REACTOR BASED FUNDAMENTAL PHYSICS

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REACTOR BASED FUNDAMENTAL PHYSICS

N. Ramsey

To cite this version:

N. Ramsey. REACTOR BASED FUNDAMENTAL PHYSICS. Journal de Physique Colloques, 1984,

45 (C3), pp.C3-285-C3-289. �10.1051/jphyscol:1984347�. �jpa-00224065�

REACTOR BASED FUNDAMENTAL PHYSICS

N.F. Rarnsey

U n i v e r s i t y of V i r g i n i a , C h a r l o t t e s v i l l e , VA 22901, U.S.A and Harvard University, Cambridge, Massachusetts 02138, U.S.A.

R6sum6 - Un Sommaire De La Confgrence "Reactor Based Fundamental Physics"

A b s t r a c t - Summary o f t h e Conference on Reactor Based Fundamental Physics.

INTRODUCTION

The u l t i m a t e standard f o r a summary speaker was e s t a b l i s h e d by one o f my f r i e n d s many years ago. A new s u b - f i e l d of physics seemed t o be emerging so an i n t e r n a -

t i o n a l conference was c a l l e d and my f r i e d was asked t o g i v e t h e summary t a l k . A l l seemed t o be going w e l l a t t h e conference h i 1 he gave h i s summary t a l k . I n t h e summary t a l k he pointed o u t - q u i t e v a l i d l y - t h a t approximately o n e - t h i r d o f t h e conference papers were merely r e f o r m u l a t i o n s of p r e v i o u s l y w e l l known r e s u l t s , another t h i r d were t r i v i a l and t h e remaining papers were t o t a l l y wrong. Not o n l y d i d t h e summary t a l k so d e s t r o y t h e conference t h a t no proceedings were published b u t i t even a n n i h i l a t e d t h e new s u b - f i e l d , which has never emerged again.

By t h a t h i g h standard my present summary w i l l be a f a i l u r e . I am happy t o r e p o r t t h a t t h e f i e l d o f Reactor Based Fundamental Physics i s t h r i v i n g and i t w i l l c o n t i n u e t o t h r i v e f o l l o w i n g my summary.

A f t e r I r e a l i z e d , I c o u l d n o t destroy t h e s u b j e c t i t s e l f , I thought o f a way i n which I might a t l e a s t prove t h a t t h e conference i t s e l f was useless and merely con- t r i b u t e d much t a l k f o l l o w e d by no a c t i o n . Since t h e r e was a conference s i x years ago on t h e same subject, t h i s hypothesis i s s u b j e c t t o experimental t e s t . Geoffrey Green Greene, Blayne Heckel and I t h e r e f o r e analyzed t h e papers presented a t t h e e a r l i e r conference t o determine t h e number o f t o p i c s f o r which t h e r e has been sub- s t a n t i a l progress s i n c e t h e l a s t meeting, t h e number w i t h questionable progress and t h e number w i t h no s i g n i f i c a n t progress. I am pleased t o r e p o r t t h a t o f 20 t o p i c s , t h e r e has been s u b s t a n t i a l progress i n 16, questionable progress i n 2 and no progress i n 2 . W i t h s u c h a g o o d r e c o r d i t i s c l e a r t h a t n o t o n l y i s t h e f i e l d t h r i v i n g b u t a l s o t h e meetings are s e r v i n g a v a l u a b l e f u n c t i o n . I am sure t h a t a l l who have been here d u r i n g t h e past t h r e e days have independently reached t h e same conclusion w i t h o u t t h e n e c e s s i t y o f a q u a n t i t a t i v e t e s t .

I n advance o f t h i s meeting, I planned i n my summary t a l k t o concentrate our a t t e n - t i o n by focussing on t h e f o u r o r f i v e most s i g n i f i c a n t r e p o r t s and t o omit e n t i r e l y t h e t o p i c s which were unimportant o r u n i n t e r e s t i n g . However, now t h a t t h e r e p o r t s have been presented I f i n d t h a t t h e Conference Committee has a l r e a d y done t h i s e l i m i n a t i o n f o r me and t h a t almost a l l o f t h e t o p i c s on t h e program were both i n t e r e s t i n g and fundamental. I t h e r e f o r e decided l a s t n i g h t t o f o l l o w e x a c t l y t h e o p p o s i t e procedure and t o discuss a l l o f t h e r e p o r t s b r i e f l y b u t t o do so i n an o u t l i n e form which emphasizes the coherenet u n i t y of t h e whole f i e l d . I n t h e o u t l i n e I w i l l g i v e some o f t h e p r i n c i p a l r e s u l t s , b u t t o preserve t h e o u t l i n e form

