Workshop for young scientists with research interests focused on physics at FAIR

We review recent developments on the analysis of the Nucleon-Nucleon interaction with the corresponding propagation of statistical uncertainties originating from NN scattering experimental data. We also ponder on the consequences of this uncertainties on the predictive power of low energy chiral interactions and the required target numerical accuracy of nuclear structure calculations of light nuclei.

In this talk, the recent experimental and theoretical advances in the knowledge of the spectrum and structure of XYZ states will be reviewed, with special emphasis on the case of the $Z_c(3885)/Z_c(3900)$

The structure of heavy mesons located above the thresholds for the open flavour production as been largely discussed in the recent years. The observation of charged exotic states highlighted the importance of the light quark degrees of freedom in the description of both quarkonia and bottomonia. We will report the most recent experimental measurements performed by the Belle collaboration...

The BESIII Experiment at the Beijing Electron Positron Collider (BEPC2) collected large data samples for electron-positron collisions with center-of-mass above 4 GeV during 2013 and 2014. The analysis of these samples has resulted in a number of surprising discoveries, such as the discoveries of the electrically charged "Zc" structures, which, if resonant, cannot be accomodated in...

Quantum Chromodynamics (QCD), the theory of strong interactions, predicts several types of bound states. Among them are mesons (quark-antiquark) and baryons (quark-quark-quark), which have been the only states observed in experiments for years. However, in the last decade many states that do not fit this picture have been identified. There is growing evidence that at least some of the new...

There are several mesons whose $q\bar q$ quark-structure is doubted or even excluded. Therefore it is interesting to look for alternative structures for those candidates. Four-quark systems are a possible explanation. One way to approach four-quark models quantitatively is by means of lattice QCD. We study the heavy-light four-quark system $b\bar b l \bar l$ ($B\bar B$) on the lattice. The...

The Compressed Baryonic Matter (CBM) experiment at the future FAIR (Facility for Antiproton and Ion Research) complex will investigate the phase diagram of strongly interacting matter at high baryon density and moderate temperatures in A+A collisions from 4-35 AGeV. One of the key detector components required for this CBM physics program is the RICH (Ring Imaging CHerenkov) detector, which is...

HADES provides a large acceptance combined with a high mass-resolution and therefore allows to study dielectron and hadron production in heavy-ion collisions with unprecedented precision. With the high statistics of seven billion Au-Au collisions at 1.23 AGeV recorded in 2012 the investigation of high-order flow harmonics is possible. Collective flow phenomena are a sensitive probe for the...

The future PANDA experiment at FAIR has a rich and broad physics program. Hyperon production and the study of their properties is one of them. Antihyperon-hyperon pairs can be produced in antiproton-proton collisions through the annihilation of at least one light (u, d) antiquark-quark pair and the creation of sbar s antiquark-quark pairs. Ground state hyperons can only decay through the weak...

We discuss some properties of QCD at nonzero density and nonzero temperature. At nonzero density we describe the emergence of inhomogeneous quark-antiquark condensate in the framework of QCD effective models. We show that such an inhomogenous condensate is favored at high enough density. In particular, we use an effective hadronic model which makes use of chiral symmetry and includes a light...

Simulations of dense quark matter are hampered by the sign problem, invalidating the usual importance sampling based methods of lattice QCD, and preventing the determination of the location of the critical point on the QCD phase diagram. Possible workarounds and solutions to the problem are discussed, with emphasis on the review of the recent successes of the Complex Langevin approach, based...

The advent of new accelerators technologies, like the use of intense and stored antiprotons beams, will set an inflection point in what we know today as Modern Physics. In particular, the PANDA experiment at the FAIR facility in Darmstadt, (Germany), will help to elucidate many of the still obscure aspects of the strong interaction, and consequently build a link between nuclear and hadron...

Pseudoscalar mesons (P) decaying into lepton-antilepton pairs can provide a signal to physics beyond the Standard Model. Within the Standard Model P->l+l- proceeds via a two-photon intermediate state. Therefore it is a fourth order electromagnetic process, and thus suppressed. Determinations of upper limits has previously been performed for pi0, eta and eta' decaying to lepton-antilepton...

Charmonium spectroscopy is an ideal tool to systematically study the strong interaction between the fundamental building blocks of matter, quarks and gluons. From a theoretical and experimental point of view, charmonium is considered as one of the most controllable two-quark systems. Hence, precision measurements of the properties of charmonia allow a thorough study of the non-perturbative...

