-
I. Abt,
T. Ahmed,
S. Aid,
V. Andreev,
B. Andrieu,
R.-D. Appuhn,
C. Arnault,
M. Arpagaus,
A. Babaev,
H. Bärwolff, [......],
J. ŽáČek,
D. Zarbock,
P. Závada,
C. Zeitnitz,
Z. Zhang,
H. Ziaeepour,
M. Zimmer,
W. Zimmermann,
F. Zomer,
K. Zuber
[show abstract]
[hide abstract]
ABSTRACT: Technical aspects of the three major components of the H1 detector at
the electron-proton storage ring HERA are described. This paper covers
the detector status up to the end of 1994 when a major upgrading of some
of its elements was undertaken. A description of the other elements of
the detector and some performance figures from luminosity runs at HERA
during 1993 and 1994 are given in a paper previously published in this
journal.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/1997; 386:348-396. · 1.21 Impact Factor
-
I. Abt,
T. Ahmed,
V. Andreev,
S. Aid,
B. Andrieu,
R. -D. Appuhn,
M. Arpagaus,
A. Babaev,
H. Bärwolff,
J. Bán, [......],
L. A. Womersley,
A. E. Wright,
N. Wulff,
T. P. Yiou,
J. Žáček,
C. Zeitnitz,
H. Ziaeepour,
M. Zimmer,
W. Zimmermann,
F. Zomer
[show abstract]
[hide abstract]
ABSTRACT: Global properties of the hadronic final state in deep inelastic scattering events at HERA are investigated. The data are corrected for detector effects and are compared directly with QCD phenomenology. Energy flows in both the laboratory frame and the hadronic centre of mass system and energy-energy correlations in the laboratory frame are presented. Comparing various QCD models, the colour dipole model provides the only satisfactory description of the data. In the hadronic centre of mass system the momentum components of charged particles longitudinal and transverse to the virtual boson direction are measured and compared with lower energy lepton-nucleon scattering data as well as withe
+
e
– dat from LEP.
Zeitschrift für Physik C 08/1994; 63(3):377-389.
-
I. Abt,
T. Ahmed,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
M. Arpagaus,
A. Babaev,
H. Bärwolff,
J. Bán,
P. Baranov, [......],
A. E. Wright,
N. Wulff,
T. P. Yiou,
J. Žáček,
P. Závada,
C. Zeitnitz,
H. Ziaeepour,
M. Zimmer,
W. Zimmermann,
F. Zomer
[show abstract]
[hide abstract]
ABSTRACT: Multi-jet production is observed in deep-inelastic electron proton scattering with the H1 detector at HERA. Jet rates for momentum transfers squared up to 500 GeV2 are determined using the JADE jet clustering algorithm. They are found to be in agreement with predictions from QCD based models.
Zeitschrift für Physik C 01/1994; 61(1):59-66.
-
H. -J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
J. H. Peters,
O. Podobrin,
V. Schröder,
G. G. Winter, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: Using the CELLO detector, we have measured cross sections for the process
+
– in the mass range 0.75–1.9 GeV/c2. A partial wave fit to the data indicates the presence of a sizeableS-wave amplitude with signs of resonant behaviour. Values for the width of thef
2(1270) are given, showing the model-dependence of this quantity. At higher dipion masses, the model of Brodsky and Lepage is found to give an order of magnitude description of the data.
Zeitschrift für Physik C 08/1992; 56(3):381-390.
-
H.-J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We present measurement of the 0*, * and * form factors. The 0-form factor is for the first time observed in the space-like region. The transition form factor of the -meson is determined from its decay modes +–0, +– and the neutral decay mode . The decay of the is observed in the decay channels , +– with and in the four charged prong final state stemming from +– with the decaying into +–(0/). All form factors agree well with a simple -pole predicted by the vector meson dominance model and also with the QCD inspired Brodsky-Lepage model.
Zeitschrift für Physik C 08/1991; 49(3):401-409.
-
H. J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We have studied the reactione
+
e
–e
+
e
– using data taken by the CELLO detector at 35 GeV centre of mass energy with an integrated luminosity of 86 pb–1. The differential cross section is found to agree with the Standard Model and is used to set limits on possible deviations from the pointlike structure of the electron. The lower limits obtained for the compositeness scale range from 0.8 to 6.0 TeV (95% C.L.), depending on the structure of the current.
Zeitschrift für Physik C 05/1991; 51(2):143-148.
-
H. -J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We have measured the cross section andQ
2-dependence of the reaction multihadrons, using the CELLO detector at DESY, for visible final-state masses between 4 and 9 GeV. The data are well fitted by an incoherent sum of Generalised Vector Meson Dominance and Quark Parton Model terms, but at lowQ
2 require the addition of a third component which resembles the QPM but is less two-jet-like. With and without this term, the GVDM cross section atQ
2=0 is found to be 20020 and 25025 nb, respectively.
