H1 Data Research Articles

Probing gluon GTMDs of the proton in deep inelastic diffractive dijet production at HERA

We calculate several differential distributions for diffractive dijets production in ep→e′jet jetp in the perturbative QCD dipole approach using off diagonal unintegrated gluon distributions (generalized transverse momentum dependent distributions, GTMDs). Different models from the literature are used. We concentrate on the contribution from exclusive qq¯ dijets. Results of our calculations are compared to H1 and ZEUS data, including specific experimental cuts in our calculations. In general, except for one GTMD, our results are below the HERA data. The considered mechanism is expected to gives a sizeable contribution to the ZEUS data, while it is negligible in the kinematics of the H1 measurement. This is in contrast to recent results from the literature where the normalization was adjusted to some selected distributions of the H1 collaboration and no agreement with other observables was checked. The ZEUS data provide stricter limitations on the GTMDs than the H1 data. We conclude, based on comparison to different observables, that the calculated cross sections are only a small fraction of the measured ones which contain probably also processes with pomeron remnant. Alternatively one could try to explain the experimental data by inclusion of qq¯g component of the photon wave function. We present also azimuthal correlations between the sum and the difference of dijet transverse momenta. The cuts on transverse momenta of jets generate corresponding azimuthal correlations that can be misidentified as due to elliptic gluon distributions. Published by the American Physical Society 2024

Exclusive diffractive J/ψ and ψ(2S) production in dipole model using a holographic AdS/QCD light-front wavefunction with longitudinal confinement

We use anti-de Sitter/quantum chromodynamics based holographic light-front wavefunction (LFWF) for vector meson, in conjunction with the dipole model to investigate the cross sections data for the diffractive and exclusive J/ψ and ψ(2S) production. We confront the experimental data using a new explicit form of the holographic LFWF, where the longitudinal confinement dynamics in the light-front Schrödinger equation is captured by the ’t Hooft equation of (1+1)-dim, in large Nc approximation, in addition to the transverse confinement dynamics governed by the confining mass scale parameter κ in vector mesons. We obtain the LFWF parameters from fitting to the exclusive J/ψ electroproduction data from the electron-proton collision at the Hadron Electron Ring Accelerator collider for mc=1.27 GeV. Our results suggest that the dipole model together with holographic meson LFWFs with longitudinal confinement is able to give a successful description for differential scattering cross section for exclusive J/ψ electroproduction for H1 and ZEUS data. We also predict the rapidity distributions of differential scattering cross section and total photoproduction of J/ψ and ψ(2S) states in proton-proton ultraperipheral collisions (UPCs) at center of mass energy s=7,13 TeV. Using the minimum set of parameters, our predictions for the UPCs are in good agreement with the recent experimental observations of UPCs at ALICE and LHCb Collaborations. Published by the American Physical Society 2024

Probing the Onset of Maximal Entanglement inside the Proton in Diffractive Deep Inelastic Scattering.

It has been proposed that at small Bjorken x, or equivalently at high energy, hadrons represent maximally entangled states of quarks and gluons. This conjecture is in accord with experimental data from the electron-proton collider HERA at the smallest accessible x. In this Letter, we propose to study the onset of the maximal entanglement inside the proton using diffractive deep inelastic scattering. It is shown that the data collected by the H1 Collaboration at HERA allow one to probe the transition to the maximal entanglement regime. By relating the entanglement entropy to the entropy of final-state hadrons, we find a good agreement with the H1 data using both the exact entropy formula as well as its asymptotic expansion which indicates the presence of a nearly maximally entangled state. Finally, future opportunities at the Electron Ion Collider are discussed.

Maximally entangled proton and charged hadron multiplicity in Deep Inelastic Scattering

We study the proposal by Kharzeev–Levin to determine entanglement entropy in Deep Inelastic Scattering (DIS) from parton distribution functions (PDFs) and to relate the former to the entropy of final state hadrons. We find several uncertainties in the current comparison to data, in particular the overall normalization, the relation between charged versus total hadron multiplicity in the comparison to experimental results as well as different methods to determine the number of partons in Deep Inelastic Scattering. We further provide a comparison to data based on leading order HERA PDF as well as PDFs obtained from an unintegrated gluon distribution subject to next-to-leading order Balitsky–Fadin–Kuraev–Lipatov and Balitsky–Kovchegov evolution. Within uncertainties we find good agreement with H1 data. We provide also predictions for entropy at lower photon virtualities, where non-linear QCD dynamics is expected to become relevant.

