Formation of the $\eta_c$ in Two-Photon Collisions at LEP
M. Acciarri
,
P. Achard
,
O. Adriani
,
M. Aguilar-Benitez
,
J. Alcaraz
,
G. Alemanni
,
J. Allaby
,
A. Aloisio
,
M G. Alviggi
,
G. Ambrosi
,
H. Anderhub
,
V P. Andreev
,
T. Angelescu
,
F. Anselmo
,
A. Arefiev
,
T. Azemoon
,
T. Aziz
,
P. Bagnaia
,
L. Baksay
,
A. Balandras
(1)
,
R C. Ball
,
S. Banerjee
,
Sw. Banerjee
,
A. Barczyk
,
R. Barillere
,
L. Barone
,
P. Bartalini
,
M. Basile
,
R. Battiston
,
A. Bay
,
F. Becattini
,
U. Becker
,
F. Behner
,
J. Berdugo
,
P. Berges
,
B. Bertucci
,
B L. Betev
,
S. Bhattacharya
,
M. Biasini
,
A. Biland
,
J J. Blaising
(1)
,
S C. Blyth
,
G J. Bobbink
,
A. Boehm
,
L. Boldizsar
,
B. Borgia
,
D. Bourilkov
,
M. Bourquin
,
S. Braccini
,
J G. Branson
,
V. Brigljevic
,
F. Brochu
(1)
,
A. Buffini
,
A. Buijs
,
J D. Burger
,
W J. Burger
,
J. Busenitz
,
A. Button
,
X D. Cai
,
M. Campanelli
,
M. Capell
,
G. Cara Romeo
,
G. Carlino
,
a M. Cartacci
,
J. Casaus
,
G. Castellini
,
F. Cavallari
,
N. Cavallo
,
C. Cecchi
,
M. Cerrada
,
F. Cesaroni
,
M. Chamizo
,
y H. Chang
,
U K. Chaturvedi
,
M. Chemarin
(2)
,
A. Chen
,
G. Chen
,
G M. Chen
,
H F. Chen
,
H S. Chen
,
X. Chereau
(1)
,
G. Chiefari
,
L. Cifarelli
,
F. Cindolo
,
C. Civinini
,
I. Clare
,
R. Clare
,
G. Coignet
(1)
,
a P. Colijn
,
N. Colino
,
S. Costantini
,
F. Cotorobai
,
B. Cozzoni
,
B. de La Cruz
,
A. Csilling
,
S. Cucciarelli
,
T S. Dai
,
J A. van Dalen
,
R. d'Alessandro
,
R. de Asmundis
,
P. Deglon
,
A. Degre
(1)
,
K. Deiters
,
D. Della Volpe
,
P. Denes
,
F. de Notaristefani
,
A. de Salvo
,
M. Diemoz
,
D. van Dierendonck
,
F. Di Lodovico
,
C. Dionisi
,
M. Dittmar
,
A. Dominguez
,
A. Doria
,
M T. Dova
,
D. Duchesneau
(1)
,
D. Dufournaud
(1)
,
P. Duinker
,
I. Duran
,
H. El Mamouni
(3)
,
A. Engler
,
F J. Eppling
,
F C. Erne
,
P. Extermann
,
M. Fabre
,
R. Faccini
,
M A. Falagan
,
S. Falciano
,
A. Favara
,
J. Fay
(2)
,
O. Fedin
,
M. Felcini
,
T. Ferguson
,
F. Ferroni
,
H. Fesefeldt
,
E. Fiandrini
,
J H. Field
,
F. Filthaut
,
P H. Fisher
,
I. Fisk
,
G. Forconi
,
L. Fredj
,
K. Freudenreich
,
C. Furetta
,
Yu. Galaktionov
,
S N. Ganguli
,
P. Garcia-Abia
,
M. Gataullin
,
S S. Gau
,
S. Gentile
,
N. Gheordanescu
,
S. Giagu
,
Z F. Gong
,
G. Grenier
(2)
,
O. Grimm
,
M W. Gruenewald
,
R. van Gulik
,
V K. Gupta
,
A. Gurtu
,
L J. Gutay
,
D. Haas
,
A. Hasan
,
D. Hatzifotiadou
,
T. Hebbeker
,
A. Herve
,
P. Hidas
,
J. Hirschfelder
,
H. Hofer
,
G. Holzner
,
H. Hoorani
,
S R. Hou
,
I. Iashvili
,
B N. Jin
,
L W. Jones
,
P. de Jong
,
I. Josa-Mutuberria
,
R A. Khan
,
D. Kamrad
,
M. Kaur
,
M N. Kienzle-Focacci
,
D. Kim
,
D H. Kim
,
J K. Kim
,
S C. Kim
,
J. Kirkby
,
D. Kiss
,
W. Kittel
,
A. Klimentov
,
a C. Koenig
,
A. Kopp
,
I. Korolko
,
V. Koutsenko
,
M. Kraeber
,
R W. Kraemer
,
W. Krenz
,
A. Kunin
,
P. Lacentre
,
P. Ladron de Guevara
,
I. Laktineh
(2)
,
G. Landi
,
K. Lassila-Perini
,
P. Laurikainen
,
A. Lavorato
,
M. Lebeau
,
A. A. Lebedev
,
P. Lebrun
(2)
,
P. Lecomte
,
P. Lecoq
,
P. Le Coultre
,
H J. Lee
,
J M. Le Goff
,
R. Leiste
,
Emilio Leonardi
,
P. Levtchenko
,
C. Li
,
C H. Lin
,
W T. Lin
,
F L. Linde
,
L. Lista
,
Z A. Liu
,
W. Lohmann
,
E. Longo
,
y S. Lu
,
K. Luebelsmeyer
,
C. Luci
,
D. Luckey
,
L. Lugnier
(2)
,
L. Luminari
,
W. Lustermann
,
