WEAK INTERACTIONS SUMMARY OF THE PARALLEL SESSIONS

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WEAK INTERACTIONS SUMMARY OF THE PARALLEL SESSIONS

V. Soergel

To cite this version:

V. Soergel. WEAK INTERACTIONS SUMMARY OF THE PARALLEL SESSIONS. Journal de

Physique Colloques, 1973, 34 (C1), pp.C1-83-C1-90. �10.1051/jphyscol:1973105�. �jpa-00215185�

WEAK INTERACTIONS

SUMMARY OF TBE PARALLEL SESSIONS

V. SOERCEL

U n i v e r s i t y of H e i d e l b e r g

T h e r e s u l t s of t h e f o l l o w i n g p a p e r s were p r e s e n t e d d u r i n g t h e p a r a l l e l s e s s i o n s .

Hyperon B e t a Decays

- -

" \ g A / g V \ i n t h e decay 2- -+ n e v

",

V. Hunger- b u e h l e r e t a l . (NAL,BNL), n0365, p r e s e n t e d by J. Marx.

CP V i o l a t i o n

"A measurement o f t h e l e p t o n c h a r g e asymmetry i n

+ -

K: -) x - 8 ' ~ d e c a y s v ' , H . H . W i l l i a m s e t a l . (BNL, Y a l e ) , n0294, p r e s e n t e d by H.H. Williams.

h he

CP v i o l a t i n g a m p l i t u d e i n t h e decay K O -+ x+x-

",

C. Gel-eniger e t a l . (CERN, H e i d e l b e r g ) , n0419, p r e - s e n t e d by H. Wahl.

"hleasurements of t h e c h a r g e asymmetry i n t h e d e c a y s

+ - + -

K O -+ <e+v and K O -+ ~ - ~ + v

",

C. Geweniger e t a l . (CERN, H e i d e l b e r g ) , n0420, p r e s e n t e d by P. S t e f f e n .

"Measurement of t h e phase @

+ -

of t h e C P - v i o l a t i o n p a r a m e t e r T I -

",

D.R. Nygren e t a l . (Columbia, NYU), a b s t r a c t n0216, no p a p e r s u b m i t t e d , p r e s e n t e d by D.R.

Nygren.

Keg Form F a c t o r s

"Measurement of t h e form f a c t o r s i n t h e decay

<

^{+ XgV}

^",

^{G .} Donaldson e t a l . (SLAC, S a n t a C r u z ) ; n0152, p u b l i s h e d i n Phys. Rev. L e t t .

31

( 1 9 7 3 ) 337 ; and n0259, p r e s e n t e d by D. H i t l i n .

"A measurement o f t h e b r a n c h i n g r a t i o

I'(<

+ ;>u) / i'(< + 2 e ; v ) ^{' I ,} H.11. W i l l i a m s e t a l . (BNL, Y a l e ) , n0295.

" ~ x p e r i m e n t a l s t u d y of t h e form f a c t o r s i n t h e de- c a y K + ^-+ $e+v

",

^{H .} Braun e t a l . ( A a c h q , B a r i , B r u s - s e l s , CERN)

,

n0300.

" ~ n e x p e r i m e n t a l d e t e r m i n a t i o n of t h e form f a c t o r s i n t h e decay K+ -t xOp+v

",

H. Braun e t a l . (Aachen, B a r i

,

B r u s s e l s , CERN ) n0301.

"<

decay form f a c t o r s " , R. Z d a n i s e t a l . (John Hopkins, UCLA, SLAC), n0318, r e f e r r e d t o a s JUS 1 1 , p r e s e n t e d by D. Drickey.

" ~ e a s u r e m e n t of t h e q2 dependence of t h e form f a c - t o r i n t h e decay K O 4 x e v

",

S. G j e s d a l e t a l . (CERN,

H e i d e l b e r g ) n0421, p r e s e n t e d by F. E i s e l e .

"A s t u d y of t h e form f a c t o r s i n t h e K O d e c a y s q ' , 113

K.F. A l b r e c h t e t a l . (Dubna, B u d a p e s t , B e r l i n , P r a - gue, Serpukhov, S o f i a ) , n0437.

O t h e r T o p i c s

" ~ e w measurements o f t h e A l i f e t i m e " , G. P o u l a r d e t a l . ( S a c l a y ) , n058.

"A new d e t e r m i n a t i o n of t h e 11' mean l i f e s ' , K.H.

A l t h o f f e t a l . (CERN, H e i d e l b e r g ) , n0158.

" ~ e a s u r e m e n t s o f t h e b r a n c h i n g r a t i o and x0 e n e r a spectrum f o r K O -+ x'x-xo

",

C. Alexander e t a l .

L

(Tel-Aviv, H e i d e l b e r g ) , n076.

" s e a r c h f o r & = 2 d e c a y s of n e u t r a l E h y p e r o n s T ' , C. Ceweniger e t a l . (CERN, H e i d e l b e r g ) , A b s t r a c t n0233, no p a p e r s u b m i t t e d .

" F u r t h e r o b s e r v a t i o n of t h e decay

<

^->

^{; ) ; ",}

W.C. C a r i t h e r s e t a l . (Columbia, BNL, CERN), n0177, p r e s e n t e d by K.W. L a i .

"A measurement of K+ decay1', K . S . Heard e t a l . e w

(CERN. H e i d e l b e r g ) , n0277, p r e s e n t e d by H.\V. S i e b e r t .

