Markus Diehl
(DESY)
03/12/2013, 09:00
MPI & Double Parton Scattering
Talk
I give a brief introduction to the theory of double hard scattering and then discuss recent theory developments and open questions.
Dr
Sunil Bansal
(University of Antwerp (BE))
03/12/2013, 09:40
MPI & Double Parton Scattering
Talk
Double parton scattering (DPS) is studied in proton-proton collisions at a centre-of-mass energy of 7 TeV, using events with a W boson decaying into a muon and neutrino and the presence of two associated jets in the final state. The data sample corresponds to an integrated luminosity of 5 /fb, collected by the CMS detector at the Large Hadron Collider. Observables sensitive to double parton...
Constantinos Melachrinos
(University of Chicago (US))
03/12/2013, 10:20
MPI & Double Parton Scattering
Talk
We present the discovery of associated W+prompt J/psi production and subsequent measurement of the production rate, which is a key observable to furthering understanding of quarkonium production mechanisms. We estimate the relative contributions to the signal from single and double parton scattering and discuss possible implications of this novel final state for study of multiple parton...
Antoni Szczurek
(Institute of Nuclear Physics)
03/12/2013, 11:20
MPI & Double Parton Scattering
Talk
We discuss production of two pairs of $c \bar c$ in proton-proton collisions at the LHC. Both double-parton scattering (DPS) and single-parton scattering (SPS) contributions are included in the analysis. Each step of DPS is calculated within $k_t$-factorization approach, i.e. effectively including next-to-leading order corrections. The conditions how to identify the DPS contribution are...
Fiorella Fionda
(Universita e INFN (IT))
03/12/2013, 11:45
MPI & Double Parton Scattering
Talk
The study of heavy-flavour hadron production as a function of the charged particle multiplicity in pp collisions helps one to understand the interplay between hard and soft QCD processes, in particular it allows one to study the role of Multi-Parton Interactions (MPI). At the LHC energies the MPI might affect not only processes involving light quarks and gluons, but also the hard momentum...
Andrzej Konrad Siodmok
(University of Manchester (GB))
03/12/2013, 12:15
MPI & Double Parton Scattering
Talk
We discuss various issues related to the definition of single and double open charm cross sections. We conclude that LHCb's extraction of sigma_effective, the effective cross section for double-parton scattering, is too large by a factor of two. This correction brings the data from open-charm pairs closer to that from J/psi plus open charm and jet production.
Tristan Arnoldus Du Pree
(Universite Catholique de Louvain (BE))
03/12/2013, 12:40
MPI & Double Parton Scattering
Talk
The production of vector bosons in association with jets from heavy flavor quarks is possibly sensitive to contributions from MPI. This presentation summarizes the status of studies of the production of W+bb and Z+bb at the LHC.
Dr
Alexander Snigirev
(SINP MSU), Prof.
David d'Enterria
(CERN)
03/12/2013, 14:15
MPI & Double Parton Scattering
Talk
The DPS cross sections in p-A and A-A collisions are compared to those in p-p collisions. Such DPS formalism is applied to two different final-states at CERN LHC energies: (i) same-sign W-boson pair production in p-Pb, and (ii) double-J/psi production in Pb-Pb.
Daniele Treleani
(University of Trieste)
03/12/2013, 14:40
MPI & Double Parton Scattering
Talk
The joint study of Double Parton Scatterings, in high energy proton-proton and proton-nucleus collisions, can provide a lot of information on multi-parton correlations. The multi-parton structure is in fact probed in a different way by DPS, in p-p and in p-A collisions. In p-A collisions the interpretation of the experimental results may be however complicated by the presence of interference...
Daniel Ostermeier
(University of Regensburg)
03/12/2013, 15:05
MPI & Double Parton Scattering
Talk
Multi-Parton Interactions become ever more important with increasing hadron collider energies and are highly relevant for the LHC. Therefore, they have to be understood based on first principles within QCD. Unfortunately this is much easier said than done as it calls for a substantial extension of present day collinear perturbative QCD techniques. The most crucial and perhaps most difficult...
Wouter Waalewijn
(UCSD)
05/12/2013, 14:15
MPI & Double Parton Scattering
Talk
I will discuss the framework for double parton scattering that I helped develop, which is based on QCD factorization. The initial state is described by double parton distribution functions, and offers a window into diparton correlations in the proton. I will discuss its renormalization group evolution, which implies that color correlations and parton-exchange interference contributions are...
Prof.
Sergio Scopetta
(Perugia University and INFN)
05/12/2013, 14:40
MPI & Double Parton Scattering
Talk
In a recent paper, double parton correlations have been studied in the valence quark region, by means of constituent quark models.In this framework, two particle correlations are present without any additional prescription, at variance with what happens, for example, in independent particle models, such as the MIT bag model in its simplest version. The conclusions are similar to the ones...
Tomas Kasemets
(DESY)
05/12/2013, 15:05
MPI & Double Parton Scattering
Talk
We examine the effect of double DGLAP evolution on the double parton distributions. Through a series of numerical investigations with focus on two types of parton correlations, we quantify the degree to which evolution affects the dependence on the transverse distance between partons as well as the importance of the different polarized distributions.
Paolo Gunnellini
(Deutsches Elektronen-Synchrotron (DE))
05/12/2013, 15:30
MPI & Double Parton Scattering
Talk
We present measurements of exclusive 4-jet production cross sections as a function of the transverse momentum, pseudorapidity, as well as of correlations in azimuthal angle and transverse momentum balance among the jets. The data sample was collected in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 36...
Dr
Boris Blok
(Technion)
05/12/2013, 16:40
MPI & Double Parton Scattering
Talk
Tevatron studies of multi-jet production in the back-to-back kinematics corresponding to parton momenta x of order 0.01 have confirmed the presence of double hard interactions in a single hadron hadron collision. The independent parton approximation underestimates the observed cross section by a factor of two. In this paper we point at previously overlooked three-parton Interactions that...
Jonathan Gaunt
(DESY)
05/12/2013, 17:05
MPI & Double Parton Scattering
Talk
I will discuss the role of a particular class of graph in the double parton scattering total cross section. These are the '2v1' or `single perturbative splitting' graphs, in which two 'nonperturbatively generated' (NP) ladders interact with two ladders that have been generated via a perturbative 1->2 branching process. I will argue that these graphs do contribute to the LO DPS cross section,...
Valery Khoze
(University of Durham (GB))
05/12/2013, 17:30
MPI & Diffraction
Talk
Diego Ciangottini
(Universita e INFN (IT))
05/12/2013, 17:55
MPI & Double Parton Scattering