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984347

C3-286 JOURNAL DE PHYSIQUE

I s h a l l n o t r e p o r t t h e explanations given i n t h e t a l k s and t o a v o i d l o s i n g t h e physics i n a l i s t o f names I s h a l l g i v e i n parentheses o n l y t h e l a s t name o f t h e person who presented t h e r e p o r t . An equation g i v i n g a c u r r e n t r e s u l t b u t f o l l o w e d by an arrow p o i n t i n g t o a d i f f e r e n t number i n d i c a t e s t h e progress t h a t i s expected i n f u t u r e experiments.

I . NEUTRON PROPERTIES AND SYPIMETRI ES (a) E l e c t r i c Charge

(b) E l e c t r i c D i p o l e Moment

d = (-2.0 n + 1 .O) x e cin (Serebrov)

= (+0.3 +4.8) XIO-'~ e cm (Morse)

Proposed experiment i n 1 iq u i d 4 ~ e (Golub)

Proposed Los Alamos experiment w i t h pulsed neutrons (Ringo)

Importance t o cosmological t h e o r i e s t h a t a t t r i b u t e p r o t o n - a n t i p r o t o n asymmetry t o CP v i o l a t i o n s h o r t l y a f t e r t h e b i g bang.

( c ) Decay

1 . Mean l i f e .rn = 9 1 8 t 1 4 , 8 7 7 c 8 o r 9 3 7 2 1 8 (Byrne) New experiment (Liaud)

Importance o f Tn i n t h e He p r o d u c t i o n i n t h e u n i v e r s e and i n t h e 4 cosmological 1 im i t t o t h e number o f quark-neutrino generations.

2. Angular d i s t r i b u t i o n

@-decay asymmetry

A = -gA/gV = 1.270 20,009 ( L a s t )

Experiment t o t e s t t i m e r e v e r s a l symmetry i n l e f t - r i g h t symmetric models (Bowl es)

( d ) E l e c t r i c P o l a r i z a b i l i t y

Re1 i a b l e measurements needed (Leeb)

(e) Parity-Non-Conserving ( PNC) Neutron-Nucl e i I n t e r a c t i o n s 1 . Theory

General theory (Desplanques) n-d t h e o r y ( ~ v i s h a i ' ) 2. F i s s i o n

PNC i n f i s s i o n . Experimentally confirmed and t h e o r e t i c a l l y

reasona b l e ( ~ e t r o v )

l17sn, Sn, Pb, La, Hope e v e n t u a l l y t o do l i g h t e r elements (Heckel) 4. Resonance cross sections

Br, Sn, La, Cd, Nb, Nd (Sharapov) 5. PNC i n n,y r e a c t i o n s

E f f e c t s p e r s i s t i n heavy n u c l e i even w i t h many y t s (Nazarenko)

New experiment (Avenier)

P = (1.8 1,8) x lo-' (Nazarenko) Y

( f ) Nucleon Decay

Review o f proton decay. A few candidate events, no evidence ( F i o r i n i ) No magnetic monopoles y e t seen

No bound n-ti o s c i l l a t i o n s seen ( g ) Free n-ii o s c i l l a t i o n s

T > l o 6 sec (90% c l ) ( ~ a l d o - k e o l i n and Prosper) n-ii

+

l o 8 sec

( a ) Prompt y-Ray Spectroscopy

C a l i b r a t i o n o f wave lengths, deuteron b i n d i n g energy, neutron mass and fundamental constant NAh/c. (Greene)

111. NEUTRINOS

(a) Neutrino O s c i l l a t i o n s 1 . Review

No evidence f o r o s c i i l a t i o n s . Extensive exclusion p l o t s o f e x p e r i - m e n t a l l y unacceptable values o f mass and m i x i n g angle. ( ~ o s s b a u e r ) 2. The data t a k i n g phase o f t h e Bugey experiment has been completed, t h e data a r e being analyzed and f i n a l r e s u l t s should soon be presented.

