Proceedings of the Fourth Hawaii Topical Conference in Particle Physics (1971) 9780824885977

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PROCEEDINGS of the

FOURTH HAWAII TOPICAL CONFERENCE IN PARTICLE PHYSICS (l97l)

Edited by

D. E. Yount and P. N. Dobson

CONTRIBUTORS J. W. Cronin

J. D. Bjorken

G. H. Trilling

W. R. Frazer

Copyright ©

1 9 7 2 by The All

Library

of C o n g r e s s ISBN

Manufactured

University

rights

Press

of

Hawaii

reserved

Catalog

Card

Number

71-188984

0-8248-0210-1

in the U n i t e d

States

of

America

CONTENTS Preface

vii

WEAK I N T E R A C T I O N S AND C P - V I O L A T I O N James I. II.

THE I N T E R M E D I A T E FUNDAMENTAL TIONS

W.

-

EXPERIMENTAL

Cronin

VECTOR BOSON

3

P R O P E R T I E S OF WEAK

- SOME I N V E S T I G A T I O N S

INTERACBY

DIVERSE

TECHNIQUES III.

33

P R O P E R T I E S OF WEAK I N T E R A C T I O N S - SOME INVESTIGATIONS

BY

HIGH-ENERGY

TECHNIQUES IV. V.

62

CP V I O L A T I O N - E X P E R I M E N T A L THE K L + y " V

SOME T O P I C S

STATUS

80

PUZZLE

147

IN WEAK AND ELECTROMAGNETIC James D.

INTERACTIONS

Bjorken

INTRODUCTION I.

187

QUANTUM-ELECTRODYNAMICS J Jy M

STRUCTURE

IN WEAK

HIGHER-ORDER-WEAK II.

LIGHT-CONE

INTERACTIONS

189 PROCESSES;

HADRONS OBSERVED

. . . .

211

COMMUTATORS; MODELS OF THE

STRUCTURE IV.

T E S T S OF

INTERACTIONS:

PHENOMENOLOGY OF D E E P - I N E L A S T I C NO F I N A L - S T A T E

III.

TESTS;

HADRON F I N A L PROCESSES;

FUNCTIONS STATES GENERAL

i i i

231

IN

DEEP-INELASTIC

CONSIDERATIONS

. . .

242

V.

INCLUSIVE

PROCESSES

TRANSVERSE

SOME

ASPECTS

II.

DIFFRACTION

VERY

HIGH

MOMENTUM

OF

261

STRONG

George I.

AT

H.

INTERACTIONS

Trilling

PROCESSES

326

I.

Introduction

326

II.

Elastic

327

III.

Inelastic

THE

SEARCH

Diffraction

FOR

Diffraction EXOTIC

I.

I n t r o d u c t i on

II.

Total the

III.

IV.

375

Cross

Sections

for

System

Phase-Shift KN

RESONANCES

375

Channel KN

335

376

Analysis

for

the

I = 1

System

380

Phase-Shift

Analysis

for

the

I = 0

System V.

Remarks in

KN

386 on

Inelastic

States

Produced

Interactions

VI.

Conclusions

VII.

Other

391 393

Manifestations

of

Exotic

Channels III.

SU(3),

DUALITY

394

AND

EXCHANGE

DEGENERACY.

.

423

I.

Introduction

423

II.

Two

Examples

425

III.

The

Elastic

Scattering

SU(3)

Relations IV.

t-Channel

432

SU(3) iv

Relations

444

IV.

EXPERIMENTAL

ASPECTS

OF

MULTIPARTICLE

PHENOMENA

465

I.

Introduction

46 5

II.

High-Energy

Cross

III.

High-Energy

Multiplicity

IV.

A Simple

Sections

Example o f

465 46 7

Multiparticle

Production V.

Energy

469

Dependence

of

Secondary

Spectra VI.

471

Forward-Backward Non-Leading

V.

Asymmetries

for

Secondaries

473

VII.

Scaling

476

VIII.

Factorization

477

SOME T O P I C S

IN BOSON SPECTROSCOPY

. . . .

I.

Introduction

494

II.

The 2 + N o n e t

494

III.

Low-Energy

Kir and

TTTT

Spectroscopy

(£ 1 GeV) IV.

500

Higher-Energy

TTTT

and Kir S c a t t e r i n g .

MULT I - H A D R O N I C REACTIONS AT HIGH William I. II.

494

R.

ENERGIES

Frazer

INTRODUCTION GENERAL

507

537

FEATURES OF MULT I PART I C L E

REACTIONS

538

A.

Some V e r y

General

B.

Longitudinal

C.

Inclusive

Observations.

Kinematics

Spectra; v

Scaling

. . .

538 539 545

D.

Mueller Analysis

of

Inclusive

Reactions E.

Short-range

F.

Partial

Correlation Hypothesis.

Cross Sections

plicity III.

551

and

Distributions

The C h e w - P i g n o t t i

572 .

576

Diffractive-Fragmentation

Picture;

Hwa's Model C.

Statistical

576

Multiperipheral

Model B.

562

Multi-

SOME MODELS OF MULTIPARTI CLE REACTIONS. A.

.

581

Thermodynamical

vi

Model

. .

585

PREFACE The Physics Campus

Fourth was

through

the G r a d u a t e Commission, Physics

2-13,

University

Conference

of H a w a i i

Topical

held August

o f the

The

Hawaii

was

which

in

the

Particle

Manoa

Hawaii.

from

by the

University

Dean Wytze

Gorter

by the U. S. A t o m i c

supports and

1 9 7 1 , on

sponsored

a grant

Division;

Program;

of

Conference

the

local

of

Energy

High-Energy

by the U. S. N a t i o n a l

Science

F o u n d a t i on. The

sixty

physicists

met each morning again The

each

and

afternoon

principal

J. C r o n i n ,

but summaries

Physics

Report

were

given

S. F. T u a n , provided Chong,

seminars

are

talks,

contained

beyond

both

was

joined

seminars.

a n d W.

Frazer;

volume.

included

of

Notes

here,

by the

in a U n i v e r s i t y

hard

Professors

guidance

the C o n f e r e n c e

ably

met

Professors

prepared

past directors

essential

the call

not

and

authors Hawaii

( U H - H E P G - 5 1 1 - 1 0 9 - 7 1 ).

possible.

uted countless

by

in this

A n u m b e r of p e o p l e w o r k e d Conference

Conference

lectures

G. T r i l l i n g ,

are p r e s e n t e d

of t h e s e

are

principal

the

to h e a r c o n t r i b u t e d

J. B j o r k e n ,

contributed

themselves,

two

lectures

their papers

of the

for

attending

hours

of d u t y . by

of the

vi i

time,

once

Mrs.Caroline

again

cheerfully

contriband

effort, Mrs.

Roseman.

and

Conference,

and s u p p o r t .

In this

Mrs. J e a n

this

V. Z. P e t e r s o n

Secretary, of h e r

to m a k e

We a l s o

Chong wish

to acknowl edge the a s s i s t a n c e students

and s t u d e n t

Finally,

we are p a r t i c u l a r l y

lecturers,

lectures,

but a l s o f o r in a l l

grateful

not o n l y f o r t h e i r t h e i r a c t i v e and

phases of the

1971

vi i i

to the

suberb enthusiastic

Conference.

D. E. Yount P. N. Dobson,

December 7,

graduate

helpers.

principal

participation

p r o v i d e d by

Jr.

WEAK

INTERACTIONS

AND

James Enrico

CP-VIOLATION

W.

