Excited QCD 2014

2 Feb 2014, 08:00 → 8 Feb 2014, 23:00 Europe/Sarajevo

Bjelasnica Mountain, Sarajevo

Denis Parganlija, Enila Parganlija, Francesco Giacosa (JW Goethe University), Magdalena Malek (University of Illinois at Chicago (US)), Marina Marinkovic (Humboldt University Berlin), Pedro Bicudo (IST Lisboa)

WELCOME!

Excited QCD 2014 took place on the beautiful Bjelasnica mountain located in the vicinity of the Bosnian capital Sarajevo. Bjelasnica had been a venue of the XIV Winter Olympic Games and it is situated only 30 kilometers from Sarajevo International Airport. The workshop program started on February 2 and finished on February 8, 2014, with scientific lectures taking place from February 3 to 7. Workshop participants were accomodated in Hotel Marsal, only couple of minutes by foot from the Olympic ski slopes.

We are pleased to announce that the Workshop was a topic in the local media - for a link, see here.

ABOUT THE WORKSHOP

This edition was the sixth in a series of workshops that had been previously organised in Poland, Slovakia, France and Portugal. Following the succesful meeting in 2013, the Workshop returned to Sarajevo Olympic mountains in 2014, exactly thirty years after the Games.

The workshop covered diverse aspects of QCD:

(i) QCD at low energies: excited hadrons, glueballs, multiquarks.
(ii) QCD at high temperatures and large densities: heavy-ion collisions, jets, diffraction, hadronisation, quark-gluon plasma, holography, colour-glass condensate, compact stars, applications to astrophysics.

Emphasis was placed on new developments in theory as well as the current experimental status.
Scientific atmosphere, various discussions about different topics in QCD, active participation of many young researchers and a nice environment had been the main characteristics of the previous editions and also represented the goals for the new edition.

The talks were all plenary, 25' long separated by 5' for discussions and with a coffee break of 30' every two or three talks for more discussions. An extended lunch break allowed for more discussions and for open-air activities.

VENUE

Hotel Marsal is located 1273 m above sea level, exactly below the ski slopes of Bjelasnica. The mountain itself is 2067 m high; it represented the venue for men's alpine skiing at the XIV Winter Olympics. A high-resolution picture of the mountain is available here and pictures of Bjelasnica from the '80s, '90s and presence can be found on the webpage of the Olympic Centre '84.

Recommended arrival and departure days for the workshop are February 2 and February 8, 2014 but you can also arrive, e.g., on February 1st if you find a cheaper flight (see the section on Travel Information). A map of surroundings is available here.

The cost of the accomodation is approximately 52€/night, full board is included. All participants will obtain a single room per default. If you prefer you may opt for accomodation with a second person in the room in which case the accommodation costs ~42€/night/person. Do not forget to indicate the name of the accompanying person during registration or notify us by e-mail afterwards.

Internet is available in all rooms free of charge. The Hotel accepts Visa, Master Card and American Express credit cards, cash (the local currency „marka“, euros and dollars) as well as maestro cards.


Miscellaneous information about the venue:

1. Ski map of Bjelasnica is available on the webpage of Hotel Marsal (click on the link at the bottom of the webpage). The ski pass should cost ~80€ for six days, i.e., less than 15€/day. Ski equipment (skis, ski poles, boots) can be rented in the Hotel for ~6€/day; skiing takes place between 9am and 4pm. Weather permitting, night ski also takes place from 6:30pm until 9pm every day except Sunday.

Note: to buy a ski pass, please simply go to the ski slopes cash register ("kasa") and indicate the type of pass you would like to have (day pass, seven-day pass, ...). You can also rent a snowboard + boots in the Hotel for ~7.50€/day; a sledge costs ~ 2.50€/day.

2. The Hotel has been named after Marshal Tito, the picture of whom is in the reception hall.

3. And just in case your were wondering: the Hotel has informed us that there are no mines on Bjelasnica mountain and that there have never been any. The mountain is actually very jaunty in the winter and can even serve as an artistic inspiration. Thus skiing off track is possible but not recommended due to the danger of a close encounter with a tree.


