Partial wave analysis for p̄ p and e+ e− annihilation processes

A new highly modular and generic Partial Wave Analysis (PWA) software package including a general framework for future hadron spectroscopy experiments like PANDA is currently under development. The aims and present status of the software package are summarized and the first PWA results obtained with the already existing tools are presented. These analyses are mainly focused on important aspects of antiproton proton annihilation processes with relevance for the PANDA experiment. For this purpose Crystal Barrel LEAR data are currently under investigation in order to gain a deeper insight to the production mechanisms of vector mesons. In addition analyses for the identification of resonances in radiative J / ψ decays from BESIII data are summarized.     

Total spin-dependent p̄d cross sections at low and intermediate energies

There may be unique (“smoking-gun”) signatures of the breakdown of CPT symmetry, induced in some models of Quantum Gravity entailing decoherence for quantum matter. Such effects can be observed in entangled states of neutral mesons via modifications of the respective Einstein-Podolsky-Rosen (EPR) correlators (“ω-effect”). In the talk I discuss experimental signatures and bounds of the ω-effect in Φ- and B-factories, and argue that the effect might be falsifiable at the next generation facilities.     

Search for narrow states by detection of monochromatic gamma rays in p̄p annihilation at rest

An inclusive γ ray spectrum in p̄p annihilation at rest has been measured with modularized NaI(Tℓ) detectors with statistics several times higher than before. The aim of the experiment was to search for baryonium B in p̄p → γB by detection of narrow lines in the γ ray spectrum. We have not observed any narrow state B with yield greater than 1.5 × 10⁻³ per annihilation and with statistical significance higher than 2σ.     

Search for a fourth generation t' Quark in p ̄p collisions at √s = 1.96 TeV

We present a search for pair production of a fourth generation t' quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb(-1) of proton-antiproton collisions at √s = 1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the t' ?t' production cross section that exclude at the 95% C.L. a t' quark that decays exclusively to W+jet with a mass below 285 GeV. We observe a small excess in the μ+jets channel which reduces the mass range excluded compared to the expected limit of 320 GeV in the absence of a signal.     

Role of current algebra in B→pp̄π(π)

We estimate in a current algebra framework the hadronic matrix elements relevant to the weak B→pp̄π (π) transitions measured recently. The results so obtained are in agreement with the observed values.     

Λ(Λ)production in p(p) collisions

We describe the production of (AA) in p(p) collisions using a constituent quark model which has been successfully applied to the N(N)system.     

A measurement of the inclusive π0 and η production cross sections at high pT in p̄p and pp collisions at s = 24.3 GeV

Inclusive π⁰ and η production at large transverse momentum were studied in both p̄p and pp interactions at √s = 24.3 GeV. The experiment was performed using an internal molecular hydrogen gas jet target in the CERN SPS collider. No significant differences between production in p̄p and pp were observed in the transverse momentum range 2.5 < P_T < 5.1 GeV/c.