-
A. Agababyan,
G. Asova,
G. Dimitrov,
G. Grygiel,
B Fominykh,
O. Hensler,
R. Kammering,
L. Petrosyan,
K. Rehlich,
V. Rybnikov,
G Trowitzsch, M Winde,
T. Wilksen
[show abstract]
[hide abstract]
ABSTRACT: Free electron LASer in Hamburg (FLASH) at DESY is a user facility with laser-like radiation source in the VUV and soft X-ray range. It is also a pilot facility for the future XFEL. A fast data acquisition system (DAQ) to support the accelerator operation and the user experiments was developed. The system collects data from hundreds of ADC channels in the range of 1 M up to 2 G samples per second. In addition it allows collecting images from digital video cameras. All the data is collected in a shared memory of a central multiprocessor computer. Several processes are used to calculate e.g., the orbit, energy or photon flux, or are used as feedback loops to improve the stability of the linac. A long time archiving of the collected data from the accelerator and from the FEL experiments on a 24 TB disk and finally on a tape is provided. The whole system is integrated in the DOOCS control system of FLASH. It is a novel approach to combine a fast DAQ system with a accelerator control system.
IEEE Transactions on Nuclear Science 03/2008; 55(1):256-260. · 1.45 Impact Factor
-
J. E. Turney,
E. Tzamariudaki,
S. Udluft,
A. Usik,
S. Valkar,
A. Valkarova,
C. Vallee,
P. Van Mechelen,
Y. Vazdik,
G. Villet, [......],
H. Wollatz,
E. Wunsch,
J. Zacek,
J. Zalesak,
Z. Zhang,
A. Zhokin,
P. Zini,
F. Zomer,
J. Zsembery,
M. zur Nedden
[show abstract]
[hide abstract]
ABSTRACT: The production of hard di-jet events in photoproduction at HERA is
dominated by resolved photon processes in which a parton in the photon
with momentum fraction x_gamma is scattered from a parton in the proton.
These processes are sensitive to the quark and gluon content of the
photon. The differential di-jet cross-section dsigma/dlog(x_gamma) is
presented here, measured in tagged photoproduction at HERA using data
taken with the H1 detector, corresponding to an integrated luminosity of
7.2 pb^(-1). Using a restricted data sample at high transverse jet
energy, E_(T,jet)>6 GeV, the effective parton density
f_gamma,eff(x_gamma) = [q(x_gamma) + bar(q)(x_gamma) +9/4g(x_gamma)] in
the photon in leading order QCD is measured down to x_gamma=0.05 from
which the gluon density in the photon is derived.
Physics Letters B 05/2000; 483:36-48. · 3.95 Impact Factor
-
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
-
Collaboration,
S. Aid,
V. Andreev,
B. Andrieu,
R. D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban, [......],
E. Wünsch,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: A search for squarks ofR-parity violating supersymmetry is performed inep collisions at HERA using H1 1994e
+ data. Direct single production of squarks of each generation bye
+-quark fusion via a Yukawa coupling λ′ is considered. All possibleR-parity violating decays and gauge decays of the squarks are taken into account. No significant deviation from the Standard
Model predictions is found in the various multi-lepton and multi-jet final states studied and exclusion limits are derived.
At 95% confidence level, the existence of first generation squarks is excluded for masses up to 240 GeV for coupling values
λ′≳√4πα
em. The limits obtained are shown to be only weakly dependent on the free parameters of the Minimal Supersymmetric Standard
Model. Stop squarks are excluded for masses up to 138 GeV for coupling λ′×cosθ
t toe
+d pairs ≳0.1×√4πα
em, whereθ
t is the mass mixing angle.
Light stop squarks are furthermore searched for through pair production inγ-gluon fusion processes. No signal is observed and exclusion limits are derived. Masses in the range 9 to 24.4 GeV are excluded
at 95% confidence level for λ′×cosθ
t>10−4.
Zeitschrift für Physik C 05/1996; 71(2):211-226.
-
Collaboration,
C. Adloff,
S. Aid,
M. Anderson,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
C. Arndt,
A. Babaev,
J. Bähr, [......],
E. Wünsch,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
P. Zini,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: First results on inclusiveD0 ( - )\mathop {D^0 }\limits^{( - )} andD*± production in neutral current deep inelasticep scattering are reported using data collected by the H1 experiment at HERA in 1994. Differential cross sections are presented
for both channels and are found to agree well with QCD predictions based on the boson gluon fusion process. A charm production
cross section for 10 GeV2≤Q2≤100 GeV2 and 0.01≤y≤0.7 ofs(ep ® ec[`(c)]X) = (17.4 ±1.6 ±1.7 ±1.4) nb\sigma (ep \to ec\bar cX) = (17.4 \pm 1.6 \pm 1.7 \pm 1.4) nb is derived. A first measurement of the charm contributionF2c[`(c)] (x,Q2 )F_2^{c\bar c} (x,Q^2 ) to the proton structure function for Bjorkenx between 8·10−4 and 8·10−3 is presented. In this kinematic range a ratioF2c[`(c)] /F2 = 0.237 ±0.021 ±0.041F_2^{c\bar c} /F_2 = 0.237 \pm 0.021 \pm 0.041 is observed.
