244 Works
Status of polarized structure functions.
Claude Marchand
An experimental overview on polarized structure functions of the nucleon
is given. It covers results from experiments performed at CERN, HERA,
JLAB and RHIC. Latest results on quark and gluon helicities are discussed,
as well as results on Transverse Momentum Dependent distribution functions
(TMD).
Recent WW, WZ and ZZ Results from the Tevatron.
Mika Vesterinen
Contribution to Proceedings
Forward Drell-Yan plus backward jet as a test of BFKL evolution.
Martin Hentschinski & Clara Salas
We study Drell-Yan plus jet events where the gauge boson is produced
in the forward direction of one of the colliding protons and a jet
is produced in the forward direction of the second proton. The resulting
large rapidity difference between the final states then opens up
the phase space for BFKL evolution. First numerical results on partonic
level are provided.
Inclusive Jet Production Measured with ATLAS and Constraints on PDFs.
Bogdan Malaescu
Inclusive jet and dijet double-differential cross sections have been
measured in proton-proton collisions at a centre-of-mass energy of
7~TeV using the ATLAS detector at the LHC. The cross sections were
measured using jets clustered with the anti-$k_{t}$ algorithm. The
measurements are performed in the jet rapidity range $\vert{\rm y}\vert < 4.4$,
covering jet transverse momenta from 20~GeV to 1.5~TeV and dijet invariant
masses from 70~GeV to 5~TeV. The data are compared to expectations
based on...
A new approach to gluon-quark multiplicity ratio.
Paolo Bolzoni
We present a new approach in considering and including both the perturbative
and the nonperturbative contributions to the multiplicity ratio
$r$ of gluon and quark jets. The new method is motivated by recent
developments in timelike small-x resummation obtained in the $\overline{\rm
MS}$ factorization scheme. A global analysis to fit the available
data is also presented.
Higher Twist contributions to the Structure Functions $F_2(x,Q^2)$ and $g_2(x,Q^2)$.
Johannes Bluemlein & Helmut Boettcher
We report on recent results on higher twist contributions to the unpolarized
structure functions $F_2^{p,d}(x,Q^2)$ at N$^3$LO in the large x
region and constraints on the twist--3 contribution to polarized
structure function $g_2(x,Q^2)$.
Heavy Quark Production in the ACOT Scheme Beyond NLO.
T. Stavreva, F. I. Olness, I. Schienbein, T. Jezo, A. Kusina, K. Kovarik & J. Y. Yu
We analyze the properties of the ACOT scheme for heavy quark production
and make use of the $\msbar$ massless results at NNLO and N$^{3}$LO
for the structure functions $F_{2}$ and $F_{L}$ in neutral current
deep-inelastic scattering to estimate the higher order corrections.
The dominant heavy quark mass effects at higher orders can be
taken into account using the massless Wilson coefficients together
with an appropriate slow-rescaling prescription implementing the
phase space constraints. Combining the exact...
Measurement of charm production in DIS with inclusive secondary vertices and determination of $F_2^{c\bar c}$ with the ZEUS detector at HERA.
Vladyslav Libov
Charm production in deep inelastic scattering has been measured with
the ZEUS detector using the full HERA II data set. The charm content
in events with a jet has been extracted using the decay length significance
and invariant mass of secondary vertices. Differential cross sections
as a function of the photon virtuality $Q^2$, Bjorken x, jet transverse
energy $E_T^{jet}$ and jet pseudorapidity $\eta^{jet}$ were measured
and compared to theoretical predictions. The open charm contribution
to...
Diffractive and exclusive processes at small x at the Large Hadron-electron Collider.
Anna M. Stasto
In this talk, I will discuss the opportunities for the exploration
of physics phenomena at low values of Bjorken x at the Large Hadron-electron
Collider. In particular, the prospects for the measurements of the
diffractive and exclusive processes will be outlined.
Measurement of the Azimuthal Correlation between the most Forward Jet and the Scattered Positron in Deep-Inelastic Scattering at HERA.