SUMMARY OF THE PARALLEL SESSION

1 . - l i f e t i m e

Two p a p e r s s u b m i t t e d r e p o r t on new measurements of t h e A0 l i f e t i m e :

P a p e r Number of Method R e s u l t

e v e n t s

n0158 o p t i c ; l

CERN, 6 6 0 0 s p a r k ( 2 . 6 9 + . 0 5 ) ~ 1 0 - ~ ~ s

H e i d e l b e r g chonber

-

B o t h v a l u e s a r e s i g n i f i c c n t l y h i g h e r t h a n t h e p r e - v i o u s world a v e r a z e : zA(r.a)

=

( 2 . 5 2 1 * . 0 2 1 ) ~ 1 0 - ~ ~ s . 'Their w e i g h t e d s e a n i s

z (Aix 1973) ^I ( 2 . 6 3 ~ . 0 2 ) ~ 1 0 - ~ ~ s

=

( 1 . 0 4 5 + - . 0 1 2 ) x ~ ~ ( w . o ) A

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1973105

C1-04 V. SOERGEL

2.

-

& 12 t r a n s i t i o n s

The CERN-Heidelberg group (Geweniger e t a l . , a b s - t r a c t n0233) h a v e s e a r c h e d f o r t h e d e c a y

? *

p7c-

.

An u p p e r l i m i t : r(kO + X-)

< 3 . 5 ~ 1 0 - ~ (9% c . L . )

T(IO+ A

2 )

i s o b t a i n e d , which i s by a f a c t o r 6 0 l o w e r t h a n t h e p r e v i o u s u p p e r l i m i t , c o n f i r m i n g t o t h i s l e v e l t h e a b s e n c e of non l e p t o n i c & ¹ 2 t r a n s i t i o n .

+ - 0 3 . -

< -

^{il7t 7c} d e c a y

A new v a l u e of t h e b r a n c h i n g r a t i o ,

-

^7t+717c0) 0 . 1 6 0 5 2 .0038

+ c h a r g e d )

was s u b m i t t e d by t h e T e l - A v i v , H e i d e l b e r g c o l l a b o r a - t i o n ( p a p e r n 0 7 6 ) , which i s i n e x c e l l e n t a g r e e m e n t w i t h t h e p r e v i o u s w o r l d a v e r a g e R(w.a) =.1612*.0038.

R e s u l t s on t h e l i n e a r s l o p e p a r a m e t e r g of t h e

2-

s p e c t r u m were g i v e n i n two p a p e r s :

which b o t h a g r e e w i t h t h e p r e v i o u s w o r l d a v e r a g e : g ( w . a )

=

0 . 6 0 3 i . 0 2 8

.

4 .

-

C - -t ne-v d e c a y

The Yale, NAL, BNL g r o u p r e p o r t e d on t h e f i r s t r e s u l t s on h y p e r o n b e t s d e c a y o b t a i n e d w i t h a n hype- r o n beam. The r a t i o Ig / g

\

i n t h e d e c a y 2 + nev was

A V

o b t a i n e d from t h e n e u t r o n s p e c t r u m of ~ 3 0 0 0 r e c o n s - t r u c t e d e v e n t s ( p a p e r n0365). The s e t up i s shown i n f i g u r e 1, T h e momenta of t h e C - and of t h e c h a r g e d d e c a y p a r t i c l e ..vere measured by m a g n e t i c s p e c t r c m e - t e r s w i t h m a g n e t o s t r i c t i v e w i r e chambers. The el-ec- t r o n was i d e n t i f i e d by a t h r e s h o l d Cerenkov c o u n t e r . A t o t a l a b s o r p t i o n c a l o r i m e t e r i d e n t i f i e d a f a s t

f o r w a r d h a d r o n whose i n t e r a c t i o n p o i n t was d e t e r m i - ned by a m u l t i p l e l a y e r sandwich of i r o n c o n v e r t o r s , w i r e p r o p o r t i o n a l chambers a n d s c i n t i l l a t o r s . The d i r e c t i o n of t h e n e u t r o n is t h e n d e t e r m i n e d t o b e t - t e r t h a n 1 mrad

.

The c r u d e i n f o r m a t i o n on t h e neu- t r o n e n e r g y (220%) was n o t u s e d i n t h e a n a l y s i s . T h u s , t h e e v e n t r e c o n s t r u c t i o n h a s z e r o c o n s t r a i n t s T e l - A v i v , H e i d e l b e r g , p a p e r n076 g = 0 . 6 1 9 + . 0 3 2

a n d a t w o f o l d a m b i g u i t y . E v e n t s which u n d e r t h e hy- JUS I 1 p a p e r n0318 g - 0 . 5 9 0 * . 0 2 1

p o t h e s i s of 2 - + nx- d e c a y g i v e a r e c o n s t r u c t e d 2 -

HlGH ENERGY NEGATIVE HYPEROM. BEAM

HlGH RESOLUTION

SPARK CHAMBER

7

^SCALE

^--

^{0 LFEET}

TARGET

W m

UNGSTEN EAM DUMP

COUNTER(

E ,

^{)PION VETO}

ENLARGED VIEW AT O dINCHES

ENLARGED

VIEW

AT'B'

0-

4 INCHES

' E R

F i g . 1 . - S c h e m a t i c d i a g r a m of t h e h i & e n e r g y h y p e r o n beam a t t h e BNL AGS.