Zeitschrift für Physik C 04/1996; 72(4):593-605.
-
Collaboration,
S. Aid,
M. Anderson,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban, [......],
E. Wünsch,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
P. Zini,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastice
+
p scattering have been measured over a large kinematical region. The evolution withW andQ
2 of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in
the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target
lepton-nucleon interactions,e
+
e
− annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the Negative
Binomial and Lognormal distributions are presented.
Zeitschrift für Physik C 04/1996; 72(4):573-592.
-
S. Aid,
V. Andreev,
B. Andrieu,
R.-D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban,
P. Baranov, [......],
C. Wittek,
E. Wünsch,
J. ŽáČek,
D. Zarbock,
Z. Zhang,
A. Zhokin,
F. Zomer,
J. Zsembery,
K. Zuber,
M. Zurnedden
[show abstract]
[hide abstract]
ABSTRACT: At the electron-proton collider HERA the inclusive D*+/-
meson photoproduction cross section has been measured with the H1
detector in two different, but partly overlapping, kinematical regions.
For the first, where ≈ 200 GeV and
Q2 < 0.01 GeV2, the result is σ (γp
->ccX ) = (13.2 +/- 2.2+2.1 + 9.9-1.7 -4.8)
μb. The second measurement for Q2 < 4 GeV2
yields σ(γp ->ccX ) = (9.3+/-2.1+1.9
+6.9-1.8 -3.2) μb at
≈ 142 GeV and σ(γp -> ccX) = (20.6+/-5.5+4.3
+15.4-3.9 -7.2) μb at
≈ 230 GeV, respectively. The third error accounts for an additional
uncertainty due to the proton and photon parton density
parametrizations. Differential cross sections are presented as a
function of the D*+/- transverse momentum and rapidity. The
results compare reasonably well with next-to-leading order QCD
calculations. Evidence for diffractive photoproduction of charm quarks
is presented.
Nuclear Physics B 01/1996; 472:32-51. · 4.66 Impact Factor
-
Collaboration,
S. Aid,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban, [......],
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton
collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to[`(p)]p\bar pp data and QCD calculations. The comparisons show that theγp events can be consistently described by QCD models including — in addition to the primary hard scattering process — interactions
between the two beam remnants. The differential jet cross sectionsdσ/dE
Tjet anddσ/dη
jet are measured.
Zeitschrift für Physik C 01/1996; 70(1):17-30.
-
Collaboration,
S. Aid,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban, [......],
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: We present a new measurement of the total photoproduction cross section performed with the H1 detector at HERA. For an average
centre of mass energy of 200 GeV a value of σ
tot
λp
=165±2±11µb has been obtained. A detailed analysis of the data in adequate kinematic regions enabled a decomposition of the total cross
section in its elastic, single diffractive dissociation and remaining non-diffractive parts, based on safe assumptions on
the double diffractive dissociation contribution.
Zeitschrift für Physik C 11/1995; 69(1):27-38.
-
S. Aid,
V. Andreev,
B. Andrieu,
R. D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban,
P. Baranov, [......],
T. P. Yiou,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: The cross sections for the charged current processes {ie566-1} and, for the first time, {ie566-2} are measured at HERA for transverse momenta larger than 25 GeV.
Zeitschrift für Physik C 11/1995; 67(4):565-575.
-
T. Ahmed,
S. Aid,
V. Andreev,
B. Andrieu,
R. -D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Baehr,
J. Bán,
P. Baranov, [......],
N. Wulff,
T. P. Yiou,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
K. Zuber
[show abstract]
[hide abstract]
ABSTRACT: We present an experimental study of theepe+p andepe+X processes using data recorded by the H1 detector in 1993 at the electron-proton collider HERA. These processes are employed to measure the luminosity with an accuracy of 4.5 %. A subsample of theepe+X events in which the hard photon is detected at angles
0.45 mrad with respect to the incident electron direction is used to verify experimentally the size of radiative corrections to theepeX inclusive cross section and to investigate the structure of the proton in theQ
2 domain down to 2 GeV2, lower than previously attained at HERA.
Zeitschrift für Physik C 01/1995; 66(4):529-542.
-
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.
