Rivet, RivetHZTool and HERA -- A validation effort for coding HERA measurements for Rivet

During the DESY summer student program 2021, young scientists from more than 13 different countries worked together, connecting from remote, to provide computer codes within the Rivet framework for 18 HERA measurements. Most of these measurements were originally available within the HZTool package, but no longer accessible for modern analysis packages such as Rivet. The temporary RivetHZTool interface was used to validate most of the new Rivet plugins. Abstract (cited ”Charged particle production has been measured in Deep Inelastic Scattering (DIS) events using the ZEUS detector over a large range of Q 2 from 10 to 1280 GeV 2 . The evolution with Q of the charged multiplicity and scaled momentum has been investigated in the current fragmentation region of the Breit frame.” The results kinematic particle Abstract (cited ”Deep inelastic scattering (DIS) events, selected from 1993 data taken by the H1 experiment at HERA, are studied in the Breit frame of reference. It is shown that certain aspects of the quarks emerging from within the proton in ep interactions are essentially the same as those of quarks pair-created from the vacuum in e + e − annihila-tion.” for kinematic range. and parton shower: initial state, final state any parton shower. Abstract (cited from Ref. [21]): ”This paper presents measurements of K 0 and Λ production in neutral current, deep inelastic scattering of 26.7 GeV electrons and 820 GeV protons in the kinematic range 10 < Q 2 < 640 GeV 2 , 0 . 0003 < x < 0 . 01 , and y > 0 . 04 . Average multiplicities for K 0 and Λ production are determined for transverse momenta p T > 0 . 5 GeV and pseudorapidities | η | < 1 . 3 . The production properties of K 0 ’s in events with and without a large rapidity gap with respect to the proton direction are compared. The ratio of neutral K 0 ’s to charged particles per event in the measured kinematic range is, within the present statistics, the same in both samples.” The results obtained reconstruction. observed results on inclusive D 0 and D ∗ production in deep inelastic ep scattering reported using data collected by the H1 experiment at Abstract ”Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic ep scattering have been measured over a large kinematical region. The evolution with W and Q 2 of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation Abstract ”Transverse momentum spectra of charged particles pro-duced in deep inelastic scattering are measured as a function of the kinematic variables x B and Q 2 using the H1 detector at the ep collider HERA. The data are compared to different parton emission models, either with or without ordering of the emissions in transverse momentum. The data provide evidence for a relatively large amount of parton radiation between the current and the remnant systems.” The results of the Rivet plugin 7 are compared with those from RivetHZTool for the same kinematic range. Validation plots for the charged multiplicity as a function of the transverse momentum in the hadronic center-of-mass frame are shown in Fig. 12. Abstract (cited ”Low x deep-inelastic ep scattering data, taken in 1994 at the H1 detector at HERA, are analysed in the Breit frame of reference. ” Abstract (cited from Ref. [26]): ”The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dσ ep /dE ∗ t and dσ ep /dη ∗ , where E ∗ t and η ∗ are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q 2 < 49 GeV 2 and 0 . 3 < y < 0 . 6 . ” Abstract (cited ”With the H1 detector at the ep collider HERA, D ∗ meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q 2 > 2 GeV 2 and in photoproduction at energies around W γp ∼ 88 GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe the differential cross sections within theoretical and experimental uncertainties. ” results The MC for γg c ¯ , using 6L and HERAPDF20 as density functions Abstract (cited from ”The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron - proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time.” The results of the Rivet compared with those from RivetHZTool the Abstract (cited ”The inclusive production of D ∗± (2010) mesons in deep-inelastic scattering is studied with the H1 detector at Abstract (cited ”A measurement of the beauty production cross section in ep collisions at a centre-of-mass energy of 319 GeV is presented. The data were collected with the H1 detector at the HERA collider in the years 1999-2000. Events are selected by requiring the presence of jets and muons in the final state. Both the long lifetime and the large mass of Abstract (cited from Ref. [34]: ”The production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable ( x Bj ) and as triple differential cross sections d 3 σ/dx Bj dQ 2 dp 2 t,jet , where Q 2 is the four momentum transfer squared and p 2 t,jet is the squared transverse momentum of the forward jet. Also cross sections for events with a dijet system in addition to the forward jet are measured as a function of the rapidity separation between the forward jet and the two additional jets.” Abstract ep scattering data taken H1 detector Abstract (cited ”Inclusive D ∗ production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D ∗ meson is investigated. The analysis covers values of photon virtuality 2 < Q 2 ≤ 100 GeV 2 and of inelasticity 0 . 05 ≤ y ≤ 0 . 7 . Differential cross sections are measured as a function of Q 2 and x and of various D ∗ meson and jet observables. ” Abstract (cited ”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 20000 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, E jetT,B , to be larger than 8 GeV. In addition, the invariant mass of the dijet system, M jj , was required to be greater than 20 GeV.