Parity Violation in the Compound Nucleus

transcript

G. E. Mitchell

North Carolina State University

SYMMETRY BREAKING, RMT AND NUCLEI

• USE NUCLEUS AS TEST LABORATORY FOR RMT PREDICTIONS

• ASSUME RMT TO INTERPRET NUCLEAR PHENOMENA

• ISOSPIN SYMMETRY BREAKING

EFFECT ON LEVEL STATISTICS

EFFECT ON TRANSITIONS • PARITY VIOLATION

ENHANCEMENT IN COMPOUND NUCLEUS

FOLLOWINGWU-AMBLER, GARWIN-LEDERMAN

MANY STUDIES OF PARITY VIOLATION IN STRONG INTERACTION PROCESSES

CONFLICTING RESULTS (MAINLY RUSSIAN) IN NEUTRON-INDUCED REACTIONS LOOKING AT GAMMA RAYS

FINNALY AT ILL VERY LARGE NEUTRON SPIN ROTATION

CONFUSIONEXTREME EXAMPLE

RESORT TO FIFTH FORCEEXPLANATION

SUSHKOV-FLAMBAUM

OBSERVATION OF LARGE PARITY VIOLATION IN NEUTRON RESONANCES IN 139LA FRANK LABORATORY, DUBNA

THEN WE STARTED TRIPLE COLLABORATION

p-wave level s-wave levels many levels contribute PNC asymmetry)

x neutron decay amplitude

Ex resonance energies

V matrix element of PNC interaction between levels and

)/() 2/1

One measured variable p

many matrix elements V

A known

Assume V independent Gaussian

Random variables with mean zero and variance Mj2

Mj2 is the weak interaction mean squared matrix element

p is sum of variables V with constant coefficients

Therefore p is Gaussian random variable with variance Mj

Determine Mj2 from experimental data

SIGN CORRELATIONEXPLANATIONS

AUERBACHDESPLANQUES

FLAMBAUMHAYES

KERMANKOONIN

WEIDENMUELLERET AL.

NO SUCH EFFECT IN ALL OTHER MEASUREMENTS FOR 15 NUCLEI

EXTENDED MEASUREMENTS TO HIGHER ENERGIES

OBSERVED OPPOSITE SIGN FOR PV

BEST GUESS

LOCAL DOORWAY

CONSISTENT WITH KERMAN’S VIEW

GENERAL OVERVIEW

G.E.MITCHELL AND H.A. WEIDENMUELLER

REV.MOD.PHYS. 71,445 (1999)

ALL THE DETAILSG.E.MITCHELL, J.D.BOWMAN,

S.I.PENTTILA, E.I.SHARAPOVPHYS. REPORTS 354, 157 (2001)

Parity Violation in the Compound Nucleus

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