### Conveners

#### WG2 QCD and Hadronic Final States

- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)
- Frank Tackmann (DESY)

#### WG2 QCD and Hadronic Final States

- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)
- Frank Tackmann (DESY)

#### WG2 QCD and Hadronic Final States

- Frank Tackmann (DESY)
- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)

#### WG2 QCD and Hadronic Final States

- Frank Tackmann (DESY)
- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)

#### WG2 QCD and Hadronic Final States

- Simon Plätzer (DESY Theory Group)
- Frank Tackmann (DESY)
- Shima Shimizu (Kobe University)

#### WG2 QCD and Hadronic Final States

- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)
- Frank Tackmann (DESY)

#### WG2 QCD and Hadronic Final States

- Shima Shimizu (Kobe University)
- Simon Plätzer (DESY Theory Group)
- Frank Tackmann (DESY)

#### WG2 QCD and Hadronic Final States

- Frank Tackmann (DESY)
- Simon Plätzer (DESY Theory Group)
- Shima Shimizu (Kobe University)

Dr
Gevorg Karyan
(Yerevan Physics Institute)

4/12/16, 9:15 AM

QCD and Hadronic Final States

Bose–Einstein correlations of like-sign charged hadrons produced in deep-inelastic electron and positron scattering are studied in the HERMES experiment using nuclear targets of 1H, 2H, 3He, 4He, N, Ne, Kr, and Xe. A Gaussian approach is used to parametrize a two-particle correlation function determined from events with at least two charged hadrons of the same sign charge. This correlation...

Klaudia Burka
(Polish Academy of Sciences)

4/12/16, 9:40 AM

QCD and Hadronic Final States

ATLAS measurement of azimuthal correlations between particle pairs at large pseudorapidity separation in pp and pPb collisions are presented. The data were collected using a combination of the minimum-bias and high track-multiplicity triggers. A detailed study of the dependence of two-particle correlations on the charged particle multiplicity, transverse momentum of the pair constituents and...

Karoly Urmossy
(Shandong University, Jinan China; Wigner RCP Hungary)

4/12/16, 10:05 AM

QCD and Hadronic Final States

It has been shown that power-law hadron spectra observed in jets stemming from high-energy ee and pp collisions can be described by a statistical hadronisation model based on microcanonical statistics and superimposed Negative-Binomial (NBD) multiplicity fluctuations [1,2,3]. In this talk, applications of this model to ep DIS are discussed: fits to fragmentation functions and multiplicity...

Dr
Helena Santos
(LIP - Lisboa)

4/12/16, 11:00 AM

QCD and Hadronic Final States

Jets provide a powerful tool for probing the dynamics of the quark-gluon plasma created in Pb+Pb collisions at the LHC. The modification of high-pT jets as they propagate in the quark-gluon plasma provides insight on structure of the plasma at short-length scale. Such modifications have been observed in a variety of measurements of single jet, dijet, photon-jet and charged-particle...

Juan Terron
(Madrid UA)

4/12/16, 11:48 AM

QCD and Hadronic Final States

The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the gluon density function of the proton.
The ATLAS collaboration has performed precise measurements of the inclusive production of isolated prompt photons in 20.3 /fb of data collected at a center-of-mass energy of 8TeV and in 3.2 /fb of data collected at a...

Ms
Olena Hlushchenko
(ZEUS, qcd working group)

4/12/16, 12:12 PM

QCD and Hadronic Final States

Following earlier measurements of prompt photon production in DIS, the
ZEUS collaboration at HERA presents measurements of new kinematic
variables. These include the azimuthal separations of the recoil
electron, the outgoing photon and an accompanying jet, and the
fraction of the incoming virtual photon energy that is taken by the
outgoing photon and the jet.

Mr
Joshua Davies
(University of Liverpool)

4/12/16, 12:36 PM

QCD and Hadronic Final States

For Deep Inelastic neutrino-proton scattering in the combination $\nu P - \bar{\nu} P$, we compute the exact $\mathcal{O}(\alpha_s^3)$ perturbative QCD corrections to the charged-current structure functions $F_2$, $F_L$ and $F_3$. These results supersede previous approximations based on the first few Mellin moments by providing all-$N$ expressions for the coefficient functions. We discuss the...

Stanislav Mikocki
(Institute of Nuclear Physics Polish Academy of Sciences)

4/12/16, 2:25 PM

QCD and Hadronic Final States

Signals of QCD instanton-induced processes are searched for in
deep-inelastic scattering (DIS) at the electron-proton collider HERA in the kinematic region defined by the Bjorken-scaling variable x > 0.001, the inelasticity 0.2< y < 0.7 and the photon virtuality 150 < Q2 < 15000 GeV^2. The search is performed using H1 data corresponding to an integrated luminosity of 350 pb^-1. Several...

