The H1 and ZEUS collaborations continue to produce final precision
measurements of QCD physics. To achieve high precision
measurements, data from both experiments have been combined leading to
significantly reduced experimental uncertainties. The two collaborations
recently obtained results on combination and QCD analysis of beauty and
charm production cross section measurements in deep...
The negatively charged pions and kaons can be trapped in the Coulomb potential of atomic nucleus forming so called mesonic atoms. It is also conceivable that
a neutral meson could be bound to a nucleus. In this case the binding is exclusively due to the strong interaction and hence such object can be referred to as a mesic nucleus. Here the most promising candidate is the η-mesic nucleus...
The search for multi-quark states beyond the constituent quark model (CQM) has resulted in the discovery of many new exotic states, starting with the X(3872) discovery by Belle in 2003. Also in the sector of charm the CQM does not seem to describe properly all spectrum, despite of the theoretical expectations. These new forms of quark bounds clearly show that mesons and baryons are not the...
Five decades of work on the light scalar-meson nonet composed of $f_0(500)$, $f_0(980)$, $K_0^\star(800)$, and $a_0(980)$, as well as on other scalar mesons, will be briefly reviewed. The different phenomenological descriptions include tetraquark bound states, pure meson-meson models, unitarised effective chiral approaches, unitarised quark models, and lattice-QCD simulations. Also, the...
With about 12/fb collected XYZ data sets, BESIII continues the exploration of the
exotic charmonium-like states. In these talk, recent results of the measurements of
line-shape of e+ e- -> pi0 pi0 psi(3686), K K J/psi, and pi+ D0 D*-, as well as the
J^P determination of Zc(3900) and observation of e+ e- -> phi chi_c1/2 at
sqrt(s)=4.6 GeV will be presented.
We will discuss a calculation of large-Nc masses of light mesons from the QCD sum rules. Two methods based on the use of linear radial Regge trajectories will be presented. We put a special emphasis on the appearance of pole near 0.5 GeV in the scalar isoscalar channel which emerges in both methods and presumably corresponds to the sigma-meson.
In this talk I will briefly review the theory of resonances dynamically generated from hadron-hadron scattering, sometimes referred to as "molecules". I will give some classical examples of meson-meson and meson-baryon systems, as well as a few examples of different approaches to describe the interaction between hadrons. To conclude I will comment on a few recent works that suggest some of the...
QCD-like theories provide testing grounds for truncations of functional equations at non-zero density, since comparisons with lattice results are possible due to the absence of the sign problem. As a first step towards such a comparison, we determine for various theories the chiral and confinement/deconfinement transitions from the quark propagator Dyson-Schwinger equation by calculating the...
With the most recent advances in cosmic-ray physics, from both theoretical and experimental aspects, particles beyond the GZK cut-off (E > 10^20 eV) have been detected by leading collaborations such as Pierre Auger Observatory and Telescope Array. Such observations raise many questions as to how such tremendous energies can be reached and what source can possibly produce them. Although at...
The years 2015 and 2016 marked the start of gravitational wave (GW) astronomy with the discovery of gravitational waves originating from massive black hole mergers. Although searches were performed with a range of dedicated satellites for an electro-magnetic (EM) counter-part no such radiation was detected. As the sensitivity of the GW detectors increased the first detection of a GW produced...
A fully Poincaré-covariant bound state equation derived from a Functional Renormalisation Group equation, the Wetterich equation, via dynamical hadronisation is solved within an effective gluon-decoupled low-energy QCD system, the Quark-Meson model, yielding fully dressed non-perturbative n-point functions for both fermionic and mesonic fields. The problem of analytically continuing the...
Understanding the energy loss of partons traversing the strongly interacting matter created in heavy ion collisions is one of key goals of the heavy ion physics program. After a brief introduction to the field and explaining connections of heavy ion physics and high-energy QCD physics, we present results of phenomenological analyses of various recent jet quenching data. The core of the model...
We use recently formulated framework of perfect fluid hydrodynamics with spin
to study space-time evolution of spin polarization in heavy-ion collisions.
We consider various initial conditions for the hydrodynamic background and
different forms of the spin tensor to study consequences of various physical
assumptions for the time evolution of the system's polarization.
[1] W. Florkowski, B....
Models based on chiral symmetry predict the baryonic states with exotic quantum
numbers (pentaquarks) that have relatively low masses and small widths. We shall
briefly review both theoretical and experimental status of a possibility of exotica in
the light sector. Next we shall show how to extend chiral models to baryons with one
heavy quark and show that one may expect exotic states also...
Starting from the mass matrix in the $\omega_8$, $\omega_0$ space and subsequently by its diagonalization into physical vector meson states $\omega(782)$,$\Phi(1020)$ by means of the orthogonal matrix in the most general form, all eight possible forms of the $\omega$-$\Phi$ mixing are derived. Taking into account the quark structure of the $\omega_8$, $\omega_0$ states and exploiting the ideal...
