Determination of the parity of the neutral pion via its four-electron decay.
We present a new determination of the parity of the neutral pion via the double Dalitz decay pi0-->e+e-e+e-. Our sample, which consists of 30,511 candidate decays, was collected from KL-->pi0pi0pi0 decays in flight at the KTeV-E799 experiment at Fermi National Accelerator Laboratory. We confirm the negative pi0 parity and place a limit on scalar contributions to the pi0-->e+e-e+e- decay amplitude of less than 3.3% assuming CPT conservation. The pi0gamma*gamma* form factor is well described by a momentum-dependent model with a slope parameter fit to the final state phase-space distribution. Additionally, we have measured the branching ratio of this mode to be B(pi0-->e+e-e+e-)=(3.26+/-0.18)x10(-5).
Abouzaid
E
E
The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637, USA.
Arenton
M
M
Barker
A R
AR
Bellantoni
L
L
Blucher
E
E
Bock
G J
GJ
Cheu
E
E
Coleman
R
R
Corcoran
M D
MD
Cox
B
B
Erwin
A R
AR
Escobar
C O
CO
Glazov
A
A
Golossanov
A
A
Gomes
R A
RA
Gouffon
P
P
Hsiung
Y B
YB
Jensen
D A
DA
Kessler
R
R
Kotera
K
K
Ledovskoy
A
A
McBride
P L
PL
Monnier
E
E
Nguyen
H
H
Niclasen
R
R
Phillips
D G
DG
Ramberg
E J
EJ
Ray
R E
RE
Ronquest
M
M
Santos
E
E
Slater
W
W
Smith
D
D
Solomey
N
N
Swallow
E C
EC
Toale
P A
PA
Tschirhart
R
R
Wah
Y W
YW
Wang
J
J
White
H B
HB
Whitmore
J
J
Wilking
M J
MJ
Winstein
B
B
Winston
R
R
Worcester
E T
ET
Yamanaka
T
T
Zimmerman
E D
ED
Zukanovich
R F
RF