Excited QCD 2012

6-12 May 2012
Peniche, Portugal
Europe/Lisbon timezone
Home > Contribution List
Displaying 44 contributions out of 44
Lattice QCD is a first-principle computational tool to describe the properties of hadron spectrum and decay modes, which allows for precision tests of the Standard Model. The algorithm of choice for lattice QCD simulations is known as the Hybrid Monte Carlo (HMC) algorithm. I am going to discuss recent algorithmic and implementation improvements which lead to a better scaling of the new highly opt ... More
Presented by Marina MARINKOVIC on 10 May 2012 at 11:30
We present the new results of the Wuppertal-Budapest lattice QCD collaboration on flavor diagonal and non-diagonal quark number susceptibilities with 2+1 staggered quark flavors, in a temperature regime between 120 and 400 MeV. A Symanzik improved gauge and a stout-link improved staggered fermion action is utilized; the light and strange quark masses are set to their physical values. Lattices ... More
Presented by Claudia RATTI on 10 May 2012 at 10:00
The interaction of particles is one of the fundamental questions in Physics. We decided to study the interaction between a gluon gas produced at the onset of ‘Heavy Ion Collisions’, and forming pions and other hadrons. To do so, we develop a code for Graphics Processing Units, using CUDA as program language, based on the CPU code ‘Boltzmann Approach for Many Parton Scattering (BAMPS)’ dev ... More
Presented by Ulrike EILHAUER on 7 May 2012 at 19:00
We present the extension of the globally chirally invariant N_f=3 linear sigma model with vector and axial-vector degrees of freedom to N_f=4. We calculate the masses of axial- vector mesons from the extended model and present it.
Presented by Walaa ESHRAIM on 9 May 2012 at 11:00
In this work we compute the color fields in the mediator plane between a static quark and a static antiquark using quenched lattice QCD. In special, we see the effect of the quark-antiquark distance on this fields. To obtain this results an improved multihit technique is developed and an extend smearing technique is used. The results for the fields are fitted with different models and in particu ... More
Presented by Marco CARDOSO on 10 May 2012 at 19:00
Chiral symmetry breaking in Quantum Chromodynamics is associated with the low lying spectral modes of the Dirac operator according to the Banks-Casher relation. Here we study how removal of a variable number of low lying modes from the valence quark sector affects the masses of the first excited states of baryons and mesons in two flavor lattice QCD.
Presented by Mr. Mario SCHROECK on 7 May 2012 at 11:30
The new international accelerator facility FAIR under construction in Darmstadt aims at studying matter at atomic, nuclear, and hadronic levels. I will present different aspects of the current status of the Facility for Antiproton and Ion Research. I will discuss the focus of the experiments at FAIR and the associated theory in hadron physics, nuclear structure and compressed nuclear matter physi ... More
Presented by diana NICMORUS on 11 May 2012 at 18:30
Recent large-volume lattice simulations have established that, in the Landau gauge, the gluon propagator is infrared-finite. The most natural way to explain this observed finiteness is the generation of a nonperturbative, momentum-dependent gluon mass. Such a mass may be generated without compromising the gauge-invariance of the fundamental QCD Lagrangian by employing the famous Schwinger me ... More
Presented by David IBáñEZ GIL DE RAMALES on 9 May 2012 at 10:00
Recent work on in-medium hadronization in the non-equilibrated fragmentation process has been followed up by studies on bound state formation in the equilibrated deconfined matter as described by lattice QCD. Through the comparison to PNJL model calculations we find evidence for an extended phase of mixed degrees of freedom. The extracted hadron formation probability exhibits flavor and baryo ... More
Presented by Rene BELLWIED on 10 May 2012 at 17:00
We apply hydrodynamic model calculations to predict soft particle observables in relativistic heavy-ion collisions. Results of simulations of a 3+1D viscous hydrodynamic model are presented. A satisfactory description of transverse momentum spectra, HBT radii, and elliptic and triangular flows in heavy-ion collisions at RHIC and the LHC is obtained. Most advanced simulations of the model are p ... More
