A
bstract
The cross section of the diffractive process
e
+
p
→
e
+
Xp
is measured at a centre-of-mass energy of 318 GeV, where the system
X
contains at least two jets and the leading final state ...proton
p
is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities
Q
2
<
2 GeV
2
and in deep-inelastic scattering with 4 GeV
2
< Q
2
<
80 GeV
2
. The results are compared to next- to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep-inelastic scattering.
Model for pp → 4π via 2ρ was outlined. The prediction for the cross section for this process was given for ATLAS and ALICE experimental cuts. This process has suffcient cross section to be observed ...in these experiments.
A
bstract
A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic
ep
scattering at HERA using data collected by the H1 experiment ...corresponding to an integrated luminosity of 290 pb
−1
. The investigated phase space is spanned by the photon virtuality in the range of 4
< Q
2
<
100 GeV
2
and by the fractional proton longitudinal momentum loss
x
ℙ
<
0
.
03. The resulting cross sections are compared with next-to-leading order QCD predictions based on diffractive parton distribution functions and the value of the strong coupling constant is extracted.
Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic
e
p
scattering at HERA are ...presented as a function of the Feynman variable
x
F
and of the centre-of-mass energy of the virtual photon-proton system
W
. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of
131
pb
-
1
. The measurement is restricted to photons and neutrons in the pseudorapidity range
η
>
7.9
and covers the range of negative four momentum transfer squared at the positron vertex
6
<
Q
2
<
100
GeV
2
, of inelasticity
0.05
<
y
<
0.6
and of
70
<
W
<
245
GeV. To test the Feynman scaling hypothesis the
W
dependence of the
x
F
dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.
A third workshop on small-x physics, within the Small-x Collaboration, was held in Hamburg in May 2004 with the aim of overviewing recent theoretical progress in this area and summarizing the ...experimental status.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS ...collaborations at HERA for neutral and charged current ... scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb... and span six orders of magnitude in negative four-momentum-transfer squared, ..., and Bjorken x. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in ... An extraction of ... and results on electroweak unification and scaling violations are also presented.
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