Organizing Committee

• Bicudo, Pedro
• Giacosa, Francesco
• Dr. Malek, Magdalena
• Parganlija, Denis
• Parganlija, Enila
• Marinkovic, Marina

Sunday, 2 February

08:00 → 23:00 Arrival day

Monday, 3 February

08:00 → 08:50 Breakfast

09:30 → 10:00 Hadron dynamics with vector mesons: matching theory and experiment to identify new resonances and their nature

In this talk I shall address chiral dynamics and its extension to the vector sector with the local hidden gauge approach. I shall show how some resonances are dynamically generated in the approach from meson meson and meson baryon interactions. Then will address two very recent reactions, gamma p -> K^0 Sigma^+ , with its peculiar energy dependence close to the K^* Lambda threshold, from where we deduce evidence of one of the baryon resonances predicited before, around 2030 MeV. Then I shall address the J/psi - > eta K^* K^*bar from where we find evidence of a h_1 resonance around 1830 MeV, also predicted from the vector vector interaction. Some short review of the status of the molecular states in the charm and beauty sectors will follow.

Speaker: Eulogio Oset

Slides Osetbosnia.pdf

09:30 → 12:00 Monday morning: Chair

Convener: Pedro Bicudo (IST Lisboa)

10:00 → 10:30 Recent KLOE results on hadronic physics

KLOE collected most of the data in 2004-2006, whit 2.5 fb-1 of integrated luminosity at the peak of the ϕ resonance, and about 250 pb-1 off-peak, at 1 GeV center of mass energy. Recent results obtained in light hadron physics concern the coupling of π0 and η mesons to photons, that are interesting for the effective theories based on Chiral Perturbation Theory, and for their extensions to the transition region from low energy non perturbative QCD to high energies where the perturbative QCD can be used. We measured the time-like Transition Form Factors by detecting the Dalitz decays ϕ→η e+e− and ϕ→π0 e+e− , while the coupling of the η meson to space-like photon has been obtained from γ-γ interactions (e+e− → e+e− η). These quantities are also interesting for the evaluation of the Light-by-Light scattering contribution to the anomalous magnetic moment of the muon. With gamma-gamma interactions we detected also the π0 π0 final state to study the production of the σ(500) scalar meson. Also a new measurement of η →π+π−π0 Dalitz plot will be presented, of interest for the determination of fundamental parameters like the light quark masses. The prospects for the new KLOE-2 data-taking aiming to collect 5 fb-1 in the next three years will be reviewed

Speaker: Paolo Gauzzi (INFN)

Slides pgauzzi_exqcd14.pdf

10:30 → 11:00 Coffee break

11:00 → 11:30 The $\Sigma_{\pi N}$ Term, Chiral Multiplet Mixing and Hidden Strangeness in the Nucleon

The nucleon $\Sigma$ term's large "observed" value (> 55 MeV) has long been interpreted as a sign of hidden strangeness in the nucleon. We have calculated the $\Sigma_{\pi N}$ term on the basis of mixing of chiral multiplets, and using known constraints on the current quark masses $m_{u}^{0}, m_{d}^{0}$ and the flavor-singlet and isostriplet axial couplings. We show that the $[(1,1/2)\oplus (1/2,1)]$ chiral multiplet, that is necessary for the reproduction of the isotriplet axial coupling, makes a contribution enhanced by a factor of $\frac{19}{3}\simeq 6.33$, due to $SU_L(2) \times SU_R(2)$ algebra, that leads to $\Sigma_{\pi N} \geq \left(1 + \frac{16}{3} \sin^2 \theta \right){3 \over 2} \left(m_{u}^{0} + m_{d}^{0}\right) = 60$ MeV, in general accord with ``experimental'' values of $\Sigma_{\pi N}$. The chiral mixing angle $\theta$ is given by $\sin^2\theta = \frac{3}{8}\left(g_A^{(0)} + g_A^{(3)}\right)$, where $g_A^{(0)} = 0.33 \pm 0.08$, or $0.28 \pm 0.16$, and $g_A^{(3)} = 1.267$, are the flavor singlet and the isotriplet axial couplings, respectively. These results show there is no need for $q^4 {\bar q}$ components, and in particular, no need for an $s \bar s$ component in the nucleon.

Speaker: Veljko Dmitrasinovic (Institute of Physics Belgrade)

Slides ExcQCD2014-dmitrasinovic.pdf

11:30 → 12:00 Recent results from HERA on the proton structure

ew precision measurements of the double-differential inclusive neutral-current cross section, measured with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV in e+p and e-p collisions are shown. They span the kinematic domain of high momentum transfer Q^2>650 GeV^2 and high Bjorken-x~1. Using the HERA data collected at three different centre-of-mass energies, both the collaborations H1 and ZEUS have updated their measurements of the longitudinal structure function F_L. The structure function is measured in the kinematic region of momentum transfer 1.5<Q^2<800 GeV^2 and Bjorken-x 3x10^-4 <x<0.03. The measurements are compared to predictions from the Standard model, based on a variety of parton density functions.

