INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES

HAL Id: jpa-00215230

https://hal.archives-ouvertes.fr/jpa-00215230

Submitted on 1 Jan 1973

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES

E. Pauli

To cite this version:

E. Pauli. INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES. Journal de Physique Col-

loques, 1973, 34 (C1), pp.C1-369-C1-372. �10.1051/jphyscol:1973150�. �jpa-00215230�

INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES

INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES

This topic can be divided into three main groups of experiments for this year.

1. MIRABELLE EXPERIMENTS. - The first group is represented by the hydrogen bubble chamber Mirabelle experiments for p + p at 69 GeV/c, K- + p at

32 GeV/c and a- + p at 50 GeV/c. Inclusive produc- tion of neutral and charged particles have been studied.

The main results are the following:

-

^{for p} + p + y + X

[ I ,

the number of a' per nega-

tive- particle is. decreasing with the number of negative particles. Furthermore, the invariant structure function f integrated over x shows signi-

2 2

ficant differences for pT > 0.10 (GeV/c) with the values of CERN-HAMBURG-VIENNA group at the I.S.R.

(Fig. 1). No possibility of factorization is observed between 0 < pT < 0.1 GeV/c and 0.1 < pT < 0.2 GeV/c.

1 W

z E 10

-

Ir-

1

0 010 O'M 030 0 010 020 030

Ff ( G.V/< ,2

FIG. 1.

-

Integrated structure function over a) p 2 and b) over x, compared to the results of the T CERN-HAMBURG-VIENNA group (solid line).

- f o r - ~ - ? - ~ - ~ ~ - ? - ~ - a n d - ~ ~ ? - ~ + A ⁺

x l21

9 the x or pT dependences of f at 69 GeV/c and 205 GeV/c at 2 NAL are compatible.

-

for p-+-p + T

-

+ X L3], a possible plateau in the y distribution is seen at 69 GeV/c with a width of

1.6 (Fig. 2).Limiting fragmentation is observed in the x distribution for 1x1 > 0.05 except for large pT, where one has to go to larger values of 1x1 to observe the same phenomenon (Fig. 3).

sig.2

- $ /(

((d2g)/(dy

9 ; ) )

dp; versus y for all topologies at 69 GeV/c compared to 28.5 GeV/c (dashed line), 102 GeV/c ( a ) , 205 Ge~/c ( 8 ) data.

The function is also given at 69 GeV/c for different topologies : 4-prong, 6-prong, 8-prong and 10-prong.

In the same experiment, the pT distribution is 2 decreasing faster for small 1x1 values than for all x (Fig.4).

- ---

for K-p -t KO*_ h

+

X at 32 GeV [41, the shape of has not changed appreciably when compared to data at 14 GeV.

For f P - ~ - ~ + - h [ 4 1 at the same en rgy distribution is parametrized as Ae-B' x-'rwh:re x _In 0.02 2 0.005, A

=

^6.8 mb/(~e~/c)~, B

=

^12.12

21.5 for x < x and B 5.75

f

0.5 for x > x

m m

(Fig.5).

- ---

^{for 'Irp 4 %- + X at 50 GeV/c [ 5 1 1} the x dis- tribution is compared to 8 GeV/c and 18.5 GeV/c [6].

It scales between 18.5 GeV/c and 50 GeV/c except for 0.3 ,C x 6 0 . 7

.

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1973150

FIG. 3.

-

~ ) l ( r & ~ $ ( d 2 u ) / ~ d x dp2) v e r s u s x f o r PT = 0 . 2 Ge f c , 0.4 e / c , 0.8 G ~ V & a t 69 GeV/c

(x,

*

⁾ compared t o Sims e t a l . (& = 7.4 GeV, f u l l l i n e ) , Cho e t a l . (& = 19.4 GeV,G\ W

A),

Dao e t a l .

(&

= 24.9 GeV,

V V

) , B e r t i n e t a 1 (& = 21

G ~ v , O ;

30 GeV, ; 44 GeV, 0 ; 52 GeV, A ) , Banner e t a l . (& = 23.2 GeV,

0

; 52.7 GeV, A ) .

2

f u l l l i n e ) , Cho e t a 1

(A

= 19.4 GeV, o)

,

Banner e t a l .

(A

⁼ 23.2 GeV, dashed l i n e ; = 23.2 GeV extrapolatec?, d o t t e d l i n e ) .

2 2

FIG. 5.

