Extracting Hypernuclear Properties from the (e, e′K+) Cross Section

Experimental studies of hypernuclear dynamics, besides being essential for the understanding of strong interactions in the strange sector, have important astrophysical implications. The observation of neutron stars with masses exceeding two solar masses poses a serious challenge to the models of hyperon dynamics in dense nuclear matter, many of which predict a maximum mass incompatible with the data. In this paper, it is argued that valuable new insight can be gained from the forthcoming extension of the experimental studies of kaon electro production from nuclei to include the 208Pb(e,e′K+)Λ208Tl process. A comprehensive framework for the description of kaon electro production, based on factorization of the nuclear cross section and the formalism of the nuclear many-body theory, is outlined. This approach highlights the connection between the kaon production and proton knockout reactions, which will allow us to exploit the available 208Pb(e,e′p)207Tl data to achieve a largely model-independent analysis of the measured cross section.

The Collins asymmetry in electroproduction of Kaon at the electron ion colliders within TMD factorization

We apply the transverse momentum dependent factorization formalism to investigate the transverse single spin dependent Collins asymmetry with a $$\sin (\phi _h+\phi _s)$$sin(ϕh+ϕs) modulation in the semi-inclusive production of Kaon meson in deep inelastic scattering process. The asymmetry is contributed by the convolutions of the transversity distribution function $$h_1(x)$$h1(x) of the target proton and the Collins function of the Kaon in the final state. We adopt the available parametrization of $$h_1(x)$$h1(x) as well as the recent extracted result for the Kaon Collins function. To perform the transverse momentum dependent evolution, the parametrization of the nonperturbative Sudakov form factor of the proton and final state Kaon are utilized. We numerically predict the Collins asymmetry for charged Kaon production at the electron ion colliders within the accuracy of next-to-leading-logarithmic order. It is found that the asymmetry is sizable and could be measured. We emphasize the importance of planned electron ion colliders in the aspect of constraining sea quark distribution functions as well as accessing the information of the nucleon spin structure and the hadronization mechanism.

Theory of Time Asymmetry and Strangeness Oscillation of K°

The predicted value for the T-asymmetry, AT eory, of the neutral kaons strangeness oscillation in the framework of the chronotopological stochastic quantum field theory is AT eory = 6 . 6 x l 0 - 3 and the corresponding diameter of the interaction proper-time neighborhood, is δ(τχ) = 2.382 χ IO- 2 7 s. The antiproton energy in the reaction for the kaon production is Ep = 200 MeV. The time evolution operator, C(T\K), acting on the state vector gives two contributions, one unitary and one decoherent. AT eory as a function of Ep shows that Κ - decays (antimatter) were more abundant than matter decays at higher temperatures of the universe. C(T\K) appears in two disjoint subsets of denumerably many forms, unitary and non-measure preserving. The evolution operator of the standard quantum field theory is identical to the zerothorder element of the unitary subset. The set of evolution paths Schronotop., produced by C(7A„) is denumerable (quantized) in contradistiction to the set, SFeynman, of trajectories in the path integral which is continuous. The value measured recently by the CPLEAR-Collaboration at CERN is {A§xper·) = (6.6 ± 1.3) x 10"3 . The agreement with the predicted value is excellent.

In-Medium Strangeness Production and Hyperon-Potentials

A hot topic of current research concerns the Equation of State (EoS) of nucleons and, in particular, of hyperons in dense nucleonic media. The study of the EoS at nucleon densities far beyond saturation has been initiated several decades ago, however, the behavior of the EoS for strangeness particles is still an open issue. The strangeness part of the EoS is very important not only for the physics of exotic (hyper)nuclei, but also crucial for nuclear astrophysics, e.g., neutron star physics.Here we present our recent investigations related to the theoretical treatment of in-medium hyperon-interactions as well as first preliminary experimental results from pion-induced reactions. The theoretical study is based on the well-established Non-Linear Derivative (NLD) model, which is extended to the strangeness sector via SU(6) symmetry arguments. It turns out that the NLD-predictions are consistent with microscopic models based on the chiral-EFT theory. On the other hand, recent experimental HADES-data on hyperon and kaon production from pion-induced reactions indicate sensitivities on the underlying in-medium hyperon potentials. We thus conclude that, the recent experimental data from pion-induced reactions will definitely set stringent constraints on the still less understood hyperon-potentials in nucleonic matter.