Speaker: Natasa Raicevic (University of Montenegro)

Slides Raicevic_Excited_QCD_2014.pdf

12:00 → 16:30 Lunch/Ski/Discussion

16:30 → 17:00 Low vs high-lying modes for hadron mass generation

We study the effect of the chiral symmetry breaking low-lying modes of the Dirac operator and of the higher-lying modes on the hadron mass generation and on symmetries of hadrons in lattice QCD simulations.

Speaker: Leonid Glozman (Graz U)

Slides leonidglozmanexcitedqcd2014.pdf

16:30 → 19:00 Monday afternoon: Chair

Convener: Eulogio Oset

17:00 → 17:30 Dense nuclear matter in neutron stars

I will discuss recent measurements of neutron stars masses and radii and their implications for the equation of state of high density matter. I will focus in particular on the possible appearance of delta resonances, hyperons and strange quark matter and the dynamics of the formation process of such "exotic" degrees of freedom. Finally, I will present diffusion simulations of the cooling of newly formed strange stars.

Speaker: Giuseppe Pagliara

Slides pagliara-sarajevo.pdf

17:30 → 18:00 Coffee break

18:00 → 18:30 Vortices and chiral symmetry breaking

We analyze the creation of near-zero modes from would-be zero modes of various topological charge contributions from classical center vortices in $SU(2)$ lattice gauge theory. We show that colorful spherical vortex and instanton configurations have very similar Dirac eigenmodes and also vortex intersections are able to give rise to a finite density of near-zero modes, leading to chiral symmetry breaking via the Banks-Casher formula. We discuss the influence of magnetic vortex fluxes on quarks and how center vortices may break chiral symmetry.

Speaker: Manfried Faber (Vienna UT)

Slides faberExQCD14.pdf

18:30 → 19:00 Many-flavour QCD and the conformal window

As the number of flavours in QCD is increased beyond some threshold, chiral symmetry is restored and long-distance physics becomes scale invariant. The region of parameter space in which this happens is called "conformal window". The phenomenology of theories in the conformal window or close to it is very different from real-world QCD, and clearly shows how rich gauge theories can be. As these theories are inherently non-perturbative, lattice simulation provide a unique setup to investigate them from first principles. In this talk I will review the main results and open questions in this field, the challenges ahead, and the techniques used.

Speaker: Agostino Patella (CERN)

Slides patella.pdf

19:30 → 21:25 Dinner

Tuesday, 4 February

08:00 → 09:00 Breakfast

09:30 → 10:00 The PANDA experiment at FAIR

The PANDA experiment is one of the key components of the future "Facility for Antiproton and Ion Research" at Darmstadt. Its goal is to study the features of the strong force in the transition region between perturbative and non-perturbative QCD. Therefore it utilizes the phase space cooled antiproton beam with a beam momentum between 1.5 GeV/c and 15 GeV/c to do precision measurements in the charmonium mass range. The physics program of PANDA covers a wide field of different topics: charmonium and charmed/multi-strange baryon spectroscopy, the search for hybrids and glueballs as well as the study of electromagnetic processes, single and double hypernuclei and hadrons in nuclear matter. To do these demanding measurements a complex experimental setup is needed using state-of-the-art detector technologies. During this presentation an overview of the physics program as well as the experimental setup will be given.

Speaker: Tobias Stockmanns (Forschungszentrum Jülich GmbH)

Slides ExcitedQCD_Stockmanns.pptx

09:30 → 12:00 Tuesday morning: Chair

Convener: Marina Marinkovic (Humboldt University Berlin)

10:00 → 10:30 Exotic Hadron Spectroscopy

Since ten years experiments have been observing a host of exotic states decaying into heavy quarkonia. The interpretation of most of them still remains uncertain and, in some cases, controversial, notwithstanding a considerable progress has been made on the quality of the experimental information available and a number of ideas and models have been put forward to explain the observations. In this talk we will expose the state-of-the-art of exotic spectroscopy, and will review the most promising theoretical interpretations.

Speaker: Alessandro Pilloni (Sapienza U.)

Slides exotic_spectroscopy.pdf

10:30 → 11:00 Coffee break

11:00 → 11:30 Exotic Hadrons and Large Nc QCD

Exotic hadrons are those which cannot be described in a naive quark model. This talk discusses possible insights the large Nc limit of QCD can give us about exotics. The focus will be on tetraquark states. One key feature of the analysis is the fact there is more than one way to extrapolate to the large Nc limit.