Al-Muqaranah Baina Natijah Ta’lim ‘Ibr al-Internet wa Ta’lim al-Liqa’i fi Ta’lim al-Lughah al-‘Arabiyyah laday al-Thullab al-Tsanawi

It is no wonder that learning outcome is very important to measure the success of the education activities that are implemented. But how if education that is usually implemented with offline education, is replaced by online education because of the Covid-19 pandemic. Based on that, The objectives of this research are to find out the difference between the result of online education and offline learning in teaching Arabic among students at the Islamic Intermediate School “Darus Sholah”. The methodology of this research is the quantitative approach, and the method of collecting observation and documentation consists of data analysis by descriptive quantitative analysis with induction statistics by type, non-parametric statistics. The results of the research there is no comparison between the result of online education and offline education in teaching Arabic among students at the Islamic Intermediate School “Darus Sholah”. In conclusion, the result of the analysis hypothesis shows that 0.09 has more value than 0.05 (0.05 < 0.09) µ1 = µ2 H0, H0 is accepted and H1 data is rejected. This means that the data showed is accepted.

Evidence for the maximally entangled low x proton in Deep Inelastic Scattering from H1 data

We investigate the proposal by Kharzeev and Levin of a maximally entangled proton wave function in Deep Inelastic Scattering at low x and the proposed relation between parton number and final state hadron multiplicity. Contrary to the original formulation we determine partonic entropy from the sum of gluon and quark distribution functions at low x, which we obtain from an unintegrated gluon distribution subject to next-to-leading order Balitsky–Fadin–Kuraev–Lipatov evolution. We find for this framework very good agreement with H1 data. We furthermore provide a comparison based on NNPDF parton distribution functions at both next-to-next-to-leading order and next-to-next-to-leading with small x resummation, where the latter provides an acceptable description of data.

Higher order approximations to the longitudinal structure function FL from the parametrization of F2 based on the Laplace transformation

We describe the determination of the longitudinal structure function $F_{L}$ at NLO and NNLO approximations, using Laplace transform techniques, into the parametrization of $F_{2}(x,Q^{2})$ and its derivative with respect to $\ln{Q^{2}}$ at low values of the Bjorken variable $x$. The obtained results are comparable with others by considering the effect of the charm quark mass to the longitudinal structure function, which leads to rescaling variable for $n_{f}=4$. Numerical calculations and comparison with H1 data demonstrate that the suggested method provides reliable $F_{L}(x,Q^{2})$ at small $x$ in a wide range of $Q^{2}$ values and can be applied as well in analyses of ultra-high energy processes with cosmic neutrinos. The obtained longitudinal structure functions with and without the LHeC simulated uncertainties [CERN-ACC-Note-2020-0002, LHeC Collaboration and FCC-he Study Group, P. Agostini et al., J. Phys. G: Nucl. Part. Phys. {\bf48}, 110501(2021).] are compared with the H1 Collaboration data [Eur.Phys.J.C{\bf74}, 2814(2014) and Eur.Phys.J.C{\bf71}, 1579 (2011)] and with the results from CT18 [Phys.Rev.D{\bf103}, 014013(2021)] parametrization model at NLO and NNLO approximations.

Effect of the Parameterization of the Distribution Functions on the Longitudinal Structure Function at Small x

I use a direct method to extract the longitudinal structure function in the next-to-leading order approximation with respect to the number of active flavor from the parametrization of parton distributions. The contribution of charm and bottom quarks corresponding to the gluon distributions (i.e., $G_{n_{f}=3}(x,Q^{2})$ and $G_{n_{f}=5}(x,Q^{2})$) is considered. I compare the obtained longitudinal structure function at $n_{f}=4$ with the H1 data [Eur.Phys.J.C{\bf74}, 2814(2014) and Eur.Phys.J.C{\bf71}, 1579 (2011)] and the result L.P.Kaptari et al.[ Phys.Rev.D{\bf 99}, 096019(2019)] which is based on the Mellin transforms. These calculations compared with the results from CT18 [Phys.Rev.D103, 014013(2021)] parametrization model. The nonlinear effects on the gluon distribution improve the behavior of the longitudinal structure function in comparison with the H1 data and CT18 at low values of $Q^{2}$.

Color dipole model bounds with the gluon-gluon recombination correction

We present nonlinear (NL) and higher twist (HT) corrections to the color dipole model (CDM) bounds at low values of $x$ and $Q^{2}$ using the parameterization method. Consistency between the bounds at this region describe that a transition from the linear to the nonlinear behavior is dependence on the behavior of the gluon distribution function. The parameters in the color dipole model are comparable with the color dipole bounds at low values of $Q^{2}$. Consequently, the obtained reduced cross sections at low and moderate $Q^{2}$ values due to the NL+HT effects show a good agreement with the H1 data.

Deep Learning for Gravitational-Wave Data Analysis: A Resampling White-Box Approach.