WEAK INTERACTIONS

-

PARALLEL SESSIONS

m a s s o f more t h a n 1 1 6 5 MeV a r e e l i m i n a t e d i n o r d e r t o s u p p r e s s b a c k g r o u n d f r o m two-body d e c a y . T h e r a t i o lgA/gVI i s o b t a i n e d f r o m a maximum l i k e l i h o o d f i t t o t h e n e u t r o n s p e c t r u m . B o t h s o l u t i o n s w e r e u s e d w i t h a w e i g h t g i v e n by Monte C a r l o . T h e r e s u l t i s

F i g . 2 . - S p e c t r a o f K c a n d i d a t e s

( a ) 1 3 1 e c t r o n e W s p e c t r u m , l o g a r i t h m i c s c a l e . Smooth c u r v e : c a l c u l a t e d K - s p e c t r u m .

e 3

( b ) L i n e a r scale, s m o o t h c u r v e s : c a l c u l a t e d s p e c t r a f 0 c . f t e r m ( s o l i d l i n e ) , a n d f - t e r m ( d a - s h e d l i n e ) . ⁺

( c ) y e n e r g y s p e c t r u m o f K c a n d i d a t e s a- b o v e 2 3 6 MeV/c. Smooth c u r v e s : c a p x l a t e d s p e c t r a f o r f + t e r m ( s o l i d l i n e ) a n d f - t e r m ( d a s h e d l i n e ) .

i n g o o d a g r e e m e n t w i t h e x p e c t a t i o n s f r o m r e c e n t C a b i b b o f i ts.

T h e r e is some h o p e t o g e t i n a f d h e r a n a l y s i s a l s o t h e s i g n o f

g A / g V f r o m t h c s h a p e o f t h e e l e c - t r o n s p e c t r u m .

5.- K + + e+vY d e c a y

T h e C E R N - H e i d e l b e r g g r o u p ( H e a r d e t a l . p a p e r n 0 2 7 7 ) r e p o r t e d o n t h e f i r s t o b s e r v a t i o n o f t h e s t r u c t u r e d e p e n d e n t d e c a y K + + e + v y

.

^{A 56*} e v e n t s w i t h Ee > 2 3 6 MeV

,

^Ey

9

1 0 0 M e V and 0 > 140'

ey

h a v e b e e n o b t a i n e d . I n t e r n a l B r e m s t r a h l u n g a n d Ex- t e r n a l B r e m s t r a h l u n g i n t h e t a r g e t f r o m K + + e f v d e c a y c o n t r i b u t e s < 1 e v e n t . T h e d a t a w e r e t a k e n c o n c u r r e n t l y w i t h d a t a o n K + + e + ~ d e c a y w h i c h w c r e u s e d f o r n o r m a l i z a t i o n . T a k i n g i n t o a c c o u n t t h e de- t e c t i o n e f f i c i e n c y f o r t h e y - r a y s ( 0 . 7 2 S . 1 2 ) a n d t h e f r a c t i o n of e v e n t s c o n t a i n e d i n t h e a c c e p t e d re- g i o n o f t h e D a l i t z p l o t a s w e l l a s c o r r c c t i o n f o r e x t e r n a l B r e m s t r a h l u n g a n d s p e c t r o m e t e r r e s o l u t i o n , t h e b r a n c h i n g r a t i o t u r n s o u t t o b e

I n t h i s a n a l y s i s i t was assumed t h a t d u e t o t h e e n e r g y a n d a n g l e c u t s o n l y r i g h t h a n d e d p h o t o n s c o n - t r i b u t e t o t h e o b s e r v e d r a t e . T h i s 1s I n good a g r e c - ment w i t h t h e e l e c t r o n a n d y - r a y s p e c t r a o b t a i n e d , ( F i g . 2 ) , w h i c h y i e l d < 7 - e v e n t s w i t h l e f t h a n d e d

p h o t o n s .

6 . - Ke3 f o r m f a c t o r s

T h i s s u b j e c t

,

w h e r e v c r y s i g n i f i c a n t a n d i m p o r t a n t e x p e r i m e n t a l r e s u l t s w e r e c o n t r i b u t e d t o t h e C o n f e - r e n c e by s e v e r a l g r o u p s w i l l b e c o v e r e d i n t h e r e p o r t by P r o f e s s o r S t e c h . O n l y some c o m p l e m e n t a r y i n f o r -

! l a t i o n w i l l b e g i v e n h e r e . 6.1.

-

:K d e c a y

T h e r e w e r e f o u r p a p e r s s u b m i t t e d , g i v i n g e x p e r i - m e n t a l r e s u l t s o n t h e f o r m f a c t o r s :

CERN

-

H e i d e l b e r g ( G j e s d a l e t a l . , p a p e r n0421 ).

T h e D a l i t z - p l o t d i s t r i b u t i o n of 500 0 0 0

~z~

d e c a y s h a s b e e n s t u d i e d t o m e a s u r e t h e q2 d e p e n d e n c e o f t h e v e c t o r f o r m f a c t o r f +

.

T h e d e c a y s w e r e r e c o r d e d i n a m a g n e t i c s p e c t r o m e t e r e m p l o y i n g m u l t i w i r e p r o p o r - t i o n a l c h a m b e r s .