Algebraic solution of the four independent couples of physically acceptable $\omega$-$\Phi$ mixing forms gives expressions for $\omega_8$ and $\omega_0$ as functions of the unknown mixing angle $\Theta$ and physical states $\omega$, $\Phi$. Substituting for expressions obtained in a such way for $\omega_8$ repeatedly into Gell-Mann-Okubo quadratic mass formula, which yields $m^2_{\omega_8}$ as...
We study decay channel effects in the spectrum of meson states using covariant Bethe-Salpeter equations (BSEs).. The main goal will be to develop BSE kernels that contain explicit decay mechanisms. This will be first explored in the meson sector where, for example, a kernel suitable to study the rho mesons should contain a ρ− > π + π decay mechanism. This will be tackled by including explicit...
We present a phase diagram for SU(3) lattice gauge theory with 695 MeV dynamical
staggered fermions, obtained from effective Polyakov line actions. The derivation is via the method of relative weights and the effective theories are solved at finite chemical potential by mean field theory. We find a phase transition line in the plane of temperature and chemical potential and compare it to...
We study the structure of hybrid static potential flux tubes in SU(2) Lattice Yang-Mills-theory. To this end, we compute the square of the chromoelectric and chromomagnetic field strength components for different hybrid static potential quantum numbers. We find clear indications that the gluonic distribution is different compared to the ordinary static potential and present corresponding first results.
Observed dependence of flow symmetry plane in ultra-relativistic heavy ion collisions on transverse momentum ($p_T$) and pseudorapidity $\eta$ is attributed to lumpy hot-spots raised by the event-by-event fluctuations of the initial states. Studying different orthogonal modes of the same flow harmonic has been suggested as a promising way to explore this phenomena. Prediction of leading and...
Themal shifts and fluctuations at finite temperature below the deconfinement crossover from hadronic matter to the quark-gluon plasma provide a viable way to look for missing states with given quantum number in the hadronic spectrum. We study a realization of the hadron resonance gas (HRG) model in the light quark (uds) flavour sector of QCD to study the fluctuations of baryon number, charge...
I will review the use of hydrodynamics to model heavy-ion collisions at ultrarelativistic energies, and what such modeling has taught us about the properties of QCD matter.
The center vortex model is able to explain confinement, chiral symmetry breaking and the topological charge of QCD vacuum configurations. Maximal center gauge and center projection are very successful methods to detect center vortices. However, they are know to fail for smooth field configurations. We suggest to use the non-Abelian Stokes law to improve the detection of center vortex regions....
The Landau-Khalatnikov-Fradkin transformations (LKFTs) allow to
interpolate $n$-point functions between different gauges. We first
offer an alternative derivation of these LKFTs for the gauge and
fermions field in the Abelian (QED) case when working in the class
of linear covariant gauges. Our derivation is based on the
introduction of a gauge invariant transversal gauge field, which
allows a...
Correlations between two particles separated in pseudorapidity and azimuthal angles, phenomena often called ridge, are sensitive to collective multiparticle effects, and have shown striking similarities in results obtained from proton-proton, proton-lead and lead-lead collisions. This talk presents an overview of ATLAS measurements of azimuthal correlations in proton-proton and proton-lead...
The ATLAS Collaboration has a large program to study various aspects of Quantum Chromodynamics starting from non-perturbative effects over diffractive physics to high precision perturbative calculations. In this talk, we review the latest results on Bose-Einstein correlations measured with the ATLAS detector along with an analysis of the momentum difference between charged hadrons in...
NA61/SHINE is a fixed target experiment at the CERN Super-Proton-Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and to study the properties of the onset of deconfinement. In order to reach these goals, a study of hadron production properties is performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a...
In ultrarelativistic heavy-ion collisions at RHIC, a new state of nuclear matter -- strongly interacting Quark Gluon Plasma is created under extreme condotions. Owing to their large masses, heavy quarks are predominantly produced at early stages of collisions hence prove an exceptional probe for exploring properties of the hot and dense medium.
The Heavy Flavor Tracker and Muon Telescope...
The AMADEUS collaboration is performing experimental investigations in the sector of the low energy strangeness hadron physics.
The strategy consists of taking advantage of the monochromatic low-momentum negatively charged kaons produced by the DA$\Phi$NE collider,
investigating the K$^-$ nuclear absorption proceses in the materials of the KLOE detector, used as an active target.
The K$^-$...
The NA48/2 experiment at CERN collected a very large sample of charged kaon decays into multiple final states. This data allow measurements related to QCD. We obtained our final measurement of the charged kaon semileptonic decays form factors based on 4.28 million Ke3 and 2.91 million Kmu3 selected decays, with the smallest uncertainty for Ke3 and a competitive result for Kmu3 and leading to...
The PANDA experiment, a core project of the future Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, will investigate antiproton proton annihilations with the aim to explore fundamental questions in the nonperturbative regime of QCD. The multi-purpose detector is currently under construction and ensures in combination with an intense and high quality anti-proton beam in the...