Presented by Piotr BOZEK on 8 May 2012 at 12:00
When generalizing recent various quantum mechanical models of $c-\bar{c}$ states to Quantum Filed theoretical approach based on BSE one is faced to the solutions that do not exist in non-relativistic limit. Mainly, there is unexpected doubling of the spectrum when comparing to the spectrum expected or known from the experiments as well as the ones known from the solution of the Schroedinger e ... More
Presented by Mr. Vladimir SAULI on 11 May 2012 at 12:00
Recently, we have successfully described [1] the controversial X(3872) charmonium resonance as a normal axial-vector ($J^{PC}=1^{++}$) $c\bar{c}$ state, but non-perturbatively unitarised and mass-shifted owing to several OZI-allowed and OZI-suppressed decay channels. Nevertheless, many authors still consider the X(3872) a meson-meson molecule, due to its very close proximity to the $D^0D^{*0}$ th ... More
Presented by Susana COITO on 7 May 2012 at 17:30
Presented by Edmond IANCU on 8 May 2012 at 17:00
We explore the performance of CUDA in performing Landau gauge fixing in Lattice SU(3), using the steepest descent method with Fourier acceleration. The code performance was tested in a Tesla C2070, Fermi architecture. We also present a study of the string tension at finite temperature in the confined phase. The string tension is extracted from the colour averaged free energy and the color si ... More
Presented by Nuno CARDOSO on 10 May 2012 at 17:30
Presented by Francesco NITTI on 8 May 2012 at 11:30
Presented by Krzysztof WOZNIAK on 7 May 2012 at 10:00
Results from a variety of QCD and Heavy Ion physics analyses are presented using pp and PbPb collision data collected by the CMS experiment. The data distributions are compared with the predictions of Monte Carlo event generators and with perturbative QCD calculations.
Presented by Bora ISILDAK on 7 May 2012 at 09:30
ALICE is the LHC experiment dedicated to the study of heavy-ion collisions. Its features also make it an ideal detector for QCD studies in pp collisions. Thanks to its excellent particle identification capabilities and low material budget, ALICE can measure hadron and lepton production over a wide momentum range both in pp and in Pb-Pb collisions. In this talk we review recent QCD results, ... More
Presented by Barbara GUERZONI on 7 May 2012 at 09:00
The PHENIX experiment has produced an extensive array of measurements in heavy ion collisions in order to study the created strongly interacting medium. This medium is seen to modify the properties of many global and high-momentum observables; a strong suppression relative to that expected from p+p collisions is observed. The medium forms after the initial hard-scattering of partons, which they ... More
Presented by Dr. Aneta IORDANOVA on 10 May 2012 at 09:00
Contrary to widespread belief, there are not too many observed mesonic resonances to be accounted for by normal quark-antiquark states, which is the usually invoked argument to justify the introduction of (crypto)exotic configurations. The reasons why newly detected mesonic enhancements often seem to be incompatible with $q\bar{q}$ states can be manifold: (i) the underlying confining potentia ... More
Presented by George RUPP on 7 May 2012 at 17:00
We consider the $(2+1)$ flavor Polyakov Quark Meson Model (PQM) and study the effect of including fermion vacuum fluctuations on the thermodynamics and phase diagram. The variation of the thermodynamic quantities across the phase transition region becomes smoother. This results in better agreement with the lattice QCD (LQCD) data. The critical end point is pushed into higher values of the chemic ... More
Presented by Mr. Sandeep CHATTERJEE on 8 May 2012 at 09:30
In the context of high density QCD systems, the high occupancy numbers make it convenient to consider the strong classical fields as the appropriate degrees of freedom. High energy collision experiments are particularly sensitive to the correlators of these multiple sources by means of the multiple scattering undergone by the produced particles. By carefully studying the color structure of several ... More
Presented by Fabio DOMINGUEZ on 11 May 2012 at 09:30
Recent progress in the calculation of Next-To-Leading order observables in perturbative QCD are presented, with a focus on results from so-called unitarity techniques for high multiplicity processes.
