Oleg Kuprash
(DESY)
27/03/2012, 09:00
Hadronic final states
Isolated-photon+jet production in ep collisions at a centre-of-mass energy of 318 GeV has been measured with the ZEUS detector at HERA using an integrated luminosity of up to 300 pb-1. Measurements of prompt-photon+jet cross sections are presented as functions of the photon transverse energy and pseudorapidity in a wide range of exchanged-photon virtuality. In addition, differential gamma+jet...
27/03/2012, 09:20
Hadronic final states
Prompt isolated photon pairs production cross sections, as well as
direct photon production in association with a heavy (b or c) quark jets are presented.
Differential cross sections are presented as a function of several variables.
The results are compared with a next-to-leading order perturbative QCD calculations.
Nikolai Skachkov
(Joint Inst. for Nuclear Research (RU))
27/03/2012, 09:40
Hadronic final states
Photon+jets measurements in ppbar Collisions at D0
Leonardo Carminati
(Università degli Studi e INFN Milano (IT))
27/03/2012, 10:00
Hadronic final states
Isolated prompt photons provide a direct probe of short-distance physics, complementary to
that provided by measurements of jets or vector-bosons. The inclusive prompt photon cross
section has been measured over a wide range of transverse momenta; the diphoton cross section
has also been measured as a function of diphoton mass, total transverse momentum and azimuthal
separation; the cross...
Andrea Banfi
(Freiburg U)
27/03/2012, 11:00
Hadronic final states
We present accurate (NLL+NNLO) predictions for jet-veto efficiencies for Higgs and Z production at the LHC, obtained with the automated resummation program CAESAR. We discuss all sources of theoretical uncertainties associated to the presented results, highlighting which further calculations would be needed in order to reduce them.
Peter Schichtel
(ITP)
27/03/2012, 11:20
Hadronic final states
The properties of jets are used in many LHC physics searches. Higgs
searches use jet vetoes and fixed recoil jet multiplicities. Searches
for new physics particles require a careful distinction of decay jets
from QCD jet radiation. We show that the exclusive number of jets
at hadron colliders can be described with two simple patterns: staircase scaling and Poisson scaling. In photon plus...
Adam Yurkewicz
(Northern Illinois University (US))
27/03/2012, 11:40
Hadronic final states
Differential jet cross sections and distributions have been measure inclusively, in dijet events
and in multijet events, using information from the ATLAS calorimeters and tracking detectors. The inclusive
jet measurements extend from 20 GeV to 1.5 TeV, and the dijet measurements cover a very wide mass range.
Measurements based on tracking alone are sensitive only to the charged-particle...
Thomas Schoerner-Sadenius
(Deutsches Elektronen-Synchrotron (DE))
27/03/2012, 12:00
Hadronic final states
Jets and multi-jets at large rapidities in p-p collisions at the LHC
Jennifer Smillie
27/03/2012, 12:20
Hadronic final states
The theoretical description of multi-jet final states is an issue of
great importance at the LHC. The High Energy Jets (HEJ) framework
offers a new approach to this and provides an all-order resummation of
the dominant contributions from wide-angle QCD radiation. I will give a
brief introduction to the framework and then show comparisons to early
data from ATLAS and CMS analyses and...
Nikolai Skachkov
(Joint Inst. for Nuclear Research (RU))
27/03/2012, 14:00
Hadronic final states
W/Z+jets measurements at D0
Lorenzo Ortolan
27/03/2012, 14:20
Hadronic final states
Inclusive Z boson plus jets cross sections, as well as bottom jet production in association with a Z-boson cross sections,
are measured in a final state where the Z boson has decayed in two muons or electrons.
Results are based on $\sim 9$ fb$ ^{-1}$ of data in $\rm p\bar{p}$ collisions at $\rm \sqrt{s}$ = 1.96 TeV collected with the CDF detector in Run II.
Differential cross sections...
Camille Belanger-Champagne
(McGill University (CA))
27/03/2012, 14:40
Hadronic final states
The production of jets in association with a W or Z boson in proton-proton collisions at 7 TeV
is an important process to understand in QCD. The cross section, differential in several kinematics variables,
has been measured up to high jet multiplicities and compared to new higher-order QCD calculations. The ratio
of (Z + a single jet)/(W + a single jet) can provide a very precise test of...