Speaker: Thomas Cohen (University of Maryland)

Slides Exotics_and_Large_Nc.pdf

11:30 → 12:00 $a_{0}(980)$ as a dynamically generated resonance in the extended linear sigma model

We study basic properties of scalar hadronic resonances within the so-called extended linear sigma model (eLSM), which is an effective model of QCD based on chiral symmetry and dilatation invariance. In particular, we focus on the mass and decay width of the isovector state $a_{0}(1450)$ and perform a numerical study of the propagator pole(s) on the unphysical Riemann sheets. Here, the $a_{0}(1450)$ is understood as a seed state explicitly included in the eLSM -- this is in fact not true for the corresponding resonance below 1 GeV, the $a_{0} (980)$, which is sometimes interpreted as a kaonic (i.e., dynamically generated) bound state. In our work we want to clarify if the yet not included $a_{0}(980)$ can be found as a propagator pole generated by hadronic loop contributions. From such an investigation one could learn more about the general dependence of the eLSM -- and effective field models in general -- on strongly coupled hadronic intermediate states, possibly giving new insight into the low-energy regime, scalar resonances and both its theoretical description and physical interpretation.

Speaker: Thomas Wolkanowski (Johann Wolfgang Goethe-Universität)

Slides Sarajevo2014.pdf

12:00 → 16:30 Lunch/Ski/Discussion

16:30 → 17:00 Dynamic Holographic QCD

I present a simple AdS/QCD model in which the formation of the chiral condensate is dynamically determined. The gauge dynamics is input through the running of the quark bilinear's anomalous dimension, gamma. The condensate provides a dynamically generated infra-red wall in the computation of mesonic bound state masses and decay constants. As an example, I use the model, with perturbative computations of the running of gamma, to study SU(3) gauge theory with a continuous number of quark flavours, Nf. We follow the behaviour of the spectrum as we approach the conformal window through a walking gauge theory regime. The phase diagram of the theory is also computable in this model.

Speaker: Nick Evans (U)

Slides EvansSarajevo14.pdf

16:30 → 19:00 Tuesday afternoon: Chair

Convener: Francesco Giacosa (JW Goethe University)

17:00 → 17:30 Scalar photoproduction on the proton at CLAS and GlueX energies

In this work we present the results of a theoretical analysis of the data on photoproduction of $f_0(980)$ meson in the laboratory photon energy between 3.0 and 3.8 GeV. A comparison is done to the measurements performed by the CLAS collaboration at JLab accelerator for the exclusive reaction $\gamma p\rightarrow pf_0(980)$. In the analysis the partial S-wave differential cross section is described by a model based on Regge approach with reggeized exchanges and distinct scenarios for the $f_0(980)\rightarrow V\gamma$ coupling are considered. It is shown that such a process can provide information on the resonance structure and production mechanism. We also present the results for GlueX energies.

Speaker: Mario Luiz L da Silva (Universidade Federal de Pelotas)

Slides DaSilvaExcited_qcd.pdf

17:30 → 18:00 Coffee break

18:00 → 18:30 Light meson production in nucleon-nucleon reactions

We study the production of mesons in nucleon-nucleon reactions at center-of-mass momenta of a few GeV using an $N_f=2$ linear sigma model, extended by including the $N_f=2$ multiplets of (pseudo-) scalar and (axial-) vector mesons and a doublet of the nucleon together with its chiral partner (the $N^*(1535)$ or $N^*(1650)$ resonance).

Speaker: Khaled Teilab (Frankfurt U)

Slides KhaledTeilab_Sarajevo.pps

18:30 → 19:00 Low x evolution equation for proton Green function

The derivation, properties, and application of the low x evolution equation for proton Green function are discussed.

Speaker: Andrey Grabovskiy (Budker Institute of Nuclear Physics (RU))

Slides AndrejSarajevo2014.pdf

19:30 → 21:25 Dinner

Wednesday, 5 February

08:00 → 09:00 Breakfast

09:30 → 10:00 N =4 super Yang-Mills plasma

Motivated by the AdS/CFT duality, we study the N=4 super Yang-Mills plasma in the regime of weak coupling and compare it to the QCD plasma. Collective excitations and collisional processes are discussed. Since the Keldysh-Schwinger approach is used, the collective excitations in both equilibrium and non-equilibrium plasma are under consideration. The dispersion relations of gluon, fermion, and scalar fields are found in the Hard Loop Approximation and the corresponding effective action is given. The binary collisional processes, which occur at the lowest nontrivial order of the coupling constant, are reviewed and then the transport properties of the plasma are discussed. For more see: A. Czajka and St. Mrowczynski, Phys. Rev. D 86, 025017 (2012).