Fermi

* This

research

Energy

supported

Commission

Foundation.

and

EXPERIMENTAL*

Cronin Institute

Uni versi ty of Chicago,

-

Chicago

Illinois

in p a r t by the

by the N a t i o n a l

U. S. Science

Atomic

LECTURE I THE One

of the c e n t r a l

s t u d y of f o r the Active when

INTERMEDIATE

the w e a k boson

that mediates

of h i g h - e n e r g y

has

for

been

could

in

the

the

search

interaction.

this

o u t t h a t the

neutrinos

goals

the w e a k

searches

pointed

BOSON

experimental

interactions

experimental

it w a s

VECTOR

object

direct

began

interaction

be o b s e r v e d

at

existing

accel e r a t o r s . ^ At

low e n e r g i e s

described

by a c u r r e n t H

with

G = 10

analogy expect field

would

-5

with the

/m

2 P

w

.

interactions

x current

Here m

true

vector

interaction massive

nucleón

mass.

interaction

to be m e d i a t e d

quanta would The

boson.

well

interaction:

is the

P

are

J+(x), v

= - 4 J (x) /2 y

the e l e c t r o m a g n e t i c

B^, whose

mediate

the w e a k

fundamental

one

by a

be the

In might boson

inter-

interaction

become H W = 3g J V (x) B V (x). Two

currents

are

coupled

vector-boson

propagator.

tinguishable

from

coupling described

involves

to the m a s s normally charged

of the

called since

the

boson.

the w e a k

current

physical

momentum

W and

intermediate-

Such a coupling

the d i r e c t

above when

by an

x

The

currents 3

being

small

intermediate

is p o s i t i v e l y are

or

indis-

current

process

transfers

is

compared boson

negatively

charged.

The

is

small

coupling

constant g is

r e l a t e d to the

Fermi

c o n s t a n t G by

„2 w

/r

One can see t h a t the p r i m i t i v e becomes q u i t e s t r o n g

for large M .

expect semi-weak p r o c e s s e s duced to be q u i t e

f o r semi-weak Several

Hence one can

i n which a r e a l

important

very high energies

interaction

if M

is

W is

large.

Of

are r e q u i r e d to reach the

authors

to p r e d i c t i o n s

w

=

V f

i n some d e t a i l

(T7?>2=

3 7

'3

p a r t of t h i s

the e x p e r i m e n t s for

GeV/c2

"2

l e c t u r e we s h a l l t h a t have been

feature

the e x i s t e n c e

were i t to e x i s t .

review carried

common to a l l

I n a l m o s t e v e r y case the or n o n - e x i s t e n c e

depends on knowledge o f what i t s

following

led

the W b o s o n .

an i n t e r e s t i n g

these searches. concerning

type have

i s merely a s p e c u l a t i o n .

I n the f i r s t

There i s

of t h i s

electric

that

Of c o u r s e , t h i s

out s e a r c h i n g

threshold

have p o i n t e d out t h a t a n a t u r a l

Recent c o n s i d e r a t i o n s

M

course,

processes.

s t r e n g t h f o r g might be of the o r d e r of the c h a r g e e.

pro-

The W+ i s

W

p

information of the W

properties

would be

expected to have

decay modes: + v , U 4

of

the

1.+ W -v e + J. + ve, W + -»- h a d r o n s , _ 3 with

similar

W for

the

G

T

has

M

w

short

lifetime

The

difficult

pretations

shared The

beams

w

AGS +

1

the

is

Ge

2

V/c ).

not permit direct must

width

be

for

r e l y on

obser-

inferred

hadron

Hence,

= r(M + l e p t o n ) r(W -* all m o d e s )

_

equally

and

of

the

decay inter-

assumptions

ratio

assumed

produced

W+

+ Z

partial

to be ^ 0 . 5 ,

between

first attempts

Brookhaven v

does

=

to c a l c u l a t e .

the b r a n c h i n g R b

v^

(M

of m o s t e x p e r i m e n t s

B is g e n e r a l l y

lifetime

9 s e c

of the W, so its e x i s t e n c e

been

being

The

can be c a l c u l a t e d

10

*

its d e c a y .

about

.

17

= 7 r h

This

from

for U

leptonic modes

1

vation

decay modes

muon

to s e a r c h

by the d e c a y

and at the CERN + Z is the

. the

and

f o r the W

The

beams

b)

5

employed at

the

reaction

r e s u l t of two

a)

modes

electron.

of p i o n PS.

lepton

diagrams:

The

diagram

a)

The

cross

f o r the

uncertainty

the W.

The

The transfer Under

this

produced

condition so t h a t

in the

incident

strongly + v

E _ ^ y

E

forward

neutrino

polarized

is e m i t t e d

n o t be

given

on the

by Q

a n t i - p a r a l l el .

2 M /2 E . w v

of E^ is the W +

the W +

In the

tends

in the W +

backward

shell.

taken

is

Furthermore,

is l e f t - h a n d e d ,

of

momentum

. ^ mi n

share

direction.

which

except

momentum

the

(m,,/M,,), a n d ]i w

v

a

coherent

on the m a s s

largest

, the a n t i - l e p t o n ,

handed,

or m a y

largest when

the

with

mass

magnetic moment

depending

to Z is a m i n i m u m

by the W +

y+

may

is

the

can be c a l c u l a t e d

to p u t the p +

W production

virtually

upon

interaction

of a p o s s i b l e

nucleus

required

The v^

is c a s t

section

interaction

the e n t i r e

transfer

the

The

by an e l e c t r o m a g n e t i c

nucleus.

over

important.

into W + y ~ .

dissociates shell

is m o s t

is

decay

to be

since

W + ->

right-

center-of-mass

system. Thus slow

negative

lepton ture

a characteristic

at l a r g e

in the

case

s l o w y" w i t h having

very

kinematics great

muon

detail Five

of W +

a large

of W +

production

and a moderately

laboratory

little

of W +

release

transverse

production

in a r e c e n t

have

paper

distinct W searches

6

into

would

be a

The

discussed

by C l i n e have

signa-

hadrons

momentum. been

been

very

positive

A possible

to h a d r o n s

decay

energy

net

angle.

fast

is a

et

in

al.4

carried

out

with

neutrino

these

1 summarizes

is t y p i c a l

They

look

of the

muon.

Their

thick

Al.

between

ground

spark

the

the r e s u l t s

showers

results

chamber was which

shower.

from

seen To

The

the m o r e

of

cross

ratio

to

above.

e t al.

the m u o n

needs

B.

to the

The

from

the

the p i o n

1 shows

t h a t an e s t i m a t e

at the

(1)

and

can

absolute

observing infordata.

0.5. number

of the

by

the

noted

of the

edge.

the

of

(3)

section

This

B =

function

is g e n e r a t e d

7

and

production

ratio

high-energy

spectrum

by

decays.

by p a r t i c l e

sensitive

shape

spectrum

Figure

of the n e u t r i n o

back-

know:

cross

a branching

is a v e r y

to

uncertainties

determined

supplemented

shape

photon-

v^ + n

spectrum,

assumed

spectrum

a

muon-electron

authors

of e v e n t s

and a

reaction

neutrino

o f the n e u t r i n o

spectrum

mation was

a

distinction

f o r the W as a f u n c t i o n

leptons

subject

normalization

a

of the t y p e

section

be c a l c u l a t e d Burns

with

quarter-inch-

is a p o t e n t i a l

limit, one

(2) the a b s o l u t e

branching

experiments.

experiment.

set a lower

production

b u i l t of

shower

prolific

al.,5

et

be c o n s i s t e n t w i t h

permitted

latter

No e v e n t s

in the

of Burns

in a s s o c i a t i o n

that would

an e l e c t r o n - i n i t i a t e d

Y " + p + TT°.

mass,

track

plates,

initiated

The

I gives

neutrino-production

for e l e c t r o n

non-interacting

were

Table

searches. Figure

and

beams.

This

exact part

K-meson

decays.

Lack

of, k n o w l e d g e

is one of the

largest

of the n u m b e r

of e v e n t s

A CERN the W m a s s energy

slow p".

The

was

small.

quite

events

latter

Thus

case

since

it c a n

be c o m b i n e d

set a l i m i t on

W by m e a n s

B = 0.

being

with

high

a limit

slow

consistent with of the a b o v e

able

is an the

to s e t a

previous

a type

limit

important

independent

on

visible

a non-interacting

This

the W m a s s

spark-chamber of

its

established

tracks

produced

in the

from muons

potential

p a t h of s e v e r a l

t r a c k , as well

chamber

result

result

of the

to

branching

as

this

searched The

two

latter

interaction.

by t h e i r technique

a careful length

the

limit

non-interacting

interaction

interaction

for

strong

Pions inter-

requires lengths

calibration in the

a for

of

the

spark-

m a t e r i al.

