Digital computers used to calculate multiparticle interactions in high and superhigh energy regio

Artykov, I. Z.

Barashenkov, V. S.

Eliseyev, S. M.

English

NASA Technical Reports Server

., . 
w 
- 4  
National Aeronautics and Space Administration 
Goddard Space Flight Center 
Contract No.NAS-5-12487 
ST-PF-NP-I0662 
MULTIPARTICLE INTERACTIONS IN THE HIGH-AND SUPERHIGH- 
ENERGY REGION 
I.Z. Artykov 
V . S .  Barashenkov 
S .M. Eliseyev 
[USSR] 
6 8  
(NASA CR OR TMX O R  dD NUMBER)  
30 NOVEMBER 1967 
https://ntrs.nasa.gov/search.jsp?R=19680002600 2020-03-12T11:49:44+00:00Z
ST-PF-NP-I0662 
t 
MULTIPARTICLE INETERACTIONS I N  THE HIGH-AND SUPERHIGH- 
ENERGY REG1 ON 
J o i n t  I n s t i t u t e  of  Nuclear By I . Z .  Artykov 
Research a t  Dubna Laboratory V . S .  Barashenkov 
o f  T h e o r e t i c a l  Phys ics ,  I967  S . M .  E l i s eyev  
Up t o  t h e  p r e s e n t  t i m e ,  on ly  such types  of e lementary 
p a r t i c l e  i n t e r a c t i o n s  have been s t u d i e d  i n  accelerator 
experiments  and i n  cosmic r a y s ,  i n  which t h e  i n i t i a l  s t a t e  
c o n t a i n s  only one or t w o  p a r t i c l e s .  A t  t h e  same t i m e ,  
e l a s t i c  and i n e l a s t i c  p rocesses ,  desc r ibed  by Feynman's 
diagrams wi th  3 , 4  o r  a g r e a t e r  number of i n i t i a l  p a r t i c l e s ,  
are of  g r e a t  theoret ical  importance.  
I 
Unique p o s s i b i l i t i e s  f o r  s tudy ing  such type  of i n t e r a c t i o n s  I 
I 
are provided by experiments on i n e l a s t i c  c o l l i s i o n s  of 
p a r t i c l e s ,  genera ted  dur ing  a T-N o r  N-N i n t e r a c t i o n  i n s i d e  
t h e  nucleus as a r e s u l t  of t h e  Lorentz  compression e f f e c t ,  
escape  i n t o  a very narrow s o l i d  cone and t h e  n e x t  i n t r a n u c l e a r  
nucleon c a p t u r e s  ( o r  scatters) wi th  a h igh  p r o b a b i l i t y  several 
such p a r t i c l e s  a t  once [I,21 
high-energy p a r t i c l e s  w i th  atomic n u c l e i ,  when secondary 
Although p r e s e n t  exper imenta l  d a t a  on n u c l e a r  i n t e r a c t i o n s  
f o r  e n e r g i e s  T >  30 Gev are q u i t e  i n a c c u r a t e  and exper imenta l  
and theoret ical  d a t a  can be correlated f o r  each f i x e d  T- va lue  
w i t h i n  a broad range o f  assumptions concerning t h e  p r o p e r t i e s  
o f  m u l t i p a r t i c l e  i n e t e r a c t i o n s ,  an examination of  t h e  overall  
( aggrega te )  exper imenta l  d a t a  p r e s e n t l y  a v a i l a b e  m a k e s  it 
p o s s i b l e ,  however, t o  draw a number of s u f f i c i e n t l y  s p e c i f i c  
conclus ions .  
These conclus ions  are based upon t h e  comparison of 
exper imenta l  d a t a  wi th  a series of s tep-by-step (Monte-Carlo) 
c a l c u l a t i o n s ,  us ing  consecut ive ly  more p r e c i s e l y  de f ined  
assumptions on t h e  n a t u r e  of m u l t i p a r t i c l e  i n t e r a c t i o n s .  I n  
t h i s  connec t ion ,  t h e  s i m p l e s t  and m o s t  g e n e r a l  assumptions 
w e r e  used a t  f irst ,  such as t h e  independence of angu la r  and 
e n e r g e t i c  c h a r a c t e r i s t i c s  of produced p a r t i c l e s  on t h e  type  
of  such p a r t i c l e s ,  t h e  i s o t r o p y  of angu la r  d i s t r i b u t i o n s  i n  
d i g i t a l  computers, etc. ,  which w e r e  examined i n  d e t a i l  on ly  
as it became a b s o l u t e l y  necessary  t o  correlate t h e  r e s u l t s  of 
c a l c u l a t i o n s  w i t h  t h o s e  of t h e  experiment.  Such an approach 
p rov ides  s p e c i f i c  gua ran tees  a g a i n s t  t h e  inco rpora t ion  i n t o  
t h e  theory  of some u n s u b s t a n t i a t e d  and s p e c u l a t i v e  f a c t o r .  
- 2 -  
The c a l c u l a t i o n s  could be performed only by us ing  
high-speed computers; t h e  l a r g e  volume of i n p u t  in format ion  
r e q u i r e d  t h e  development of s p e c i a l  programs wi th  t h e  view 
of maximum economy of computer s t o r a g e  f a c i l i t i e s .  
The exper imenta l  d a t a  a v a i l a b l e  a t  t h e  p r e s e n t  t i m e  
do n o t  a l l o w  us t o  o b t a i n  as y e t  i s o l a t e d  ( s e p a r a t e )  i n f o r -  
