Measurements of the mass, total width, and two-photon partial width of the eta(c) meson.
Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.
Brandenburg
G
G
Harvard University, Cambridge, Massachusetts 02138, USA.
Ershov
A
A
Gao
Y S
YS
Kim
D Y
DY
Wilson
R
R
Browder
T E
TE
Li
Y
Y
Rodriguez
J L
JL
Yamamoto
H
H
Bergfeld
T
T
Eisenstein
B I
BI
Ernst
J
J
Gladding
G E
GE
Gollin
G D
GD
Hans
R M
RM
Johnson
E
E
Karliner
I
I
Marsh
M A
MA
Palmer
M
M
Plager
C
C
Sedlack
C
C
Selen
M
M
Thaler
J J
JJ
Williams
J
J
Edwards
K W
KW
Janicek
R
R
Patel
P M
PM
Sadoff
A J
AJ
Ammar
R
R
Bean
A
A
Besson
D
D
Davis
R
R
Kwak
N
N
Zhao
X
X
Anderson
S
S
Frolov
V V
VV
Kubota
Y
Y
Lee
S J
SJ
Mahapatra
R
R
O'Neill
J J
JJ
Poling
R
R
Riehle
T
T
Smith
A
A
Stepaniak
C J
CJ
Urheim
J
J
Ahmed
S
S
Alam
M S
MS
Athar
S B
SB
Jian
L
L
Ling
L
L
Saleem
M
M
Timm
S
S
Wappler
F
F
Anastassov
A
A
Duboscq
J E
JE
Eckhart
E
E
Gan
K K
KK
Gwon
C
C
Hart
T
T
Honscheid
K
K
Hufnagel
D
D
Kagan
H
H
Kass
R
R
Pedlar
T K
TK
Schwarthoff
H
H
Thayer
J B
JB
von Toerne
E
E
Zoeller
M M
MM
Richichi
S J
SJ
Severini
H
H
Skubic
P
P
Undrus
A
A
Chen
S
S
Fast
J
J
Hinson
J W
JW
Lee
J
J
Miller
D H
DH
Shibata
E I
EI
Shipsey
I P
IP
Pavlunin
V
V
Cronin-Hennessy
D
D
Lyon
A L
AL
Thorndike
E H
EH
Jessop
C P
CP
Marsiske
H
H
Perl
M L
ML
Savinov
V
V
Ugolini
D
D
Zhou
X
X
Coan
T E
TE
Fadeyev
V
V
Maravin
Y
Y
Narsky
I
I
Stroynowski
R
R
Ye
J
J
Wlodek
T
T
Artuso
M
M
Ayad
R
R
Boulahouache
C
C
Bukin
K
K
Dambasuren
E
E
Karamov
S
S
Majumder
G
G
Moneti
G C
GC
Mountain
R
R
Schuh
S
S
Skwarnicki
T
T
Stone
S
S
Viehhauser
G
G
Wang
J C
JC
Wolf
A
A
Wu
J
J
Kopp
S
S
Mahmood
A H
AH
Csorna
S E
SE
Danko
I
I
McLean
K W
KW
Márka
S
S
Xu
Z
Z
Godang
R
R
Kinoshita
K
K
Lai
I C
IC
Schrenk
S
S
Bonvicini
G
G
Cinabro
D
D
McGee
S
S
Perera
L P
LP
Zhou
G J
GJ
Lipeles
E
E
Pappas
S P
SP
Schmidtler
M
M
Shapiro
A
A
Sun
W M
WM
Weinstein
A J
AJ
Würthwein
F
F
Jaffe
D E
DE
Masek
G
G
Paar
H P
HP
Potter
E M
EM
Prell
S
S
Sharma
V
V
Asner
D M
DM
Eppich
A
A
Hill
T S
TS
Morrison
R J
RJ
Briere
R A
RA
Ferguson
T
T
Vogel
H
H
Behrens
B H
BH
Ford
W T
WT
Gritsan
A
A
Roy
J
J
Smith
J G
JG
Alexander
J P
JP
Baker
R
R
Bebek
C
C
Berger
B E
BE
Berkelman
K
K
Blanc
F
F
Boisvert
V
V
Cassel
D G
DG
Dickson
M
M
Drell
P S
PS
Ecklund
K M
KM
Ehrlich
R
R
Foland
A D
AD
Gaidarev
P
P
Galik
R S
RS
Gibbons
L
L
Gittelman
B
B
Gray
S W
SW
Hartill
D L
DL
Heltsley
B K
BK
Hopman
P I
PI
Jones
C D
CD
Kreinick
D L
DL
Lohner
M
M
Magerkurth
A
A
Meyer
T O
TO
Mistry
N B
NB
Nordberg
E
E
Patterson
J R
JR
Peterson
D
D
Riley
D
D
Thayer
J G
JG
Thies
P G
PG
Urner
D
D
Valant-Spaight
B
B
Warburton
A
A
Avery
P
P
Prescott
C
C
Rubiera
A I
AI
Yelton
J
J
Zheng
J
J