The states

pi on

for

neutrino

In p r a c t i c e ,

also

mode.

by s e a r c h i n g

distinguished

effective

group

decay

actions.

each

prediction

B. A CERN

are

with

they were

in the

was

obtained

n u m b e r of c a n d i d a t e s

on M w

ratio

group

coupled with

the

in the

spectrum

expected.

by e x a m i n i n g

track,

high-energy

uncertainties

bubble-chamber

in h a d r o n s

negative

of the

combination

of the

t h a t M,, ^ 1.8 G e V / c 2 w

independent The

of the m o d e

upper

of

l i m i t on M

results with

90%

given

in T a b l e I

confidence,

decay. t h a t can

8

be a c h i e v e d

by

neutrino

production

neutrino

energy

these

limits

CERN

permits

In the n o t u n l i k e l y suffers

to e s t i m a t e

more

than

result

can t h e r e f o r e for

ble.

Here o i s

carried

first out

the A r g o n n e excess flux

expected

characterized ^

M

w

/2.

reduced

since

can

mass

protons).

result,

section.

section Q

range

in

this

no r e l i a b l e

A

varied

by

negative as

an

upper

kinematically cross

way

Specifi-

have

be e x p r e s s e d

us aing

from pion by m u o n s

incident

a n d his

basic

large

accessi-

section

in

angles decay.

with

protons

to

look

exceeding This

large

was

collaborators

idea was

from pion

for

the

excess

would

transverse

greatly

of the p i o n s

before

decay.

momentum,

falls the

high-transverse-momentum 9

rapidly

number

of

muons

an

be

momenta

can be

spectrum

at

muon

decay

the p i o n

transverse give

the

collision.

by a b s o r p t i o n

increasing which

only

The

The m u o n s

Further,

been

cross

by M. L. G o o d

at

at

of W's

incident

the W p r o d u c t i o n

ZGS.

that

a broader

of m a g n i t u d e .

W search

of m u o n s

over

has

cross

the m a s s

nucleon-nucleon The

production

there

of t h i s

four orders

on a w B

improved

e v e n t of a n e g a t i v e

the p r o d u c t i o n

limit

the

for

f o r 30 GeV

because

cally, estimates

highest

it is u n l i k e l y

one to s e a r c h o

(up to 6 G e V / c

method

and

by the

PS.

use of p r o t o n s

principle range

available,

limited

can be s u b s t a n t i a l l y

A G S or a t the The

is s h a r p l y

with pions is

greatly

decreased.

It is c l e a r

of W d e t e c t i o n

improves

course

is k i n e m a t i c a l l y

that M w

Figure ment.

2a s h o w s

They

production

simply angle

absorber close m i t t e d was

This

to the

measurements pion

production

and

a mass

2c.

also

be

2 - M

Here

of p r o d u c t i o n

neutrino

shield.

of b o t h

fixed thickness.

of

these

observed

came

l i m i t on

the

originated

was

of the p r o d u c t i o n

target

Brookhaven could awB

a small

be e x p r e s s e d

in a

by a

distance

as

as

a

the thick The

displacement upstream.

also y i e l d e d

- "34 ? cm / n u c l e o n ,

10

in

shielding.

evaluated

experiment

* 4x10

the

at

measured

a n d of d e p t h

yield

decays

out

flux was

angle

The muons

carried

against

result which

at a

The

- 3.

target placed directly

The

Fig. 2b.

set:

the m u o n

function

from pion

an

trans-

of a b s o r b e r

an u p p e r

experiment was

Brookhaven.^

at a

flux

in

muons

experi-

by p l a c i n g

measured

Analysis

that only

of

4xlO~34cm2-sr~1-GeV1/nucleon,

range

A similar

done

is s h o w n

t h a t all

of a W" c o u l d

muons

The muon

as a f u n c t i o n

indicated

B ^ for

flux was

in Fig.

decay

and

providing

f o r the Z G S

negative

target.

technique

accessible.

This was

then measured

is s h o w n

from

observed

(4 G e V / c )

increases,

the a p p a r a t u s

of 2 0 ° .

negative-particle momentum

as M

t h a t this

a

negative

p for a m a s s section

range

2 ^ Mw

is q u o t e d

b a s e d on a m o d e l

from

for W p r o d u c t i o n .

limit applies

particles

of e i t h e r

have

recently

to

R.

This

was

by i n c i d e n t thereby

low d e n s i t y A model

and

zation y

pion y

decay

this

was

to p a r i t y

strong

+

of a v i r t u a l

The experimental was

photon,

from

Forward

vector

muons the

tail

meson

longitudinal in

Muons

s o u r c e will

electro-

derived

be r e f e r r e d

from to

photon.

apparatus

designed

polari-

> while Any

conservation

heavy

suggest-

The

1•

any

at

density.

which

= =

target

varied,

their source.

interactions.

such e l e c t r o m a g n e t i c

longitu-

at h i g h

or f r o m a h i g h e r - m a s s to h a v e

protons.

decay

direction.

from a virtual

magnetic

apparatus

pion

rate

have a^'P^

due

the

constructed

on

by

sensi-

in a h e a v y

from

from W decay

and

and more

density was

a helicity

polarization

This

rate

depended

n o t be e x p e c t e d

as d e c a y s

produced

have

might come

collaborators^

to m e a s u r e

in the f o r w a r d

of the p m e s o n ,

any

a n d his

target

the muon

of the m u o n s

forward

would

The

of W p r o d u c t i o n

from

which

of m u o n s

suppressing

ed l a r g e y i e l d s

noted

of W

for W p r o d u c t i o n

designed

protons.

enhancing

It s h o u l d be

sophisticated

to s e a r c h

polarization

cross

measurements

the p r o d u c t i o n

K. A d a i r

tive experiment

dinal

A total

sign.

carried out a more

experiment

.

the d i f f e r e n t i a l

that this

More

* 6 GeV/c

is s h o w n

to m e a s u r e 11

in Fig.

the

flux

3a. of

muons

produced

of the the

Further,

could

lyzing

p o w e r of the

the m u o n s

to

was

location

was

not

decay

available

muons

of

positive

The

small

of the

muon

f i e l d as

flux

f o r the

the

of

ana-

directly caused

target.

selected same

the m u o n s

of

In

production

because

of

trajectory

appabeam

this can

the

Nor

since

multiple The

amount

pions.

the

of the

in the s h i e l d i n g .

properly

follow

source

because

a m o u n t of p i o n

spurious

magnetic

known

far upstream

a small

necessarily

of the

field which

the e x a c t

to a v e r y

to a l a r g e

of t h e s e

density

was m e a s u r e d

magnetic

experiment

sensitive

path

polarization

polarimeter

of the m u o n s

interacting

as o f the

function

precess.

muons

scattering

as a

in a p o l a r i m e t e r .

an e x t e r n a l

In t h i s observed

the

be m e a s u r e d

by a p p l y i n g

ratus

direction

s i g n of the m u o n , as well

target.

muons

in the f o r w a r d

lead

long

is the

they

sign

do

not

through

the

originating

from

the

target. Figure

3b s h o w s

function

of the

incident

beam was

decays

of pions

energy

as well

cles

and

evidence

reciprocal 28 G e V .

as

from

the

y-rays.

to a f i n i t e

for direct

of 2 5 - G e V

target

value

production

12

decays

fact at

as a

The

originate

the h i g h e s t

prompt The

muons

density.

The muons

produced with

virtual

extrapolate

the y i e l d

that

from

possible of W

the

infinite

if u p s t r e a m

parti-

yields

density pion

is

decays

are n e g l e c t e d .

The authors

for the diffuse

target is high, whereas

small

for the dense target.

argue that the e x t r a p o l a t e d

y+/y~

note that the ratio

it is very

From this fact they negative y i e l d is a true

prompt y i e l d , while the excess positive y i e l d is a measure of the possible c o n t a m i n a t i o n duced by scraping

of pions

the beam far u p s t r e a m of the

The latter a r g u m e n t assumes

protarget.

that the sign of the

produced upstream is properly

muons

designated.

The e x t r a p o l a t e d y i e l d s at infinite

target

density are found to be: ^ ^

) =

)

(4.3±0.6)xl0"35cm2-sr"1-GeV"1/nucleon,

= (2.7±0.6)xl0"35cm2-sr"1

The excess of y + W+

production.

G e V - 1 /nucl eon.

is a s s u m e d to give an upper limit to This y i e l d , when combined with

the

production m o d e l , gives a limit of CT,,B ^ w

6xl0"36cm2.

