A comparative analysis of hadron and gamma families which have undergone the decascading procedure is made. Results are compared with different models of interactions. In hadron families with energies Summary E sub H sup gamma  20 TeV as well as in gamma families with energies Summary E sub gamma  70 TeV, increasing azimuthal anisotropy is observed

Azimov, S. A.

Halilov, D. A.

Mulladjanov, E. J.

Nosov, A. N.

Nuritdinov, H.

Talipov, D. A.

Yuldashbaev, T. S.

English

NASA Technical Reports Server

424
HE 3.7-1
A C01_IPARATIVE ANALYSIS OF Gfdv_vh%AND HADRON
FAMILIES AT THE SUPS/HIGHT ENERGIES RECORDED
IN EXPE_Iiv_ENT "PAMIR"
Azimov $.A. ,I_ulladjanov E.J.,Nosov A.N.,Nuritdinov H.
Talipov D.A.,Halilov D.A. ,Yuldashbaev T.S.
Physical-Technical Inatitute of Academy of
Sciences of the Uzbek SSR, USSR
In the paper a comparative analysis of hadron and
gamma families were undergone the decascading proce-
dure is made. Receive results are compared with dif-
ferent models of i_teractions. In hadron families
r, . J
with energies _E_ > 20 TeV as well as zn gamma fa-
milies with energies _Ey > 70 TeV increasing/ azi-
muthal anyzotr0py in events with large ER is observed.
INTRODUCTIO_
It's of interest compare different characteristics of
the gamma and hadron families at superhight energies. Howe-
ver, electromagnetic multiplication of the initial y-quanta
in the atmosphere has a great influence on observed charac-
teristics of the y-families decreasing sensitiveness these
characteristics (especially longitudinal) to different mo-
dels of strong interaction. Hadron families characteristics
are free the influence of those effects.
The de cascading procedure suggested in /I/ allow to re-
duce essentialy the influence of electromagnetic cascading
multiplication of the initial _-rays in the atmoaphere. All
particles paires satisfied the condition Zik _ Zo were com-
bined in single group (initial quantum), where Zik=Rik(I/Ei +
I/Ek)-I , Rik -the mutual distance of particle pair in mm,
El, E k -their energies in TeV. The decascading parameter was
set equal to Zo=IO TeV.mm. Thus the observed _o-families are
transformed in the initial _i-famil_. The comparison cha-
racteristics of the hadron-families (h-families) with such
_i-families is a more corred procedure than comporison with
observed families.
The experimental data about spatial characteristics of
the _i and h-families compare with simulated families calcu-
lated on different assumptions about mechanism of the str-
ong interaction. Different assum/otions about chemical comi)o-
sition of the primary cosmic radiation exert essential in -
flueace on the results of such analysis. Consequentl_ _, in
the pai_er an new selecbin_ criteria of _-faailies are for -
med b_ _rimary nuclei or i)rotons is 9ro_ose&.
,_e considered such spatial characteristics as R ( _ =
z'__RI / -distance of the from axis ofny_ R2 y-quanta faL_il_,
n_ --nu_0er 2articles of family0 and c< 10roposed in the
https://ntrs.nasa.gov/search.jsp?R=19850027647 2020-03-20T17:19:41+00:00Z
425
HE 3.7-1
,::_o_"k/2/ for analyse the structure of the families.
n
o( = _.Cosf_/(n(n-I)) , where Si J -the angle between
the mo_hgentumprojections of i-th and j-th particles in azi-
muthal XY-plane, perpendicular to the primary particles di-
rection, n -number of particles in family.
The value o_ reachs magnitude c_ = I for the complete-
ly complanar events and become minimal O_min = - I/(n-I)
in the case of an _ot_opic, uniform distribution of azimu-
thal angles.
I. The characteristics of the hadron and gamma
families
To analyse the spatial structure of y-families it is
impotant to have more complete information about particles
with large transverse momenta. Consequently it's were _in-
vestigated the experiment "Pamir" data obtained under con-
ditions when film scanning and particle selection were re-
alised within the radius R = 30 sm relatively the energy
weighted center of y-family. In the result were selected
N=326 y-families with energies _Ey=60.500 TeV and number
of particles n_ 4. The minimum ene_&_ of the Y-quants in
the families w_s set E¥=_ TeV. Particle scanning and selec-
tion h-families were r@alised within the radius R=30 sm too.
The m_nimum energy of the cascades in the h-families was
set E__ =4 _eV. It were selected N=I8I h-families with ener-
gies _ E_ =20.500 TeV.
At the analysis of the hadron families on record by "
"Pamir" carbon chamber, it is nesessary to take account the
formation structured events that is the groups of spots