Lidia Goerlich
Deep-inelastic positron-proton scattering events at low $Q^2$ with
a forward jet, produced at small angles with respect to the proton
beam, are measured with the H1 detector at HERA. A subsample of
events with an additional jet in the central region is also studied.
For both samples differential cross sections and normalised distributions
are measured as a function of the azimuthal angle difference, $\Delta
\phi$, between the forward jet and the scattered positron in bins...
Parton shower contributions to jets from high rapidities at the LHC.
M. Deak, F. Hautmann, H. Jung & K. Kutak
We discuss current issues associated with the dependence of jet
distributions at the LHC on the behavior of L QCD parton showers
for high rapidities.
Dijet Production in QCD and N=4 SYM.
Grigorios Chachamis, Jose Daniel Madrigal & Agustin Sabio Vera
We investigate dijet production at large rapidity separation in QCD
and ${\cal N}=4$ SYM, showing that both theories give similar predictions
for observables only sensitive to conformal properties of the scattering
such as ratios of azimuthal angle correlations. Renormalization prescriptions
are important in this comparison.
Spin structure of the forward nucleon charge-exchange reaction n + p --> p + n and the deuteron charge-exchange breakup.
Valery V. Lyuboshitz & Vladimir L. Lyuboshitz
The structure of the nucleon charge-exchange process \,$n + p \rightarrow
p + n$ \,is investigated basing on the isotopic invariance of the
nucleon-nucleon scattering. Using the operator of permutation of the
spin projections of the neutron and proton, the connection between
the spin matrices, describing the amplitude of the nucleon charge-exchange
process at zero angle and the amplitude of the neutron elastic scattering
on the proton in the ``backward" direction, has been obtained. Due...
Overview of Deeply Virtual Compton Scattering at HERMES.
Morgan Murray
Deeply Virtual Compton Scattering represents the best experimental
channel through which to understand Generalised Parton Distributions.
The HERMES experiment measured the most diverse set of DVCS results
of any experiment; this talk discusses the most recent sets of DVCS
results released by HERMES and the unique experimental conditions
found at HERMES that facilitated the measurements. We also examine
the various ways in which the HERMES experimental measurements are
being used to constrain GPDs and how...
Deeply Virtual Compton Scattering with CLAS and CLAS12.
Daria Sokhan
Two very effective means of accessing Generalised Parton Distributions
of the nucleon are Deeply Virtual Compton Scattering (DVCS) and Meson
Production (DVMP). Jefferson Laboratory, USA, previously operational
with a 6 GeV electron beam and currently undergoing an upgrade to
12 GeV, is ideally suited for measuring these processes. This paper
focuses on a selection of recent results from the very active DVCS
experimental programme with the large angle spectrometer CLAS, and
introduces the exciting programme...
Hard Exclusive $\rho^0$-Meson Production at COMPASS.
Heiner Wollny
New results for the transverse target spin azimuthal asymmetry $A_{UT}^{\sin(\phi-\phi_S)}$
for hard exclusive $\rho^0$-meson production on a transversely polarised
$^6$LiD and NH$_3$ target will be presented. The measurement was
performed with the COMPASS detector using the $160$\,GeV/$c$ muon
beam of the SPS at CERN. The asymmetry is sensitive to the nucleon
helicity-flip generalised parton distribution $E$, which is related
to the orbital angular momentum of quarks in the nucleon.
Top Quark Pair Production beyond the Next-to-Leading Order.
Valentin Ahrens, Andrea Ferroglia, Matthias Neubert, Ben D. Pecjak & Li Lin Yang
We report on recent calculations of the total cross section and
differential distributions of top quark pair production at hardon
colliders, including the invariant mass distribution, the transverse
momentum and rapidity distributions, as well as the forward-backward
asymmetry. The calculations are based on soft gluon resummation
at the next-to-next-to-leading logarithmic accuracy.
Progress in the dynamical parton distributions.
Pedro Jimenez-Delgado
The present status of the (JR) dynamical parton distribution functions
is reported. Different theoretical improvements, including the determination
of the strange sea input distribution, the treatment of correlated
errors and the inclusion of alternative data sets, are discussed.
Highlights in the ongoing developments as well as (very) preliminary
results in the determination of the strong coupling constant are presented.