W G. Ma
,
M. Maity
,
L. Malgeri
,
A. Malinin
,
C. Mana
,
D. Mangeol
,
P. Marchesini
,
G. Marian
,
J.-P. Martin
(2)
,
F. Marzano
,
G G G. Massaro
,
K. Mazumdar
,
R R. Mcneil
,
S. Mele
,
L. Merola
,
M. Meschini
,
W J. Metzger
,
M. von Der Mey
,
D. Migani
,
A. Mihul
,
H. Milcent
,
G. Mirabelli
,
J. Mnich
,
G B. Mohanty
,
P. Molnar
,
B. Monteleoni
,
T. Moulik
,
G.-S. Muanza
(2)
,
F. Muheim
,
a J M. Muijs
,
M. Napolitano
,
F. Nessi-Tedaldi
,
H. Newman
,
T. Niessen
,
A. Nisati
,
H. Nowak
,
y D. Oh
,
G. Organtini
,
R. Ostonen
,
C. Palomares
,
D. Pandoulas
,
S. Paoletti
,
P. Paolucci
,
H K. Park
,
I H. Park
,
G. Pascale
,
G. Passaleva
,
S. Patricelli
,
T. Paul
,
M. Pauluzzi
,
C. Paus
,
F. Pauss
,
D. Peach
,
M. Pedace
,
y J. Pei
,
S. Pensotti
,
D. Perret-Gallix
(1)
,
B. Petersen
,
D. Piccolo
,
M. Pieri
,
P A. Piroue
,
E. Pistolesi
,
V. Plyaskin
,
M. Pohl
,
V. Pojidaev
,
H. Postema
,
J. Pothier
,
N. Produit
,
D O. Prokofiev
,
D. Prokofiev
,
J. Quartieri
,
G. Rahal-Callot
,
M A. Rahaman
,
N. Raja
,
R. Ramelli
,
P G. Rancoita
,
G. Raven
,
P. Razis
,
D. Ren
,
M. Rescigno
,
S. Reucroft
,
T. van Rhee
,
S. Riemann
,
K. Riles
,
A. Robohm
,
J. Rodin
,
B P. Roe
,
L. Romero
,
A. Rosca
,
S. Rosier-Lees
(1)
,
J A. Rubio
,
D. Ruschmeier
,
H. Rykaczewski
,
S. Sarkar
,
J. Salicio
,
E. Sanchez
,
M P. Sanders
,
M E. Sarakinos
,
C. Schaefer
,
V. Schegelsky
,
S. Schmidt-Kaerst
,
D. Schmitz
,
H. Schopper
,
D J. Schotanus
,
J. Schwenke
,
G. Schwering
,
C. Sciacca
,
D. Sciarrino
,
A. Seganti
,
L. Servoli
,
S. Shevchenko
,
N. Shivarov
,
V. Shoutko
,
E. Shumilov
,
A. Shvorob
,
T. Siedenburg
,
D. Son
,
B. B.N. Smith
,
P. Spillantini
,
M. Steuer
,
D P. Stickland
,
A. Stone
,
H. Stone
,
B. Stoyanov
,
A. Straessner
,
K. Sudhakar
,
G. Sultanov
,
L Z. Sun
,
H. Suter
,
J D. Swain
,
Z. Szillasi
,
X W. Tang
,
L. Tauscher
,
L. Taylor
,
C. Timmermans
,
S C C. Ting
,
S M. Ting
,
S C. Tonwar
,
J. Toth
,
C. Tully
,
K L. Tung
,
Y. Uchida
,
J. Ulbricht
,
E. Valente
,
G. Vesztergombi
,
I. Vetlitsky
,
D. Vicinanza
,
G. Viertel
,
S. Villa
,
M. Vivargent
(1)
,
S. Vlachos
,
I. Vodopianov
,
H. Vogel
,
H. Vogt
,
I. Vorobiev
,
a A. Vorobyov
,
A. Vorvolakos
,
M. Wadhwa
,
W. Wallraff
,
M. Wang
,
X L. Wang
,
Z M. Wang
,
A. Weber
,
M. Weber
,
P. Wienemann
,
H. Wilkens
,
S X. Wu
,
S. Wynhoff
,
L. Xia
,
Z Z. Xu
,
B Z. Yang
,
C G. Yang
,
H J. Yang
,
M. Yang
,
J B. Ye
,
S C. Yeh
,
J M. You
,
A. Zalite
,
Yu. Zalite
,
Z P. Zhang
,
G Y. Zhu
,
R Y. Zhu
,
A. Zichichi
,
F. Ziegler
,
G. Zilizi
,
M. Zoeller
M. Acciarri
- Function : Author
P. Achard
- Function : Author
O. Adriani
- Function : Author
M. Aguilar-Benitez
- Function : Author
J. Alcaraz
- Function : Author
G. Alemanni
- Function : Author
J. Allaby
- Function : Author
A. Aloisio
- Function : Author
M G. Alviggi
- Function : Author
G. Ambrosi
- Function : Author
H. Anderhub
- Function : Author
V P. Andreev
- Function : Author
T. Angelescu
- Function : Author
F. Anselmo
- Function : Author
A. Arefiev
- Function : Author
T. Azemoon
- Function : Author
T. Aziz
- Function : Author
P. Bagnaia
- Function : Author
L. Baksay
- Function : Author
R C. Ball
- Function : Author
S. Banerjee
- Function : Author
Sw. Banerjee
- Function : Author
A. Barczyk
- Function : Author
R. Barillere