-
[show abstract]
[hide abstract]
ABSTRACT: A proposal is described to upgrade the existing H1 tracking
detector by a semiconductor backward tracking telescope consisting of 8
beam-concentric disks to measure the gluon and quark distribution
functions at very low Bjorken x . Each disk comprises three
planes of strip and pad silicon detectors made of 4-in wafers in order
to determine the polar angle and the transverse momentum, and to trigger
on deep inelastically scattered electrons. The simulation work and the
layout constraints on the semiconductors are discussed. The technical
and electronics design of the trigger is reviewed. It has to cope with
very high beam background rates and the HERA bunch crossing rate of 10.4
MHz
IEEE Transactions on Nuclear Science 09/1993; · 1.45 Impact Factor
-
J. Burger,
S. Prell,
M. Zimmer,
W. Zimmermann,
H. Henschel,
H.H. Kaufmann,
M. Klein,
P. Kostka,
W. Lange,
H. Lippold, [......],
D. Clarke,
W.J. Haynes,
P. Hill,
L. Joensson,
K. Gabathuler,
R. Horisberger,
M. Wagener,
R. Eichler,
W. Erdmann,
D. Pitzl
Nuclear Science Symposium and Medical Imaging Conference, 1993., 1993 IEEE Conference Record.;
-
T. Ahmed,
S. Aid,
V. Andreev,
B. Andrieu,
R.-D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Baehr,
J. Bán,
P. Baranov, [......],
N. Wulff,
T.P. Yiou,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
K. Zuber
[show abstract]
[hide abstract]
ABSTRACT: Jet rates in deep inelastic electron proton scattering are studied with the H1 detector at HERA for momentum transfers squared between 10 and 4000 GeV2. It is shown that they can be quantitatively described by perturbative QCD in next to leading order making use of the parton densities of the proton and with the strong coupling constant αs as a free parameter. The measured value, αs(MZ2) = 0.123 ± 0.018, is in agreement both with determinations from e+e− annihilation at LEP using the same observable and with the world average.
Physics Letters B.
-
S. Aid,
V. Andreev,
B. Andrieu,
R.-D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban,
P. Baranov, [......],
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
M. Zimmer,
W. Zimmermann,
F. Zomer,
J. Zsembery,
K. Zuber,
M. zurNedden
[show abstract]
[hide abstract]
ABSTRACT: Photon-proton (γp) interactions with < 10−2 GeV2 and deep-inelastic scattering (γ∗p) interactions with photon virtualities > 5 GeV2 are studied at the high energy electron-proton collider HERA. The transverse energy flow and relative rates of large rapidity gap events are compared in the two event samples. The observed similarity between γp and γ∗p interactions can be understood in a picture where the photon develops as a hadronic object. The transverse energy density measured in the central region of the collision, at η∗ = 0 in the γ∗p centre of mass frame, is compared with data from hadron-hadron interactions as function of the CMS energy of the collision.
Physics Letters B.
-
S Aid,
M Anderson,
V Andreev,
B Andrieu,
A Babaev,
J Bähr,
J Bán,
Y Ban,
P Baranov,
E Barrelet, [......],
E Wünsch,
J Žáček,
D Zarbock,
Z Zhang,
A Zhokin,
P Zini,
F Zomer,
J Zsembery,
K Zuber,
M ZurNedden
[show abstract]
[hide abstract]
ABSTRACT: The scale dependence of the evolution of photoproduction cross sections with the photon-proton centre of mass energy W is studied using low Q2 < 0.01 GeV2e+p interactions collected by the H1 experiment at HERA. The value of the largest transverse momentum of a charged particle in the photon fragmentation region is used to define the hard scale. The slope of the W dependence of the cross section is observed to increase steeply with increasing transverse momentum. The result is compared to measurements of the Q2 evolution of the W dependence of the virtual photon-proton cross section. Interpretations in terms of QCD and in terms of Regge phenomenology are discussed.
Physics Letters B.
-
S. Aid,
V. Andreev,
B. Andrieu,
R.-D. Appuhn,
M. Arpagaus,
A. Babaev,
J. Bähr,
J. Bán,
Y. Ban,
P. Baranov, [......],
C. Wittek,
E. Wünsch,
J. Žáček,
D. Zarbock,
Z. Zhang,
A. Zhokin,
F. Zomer,
J. Zsembery,
K. Zuber,
M. ZurNedden
[show abstract]
[hide abstract]
ABSTRACT: The Q2 dependence and the total cross sections for charged and neutral current processes are measured in e±p reactions for transverse momenta of the outgoing lepton larger than 25 GeV. Comparable size of cross sections for the neutral current process and for the weak charged current process are observed above Q2 ∥ 5000 GeV2. Using the shape and magnitude of the charged current cross section we determine a propagator mass of mW = 84−7+10 GeV.
Physics Letters B.
-
A. Agababyan,
DESY Maschinenphysik,
G. Asova,
G. Dimitrov,
G. Grygiel,
B Fominykh,
O. Hensler,
R. Kammering,
L. Petrosyan,
K. Rehlich,
V. Rybnikov,
G Trowitzsch, M Winde,
T. Wilksen
15th IEEE NPSS Real Time Confrence 2007,Batavia, IL,USA (2007),1-5.
