We present a new QCD description of the ATLAS jet veto measurement, using the Banfi-Marchesini-Smye equation to constrain the interjet QCD radiation. This equation resums emissions of soft gluons at ...large angles, at leading-logarithmic accuracy, and accounts for both the so-called Sudakov and nonglobal logarithms. We show that this approach is able to reproduce, with no fitting parameters, the fraction of high-pT forward-backward dijet events which do not contain additional hard emissions in the interjet rapidity range. We also compute the gap fraction in fixed-order perturbation theory to (ProQuest: Formulae and/or non-USASCII text omitted) and show that the perturbative series is unstable at large rapidity intervals.
We describe the discovery of the colorless
C
C
-odd
gluonic compound, the odderon, by the D0 and TOTEM Collaborations by
comparing elastic differential cross sections measured in
pp
p
p
and
p \bar{p}
...p
p
‾
interactions at high energies.
We investigate small-x QCD effects in forward-jet production in deep inelastic scattering in the kinematic regime where the virtuality of the photon and the transverse momentum of the jet are two ...hard scales of about the same magnitude. We show that the data from HERA published by the H1 and ZEUS Collaborations are well described by leading-logarithmic BFKL predictions. Parametrizations containing saturation effects expected to be relevant at higher energies also compare well to the present data. We extend our analysis to Mueller–Navelet jets at the LHC and discuss to what extent this observable could test these small-x effects and help distinguishing between the different descriptions.
We describe the discovery of the colorless
C
C
-odd
gluonic compound, the odderon, by the D0 and TOTEM Collaborations by
comparing elastic differential cross sections in
pp
p
p
and
p \bar{p}
p
p
‾
...interactions at high energies.
We describe the gain on sensitivities to quartic
\gamma \gamma \gamma \gamma
γ
γ
γ
γ
,
\gamma \gamma WW
γ
γ
W
W
and
\gamma \gamma \gamma Z
γ
γ
γ
Z
anomalous couplings and to the search for Axion-Like ...Particles by two or
three orders of magnitude with respect to standard methods at the LHC by
tagging intact protons in the final state.
We show that next-leading logarithmic (NLL) Balitsky–Fadin–Kuraev–Lipatov (BFKL) effects can be tested by the forward-jet cross sections recently measured at HERA. For dσ/dx, the NLL corrections are ...small which confirms the stability of the BFKL description. The triple differential cross section dσ/dxdkT2dQ2 is sensitive to NLL effects and opens the way for an experimental test of the full BFKL theoretical framework at NLL accuracy.
The proton–proton elastic differential cross section
d
σ
/
d
t
has been measured by the TOTEM experiment at
s
=
2.76
TeV
energy with
β
∗
=
11
m
beam optics. The Roman Pots were inserted to 13 times ...the transverse beam size from the beam, which allowed to measure the differential cross-section of elastic scattering in a range of the squared four-momentum transfer (|
t
|) from 0.36 to
0.74
GeV
2
. The differential cross-section can be described with an exponential in the |
t
|-range between 0.36 and
0.54
GeV
2
, followed by a diffractive minimum (dip) at
|
t
dip
|
=
(
0.61
±
0.03
)
GeV
2
and a subsequent maximum (bump). The ratio of the
d
σ
/
d
t
at the bump and at the dip is
1.7
±
0.2
. When compared to the proton–antiproton measurement of the D0 experiment at
s
=
1.96
TeV
, a significant difference can be observed. Under the condition that the effects due to the energy difference between TOTEM and D0 can be neglected, the result provides evidence for the exchange of a colourless C-odd three-gluon compound state in the
t
-channel of the proton–proton and proton–antiproton elastic scattering.
In the prospect of diffractive Higgs production at the LHC collider, we give an extensive study of Higgs boson, dijet, diphoton and dilepton production at hadronic colliders via diffraction at both ...hadron vertices. Our model, based on non-factorizable pomeron exchange, describes well the observed dijet rate observed at Tevatron run I. Taking the absolute normalization from data, our predictions are given for diffractive processes at Tevatron and LHC. Stringent tests of our model and of its parameters using data being taken now at Tevatron run II are suggested. These measurements will also allow to discriminate between various models and finally to give precise predictions on diffractive Higgs boson production cross-section at the LHC.
Abstract The TOTEM collaboration has measured the elastic proton-proton differential cross section $$\mathrm{d}\sigma /\mathrm{d}t$$ d σ / d t at $$\sqrt{s}=13$$ s = 13 TeV LHC energy using ...dedicated $$\beta ^{*}=90$$ β ∗ = 90 m beam optics. The Roman Pot detectors were inserted to 10 $$\sigma $$ σ distance from the LHC beam, which allowed the measurement of the range 0.04 GeV $$^{2}$$ 2 ; 4 GeV $$^{2}$$ 2 $$$$ in four-momentum transfer squared | t |. The efficient data acquisition allowed to collect about 10 $$^{9}$$ 9 elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-| t | tail. The average nuclear slope has been found to be $$B=(20.40 \pm 0.002^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ B = ( 20.40 ± 0 . 002 stat ± 0 . 01 syst ) GeV $$^{-2}$$ - 2 in the | t |-range 0.04–0.2 GeV $$^{2}$$ 2 . The dip position is $$|t_{\mathrm{dip}}|=(0.47 \pm 0.004^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ | t dip | = ( 0.47 ± 0 . 004 stat ± 0 . 01 syst ) GeV $$^{2}$$ 2 . The differential cross section ratio at the bump vs. at the dip $$R=1.77\pm 0.01^{\mathrm{stat}}$$ R = 1.77 ± 0 . 01 stat has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.
We show that the forward-jet measurements performed at HERA allow for a detailed study of corrections due to next-to-leading logarithms (NLL) in the Balitsky–Fadin–Kuraev–Lipatov (BFKL) approach. ...While the description of the dσ/dx data shows small sensitivity to NLL-BFKL corrections, these can be tested by the triple differential cross section d
3
σ/dxdk
T
2
dQ
2
recently measured. These data can be successfully described using a renormalization-group improved NLL kernel, while the standard next-to-leading-order QCD or leading-logarithm BFKL approaches fail to describe the same data in the whole kinematic range. We present a detailed analysis of the NLL scheme and renormalization-scale dependences and also discuss the photon impact factors.
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