Zeitschrift für Physik C 01/1991; 51(3):365-375.
-
H. J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: Differential cross section data of the CELLO experiment on pair production of muons, taus, and heavy quarks ine
+
e
–-annihilation are presented and analysed, together with our data on Bhabha scattering, in terms of compositeness effects characterized by the mass scale . We discuss difficulties in the combination of limits from different experiments. The appropriate parameter to combine different results turns out to be =1/
2, which is in contrast to Gaussian distributed.
Zeitschrift für Physik C 01/1991; 51(2):149-156.
-
H. -J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: The reactione
+
e
–e
+
e
–+–0 in the untagged mode has been measured with the CELLO detector at PETRA. The cross section is dominated by exclusivea
2(1320) production, whose radiative width is determined to be
=1.000.07(stat.)0.15(syst.)keV. An angular correlation analysis indicates pure helicity 2 with an upper limit on the helicity 0 contribution of 8.2% (at 95% c.l.). Excitation of the pseudotensor meson
2
0
(1670) is observed for the first time in this reaction. The 2 radiative width and its dependence on interference effects are studied.
Zeitschrift für Physik C 11/1990; 46(4):583-591.
-
H. J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We present high precision results from an analysis of all major Ös = 35 GeV\sqrt s = 35 GeV
, using the CELLO detector at PETRA. The sum of the measured exclusive branching ratios saturates the total decay width. In a comparison with the topological branching ratios measured recently by CELLO, the sums of the respective exclusive branching ratios are found to saturate the inclusive fractions. Our results are in good general agreement with existing measurements. However, the decay fractions for ––+–
v
, and ––00
v
are larger than the present world averages. All measured branching ratios are in good agreement with the expectations from a standard lepton.
Zeitschrift für Physik C 11/1990; 46(4):537-546.
-
H. J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: The production ofb andc quarks ine
+
e
– annihilation has been studied with the CELLO detector in the range from 35 GeV up to the highest PETRA energies. The heavy quarks have been tagged by their semileptonic decays. The charge asymmetries forb quarks at 35 and 43 GeV have been found to beA
b
=–(22.28.1)% andA
b
=–(49.116.5)%, respectively, using a method incorporating jet variables and their correlations for the separation of the heavy quarks from the back ground of the lighter quarks. Forc quarks we obtainA
c
=–(12.98.8)% andA
c
=+(7.714.0)%, respectively. The axial vector coupling constants of the heavy quarksc andb are found to bea
c
=+(0.290.46) anda
b
=–(1.150.41) taking
B0[`(B0 )]B^0 \overline {B^0 }
mixing into account. The results are in agreement with the expectations from the standard model.
Zeitschrift für Physik C 08/1990; 47(3):333-342.
-
H. -J. Behrend,
L. Criegee,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
O. Podobrin,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We present an analysis of strange particle production frome
+
e
– annihilation into multihadronic final states. The experiment was performed with the CELLO detector at the PETRA storage ring at DESY, the data was taken at a centre of mass energy of 35 GeV with an integrated luminosity of 86 pb–1. The particlesK
S
0
,K
* and have been identified by their characteristic decays, and differential cross sections for their production have been obtained. From a comparison ofK
S
0
andK
* rates the Lund vector meson suppression parameterV/(V+P)
S
has been determined.
Zeitschrift für Physik C 08/1990; 46(3):397-403.
-
H. J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We have measured the inclusive production of , 0 and ine
+
e
– annihilation at the center of mass energy of 35 GeV. The differential cross sections, extended to the kinematical limit and measured with high accuracy, are found to be in good agreement with previously reported results. Using the measured spectra we determine the average multiplicity for each of these particle species.
Zeitschrift für Physik C 02/1990; 47(1):1-10.
-
CELLO Collaboration,
H. -J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter, [......],
G. Cozzika,
Y. Ducros,
F. Pierre,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milstène
[show abstract]
[hide abstract]
ABSTRACT: The three reactionse
+e−→e
+e−e+e−,e
+
e
-→e
+
e
-μ+μ- ande
+
e
-→μ+μ-μ+ μ- have been studied using the CELLO detector at PETRA. The data correspond to 130 pb−1 collected at energies ranging from 35 GeV to 46.8 GeV. A detailed analysis of the distribution of the observed events in
phase space shows good agreement with QED to order α4.
Zeitschrift für Physik C 02/1989; 43(1):1-14.