In this work, we apply Convolutional Neural Networks (CNNs) to detect gravitational wave (GW) signals of compact binary coalescences, using single-interferometer data from real LIGO detectors. Here, we adopted a resampling white-box approach to advance towards a statistical understanding of uncertainties intrinsic to CNNs in GW data analysis. We used Morlet wavelets to convert strain time series to time-frequency images. Moreover, we only worked with data of non-Gaussian noise and hardware injections, removing freedom to set signal-to-noise ratio (SNR) values in GW templates by hand, in order to reproduce more realistic experimental conditions. After hyperparameter adjustments, we found that resampling through repeated k-fold cross-validation smooths the stochasticity of mini-batch stochastic gradient descent present in accuracy perturbations by a factor of . CNNs are quite precise to detect noise, for H1 data and for L1 data; but, not sensitive enough to recall GW signals, for H1 data and for L1 data—although recall values are dependent on expected SNR. Our predictions are transparently understood by exploring tthe distribution of probabilistic scores outputted by the softmax layer, and they are strengthened by a receiving operating characteristic analysis and a paired-sample t-test to compare with a random classifier.

An evaluation of the proton structure functions F2 and FL at small x

We describe the determination of the DIS structure functions F2 and FL by using the singlet Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and Altarelli-Martinelli equations at small values of x. The determination of the longitudinal structure function is presented as a parameterization of F2(x,Q2) and its derivative. Analytical expressions for σr(x,Q2) in terms of the effective parameters of the parameterization of F2(x,Q2) and FL(x,Q2) are presented. This analysis is enriched by including the higher-twist effects in calculation of the reduced cross sections which is important at low-x and low-Q2 regions. Numerical calculations and comparison with H1 data demonstrate that the suggested method provides reliable FL(x,Q2) and σr(x,Q2) at low x in a wide range of the low absolute four-momentum transfers squared (1.5 GeV2<Q2<120 GeV2) at moderate and high inelasticity. Expanding the method to low and ultra low values of x can be considered in the process analysis of new colliders. We compare the obtained longitudinal structure function with respect to the LHeC simulated uncertainties (Agostini et al. (2020) [4]) with the results from CT18 (Hou et al. (2021) [54]) parametrization model.

Preservation through modernisation: The software of the H1 experiment at HERA

The lepton–proton collisions produced at the HERA collider represent a unique high energy physics data set. A number of years after the end of collisions, the data collected by the H1 experiment, as well as the simulated events and all software needed for reconstruction, simulation and data analysis, were migrated into a preserved operational mode at DESY. A recent modernisation of the H1 software architecture has been performed, which will not only facilitate on going and future data analysis efforts with the new inclusion of modern analysis tools, but also ensure the long-term availability of the H1 data and associated software. The present status of the H1 software stack, the data, simulations and the currently supported computing platforms for data analysis activities are discussed.

The behavior of the structure function by using the effective exponent at low x

An analytical solution of the QCD evolution equations for the singlet and gluon distribution is presented. We decouple DGLAP evolution equations into the initial conditions by using a Laplace transform method at $N^{n}LO$ analysis. The relationship between the nonlinear behavior and color dipole model is considered based on an effective exponent behavior at low-$x$ values. We obtain the effective exponent at NLO analysis from the decoupled behavior of the distribution functions. The proton structure function compared with H1 data from the inclusive structure function $F_{2}(x,Q^{2})$ for $x {\leq}~ 10^{-2}$ and $5 {\leq} Q^{2} {\leq} 250~GeV^{2}$.

Probing the saturation effects in the inclusives observables at the future ep/eA collider at the LHC

In this paper we investigate the impact of the saturation effects in the inclusive observables that will be measured in the future Large Hadron Electron Collider (LHeC). The reduced total and heavy quark cross sections are estimated considering the more recent phenomenological models for the dipole-proton scattering amplitude, which are based on the Color Glass Condensate formalism and are able to describe the inclusive and exclusive ep HERA data. We compare, for the first time, the predictions of these models with the recent combined H1 and ZEUS data for the charm and bottom production, and present predictions for the reduced cross sections considering the kinematical range that will be probed in ep collisions at the LHeC. Moreover, we estimate the magnitude of the saturation effects for the nuclear, longitudinal and charm structure functions in the case of eA collisions at the LHeC. Our results indicate that the future experimental data will be useful to discriminate between the different models for the nonlinear QCD dynamics.

