A first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in deep-inelastic ep neutral current scattering at HERA. The measurement is performed in ...the range of negative squared four momentum transfer 100<Q2<8000 GeV2. The difference between the event normalised distributions of the scaled momentum, xp, for positively and negatively charged particles, measured in the current region of the Breit frame, is studied together with its evolution as a function of Q. The results are compared to Monte Carlo models at the hadron and parton levels.
The production of jets is studied in deep-inelastic e super(c)p scattering at large negative four momentum transfer squared 150<Q super(2)<15000 GeV super(2) using HERA data taken in 1999-2007, ...corresponding to an integrated luminosity of 395 pb super(− 1). Inclusive jet, 2-jet and 3-jet cross sections, normalised to the neutral current deep-inelastic scattering cross sections, are measured as functions of Q super(2), jet transverse momentum and proton momentum fraction. The measurements are well described by perturbative QCD calculations at next-to-leading order corrected for hadronisation effects. The strong coupling as determined from these measurements is (PDF).
The production of jets is studied in deep-inelastic
e
+
p
scattering at low negative four momentum transfer squared 5<
Q
2
<100 GeV
2
and at inelasticity 0.2<
y
<0.7 using data recorded by the H1 ...detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb
−1
. Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of
Q
2
and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction
ξ
. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling
α
s
.
The production of jets is studied in deep-inelastic
e
±
p
scattering at large negative four momentum transfer squared 150<
Q
2
<15000 GeV
2
using HERA data taken in 1999–2007, corresponding to an ...integrated luminosity of 395 pb
−1
. Inclusive jet, 2-jet and 3-jet cross sections, normalised to the neutral current deep-inelastic scattering cross sections, are measured as functions of
Q
2
, jet transverse momentum and proton momentum fraction. The measurements are well described by perturbative QCD calculations at next-to-leading order corrected for hadronisation effects. The strong coupling as determined from these measurements is
(PDF).
Inclusive non-diffractive photoproduction of ρ(770)0, K∗(892)0 and ϕ(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average γp centre-of-mass energy is ...210 GeV. The mesons are measured in the transverse momentum range 0.5<pT<7 GeV and the rapidity range |ylab|<1. Differential cross sections are presented as a function of transverse momentum and rapidity, and are compared to the predictions of hadroproduction models.
Inclusive non-diffractive photoproduction of rho(770)^0, K^*(892)^0 and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average \gamma p ...centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5
The production of neutral strange hadrons is investigated using deep-inelastic scattering events measured with the H1 detector at HERA. The measurements are made in the phase space defined by the ...negative four-momentum transfer squared of the photon 2<Q super(2)<100 GeV super(2) and the inelasticity 0.1<y<0.6. The K sub(s ) super(0) and $\varLambda(\bar{\varLambda})$ production cross sections and their ratios are determined. K sub(s ) super(0) production is compared to the production of charged particles in the same region of phase space. The - $\bar{\varLambda}$ asymmetry is also measured and found to be consistent with zero. Predictions of leading order Monte Carlo programs are compared to the data.
A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV^2 < Q^2 < 12 GeV^2, and low Bjorken x, 5x10^-6 < x < 0.02. The result is based ...on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q^2 and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.
A first measurement is reported of the longitudinal proton structure function FL(x,Q2) at the ep collider HERA. It is based on inclusive deep inelastic e+p scattering cross section measurements with ...a positron beam energy of 27.5 GeV and proton beam energies of 920, 575 and 460 GeV. Employing the energy dependence of the cross section, FL is measured in a range of squared four-momentum transfers 12⩽Q2⩽90 GeV2 and low Bjorken x0.00024⩽x⩽0.0036. The FL values agree with higher order QCD calculations based on parton densities obtained using cross section data previously measured at HERA.