Pia Thörngren Engblom

Affiliated Researcher with the KTH Nuclear Physics Group

My physics research focus is on the spin dependence in hadron physics, few-body interactions such as three-nucleon forces, and the studies of fundamental symmetries:

In the JEDI Collaboration our long-term objective is to search for a permanent Electric Dipole Moment (EDM) of light nuclei, such as protons and deuterons, in a storage ring. Observation of such an EDM, or preferably more than one, would be a signature of CP-violation. This in turn is linked to the matter/antimatter asymmetry in our universe, in short why we are here. Presently we do systematic technical investigations in preparation for a precursor experiment. Four of our recent articles were highlighted as Editor's choice and the latest also featured in Physics.

As member of the PAX Collaboration I worked on the development of an effective method for polarizing antiprotons (invited talk LEAP'2013) and measurements of few-nucleon spin observables aiming at testing the predictive power of the modern theory of nuclear forces, the chiral effective field theory (invited talk CGSWHP'2014). A recent paper describes the facility and part of the low-enery spin-physics program at COSY.

Prior to PAX and JEDI I was active in the PINTEX Collaboration at IUCF. We measured double spin observables in the most fundamental nucleon-nucleon inelastic reaction (contribution in PANIC'99 proccedings), and made studies of possible three-nucleon effects in pd breakup (contribution in Few-Body'2004 proceedings). Here is a review of the Indiana Cooler @ IUCF.

As PhD student at Stockholm University, and later as Assistant Professor at Uppsala University, I raised the long standing unsolved puzzle of two-pion production in the scalar isoscalar channel at intermediate energies, the so called ABC effect, named after its discoverers, Abashian, Booth and Crowe (contribution in STORI'96 proceedings). My CELSIUS proposal accepted in 2000 aimed at solving the riddle by means of the first ever exclusive measurements of the two outgoing pions from these light-nuclei collisions using the WASA 4pi-detector. The very last run at CELSIUS measuring the reaction was reported by my PhD student Samson Keleta (sciencedirect or arXiv). The topic has since then generated a large number of articles (see references).

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The 30th PAX Collaboration Meeting took place at KTH/AlbaNova December 8-9 2014, with the following agenda:

Hans StröherShort summary from the COSY coordination meeting

Pia Thörngren & Susanna BertelliStatus of pd breakup analysis at 49 MeV

Dieter  EversheimMagnetic field requests for the TRIC experiment

Mirian TabidzeGEANT simulations for the PAX detector

Christian WeidemannPredictions for longitudinal spin-filtering

Vito CarassitiStatus of the PAX detector support construction

Sergei MerzlyakovStatus of the PAX detector electronic readout

Christian Weidemann         Tests ofPAX (+ANKE) sensors