Frank Siegert
(Albert-Ludwigs-Universitaet Freiburg (DE))
27/03/2012, 15:00
Hadronic final states
The MC@NLO method as implemented in the Sherpa MC generator is
presented using the production of W-bosons in conjunction with up to
three jets as an example. Corresponding results computed at next-to
leading order in QCD and including parton shower corrections are
compared to recent experimental data from the Large Hadron Collider.
Stefan Prestel
(L)
27/03/2012, 15:20
Hadronic final states
We present the recent implementation of CKKW-L merging inside Pythia8, and comment on the treatment of multiparton interactions in the context of matrix element merging. Since multiple interactions inside Pythia8 are
fully interleaved with space- and time-like showers, care has to be taken
when allowing for MPI. Further, we will discuss the uncertainties of the
implementation.
Simon Plaetzer
(DESY Hamburg)
27/03/2012, 15:40
Hadronic final states
Parton shower Monte Carlos are by now standard tools to simulate
hadronic final states. Having seen a tremendous improvement of
combining parton showers and fixed order calculations in recent years,
efforts are now underway to improve the shower approximations
themselves, as well.
In this contribution we will present first steps towards including
subleading colour contributions into...
Dr
Michal Deak
(Universidade de Santiago de Compostela)
27/03/2012, 16:30
Hadronic final states
We present a subtraction method for including next to leading order corrections to a 2 to 2 jet production process in kt-factorisation equivalent to a jet matching procedure in Monte Carlo generators. We study the improvement in soft cut dependance.
Mr
Maxim Malyshev
(SINP MSU)
27/03/2012, 16:50
Hadronic final states
In the framework of the kt-factorization approach, the production of unpolarized Drell-Yan lepton pair at high energies is studied. The consideration is based on the O(alpha) and $O(alpha alpha_s) off-shell partonic matrix elements with virtual photon and Z boson exchange. The calculations include leptonic decays of Z bosons with full spin correlations as well as gamma - Z interference. The...
Daniel Wilhelm
(Mainz U)
27/03/2012, 17:10
Hadronic final states
We discuss the differential cross sections for electroweak gauge-boson and Higgs production at small and very small transverse momentum q_T.
Large logarithms are resummed using soft-collinear effective theory.
The collinear anomaly generates a non-perturbative scale q^∗, which protects the processes from receiving large long-distance hadronic contributions. A numerical comparison of our...
Jason Gallicchio
(UC Davis)
27/03/2012, 17:30
Hadronic final states
Distinguishing light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover,...
Daniel Andreas Britzger
(Ludwig-Maximilians-Universitat Munchen)
27/03/2012, 17:50
Hadronic final states
New results on normalised inclusive jet, di-jet and trijet differential cross sections in neutral current deep-inelastic ep scattering (DIS) based on a regularised unfolding procedure are presented. Detector effects like acceptance and migrations as well as statistical correlations between the multi-jets and the inclusive DIS events are taken into account in this procedure. The DIS phase space...
ewald paul
(P)
27/03/2012, 18:10
Hadronic final states
Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q2 < 1 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb-1.
Jets were identified in the laboratory using the kt cluster algorithm in the longitudinally inclusive mode. Cross sections are presented as functions of the jet pseudorapidity, etajet,and the jet...
Ferenc Sikler
(Hungarian Academy of Sciences (HU))
28/03/2012, 13:30
Hadronic final states
Inclusive hadron production (multiplicities and spectra) in p-p
collisions in CMS
Markward Britsch
(Max-Planck-Gesellschaft (DE))
28/03/2012, 13:50
Hadronic final states
Due to its unique pseudorapidity coverage and the possibility of providing measurements at low transverse momenta, the LHCb detector allows unique insight into particle production in the forward region at the LHC. The latest LHCb soft-QCD results, the measurements of charged particle multiplicity at 7 TeV and the measurement of the p/p, K-/K+, π-/π+, (p+p)/(π-+π+), (K-+K+)/( π-+π+ )...
Ms
Nour Makke
(Trieste UNiversity, INFN)
28/03/2012, 14:10
Hadronic final states
Fragmentation functions, which turn partons into non-perturbative hadronic bound states in hard-scattering reactions, play a very important role in our understanding of the proton structure. Currently, our knowledge of fragmentation functions originates mainly from existing global QCD analyses which are mostly based on inclusive measurements in electron-positron annihilation process. While...
