Conveners
WG2: Low x and Diffraction: Formal developments and saturation, total cross sections
- Jonathan Hollar (Lawrence Livermore National Laboratory)
- Halina Abramowicz (Tel Aviv University (IL))
- Samuel Wallon
WG2: Low x and Diffraction: Vector meson production, MPI and DPS
- Halina Abramowicz (Tel Aviv University (IL))
- Jonathan Hollar (Lawrence Livermore National Laboratory)
WG2: Low x and Diffraction: Exclusive production
- There are no conveners in this block
WG2: Low x and Diffraction: Diffraction, DVCS, and theory
- There are no conveners in this block
Dr
Krzysztof Kutak
(Instytut Fizyki Jadrowej Polskiej AkademiiNauk)
23/04/2013, 08:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Motivated by p-Pb experiments at Large Hadron Collider which require both knowledge of gluon densities accounting for saturation and for processes at a wide range of $p_t$ we study basic momentum space evolution equations of high energy QCD factorization. Solutions of those equations might be used to form a set of gluon densities to calculate observables in generalized high energy...
Dr
Amir Rezaeian
(Universidad Tรฉcnica Federico Santa Marรญa)
23/04/2013, 08:50
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
The Impact-Parameter dependent Saturation Model is a simple dipole model that incorporates key features of the physics of gluon saturation and matches smoothly to the perturbative QCD dipole expression at large Q^2 for a given x. It was previously shown that the model gives a good description of HERA data suggesting evidence for gluon saturation effects at small x. The model has also been...
Martin Hentschinski
(Brookhaven National Laboratory)
23/04/2013, 09:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We review Lipatov's high energy effective action and show that it is a useful computational tool to calculate QCD scattering amplitudes in the high energy limit. We explain in some detail our recent work where a novel regularization and subtraction procedure has been proposed that allows to extend the use of this effective action beyond tree level. As explicit results we discuss the derivation...
Grigorios Chachamis
(IFIC (CSIC/UV) Valencia)
23/04/2013, 09:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Lipatov's high energy effective action is proving to be a useful computational tool for studying QCD scattering amplitudes in the high energy limit. We explain how we calculate within this framework the full gluon Regge trajectory at two loops using a novel regularization and subtraction procedure.
Michal Deak
(IFIC/CSIC, Universitat de Valencia)
23/04/2013, 09:50
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We solve the modified non-linear extension of the CCFM equation โ KGBJS equation โ numerically for certain initial conditions and compare the resulting gluon Green functions with those obtained from solving the original CCFM equation and the BFKL and BK equations for the same initial conditions. We improve the low transversal momentum behaviour of the KGBJS equation by a small modification.
Dr
Andreas van Hameren
(IFJ PAN)
23/04/2013, 10:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
While several approaches and their implementations for the
efficient calculation of scattering amplitudes within collinear
factorization applied to hadron scattering exist, no automated tool
exist to achieve the same within frameworks of factorization that
allow for the initial-state partons, entering the hard partonic
process, to have non-vanishing transversal momentum components....
Stephane Munier
(Ecole polytechnique)
23/04/2013, 11:00
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Perturbative QCD is the appropriate tool to describe many important properties of the inclusive observables measured at electron-proton (or ion) colliders, such as the energy dependence of the total cross sections in well-chosen kinematical regions. This is because the electron may effectively be replaced by its cloud of photons, whose virtualities provide a hard scale.
At hadron colliders...
Mirko Berretti
(Sezione di Pisa (IT))
23/04/2013, 11:20
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
The TOTEM experiment at the LHC has performed the first luminosity-independent measurements of the total proton-proton cross-section at sqrt(s) = 7 TeV and 8 TeV. These measurements are based on the optical theorem and require simultaneous measurements of the elastic rate by measuring the outgoing protons with Roman Pots and of the inelastic rate, accomplished with the forward charged-particle...
Prof.
Konstantin Goulianos
(The Rockefeller University)
23/04/2013, 11:40
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Predictions of diffractive, elastic, total, and total-inelastic pp cross sections based on the renormalization model for diffraction are compared with recent measurements at the LHC.
Cyrille Marquet
23/04/2013, 14:20
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Within the Color Glass Condensate (CGC) framework, I will discuss particle production in the collision of a dilute projectile with a dense hadronic target. For years CGC studies focused on the dipole scattering amplitude, and it's evolution towards high energies or small x. One has now reached an accuracy sufficient to quantitatively describe single inclusive particle production in p+A type...
