1 / 22

Compton Scattering on Light Nuclei (A=2,3) Deepshikha Shukla UNC-Chapel Hill

Compton Scattering on Light Nuclei (A=2,3) Deepshikha Shukla UNC-Chapel Hill. Collaborators: H. Griesshammer ( George Washington U .), J. McGovern ( U. Manchester ), D. Phillips ( Ohio U .) Previous Work:

mandell
Télécharger la présentation

Compton Scattering on Light Nuclei (A=2,3) Deepshikha Shukla UNC-Chapel Hill

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Compton Scattering on Light Nuclei (A=2,3)Deepshikha ShuklaUNC-Chapel Hill Collaborators: H. Griesshammer (George Washington U.), J.McGovern (U. Manchester), D. Phillips (Ohio U.) Previous Work: Beane/Malheiro/McGovern/Phillips/VanKolck; Griesshammer/Hemmert/Hildebrandt/Pasquini/Phillips; Choudhury(Shukla)/Phillips. Choudhury(Shukla)/Nogga/Phillips

  2. NEUTRON l~1Å l~few fm l~1 fm Compton Scattering FB19: Compton Scattering on Light Nuclei

  3. Spin-independent Spin-dependent Polarizabilities FB19: Compton Scattering on Light Nuclei

  4. Light Nuclei (?) • A=2,3: Access Neutron polarizabilities • Not charged • No ‘free neutron’ targets • Computable problem • Ongoing and planned experiments for both processes • At these energies, cPT is an effective tool FB19: Compton Scattering on Light Nuclei

  5. O(e2P2): N2LO J. McGovern (2001) (da, db) Ingredients- 1B mechanisms O(e2): LO Bernard, Kaiser, Meissner (1992) O(e2P): NLO FB19: Compton Scattering on Light Nuclei

  6. HBcPT for Compton Scattering on light Nuclei • Chiral expansion for • Naïve dimensional analysis- • Pn for a vertex with n powers of p or mp • P-2 for pion propagator (1/(p2-mp2)) • P-1 for nucleon propagator (1/(E-p2/2M)) • P4 for loop (loop integral) • P3 for a two-body diagram (d3(p2’-p2) absent) • Wavefunction derived from chiral potential or from potential model FB19: Compton Scattering on Light Nuclei

  7. Ingredients- 2B mechanisms O(e2P: NLO) Beane, Malheiro, Phillips, VanKolck (1999) O(e2P2: N2LO) Beane, Malheiro, McGovern, Phillips, VanKolck (2003) FB19: Compton Scattering on Light Nuclei

  8. Unpolarized gd at O(e2P2) Beane, Malheiro, McGovern, Phillips, VanKolck (2003) FB19: Compton Scattering on Light Nuclei

  9. Ingredients – D explicitly Small Scale Expansion (SSE) – e: D/Lc~mp/Lc; D = MD-MN Hemmert, Holstein, Kambor (1997) + Knochlein (1998) O(e3): NLO (da, db) Alternative – d-counting: Pascalutsa, Phillips (2003) FB19: Compton Scattering on Light Nuclei

  10. Ingredients – Low-energy resummation Griesshammer, Hemmert, Hildebrandt (2005) gd only: 1B NLO: 2B FB19: Compton Scattering on Light Nuclei

  11. Unpolarized gd at O(e3)+Low-energy resumm. Griesshammer, Hemmert, Hildebrandt (2005) FB19: Compton Scattering on Light Nuclei

  12. Current Efforts: Polarized gd - O(e3 )+Low-energy resumm. Griesshammer, McGovern, Phillips, Shukla (2009) Slide from H. Griesshammer FB19: Compton Scattering on Light Nuclei

  13. Polarized gd - O(e3 )+Low-energy resumm. FB19: Compton Scattering on Light Nuclei

  14. Polarized gd - O(e3 )+Low-energy resumm. FB19: Compton Scattering on Light Nuclei

  15. Ongoing Efforts • Comprehensive N2LO calculation with O(d4) effects and low-energy resummation. • Map out all(?) possible observables in the entire kinematic range - would serve as a guide for future experiments (MAxLab, HIgS, MAMI). FB19: Compton Scattering on Light Nuclei

  16. g3He at O(e2P) at 120 MeV (cm) Choudhury, Nogga, Phillips PRL98 (2007) 232303 FB19: Compton Scattering on Light Nuclei

  17. FB19: Compton Scattering on Light Nuclei

  18. FB19: Compton Scattering on Light Nuclei

  19. HIS projection with polarized 3He target Slide from H.Gao 16 NaI Photon flux: 5*107/s, target 1.0*1022/cm2, 45% polarization 500 hours FB19: Compton Scattering on Light Nuclei

  20. Summary & Future Direction • Elastic scattering on A=2,3– “promising” avenue to extract neutron polarizabilities. • We have taken the first step with gHe-3 • Delta degree of freedom • Low-energy resumm. • Comprehensive NNLO gd calculations in progress • Waiting for experimental data! FB19: Compton Scattering on Light Nuclei

  21. 2 p12 q 1 3 O(Q3) O(Q3) FB19: Compton Scattering on Light Nuclei

  22. FB19: Compton Scattering on Light Nuclei

More Related