Presented by Daniel MAITRE on 7 May 2012 at 18:30
We study positive and negative parity states of the nucleon, with particular interest in the parity reversal pattern of the Roper resonance. We investigate the isospin 1/2 channel of the pion-nucleon scattering on the lattice, including meson-nucleon interpolators. The distillation method makes the computation of disconnected diagrams affordable, while the variational method is used to extract the ... More
Presented by Valentina VERDUCI on 7 May 2012 at 12:00
At high energy and/or for large atomic numbers the wave-function of a generic hadron is dominated by gluon modes and saturates. This is the Color Glass Condensate (CGC) and it can manifest itself in Deep Inelastic Scattering and in Proton-Proton and Heavy Ion Collisions. The evolution of the CGC with energy satisfies a Renormalization Group Equation, the JIMWLK equation. We review the theory and t ... More
Presented by Dionysis TRIANTAFYLLOPOULOS on 11 May 2012 at 09:00
The topic I would like to present is the effect of chiral multiquark interactions (with emphasis on the new eight quark terms) on the temperature versus baryonic chemical potential phase diagram of this extended Nambu Jona Lasinio model of QCD. The talk is mainly based on the works: The Phase diagram for the Nambu-Jona-Lasinio model with 't Hooft and eight-quark interactions. B. Hiller, J. Mor ... More
Presented by Prof. Brigitte HILLER on 11 May 2012 at 11:00
We present a two-flavour linear sigma model with global chiral symmetry and (axial-)vector mesons as well as an additional glueball degree of freedom. We study the structure of the well-established scalar resonances f0(1370) and f0(1500): by a fit to experimentally known decay widths we find that f0(1370) is predominantly a quark-antiquark state and f0(1500) is predominantly a glueba ... More
Presented by Mr. Stanislaus JANOWSKI on 8 May 2012 at 18:30
In this talk we consider the heavy quark limit of nonperturbative Coulomb gauge QCD. In this framework, we demonstrate, under truncation, a direct connection between the Yang-Mills sector of the theory (the temporal component of the gluon propagator) and the quark confining potential. We further show that only color singlet quark-antiquark (meson) and three-quark (baryon) bound states are physical ... More
Presented by Carina POPOVICI on 11 May 2012 at 11:30
Presented by Pol GOSSIAUX on 8 May 2012 at 17:30
I will report on recent results which provides novel qualitative as well as quantitative information on the infrared sector of QCD. In particular i will concentrate on i) the unquenching of the gluon propagator through the SDEs as well as ii) the comparison of these results with new lattice data obtained from configurations containing 2 light and two heavy quarks, iii) the all order equation tha ... More
Presented by Daniele BINOSI on 7 May 2012 at 11:00
We present some highlights of recent results from STAR experiment at RHIC. Selected topics from results on heavy quarkonia production, collectivity and their energy and system dependence are presented from the experiments heavy ion program.