Sivers effect in inelastic J/ψ photoproduction in ep↑ collision in color octet model

The prediction of single-spin asymmetry in inelastic photoproduction of $J/\psi$ in $ep^\uparrow$ collision is presented. At next-to-leading order, the dominating process is photon-gluon fusion, $\gamma+g\rightarrow J/\psi+g$ for the production of $J/\psi$ in $e+p^\uparrow\rightarrow J/\psi+X$, which directly probes the gluon Sivers function. Using the non-relativistic QCD based color octet model, the color octet states $\leftidx{^{3}}{S}{_1}^{(8)}$, $\leftidx{^{1}}{S}{_0}^{(8)}$ and $\leftidx{^{3}}{P}{_{J(0,1,2)}}^{(8)}$ contribution to $J/\psi$ production is calculated. Sizable asymmetry is estimated as a function of transverse momentum $P_T$ and energy fraction $z$ of $J/\psi$ in the range $0<P_T\leq 1$ GeV and $0.3<z\leq 0.9$. The unpolarized differential cross section of inelastic $J/\psi$ photoproduction is found to be in good agreement with H1 and ZEUS data.

Impact of LHCb data on the PDFs from H1 and ZEUS Collaborations

This Next-to-Leading Order (NLO) Quantum Chromo Dynamics (QCD) analysis attempts to investigate the impact of LHCb charm and beauty production data in pp collisions at s=7TeV on the Parton Distribution Functions (PDFs) extracted from H1 and ZEUS collaboration data sets. We show adding the LHCb charm and beauty production data on the H1 and ZEUS combined data sets reduces the uncertainty bands of partonic distributions and improve the relative fit-quality up to 4.0 %.

Time-resolved 2D concentration maps in flowing suspensions using X-ray

In this paper, we introduce a new technique based on X-ray radiography with high temporal (O(0.1 s)) and spatial (O(10 μm)) resolutions to study fast suspension flows regardless of optical access. We benefit from the axial symmetry of our flow configuration, a wide gap Couette setup, to extract a 3D solid volume fraction field from a single X-ray projection image. We propose a mathematical algorithm based on the inversion of Abel transform in conjunction with H1 regularization and data denoising to measure the solid volume fraction field in suspensions in a fraction of a second. We show that the results are in excellent agreement with those obtained from micro Computed Tomography (CT scan) in one hour. This significant reduction in the data acquisition time opens a new avenue in the field of suspensions. As a proof of concept, we study the kinetics of shear-induced migration for suspensions of particles in both Newtonian and yield stress suspending fluids. The latter experiments include two different conditions: With and without a plug region. In both cases, we are able to capture in detail the kinetics of migration. In the presence of a plug region, we manage to accurately describe the particle accumulation at the interface between the sheared and the static regions. Remarkably, even in the absence of sedimentation, the concentration profiles show a complex 2D structure, with no z-invariant region, which illustrates the strong impact of top and bottom boundary effects on migration. We also show the importance of boundary effects on the shear induced migration of particles in a Newtonian suspending fluid. This further shows the necessity of developing techniques that give access to the full spatial concentration field, as the one we present here.

Effects of next-to-leading order DGLAP evolution on generalized parton distributions of the proton and deeply virtual Compton scattering at high energy

We studied the effects of NLO Q^2 evolution of generalized parton distributions (GPDs) using the aligned-jet model for the singlet quark and gluon GPDs at an initial evolution scale. We found that the skewness ratio for quarks is a slow logarithmic function of Q^2, reaching r^mathrm{S}=1.5{-}2 at Q^2=100 GeV^2 and r^mathrm{g} approx 1 for gluons in a wide range of Q^2. Using the resulting GPDs, we calculated the DVCS cross section on the proton in NLO pQCD and found that this model in conjunction with modern parameterizations of proton PDFs (CJ15 and CT14) provides a good description of the available H1 and ZEUS data in a wide kinematic range.

Q 2-evolution of parton densities at small x values. Charm contribution in the combined H1 and ZEUS F 2 data

The Bessel-inspired behavior of parton densities at small x, obtained in the case of the flat initial conditions for DGLAP evolution equations, is used in the fixed flavor scheme to analyze precise H1 and ZEUS combined data on the structure function F 2.

The role of different schemes in the QCD analysis and determination of the strong coupling

In this article, we present a Next-to-Leading Order (NLO) QCD analysis to study the role and influence of different schemes on simultaneous determination of the Parton Distribution Functions (PDFs) and strong coupling, αs(MZ2). We perform our analysis based on three different data sets, HERA I and II combined data, H1-ZEUS charm combined data, and H1 and ZEUS beauty production cross sections data, in two different Thorne–Roberts (TR or RT) and Thorne–Roberts Optimal (RT OPT) schemes. We show in going from RT scheme to RT OPT scheme, in addition of reduction the uncertainty of some PDFs, specially for the gluon distribution, we get ∼0.4% and ∼0.7% improvement in the fit quality and ∼0.9% and ∼1.6% improvement for the strong coupling, αs(MZ2), without and with heavy flavor contributions, respectively.