Speaker: Stanislaw Mrowczynski (National Center of Nuclear Reserach, Warsaw, Poland)

Slides Mrowczynski.pdf

09:30 → 12:00 Wednesday morning: Chair

Convener: Tereza Mendes (University of Sao Paulo)

10:00 → 10:30 Ghosts in Nonequilibium Quark-Gluon Plasma

The quark-gluon plasma at the early stage of relativistic heavy-ion collisions is out of equilibrium. The Keldysh-Schwinger formalism provides a natural framework to describe such a plasma, in particular when the plasma is weakly coupled and perturbative methods are applicable. However, a perturbative computation of various QCD characteristics requires Faddeev-Popov ghosts to cancel unphysical degrees which are present in a wide class of covariant gauges. The question thus arises how to introduce the ghosts for non-equilibrium QCD. Using the functional methods, we derive a relation analogous to the Slavnov-Taylor identity which expresses the ghost propagator of the Keldysh-Schwinger formalism through the gluon one. Then we show that the ghost propagator obtained in this way allows one to construct a gauge invariant perturbative expansion of various characteristics of non-equilibrium quark-gluon plasma.

Speaker: Alina Czajka (UJK)

Slides CzajkaSarajewo-Ghosts.pdf

10:30 → 11:00 Coffee break

11:00 → 11:30 The CBM heavy-quark program

The Compressed Baryonic Matter (CBM) experiment at FAIR is designed to explore the QCD phase diagram in the region of high baryon densities and moderate temperatures. The key CBM observables include particles containing hidden charm – J/psi and Psi’, open charm – D0, D+ , D* and Lambda_c, low-mass vector mesons decaying into leptons and multi-strange hyperons. Particularly demanding is the measurement of open charm particles with very low multiplicities, which is based on the real time selection of displaced vertices with an accuracy of about 50 μm. In the talk we discuss the problems of the detection of heavy-quark particles in fixed target experiments with relativistic heavy ion collisions.

Speaker: Iouri Vassiliev (GSI Helmholtzzentrum für Schwerionenforschung)

Slides I.Vassiliev_CBM_HQP_EQCD2014_m.ppt

11:30 → 12:00 Charm production at HERA

The copious production of charm quarks at HERA has yielded a detailed understanding of QCD dynamics, the only measure of the charm contribution to the proton structure, as well as measurements of the charm mass and the fragmentation parameters of charmed hadrons. Several measurements of charm production in deep inelastic scattering, using different decay modes, are presented, both new individual measurements from the H1 and ZEUS collaborations, as well as combined data. These provide a powerful vindication of the form of the gluon density in the proton derived from scaling violations of inclusive deep inelastic scattering data. A QCD fit to the charm data leads to a measurement of the charm mass and also provides precise predictions for e.g. W and Z production at the LHC. Additionally, fragmentation fractions to the ground state charm hadrons are compared to e+e- data and previous HERA results. The data have a precision similar to that of the e+e- data and support the hypothesis that fragmentation is independent of the production process.

Speaker: Uri Karshon (Weizmann.Institute of Science)

Slides karshoncharm.pdf

12:00 → 16:30 Lunch/Ski/Discussion

16:30 → 17:00 Magnetic Phenomena in holographic QCD

I will review various effects connected to magnetic fields in the context of holographic QCD. These will include magnetic catalysis, new phases of matter and new phase transitions.

Speaker: Gilad Lifschytz (University of Haifa at Oranim)

Slides Excited_QCD_2014.pdf

16:30 → 19:00 Wednesday afternoon: Chair

Convener: Agostino Patella (CERN)

17:00 → 17:30 The nature of diffractive production at HERA

Data in which a proton is tagged along the beampipe after the primary interaction represents the cleanest way to measure diffraction. Data from both H1 and ZEUS collaborations on inclusive diffractive deep inelastic scattering, with a tagged proton, have been combined. Inclusive diffractive deep inelastic scattering can be considered as the exchange of a colourless object and is amenable to QCD fits in which the structure of this object, sometimes called a Pomeron, is determined. Given such processes are expected to factorise, such a Pomeron structure can be used to predict the rates of jet production in e.g. diffractive photoproduction. The comparison of jet data with the predictions of next-to-leading order QCD are discussed in the context of factorising breaking. Another way to study diffraction is through the production of vector mesons which is also characterised by a colourless exchange with the proton which in lowest order QCD is realised as a colourless gluon pair. Therefore consideration of the dependence of the J/psi cross section on the photon-proton centre-of-mass energy is related to the rise of the square of the gluon density towards low values of Bjorken x. Comparisons of HERA data with such theories and other data are presented.

