Polarization measurements in high-energy deuteron photodisintegration.
We present measurements of the recoil proton polarization for the d(gamma-->,p-->)n reaction at straight theta(c.m.) = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p(y) vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(gamma,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.
Wijesooriya
K
K
Université Blaise Pascal/IN2P, Aubière, France.
Afanasev
A
A
Amarian
M
M
Aniol
K
K
Becher
S
S
Benslama
K
K
Bimbot
L
L
Bosted
P
P
Brash
E
E
Calarco
J
J
Chai
Z
Z
Chang
C C
CC
Chang
T
T
Chen
J P
JP
Choi
S
S
Chudakov
E
E
Churchwell
S
S
Crovelli
D
D
Dieterich
S
S
Dumalski
S
S
Dutta
D
D
Epstein
M
M
Fissum
K
K
Fox
B
B
Frullani
S
S
Gao
H
H
Gao
J
J
Garibaldi
F
F
Gayou
O
O
Gilman
R
R
Glamazdin
S
S
Glashausser
C
C
Gomez
J
J
Gorbenko
V
V
Hansen
O
O
Holt
R J
RJ
Hovdebo
J
J
Huber
G M
GM
de Jager
C W
CW
Jiang
X
X
Jones
C
C
Jones
M K
MK
Kelly
J
J
Kinney
E
E
Kooijman
E
E
Kumbartzki
G
G
Kuss
M
M
LeRose
J
J
Liang
M
M
Lindgren
R
R
Liyanage
N
N
Malov
S
S
Margaziotis
D J
DJ
Markowitz
P
P
McCormick
K
K
Meekins
D
D
Meziani
Z E
ZE
Michaels
R
R
Mitchell
J
J
Morand
L
L
Perdrisat
C F
CF
Pomatsalyuk
R
R
Punjabi
V
V
Ransome
R D
RD
Roche
R
R
Rvachev
M
M
Saha
A
A
Sarty
A
A
Schulte
E C
EC
Simon
D
D
Strauch
S
S
Suleiman
R
R
Todor
L
L
Ulmer
P E
PE
Urciuoli
G M
GM
Wojtsekhowski
B
B
Xiong
F
F
Xu
W
W