with mutual distances less than -_I mm in X-ray film. The,
se narrow groups of spots corresponds to one hadron above
the chamber and originate from s_atial fluctuations in nuc-
lear-electromagnetic cascad (NEC)in the chamber /3/.
In the paper the groups of the electron-photon casca-
des (EPC) with mutual distanse less than 1.7 mm are consi-
dered as one cascade is produced by only hadron.
In table presents data about <R• and _ obtained
from experiment and from CS -scaling and CS_j -models /_I.
TABLE
: EXIFE_I_L_NT : C A L C U L A T I 0 N
: ' : : CS : CS_ j : CS_ j
:: Yi-fam. :: h-f am. :: Yi -fan" :: Yi-fan" i h-f am.
_ :_'6+-2oI _5.3+3 ._ :29.I+I.3 42.I+-3.8 _7.3_.8
_-- :O.i9+O.0i 0.26+0.02 :O.II+0.0I 0.2I+0.02 0.28+0.03
v
In CSCj-model the inelastic charge-exchange of leading char-
ge pion into neutral one J_±-_3F°+... and the jet produc-
tion processes was taken into account. The generation cross
426 HE 3.7-1
section of jets with large transverse momenta Ptj is calcu-
lated according to /5/. As one can see from table I only
jet generation model is in good agriment with experiment.
Fig.l presents data
, , , , , about the de._pendence of
-- • -- I the value o< on the soa-
O_ O- 2 tial parameter _ of _i
and hadi_on families ( I -0.z_ _- 3 _i-families, 2 -h-famili-
_ _ es 3 -h-famil es from
0,3 _ CS_j-model). Ai one can
see from figure I, the es-
0.2 sential incrisin_ of the
azimuthal correlation in
_X the of therange large0.I values R > 50 mm of the
hadron and _i-families
, i i a ' is observed. These resul-
I0 20 _0 80 R ,ram ts are in a good agriment
with the jet production
model while CS-model is
led to smaller values o[,
Fig. I R , than in experiment.
2. Gamma-families originated from nucleus-
nucleus (AA) and proton-nucleus (PA)
interactions
In the paper the selecting criteria of that families
obtained from the analysis of the y-families simulated on
the basis _iSF-model Z6/.
The criterion: i__ _0 mm and c_ < 0.2 for selection
of _vfamilies, originated from nucleus-nucleus interactions
(AA-families) is proposed, as for as AA-families are more
wide (the ma_orit$ _ of the fa_ililieshave the value _ >40 Lilil)
and isotfopic in the azimuthal plane than PA-fai_ilies. That
criterion select 65% AA- and 35% PA- of simulated famili-
es with energy _EE_=70-500 TeV, contained EPC with energies
E_ _ 2 TeV, lying within the radius R=30 sm from family
center.
• AA- a " ies at the observation level is 15_%.
This value is agree with assumption about normal chemical
composition of the primary cosmic radiation at energies
E o _ I0I5 eV.
Other proposed criterion: d = no/ ni where no and ni_
number of the observed and initial Y-quants in the families_
-" ) "According to _WSF-model, families with d >fl.6 or,glnatec
from protons (the admixture of AA-families compose -_9%),
and events with d _< 1.2 originated mainlo7 from nucleus-
427 HE 3.7-1
nucleus collisions (am-
_ I --_I ' ' ' ' '''" ong them 70% AA-and
30% PA-familie s).
0._ At the Fig.2 data
__ about the dependence
_--3 azimuthal co_relations
___ from value ER (E -energy
0.3 _ R-distance of the _-
0.2 quanta from axis of fam-
ily, I -experimental fa-
0.I - milies with d_I.6 ,
2 -experimental families
, , , ,, ,,,, with d _< 1.2 , 3 -CS_j-
I 200 500 IO00 _ model, _ -A_F-model for
events with d _ 1.2) is
TeV.mm presented.
How one can see
Fig. 2 from Fig.2, effect of
the azimuthal correla-
tions increasing in the range of the large values R and
connected with proton-nucleus interactions and descri-
bed by CS_j-model. On the other hand for the nucleus-nuc-
leus interactions the increasing azimuthal correlations is
not observed.
REFERENCEB
I. L.T.Baradzey, Yu.A.Smorodin, E.A.Solopov Preprint
FIAN N I03, I97_
2. S.A.Azimov, T.S.Yuldashbaev et.el. Zeszyty Naukove
Universitety Lodzkiego, Lodz 1977, z.60, Soil, p.28I
3. G.G.Leptuh et.el. Proc. of International Symposium on
Cosmic Rays and Particle Physics, Tokyo, _arch I9-23,
I984, p.26I
4. S.A.Azimov, E.J._ulladjanov, HoNuritdinov, D.A.Talipov,
. D.A.Halilov, T.S.Yuldashbaev Proc. I8-th ICRC, Banga-
lot, India I983, v°5, p._58
5. L.V.Gribov, E.f_.Levin, i_.G.Ryskin Phys.Lett. I2IB,
65, I983
" 6. R.A._ukhamedshin Proc. I7-th ICRC, Paris I98I, v.5,
p.3 3


A comparative analysis of gamma and hadron families at the superhigh energies recorded in experiment Pamir

A comparative analysis of gamma and hadron families at the superhigh energies recorded in experiment Pamir

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