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Numerical and pseudo data for pion electroproduction from four reaction channels, p ( γ*, π 0 ) p , p ( γ*, π + ) n , n ( γ*, π − ) p , and n ( γ*, π 0 ) n , from threshold up to W = 1.575 GeV are used to perform a single energy partial wave analysis. As a constraint, higher partial waves are taken from the MAID07 model and lower partial waves are fitted. It is demonstrated that truncated partial wave analysis in a full isospin can be obtained with this procedure. The results for photon virtuality Q 2 = 0.5 GeV 2 are presented. Electromagnetic E ℓ± , M ℓ± , and longitudinal L ℓ± multipoles are presented and discussed. In the first step, numerical data are generated, and the optimal number of lower partial waves required for a good data fit is determined. In the second step, the same procedure is applied using generated pseudo data.

In March 2019 the HADES experiment recorded 14 billion Ag+Ag collisions at √SNN = 2.55 GeV as a part of the FAIR phase-0 physics program. With the capabilities to measure and analyze particles forming the bulk matter, namely pions, protons and light nuclei, as well as rare probes like dilepton decays of vectormesons and strange hadrons, the HADES experiment allows to study the properties of matter at high densities in great detail. In this contribution a special focus is put on the reconstruction of weakly decaying strange hadrons.

We investigate two-body non-leptonic D→SS weak decays, where S denotes a light scalar meson such as a0/a0(980), f0/f0(980), or σ0/f0(500). Short-distance topologies from W-boson emission and annihilation (exchange) are found to be negligible, while long-distance final-state interactions provide the dominant contributions. In particular, triangle rescattering processes, D→πη(′)→σ0a0 and D→a1(1260)η→σ0a0, mediated by pion exchange in πη(′) and a1(1260)η scatterings, respectively, are identified as the leading mechanisms. Our calculations yield branching fractions B(Ds+→σ0a0+)=(1.0±0.2-0.2+0.1)×10-2, B(D+→σ0a0+)=(1.1±0.2-0.2+0.1)×10-3, and B(D0→σ0a00)=(0.9±0.2-0.3+0.2)×10-5. For the Cabibbo-allowed decay mode Ds+→f0a0+, the near-threshold condition mDs≃mf0+ma0 limits the phase space, suppressing the branching fraction to (3.4±0.3-0.9+0.4)×10-4. These results highlight rescattering-induced D→SS decays as promising channels for experimental studies at BESIII, Belle(-II), and LHCb.

PHENIX observed a 20% suppression in the production of high pT neutral pions in the most central (0-5%) d+Au collisions at 200 GeV. Through the simultaneous measurement of high pT direct photons (γdir) and π0 production for event samples selected by event activity, the final state effects could be disentangled from cold-nuclear-matter effects and event-selection biases that are inherent in using the standard Glauber model. This isolation of final state effects is achieved by approximating the nuclear modification factor by the double ratio RxA = (γdir/π0)pp/(γdir/π0)xA. While the cold-nuclear-matter effects in x+A collisions cancel in the (γdir/π0) ratio, the effective number of binary collisions is given by NCollEXP = γxAudir / γppdir, which eliminates the dependence on the Glauber model. In addition, many systematic uncertainties cancel in the double ratio.

A theoretical model of two-pion photoproduction is presented. The model encodes the prominent ρ(770) resonance and the expected leading background contribution coming from the Deck mechanism. To validate the model, angular moments are computed and compared with the CLAS dataset. After fitting a number of free parameters, the model provides a good description of the data.

Hyperons are a unique probe to study the non-perturbative aspects of the strong interaction. At HADES, they are produced in proton or pion induced reactions at kinetic energies up to 4.5 GeV. Already in the past, HADES has shown its potential for hyperon physics, including λ polarization, λ -N interaction and measurements of the λ (1405) and λ (1520) line-shapes. The HADES detector has recently been extended with a forward detector, partly developed for the PANDA experiment, extending the acceptance for hyperon channels at forward angles. The PANDA@HADES initiative gives the opportunity for an even richer hyperon program. The current main objectives are the production of hyperon resonances, electromagnetic decays of hyperons with special focus on hyperon Dalitz decays and double strangeness production, including a λ – λ interaction study and ξ − production. First results from the ongoing studies promise a successful execution of the program. In the future, there is the possibility for a pion beam experiment with HADES, enabling further hyperon studies.

The HADES collaboration has recently studied the π − + C reaction at 0.685 GeV/c, using the GSI pion beam. This provides a first insight in the pion-nucleus dynamics in the energy range above the Δ(1232) resonance, which has been very poorly studied and is relevant for the study of heavy-ion collisions in the few GeV range. Measurements of π ± , p, d and t were provided in various exit channels (inclusive, p π − , p π + , pp, π + π − , pπ − π + …,) and compared to predictions of the INCL++ cascade and of transport models (SMASH, RQMD.RMF, GIBUU). The results allow to test selectively the capacity ofsuch models to describe the various mechanisms (quasi-elastic, multipion production, rescatterings and pion absoprtion). The sensitivity of the data measured in the quasi-elastic channel to short range correlations is also investigated.

We review lattice results related to pion, kaon, D-meson, B-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor f+(0) arising in the semileptonic K→π transition at zero momentum transfer, as well as the decay constant ratio fK/fπ and its consequences for the CKM matrix elements Vus and Vud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)L×SU(2)R and SU(3)L×SU(3)R Chiral Perturbation Theory. We review the determination of the BK parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for mc and mb as well as those for D- and B-meson decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant αs. Finally, in this review we have added a new section reviewing results for nucleon matrix elements of the axial, scalar and tensor bilinears, both isovector and flavor diagonal.

In these proceedings, we present the measurements of charged K+ − K+ and neutral KS0, - KS0 correlation functions from Au+Au fixed-target collisions at √sNN = 3.0, 3.2, 3.5, 3.9 and 4.5 GeV at STAR. This is the first such systematic measurement of correlation functions involving strangeness in the high baryon density region. The source size values do not exhibit a clear energy dependence, and the transverse mass dependence of source size for kaons does not align with the trend observed for pions. Parameters extracted from UrQMD transport model calculations qualitatively capture the measured values.

The applicability of the effective models to the description of baryons and the behaviour of ratios of strange baryons to pions is discussed. In the framework of the EPNJL model, the Bethe–Salpeter equation is used to find masses of baryons, which are considered to be in a diquark-quark state. Baryon melting is discussed at a finite chemical potential, and a flavor dependence of the hadronic deconfinement temperature is pointed out. It is shown that the description of the diquark-quark state at finite chemical potential is limited due to the occurrence of Bose condensate. This effect is strongly manifested in the description of light diquarks and baryons. Both the Λ[sup.0] /π[sup.+] and Ξ[sup.−] /π[sup.+] ratios show a sharp behaviour as functions of the T/μ[sub.B] variable, where T and μ[sub.B] are calculated along the melting lines.