Speaker: Grzegorz Pawel Gach (AGH University of Science and Technology (PL))

Slides Diffraction.pdf

17:30 → 18:00 Coffee break

18:00 → 18:30 AdS/CFT and the axial sector of large-N Yang-Mills Theory

In holographic models of large-N gauge theories, the pure-glue axial sector is described in terms of a massless pseudoscalar field, dual to the topological density operator. I will outline how this duality can be used to compute observables such as axial glueball masses and decay constants, as well as correlation functions and transport coefficients in the axial sector. I will focus especially on phenomenological holographic models, and discuss potential connections with observation and lattice results.

Speaker: Francesco Nitti

Slides Nitti-eQCD14.pdf

18:30 → 19:00 Applications of the Sakai-Sugimoto Model to Hadron Spectroscopy

Some aspects of the Sakai-Sugimoto model, a holographic top-down approach capturing many features of quantum chromodynamics, are presented. Meson spectra, finite-temperature and finite-baryon-density effects are discussed. Furthermore, the description of glueballs within this framework is revisited and possible directions for future developments are discussed.

Speaker: Frederic Brünner (Vienna UT)

Slides GlueballsEQCD14.ppt

19:30 → 21:25 Dinner

Thursday, 6 February

08:00 → 09:00 Breakfast

09:00 → 09:30 Regge trajectory of the f0(500) resonance from a dispersive connection to its pole

Our results on obtaining the Regge trajectory of a resonance from its pole in a scattering process and from analytic constraints in the complex angular momentum plane will be presented. The method, suited for resonances that dominate an elastic scattering amplitude, has been applied to the rho(770) and the f0(500) resonances. Whereas for the former we obtain a linear Regge trajectory, characteristic of ordinary quark-antiquark states, for the latter we find a non-linear trajectory with a much smaller slope at the resonance mass. We also show that if a linear trajectory with a slope of typical size is imposed for the f0(500), the corresponding amplitude is at odds with the data.

Speaker: Jose R. Pelaez (Universidad COmplutense)

Slides Pelaez.pptx

09:00 → 12:00 Thursday morning: Chair

Convener: Thomas Cohen (University of Maryland)

09:30 → 10:00 Why f0(500) must be narrower?

Recent works on the pion-pion scattering amplitudes done with use of one-subtracted dispersion relations [1] led to large modification of the f0(500) parameters, especially its width [2]. Immediately it led to long waited significant changes in the Particle Data Group Tables (Particle Listings and "Note on scalar mesons below 2 GeV" in [3]). Such changes resulted in the need to redefine a number of amplitudes used in the theoretical and experimental works. Sometimes, however, their authors doubt the necessity of introducing such changes and even question correctness of analyses confirming new parameters f0(500). Making example of reanalysis of such amplitudes and showing why dispersion relations with imposed crossing symmetry need narrower f0(500) one can easily once again prove the validity of the changes in the f0(500) parameters. [1] "The Pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV", R. Garcia-Martin, R. Kaminski, J. R. Pelaez, J. Ruiz de Elvira and F.J. Yndurain, Phys. Rev. D83, 074004 (2011) [2] "Precise determination of the f0(600) and f0(980) pole parameters from a dispersive data analysis" R. Garcia-Martin, R. Kaminski, J.R. Pelaez, J. Ruiz de Elvira Phys. Rev. Lett. 107 (2011) 072001 [3] J. Beringer et al. (Particle Data Group), Phys. Rev. D86, 010001 (2012).

Speaker: Robert Kaminski (Institute of Nuclear Physics PAN)

Slides RobertKaminskiTalkExcitedQCD2014.pdf

10:00 → 10:30 Coffee break

10:30 → 11:00 BESIII latest results

The latest result by BES III at BEPC are presented.

Speaker: Marco Maggiora (Univ. + INFN)

Slides 20140207.ExQCD.BESIII.Maggiora.v1.pdf

11:00 → 11:30 Recent BaBar studies of conventional and exotic quarkonium states

The B factories provide a unique playground for the study of the properties of conventional and exotic quarkonium states, We report on a variety of recent results obtained using the full data set collected with the BaBar detector at the PEPII e+e- collider. In particular, we present measurements of the prompt production of J/psi or psi(2S) in association with a second charmonium state at a center-of-mass energy of 10.58 GeV, searches for exotic neutral and charged charmonium-like states, studies of charmonium production in two-photon fusion and initial state radiation processes, as well as studies of radiative transitions between bottomonium states.

