp(sqrt(log(s))). There is
a small reduction of multiplicity in the ad hoc model (10 %)
as compared to the older versions. However, this effect in
observation might be seen only in low energy muons as a few
percent reduction of the number. The lines for the ad hoc
model are by approximate formulas shown in the fig. and must
be used at E > > 10 GeV.
- Comparison of pseudo rapidity
The ad hoc model results are compared with the UA5
minimum bias (inelastic) data.
- The same comparison as above by
new Lund code. At lower energies, the agreement with
the experimental data is not so bad, but at higher energies,...
If some one knows how to tune Fritiof v7.02, let me know.
- The epseudo rapidity for pp collisions
at 10^12, 10^15, 10^18, and 10^21 eV. The multiplicity reduction
from the fig. given in the previous page
is seen only in the central region
- The pseudo rapidity for p-air(
Nitrogen) collisionsWe see some skew (wider distribution
in the negative side) due to the nucleus effect.
- Transverse momentum distributions
of pions + kaons at various energies. This large Pt tail
is one of the improved points in V.3
- The X distribution of pions + kaons
This is unchanged from the older versions.
- log10(x) distribution of pions + kaons
for pp collisions. As in the case of the pseudo rapidity,
reduction of multiplicity from the older versions is
only in the central part.
- The same for p-air collisions