Measurement of angular distributions of Drell-Yan dimuons in p+p interactions at 800 GeV/c.
We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a hydrogen target. The polar and azimuthal angular distribution parameters have been extracted over the kinematic range 4.5<m micromicro<15 GeV/c2 (excluding the Upsilon resonance region), 0<p T <4 GeV/c, and 0<x F<0.8. The p+p angular distributions are similar to those of p+d, and both data sets are compared with models which attribute the cos2varphi distribution either to the presence of the transverse-momentum-dependent Boer-Mulders structure function h1 perpendicular to 1 or to QCD effects. The data indicate the need to include QCD effects before reliable information on the Boer-Mulders function can be extracted. The validity of the Lam-Tung relation in p+p Drell-Yan data is also tested.
Zhu
L Y
LY
Hampton University, Hampton, Virginia 23187, USA.
Peng
J C
JC
Reimer
P E
PE
Awes
T C
TC
Brooks
M L
ML
Brown
C N
CN
Bush
J D
JD
Carey
T A
TA
Chang
T H
TH
Cooper
W E
WE
Gagliardi
C A
CA
Garvey
G T
GT
Geesaman
D F
DF
Hawker
E A
EA
He
X C
XC
Isenhower
L D
LD
Kaplan
D M
DM
Kaufman
S B
SB
Klinksiek
S A
SA
Koetke
D D
DD
Lee
D M
DM
Lee
W M
WM
Leitch
M J
MJ
Makins
N
N
McGaughey
P L
PL
Moss
J M
JM
Mueller
B A
BA
Nord
P M
PM
Papavassiliou
V
V
Park
B K
BK
Petitt
G
G
Sadler
M E
ME
Sondheim
W E
WE
Stankus
P W
PW
Thompson
T N
TN
Towell
R S
RS
Tribble
R E
RE
Vasiliev
M A
MA
Webb
J C
JC
Willis
J L
JL
Wise
D K
DK
Young
G R
GR