Ab initio calculation of the $$np \to d ³$$ radiative capture process
In this study, lattice QCD calculations of two-nucleon systems are used to isolate the short-distance two-body electromagnetic contributions to the radiative capture process $$np \to d\gamma$$, and the photo-disintegration processes $$\gamma^{(\ast)} d \to np$$. In nuclear potential models, such contributions are described by phenomenological meson-exchange currents, while in the present work, they are determined directly from the quark and gluon interactions of QCD. Calculations of neutron-proton energy levels in multiple background magnetic fields are performed at two values of the quark masses, corresponding to pion masses of $$m_\pi \sim 450$$ and 806 MeV, and are combined with pionless nuclear effective field theory to determine these low-energy inelastic processes. Extrapolating to the physical pion mass, a cross section of $$\sigma^{lqcd}(np\to d\gamma)=332.4({\tiny \begin{array}{l}+5.4 \\ - 4.7\end{array}})\ mb$$ is obtained at an incident neutron speed of $$v=2,200\ m/s$$, consistent with the experimental value of $$\sigma^{expt}(np \to d\gamma) = 334.2(0.5)\ mb$$.
- Authors:
-
[1]
; [1]
; [2]
; [3]
; [4]
; [1]
; [5]
- Univ. of Washington, Seattle, WA (United States)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Univ. of Barcelona, Barcelona (Spain)
- The City College of New York, New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
- Publication Date:
- Report Number(s):
- JLAB-THY-15-2045; DOE/OR/23177-3346; arXiv:1505.02422
Journal ID: ISSN 0031-9007; PRLTAO
- Grant/Contract Number:
- OCI-1053575; PHY1206498; PHY12-05778; AC02-05CH11231; DOE DE-SC0013477; SC0010337-ER42045; FG02-04ER41302; FG02-00ER41132; AC05-00OR22725; SC0010495; AC05-06OR23177
- Type:
- Accepted Manuscript
- Journal Name:
- Physical Review Letters
- Additional Journal Information:
- Journal Volume: 115; Journal Issue: 13; Journal ID: ISSN 0031-9007
- Publisher:
- American Physical Society (APS)
- Research Org:
- Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
- Sponsoring Org:
- USDOE
- Contributing Orgs:
- NPLQCD Collaboration
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
- OSTI Identifier:
- 1221536
- Alternate Identifier(s):
- OSTI ID: 1224626
- Free Publicly Accessible Full Text
-
Accepted Manuscript (DOE)
- Publisher's Version of Record
- https://doi.org/10.1103/PhysRevLett.115.132001