Dr
Marc Pelizaeus
(Ruhr-University Bochum)

4/12/16, 2:49 PM

QCD and Hadronic Final States

The BESIII experiment at the electron positron collider BEPCII in Beijing is successfully operating since 2008 and has collected large data samples in the tau-mass region, including the world’s largest data samples at the J/ψandψ(2S) resonances. In particular decays of these two resonances provide a rich and clean environment to study hadrons consisting out of light quarks and search for...

Mr
Ryuma Hori
(KEK)

4/12/16, 3:13 PM

QCD and Hadronic Final States

A search for a narrow baryonic state in the pKS0 and \bar{p}KS0 system has
been performed in ep collisions at HERA with the ZEUS detector using an
integrated luminosity of 358 pb−1 taken in 2003-2007. The search was
performed with deep inelastic scattering (DIS) events at an ep
centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q2,
between 20 and 100 GeV2. Contrary to...

Mr
Daniele Paolo Anderle
(Institut für Theoretische Physik Universität Tübingen)

4/12/16, 3:37 PM

QCD and Hadronic Final States

With the ever increasing amount of precise data available for hadron production processes, the perturbative QCD framework is being extended to explore effects and corrections that go beyond the next-to-leading order (NLO) accuracy. Fixed order calculations at next-to-next-to-leading order (NNLO) are becoming the new necessary standard required for precision predictions and, consequently, the...

Piotr Pietrulewicz
(DESY)

4/13/16, 11:30 AM

QCD and Hadronic Final States

Exclusive 0-jet processes at hadron colliders are nowadays studied at an unprecedented precision in theory and experiment. Within the framework of Soft-Collinear Effective Theory we discuss how to incorporate massive bottom quark effects in the resummed cross section for Drell-Yan, where as specific examples for a measured exclusive observable we consider the transverse momentum of the...

Mr
Tomasz Stebel
(Jagiellonian University)

4/13/16, 11:55 AM

QCD and Hadronic Final States

In this talk a short description of the soft gluon resummation for pp->ttbarH process will be given. This is the first application of the Mellin resummation technique in a 2->3 process. The absolute threshold resummation is performed up to NLL accuracy and matched to the known NLO QCD cross-section. Results for the total cross-section at the LHC and their theoretical uncertainties will be presented.

Dr
Grigorios Chachamis
(IFT UAM-CSIC)

4/13/16, 12:20 PM

QCD and Hadronic Final States

We present a first numerical implementation of the Loop-Tree Duality (LTD) method for the direct numerical computation of multi-leg one-loop Feynman integrals. We discuss in detail the singular structure of the dual integrands and define a suitable contour deformation in the loop three-momentum space to carry out the numerical integration. Then, we apply the LTD method to the computation of...

Dr
Johannes Bellm
(IPPP, Durham Unviversity)

4/13/16, 2:20 PM

QCD and Hadronic Final States

Review of multijet merging.

James Cockburn
(University of Edinburgh)

4/13/16, 2:50 PM

QCD and Hadronic Final States

High Energy Jets (HEJ) is a novel method for organising the resummation of high energy logs in QCD to Leading Logarithmic accuracy (LL) in multi-jet production at hadronic colliders. In this talk, I will introduce the main concepts behind the approach and show how we build our exclusive predictions. I will show important results from recent LHC jet analyses. I will then discuss how the...

Gabor Veres
(CERN)

4/13/16, 3:15 PM

QCD and Hadronic Final States

Hadronic jet production at LHC is an excellent testing ground for QCD. Essential components of QCD, necessary for the description of hadronic jet data, are hard parton radiation and multiple parton interactions. The importance of these components increases for final states including multiple jets. We will show results of one observables sensitive to the hard parton radiation, which is the...

Melissa Ridel
(LPNHE-Paris)

4/13/16, 3:40 PM

QCD and Hadronic Final States

The production of multi-jet final states at hadron colliders probes pQCD at several mass scales. The processes can also be used to probe the gluon density function of the proton.
The ATLAS collaboration has measured the production of 4-jets final states in in 20.3 /fb of data collected at a center-of-mass energy of 8TeV. The measurements have been performed differentially as a function of...

Dr
Zoltan Nagy
(DESY Theory Group)

4/13/16, 4:30 PM

QCD and Hadronic Final States

Review of recent development in parton showers.

Dr
Rene Angeles Martinez
(University of Manchester)

4/13/16, 5:00 PM

QCD and Hadronic Final States

Coloumb gluons and ordering variable.