- - 'I

^(d o ) / ( d p , / dpT) dpT v e r s u s x i n K - ~ + y

+

X a t 32 GeV/c.

2 . COUNTER EXPERIMENTS.

- 7 - + p + p + X a n d f + p + p + X a t 2 5 a n d & _

--- --- --- ---- ---

G ~ V L ~ [ ~ ] .

-

^The x and t dependences of b o t h r e a c t i o n s

---

--

"-

have been compared (Fig. 6 ) , above t h e resonance r e g i o n .

K-p

- )5;

p CCERN-IHEP l972)

FIG. 6a).-(A a ) / ( ~ t 2 Ax) f o r K-p -+ p + X w i t h 0.18 <

It1 < 0.32 ( ~ e ~ / c ) ' a t 25 GeV/c (0) and 40 GeV/c

( 0 ) compared t o n-p + p + X a t 25 GeV/c (dashed l i n e ) . b) s l o p e b of t h e t dependence ~e~~ a t t h e c o r r e s p o n z d i n g e n e r g i e s and x v a l u e s .

INCLUSIVE DISTRIBUTIONS AT SERPUKHOV ENERGIES

-

-

-

^{n + p -t n} + X at 42 and 51 GeV/c

[ a ] . -

^The x de-

...

pendence of f for different pT for 0.9 2 < x < 0.99 is carefully studied and compared to a parametrization of a triple Regge pole nodel. Agreement is good for

x < 0.964 (Fig.7).

ISR

FIG. 8. - The values of the structure function at x = 0 integrated over p.$ and normalized to %ot

.

plotted as a function of s-t, for n+ + p -t nn, for n+

+

p + n- and 0 for n+ + p -t n*.

+ -

The s dependence of the n /IT ratio at x = 0 is also studied and compared to the p + p reactions. On

l 1 ' I observed that this ratio, for positive incident partit

.SO 90 .92 .94 .96 .98

-

cles, is decreasing to unity whereas for incident II

it is already constant at a momentum of 15

-

^{20 GeV/c.}

3 3

FIG. 7 .

-

E(d o]/(dp ) versus x for different inter- (Fig. 9).

vals of p, 2 in n- + D -t a-

+

X at 42.02 GeV/c solid

in the reactions r 4 0 GeVlc

1

-

^L

line: calcu~ations done with one pomeron pole.

- ^, t

---+-a

--- t ) ) ---

a p (n) + a* +

x

_[9

_I J

3. 2m PROPANE BUBBLE CHAMBER EXPERIMENT. - Three

papers are presented at this conference by the ^{3 -}

0

collaboration. They are based on inclusive produc- ^tQ ^- LZ

tion of r', y

,

A ( C ) and KO on protons and neutrons, _{I 2 -} x

Scaling for the first two reactions seems already FIG. 9.

-

The ratio of the number of n+ to the number of r- emitted at x

-

⁰ as a function of s-1;. A for present at x = 0 and results are compared to the _n+p, for r-p, for pp.

I.S.R. data between 500

-

1500 GeV (Fig. 8).

X + / Y'C- R A T I O AT 90'

a7 6 78 16 22 25 G-V/C ?if P REACTIONS

:

PP R E A C T I O ~ S L : :' r?w

A 12 24 500

'

11500

A

'

4 .

_mlr-P ^X+P

+

^{A PP}

In the third reaction, ';he Ki? pair production

-

grows with increasing energy of primary a meson.

The mean number of KO and 'A particles per

s-p i n t e r a c t i o n a r e (nkO) = 0.24

+

0.03 a n d ( n A o ) = 0.07

+

0.01, r e s p e c t i v e l y .

R e f e r e n c e s

[l] BLUMENFELD (H.) e t a l . , paper no. 232. [7] ANTIPOV (Yu.M.) e t a l . , paper no. 45, no. 46.

[2J BLUMENFELD (H.) e t a l . , p a p e r no. 231. [8] DEREVSHCHIKOV (A.A.) e t a l . , p a p e r no. 354.

PAUL1 (E.) e t a l . , p a p e r no. 228. [9] Paper no. 194.

[4] Paper no. 428. b0] BALEA ( 0 . ) e t a l . , p a p e r no. 198.

[5] P a p e r no. 427. D1-J BALEA (0.) e t a l . , p a p e r no. 406.

[6] BISWAS (N.N.) e t a l . , Univ. of Notre Dame, p r e p r i n t 71-44.