2022 Frontiers and Careers in Nuclear and Hadronic Physics

Session

Proton radius puzzle

Aug 5, 2022, 4:20 PM

26-414 (MIT Laboratory for Nuclear Science)

Conveners

Proton radius puzzle

• Jackson Pybus (MIT)

14. Deuteron Charge Radius Experiment (DRad) at Jefferson Lab

Jingyi Zhou (Duke University)

8/5/22, 4:20 PM

High precision muonic deuterium spectroscopic measurements found a significantly smaller (7$\sigma$) deuteron charge radius compared to the CODATA recommended value, creating the ``deuteron charge radius puzzle''. In order to investigate this, the DRad experiment (Jefferson Lab PR12-20-006) was proposed to measure the $e-d$ elastic scattering cross section in a very low momentum transfer...

28. Two photon exchange at Jefferson Lab

Tyler Kutz (MIT/GW)

8/5/22, 4:40 PM

Two photon exchange (TPE) and the larger class of hadronic box diagrams can be a significant radiative correction to lepton scattering and beta decay measurements. Notably, it has been hypothesized that TPE could be responsible for the proton form factor ratio discrepancy. However, these diagrams remain difficult to calculate without large uncertainty and model-dependence, and theoretical...

25. Soft-photon radiative corrections to the e^− p→e^−p l^− l^+ process

Niklas Keil (JGU Mainz)

8/5/22, 5:00 PM

We calculate the leading-order QED radiative corrections to the process e^− p→e^− p l^− l^+ in the soft-photon approximation, in two different energy regimes which are of relevance to extract nucleon structure information. In the low-energy region, this process is studied to better constrain the hadronic corrections to precision muonic hydrogen spectroscopy. In the high-energy region, the...

18. Experimental Inputs to the Hadronic Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon from BESIII

Max Lellmann (Johannes Gutenberg-Universität Mainz)

8/5/22, 5:20 PM

Despite being one of the most precisely studied observables in particle physics, there remains a discrepancy of 4.2$\sigma$ between the average value of the most recent direct measurements and the prediction within the Standard Model of the anomalous magnetic moment of the muon $a_\mu= (g−2)_\mu/2$. The precision of the prediction is limited by the knowledge of the hadronic contributions,...

17. Small Angle Initial State Radiation Analysis of the Pion Form Factor at BESIII

Ms Yasemin Schelhaas (JGU Mainz)

8/5/22, 5:40 PM

The anomalous magnetic moment of the muon $a_\mu=(g_\mu-2)/2$ is one of the most precisely measured variables in modern physics. However, there is a discrepancy of $4.2$ standard deviations between the Standard Model (SM) prediction and the experimental average of the latest direct measurements at BNL and FNAL, known as the Muon $(g-2)$-puzzle. For the SM prediction the main uncertainty arises...