- Function : Author
L. Barone
- Function : Author
P. Bartalini
- Function : Author
M. Basile
- Function : Author
R. Battiston
- Function : Author
A. Bay
- Function : Author
F. Becattini
- Function : Author
U. Becker
- Function : Author
F. Behner
- Function : Author
J. Berdugo
- Function : Author
P. Berges
- Function : Author
B. Bertucci
- Function : Author
B L. Betev
- Function : Author
S. Bhattacharya
- Function : Author
M. Biasini
- Function : Author
A. Biland
- Function : Author
- PersonId : 755137
- ORCID : 0000-0002-1288-833X
S C. Blyth
- Function : Author
G J. Bobbink
- Function : Author
A. Boehm
- Function : Author
L. Boldizsar
- Function : Author
B. Borgia
- Function : Author
D. Bourilkov
- Function : Author
M. Bourquin
- Function : Author
S. Braccini
- Function : Author
J G. Branson
- Function : Author
V. Brigljevic
- Function : Author
A. Buffini
- Function : Author
A. Buijs
- Function : Author
J D. Burger
- Function : Author
W J. Burger
- Function : Author
J. Busenitz
- Function : Author
A. Button
- Function : Author
X D. Cai
- Function : Author
M. Campanelli
- Function : Author
M. Capell
- Function : Author
G. Cara Romeo
- Function : Author
G. Carlino
- Function : Author
a M. Cartacci
- Function : Author
J. Casaus
- Function : Author
G. Castellini
- Function : Author
F. Cavallari
- Function : Author
N. Cavallo
- Function : Author
C. Cecchi
- Function : Author
M. Cerrada
- Function : Author
F. Cesaroni
- Function : Author
M. Chamizo
- Function : Author
y H. Chang
- Function : Author
U K. Chaturvedi
- Function : Author
A. Chen
- Function : Author
G. Chen
- Function : Author
G M. Chen
- Function : Author
H F. Chen
- Function : Author
H S. Chen
- Function : Author
G. Chiefari
- Function : Author
L. Cifarelli
- Function : Author
F. Cindolo
- Function : Author
C. Civinini
- Function : Author
I. Clare
- Function : Author
R. Clare
- Function : Author
a P. Colijn
- Function : Author
N. Colino
- Function : Author
S. Costantini
- Function : Author
F. Cotorobai
- Function : Author
B. Cozzoni
- Function : Author
B. de La Cruz
- Function : Author
A. Csilling
- Function : Author
S. Cucciarelli
- Function : Author
T S. Dai
- Function : Author
J A. van Dalen
- Function : Author
R. d'Alessandro
- Function : Author
R. de Asmundis
- Function : Author
P. Deglon
- Function : Author
K. Deiters
- Function : Author
D. Della Volpe
- Function : Author
P. Denes
- Function : Author
F. de Notaristefani
- Function : Author
A. de Salvo
- Function : Author
M. Diemoz
- Function : Author
D. van Dierendonck
- Function : Author
F. Di Lodovico
- Function : Author
C. Dionisi
- Function : Author
M. Dittmar
- Function : Author
A. Dominguez
- Function : Author
A. Doria
- Function : Author
M T. Dova
- Function : Author
P. Duinker
- Function : Author
I. Duran
- Function : Author
A. Engler
- Function : Author
F J. Eppling
- Function : Author
F C. Erne
- Function : Author
P. Extermann
- Function : Author
M. Fabre
- Function : Author
R. Faccini
- Function : Author
M A. Falagan
- Function : Author
S. Falciano
- Function : Author
A. Favara
- Function : Author
O. Fedin
- Function : Author
M. Felcini
- Function : Author
T. Ferguson
- Function : Author
F. Ferroni
- Function : Author
H. Fesefeldt
- Function : Author
