Anselm G. Vossen
Assistant Professor of Physics
In Quantum Chromodynamics (QCD), the theory of the strong interactions, the nucleon emerges as a strongly interacting, relativistic bound state of almost massless quarks and gluons.
Fifty years of experimental investigations into the nucleon's internal structure have provided remarkable insight into quark and gluon dynamics. However, many outstanding questions remain.
For example, the origin of the spin of the proton is still eludes us and many other properties of the nucleon cannot yet be derived from first order calculations. Even fundamental aspects like a quantitative understanding of the origin of the mass of the nuclei (and thus most of the visible mass in the universe) as well as the confinement of quarks into hadrons remain outside our current understanding.
My research approaches these questions from two sides. At the newly upgraded Jefferson Lab facility, we use electron proton scattering data to map out the 3D dynamics of the nucleon. We are in particular interested in polarized probes that are sensitive to spin-orbit coupling in the proton wavefunction.
And at the newly constructed Belle II experiment, we use electron-positron annihilation data, to study how hadrons emergy from initial quarks. We are in particular interested how the quantum numbers of the inital quark, like spin, are expressed in the final state hadrons.
My group also works on precision tests of the flavor sector of the standard model at the intensity frontier. To this end we study the properties of B meson detected with the Belle II experiment.
Vanhoefer, P., et al. “Study of B0 → ρ+ ρ- Decays and implications for the CKM angle φ 2.” Physical Review D, vol. 93, no. 3, Feb. 2016. Scopus, doi:10.1103/PhysRevD.93.032010. Full Text
Glattauer, R., et al. “Measurement of the decay B →dℓνℓ in fully reconstructed events and determination of the Cabibbo-Kobayashi-Maskawa matrix element.” Physical Review D, vol. 93, no. 3, Feb. 2016. Scopus, doi:10.1103/PhysRevD.93.032006. Full Text
Adamczyk, L., et al. “Probing parton dynamics of QCD matter with Ω and φ production.” Physical Review C, vol. 93, no. 2, Feb. 2016. Scopus, doi:10.1103/PhysRevC.93.021903. Full Text
Adare, A., et al. “Scaling properties of fractional momentum loss of high- pT hadrons in nucleus-nucleus collisions at sNN from 62.4 GeV to 2.76 TeV.” Physical Review C, vol. 93, no. 2, Feb. 2016. Scopus, doi:10.1103/PhysRevC.93.024911. Full Text
Hamer, P., et al. “Search for B0 →π-τ+ντ with hadronic tagging at Belle.” Physical Review D, vol. 93, no. 3, Feb. 2016. Scopus, doi:10.1103/PhysRevD.93.032007. Full Text
Masuda, M., et al. “Study of π0 pair production in single-tag two-photon collisions.” Physical Review D, vol. 93, no. 3, Feb. 2016. Scopus, doi:10.1103/PhysRevD.93.032003. Full Text
Adamczyk, L., et al. “Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and ϕ Meson in Au+Au Collisions at √[sNN]=200 GeV.” Physical Review Letters, vol. 116, no. 6, Feb. 2016, p. 062301. Epmc, doi:10.1103/physrevlett.116.062301. Full Text
Adare, A., et al. “φ Meson production in the forward/backward rapidity region in Cu + Au collisions at s NN =200 GeV.” Physical Review C, vol. 93, no. 2, Feb. 2016. Scopus, doi:10.1103/PhysRevC.93.024904. Full Text
Adare, A., et al. “Transverse energy production and charged-particle multiplicity at midrapidity in various systems from sNN =7.7 to 200 GeV.” Physical Review C, vol. 93, no. 2, Feb. 2016. Scopus, doi:10.1103/PhysRevC.93.024901. Full Text
Adare, A., et al. “Measurement of higher cumulants of net-charge multiplicity distributions in Au + Au collisions at sNN =7.7-200 GeV.” Physical Review C, vol. 93, no. 1, Jan. 2016. Scopus, doi:10.1103/PhysRevC.93.011901. Full Text