Maddalena Frosini
(Universita e INFN (IT))
23/04/2013, 14:40
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Studies of quarkonia production in the forward region provide important tests of NRQCD. The LHCb experiment has collected a dataset corresponding to an integrated luminosity of about 3 fb-l in
proton-proton collisions at sqrt(s)= 7 and 8 TeV. We present studies of the production and polarisation of the J/psi, psi(2S) and chi_c charmonium states as well as those of Upsilon and chi_b...
Panagiotis Katsas
(Deutsches Elektronen-Synchrotron (DE))
23/04/2013, 15:00
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Measurements of the pseudorapidity distribution of charged hadrons in pp collisions at 8 TeV are presented, and compared to the predictions of Monte Carlo models.
Anastasia Grebenyuk
(Deutsches Elektronen-Synchrotron (DE))
23/04/2013, 15:20
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We suggest that, if current measurements of inclusive jet and leading track production for central rapidities at the LHC are extended to lower transverse momenta, one could define a visible cross section sensitive to the unitarity bound set by the recent determination of the inelastic proton-proton cross section.
Kajari Mazumdar
(Tata Inst. of Fundamental Research (IN))
23/04/2013, 15:40
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Studies of the underlying event in p-p collisions at 0.9, 2.76, and 7 TeV are presented, using leading charged tracks at central rapidities, and the energy density measured at forward rapidities. The results are compared to model predictions, and provide constraints on the tuning of Monte Carlo parameters at the LHC.
Mr
Michal Deak
(IFIC/CSIC, Universitat de Valencia)
23/04/2013, 16:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We use the heavy quark impact factor at NLO order and multi-regge kinematic regime to calculate of single bottom production cross section at large rapidity at LHC energies.
Markus Diehl
(DESY)
23/04/2013, 16:50
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
I discuss the possible size and the observable consequences of interparton correlactions in multiple hard scattering processes.
Emilia Lewandowska
(Institute of Nuclear Physics PAN)
23/04/2013, 17:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Double parton distributions (DPDs) are used in the QCD description of double parton scattering. The DPDs evolve with hard scales through relatively new QCD evolution equations and obey nontrivial sum rules: momentum and valence quark number sum rules. Based on a constructed numerical program, we present recent results on the QCD evolution of the DPDs. In particular, we discuss the problem how...
Dr
Paolo Bartalini
(National Taiwan University (TW))
23/04/2013, 17:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
to be defined
Miroslav Myska
(Acad. of Sciences of the Czech Rep. (CZ))
23/04/2013, 17:50
Structure functions and Parton Densities
Talk in Parallel Session at DIS2013
The production of W bosons in association with two jets in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV has been investigated using data collected with the ATLAS detector. The fraction of events arising from double-parton scattering
has been measured through the pT balance between the two jets. The measurement provides new information on the proton structure and is...
Victor Fadin
(Budker Institute of Nuclear Physics Novosibirsk)
23/04/2013, 18:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
In the BFKL approach scattering amplitudes are given by convolutions of impact factors of colliding particles and Green functions of two reggeized gluons. A possibility to rearrange radiative corrections to scattering amplitudes between the impact factors
and the Green functions leads to an ambiguity of NLO BFKL kernels for equations of evolution of the Green functions with energy....
Wolfgang Schaefer
(Institute of Nuclear Physics PAN)
24/04/2013, 08:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Heavy nuclei at collider energies are a source of high-energy Weizsรคcker-Williams photons. This photon flux may be utilized to study high-energy photon-nucleus interactions. We will first discuss the coherent diffractive production of heavy vector mesons on nuclear targets and show how it probes the unintegrated glue of the nucleus in the saturation domain. We present our calculations for...
Dr
Franck Sabatie
(CEA Saclay)
24/04/2013, 08:50
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We systematically evaluate observables for hard exclusive electroproduction of real photons and compare them to experiment using a set of Generalized Parton Distributions (GPDs) whose parameters are constrained by Deeply Virtual Meson Production data, nucleon form factors and parton distributions. The Deeply Virtual Compton Scattering amplitudes are calculated to leading-twist accuracy and...
Nelly Gogitidze
(DESY)
24/04/2013, 09:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Cross sections for elastic and proton dissociative photoproduction of J/ mesons are measured simultaneously in electron proton collisions at HERA using the H1 detector. Two data sets are analysed, one collected at the nominal ep centre-of-mass energy of
sqrt{s}\approx 320 GeV and having an integrated luminosity of 130 pbโ1 and one recorded with a reduced proton beam energy resulting in...