E. Fiandrini
- Function : Author
J H. Field
- Function : Author
F. Filthaut
- Function : Author
P H. Fisher
- Function : Author
I. Fisk
- Function : Author
G. Forconi
- Function : Author
L. Fredj
- Function : Author
K. Freudenreich
- Function : Author
C. Furetta
- Function : Author
Yu. Galaktionov
- Function : Author
S N. Ganguli
- Function : Author
P. Garcia-Abia
- Function : Author
M. Gataullin
- Function : Author
S S. Gau
- Function : Author
S. Gentile
- Function : Author
N. Gheordanescu
- Function : Author
S. Giagu
- Function : Author
Z F. Gong
- Function : Author
O. Grimm
- Function : Author
M W. Gruenewald
- Function : Author
R. van Gulik
- Function : Author
V K. Gupta
- Function : Author
A. Gurtu
- Function : Author
L J. Gutay
- Function : Author
D. Haas
- Function : Author
A. Hasan
- Function : Author
D. Hatzifotiadou
- Function : Author
T. Hebbeker
- Function : Author
A. Herve
- Function : Author
P. Hidas
- Function : Author
J. Hirschfelder
- Function : Author
H. Hofer
- Function : Author
G. Holzner
- Function : Author
H. Hoorani
- Function : Author
S R. Hou
- Function : Author
I. Iashvili
- Function : Author
B N. Jin
- Function : Author
L W. Jones
- Function : Author
P. de Jong
- Function : Author
I. Josa-Mutuberria
- Function : Author
R A. Khan
- Function : Author
D. Kamrad
- Function : Author
M. Kaur
- Function : Author
M N. Kienzle-Focacci
- Function : Author
D. Kim
- Function : Author
D H. Kim
- Function : Author
J K. Kim
- Function : Author
S C. Kim
- Function : Author
J. Kirkby
- Function : Author
D. Kiss
- Function : Author
W. Kittel
- Function : Author
A. Klimentov
- Function : Author
a C. Koenig
- Function : Author
A. Kopp
- Function : Author
I. Korolko
- Function : Author
V. Koutsenko
- Function : Author
M. Kraeber
- Function : Author
R W. Kraemer
- Function : Author
W. Krenz
- Function : Author
A. Kunin
- Function : Author
P. Lacentre
- Function : Author
P. Ladron de Guevara
- Function : Author
G. Landi
- Function : Author
K. Lassila-Perini
- Function : Author
P. Laurikainen
- Function : Author
A. Lavorato
- Function : Author
M. Lebeau
- Function : Author
A. A. Lebedev
- Function : Author
P. Lebrun
- Function : Author
- PersonId : 741027
- IdHAL : patrice-jean-marie-lebrun
- ORCID : 0000-0001-6115-5856
P. Lecomte
- Function : Author
P. Lecoq
- Function : Author
P. Le Coultre
- Function : Author
H J. Lee
- Function : Author
J M. Le Goff
- Function : Author
R. Leiste
- Function : Author
Emilio Leonardi
- Function : Author
P. Levtchenko
- Function : Author
C. Li
- Function : Author
C H. Lin
- Function : Author
W T. Lin
- Function : Author
F L. Linde
- Function : Author
L. Lista
- Function : Author
Z A. Liu
- Function : Author
W. Lohmann
- Function : Author
E. Longo
- Function : Author
y S. Lu
- Function : Author
K. Luebelsmeyer
- Function : Author
C. Luci
- Function : Author
D. Luckey
- Function : Author
L. Luminari
- Function : Author
W. Lustermann
- Function : Author
W G. Ma
- Function : Author
M. Maity
- Function : Author
L. Malgeri
- Function : Author
A. Malinin
- Function : Author
C. Mana
- Function : Author
D. Mangeol
- Function : Author
P. Marchesini
- Function : Author
G. Marian
- Function : Author
F. Marzano
- Function : Author