C l e a n K d e c a y s w e r c i d e n t i f i e d by k i n e m a t i c s a n d e 3

a h y d r o g e n g a s C e r c n k o v c o u n t e r . T h e a c c e p t a n c e c o - v e r s t h e w h o l e D a l i t z p l o t n e a r l y i n d e p e n d e n t of q 2

.

T b e o b s e r v e d f o r m f a c t o r rises l i n e a r l y w i t h q2/m2

V. SOERGEL

SWEEPING MAGNET

MU^ WIRE ~ R T I O N A L cmwm RIGGERCOUNTERS W C W N T E I

v

TARGET COLLIMATOR B

\

SWEEPING MAGNET

P R ~ T O N BEAM AMIC' CUNTER

MUT~ WIRE ~ R T I O N A L CHAMBEE RIGGERCOUNTERS W C W N T E I

F i g . 3 . - S e t up of t h e K O s p e c t r o m e t e r i n t h e w i t h a s l o p e h

=

( 0 . 0 3 1 = 0 . 0 0 2 5 ) i n good a g r e e m e n t w i t h ~ ~ ( 8 9 0 ) dor,linance models. I n t h e a n a l y s i s , a pu- r e v e c t o r - i n t e r a c t i o n i s assumed. When a n a l y s e d i n t e r m s of a n a d m i x t u r e of s c a l a r o r t e n s o r c o u p l i n g s , i t i s found t h a t t h e r e l a t i v e c o n t r i b u t i o n t o t h e decay r a t e i s < 2 x 1 0 - ~ f o r s c a l a r and f o r t e n s o r . ( F i g s . 1 and 2 i n S t e c h ' s r e p o r t )

J o h n Hopkins-UCLA -SLAC ( Z d a n i s e t a l . , p a p e r n"318).

I n t h i s e x p e r i m e n t b o t h K and K d d e c a y s a r e s t u - e 3

d i e d . The d a t a were t a k e n a t SLAC u s i n g a n a p p a r a t u s d e s c r i b e d e a r l i e r ( P h y s . L e t t .

33

( 1 9 7 0 ) 623 ), w i t h some minor c h a n g e s . The Keg d a t a g i v e a l i n e a r l y r i - s i n g form f a c t o r f ( q 2 ) w i t h

X =

0.044iO.006 ; u s i n g t h i s v a l u e a s a n i n p u t , t h e K d a t a y i e l d a

2

P

l i n e a r l y r i s i n g f o ( q ) w i t h 1 = 0 . 0 3 2 * 0 . 0 1 0

.

^No

a t t e m p t was made t o e x t r a c t b o t h form f a c t o r s from t h e K - d a t a a l o n e .

P

SLAC-Santa C r u z (Donaldson e t a l . , papers n0152 a n d n C 2 5 9 ) .

T h i s i s a v e r y h i g h s t a t i s t i c s ( 1 . 6 ~ 1 0 ' e v e n t s ) e x - p e r i m e n t on t h e D a l i t z p l o t d i s t r i b u t i o n of K O + T+V

L d s c a y . T h e method and t h e r e s u l t s a r e d e s c r i b e d i n P h y s . Rev. L e t t . 2 . ( 1 9 7 3 ) 3 3 7 , t h e r e f o r e o n l y t h e f i n a l r e s u l t s a r e q u o t e d h e r e . The d a t a g i v e good f i t s t o form f a c t o r s w i t h l i n e a r q 2 -dependence, when a p p a r a t u s d e p e n d e n t r a d i a t i v e c o r r e c t i o n s a r e made.

From two-parameter f i t s t o t h c D a l i t z p l o t w i t h f ( 0 ) E f ( 0 ) a 1

,

t h e v a l u e s A

=

0 . 0 3 0 i 0 . 0 0 3

,

h ^I 0.019i0.004 and f

=

-0.11f_0.02 a r e o b t a i n e d . The r e s u l t s of u n p a r a m e t r i z e d f i t s a r e shown i n Fig.3 of S ' c e c h ' s r e p o r t .

s h o r t n e u t r a l beam a t t h e CERN

-

PS.

I f t h e f i t a l l o w s f o r 2 c o n s t a n t t e n s o r form f a c - t o r f T a n d assumes f and f o t o b e l i n e a r i n q 2

,

\ f T l / f + ( 0 ) < 0.016 (9546 c o n f i d e n c e l e v e l ) i s o b t a i - ned. The e x t e n s i v e p a p e r o n t h i s e x p e r i m e n t s u b m i t - t e d t o t h e C o n f e r e n c e ( p a p e r n0259) which i n c l u d e s a r e v i e w o n p r e v i o u s work on Ke3-decay, w i l l soon b e p u b l i s h e d i n P h y s . Rev.