The prompt y i e l d of y~ is c o n s i d e r e d

to be a real

effect, being the negative c o m p o n e n t of y - p a i r s coming

from the decay of a virtual

this number represents

an upper

photon.

pure.

least,

limit.

The second phase of the e x p e r i m e n t , the part, failed because the signal

At

was not

elegant

sufficiently

Figure 3c shows the precession of the muon

asymmetry

for the two extremes of density.

13

The

polarization Figure

is l a r g e

3d g i v e s

the o b s e r v e d

t i o n of r e c i p r o c a l the f u l l - t a r g e t possible

dilution

do

for

the

decay

compared

The

pion

to the

precise

negative decay.

densities

polarization It is a p i t y

the

of h i g h

polarization

ciently muons,

might

since

transverse

transverse

very

to

pions

of

are

data not

it. consistent for

with muons

does

not

polarization. effect.

better

momentum. have

the s o u r c e

The

if

performed

In t h i s been of

case,

suffiprompt

are

produced

with

of y - p a i r s

produced

in

high

momenta.

The o b s e r v a t i o n nucleus

identify

few

they

large

might

15%

The

expected

fared

measurement

sensitive

point.

of the

have

from

to a 15%

that nature

expect a very

experiment

muons

are

At

high-density

and

to e s t a b l i s h

muons.

to o n l y

a t the

func-

of m u o n s

at most

such a dilution,

There, one would

with

amounts

low-density

p e r m i t an e a s y m e a s u r e m e n t

entire

fraction

density.

as a

the 2 5 - G e V

corresponds

d a t a a t all

large

no c h a n g e w i t h

polarization

of the p o l a r i z a t i o n

sufficiently

from

density,

This

not exclude

the

density

heavy-photon

the y + y i e l d .

point

and shows

collisions

W-production

cross

calculation.

The

of a W in an

permits

a better estimate

section

than

cross

inclusive

section

a purely f o r the

reaction,

p + Z ->• W +

+ a n y thi n g ,

14

protonof

the

theoretical production

can

by C V C 1 2

be r e l a t e d

to

the i s o v e c t o r

part

of

*

p + Z

y

+

anything

I-»- y + The mass

cross

section

is r e l a t e d

of the

same

physical

production

relationship

implies

non-existence

for W p r o d u c t i o n

to the

effective

+ y~.

production mass

of

as

that detected

about

of the W or w h a t

given

of virtual

two m u o n s .

nothing

at a

y-rays by

Of c o u r s e ,

the the

the e x i s t e n c e

its m a s s

might

CVC or

be.

T h e p r o d u c t i o n of y - p a i r s by p r o t o n s s t r i k i n g u r a n i u m a t 30 GeV has a l s o b e e n m e a s u r e d . 1 3 F i g u r e shows

the c r o s s

model-dependent quoted

is s o m e

section

da

+

y M

uncertainties. fraction

production

the

limited

to be * 65 m r a d a n d 12

GeV.

Lederman relation

as an

0 is the

constant, cross

and

section

A crucial is t h a t

angle

Pope

because

have

unequality

virtual

section y

was

the e n e r g y

4a

evaluated

which

had

/ V

2

d

V y d m

is the y - p a i r

assumption

as m e a s u r e d

in g e n e r a t i n g y-ray

fine-structure production on

this

is p r o d u c e d

p a r t of the e l e c t r o m a g n e t i c 15

CVC

\ /isovector'

da^+^_/dm

nucléon

the

states:

a n g l e , a is the

per

large

section

cross

Cabibbo

the v i r t u a l

isovector

cross

total

of the

rather

14

> A 3G " 2 T Â T Z T /2

% where

and

The

of the

because

to e x c e e d

_/dm with

4

uranium. inequality

only

by

the

interaction.

If the no

entire

relation

expression

production

could

The

vector not

the

vector

5 then the

such

importance

it s e t s

interesting

ments

to s e a r c h

of an a c t u a l

section

at NAL

by s c a l i n g

the

one

of

the

a function

The

cross

of W mass.

an e q u a l i t y

for

the

axial

part

cross

section

and

If the

present

limit,

the

should

the

CVC

by w h i c h

with

advance

above

finds

does

simply

assumption

t h a t M,, > 4 . 5 G e V . w

cross

for

part,

B =

0.5,

Considering

probably

be

cautious

limit.

a scale

W-production

most

a

the

one

limit of

taken with

uncertainties,

The

the

total

indicates

in a c c e p t i n g

that

as

part.

~36 2 - 6x10" cm , is

all

When

p a r t of t h e W p r o d u c t i o n .

to the

Fig.

lower

is e s s e n t i a l l y

in the

isoscalar

i sovector

for W production

interfere

adds aw

5 shows

relation

the

numerically,

M3 w

a, * 0 . 0 9 w

section

by

be e s t a b l i s h e d .

is e v a l u a t e d

Figure

went

relation, one can

section. respect

the

Its

to the

W at higher

measurement

energies, Brookhaven

one

however,

better

of

energies.

of t h e y - p a i r

can e s t i m a t e

y-pair

estimate

application design

is

its

experiment.

is

experiIn cross yield This

has

1 5 been

done

fits

the

using

the

Brookhaven

p r o d u c t ion c r o s s CVC

relation.

Drell-Yan data

section

Figures

parton

reasonably can

6 and 16

then

model, The

W-

be e s t i m a t e d

by

7 show

well.

which

the

predicted

the

values

for a w

f o r NAL a n d

It is i n t e r e s t i n g machines,

the

(1500-GeV

equivalent

25-GeV

= 20 G e V / c

10"35cm2.

a hypothetical

because

3 o f the M w f a c t o r w

noted

that

of 4 x 1 0

30

GeV.

of

in

high-trans-

background

is r e l a t i v e l y

in the C V C

of

small

relation.

Table

experiments.

gives

if the

ring

experiment

The expected y-rays

new

in e a c h

by o b s e r v a t i o n

from virtual

the two

two

have:

NAL a,, ^ w

muons.

While NAL

, we

respectively.

a n d NAL a t 400

5xl0~34cm2,

y-pairs

II c o m p a r e s

2

the

ISR a w ^

the W is d e t e c t e d

verse-momentum

ISR,

protons

lab e n e r g y )

L e t us c o n s i d e r which

the

to c o m p a r e

ISR w i t h

For a v a l u e M w

for

a much

higher

ISR r e a c h e s 100

(a f a c t o r

larger

rate,

it m u s t

its d e s i g n than

be

luminosity

at p r e s e n t ) , it

? can

probably

rate. same

reach

If NAL

unlikely,

reach

the m a s s A large

Fermi-momentum illustrated

of 3 7 . 3

for

a

measurable

boosts

that either machine

have

the W p a r t i c l e .

source

of proposals

It can

GeV. been

Table

of s o m e of t h e m w i t h e s t i m a t e s The

the

the

in Fig. 6.

n u m b e r of e x p e r i m e n t s

sensitivities. collection

the

however,

to s e a r c h

a summary

with

500 GeV, one m i g h t a c h i e v e

threshold,as

seems

at N A L

= 30 G e V / c

attains

limit because

effective

Mw

of t h e s e

submitted 17

to

data NAL.

of was

proposed III

gives

their the

At p r e s e n t o n e that M w

- 1.8 G e V / c

l i m i t and are

very

perhaps good.

discussed

III

sets

leptons.

observe

shows

prospects the W w i t h

are two may

certainty

only

to i m p r o v e

this

the

new

theoretical

be r e l e v a n t

machines

points

to s e a r c h e s

that W particles

be p r o d u c e d

scale

requi re a s i g n i f i c a n t

related

the v a l u e

to the

with mass

by p r o t o n s .

an a p p r o x i m a t e

Recently

been

The

with

for

energy.

can o n l y

experiments

has

.

below which

Table p

relation

can c o n c l u d e

There

the W at h i g h e r

GeV/c

p

The

for a .

> 10

CVC The

b r a n c h i ng rati o to

of the

branching

ratio

B

ratio16

p ( e + + e" hadrons) a /(e + + e - -»- y + + y -1) ' Indications

are

implies

0.5.