-
H. J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: Multihadronic events measured with the CELLO detector in the energy range 14 to 46 GeV have been analyzed in terms of thrust, jet masses and the asymmetry of the energy-energy correlation. The data have been compared with 2nd order QCD calculations. From a study of the general properties of fragmentation effects, model-independent limits on Ös = 35\sqrt s = 35
GeV). The dependence of these results on the renormalization scheme is discussed.
Zeitschrift für Physik C 02/1989; 44(1):63-69.
-
CELLO Collaboration,
H. -J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: In the reaction γγ→K
S
0
K
S
0
resonance production of thef
2
−
is observed. For the radiative with
$\Gamma _{\gamma \gamma } .B(f'_2 \to K\bar K) = 0.11_{ - 0.02}^{ + 0.03} \pm 0.02keV$\Gamma _{\gamma \gamma } .B(f'_2 \to K\bar K) = 0.11_{ - 0.02}^{ + 0.03} \pm 0.02keV
is found. The small number of events in thef
2,a
2 mass region is consistent with the assumption of destructivef
2−a
2 interference. From the mass distribution we determine the relative phases between the tensor mesons. Upper limits on the
radiative widths of the glueball candidatesf
2(1720) andX (2220) are derived.
Zeitschrift für Physik C 02/1989; 43(1):91-96.
-
H.-J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: Results on the reaction
γγ-->π+π-π0π0
are presented. There is clear evidence for correlated
ϱ+ϱ- production. The cross section is
much lower than for
γγ-->ϱ0ϱ0.
Physics Letters B 02/1989; 218:493-498. · 3.95 Impact Factor
-
H. J. Behrend,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
G. G. Winter,
P. J. Bussey, [......],
B. Stella,
G. Cozzika,
Y. Ducros,
G. Alexander,
A. Beck,
G. Bella,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: We have searched for resonance production in the reaction Ggghc \Gamma _{\gamma \gamma }^{\eta _c }
keV (95% c.l.) is obtained. For the glueball candidate Gggh(1440) B(h(1440) ® K[`(K)]p) < 1.2keV(95% c.l.)\Gamma _{\gamma \gamma }^{\eta (1440)} B(\eta (1440) \to K\bar K\pi )< 1.2keV(95\% c.l.)
is derived. In the tagged data sample resonance formation of a spin 1 state at 1420 MeV is observed, which is absent in the untagged data. The mass and width of this state are consistent with those of thef
1(1420); an analysis of decay angular distributions favours positive parity.
Zeitschrift für Physik C 01/1989; 42(3):367-376.
-
H. -J. Behrend,
J. Bürger,
L. Criegee,
J. B. Dainton,
J. H. Field,
G. Franke,
H. Jung,
J. Meyer,
V. Schröder,
U. Timm, [......],
F. Ould Saada,
F. Pierre,
J. Záček,
G. Alexander,
G. Bella,
Y. Gnat,
J. Grunhaus,
A. Klatchko,
A. Levy,
C. Milsténe
[show abstract]
[hide abstract]
ABSTRACT: A search for new leptons, charged and neutral, produced ine
+
e
– collisions at an average c.m. energy of 44.2 GeV, has been carried out with the CELLO detector at PETRA. No such particles have been observed: we exclude pair production of new charged leptons at the 95% C.L. in the mass range 1.5–22.0 GeV/c2 and of neutral leptons in the mass range 3.1–18.0 GeV/c2. Single production of a heavy neutrino together with a standard neutrino has also been studied; we exclude an electron-like neutral lepton in the mass ranges 0.6–34.6 GeV/c2 forV—A coupling to theW boson, and 0.4–37.4 GeV/c2 forV+A coupling.
Zeitschrift für Physik C 02/1988; 41(1):7-16.
-
H. -I. Behrend,
J. Bürger,
L. Criegee,
J. B. Dainton,
H. Fenner,
J. H. Field,
G. Franke,
J. Meyer,
V. Schröder,
U. Timm, [......],
Y. Ducros,
Y. Lavagne,
F. Ould Saada,
J. Žáĉek,
G. Alexander,
G. Bella,
Y. Gnat,
J. Grunhaus,
A. Klatchko,
A. Levy
[show abstract]
[hide abstract]
ABSTRACT: Mass limits are presented for various supersymmetric particles: scalar partners of electrons, muons, taus and quarks; photinos, winos and zinos. They were obtained from the analysis of an exposure of 48.6 pb–1 of the CELLO detector at the PETRAe
+
e
– storage ring up to a center of mass energy of 46.8 GeV. Special attention has been given to the case where the photino is assumed to be the lightest supersymmetric particle, but other possibilities have also been considered.
Zeitschrift für Physik C 05/1987; 35(2):181-199.