Dubna - B u d a p e s t - B e r l i n

-

P r a g u e

-

Serpukhov

-

S o f i a

-

C o l l a b o r a t i o n ( A l b r e c h t e t a l . , p a p e r n 0 4 3 7 ) . A D a l i t z p l o t a n a f y s i s of 8 2 400 s e l e c t e d K de- c a y s was c a r r i e d o u t , which were o b s e r v e d i n t h e

P

Serpukhov n e u t r a l beam by means of a w i r e ~ h a m b e r l n a g n e t i c s p e c t r o m e t e r . The l i n e a r b e h a v i o u r of t h e f o r m - f a c t o r s i s d e m o n s t r a t e d . Two p o s s i b l e so1utiol:s a r e o b t a i n e d b o t h f o r t h e s c a l a r and t h e v e c t o r

f o r m - f a c t o r s . T h e s e s o l u t i o n s can be a s s o c i a t e d w i t h t h e two m u t u a l l y i n c o n s i s t e n t r e s u l t s o b t a i n e d e a r - l i e r from s i m i l a r e x p e r i m e n t s . One of t h e two s o l u - t i o n s which i s c l o s e r t o t h e c u r r e n t Keg d a t a g i v e s f o r t h e s l o p e s of t h e v e c t o r and s c a l a r f o r m - f a c t o r s :

6.2.-

K13

d e c a y

Two p a p e r s s u b m i t t e d by t h e A a c h e n - B a r i - B r u s s e l s - CERN C o l l a b o r a t i o n ( n 0 3 0 0 and n0301) r e p o r t on r e s - p e c t i v e l y 2827 K + -r $ev and 1897 K+ -t nos" de- c a y s o b s e r v c d i n t h e 1 . 1 m 3 heavy l i q u i d b u b b l e chamber a t CERN. The d a t a on Keg d e c a y a r e c o n s i s - t e n t w i t h a l i n e a r l y r i s i n g f + ( q 2 ) w i t h

h

=

0 . 0 2 7 t 0 . 0 8

,

t h e K d a t a y i e l d X =0.025+-3.017

+

₂

P

and E(G.6 m ) z 4 . 3 4 i . 2 0 i n agreement w i t h t h e

WEAK INTERACTIONS

-

PARALLEL SESSIONS C1-87

f i n d i n g s on t h e K; d e c a y s . u n p a r a m e t r i z e d a n a l y s i s o n l y t o z r a p h i c a l l y demons-

- -

I n t h e r e p o r t of P r o f e s s o r S t e c h , t h e new d a t a on Keg form f a c t o r s a r e d i s p l a y e d i n t a b l e , i n c l u d i n g a new r e s u l t on t h e T(< +

G(IFv)/

^{T(K; + $eFv)}

b r a n c h i n g r a t i o ( p a p e r n0295)

+ -

T(KO -+ X - ~ + U )

L

- =

. 6 7 2 t . O 3 5

.

T(K; -+ nte+v)

I n t h e f o l l o w i n g , a n o t e of D. H i t l i n c o n c e r n i n g t h e p r o c e d u r e i n e x t r a c t i n g f o r m f a c t o r s from K

P

d a t a w i t h s p e c i a l r e f e r e n c e t o t h e S L 4 C - S a n t a CruZ r e s u l t s and on r a d i a t i v e c o r r e c t i o n s i n K decay

e 3 e x p e r i m e n t s i s reproduced.

6.3.- E x t r a c t i o n of t h e t - d e p e n d e n c e of t h e f o r m f a c t o r s (D. H i t l i n ) .

-

Most r e c e n t K D a l i t z p l o t a n a l y s e s have e x t r a c t e d

P

t h e t - d e p e n d e n c e of t h e f o r m f a c t o r s by making Itunpa- r a m e t r i z e d " f i t s t o t h e i r d a t a . When t h i s p r o c e d u r e i s f o l l o w e d , t h e v a l u e s of f and f o ( o r f + and f ) o b t a i n e d a t a g i v e n t a r e h i g h l y c o r r e l a t e d . The de- g r e e of c o r r e l a t i o n ( d f o / d f + o r d f / d f + ) v a r i e s a c r o s s t h e D a l i t z p l o t , and e s p e c i a l l y a t low t , t h e a s s o c i a - t e d e r r o r s may b e n o n - G a u s s i a n and a s y m m e t r i c ( s e e F i g . 4 ) .

INNER ELLIPSE I u ,,,,.,,

OUTER ELLIPSE 2 0

F i g . 4 .

-

E r r o r e l l i p s e s of f v s .

5

^{and f} v s . f o f o r t h r e e d i f f e r e n t v a l u e s &f t r q2

.

T h i s p r e s e n t s a problem i n a s c e r t a i n i n g t h e t depen- d e n c e of t h e form f a c t o r s i n t h e t w o - s t e p p r o c e s s which must be u s e d , s i n c e t h e a p o s t e r i o r i f i t t o t h e l i n e a r form f a c t o r h y p o t h e s i s assumes t h a t t h e e r r o r s on p o i n t s a t e a c h t a r e G a u s s i a n , a n d c o r r e l a t i o n s between t h e form f a c t o r s a r e n o t t a k e n i n t o a c c o u n t . I t i s c l e a r t h a t t h e v a l u e s of A+ and ho e x t r a c t e d i n t h i s way must be c o r r e l a t e d , b u t t h e c o n v e n t i o n a l

" u n p a r a m e t r i z e d t ' p r o c e d u r e d e s c r i b e d a b o v e i g n o r e s t h i s i m p o r t a n t f a c t

I n o r d e r t o p r o p e r l y t a k e t h e c o r r e l a t i o n s i n t o a c - a u n t t h e SLAC- S a n t a C r u z e x p e r i m e n t h a s u s e d t h e

t r a t e t h e a b s e n c e of l a r g e d e v i a t i o n s from l i n e a r i t y and e m p h a s i z e t h a t we f i n d t h a t f o i n c r e a s e s w i t h t.