B ^

that

Considerations also

give

might

be.

some

this

ratio

is £

of h i g h e r - o r d e r

hint about what

Calculations

of the

K^ -»• y + y

a n d of the

rate

order weak

interaction)

1,1^

weak

interactions

the m a s s

of the W

K L — K^ m a s s

(contribution both

which

require

a

difference

from

second-

phenomeno1o

logical The

c u t o f f A in o r d e r

values

of A r e q u i r e d

respectively. encouragement if M w %

to y i e l d

finite

a r e ^ 4 GeV

Both of these

numbers

and ^ give

to i n t e r m e d i a t e - v e c t o r - b o s o n

A.

18

results. 20

GeV,

some enthusiasts

NOTES AND 1.

B.

Pontecorvo,

(1960);

M.

Soviet

Schwartz,

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T.

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608

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1J5, 830

11.

P. J. W a n d e r e r 729

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13.

J. C h r i s t e n s o n

L. M.

16.

Nuovo

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S. D. 316

Letters

23^

et a l . , P h y s .

Rev.

Cimento

et a l . ,

193

Phys.

Rev.

(1966).

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25,

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University 15.

Rev.

(1971).

Y. Y a m a g u c h i ,

14.

Phys.

C. M. A n k e n b r a n t

12.

1523

et a l . ,

a n d B. G.

(to be

Drell

Pope,

preprint,

Columbia

published).

and T-M. Yan,

Phys.

Rev.

Letters

25,

(1970).

L - F . Li

and

E. A.

Paschos,

Phys.

Rev.

D3>

1 1 7 8

(1971 ). 17.

For a r e v i e w e+e~

18.

beams

of h a d r o n

see

in

r e p o r t of R. W i l s o n ,

of the

Fifteenth

Energy

Physics,

R. N. M o h a p a t r a

production

International Kiev,

colliding P r o c e e d i nqs

Conference

on

1970.

et a l . ,

(1968).

20

Phys.

Rev.

1_71,

1502

High-

ai o e: ai -a •i-

CT*

CTI CTI

O CO

un co

co CTI

"O O)

o LO

o i—

o LT)

o m

o LO

3 io to •=c

o

o V

o

o

o

aj i— -Q -O

aj i— -Q -O

CQ

CQ

o »s

c: o o

ça

E

aj CT •i— c .c a ai i—

tO Q. to

IO Q.

to

21

íro a. en

0 01 CM o

ir> PO

X LO

22

SO) +J to co I O

S3 o x: \ co o o LT)

C O •I— •!-> (0 N

•I—

>

•r+-> •rl/l

'r— Í. 10

CM E O ^ ^

C

IO co i

io co i

o r—

CU

CO

i—

I

o r—

o 1

c

IO VI

ai .c Cû


ld CM

CM

CM

V

V

«3 a£

IO aj 1/1

m i/i

o o .

ai tn

V IO

IO

23

o E * —

FIGURE 1.

Cross-section calculate

2.

a n d flux

a lower

a) A p p a r a t u s prompt

used

calculated sole muon

in R e f .

function

of m u o n s The

on the b a s i s

of a b s o r b e r

through

solid

is

curve decay

is c a l c u l a t e d

on the

a) A p p a r a t u s

used

in R e f .

pion

the p o l a r i z a t i o n of m u o n s

c) P r e c e s s i o n

as

the

11

of m u o n s

solid

to m e a s u r e

that

the

yield

muons.

of t a r g e t

muons

target

The

decay.

as f u n c t i o n

two d i f f e r e n t

as a

assumption

of p r o m p t

of 25-GeV

d) P o l a r i z a t i o n

particles

thickness.

from

for

of

transmitted

of p i o n

negative

come

b) Y i e l d

5 to

source.

muons

and

in R e f .

9 to m e a s u r e y i e l d

absorber.

c) Y i e l d of 4 - G e V / c

3.

used

limit for M . w

spectrum 2

1165 gm/cm

all

data

muons.

b) M o m e n t u m

curve

CAPTIONS

brought

density.

to

rest

densities.

as a f u n c t i o n

of

target

13.

Solid

d e n s i ty. 4.

Measured lines

5.

show

Predicted relation

6.

Predicted 500

7.

cross

limits

due

W-production

section

in R e f .

to m o d e l cross

a n d d a t a of R e f .

dependence.

section

13 for

using

30 GeV

the

W-production

cross

section

for NAL

at

W-production

cross

section

for

at

GeV. 24

CVC

protons.

GeV.

Predicted 1600

dimuon

ISR

E o z1

o H o er o.

o

t-

u

LU CO

>-38

en co O er u z

o I-

o o Q O er

CL

O

CO

O CO

Fig. 1

25

9

SCALE :

?.. '9

feat

Fig.

2a

26

Fig.

27

3a

1/TARGET DENSITY

Fig. 3b

TIME leseci

Fig. 3c

(a)

E^ = 25.1

1

2

3

\/P

T

T

:

T • I

Fig. 3d

28

X

Fig.

4

i

i—

i

i

1

1

E 0 = 30 GeV -33

\

••

nr.• o •-34 t? C wD

' — — • > .

-35

-36

0

i 1

1— 1 1 1 2 3 4 5 6 Mw (GeV/c2 ) Fig.

30

5

1 7

Mh

(GeV/c2) Fig.

31

6

1

1

1

1

1.

•• -31 •• -32

.. _ 37 COLLIDING PROTON BEAMS 55 GeV ••-38 'E Q ' = 1 . 6 TeV -I 0

1 10

1 1 1 20 30 40 Mw (GeV/c2) Fig.

32

7

1 50

60

LECTURE FUNDAMENTAL SOME

INVESTIGATIONS

In this some

of the

actions.

PROPERTIES

II

OF WEAK BY

DIVERSE

l e c t u r e we d i s c u s s fundamental

We will

INTERACTIONS

the

properties

emphasize

-

TECHNIQUES investigation

of w e a k

the d i v e r s e

of

inter-

origins

of

the

i n f o r m a t i on. Bjorken^ leptonic gate.

for w h i c h

sively

stressed

processes

There

The

has

as the m o s t

are o n l y

there

first

the v a l u e o f the

two

is any

fundamental

purely-leptonic

experimental

,\ 1)

y

+

2)

v, + e~ ->- v + e e

e

process, ?

studied.

+

+ v

muon

e

to

investi-

processes

information:

+ v , y e~.

decay,

It is f u l l y

purely

has

been

exten-

consistent with

a

leptonic

c u r r e n t of the f o r m

+ Yg)m•

however,

do not e x c l u d e

modifications

the V-A form v to

interaction. (ay

less

(1 + y g )

than

asymmetry.

substantial

If the + 3y

.16 by m e a s u r e m e n t If

|g| w e r e

purely

of the d e c a y

verse

plane of

direction. they

If s c a l a r

can be as m u c h

contradicting

Further

progress

|3|

o f the

or t e n s o r

spin and terms

30% of the

33

to

in

the

limited

a 30%

the

are

vector

measurements

data,

electron

imaginary,

the e x p e r i m e n t a l

requires

is

electron would occur

the m u o n

as ^

without

is w r i t t e n

(1 - Y 5 ) ) u >

polarization to the

current

The

trans-

electron

permitted, terms

measurements. of the

angular

and s p i n c o r r e l a t i o n s

The muon decay a l s o low e n e r g i e s interaction

cross a(v

measurements the

The t h e o r y

where E^ i s

purely-1epton

has never been

e

+ e") = —

of E v = 1 0 8 GeV

2

TT

the l a b o r a t o r y

directly the

2 E ni % 1 . 5 x l 0 " 4 1 v e

energy o f the

S-wave u n i t a r i t y

out of the q u e s t i o n .

e s t i n g a t low energy because i n t e r a c t i n g with i t s e l f . by a d i s t i n g u i s h e d

at a v a l u e

it arises

mass).

in

The p r o c e s s

this is

There have been

speculations t h a t such a

c o u l d have a c o u p l i n g

from the n o n - d i a g o n a l

Experimental

evidence

inter-

from a c u r r e n t

group of t h e o r e t i c i a n s

interaction

quite different 4

section

E , v'

neutrino.