The Compressed Baryonic Matter project (CBM) at the upcoming SIS100 heavy-ion accelerator at the FAIR (Darmstadt, Germany) will explore the QCD phase diagram in so far unknown regions of moderate temperatures and high baryonic densities for the hadronic freeze-out. Thus, the experiment is expected to gain progress in the understanding of the phase transition between hadronic matter and a...

We study the broad light scalar kaonic resonance k0*(800) as a dynamically generated state. Namely, we show that this resonance emerges when investigating the heavier quark-antiquark scalar state k0*(1430) dressed by quantum fluctuations with one kaon and one pion circulating in the loops. We analyse the spectral function in the whole kaonic sector up to 1.8 GeV and determine the position of...

The electromagnetic calorimeter (EMC) of the PANDA detector at the future FAIR facility will be used to study proton - antiproton interaction. The EMC of the target spectrometer with its expected excellent performance and efficiency for electromagnetic probes over a wide energy range from 10 MeV up to 15 GeV, will be one of the central components to achieve the physical goals. The barrel part...

We study the production of (anti-) strange and multi-strange hadrons in heavy ion collisions from FAIR/NICA to RHIC energies within the Parton-Hadron-String Dynamics (PHSD) microscopic transport approach, which contains the partonic and hadronic dynamics. We observed traces from the QGP by looking at a verity of ‘bulk’ observables like the excitation functions of particle yields, pt- and...

The scientific mission of the Compressed Baryonic Matter (CBM) experiment is the study of the nuclear matter properties at the high baryonic densities in heavy ion collisions at the Facility of Antiproton and Ion Research (FAIR) in Darmstadt. The 5.15 MJ superconducting dipole magnet will be used in the silicon tracking system of the CBM detector. It provides a magnetic field integral of 1 Tm...

In the framework of the extended Linear Sigma Model we study four baryonic multiplets introduced via the mirror assignment, which allows chirally invariant mass terms. We first investigate formal features of a three-flavor treatment of the problem and then study the reduction to the two flavor case. In the latter, four baryonic doublets are present: the nucleon $N(939)$ and the Roper $N(1440)$...

Nuclear astrophysics is the study of the origin of the elements, nuclear energy generation in space, and the nature of ultradense matter. Experimental nuclear astrophysics studies require access to nuclides across nearly the whole nuclear chart, from the proton dripline to the neutron dripline. In order to reach these extremes, cutting-edge rare isotope facilities such as FAIR are required. I...

Using data samples collected with BESIII detector at BEPCII collider, we measure Born cross section of e+e- pp ̅ at center-of-mass energies √s from 2232.4 to 3671.0 MeV. The effective electromagnetic form factor of the proton is deduced with assumption that electric and magnetic form factors are equal(GE=GM). The ratio |GE/GM|and |GM |are extracted by fitting polar angle distribution of...

Exclusive binary annihilation reactions induced by antiprotons of momentum from 1.5 to 15 GeV/c can be extensively investigated at FAIR/PANDA [1]. The hadronization process (how a hadron is built from the quantum vacuum created by the pp annihilation and how does it mass, and quantum numbers arise) is the most fundamental problem in QCD. We are specially interested in the channel of charged...

The RHIC Beam Energy Scan (BES-I) program, which covers center-of-mass energies 7.7 GeV – 62.4 GeV, was proposed to look for the turn-off of signatures of the quark gluon plasma (QGP), search for a possible QCD critical point, and study the nature of the phase transition between hadronic and partonic matter. RHIC BES-I has shown that the partonic interactions are dominant at center-of-mass...

Particle flow and reaction plane reconstruction performance using the Projectile Spectator Detector (PSD) in the CBM experiment at the future FAIR facility will be presented. The PSD is a compensating lead-scintillator calorimeter designed to measure the energy distribution of the forward going projectile nucleons and nuclei fragments (spectators) produced close to the beam rapidity. The main...

We model early times dynamics of relativistic heavy ion collisions by an initial color electric field which decays to a plasma by the Schwinger mechanism. The dynamical evolution of the color field is coupled to the dynamics of the many particles system produced by the decay, which is described by relativistic kinetic theory at fixed viscosity to entropy density ratio η/s. The backreaction of...

We present the calculations on the relations between Wilson coefficients in non-relativistic QCD and potential non-relativistic QCD by using non-linear field transformations to implement Poincar\'e invariance in them. The results confirm the known relations and it can further be used to derive the constraints between the coefficients of the higher order terms in the expansions. Similarly, its...

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/psi and psi’ resonances. In particular decays of these two resonances provide a rich and clean environment to study hadrons consisting out of light quarks and search...