Dr
Ronan Mcnulty
(University College Dublin (IE))
24/04/2013, 09:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Exclusive J/psi and psi(2S) vector meson production has been observed in the dimuon channel using the LHCb detector. The cross-section times branching fractions to two muons with pseudorapidities between 2.0 and 4.5 are measured and are found to be in good agreement with results from previous experiments and theoretical predictions. The J/psi photoproduction cross-section is reported as a...
Prof.
Konstantin Goulianos
(Rockefeller University (US))
24/04/2013, 09:50
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We would like to present results on diffractive and exclusive production from CDF experiment including new study of ppbar collisions at the Tevatron that have 2 or 4 charged hadrons in the central region with |eta|<1.3 with large rapidity gaps on either side. We use data taken at sqrt{s}=1960 and 900 GeV. This data provides a useful window on hadron spectroscopy, as well as providing...
Gustavo Gil Da Silveira
(Universite Catholique de Louvain (BE))
24/04/2013, 10:10
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We present results on exclusive production from CMS, including a first search for exclusive gammagamma->WW, and limits on anomalous quartic gauge couplings. We also present measurements of exclusive gammagamma->mumu and gammagamma->ee production, and the first limits on central exclusive production of photon pairs at 7 TeV.
Eugenio Scapparone
(INFN-Bologna(IT))
24/04/2013, 11:00
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
Ultra-relativistic heavy ions generate strong electromagnetic fields which offer
the possibility to study gamma-gamma and gamma-nucleus interactions at theLHC in the so called ultra-peripheral collisions (UPC). The J/psi photoproduction in UPC events in sensitive to the gluon distribution of the interacting nuclei, providing information on the nuclear gluon shadowing at Bjorken-x ranging...
Antoni Szczurek
(Institute of Nuclear Physics)
24/04/2013, 14:00
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We calculate differential distributions for the $p p \to p p \gamma$ reaction at the LHC energy $\sqrt{s} = 14$~TeV.
We consider diffractive classical bremsstrahlung mechanisms including effects of non point-like nature of protons.
In addition, we take into account (vector meson)-pomeron, photon-pion
as well as photon-pomeron exchange processes
for the first time in the...
Antoni Szczurek
(Institute of Nuclear Physics)
24/04/2013, 14:20
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We discuss the diffractive dissociation of gluons into heavy quark pairs.
The particular mechanism is similar to the diffractive dissociation
of virtual photons into quarks, which drives diffractive deep inelastic
production of charm in the low-mass diffraction, or large $\beta$-region.
The amplitude for the $g p \to Q \bar Q p$ is derived in the impact
parameter and momentum space. The...
Cristiano Brenner Mariotto
(U)
24/04/2013, 14:40
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
In this work we study the prompt photon production in single and double diffractive processes considering the resolved Pomeron model. We estimate the rapidity and transverse momentum dependence of the cross section for the production of two photons and of a photon and a jet. We show that these processes are sensitive to the pomeron structure. In contrast with the dijet and heavy quark...
Dr
Ruben Sandapen
(University of Moncton & Mount Allison University)
24/04/2013, 15:00
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We show that AdS/QCD generates predictions for the rate of diffractive ฯ-meson electroproduction that are in agreement with data collected at the HERA electron- proton collider. We also predict the exclusive two pion spectra recently measured at HERA using AdS/QCD holographic light-front wave functions for the ฯ-meson and its radial excitations.
Jan Olsson
(DESY)
24/04/2013, 15:20
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an...
Dr
Robert Ciesielski
(Rockefeller University (US))
24/04/2013, 15:40
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We present measurements of soft and hard diffraction at the LHC, including measurements of diffractive dijets at 7 TeV. We also show the first candidates for central dijet production with both leading protons tagged at the LHC, using the combined CMS and TOTEM detectors.
Adrien Besse
(LPT Orsay)
24/04/2013, 16:30
Small-x, Diffraction and Vector Mesons
Talk in Parallel Session at DIS2013
We discuss the high-energy exclusive electroproduction of rho
mesons, for both longitudinal and transversal polarizations.
The theoretical description of the cross-section is based on the
perturbative calculations of the transition gamma*L -> rhoL and gamma*T
-> rhoT, i.e. impact factors, within the collinear factorization of QCD.
We show how these impact factors can be related to...