G G G. Massaro
- Function : Author
K. Mazumdar
- Function : Author
R R. Mcneil
- Function : Author
S. Mele
- Function : Author
L. Merola
- Function : Author
M. Meschini
- Function : Author
W J. Metzger
- Function : Author
M. von Der Mey
- Function : Author
D. Migani
- Function : Author
A. Mihul
- Function : Author
H. Milcent
- Function : Author
G. Mirabelli
- Function : Author
J. Mnich
- Function : Author
G B. Mohanty
- Function : Author
P. Molnar
- Function : Author
B. Monteleoni
- Function : Author
T. Moulik
- Function : Author
F. Muheim
- Function : Author
a J M. Muijs
- Function : Author
M. Napolitano
- Function : Author
F. Nessi-Tedaldi
- Function : Author
H. Newman
- Function : Author
T. Niessen
- Function : Author
A. Nisati
- Function : Author
H. Nowak
- Function : Author
y D. Oh
- Function : Author
G. Organtini
- Function : Author
R. Ostonen
- Function : Author
C. Palomares
- Function : Author
D. Pandoulas
- Function : Author
S. Paoletti
- Function : Author
P. Paolucci
- Function : Author
H K. Park
- Function : Author
I H. Park
- Function : Author
G. Pascale
- Function : Author
G. Passaleva
- Function : Author
S. Patricelli
- Function : Author
T. Paul
- Function : Author
M. Pauluzzi
- Function : Author
C. Paus
- Function : Author
F. Pauss
- Function : Author
D. Peach
- Function : Author
M. Pedace
- Function : Author
y J. Pei
- Function : Author
S. Pensotti
- Function : Author
B. Petersen
- Function : Author
D. Piccolo
- Function : Author
M. Pieri
- Function : Author
P A. Piroue
- Function : Author
E. Pistolesi
- Function : Author
V. Plyaskin
- Function : Author
M. Pohl
- Function : Author
V. Pojidaev
- Function : Author
H. Postema
- Function : Author
J. Pothier
- Function : Author
N. Produit
- Function : Author
D O. Prokofiev
- Function : Author
D. Prokofiev
- Function : Author
J. Quartieri
- Function : Author
G. Rahal-Callot
- Function : Author
M A. Rahaman
- Function : Author
N. Raja
- Function : Author
R. Ramelli
- Function : Author
P G. Rancoita
- Function : Author
G. Raven
- Function : Author
P. Razis
- Function : Author
D. Ren
- Function : Author
M. Rescigno
- Function : Author
S. Reucroft
- Function : Author
T. van Rhee
- Function : Author
S. Riemann
- Function : Author
K. Riles
- Function : Author
A. Robohm
- Function : Author
J. Rodin
- Function : Author
B P. Roe
- Function : Author
L. Romero
- Function : Author
A. Rosca
- Function : Author
J A. Rubio
- Function : Author
D. Ruschmeier
- Function : Author
H. Rykaczewski
- Function : Author
S. Sarkar
- Function : Author
J. Salicio
- Function : Author
E. Sanchez
- Function : Author
M P. Sanders
- Function : Author
M E. Sarakinos
- Function : Author
C. Schaefer
- Function : Author
V. Schegelsky
- Function : Author
S. Schmidt-Kaerst
- Function : Author
D. Schmitz
- Function : Author
H. Schopper
- Function : Author
D J. Schotanus
- Function : Author
J. Schwenke
- Function : Author
G. Schwering
- Function : Author
C. Sciacca
- Function : Author
D. Sciarrino
- Function : Author
A. Seganti
- Function : Author
L. Servoli
- Function : Author
S. Shevchenko
- Function : Author
N. Shivarov
- Function : Author
V. Shoutko
- Function : Author
E. Shumilov
- Function : Author
A. Shvorob
- Function : Author