Speaker: Guy Wormser (LAL Orsay)

Slides excited_qcd_2014_gw.pptx

11:30 → 12:00 Studying and removing effects of fixed topology

At small lattice spacing, or when using e.g. overlap fermions, lattice QCD simulations tend to become stuck in a single topological sector. Physical observables, e.g. hadron masses, then differ from their full QCD counterparts by 1/V corrections, where V is the space-time volume. These corrections can be calculated order by order using the saddle point method. We calculate all corrections proportional to 1/V^2 and 1/V^3 and test the resulting equations for several models: an analytically solvable quantum mechanical model, the Schwinger model, and pure SU(2) Yang Mills theory

Speaker: Arthur Dromard (Goethe University)

Slides DromardExcited_QCD_2014.pdf

12:00 → 16:30 Lunch/Ski/Discussion

16:30 → 17:00 Hot SU(2) Glue around Deconfinement

We investigate on the lattice the properties of electric and magnetic gluon propagators for finite-temperature SU(2) theory around the deconfinement transition. Special care is taken to handle the very strong systematic effects that arise in the critical region.

Speaker: Tereza Mendes (University of Sao Paulo)

Slides mendes_eQCD14.pdf

16:30 → 19:00 Thursday afternoon

Convener: Jose R. Pelaez (Universidad COmplutense)

17:00 → 17:30 Approaching the chiral point in two-flavour lattice simulations

We investigate the behaviour of the pion decay constant and the pion mass in two-flavour lattice QCD, with the physical and chiral points as ultimate goal. Measurements come from the ensembles generated by the CLS initiative using the O(a)-improved Wilson formulation, with lattice spacing down to about 0.05 fermi and pion masses as low as 190 MeV. The applicability of SU(2) chiral perturbation theory is investigated, and various functional forms, and their range of validity, are compared. Among the studied observables are also some related to a third, heavier valence quark (``strange''), which enables examination of kaon-related observables.

Speaker: Stefano Lottini (D)

Slides excited2014_Lottini.pdf

17:30 → 18:00 Coffee break

18:00 → 18:30 The role of hadronization processes to determine the fragmentation functions

We are studying fragmentation functions (FFs) applying different hadronization processes and we are determining FFs from global analysis on single-inclusive electron-positron annihilation (SIA) and semi-inclusive deep inelastic scattering (SIDIS) data at NLO. We perform an improvement to the FFs of pion and kaon at next-to-leading order (NLO), including very recently single-inclusive electron-positron annihilation data from BABAR and Belle at Q = 10.54 GeV and Q = 10.52 GeV, respectively. Our main purpose is to show that imposing these new data in our analysis how much improve the fragmentation functions of pion and kaon at NLO.

Speaker: Maryam Soleymaninia (Semnan university)

Slides Soleymaninia_Excited_QCD_2014.pptx

18:30 → 19:00 Target mass and higher twist effects in polarized deep-inelastic scattering

We perform a fit to all available experimental data of polarized structure functions in the framework of perturbative QCD, at next-to-leading order (NLO) approximation. We include target mass correction and higher twist effects on our fitting procedure and study their effects on physically interesting quantities. Nuclear polarized structure functions are described based on our fit result. Moreover, sum rules are derived and compared with available theoretical and experimental results.

Speaker: Sara Taheri Monfared (Semnan University)

Slides Taheri-Excited_QCD_2014.pptx

19:30 → 21:25 Conference Dinner

Friday, 7 February

08:00 → 09:00 Breakfast

09:30 → 10:00 Effects of divergent ghost loops on the Green's functions of QCD

I discuss certain characteristic features encoded in some of the fundamental QCD Green's functions, whose origin can be traced back to the (Landau gauge) nonperturbative masslessness of the ghost field. Specifically, the ghost loops that contribute to these Green's functions display infrared divergences, akin to those encountered in the perturbative treatment, in contradistinction to the gluonic loops, whose perturbative divergences are tamed by the dynamical generation of an effective gluon mass. In d=4, the aforementioned divergences are logarithmic, thus causing a relatively mild impact, whereas in d=3 they are linear, giving rise to enhanced effects. In the case of the gluon propagator, these effects do not interfere with its finiteness, but make its first derivative diverge at the origin, and introduce a maximum in the region of infrared momenta. The three-gluon vertex is also affected, and the induced divergent behavior is clearly exposed in certain special kinematic configurations, usually considered in lattice simulations; the sign of the corresponding divergence is unambiguously determined. The picture that emerges is finally compared to the available lattice data.