300 GeV i n the c e n t e r o f

Thus the e x p l o r a t i o n of the c r o s s

as p - d e c a y .

transfer.

to l o w e s t o r d e r p r e d i c t s

Such a f o r m u l a v i o l a t e s

"diagonal"

rather

to be

+ e" - v

region is

to

near the l i m i t o f zero momentum

section

e

limits

and o n l y e x p l o r e s

The second p r o c e s s observed.

neutrinos.3

of the

constant

couplings

such

places:

.1G < G d < 2G, -5 where G = 10

2 /m

and G^ i s

the d i a g o n a l

coupling.

The lower l i m i t comes from a s t r o p h y s i c a l5 arguments concerning

the r a t e of s t e l l a r

important e n e r g y - r e l e a s e emission,

e~

cooling.

process

e" + v g + v g .

is

neutrino-pair

The upper l i m i t

by an e x p e r i m e n t of R e i n e s and G u r r . ^ 34

Here the

They

is

set

observe

the

process v g

Savannah

+ e" -»• v g

+ e" u s i n g

River reactor.

signal, and a very apparatus

careful

is r e q u i r e d

It m a y

using v g

Los A l a m o s

Meson

able experiment Double

would

Facility

detect ^

beta decay

difficulties

are e x t e r n a l .

The

Te130

does

upper

produced

limit.

by A

the

reason-

events/day.'' second-order

not s u f f e r

because

the

(LAMPF).

is a g e n u i n e

Its c a l c u l a t i o n

divergence

5

any

neutrino-electron

stopped y +

Physics

of

a meaningful

to o b s e r v e

from

the

do n o t o b s e r v e

understanding

to g i v e

be f e a s i b l e

scattering

process.

They

from

all

the

weak

from

particles

decay

. Xe130

+

e"

+

e" + v

e

v . e

+

o has

been observed

of the m e t h o d isotopes

is to s t u d y

normal

for

done

samples

isotopes.

abundances.

With

by s t u d y

o u t o f the s a m p l e .

o f the The

is t h a t

Xe

1 30

is

xenon

half-

years.

of the of the

is in g o o d

the t h e o r e t i c a l

calculation,

This

somewhat more

interest.

r e s u l t has

t^

2

than

I n s t e a d of g o i n g by p r o c e s s 35

of

expected

This

ore Xe

1 30

agreement 22 5±2

with

the

strong

The

11? £

dating

diffusion

result

of

1 shows

of the d e c a y .

radioactive

essence

the e x c e p t i o n

Pi 34+0 to be t = i o £ 1 • •

by c a r e f u l and

The

Figure

The excess

the e x i s t e n c e

life w a s e v a l u a t e d was

ores.

of Xe 1 30 , the d i s t r i b u t i o n

the e x c e s s

evidence

of the

means.

the d i s t r i b u t i o n

in t e l l u r i u m - r i c h

distribution

for

by g e o l o g i c a l

= 10 cultural a), a

5 ^ .

neutrinoless

double

b) if t h e r e w e r e the s e c o n d final

spectrum. vertices 10

16

conclude

of the the

From 9

that

lepton

amplitude

and d o e s

same

conserving of l e p t o n

involve

key p o i n t s

of the

The w e a k various J The

first

which were

the

b),

electron

if the

be t ^

it is

two

=

2

can

process

is - 10

The

b)

upper

limit

non-conservation from _ p 10 is ^ 6 x l 0 ~

further

the

weak

useful

i

on

high-

.

interactions to w r i t e

down

the

theory.^

current

Jy

can

be d e c o m p o s e d

into

parts

= £ ,

qv)U

+

V 5

are

Let

2 m o y v 3gv )U = < B ' 1IV

^

f^

) U

li V 5

|

The

the

the

| | .

G

|l + >|

By the CPT

theorem =

But the d e c a y

rate

|| .

for E" is f o u n d

from

the

matrix

element |

e Ol sai CL X

o +1 LO VO o

1 1 1

o o CM

LO co 1—

o O) (O o •1— -C

z o: LU o

53

CTI • O

O XI -O •1— -O ia o

TABLE Recent AQ/AS

III Experiments

K -»• irev

Group

Events

Method

CalTech

( 0 < T

s

< 8 )

1079

SC, C -

K°A° 142

H BC,

K + p + K°pti

(prlm)

Padua

Freon BC Spi r a l i z a t i on

312

Illinois Northeastern CERN ORSAY Vienna

ioniz

(prlm)

K + n -»• K°p SC,

shower

TT"C -

400

A°K° 5800

Wire SC, C iK/ + p + K i/O p i +

P r e s e n t World Avg.

Im x

-0.069

0.108

+0.09 -0.07

±0.036

CERN SACLAY OSLO

Wi scons i n

Re x

(prim)

0.06

0.10

±0.10

+0.12 -0.10

0.11

0.04

±0.07

±0.09

-0.13

-0.04

±0.11

±0.16

0.05 +0.025 -0.035

-0.01 ±0.02

Re x = + 0 . 0 2 1 ± 0 . 0 2 2 Im x = + 0 . 0 0 3 ± 0 . 0 2 0 Re x 1 = 0 . 0 9 ± 0 .10 Im x '

54

= 0.01±0 .1 5

f K

iryv

TABLE Check Ratio

Y

of

IA11

IV

= 1/2

Rule

for

K -»• 3tt

of R e d u c e d Rates

ooo/f(Y+-o)

0.9910.04

Y++./4(Y+00)

0 . 99±0.04

Y+.0/2^+oo)

0 . 8 4 ± 0 .04

Y /(Y,, '000 ++-

0 . 83±0.03

- Y,„„) '+00

55

|AI| *

I A11

*

5/2

3/2

FIGURE 1.

Relative

abundances

rium ore. natural

The

CAPTIONS of Xenon

horizontal

abundances

isotopes

bars

in

indicate

o f the X e n o n

Telluthe

isotopes

in

the

1 30 atmosphere. 2.

a)

Decay

Note

scheme

b) S p e c t r u m

for 0 ^

arrow

ing

decay.

marking

c) D i f f e r e n c e

in r e g i o n of 1 2 8 0

MeV.

4.

Survey

of q u a n t i t y

nuclei

pairs

releases.

Ratio

of

as

Line

through

ir+ir°ir0 (x , + ) and K" -> ir"ir°T70 ( x ' " ) . 7

of They

(a + - a~)/(a + + a") = 0.009±0.006, and ( r ( x , + ) r(x'"))/(r(x,+)

+ r(x'"))

r a t e comparison i s

= 0.0017±0.0020.

r(x+1)

= r(x')

TT±ir°Y.

that

that the rates r ( x + ) +

+ r(x'").

The same group has a l s o compared the K1

-

The x'

three times as s e n s i t i v e as

f o r x because CPT r e q u i r e s

find

To see a d i f f e r e n c e , 82

one must

rates establish

that

in a d d i t i o n

mode

there

to

t h e n AI direct

1 = 1 .

= 1/2 term

and

find

tt"tt°y) )/sum under

be

unable With

by

bremstrahlung

a direct

hadronic

of

phase

data

and

transition

one m i g h t

is

If t h e r e

is a

with

inner

expect from

the

differences

the

Rutherford

to e s t a b l i s h

the

existence

a total

700

events,

of

Kycia

radiation

in a p - s t a t e

be e n h a n c e d .

= 0.06±0.05.

analysis

to

Preliminary

asymmetry

inner Such

it is o u t

term.

an

The

amplitude,

as y e t

of a d i r e c t they

if

rates.

are

term.

and might

bremstrahlung

group

normal

the t ^ t t 0

allow

have

in d e c a y

the

is a d i r e c t

term w o u l d hence

to

of ^

tt + tt°y)

(r(K+ A

and

similar his

-

r(K~

experiment

collaborators

is at

Brookhaven. One of

time

moment both

of

reversal of

time

value

the m o s t

of

the

is the

This

and

space

quantity

tests

search

neutron.

reversal this

sensitive

for

for

violation

an e l e c t r i c

requires

a violation

reflection.

expected

dipole

A

if t h e r e

of

typical

were

a C - 21 8

violation

in e l e c t r o m a g n e t i c

The

of

value

< 5xl0~23 The

search

a measurement

on,

electric

e-cm with

interactions

inverse

the

for

has of

reaction,

indicated

90%

dipole

moment

of C in

extensive.

is

10

now

compared

photo-disintegration failure 83

electromagnetic

A few y e a r s

n + p -*• d + y, w h e n

a possible

is ^

confidence.9

violation

been

transitions

of

the

of detailed

ago to

the

deuterbalance.^®

Recently greatly

two e x p e r i m e n t s improved

184"

The

identified gamma

chamber.

