Ab initio Calculation of the np→dγ Radiative Capture Process
May 10, 20156 pages
Published in:
- Phys.Rev.Lett. 115 (2015) 13, 132001
- Published: Sep 24, 2015
e-Print:
- 1505.02422 [hep-lat]
Report number:
- INT-PUB-15-010,
- NT@UW-15-02,
- MIT-CTP-4666,
- JLAB-THY-15-2045
Citations per year
Abstract: (APS)
Lattice QCD calculations of two-nucleon systems are used to isolate the short-distance two-body electromagnetic contributions to the radiative capture process np→dγ, and the photo-disintegration processes γ(*)d→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 mπ∼450 and 806 MeV, and are combined with pionless nuclear effective field theory to determine the amplitudes for these low-energy inelastic processes. At mπ∼806 MeV, using only lattice QCD inputs, a cross section σ806 MeV∼17 mb is found at an incident neutron speed of v=2,200 m/s. Extrapolating the short-distance contribution to the physical pion mass and combining the result with phenomenological scattering information and one-body couplings, a cross section of σlqcd(np→dγ)=334.9(+5.2-5.4) mb is obtained at the same incident neutron speed, consistent with the experimental value of σexpt(np→dγ)=334.2(0.5) mb.- 12.38.Gc
- 11.15.Ha
- 13.40.Gp
- quark: mass dependence
- magnetic field: background
- gluon: interaction
- radiative capture
- nucleus
- quantum chromodynamics: lattice
- effective field theory
References(0)
Figures(3)
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