The statistical model for parton distributions.
Claude Bourrely, Franco Buccella & Jacques Soffer
The phenomenological motivations, the expressions and the comparison
with experiment of the parton distributions inspired by the quantum
statistics are described. The Fermi-Dirac expressions for the quarks
and their antiparticles automatically account for the correlation
between the shape and the first moments of the valence partons, as
well as the flavor and spin asymmetries of the sea. One is able to
describe with a small number of parameters both unpolarized and polarized
structure functions.
Measurement of Dijet Production in Diffractive Deep-Inelastic Scattering with a Leading Proton at HERA.
Richard Polifka
The latest results from the H1 experiment on the diffractive dijet
production in deep-inelastic scattering are presented. The first jet
measurements with a tagged leading proton are described. The results
are discussed in terms of diffractive parton densities and Regge factorisation.
Central Exclusive Production in $p\bar{p}$ Collisions at CDF II.
Erik Bruecken
We report central exclusive production results studied at the Run
II Collider Detector at Fermilab with focus on our recently published
paper on the first observation of exclusive $\gamma\gamma$ production
in $p\bar{p}$ collisions at $\sqrt{s} = $\unit{1.96}{\TeV} at the
Tevatron. In particular, starting from earlier studies by the CDF
collaboration, we discuss exclusive dijet, dilepton, $Z$, $J/\Psi$
and $\chi_c$ productions and finally our recent observation of exclusive
diphoton production. Whereas the lepton pairs are purely...
Exclusive Dimuon production at LHCb.
Dermot Moran
We report on preliminary results for the measurement of exclusive
dimuon production at LHCb. Cross-section measurements for exclusive
$J/\psi$, $\psi\prime$ and for non-resonant production $p+p\rightarrow
p+ \mu^+ \mu^- +p$ are presented and comparisons made with theory.
The additional requirement of a single photon allows the the cross-section
for exclusive $\chi_c$ production to be measured and also the relative
contribution of $\chi_c^0$,$\chi_c^1$,$\chi_c^2$ to be determined.
Exclusive Production of the MSSM Higgs Bosons at the LHC.
S. Heinemeyer, V. A. Khoze, Marek Tasevsky & Georg Weiglein
We review the prospects for Central Exclusive Production (CEP) of
BSM Higgs bosons at the LHC using forward proton detectors proposed
to be installed at standard benchmark scenarios and in scenarios
compatible with the Cold Dark Matter relic abundance and other precision
measurements. Following results of the LHC Higgs boson searches,
we investigate a hypothesis that candidates found at a mass of \unit{125}{\GeV}
are compatible with light CP-even MSSM Higgs bosons. We show that
CEP...
High Energy Exclusive Leptoproduction of the $\rho$-meson: Theory and Phenomenology.
I. V. Anikin, Adrien Besse, D. Yu. Ivanov, B. Pire, L. Szymanowski & S. Wallon
AWe describe the hard leptoproduction of transversally polarized rho-meson,
up to twist~3 accuracy, including 2- and 3- particles Fock-states,
in the HERA kinematics of high center-of-mass energy. We first build
a model based on a simple approach to the unintegrated gluon density
(the parton impact factor) that we compare with H1 and ZEUS data for
the ratios of helicity amplitudes $T(\gamma^{*}_T \to \rho_T)/T(\gamma^{*}_L
\to \rho_L)$ and $T(\gamma^{*}_T \to \rho_L)/T(\gamma^{*}_L \to \rho_L)$
and get a good...
$W$, $Z$ and jet central exclusive production at the LHC.
O. Kepka, A. Dechambre, M. Trzebinski, R. Staszewski, E. Chapon & C. Royon
We study the $W$/$Z$ pair production via two-photon exchange at the
LHC and give the sensitivities on trilinear and quartic gauge anomalous
couplings between photons and $W$/$Z$ bosons. Tagging the protons
in the final state in the ATLAS Forward Physics detectors as an example
allows to improve the reach on anomalous couplings by four orders
of magnitude reaching the values predicted by extra-dimension theories.
The measurement of the exclusive jet production using the same detectors...