The

plotted

pal

background

are

They

detected for

in 4 e n e r g y

2 constraints

of

fit for

beam

flight. spark

distributions

in F i g . 4.

The

is n + p +

70 t i m e s

at

deuterons

in a m u l t i p l a t e

bins

to the

The

the a n g u l a r

section

out

a neutron

time

in the e x p e r i m e n t

has a c r o s s

carried

used

and

with

f i r s t , by a

spectrum.

by m o m e n t u m

results

are

which

energy

rays w e r e

The

g r o u p , was

Cyclotron.^

with a continuous were

been completed

statistics.

Berkeley-Michigan-UCLA the L R L

have

larger.

princid + ir° , There

the d e s i r e d

reac-

tion. One

can

see f r o m

agreement with

the e x t e n s i v e l y

reaction.

There

experiment

so o n l y

pared.

In this

figure

of B a r t l e t t

in the

region

shapes

et a l . ^

Bartlett

are

the

neutron

are

the com-

the

disagreement

energy. be

in

This

expected

of the A { 1 2 3 8 )

resonance

state.

a n d his

experiment with

circles

an e f f e c t m i g h t

of the f o r m a t i o n intermediate

MeV

normalization

showing

dis-

inverse

of the c u r v e s

the o p e n

of 5 0 0 - 6 0 0

is the r e g i o n w h e r e

in the

the

is no

measured

is no a b s o l u t e

points

because

Fig. 4 that there

colleagues

improved

have

statistics

repeated

and

a

their

simple

1 2 apparatus. last

This

to be c a r r i e d

experiment was,sadly, o u t at the P P A .

84

one of

Deuterons

the

were

a c c e l e r a t e d i n the machine and s t r i p p e d on an nal

target.

target. ^ 5%.

The a p p a r a t u s was p l a c e d 2 4 0 '

The n a t u r a l

inter-

from the

energy s p r e a d of t h i s

beam was

Momentum measurement of an i n c i d e n t

neutron

c o u l d be made to a p r e c i s i o n b e t t e r than \% by use of the i n t e r n a l The a p p a r a t u s used f o r

bunching of the beam i n the PPA.

is

shown i n F i g .

5.

No magnet was

the d e u t e r o n arm, which s i m p l i f i e d

e t r y and a n a l y s i s .

the geom-

About 10% of the e v e n t s were

n + p - > - n + p + TT° , but these f a i l e d the

kinematic

tests.

conversion

The y - r a y s were d e t e c t e d by t h e i r

i n a t h i n lead s h e e t f o l l o w e d by w i r e s p a r k

chambers.

The d e u t e r o n s were a l s o d e t e c t e d by w i r e s p a r k

cham-

bers and t h e i r momentum determined by time of

flight.

The e n t i r e experiment ran o n - l i n e w i t h the PDP-10 computer. straints

The n + p in t h i s

d + y events

had t h r e e

con-

experiment.

F i g . 6 shows t h e i r

results.

Again there i s

e v i d e n c e f o r any d i s a g r e e m e n t w i t h the i n v e r s e tion, and hence no e v i d e n c e at a l l time-reversal

no

reac-

for a f a i l u r e

of

invariance.

At p r e s e n t , t h e r e i s o n l y one experiment shows some s l i g h t

evidence for a p o s s i b l e

which

failure

of d e t a i l e d b a l a n c e .

This occurred in a study

the r e a c t i o n ir~ + p

n + y c a r r i e d out by a group

from UCLA and B e r k e l e y at the 184"

cyclotron.13

The m o t i v a t i o n f o r the experiment was r e a l l y

85

to

of

study of

photoproduction

the

inverse

target

of

The

the c r o s s

time

reaction,

required

periment.

The

deuteron

one's

surprise,

shown

in F i g .

A(1238

MeV).

of y

n

The

+

because

recoil

proton

lack

tions.

of

lack

and

effect

errors

the and

they

w o r k will be m a d e

(p)

in t h e come

spectator.

spectator

for a f a i l u r e

before of

no

which

is

from

of

chamber. for

small is

between

It is

the

measurement

there

conthe

conceivable

correction lead

required

to

the d e u t e r i u m that at

do n o t f i n d a d i s c r e p a n c y .

be r e q u i r e d

to

severe

can

out

u~p

region

of d i s t i n c t i o n

pointed

the

and

Here

the g e n e r a l

be

assume

in a b u b b l e

are m o s t

in h a n d l i n g

It s h o u l d

energy

One m u s t

of t h e it".

production

of a v i s i b l e

dependent

+

ex-

analysis

to c o m p a r e

points

corrections

fusion

for

+ p

deuteron

the

is a d i s c r e p a n c y

solid

it

(p)

of

this

there

study

reaction.

7 f o r an e n e r g y

angles

that

is g r e a t

By

photoproduction

target made

inverse

the

the y d m e a s u r e m e n t s

The

deuteron

avoids

uncertain.

to u s e

with

one

the d i r e c t

temptation

measurements

+

for

section

reversal

in t h e y - n c h a n n e l .

anglecorrec-

higher Much

a convincing

more

case

time

reversal

in

Conference

in 1 9 6 8 ,

o n e of

can

this

reaction. At major W. L e e metry

the

topics

Vienna

of d i s c u s s i o n

and c o l l a b o r a t o r s in t h e D a l i t z

was

which

an e x p e r i m e n t

by

found

asym-

p l o t f o r n -»• tt + tt 86

the

a small tt° . ^

The

asymmetry was This

1.5±0.5%,

experiment

the P r i n c e t o n riment was number

greatly

was

time-of-f1ight

produced

decays were on e i t h e r

slightly

the

direction chamber

by the PPA

A much more

permitted

The

detection

the s c i n t i l l a t i o n This due were

very

loose

collected here

210 ,000 e v e n t s was

found.

lab

they

charged

chambers

placed

of

in s u c c e s s i v e

sparksupplied

geometrical pion

completed

eliminated

effi-

in o n e

the

of

the

suitable magnet

of a s i n g l e

counters

threshold

the e l i m i n a t i o n

increased

trigger

to d i f f e r e n c e

Reported

an

reaction

by a l t e r a t i o n

fields

the

target.

was

problem

of

near

The

spark

hydrogen

of c l e a r i n g

planes.

ciency.

by s o n i c

the experi-

In the

at r e s t .

expe-

apparatus.

in the

produced

at

larger

s o m e of

the

backwards.

improvements

the f x ? s p a r k - d r i f t

a

previous

neutrons

essentially

detected

The

by a m e a s u r e m e n t

T h e n' s w e r e

s i d e of the

Among

in the

Fig. 8 s h o w s

of f o r w a r d

and were moving

repeated

Not only was but also

error

produced

T7~ + p ->- n + n.

been

events.

Accelerator.^

collected,

eliminated.

T h e n signal

recently

improved.

of s y s t e m a t i c

ment were

were

has

Pennsylvania

of e v e n t s

sources

b a s e d on 4 0 , 0 0 0

of

trigger.

possible

bias

of TT+ a n d IT .

in i n t e r a c t i o n

Data

+ - o + on b o t h N ->• IT TT IT and N -»• TT IT Y . is the r e s u l t produced

Fig. 9 shows

for

N

-»•

TT+TT

IT0

by 730 M e V / c TT". the d i s t r i b u t i o n

87

with NO

effect

of

events

by s e x t a n t asymmetry Shown old

in the D a l i t z as a f u n c t i o n

for c o m p a r i s o n

in the D a l i t z quadrant

plot

are

is

asymmetries

is no e v i d e n c e magnetic

variable

points

from

of the l e f t - r i g h t

(0.03±0.2)%. are

system.

