Plots from Rivet analyses

Charged particle production in deep-inelastic ep scattering at H1 (H1_2013_I1217865)

Inspire | HepData | Eur.Phys.J. C73 (2013) 2406, | arXiv:1302.1321

Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q2 < 100 GeV2 and small values of Bjorken-x, 10**-2 < x < 10**-2. The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity eta* and transverse momentum pT* in the range 0 <eta* <5 and 0 < pT* < 10 GeV in bins of x and Q2.

Measurement of Event Shape Variables in Deep-Inelastic Scattering at HERA (H1_2006_I699835)

Inspire | HepData | Eur.Phys.J.C 46 (2006) 343-356 | DOI:10.1140/epjc/s2006-02493-x | arXiv:hep-ex/0512014v1

Deep-inelastic ep scattering data taken with the H1 detector at HERA and corresponding to an integrated luminosity of $106 pb^{-1}$ are used to study the differential distributions of event shape variables. These include thrust, jet broadening, jet mass and the C-parameter. The four-momentum transfer Q is taken to be the relevant energy scale and ranges between 14 GeV and 200 GeV.

Measurement of beauty production at HERA using events with muons and jets (H1) (H1_2005_I676166)

Inspire | HepData | Eur.Phys.J.C 41 (2005) 453 | DOI:10.1140/epjc/s2005-02267-0 | arXiv:hep-ex/0502010 | DESY-05-004

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 b-flavoured hadrons are exploited to identify events containing beauty quarks. Differential cross sections are measured in photoproduction, with photon virtualities $Q^2 < 1$ GeV$^2$, and in deep inelastic scattering, where $2 < Q^2 < 100$ GeV$^2$.

Combined H1/ZEUS $D^*$ production cross-sections in DIS (HERA_2015_I1353667)

Inspire | HepData | JHEP 1509 (2015) 149 | DOI:10.1007/JHEP09(2015)149 | DESY-15-037 | arxiv:1503.06042 | http://www-h1.desy.de/publications/htmlsplit/DESY-15-037.long.poster.html

H1 and ZEUS combined differential cross-sections for inclusive $D^{*\pm}$ production in deep-inelastic $ep$ scattering at HERA. The cross-sections are combined in the common visible phase-space region of photon virtuality $Q^2 > 5 \text{GeV}^2$, electron inelasticity $0.02 < y < 0.7$, and the $D^{*\pm}$ meson's transverse momentum $p_T(D^*) > 1.5 \text{GeV}$ and pseudorapidity $|\eta(D^*)| < 1.5$. The combination procedure takes into account all correlations. Double-differential cross sections $d2\sigma/dQ^2 dy$ are combined with earlier $D^{∗\pm}$ data, extending the kinematic range down to $Q^2 > 1.5 \text{GeV}^2$.

Scaled momentum distributions for $K^0_S$ and $\Lambda/\bar{\Lambda}$ in DIS at HERA (ZEUS_2011_I945935)

Inspire | HepData | JHEP 1203 (2012) 020 | DOI: 10.1007/JHEP03(2012)020 | DESY-11-205 | arXiv:1111.3526

Scaled momentum distributions for the strange hadrons K0s and Lambda/bar Lambda were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of $330 pb^{-1}$. The evolution of these distributions with the photon virtuality, $Q^2$, was studied in the kinematic region $10<Q^2<40000 GeV^2$ and $0.001<x<0.75$, where $x$ is the Bjorken scaling variable. Clear scaling violations are observed. Predictions based on different approaches to fragmentation were compared to the measurements. Leading-logarithm parton-shower Monte Carlo calculations interfaced to the Lund string fragmentation model describe the data reasonably well in the whole range measured. Next-to-leading-order QCD calculations based on fragmentation functions, FFs, extracted from $e^+e^-$ data alone, fail to describe the measurements. The calculations based on FFs extracted from a global analysis including $e^+e^-$, $ep$ and $pp$ data give an improved description. The measurements presented in this paper have the potential to further constrain the FFs of quarks, anti-quarks and gluons yielding $K^0_{S}$ and $\Lambda/\bar{ \Lambda}$ strange hadrons.

ZEUS dijet cross sections in NC DIS (ZEUS_2010_I875006)

Inspire | HepData | Eur.Phys.J.C70:965-982,2010 | doi:10.1140/epjc/s10052-010-1504-2 | arXiv:1010.6167v1

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$_T^{B,jet}$, 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. The cross sections are described by the predictions of next-to-leading-order QCD.

Measurement of $D^{\pm}$ and $D^0$ production in deep inelastic scattering using a lifetime tag at HERA (ZEUS_2008_I810112)

Inspire | HepData | Eur.Phys.J.C 63 (2009) 171-188 | DOI:10.1140/epjc/s10052-009-1088-x | arXiv:0812.3775

The production of $D^{\pm}$ and $D^{0}$ mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of $133.6 pb^{-1}$. The measurements cover the kinematic range $5 < Q^2 < 1000 GeV^2$, $0.02 < y < 0.7$, $1.5 < p_T^D < 15 GeV$ and $\eta^D < 1.6$. Combinatorial background to the D meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, $F_2^c\bar{c}$, to the proton structure function, $F_2$.