A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised
e
±
p
scattering at HERA during the ...period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared,
Q
2
, and in Bjorken
x
. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
The exclusive photoproduction reaction γp→ϒp has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb−1. The measurement covers the kinematic range ...60<W<220 GeV and Q2<1 GeV2, where W is the photon–proton centre-of-mass energy and Q2 is the photon virtuality. These results, which represent the analysis of the full ZEUS data sample for this channel, are compared to predictions based on perturbative QCD.
An overwhelming number of theoretical predictions for hadron colliders require parton distribution functions (PDFs), which are an important ingredient of theory infrastructure for the next generation ...of high-energy experiments. Here this whitepaper summarizes the status and future prospects for determination of high-precision PDFs applicable in a wide range of energies and experiments, in particular in precision tests of the Standard Model and in new physics searches at the high-luminosity Large Hadron Collider and Electron–Ion Collider. We discuss the envisioned advancements in experimental measurements, QCD theory, global analysis methodology, and computing that are necessary to bring unpolarized PDFs in the nucleon to the N2LO and N3LO accuracy in the QCD coupling strength. Special attention is given to the new tasks that emerge in the era of the precision PDF analysis, such as those focusing on the robust control of systematic factors both in experimental measurements and theoretical computations. Various synergies between experimental and theoretical studies of the hadron structure are explored, including opportunities for studying PDFs for nuclear and meson targets, PDFs with electroweak contributions or dependence on the transverse momentum, for incisive comparisons between phenomenological models for the PDFs and computations on discrete lattice, and for cross-fertilization with machine learning/AI approaches.
The cross-section for deeply virtual Compton scattering in the reaction ep→eγp has been measured with the ZEUS detector at HERA using integrated luminosities of 95.0 pb−1 of e+p and 16.7 pb−1 of e−p ...collisions. Differential cross-sections are presented as a function of the exchanged-photon virtuality, Q2, and the centre-of-mass energy, W, of the γ∗p system in the region 5<Q2<100 GeV2 and 40<W<140 GeV. The measured cross-sections rise steeply with increasing W. The measurements are compared to QCD-based calculations.
Aim
The worldwide increase in obesity and type 2 diabetes (T2D) represents a major health challenge. Chronically altered lipids induced by obesity further promote the development of T2D, and the ...accumulation of toxic lipid metabolites in serum and peripheral organs may contribute to the diabetic phenotype.
Methods
To better understand the complex metabolic pattern of lean and obese T2D and non‐T2D individuals, we analysed the lipid profile of human serum, skeletal muscle and visceral adipose tissue of two cohorts by systematic mass spectrometry‐based lipid analysis.
Results
Lipid homeostasis was strongly altered in a disease‐ and tissue‐specific manner, allowing us to define T2D signatures associated with obesity from those that were obesity independent. Lipid changes encompassed lyso‐, diacyl‐ and ether‐phospholipids. Moreover, strong changes in sphingolipids included cytotoxic 1‐deoxyceramide accumulation in a disease‐specific manner in serum and visceral adipose tissue. The high amounts of non‐canonical 1‐deoxyceramide present in human adipose tissue most likely come from cell‐autonomous synthesis because 1‐deoxyceramide production increased upon differentiation to adipocytes in mouse cell culture experiments.
Conclusion
Taken together, the observed lipidome changes in obesity and T2D will facilitate the identification of T2D patient subgroups and represent an important step towards personalized medicine in diabetes.
Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320 pb−1. Measurements were made in the isolated-photon ...transverse-energy and pseudorapidity ranges 4<ETγ<15 GeV and −0.7<ηγ<0.9 for exchanged photon virtualities, Q2, in the range 10<Q2<350 GeV2 and for invariant masses of the hadronic system WX>5 GeV. Differential cross sections are presented for inclusive isolated photon production as functions of Q2, x, ETγ and ηγ. Leading-logarithm parton-shower Monte Carlo simulations and perturbative QCD predictions give a reasonable description of the data over most of the kinematic range.
For the first time, differential inclusive-jet cross sections have been measured in neutral current deep inelastic ep scattering using the anti-kT and SIScone algorithms. The measurements were made ...for boson virtualities Q2>125 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 82 pb−1 and the jets were identified in the Breit frame. The performance and suitability of the jet algorithms for their use in hadron-like reactions were investigated by comparing the measurements to those performed with the kT algorithm. Next-to-leading-order QCD calculations give a good description of the measurements. Measurements of the ratios of cross sections using different jet algorithms are also presented; the measured ratios are well described by calculations including up to O(αs3) terms. Values of αs(MZ) were extracted from the data; the results are compatible with and have similar precision to the value extracted from the kT analysis.
Single- and double-differential inclusive dijet cross sections in neutral current deep inelastic
ep
scattering have been measured with the ZEUS detector using an integrated luminosity of 374 pb
−1
. ...The measurement was performed at large values of the photon virtuality,
Q
2
, between 125 and 20 000 GeV
2
. The jets were reconstructed with the
k
T
cluster algorithm in the Breit reference frame and selected by requiring their transverse energies in the Breit frame,
, to be larger than 8 GeV. In addition, the invariant mass of the dijet system,
, was required to be greater than 20 GeV. The cross sections are described by the predictions of next-to-leading-order QCD.
Injection therapies play a major role in the treatment of lower back pain and are to date performed mainly under CT- or fluoroscopic guidance. We conducted this study to evaluate the accuracy, time ...savings, radiation doses, and pain relief of US-guided pararadicular injections versus CT-controlled interventions in the lumbar spine in a prospective randomized clinical trial.
Forty adult patients were consecutively enrolled and assigned to a US or CT group. US-guided pararadicular injections were performed on a standard US device by using a broadband curved-array transducer (9-4 or 5-1 MHz). In the in-plane technique, the needle was advanced through the respective segmental intertransverse ligament. The needle tip position was verified by CT. The CT-guided approaches were performed under standardized procedures by using the CT-positioning laser function.
The accuracy of US-guided interventions was 90%. The mean time to final needle placement in the US group was 4.0 ± 1.8 minutes, and in the CT group, 7.6 ± 2.1 minutes. The mean radiation doses, including CT confirmation for study purposes only, were 20.3 ± 9.0 mGy cm for the US group and 42.6 ± 36.1 mGy cm for the CT group. Both groups showed the same significant pain relief (P < .05) without relevant "intermethodic" differences of pain relief (P > .05).
US-guided pararadicular injections show a therapeutic effect similar to that in the time-consuming, expensive, ionizing CT or fluoroscopically guided pararadicular injections and result in a significant reduction of procedure time expenditure and avoidance of radiation.
The production of charm and beauty quarks in
ep
interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange
Q
2
>20 GeV
2
, using an integrated luminosity of ...126 pb
−1
. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta
and pseudorapidities −1.6<
η
μ
<2.3, as a function of
,
η
μ
,
Q
2
and Bjorken
x
. The charm and beauty contributions to the proton structure function
F
2
were also extracted. The results agree with previous measurements based on independent techniques and are well described by QCD predictions.
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