Measurements of parity violation in neutron-nucleus reactions

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:6388046

Seestrom, S J; Bowman, C D; Bowman, J D; Knudson, J; Mortensen, R; Penttila, S; Szymanski, J J; Wender, S A; Yoo, S H; Yuan, V W ^[1]; Frankle, C M; Gould, C R; Haase, D G; Mitchell, G E ^[2]; Roberson, N R; Zhu, X ^[3]

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1. Los Alamos National Lab., NM (United States)
2. North Carolina State Univ., Raleigh, NC (United States) Triangle Universities Nuclear Lab., Durham, NC (United States)
3. Duke Univ., Durham, NC

In this talk I describe a new generation of experiments studying the weak interaction between nucleons. Measurements of the effect of this interaction are few in number and the significance of the observed effects are generally small. It is well known that the weak interaction violates parity. This was first experimentally established by C. S. Wu through measurement of an asymmetry of electrons emitted in the beta-decay of polarized {sup 60}Co. The measured asymmetry was large because beta decay is a weak interaction process. For a process in which the strong interaction can contribute, we expect much smaller asymmetries, of order 10{sup {minus}7}. In the work I will describe here we study the effects of the weak interaction through the signal of the parity violation associated with that interaction. There are two basic classes of experiment used to detect parity violation. The first relies on the measurement of a cross section or width that would vanish if parity were conserved. One example of this type of experiment in nuclear physics is the decay of an unnatural parity state to a 0+ nucleus and an {alpha}-particle. Such measurements have been made for two nuclei: {sup 16}O(2{sup {minus}}) {implies} {sup 12} C(g.s) + {alpha} and {sup 20}N{var epsilon}(1{sup +}) {implies} {sup 16} O(g.s) + {alpha}. Parity-violating widths as small as of 10{sup {minus}10} eV have been measured in these experiments. The second class of experiments involves a measurement of pseudo-scalar observables which are odd under parity inversion. These involve correlations between spin and linear angular momenta, for example circular polarization of {gamma}-rays ({sigma}{sub {gamma}} {center dot} {kappa}{sub {gamma}}) or longitudinal analyzing power ({sigma}{sub p} {center dot} {kappa}{sub p}). 20 refs., 6 figs.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6388046
• Report Number(s): LA-UR-91-3321; CONF-9105106-31; ON: DE92002470; TRN: 91-033263
• Resource Relation: Conference: Conference on the intersections between particle and nuclear physics, Tucson, AZ (United States), 23-29 May 1991
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COMPOUND NUCLEI
PARITY
NUCLEONS
WEAK INTERACTIONS
CROSS SECTIONS
HELICITY
LANTHANUM 139
NEUTRON BEAMS
P WAVES
PSEUDOSCALARS
S WAVES
THORIUM 232
TIN 117
URANIUM 238
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYONS
BASIC INTERACTIONS
BEAMS
DAYS LIVING RADIOISOTOPES
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FERMIONS
HADRONS
HEAVY NUCLEI
INTERACTIONS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LANTHANUM ISOTOPES
NUCLEI
NUCLEON BEAMS
ODD-EVEN NUCLEI
PARTIAL WAVES
PARTICLE BEAMS
PARTICLE PROPERTIES
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SPONTANEOUS FISSION RADIOISOTOPES
STABLE ISOTOPES
THORIUM ISOTOPES
TIN ISOTOPES
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES
662120* - General Theory of Particles & Fields- Symmetry
Conservation Laws
Currents & Their Properties- (1992-)
663560 - Nuclear Mass Ranges- A=90-149- (1992-)