Presented by Sonia KABANA on 10 May 2012 at 09:30
Scalar mesons have been one of the most hotly debated issues of low-energy QCD for decades. Experimental data show the existence of six scalar isosinglet states in the region below 1 GeV -- next to the famous sigma meson, there are five states with the same quantum numbers but higher energies than the energy of the sigma. If we consider u and d quarks as degenerate and work in a theoretical frame ... More
Presented by Mr. Denis PARGANLIJA on 9 May 2012 at 11:30
We utilize Polyakov loop correlations to study 4D compact U(1) flux tubes and the static electron-positron potential in lattice gauge theory. By using field operators it is possible in U(1) lattice gauge theory to probe directly the electric and magnetic fields. In order to improve the signal-to-noise ratio in the confinement phase, we apply the Lüscher-Weiss multilevel algorithm. Our code is w ... More
Presented by Andre AMADO on 10 May 2012 at 11:00
The Parton Distribution Functions (PDFs) and the spin structure of the nucleon are important topics studied by COMPASS in Semi-Inclusive Deep Inelastic Scattering. The Drell-Yan process is a complementary way to access the Transverse Momentum Dependent PDFs (TMD PDFs), using a transversely polarized target. Studying the angular distributions of dimuons from the Drell-Yan reactions in the scatte ... More
Presented by Ms. Márcia QUARESMA on 11 May 2012 at 10:00
Presented by Anja HABERSETZER on 8 May 2012 at 19:00
The PANDA experiment is one of the major projects at the upcoming Facility for Antiproton and Ion Research (FAIR) facility in Darmstadt, Germany. It will study interactions between antiprotons and protons or nuclei in the momentum range of 1.5 GeV/c to 15 GeV/c with a 4pi state-of-the-art detector. The purpose of the experiment is to learn about fundamental aspects of the strong interaction in the ... More
Presented by Tord JOHANSSON on 11 May 2012 at 19:00
We investigate the phase diagram of the so-called Polyakov–Nambu–Jona-Lasinio model at ﬁnite temperature and nonzero chemical potential. The calculations are performed in the framework of the PNJL Lagrangian in the light and strange quark sector (u,d,s) which includes the 't Hooft instanton induced interaction term that breaks the axial symmetry, and the quarks are coupled to the (spatially ... More
Presented by Pedro COSTA on 9 May 2012 at 09:00
In thermodynamics system the correlation length of fluctuations of the order parameter diverges at a critical point. This is the basis of expecting large event-by-event fluctuations for heavy-ion collisions that reach in the critical region. Heavy-ion collisions are however very small and dynamic systems, which at most reach local thermal equilibrium. The effect of critical slowing down is further ... More
Presented by Dr. Marlene NAHRGANG on 11 May 2012 at 17:30
We study the Landau gauge gluon propagator at zero and finite temperature using lattice simulations. Particular attention is given to the finite size effects and to the infrared behaviour. Furthermore, the modeling of the lattice data is discussed.
Presented by Paulo SILVA on 8 May 2012 at 10:00
We examine the phase diagram of hadronic matter when the number of colours Nc, as well as temperature and density, are varied. We show that in this regime a new percolation phase transition is possible, and examine the implications of this transition for extrapolations to physical QCD of the large-Nc limit.
Presented by Stefano LOTTINI on 9 May 2012 at 09:30
We study effective theories for QCD at non-zero temperature and finite chemical potential, using local Polyakov loops as the degrees of freedom. The sign problem is solved by exactly mapping the partition sum to a sum over flux variables with only real and positive weights, and the theory is then accessible to Monte Carlo Techniques. We determine the phase diagram as a function of the temperature ... More
Presented by Ydalia DELGADO MERCADO on 8 May 2012 at 09:00
The thermodynamics of the O(N) model in 1+1 dimensions is studied applying the auxiliary field method. In order to compute the thermodynamical quantities we apply the CJT formalism within the Hartree-Fock approximation extended by sunset diagrams. The numerical results for the renormalized mass of the scalar particles, the pressure, the trace anomaly and the energy density are presented and compar ... More
Presented by Mrs. Elina SEEL on 8 May 2012 at 11:00
Using a microscopic transport model we investigate the evolution of conical structures originating from the supersonic projectile moving through the hot matter of ultrarelativistic particles. Using different scenarios for the interaction between projectile and matter, and different transport properties of the matter, we study the formation and structure of Mach cones. Especially, a dependence of t ... More
Presented by Ioannis BOURAS on 10 May 2012 at 18:30
The knowledge of transport coefficients of the Quark-Gluon Plasma (QGP) gives fundamental insights into the nature of strongly interacting matter under extreme conditions. By means of relativistic heavy-ion collisions, these properties are intended to be experimentally revealed, providing also information about the structure of the produced hot matter. One of the remarkable findings is ... More
Presented by Dr. Marcus BLUHM on 11 May 2012 at 17:00