Panos Kokkas
(University of Ioannina in Ioannina, Greece)

4/13/16, 5:25 PM

QCD and Hadronic Final States

A measurement of the decorrelation of azimuthal angles between the two jets with the largest transverse momenta is presented for seven regions of leading jet transverse momentum up to 2.2 TeV. The results are compared to fixed-order predictions of perturbative quantum chromodynamics (QCD), and to simulations using Monte Carlo event generators that include parton showers, hadronization, and...

Pierre-Hugues Beauchemin
(Tufts University)

4/13/16, 5:50 PM

QCD and Hadronic Final States

The average charge and the multiplicity of charged hadrons within a jet provide new insights into the modeling of strong interactions. The jet charge can also be used to tag hadronically decaying gauge bosons and the number of charged particles within a jet provides a powerful means to distinguish gluon-initiated from quark-initiated jets.
The ATLAS collaboration has used a selection of...

Michael Rauch
(ITP, KIT)

4/13/16, 6:15 PM

QCD and Hadronic Final States

Production of electroweak bosons via vector-boson fusion (VBF) is one of the main process classes to study during the run-2 phase of the LHC. Its double-DIS-like structure gives rise to the characteristic signature of two tagging jets in the forward regions of the detectors, and distinguishes it from QCD-induced processes, which exhibit much more central jet activity. VBF processes allow to...

Prof.
Ada Solano
(Torino University and INFN)

4/14/16, 9:15 AM

QCD and Hadronic Final States

The measurements of the underlying events (UE) in the event topology of leading jet and leading track are presented. UE activities are quantified in term of particle and energy density. The UE observables are calculated in the transverse region with respect to the direction highest pT jet/track. These UE observables are measured as a as function of the pT of the leading track and jet.

David Anthony Milstead
(Stockholm University)

4/14/16, 9:40 AM

QCD and Hadronic Final States

A correct modelling of the underlying event in proton-proton collisions is important for the proper simulation of kinematic distributions of high-energy collisions.
The ATLAS collaboration extended previous studies at 7 TeV with a leading track or jet or Z boson by a new study of Drell-Yan events in 1.1 /fb of data collected at a center-of-mass energy of 7TeV. In this new study the...

Dr
Jonathan Gaunt
(Nikhef and VU)

4/14/16, 10:05 AM

QCD and Hadronic Final States

An essential part of any factorisation proof is the demonstration that the exchange of Glauber gluons cancels for the considered observable. In this talk I will show that this can be done for the double Drell-Yan process (the double parton scattering process in which a pair of electroweak gauge bosons is produced), both for the integrated cross section and for the cross section differential in...

Gilvan Augusto Alves
(Centro Brasileiro de Pesquisas Fisicas in Rio de Janeiro, Brazil)

4/14/16, 11:00 AM

QCD and Hadronic Final States

The double parton scattering (DPS) in proton-proton collisions at a center-of-mass energy of 8 TeV has been investigated using various final states. Multi-Jet, including b-jets, photon-jets as well as same-sign W bosons with each W boson decaying into muon and associated neutrino. The observables most sensitive to double parton scattering are defined and studied. A multivariate analysis is...

Dr
Mirko Serino
(Institute of Nuclear Physics, PAN, Cracow)

4/14/16, 11:24 AM

QCD and Hadronic Final States

We study both the single and double parton scattering contributions to 4 jet production in kt-factorization using off-shell matrix elements and KMR PDFs. We compare them to the collinear case and find that the expected relevance of the Double Parton Scattering contribution is tamed in the kt-factorization framework: in particular, kinematic cuts should be chosen carefully as we thoroughly discuss.

Dr
Rafal Maciula
(the Institute of Nuclear Physics PAS)

4/14/16, 11:48 AM

QCD and Hadronic Final States

Double-parton scattering (DPS) effects were discussed recently for different reactions. So far no clear and spectacular effect was observed for jet production where single-parton scattering (SPS) contributions dominate. We discuss four-jet production at the LHC. We calculate cross section for both single-parton scattering (SPS) using the ALPGEN code and for double-parton scattering (DPS) in...

Dr
Maxim Malyshev
(SINP MSU)

4/14/16, 12:12 PM

QCD and Hadronic Final States

The production of weak gauge bosons in association with heavy flavored mesons at the LHCb conditions is considered, and a detailed study of the different contributing processes is presented including single and double parton scattering mechanisms. We conclude finally, that double parton scattering dominates the production of same-sign WD states, as well as the production of W- bosons...

Mr
Iain Bertram
(Lancaster University)

4/14/16, 12:36 PM

QCD and Hadronic Final States

We use a sample of diphoton + dijet events collected using the D0 detector at the Fermilab Tevatron Collider to measure the effective cross section of double parton interactions in proton-antiproton collisions at √s=1.96 TeV. We also study the simultaneous production of two heavy quarkonia (two J/ψ or J/ψ and Υ) to extract the effective cross section of double parton interactions. We...