The frozen nucleon approximation in twoparticle twohole response functions
Abstract
Here, we present a fast and efficient method to compute the inclusive twoparticle twohole (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” mesonexchange currents (MEC) an effective Δpropagator averaged over the Fermi sea. Within the resulting “frozen nucleon approximation”, the inclusive 2p–2h responses are accurately calculated with only a onedimensional 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 wellsuited for implementation in Monte Carlo neutrino event generators.
 Authors:

 Univ. of Granada (Spain). Carlos I Inst. of Theoretical and Computational Physics and Dept. of Atomic, Molecular and Nuclear Physics
 Univ. of Turin and National Inst. of Nuclear Physics (INFN), Torino (Italy). Dept. of Atomic Physics
 Univ. of Seville (Spain). Dept. of Atomic Physics
 Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Center for Theoretical Physics and Lab. for Nuclear Science and Dept. of Physics
 Publication Date:
 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
 OSTI Identifier:
 1353496
 Alternate Identifier(s):
 OSTI ID: 1427739
 Grant/Contract Number:
 FC0294ER40818; FIS2014559386P; FIS201453448C21; FQM225; FQM160; FQM7632
 Resource Type:
 Journal Article: Published Article
 Journal Name:
 Physics Letters B
 Additional Journal Information:
 Journal Name: Physics Letters B Journal Volume: 770 Journal Issue: C; Journal ID: ISSN 03702693
 Publisher:
 Elsevier
 Country of Publication:
 Netherlands
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 97 MATHEMATICS AND COMPUTING; Neutrino scattering; Mesonexchange currents; 2p–2h
Citation Formats
Ruiz Simo, I., Amaro, J. E., Barbaro, M. B., Caballero, J. A., Megias, G. D., and Donnelly, T. W. The frozen nucleon approximation in twoparticle twohole response functions. Netherlands: N. p., 2017.
Web. doi:10.1016/j.physletb.2017.04.063.
Ruiz Simo, I., Amaro, J. E., Barbaro, M. B., Caballero, J. A., Megias, G. D., & Donnelly, T. W. The frozen nucleon approximation in twoparticle twohole response functions. Netherlands. doi:10.1016/j.physletb.2017.04.063.
Ruiz Simo, I., Amaro, J. E., Barbaro, M. B., Caballero, J. A., Megias, G. D., and Donnelly, T. W. Mon .
"The frozen nucleon approximation in twoparticle twohole response functions". Netherlands. doi:10.1016/j.physletb.2017.04.063.
@article{osti_1353496,
title = {The frozen nucleon approximation in twoparticle twohole response functions},
author = {Ruiz Simo, I. and Amaro, J. E. and Barbaro, M. B. and Caballero, J. A. and Megias, G. D. and Donnelly, T. W.},
abstractNote = {Here, we present a fast and efficient method to compute the inclusive twoparticle twohole (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” mesonexchange currents (MEC) an effective Δpropagator averaged over the Fermi sea. Within the resulting “frozen nucleon approximation”, the inclusive 2p–2h responses are accurately calculated with only a onedimensional 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 wellsuited for implementation in Monte Carlo neutrino event generators.},
doi = {10.1016/j.physletb.2017.04.063},
journal = {Physics Letters B},
issn = {03702693},
number = C,
volume = 770,
place = {Netherlands},
year = {2017},
month = {7}
}
Web of Science