Mr
Gevorg Karyan
(A.I. Alikhanyan National Science Laboratory)
28/03/2012, 14:30
Hadronic final states
Hadron multiplicity ratios in semi-inclusive deep-inelastic scattering have been measured on neon, krypton and xenon targets relative to deuterium using the 27.6 GeV beam of HERA at the HERMES experiment. They are presented for pions (π+, π-), kaons (K+, K-), protons and anti-protons as a function of the virtual photon energy ν, its virtuality Q2, the fractional hadron energy z and the...
Iris Abt
(Werner-Heisenberg-Institut)
28/03/2012, 14:50
Hadronic final states
Scaled momentum distributions for the strange hadrons K0s and
Lambda/Lambdabar were measured in deep inelastic ep scattering
with the ZEUS detector at HERA using an integrated luminosity of 330 pb-1. The evolution of these distributions with the photon virtuality,
Q2, was studied in the kinematic region 10 < Q2 < 40000 GeV2 and
0.001 < x < 0.75, where x is the Bjorken scaling variable....
Dr
Valery Lyuboshitz
(Joint Institute for Nuclear Research, Dubna, Russia)
28/03/2012, 15:10
Hadronic final states
The phenomenological structure of inclusive cross sections of the
production of two neutral K mesons in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions is investigated taking into account the strangeness conservation in strong and electromagnetic
interactions. Relations describing the dependence of the correlations of two short-lived and two long-lived neutral kaons
$K^0_S...
Adam Robert Davison
(University College London (UK))
28/03/2012, 16:00
Hadronic final states
The internal structure of jets produced in proton-proton collisions at 7 TeV centre-of-mass energy
provides a direct test of QCD calculations of gluon and quark radiation, as well as having sensitivity
to hadronisation and underlying event. The transverse energy distribution around the jet core has been measured,
as well as the fragmentation of a jet into charged particles. Jet shapes -...
Simone Marzani
(IPPP Durham)
28/03/2012, 16:20
Hadronic final states
We study the jet-mass distribution for jets produced in hadron-hadron collision in QCD. In order to obtain reliable phenomenological results we resum to all-order in perturbation theory those contributions coming from collinear and soft gluons. Beyond the leading-logarithmic accuracy the resummation is made more complicated by the presence of non-global logarithms and logarithms related to the...
Zhao Li
(Michigan State University)
28/03/2012, 16:40
Hadronic final states
Jet Substructure at Hadron Colliders
道久 竹内
(Heidelberg)
28/03/2012, 17:00
Hadronic final states
Top momentum reconstruction often plays an important role for new physics signal reconstruction at the LHC. In principle for a hadronically decaying top, it is possible to reconstruct its momentum fully but one suffers from large QCD and combinatorial backgrounds.
Starting from geometrically large sizes of jets and looking into their substructure, we can efficiently reduce these background....
Hans Jozef H Van Haevermaet
(University of Antwerp (BE))
29/03/2012, 11:00
Hadronic final states
Characterization of the underlying event in p-p collisions in CMS
Dr
Arthur Moraes
(University of Glasgow (GB))
29/03/2012, 11:20
Hadronic final states
The majority of proton-proton collisions at the LHC contain only soft, low transverse-momentum scatters. Such
scatters also occur between the remnants of the protons in conjunction with short-distance, high momentum
scatters. Measurements of soft particle production and energy flow are presented fir a wide range of different
kinematic selections; correlations between the produced...
Dmytro Volyanskyy
(Max-Planck-Gesellschaft (DE))
29/03/2012, 11:40
Hadronic final states
We present the results on the energy flow measured with minimum-bias data collected by the LHCb experiment in $pp$ collisions at $\sqrt{s}=7$~TeV for inclusive minimum bias interactions, hard scattering processes and events with enhanced or suppressed fractions of diffractive contributions. The measurements are performed in the pseudorapidity range $2<\eta<5$ which corresponds to the main...
Anna Zsigmond
(Hungarian Academy of Sciences (HU))
29/03/2012, 12:00
Hadronic final states
Inelastic cross section measurement in p-p collisions in CMS
Christian Roehr
(K)
29/03/2012, 12:20
Hadronic final states
We review the modelling of multiple interactions in the event generator
Herwig++ and study implications of recent tuning efforts to Tevatron and
LHC data. A crucial ingredient to a successful description of minimum
bias and underlying event observables is a model for colour
reconnection. Improvements to this model inspired by statistical physics
are presented.