Speaker: Daniele Binosi (ECT* Fondazione Bruno Kessler)

Slides Binosi.pdf

09:30 → 12:00 Friday morning: Chair

Convener: Leonid Glozman

10:00 → 10:30 Probing nucleons with photons at the quark level

I will review recent progress on nucleon form factor calculations and nucleon Compton scattering in the Dyson-Schwinger approach. By specifying a quark-gluon interaction kernel, the framework allows for a systematic calculation of hadron masses, form factors and nucleon-photon scattering processes from the quark-gluon level. I will present results for a variety of observables and discuss the current limitations and future directions of the approach.

Speaker: Gernot Eichmann

Slides Eichmann.pdf

10:30 → 11:00 Coffee break

11:00 → 11:30 Non-perturbative features of the three-gluon vertex in Landau gauge

Self-consistent solutions for the three-gluon vertex in Landau gauge QCD using a Bose-symmetric truncation of Dyson-Schwinger equations are presented. A detailed discussion of the symmetry properties of the vertex and its basis decomposition is made, together with suitable fits for phenomenological applications. Increasing the number of light quark flavors leads to a qualitative change of the vertex properties in a way as expected for the conformal window.

Speaker: Milan Vujinovic (Karl-Franzens University, Graz)

Slides Excited_QCD_MV.pdf

11:30 → 12:00 Infrared behaviour of propagators and running coupling in the conformal window of QCD

Using the Dyson-Schwinger approach we investigate QCD with a relatively large number of quark flavors in the chiral limit. A self-consistent treatment of the corresponding propagator equations enables us to study unquenching effects directly via the quark loop diagram in the gluon equation. Above the critical number of fermion flavors the non-perturbative running coupling develops a plateau over a wide momentum range. Correspondingly, the propagators follow a power law behavior in this momentum range indicating conformal behavior. Our value $N_f^{crit}=4.5$ is strongly sensitive to the details of the quark-gluon vertex calling for more detailed investigations in future studies.

Speaker: Markus Hopfer (University of Graz)

Slides 2014_ExcitedQCD_Hopfer.pdf

12:00 → 16:30 Lunch/Ski/Discussion

16:30 → 19:00 Friday afternoon: Chair

Convener: Denis Parganlija

16:30 → 17:00 Understanding confinement via instanton-monopoles

The problem of confinement is a long lasting problem in physics. Recently however there has been great progress in understanding confinement in a large class of locally 4D supersymmetric and non-supersymmetric theories with the help of instanton-monopoles. I will discuss how these can help us understand confinement in pure YM and QCD.

Speaker: Tin Sulejmanpasic (Regensburg U)

Slides Sulejmanpasic.pdf

17:00 → 17:30 Intriguing relations between the LECs of Wilson $\chi$-PT and spectra of the Wilson Dirac operator

We discuss the behavior of the spectral densities of the non-Hermitian Wilson Dirac operator and we derive interesting relations for the leading order physical and Wilson LECs of Wilson $\chi$-PT. These relations can be used to determine the LECs from lattice simulations.

Speaker: Savvas Zafeiropoulos (Universite Blaise Pascal)

Slides Zafeiropoulos_ExcitedQCD14.pdf

17:30 → 18:00 Coffee break

18:00 → 18:30 Model-independent analysis of scenarios with vector-like quarks

Vector-like quarks are predicted in various scenarios of new physics, and their peculiar signatures from both pair and single production have been already investigated in detail. However no signals of vector-like quarks have been detected so far, pushing limits on their masses above 600-700 GeV, depending on assumptions on their couplings. Experimental searches consider specific final states to pose bounds on the mass of a vector-like quark, usually assuming it is the only particle that contributes to the signal of new physics in that specific final state. However, realistic scenarios predict the existence of multiple vector-like quarks, possibly with similar masses. The reinterpretation of mass bounds from experimental searches is therefore not always straightforward. I will describe a method to perform a combined analysis of experimental searches, considering different final states, to determine the exclusion limit of scenarios where any number of vector-like quarks can contribute to the signal of new physics, as it is usually the case with realistic models of new physics.

Speaker: Luca Panizzi (University of Southampton)

Slides VLF.pdf

18:30 → 19:00 Higgs discovery status from ATLAS

An οverview of the Higgs boson search latest results in the ATLAS experiment at the LHC, after the discovery, is presented. The various decay channels in the context of the Standard Model and BSM searches are discussed. Latest results on the properties of the boson are given, with focus on the mass measurement, spin, parity and production mechanisms.

Speaker: Kalliopi Iordanidou (UOA (GR) / Brookhaven National Laboratory (US))

Slides K_Iordanidou.pdf

19:00 → 19:10 Closing Remarks

Convener: Organizers

19:30 → 00:00 Dinner

Saturday, 8 February

08:00 → 23:00 Departure