We h a v e u s e d a two-parameter f i t t o t h e e n t i r e Da- l i t z p l o t t o e x t r a c t t h e t - d e p e n d e n c e of f and f o , s i n c e t h i s f i t m a n i f e s t l y i n c l u d e s ' c o r r c l a t i o n s and a l l o w s u s t o s e e and u n d e r s t a n d t h e m a g n i t u d e of t h e s e c o r r e l a t i o n s ( s e e F i g . 5 ) .

F i g . 5 . - E r r o r e l l i p s e s f o r t h e two-parameter f i t s . The s a t i s f a c t o r y ,y2 f o r t h e two-parameter f i t ( 3 9 6 f o r 3 9 8 d e g r e e s of f r e e d o m ) allso i n d i c a t e s t o u s t h a t t h e f a c t t h a t f o ( 0 ) / f + ( O ) f a i l s t o r e a c h 1 . 0 by s o m e t h i n g o v e r one s t a n d a r d d e v i a t i o n i n t h e u n p a r a m e t r i z e d f i t i s p r o b a b l y l a r g e l y d u e t o c o r r e - l a t i o n s a n d non-Ciaussian e r r o r s , and i s n o t a s e r i o u s problem.

6 . 4 . R a d i a t i v e c o r r e c t i o n s . -

A s we h a v e now a p p a r e n t l y r e a c h e d an a r e a of h i g h s t a t i s t i c s i n t h e f i e l d of weak h a d r o n i c d e c a y s , i t becomes i m p o r t a n t t o t a k e p r o p e r a c c o u n t of r a d i a t i - v e c o r r e c t i o n s . The u s u a l p r o c e d u r e i n Ke3 d e c a y s i s t o a p p l y t h e m u l t i p l i c a t i v e c o r r e c t i o n s of G i n s b e r g t o t h e D a l i t z p l o t d i s t r i b u t i o n . T h i s is a m a n i f e s t - l y i n c o r r e c t way of p r o c e e d i n g . I would l i k e t o s t r e s s t h a t t h e b r e m s t r a h l u n g p a r t of t h e r a d i a t i v e c o r r e c t i o n s , K +xevy i s a background, l i k e a n y o- t h e r K d e c a y mode, which s h o u l d be removed l i k e any o t h e r background. I f a n e x p e r i m e n t e r s o u g h t t o remo- ve a background due t o , f o r example, K;

-,

srT$:v

,

by i n t e g r a t i n g o v e r t h e f our-momenta of t h e rro and v and t h e n a p p l y i n g a p e r c e n t a g e c o r r e c t i o n a s a f u n c -

+

^-

t i o n of n- and ;I+ e n e r g i e s , h e would be r i d i c u l e d . T h a t , however, i s e x a c t l y t h e m i s t a k e one makes when one u s e s t h e G i n s b e r g c o r r e c t i o n s . The e x p e r i m e n t a l a p p a r a t u s a n d t h e k i n e m a t i c c u t s made w i l l h a v e a d i f f e r e n t e f f e c t o n t h e b r e m s t r a h l u n g background i n e a c h e x p e r i m e n t , a n d t h , i s must be t a k e n i n t o a c c o u n t f o r e a c h i n d i v i d u a l e x p e r i m e n t . T h e r e i s a n o t h e r

C1-88 V. SOERGEL

r e l a t e d p r o b l e m h e r e t o o . G i n s b e r g ' s c o r r 2 c t i o n s a s - sume t h a t KL + z p q e v e n t s w h i c h o r i g i n a t e o u t s i d e t h e K

-

^zpv k i n e m a t i c b o u n d a r y a r e n o t i n c l u d e d

L

on t h e D a l i t z p l o t . S i n c e t h e e x p e r i m e a t d e t e c t s on- l y t h e n a n d p i n t h e l a b . , h o w e v e r , a n d i t t r a n s - f o r m s t h e b r e m s t r a h l u n g e v e n t t o t h e c e n t e r of mass u s i n g t h r e e - b o d y k i n e m a t i c s , i t may, i n f a c t , i n c l u d e t h i s r a d i a t i v e e v e n t i n t h e D a l i t z p l o t . I n summary.

I know o f n o d e c a y e x p e r i m e n t , w h e t h e r c o u n t e r of b u b b l e c h a m b e r , t o w h i c h a ? u r e l y m u l t i p l i c a t i v e r a - d i a t i v e c o r r e c t i o n may b e p r o p e r l y a p p l i e d .

+ -

7 . -

<

^{-) p 1'}

T h e C o l u m b i a - B r o o k h a v e n g r o u p ( C a r i t h e r s e t a l . , p a p e r n C 1 7 7 ) r e p o r t e d o n a new i n v e s t i g a t i o n of t h i s d e c a y , p c r f o r m e d a t t h e AGS. T h e y u s e d t h e e x p e r i m e n - t a l t e c h n i q u e e m p l o y e d by C a r i t h e r s e t a l . ( P h y s . Rev.

L e t t .

2

( 1 9 7 3 ) 1 3 3 6 ) w i t h some m o d i f i c a t i o n s t o f u r - t h e r s u p p r e s s t h e b a c k g r o u n d . T h e a n a l y s i s y i e l d s t h r e e e v e n t s s a t i s f y i n g c r i t e r i a f o r

-

^;p- d e c a y . T h e m i s s i n g mass s p e c t r u m o f t h e s e e v e n t s , t o g e t h e r w i t h t h c o n e of t h e s i x e v e n t s r e p o r t e d e a r l i e r ( s e e r e f e r e n c e ) a r e d i s p l a y e d i n f i g u r e 6 .

