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Title: The frozen nucleon approximation in two-particle two-hole response functions

Here, we present a fast and efficient method to compute the inclusive two-particle two-hole (2p–2h) electroweak responses in the neutrino and electron quasielastic inclusive cross sections. The method is based on two approximations. The first neglects the motion of the two initial nucleons below the Fermi momentum, which are considered to be at rest. This approximation, which is reasonable for high values of the momentum transfer, turns out also to be quite good for moderate values of the momentum transfer q ≳kF. The second approximation involves using in the “frozen” meson-exchange currents (MEC) an effective Δ-propagator averaged over the Fermi sea. Within the resulting “frozen nucleon approximation”, the inclusive 2p–2h responses are accurately calculated with only a one-dimensional integral over the emission angle of one of the final nucleons, thus drastically simplifying the calculation and reducing the computational time. The latter makes this method especially well-suited for implementation in Monte Carlo neutrino event generators.
 [1] ; ORCiD logo [1] ;  [2] ;  [3] ;  [3] ;  [4]
  1. Univ. of Granada (Spain). Carlos I Inst. of Theoretical and Computational Physics and Dept. of Atomic, Molecular and Nuclear Physics
  2. Univ. of Turin and National Inst. of Nuclear Physics (INFN), Torino (Italy). Dept. of Atomic Physics
  3. Univ. of Seville (Spain). Dept. of Atomic Physics
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Center for Theoretical Physics and Lab. for Nuclear Science and Dept. of Physics
Publication Date:
Grant/Contract Number:
FC02-94ER40818; FIS2014-559386-P; FIS2014-53448-C2-1; FQM-225; FQM160; FQM7632
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 770; Journal Issue: C; Journal ID: ISSN 0370-2693
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE; Ministry of Economy, Industry and Competitiveness (MINECO); European Regional Development Fund (ERDF); National Inst. of Nuclear Physics (INFN); Regional Government of Andalusia
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 97 MATHEMATICS AND COMPUTING; Neutrino scattering; Meson-exchange currents; 2p–2h
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1427739