* FíSICA NUCLEAR * Nuevo seminario de los martes

Dear Colleagues,

 

Please join us for our next Rising Researchers Tomorrow (October 3rd) at 10:30 AM Pacific Time by Xincheng Lin --- Duke University.

 

The seminar is fully virtual. Please find the Zoom link below.

 

Title: Cold radiative neutron-deuteron capture and Wigner-SU(4) Symmetry

 

Abstract: 

I will talk about cold radiative neutron-deuteron (nd) capture into a triton and a photon using pionless effective field theory (EFT) and Wigner-SU(4) symmetry. Cold nd capture is one of the simplest reactions involving three nucleons and an external current. The study of this process not only helps us better understand the electromagnetic properties of the three-nucleon bound states but is also crucial for studying more complicated processes, such as its isospin mirror process, the proton-deuteron capture into Helium-3 and a photon. We calculate radiative nd capture cross section fully perturbatively up to next-to-next-to-leading order (NNLO) in pionless EFT including contributions from electric and magnetic dipole (E1 and M1, respectively) transitions. The contribution from M1 transitions dominates at thermal neutron momentum, whereas that from E1 transitions dominates at higher energies. At NNLO we identify a new three-nucleon magnetic moment counterterm to renormalize both nd capture and the triton magnetic moment. In addition, I will talk about how the EFT power counting of nd capture cross section may be altered by expanding around the Wigner-SU(4) limit, where the binding momentum and effective range are the same for the deuteron and two-nucleon spin-singlet virtual state. This helps explain the sensitivity of nd capture cross section to the strength of the isovector two-nucleon magnetic current at thermal neutron momentum, as observed in both our study and previous potential-model calculations. I will also discuss some ongoing studies based on this work, such as polarization observables and parity violation in nd capture.

 

Zoom link:

https://us06web.zoom.us/j/85077701870

Sincerely,

Rising Researchers Seminar Series Committee