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137
result(s) for
"Kostka, P."
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An experiment for electron-hadron scattering at the LHC
Novel considerations are presented on the physics, apparatus and accelerator designs for a future, luminous, energy frontier electron-hadron (eh) scattering experiment at the LHC in the thirties for which key physics topics and their relation to the hadron-hadron HL-LHC physics programme are discussed. Demands are derived set by these physics topics on the design of the LHeC detector, a corresponding update of which is described. Optimisations on the accelerator design, especially the interaction region (IR), are presented. Initial accelerator considerations indicate that a common IR is possible to be built which alternately could serve eh and hh collisions while other experiments would stay on hh in either condition. A forward-backward symmetrised option of the LHeC detector is sketched which would permit extending the LHeC physics programme to also include aspects of hadron-hadron physics. The vision of a joint eh and hh physics experiment is shown to open new prospects for solving fundamental problems of high energy heavy-ion physics including the partonic structure of nuclei and the emergence of hydrodynamics in quantum field theory while the genuine TeV scale DIS physics is of unprecedented rank.
Journal Article
Changes in electric resistance of cracked copper-coated, pitch-based carbon fibres for structural health monitoring in a glider wing
Structural health monitoring based on detecting strain enables further exploitation of the lightweight potential of aircraft structures. Since carbon fibres (CF) can be easily integrated into aircraft structures made of fibre-reinforced plastics (FRP), their use in sensor applications has become subject of research. One of many novel approaches is the use of cracked CF for strain detection. During loading and unloading, the fibre cracks are opening and closing respectively, resulting in substantial changes in the electric resistance of the CF. The high dependence of the electric resistance on the mechanical strain enables spatially resolved strain sensing along the CF based on the electric time domain reflectometry (ETDR) principle. However, due to high inhomogeneity of the used pitch-based CF and the resulting electric properties, the ETDR-signal is degraded largely by impedance mismatch along the transmission line, which limits the measuring length of a spatially resolved sensor. In this contribution, a concept for a spatially resolved CF-based strain sensor is described, outlining the challenges that need to be addressed. One approach for the extension of the measuring length is lowering the base resistivity of the used CF, which is discussed in detail. In order to achieve a low base resistivity while maintaining the characteristic of opening and closing fibre cracks, copper-coated CF are investigated. The copper-coated pitch-based CF are integrated into test specimens consisting of a composite material and are subjected to tensile loading. Simultaneously to the deflection, the electrical resistance is measured. Consequently, the sensitivity to strain of the CF is determined and discussed.
Journal Article
Lifetime testing of a flexure based natural gas fired 1 kW thermoacoustic genset
Etalim has developed and lifetime tested a flexure-based thermoacoustic (TAC) genset operating at high pressure and frequency. It is an efficient and practical 1 kWe genset ready for deployment as a genset or a micro-cogeneration system when integrated with a recuperated natural gas burner and stroke controlling power electronics. It is a maintenancefree, extreme reliability genset particularly suited for remote power applications. The genset is fully costed and designed for manufacturing. Fuel-to-electric efficiency of 22% has been achieved, and one remaining avenue for significant improvement identified. A test TAC has been run for a cumulative time of about 8000 hours to date without any component failures.
Journal Article
Measurement of exclusive π+π- and ρ0 meson photoproduction at HERA
Exclusive photoproduction of ρ0(770) mesons is studied using the H1 detector at the ep collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction γp→π+π-Y. Reactions where the proton stays intact (mY=mp) are statistically separated from those where the proton dissociates to a low-mass hadronic system (mp
Journal Article
Determination of the strong coupling constant αs(mZ) in next-to-next-to-leading order QCD using H1 jet cross section measurements
The strong coupling constant
α
s
is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic
ep
scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of
α
s
(
m
Z
)
at the
Z
-boson mass
m
Z
are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be
α
s
(
m
Z
)
=
0.1157
(
20
)
exp
(
29
)
th
. Complementary,
α
s
(
m
Z
)
is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value
α
s
(
m
Z
)
=
0.1142
(
28
)
tot
obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.
Journal Article
Measurement of jet production cross sections in deep-inelastic ep scattering at HERA
A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities
5.5
<
Q
2
<
80
GeV
2
and inelasticities
0.2
<
y
<
0.6
is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of
290
pb
-
1
. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of
Q
2
. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective
Q
2
-interval are also determined. Previous results of inclusive jet cross sections in the range
150
<
Q
2
<
15
,
000
GeV
2
are extended to low transverse jet momenta
5
<
P
T
jet
<
7
GeV
. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of
Q
2
, the strong coupling constant
α
s
(
M
Z
)
is determined in next-to-leading order.
Journal Article
Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA
The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at
s
=
319
GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of 351
pb
-
1
. Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in hadronic collisions; this paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum-transfer
Q
2
>
150
GeV
2
and inelasticity
0.2
<
y
<
0.7
. We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.
Journal Article
Automated identification and classification of internal defects in composite structures using computed tomography and 3D wavelet analysis
The necessity of detection and identification of damages in structural elements intensifies the development of non-destructive testing (NDT) methods and techniques suitable for different composite materials and sensitive to particular types of damages. One of the most sensitive and accurate methods is the computed tomography (CT), which has already found a wide application in medical diagnostics and materials testing. However, there are some difficulties during testing of composite materials, whose internal structure is often quite complex. Other difficulties of application of CT are related to correct identification of diverse composite-specific defects. The following study presents the method of identification and classification of internal defects of polymeric composite structures after the water-jet cutting based on CT scanning and 3D wavelet analysis. The application of wavelet transform allows extracting meaningful information about the size of the defect, their locations and orientations and reducing the measurement noise. An applied classification procedure is based on the analysis of geometric properties of identified defects and the magnitudes of detail coefficients resulted from the wavelet transform. Proposed method could find an application both in quality control of composite components as well as their NDT during operation.
Journal Article
Measurement of exclusive π+π- and ρ0 meson photoproduction at HERA
Exclusive photoproduction of
ρ
0
(
770
)
mesons is studied using the H1 detector at the
ep
collider HERA. A sample of about 900,000 events is used to measure single- and double-differential cross sections for the reaction
γ
p
→
π
+
π
-
Y
. Reactions where the proton stays intact (
m
Y
=
m
p
) are statistically separated from those where the proton dissociates to a low-mass hadronic system (
m
p
<
m
Y
<
10
GeV
). The double-differential cross sections are measured as a function of the invariant mass
m
π
π
of the decay pions and the squared 4-momentum transfer
t
at the proton vertex. The measurements are presented in various bins of the photon–proton collision energy
W
γ
p
. The phase space restrictions are
0.5
≤
m
π
π
≤
2.2
GeV
,
|
t
|
≤
1.5
GeV
2
, and
20
≤
W
γ
p
≤
80
GeV
. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the
m
π
π
dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the
ρ
0
(
770
)
meson mass and width at
m
ρ
=
770.8
-
2.7
+
2.6
(
tot.
)
MeV
and
Γ
ρ
=
151.3
-
3.6
+
2.7
(
tot.
)
MeV
, respectively. The model is used to extract the
ρ
0
(
770
)
contribution to the
π
+
π
-
cross sections and measure it as a function of
t
and
W
γ
p
. In a Regge asymptotic limit in which one Regge trajectory
α
(
t
)
dominates, the intercept
α
(
t
=
0
)
=
1.0654
-
0.0067
+
0.0098
(
tot.
)
and the slope
α
′
(
t
=
0
)
=
0.233
-
0.074
+
0.067
(
tot.
)
GeV
-
2
of the
t
dependence are extracted for the case
m
Y
=
m
p
.
Journal Article