mation on i n t e r a c t i o n s  wi th  p a r t i c l e  number m = 3,4 e tc .  
A t  p r e s e n t ,  conc lus ions  can be reached only on t h e  charac- 
teris  tics of m u l t i p a r t i c l e  i n t e r a c t i o n s ,  which a r e  averaged 
wi th  r e s p e c t  t o  t h e  number and type  of c o l l i d i n g  p a r t i c l e s .  
S ince ,  when T>> I Gev, numerous 'II -mesons are produced, t h i s  
means, b a s i c a l l y ,  t h a t  t h e s e  are i n t e r a c t i o n s  wi th  s e v e r a l  
mesons i n  t h e  i n i t i a l  s tate.  The p r o p e r t i e s  of such i n t e r -  
a c t i o n s  are q u i t e  s i m i l a r  t o  t h e  corresponding p r o p e r t i e s  of 
i n e l a s t i c  'II - N i n t e r a c t i o n s ,  namely, t h e r e  e x i s t s  a r e l e a s e d  
p a r t i c l e  c a r r y i n g  away about 50% of t h e  t o t a l  energy,  t h e  
angu la r  d i s t r i b u t i o n s  are s h a r p l y  asymmetric w i th  a charac- 
t e r i s t ic  dependence of t h e  asymmetry on t h e  type  of p a r t i c l e  
gene ra t ed  t h e  mean energy and t h e  mean m u l t i p l i c i t y  o f  t h e s e  
p a r t i c l e s  i n c r e a s e s  approximately as T1/,+, and an average  of 
IO-20% heavy p a r t i c l e s  are genera ted  a t  very  h igh  e n e r g i e s .  
F igures  I and 2 show unstandardized e n e r g e t i c  and 
angu la r  d i s t r i b u t i o n s  of p a r t i c l e s  from i n e l a s t i c  mul t i -  
p a r t i c l e  i n t e r a c t i o n s  f o r  several energy va lues .  Of course ,  
no s e r i o u s  s i g n i f i c a n c e  can be a t t r i b u t e d  t o  d e t a i l s  of 
t h e s e  d i s t r i b u t i o n s ,  s i n c e  wi th in  t h e  l i m i t s  of exper imenta l  
errors agreement wi th  t es t  d a t a  can be ob ta ined  bo th  i n  t h e  
case of somewhat smoother and somewhat s t e e p e r  curves .  However, 
t h e  main f e a t u r e s  of t h e  d i s t r i b u t i o n s  remain i n v a r i a b l e .  
To a r r i v e  a t  more d e t a i l e d  conclus ions ,  p recess ion  
measurements are of  great importance,  which can be c a r r i e d  
a t  60-70 Gev wi th  t h e  Serpukhov accelerator. 
I t  should be noted  t h a t  t h e  c o n t r i b u t i o n  of m u l t i p a r t i c l e  
i n t e r a c t i o n s  i s  found t o  be g r e a t e r  i n  t h e  case of l i g h t  n u c l e i .  
For example, a t  T = I O O  Gev, t h e  r a t i o  of m u l t i p a r t i c l e  i n t e r -  
a c t i o n s  i n s i d e  l i g h t ,  medium and heavy n u c l e i  of a photo- 
emulsion i s  r e s p e c t i v e l y  t o  38, 30 and 28%. 
REFERENCES 
I. I . Z .  Artykov, V.S. Barashenkov and S . M .  E l i s eyev ,  Izv .  
AN S S S R ,  ser. f i z .  ( i n  p r i n t ) ,  p r e p r i n t  O I Y A I  R2-3005 
1 9 6 6 .  
2.  S . M .  E l i s eyev ,  Cadida te ' s  d i s s e r t a t i o n ,  J o i n t  I n s t i t u t e  
of  Nuclear Research, I 9 6 7  
Manuscript r ece ived  by E d i t o r i a l  
Board on I 3  September 1967.  
- 3 -  
0.2 
0.1 
0 
f 2 3  1. E,+ r38 - G e v  
2. ~ , - - 2 o r ~ ~  
3. E,>~o r38 
I I I 
, -----__ 
0.5 
II 
II 
1.5 2 
Fig.  I. Energy d i s t r i b u t i o n  i n  a d i g i t a l  computer of 
p a r t i c l e s  genera ted  dur ing  an i n e l a s t i c  m u l t i p a r t i c l e  
i n t e r a c t i o n .  Ec is  t h e  t o a t l  ( o v e r a l l )  energy of t h e  
m u l t i p a r t i c l e  system which can be used f o r  t h e  
formation o f  new p a r t i c l e s .  
S o l i d - l i n e  curves correspond t o  nucleons,  broken-l ine 
curves t o  II -mesons. 
- 4 -  
w (cost31 
1 1 I 
0.2 
0.1 
0 
-1 
Fig .  2 .  Angu la r  d i s t r i b u t i o n s  i n  a d i g i t a l  computer of par t ic les  
g e n e r a t e d  d u r i n g  an i n e l a s t i c  m u l t i p a r t i c l e  i n t e r a c t i o n s .  
Symbols are the s a m e  as t h o s e  i n  F i g .  I. 
CONTRACT No.NAS-5-12487 
VOLT TECHNICAL CORPORATION 
Washington D.C. 
T e l :  223-6700 
T r a n s l a t e d  by:  
A. S c h i d l o v s k y  
Revised by:  
D r .  Andre L. B r i c h a n t  
. 
on November 30 I967  


Multiparticle interactions in the high and superhigh energy region

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server