K:--r p + p - ( I ) 6 EVENTS K

: 4 p + p -

(II)

3EVENTS

+

- F i z . 6 . - > l i s s i n g m a s s s p e c t r u m f o r K L + p 11 e v e n t s . YK r e p r e s e n t s t h o m a s s o f KL a s m e a s u r e d i n l a c k e x - p e r i m e n t f r o m K

*

d c c a y s .

'The brarichin!: r a t i o s o f t h e two e x p e r i m e n t s a r e i n xood a:,recment, t h e c o m b l n s d b r a n c h i n g r a t i o i s

' S e e summary o f CP v i o l a t i n g p a r a m e t e r s a t t h e e n d of t h i s r e p o r t .

o r , w i t h

TI+

- ⁼

^{2 . 3 0}

* , r =

1 . 1 1 8 10" s e c - I

*

S

8.

-

CP v i o l a t i o n

New e x p e r i m e n t a l r e s u l t s o n t h e C P - v i o l a t i n g a m p l i - t u d e s 51,-

,

o n t h e c h a r g e a s y m m e t r y i n Keg-decay a n d o n t h e K O - l i f e t i m e were c o n t r i b u t e d t o t h e Con-

s

f e r e n c e by s e v e r a l g r o u p s .

8.1.

-

C h a r g e a s y m m e t r y i n K ^L

-

^{xev a n d K L}

^-'

^{q ~ v}

d e c a y s .

8 . 1 . 1

.-

E x p e r i m e n t of t h e CERN- H e i d e l b e r g g r o u p ( G e w e n i g e r e t a l .

,

p a p e r n C 4 2 0 ) .

A p p r o x i m a t e l y 70x bo6 s e m i - l e p t o n i c d e c a y s of t h e n e u t r a l k a o n w e r e s e l e c t e d f r o m d a t a t a k e n i n a s h o r t n e u t r a l beam u s i n g a m u l t i w i r e p r o p o r t i o n a l - c h a m b e r s p e c t r o m e t e r ( F i g . 3 ) e l e c t r o n s a r e s e l e c t e d by a C e r e n k o v c o u n t e r , muons by a p - f i l t e r . T h e c h a r - g e a s y m m e t r y

8:~)

1 ~ ( K O -> e + i [ v - )

-

^{~ ( K O +} e - x + v ) r ( K O + e + F v - ) + T(KO -f e - l ; v )

was m e a s u r e d a s a f u n c t i o n o f t h e K O p r o p e r t i m e i n t h e i n t e r v a l ( 2 <

.;

< 4 0 ) x 1 0 - ~ ~ sec. T h e d a t a f o r Ke3 a n d K a r e i n good a g r e e m e n t . T h e o b s e r v e d p r u ~ r t h e

P

d e p e n d e n c e of t h e c h a r g e a s y m m e t r y i s shown i n Fig.4 o f P r o f e s s o r S t e c h r e p o r t f o r e l e c t r o n s , i n f i g u r e 7 f o r muons.

L

, L l . L . L l

-+

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TAU,,, I O ~ S E C

F i g . 7 . - T h e p r c p r t i m e d e p e n d e n c e o f t h e c h a r g e asym- m e t r y m e a s u r e d by t h e C E R N - H e i d e l b e r g g r o u p f o r t h e d e c a y K O + r,pv

.

T h e c u r v e is i n p e r f e c t a g r e e m e n t w i t h t h e o n e o b t a i n e d f o r t h e d e c a y K O -xev ( F i g . 4 o f tech's r e p o r t ) ; c o n s e q u e n t l y t h e r e i s n o i n d i c a - t i o n t h a t t h e

&--4

p a r a m e t e r i s d i f f e r e n t f o r t h e two t r l n s i t i o n s .

WEAK INTERACTIONS

-

PARALLEL SESSIONS

A t p r e s e n t t h e e l e c t r o n e v e n t s w i t h z > 1 2 . 7 5 ~ 1 0 - ~ ~ s e c and t h e muon e v e n t w i t h 'c > 1 4 . 7 5 ~ 1 0 - ~ ~ - h a v e been

u s e d t o e v a l u a t e

$ =

^{2 ( 1}

-

^1x1') / ( 11-XI') Re e w i t h c o n s i d e r a b l y r e d u c e d s y s t e m a t i c c o r r e c t i o n s a s compared t o p r e v i o u s measurements. The r e s u l t s a r e

8.1.2.- Experiment of t h e Brookhaven - Y a l e g r o u p (H.H. W i l l i a m s e t a l . , p a p e r n 0 2 9 4 ) .