T. Siedenburg
- Function : Author
D. Son
- Function : Author
B. B.N. Smith
- Function : Author
P. Spillantini
- Function : Author
M. Steuer
- Function : Author
D P. Stickland
- Function : Author
A. Stone
- Function : Author
H. Stone
- Function : Author
B. Stoyanov
- Function : Author
A. Straessner
- Function : Author
K. Sudhakar
- Function : Author
G. Sultanov
- Function : Author
L Z. Sun
- Function : Author
H. Suter
- Function : Author
J D. Swain
- Function : Author
Z. Szillasi
- Function : Author
X W. Tang
- Function : Author
L. Tauscher
- Function : Author
L. Taylor
- Function : Author
C. Timmermans
- Function : Author
S C C. Ting
- Function : Author
S M. Ting
- Function : Author
S C. Tonwar
- Function : Author
J. Toth
- Function : Author
C. Tully
- Function : Author
K L. Tung
- Function : Author
Y. Uchida
- Function : Author
J. Ulbricht
- Function : Author
E. Valente
- Function : Author
G. Vesztergombi
- Function : Author
I. Vetlitsky
- Function : Author
D. Vicinanza
- Function : Author
G. Viertel
- Function : Author
S. Villa
- Function : Author
S. Vlachos
- Function : Author
I. Vodopianov
- Function : Author
H. Vogel
- Function : Author
H. Vogt
- Function : Author
I. Vorobiev
- Function : Author
a A. Vorobyov
- Function : Author
A. Vorvolakos
- Function : Author
M. Wadhwa
- Function : Author
W. Wallraff
- Function : Author
M. Wang
- Function : Author
X L. Wang
- Function : Author
Z M. Wang
- Function : Author
A. Weber
- Function : Author
M. Weber
- Function : Author
P. Wienemann
- Function : Author
H. Wilkens
- Function : Author
S X. Wu
- Function : Author
S. Wynhoff
- Function : Author
L. Xia
- Function : Author
Z Z. Xu
- Function : Author
B Z. Yang
- Function : Author
C G. Yang
- Function : Author
H J. Yang
- Function : Author
M. Yang
- Function : Author
- PersonId : 755143
- ORCID : 0000-0003-4365-3282
J B. Ye
- Function : Author
S C. Yeh
- Function : Author
J M. You
- Function : Author
A. Zalite
- Function : Author
Yu. Zalite
- Function : Author
Z P. Zhang
- Function : Author
G Y. Zhu
- Function : Author
R Y. Zhu
- Function : Author
A. Zichichi
- Function : Author
F. Ziegler
- Function : Author
G. Zilizi
- Function : Author
M. Zoeller
- Function : Author
Abstract
The two-photon width $\Gamma_{\gamma\gamma}$ of the $\eta_{\mathrm{c}}$ meson has been measured with the L3 detector at LEP. The $\eta_{\mathrm{c}}$ is studied in the decay modes $\pi^+\pi^-\pi^+\pi^-$, $\pi^+\pi^-$K$^+$K$^-$, K$_s^0$K$^\pm\pi^\mp$, K$^+$K$^-\pi^{0}$, $\pi^+\pi^-\eta$, $\pi^+\pi^-\eta'$, and $\rho^+\rho^-$ using an integrated luminosity of 140 pb$^{-1}$ at $\sqrt{s} \simeq 91$ GeV and of 52 pb$^{-1}$ at $\sqrt{s} \simeq 183$ GeV. The result is $\Gamma_{\gamma\gamma}(\eta_{\mathrm{c}}) = 6.9 \pm 1.7 \mbox{(stat.)} \pm 0.8 \mbox{(sys.)} \pm 2.0$(BR) keV. The $Q^2$ dependence of the $\eta_{\mathrm{c}}$ cross section is studied for $Q^2 < 9$ GeV$^{2}$. It is found to be better described by a Vector Meson Dominance model form factor with a J-pole than with a $\rho$-pole. In addition, a signal of $29 \pm 11$ events is observed at the $\chi_{\mathrm{c}0}$ mass. Upper limits for the two-photon widths of the $\chi_{\mathrm{c}0}$, $\chi_{\mathrm{c}2}$, and $\eta_{\mathrm{c}}'$ are also given.