( Koang)

3. Reactor spectrum (Schreckenbach)

4. Search f o r massive n e u t r i n o s i n 6-decay (Schreckenbach) ( b ) Theory

1. Majorana n e u t r i n o s (Bernabeu)

2. Neutrino o s c i l l a t i o n and s t e l l a r c o l l a p s e (Bernabeu)

3. U n i f i e d t h e o r i e s and i n t e r n a l s t r u c t u r e o f l e p t o n s and quarks

( F r i t z s c h )

C3-288 JOURNAL DE PHYSIQUE

I V . WAVE PROPERTIES OF NEUTRINOS

( a ) Neutron I n t e r f e r o m e t e r y and I t s R e l a t i o n t o Fundamental Physics L o n g i t u d i n a l and transverse coherence s t u d i e s . Dynamic e f f e c t s . Phase echo. Time dependent wave packets and i n t e r a c t i o n s . A l l experiments agree w i t h quantum mechanics. (Rauch)

( b ) Symmetry V i o l a t i o n s i n Neutron I n t e r f e r o m e t r y

E f f e c t o f neutron s p i n and Schwinger s c a t t e r i n g i n neutron i n t e r f e r o m e t r y . Possible i n t e r f e r o m e t e r t e s t s o f t i m e r e v e r s a l symmetry and p a r i t

Enhancements by Larmor 1 ength equal Pendel losung 1 ength. ( Z e i l in&) ( c ) Generalized Aharanov-Bohm and Wheeler Delayed Choice Experiments ( Z e i l i n g e r )

(d) Determination o f himn

h/mn = 3.956093(65) x lo-' m2s-l. Expected improvements. (Weirauch) ( e ) Wave Functions i n P o l a r i z e d Neutron Beams

Some p o l a r i z a t i o n e f f e c t s a r e r e l a t e d t o an i n t e r p l a y between t h e s p a t i a l and s p i n wave f u n c t i o n s . (Mezei)

( f ) Quantum Mechanical E f f e c t s on Beam Chopping

E f f e c t on neutron wave f u n c t i o n o f passage o f beam through a s l i t w i t h t i m e dependent width. FOTOF. Mechanical time o f f l i g h t spectrometer.

(Gxhler)

( g ) Neutron Wave Pockets and L o n g i t u d i n a l Coherence

Coherence 1 ength n o t n e c e s s a r i l y equal t o packet 1 ength. D i f f r a c t i o n i n t i m e experiment. (Kl e i n )

(h) Wave 0pti:cs w i t h Cold Neutrons

Fresnel d i f f r a c t i o n zone p l a t e . V e r i f i c a t i o n o f quantum mechanics and e l i m i n a t i o n o f n o n - l i n e a r term i n Schrodinger equation t o ( K l e i n )

( i ) Neutron Fibres : A Possible A p p l i c a t i o n o f Neutron Optics. (Alvarez- ( Estrada )

( 3 ) Dynamical E f f e c t s i n Neutron O p t i c s and Spin I n t e r a c t i o n s .

Dynamical d i f f r a c t i o n t o use nuclear f i e l d s i n a c r y s t a l as a source of P and T v i o l a t i n g p o l a r i z a t i o n e f f e c t s . ( F o r t e )

( k ) Neutron Wave Optics w i t h U l t r a - C o l d Neutrons

G r a v i t a t i o n a l e f f e c t s , g r a v i t y focussing, g r a v i t y spectrometers, neutron microscope. ( S t e y e r l )

( k > New A p p l i c a t i o n s o f U l t r a Cold Neutron Physics i n Magnetic and

G r a v i t y F i e l d s .

Magnetic neutron d e c e l e r a t i o n w i t h a d i a b a t i c s p i n f l i p . ( ~ t s u r o )

All experiments f i t quantum mechanics remarkably w e l l .

V . FACILITIES

( a ) ILL F a c i l i t i e s f o r Fundamental Physics Experiments

Description o f present and f u t u r e ILL f a c i l i t i e s , (Ageron and Mampe) CONCLUSION

I t i s a p p r o p r i a t e t h a t we should end t h e conference with a d e s c r i p t i o n o f f a c i l i t i e s . All of us who do experiments i n fundamental r e a c t o r based physics a r e g r e a t l y depen- d e n t on t h e f a c i l i t i e s and t h o s e who provide and maintain them a t t h e ILL and el sewhere.

In conclusion, t h e r e f o r e , I should l i k e on behalf o f a l l of us t o express our deep

a p p r e c i a t i o n t o a l l t h o s e who help provide t h e s e valuable f a c i l i t i e s . In a d d i t i o n ,

we p a r t i c u l a r l y thank t h e ILL management and s t a f f f o r serving a s such e x c e l l e n t

hosts f o r t h i s s t i m u l a t i n g conference on Reactor Based Fundamental Physics.