Technologies based on magnetic sensors with high sensitivity such as magneto-resistance (AMR, GMR), fluxgate or squid sensors have demonstrated their capability to improve the performances of the ...classical eddy current (EC) probes.
In this paper, a new kind of magnetic sensor based on giant magneto-impedance (GMI) effect has been evaluated. This sensor combines good sensitivity performances at low frequencies and small size. The design of a probe using this new technology has been optimized with fast semi-analytical models. The performances of this GMI based probe have then been successfully evaluated on a 304
L stainless steel mock up for the detection of embedded flaws.
A new QCD analysis of deep inelastic scattering (DIS) data is presented. All available neutrino and antineutrino cross sections are reanalyzed and included in the fit, along with charged-lepton DIS ...and Drell–Yan data. A massive factorization scheme is used to describe the charm component of the structure functions. Next-to-leading-order parton distribution functions are provided. In particular, the strange-sea density is determined with a higher accuracy with respect to other global fits.
A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current $e^{\pm}p$ scattering for zero ...beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb$^{-1}$ and span six orders of magnitude in negative four-momentum-transfer squared, $Q^2$, and Bjorken $x$. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in $\alpha_s(M_Z)=0.1183 \pm 0.0009 {\rm(exp)} \pm 0.0005{\rm (model/parameterisation)} \pm 0.0012{\rm (hadronisation)} ^{+0.0037}_{-0.0030}{\rm (scale)}$. An extraction of $xF_3^{\gamma Z}$ and results on electroweak unification and scaling violations are also presented.
Cross sections for elastic and proton-dissociative photoproduction of
J
/
ψ
mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at
ep
...centre-of-mass energies
and
, corresponding to integrated luminosities of
and
, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25<
W
γp
<110 GeV. Differential cross sections d
σ
/d
t
, where
t
is the squared four-momentum transfer at the proton vertex, are measured in the range |
t
|<1.2 GeV
2
for the elastic process and |
t
|<8 GeV
2
for proton dissociation. The results are compared to other measurements. The
W
γp
and
t
-dependences are parametrised using phenomenological fits.
A method to derive the ABCD matrices for reflection and refraction for any diopter under arbitrary incident angle is developed. The result is benchmarked on a commercial software for an optical ...system compound of two cylindrical lenses. It is used to simulate the general astigmatism and calculate the resulting Orbital Angular Momentum of a laser beam that propagate through a pair of cylindrical lenses. It more generally useful to ease and simplify such kind of simulations in any optical system by avoiding use of complicated commercial softwares.
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.
The Breit frame provides a natural frame to analyze lepton–proton scattering events. In this reference frame, the parton model hard interactions between a quark and an exchanged boson defines the ...coordinate system such that the struck quark is back-scattered along the virtual photon momentum direction. In Quantum Chromodynamics (QCD), higher order perturbative or non-perturbative effects can change this picture drastically. As Bjorken-
x
decreases below one half, a rather peculiar event signature is predicted with increasing probability, where no radiation is present in one of the two Breit-frame hemispheres and all emissions are to be found in the other hemisphere. At higher orders in
α
s
or in the presence of soft QCD effects, predictions of the rate of these events are far from trivial, and that motivates measurements with real data. We report on the first observation of the empty current hemisphere events in electron–proton collisions at the HERA collider using data recorded with the H1 detector at a center-of-mass energy of 319 GeV. The fraction of inclusive neutral-current DIS events with an empty hemisphere is found to be
0.0112
±
3.9
%
stat
±
4.5
%
syst
±
1.6
%
mod
in the selected kinematic region of
150
<
Q
2
<
1500
GeV
2
and inelasticity
0.14
<
y
<
0.7
. The data sample corresponds to an integrated luminosity of 351.1 pb
-
1
, sufficient to enable differential cross section measurements of these events. The results show an enhanced discriminating power at lower Bjorken-
x
among different Monte Carlo event generator predictions.
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