X. the

M o s t of t h e s e on the o r d e r

have

and

(+0.08±0.2)%

experiment

in the

of the o r d e r

there

electro-

seen.

point

violation

We now

turn

and are

actually

nomenological

for

conceivable

if s o , t h e y

too

new

are

The

field

measure

searches

parameters

experiments at

of 10

to

achieved. situation

psychological

is the g u a r a n t e e That

are d e f i n i t e

88

have

for CP or T

a factor

can be

something.

to

be r e l u c t a n t

to the e x p e r i m e n t a l

system.

small

delicate

We w o u l d

in a c a s e w h e r e

in this

K meson

searched

It is

do e x i s t ;

in s e n s i t i v i t y

neutral-K

of w o r k i n g

10

to e n c o u r a g e

increase

have

any

_3

something.

except

neutral

to 0 . 1 % .

A r o u n d of e v e n m o r e

uncover

ingenious

to u n c o v e r

the

experiments

effects

of e ^

failed

outside

of

r\j

might

asymmetry

sextant

of e f f o r t , m a n y

experiments

t h a t CP v i o l a t i o n

been

improved

for a C v i o l a t i o n

t r a c e of a CP v i o l a t i o n

effects

The

respectively

In t h i s

seven years

and precise

will

the d a t a

the

decay.

After

the

10 s h o w s

of the D a l i t z

value

and ( - 0 . 0 7 ± 0 . 2 ) % .

100

Fig.

experiment. The m e a s u r e d

this

plot.

for

advantage that

i s , the numbers

one phethat

c a n be m e a s u r e d .

The

finds

understanding

that little

measurements.

disappointment

It a p p e a r s

t i o n c a n be e x p r e s s e d parameter K and all

e, w h i c h

to g o o d a c c u r a c y

is a m e a s u r e

of the c o n t r i b u t i o n from

this

situation

produces

the

it has

by F i t c h

taken

there was

the f i r s t

between

Be r e g e n e r a t o r

of

fact,

seems

|AS|

to of

which = 2 CP-

is

consistent

different

ther,

interference

the

of

produced

the CP v i o l a t i n g

showed by a

KL

of the

decays. effect

particles were eliminated. was m a x i m a l l y

result expected

amplitude

in Be w a s e s s e n t i a l l y

if the

p h a s e of E w a s ^ 4 5 ° , the v a l u e theory.

89

regeneration

expected

and

if

on the

later

this

the basis

sug-

confirmed.

parameters

the a u d i e n c e

Fur-

constructive,

imaginary

Six y e a r s

has b e e n

The CP-violating assume

this

performed

The experiment

the

possibility

to

possibility

e x p e r i m e n t was

which was

of the s u p e r w e a k

its

K- 2ir° peak and (2) the v e r y small assigned monitor

to the d i f f r a c t i o n

correction

under

error

f o r the 3tt°

events.

G a i l l a r d and h i s c o l l a b o r a t o r s arg(n00)

and the magnitude

i s very s i m i l a r

have

| n 0 0 | .^^

remeasured

Their

to p r e v i o u s measurements

technique

that

they

19 20 have made. a ratio

'

The magnitude

|n 0 Q | i s e v a l u a t e d

to the copper r e g e n e r a t i o n a m p l i t u d e

f-f/k

They f i n d 58 e v e n t s above b a c k g r o u n d , as shown Fig.

17b.

This

l e a d s to the

K o l / ^ l ^

GeV =

where | f - f / k |

is expressed

are r e l u c t a n t

to quote a f i n a l

certainty

in

true that

|f-f/k|

but s e v e r a l

|f-f/k|

as g i v e n i n Table

in

O-13±.12)xl0-3,

in Fermis.

The a u t h o r s

v a l u e because of

i s dropping r a p i d l y

in t h i s

seem to agree r a t h e r

It

unis

region, well,

III.

An a v e r a g e of t h e s e v a l u e s g i v e s 96

.

result

i n the r e g i o n of 2 GeV.

measurements

as

2.6±0.1.

We

double may

the e r r o r

occur

to ± 0 . 2

because

over

the s p e c t r u m

then

find The

the

discussed

in d e t a i l

two-dimensional I n Q o |/< |

and

for

be a c h i e v e d .

likelihood

20.

is the o r t h o g o n a l i t y The

9(ri00)-

This

dependence

The

analysis

complicated

The Fig.

The

technique 18 s h o w s

is

the

for

important

of the p h a s e

result

since inco-

plot they obtain

> and a r g ( n 0 0 ) .

We

experiment.

of c o h e r e n t f r o m

in R e f .

the m a g n i t u d e .

ar

this

the time

is q u i t e

separation

cannot

which

rapidly-varying

a regenerator.

time d i s t r i b u t i o n

error

by the e x p e r i m e n t .

by o b s e r v i n g

following

herent events

is

has r e m e a s u r e d

is d o n e

the e x p e r i m e n t a l

note

observed

same group

of 2tt° d e c a y s of

the a m p l i t u d e

= (2.9+0.4)xl0"3

|n00|

measurement

to t a k e a c c o u n t

point

to

determination

is a r g ( n 0 Q )

=

38°±25°. 20

When

this

is c o m b i n e d

they

find a r g ( n Q 0 )

=

with

the p r e v i o u s

experiment,

43°±19°.

We h a v e c o m b i n e d all the e x p e r i m e n t s w h i c h m e a s u r e d | n 0 0 l in T a b l e IV. We g i v e the v a l u e s p |n00l take

.

the e x p e r i m e n t of D a r r i u l a t

|n + _| = ( 1 . 9 4 ± 0 . 0 3 ) x l 0 " 3 .

source also

For

of t h i s

number

recomputed

all

from m e a s u r e m e n t s the xlO6

following sec"1,32

0.007),33

(We will

in a l a t e r

the v a l u e s

of

J

of r ( K ^ ^ 2ir°)/r(K L

constants:

discuss We

the have

derived 3tt°)

using

all)

=

(19.40±0.16)

F ( k l - 3 T ° ) / r ( K l - all)

=

(0.215±

r ( K $ + all)

r(KL

et a l . , w e

paragraph.) o |n

have for

= (1.160+0.008)xl010

97

sec"1,33

r ( K s + 77 + TT")/r(K s + ^ V ) f o r the w e i g h t e d

average

has

been m u l t i p l i e d

ing

value

for

= (2.22±0.03),34 is v e r y

poor.

by S = V x 2 / D F

The

The

= 1.7.

X

2

error

The

result-

| is 2 . 0 8 ± 0 . 1 6 . O n e c a n see t h a t 2 a m a j o r c o n t r i b u t i o n to the x comes from a single experiment.

|n

If t h i s

experiment

is r e m o v e d

the

? average note

hardly

changes,

b u t the x

that any background

raise

the Using

v a l u e of the

data

are v e r y

which goes undetected

have

from

The

all)

L

the m e a s u r e d

= 0.785±0.00733

ir + ir")/r(K^ -»• a l l ) . t i o n are g i v e n good.

The

in T a b l e

to the

large

iryv and irev d e c a y s No new m e a s u r e m e n t A new m e a s u r e m e n t The mass

in

|n+

branching

for is

residual

background

has

Am

ratio

calcula-

systematic

subtraction

error of

experiments.

been made

=

r (Kj_ +

embarrassingly

since

of this q u a n t i t y w o u l d

difference

the

| comes

this

in s o m e of the

of n + _

ratios

Here

in c o m p u t i n g

The x 2

T h e r e m a y be a small

in n + _ d u e

will

We use r (K^ -»• c h a r g e d )

input data V.

|ri + _|.

error

r ( K L ->- ir + iT~)/r(K L -»• c h a r g e d ) . /rU

and branching

re-evaluated

consistent.

almost entirely

We

|nQ0|.

same decay rates

c i t e d a b o v e , we

is i m p r o v e d .

be

welcome.

) - m(K^))

now b e e n m e a s u r e d by t h r e e g r o u p s to h i g h T h e s e v a l u e s are g i v e n in T a b l e V I . When

1966.

has

precision. these values 33

are c o m b i n e d

with

the

previous

f i n d s Am = ( 0 . 5 4 0 ± 0 . 0 0 3 5 ) x l 0 _ 1 0 riments

have d e m o n s t r a t e d

world average, sec-1.

Several

t h a t Am as d e f i n e d 98

one expe-

here

is

positive. of

49

This

value

leads

to a " n a t u r a l

phase"

42.9±0.3°. The

mits

precision mass-difference

increased

precision

a r g ( n + _) =