I n t h i s e x p e r i m e n t , t h e l e p t o n s were d i f f e r e n t i a - t e d from t h e p i o n s o n l y t h r o u g h t h e i r d i f f e r e n t t r a n s - v e r s e momentum d i s t r i b u t i o n . T h e p a r t i c l e s t h e n t r a - v e r s e o n l y a v e r y s m a l l amount of m a t t e r , i n f a c t o n l y 293 mg b e f o r e r e a c h i n g t h e l a s t d e t e c t o r , and t h e e f f e c t of c h a r g e d e p e n d e n t l o s s of p a r t i c l e s , i n p a r t i c u l a r p i o n s , i s minimized, t h u s making s y s t e m a - t i c a l a s y m m e t r i e s of t h i s o r i g i n s m a l l . The momentum a n a l y s i s i s made i n a m a g n e t i c s p e c t r o m e t e r u s i n g MWPC's, and t h e e v e n t a n a l y s i s i s done on l i n e . F o r t h e c h a r g e asymmetry, o n l y a combined v a l u e f o r p a n d e i s of c o u r s e o b t a i n e d . The r e s u l t i s

A c o r r e c t i o n f a c t o r of -1.4 had t o be a p p l i e d t o t h e raw d a t a i n o r d e r t o t a k e i n t o a c c o u n t t h e d i l u - t i o n of t h e measured e f f e c t by n o n - l e p t o n i c d e c a y s , a n d a f u r t h e r c o r r e c t i o n of w+10% f o r t h e asymmetry c a u s e d by t h e 293 mg of m a t t e r i n t h e a p p a r a t u s . T h i s l a s t c o r r e c t i o n was d e t e r m i n e d e x p e r i m e n t a l l y by ad- d i n g 5 . 2 g s of m a t e r i a l , which gave a n asymmetry d i f - f e r e n c e of 4 5 . 2 5 5

t

1 . 7 3 ) x 1 0 - ~

8.2

.-

K -t 2 % d e c a y L

8.2.1.- The C o l u m b i a - B r o o k h a v e n group (D.R. Nygren e t a l . , a b s t r a c t nok216) h a s r e p o r t e d on a new d e t e r - m i n a t i o n of t h e p h a s e a n g l e 9 of t h e C P - v i o l a t i n g

t -

a m p l i t u d e q

.

I n a r e g e n e r a t i o n e x p e r i m e n t ,

+-

( + + - + +p)

,

where 9 i s t h e r e g e n e r a t i o n p h a s e , was P

e x t r a c t e d from t h e 5 - K i n t e r f e r e n c e p a t t e r n ( F i g . 8 ) . S

The r e g e n e r c - t i o n p h a s e was e v a l u a t e d froin t h e K -K L S i n t e r f e r e n c e i n Keg and KID d e c a y d 3 t a t a k e n c o n c u r - r e n t l y w i t h t h e K + m d a t ~ . The r e s u l t s of t n e ex- p e r i m e n t

,

r e p o r t e d t o t h e C o n f e r e n c e , which i s d e - p e n d e n t on t h e v a l u e of

am

i s

The e r r o r i s m a i n l y due t o t h e u n c e r t a i n t y i n t h e re- g e n e r a t i o n p h a s e .

8.2.2.-The CERN- H e i d e l b e r g g r o u p (Geweniger e t a l . , p a p e r n 0 4 1 9 ) h a s measured t h e t i m e d e p e n d e n c e of t h e

21r INTENSITY (4-10 G E V )

I

EXPEH:MENTLL POINTS NO INTERFERENCE

, l I i ~ r f ,

I -

1 I ' L 1

I

^{1 ,}

Ffi3PEH T l l i l E x 10-~0 Sec

F i g . 8 .

-

The t i m e d e p e n d e n c e of t h e K O + Z K d e c a y o b s e r v e d by Nygren e t a l . ( ~ o l u m b i a - B r o o k h a v e n ) i n a r e g e n e r a t i o n e x p e r i m e n t .

i n t e r f e r e n c e i n t h e K+; d e c a y mode between KS a n d K mesons i n a s h o r t n e u t r a l beam a t t h e CERN PS

L

a c c c l e r a t o r . S t a t i s t i c s a r e 100 t i m e s l a r g e r t h a n t h o s e of p r e v i o u s e x p e r i m e n t s . From a f i t t o t h e o b s e r v e d t i m e d i s t r i b u t i o n , t h e m a g n i t u d e and p h a s e of t h e a m p l i t u d e r a t i o

\-

¹ (7i'x-l~~

)

/ ( X + < / K ~ ) and t h e KS l i f e t i m e a r e d e t e r m i n e d

Ts z ( 1 . 1 1 9 t . 0 0 6 ) x 1 0 ~ ~ s-'

The e r r o r s q u o t e d i n c l u d e s y s t e m a t i c u n c e r t a i n t i e s . An i n d e p e n d e n t measurement of I q

)

i s o b t a i n e d from

+ -

t h e b r a n c h i n g r a t i o r(KL + K';) /

r(% -,

x e v ) :

T h e p h a s e measurement is s t r o n g l y c o r r e l a t e d t o t h e mass d i f f e r e n c e &n

,

t h e r e s u l t i s t h e r e f o r e g i - ven a s a f u n c t i o n of &n

C o r r e c t i o n s d u e t o t h e p r o p a g a t i o n of t h e k a o n s i n t h e a p p a r a t u s , l i k e s c a t t e r i n g and r e g e n e r a t i o n a r e t a k e n i n t o a c c o u n t ( F i g s . 9 a n d 1 0 , and F i g . 5 of P r o f e s s o r S t e c h ' s r e p o k t ).

8 . 3 . - The f o l l o w i n g c o m p i l a t i o n of e x p e r i m e n t a l r e - s u l t s on t h e p a r a m e t e r d e s c r i b i n g C P - v i o l a t i o n h a s been p r e s e n t e d t o t h e s e s s i o n by H . Wahl.

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