We use nonrelativistic effective field theories to obtain from QCD the Schrödinger equations describing quarkonium hybrids and the static interaction potential in the region from small to intermediate quark-antiquark distance. The nonperturbative parameters appearing in the potential are fixed by the lattice calculation of the gluelump mass and the hybrid static energy, the rest is calculated...

Understanding the excitation pattern of baryons is indispensable for a deep insight into the mechanism of non-perturbative QCD. Up to now only the nucleon excitation spectrum has been subject to systematic experimental studies while very little is known on excited states of double or triple strange baryons. In studies of antiproton-proton collisions the PANDA experiment is well-suited for a...

In the summer of 2014, HADES conducted measurements with secondary pion-beam using different targets. The program is devoted to measure dielepton radiation from baryonic resonances. In particular we investigated a sub-threshold coupling of rho to baryonic resonances in the second resonance region (N(1520), N(1535)). Most of the beam time was dedicated to measurement of e+e- production from...

The Beam Energy Scan (BES) program was carried out at RHIC with the main goals to find signatures for the disappearance of the QGP, a QCD phase transition, and for a critical point. An overview of various observables studied by STAR and PHENIX to identify those structures in the QCD phase diagram will be presented. Furthermore, I will give an outlook on the BES phase II program which is...

Virtual photon decays to lepton pairs are considered as an ideal probe to access information of all stages of heavy-ion collisions. However, this probe is very rare and is surrounded by a high track density environment produced in heavy-ion collisions. This complicates the track reconstruction and makes identification of lepton pairs challenging. Events of Au+Au collisions at a beam energy of...

In this talk I would like to give a brief review on our recent studies regarding the structure of nuclei around 100Sn. I will first introduce the collectivity properties in Sn and Te isotopes and the possible role played by the cross-shell excitation and the quadrupole-quadrupole correlation. In particular, I will also show that the seniority symmetry is dynamically conserved in j=9/2 shells...

The Super FRagment Separator (Super-FRS) at the FAIR facility will be the largest in-flight separator of heavy ions in the world. The separation principle is based on the use of beam collimators to stop the unwanted ions. In one of the most common situations, the heavy ions are produced by a fission reaction of a primary Uranium-238 beam (1.5 GeV/u) hitting a Carbon-12 target. In this...

The Dyson-Schwinger-Bethe-Salpeter-equation approach provides a covariant framework to study mesons, and more generally hadrons, in QCD. I'll discuss both the role of truncations in numerical studies based on this approach, as well as recent results [1-4] for spectroscopy and properties of heavy and light quarkonia with both conventional and exotic-vector quantum numbers. [1]...

The HADES experiment at GSI Helmholtzzentrum f\"{u}r Schwerionenforschung in Darmstadt (Germany) is fix target experiment using SIS-18 accelerator to study collisions of protons, heavy-ions or secondary pions with target nuclei. HADES is designed to study reactions with di-electrons in final state but it provides also very accurate measurement of charged hadrons. The pion induced reactions...

In this talk we present the SMASH model, a next-generation hadronic transport implementation that is designed to describe the non-equilibrium evolution of hadronic matter in heavy-ion collisions. After laying out the basic principles and ingredients of the model, we discuss a few benchmark results that illustrate the correct behaviour of the code. We then present first dilepton spectra...

One of the physics highlights of the future PANDA experiment is to search for exotic states that have been predicted by theory, and whose properties are governed by the presence of valence gluons. Such exotic states can be formed directly and copiously in proton-antiproton annihilations. The challenge lies in reducing the enormous background yield while preserving a high efficiency for the...

The BESIII experiment is a multi-purpose detector operating on the electron-positron collider BEPCII in Beijing. Since 2008, the world's largest sample of J/psi, psi' were collected. Due to increasing luminosity, the inner drift chamber is showing signs of ageing. In 2014, an upgrade was proposed by the Italian collaboration based on the Cylindrical Gas Electron Multiplier (CGEM) technology,...

The CBM experiment at FAIR will investigate the properties of nuclear matter at extreme conditions created in ultrarelativistic heavy-ion collisions. Its core detector — the Silicon Tracking System (STS) — will allow to reconstruct charged particle tracks with high precision and determine their momentum. The detection of rare probes requires the STS to be capable to measure at interaction...

Baryon number density perturbations offer a possible route to experimentally measure baryon number susceptibilities and heat conductivity of the quark gluon plasma. We study the fluid dynamical evolution of local and event-by-event fluctuations of baryon number density, flow velocity and energy density on top of a (generalised) Bjorken expansion. To that end we use a background-fluctuation...