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A comprehensive approach to the physics of mesons
No full textWe develop an inclusive approach for the self-consistent solution of coupled sets of Bethe-Salpeter and Schwinger–Dyson equations in QCD. This framework allows us to maintain the axial Ward-Takahashi identities of the theory within advanced approximation schemes, such as the skeleton or three-particle irreducible expansions. For this purpose we reformulate the Schwinger-Dyson equation of the axial-vector vertex such that the bulk of its quantum corrections is expressed in terms of an effective vertex, containing an additional gluon. Crucially, this vertex satisfies a symmetry-induced relation of its own, which involves the full quark-gluon vertex. As a result, the Schwinger-Dyson equation reproduces the standard Ward-Takahashi identity satisfied by the axial-vector vertex. Consequently, the known relation between the quark mass function and the wave function of the pion in the chiral limit is duly fulfilled. The present approach offers valuable insights into the interplay between symmetry and dynamics, and provides a practical path towards computations of hadron physics within sophisticated approximations. In particular, the one-loop dressed truncation of the key dynamical equations, including that of the quark-gluon vertex, is shown to be completely compatible with the required symmetry relations. Further extensions and potential phenomenological applications of the developed framework are briefly discussed
Exploring the DGLAP resummation in the JIMWLK Hamiltonian
No full textWe explore the recently derived equation that resums DGLAP corrections to the JIMWLK Hamiltonian in the simplified setting of the SU(2) gauge theory. We solve the equation numerically for the scattering matrix of a dressed gluon for a particular initial condition, that corresponds to a dipole initial state. We evolve the S-matrix of a single dressed gluon from the scale QP, which is the inverse color correlation length in the projectile to Q ≫ Q_P which corresponds to the hard resolution scale provided by the target. As expected, S ceases to be unitary if evolved to significant ln Q^2/Q_P^2. Our numerical results indicate an interesting universal (independent of the coupling constant) pattern for this deviation from unitarity
Effects of beam plane correlation on injection efficiency
No full textThe effectiveness and efficiency of a beam injection scheme is crucial to achieve high beam intensities while minimizing possible beam losses. The classical method for injecting from a linac to a synchrotron is the multi-turn injection. In this scheme the quality of the injected beam as well as of the injection scheme depends on factors as beam emittance, type of local bump ramp, chromaticity, dispersion and beam intensity. This approach relies on the decorrelation between the planes of the injected beams. However, investigations on the beam coming from the linac have suggested the possibility that a beam correlation may exist*. We present here an investigation of the effect of a correlated beam on the efficiency of the multi-turn injection for several degrees of correlation
Clusters as a probe of the equation-of-state of strongly interacting matter
No full textWe investigate the influence of the equation-of-state (EoS) of strongly interacting matter created in heavy-ion collisions on the light cluster and hypernuclei production within the Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) microscopic transport approach. In earlier PHQMD calculations, nucleon interactions were modeled using a static, density-dependent potential corresponding to the soft and hard equation-of-state. In this study, we incorporate a momentum-dependent potential for the baryon-baryon interaction, derived from the soft EoS. We study the influence of momentum dependent potential on light cluster production.}
Renormalization-group consistent treatment of color superconductivity in the NJL model
No full textThe Nambu–Jona-Lasinio (NJL) model and specifically its extension to color superconductivity (CSC) is a popular effective model for investigating dense quark matter. However, the reliability of its results is challenged by cutoff artifacts, which emerge if temperature or chemical potential are of the order of the cutoff energy scales. In this work, we generalize an idea from Braun et al. [SciPost Phys. 6, 056 (2019)], which is based on the requirement of renormalization-group (RG) consistency and has successfully been applied to the two-flavor quark-meson-diquark model, to the NJL model for electrically and color-neutral three-flavor color-superconducting quark matter. To this end, we analyze the medium divergences of the model and eliminate them by appropriate counterterms, introducing three different schemes. We show that the RG consistent treatment removes the cutoff artifacts of the conventional regularization and enables the investigation of CSC matter at higher densities by the model. Our studies reveal the emergence of a so-called d-quark superconducting (dSC) phase within the melting pattern of the color-flavor locked phase at high chemical potentials, consistent with earlier Ginzburg-Landau analyses
Pilot study: Experimental nuclear physics - dataset metadata generator
No full textThis is a Django & React web application for the GSI Metadata Platform. It allows the generation of dataset metadata for fundamental physics - experimental nuclear physics at GSI Helmholtzzentrum für Schwerionenforschung GmbH. This acts a pilot study for the OSCARS Funded NAPMIX project. --
Diagnostics of Spin-Polarized Ions at Storage Rings
No full textPolarized heavy ions in storage rings are seen as a valuable tool for a wide range of research, from the study of spin effects in relativistic atomic collisions to the tests of the Standard Model. For forthcoming experiments, several important challenges need to be addressed to work efficiently with such ions. Apart from the production and preservation of ion polarization in storage rings, its measurement is an extremely important issue. In this contribution, we employ the radiative recombination (RR) of polarized electrons into the ground state of initially hydrogen-like, finally helium-like, ions as a probe process for beam diagnostics. Our theoretical study clearly demonstrates that the RR cross section, integrated over photon emission angles, is highly sensitive to both the degree and the direction of ion polarization. Since the (integrated) cross-section measurements are well established, the proposed method offers promising prospects for ion spin tomography at storage rings.Keywords: spin-polarized ions; radiative recombination; integrated recombination cross sectio
