Title: Extraction of $\gamma n\to \pi N$ observables from deuteron-target data

Abstract

In this work, an examination is conducted on a commonly used procedure for extracting (un)polarized γn → π^-p and γn → π⁰n observables from 2H(γ,π^-)pp and ²H(γ,π⁰)pn data, using a model that consists of the impulse term and the final-state interaction (FSI) terms due to nucleon and pion exchange. Recent experimental and theoretical analyses used an extraction method that does not impose a cut on the final πN invariant mass W. I demonstrate that the use of this method can result in the γn → πN observables that are seriously distorted by the nucleon Fermi motion, and that one can efficiently avoid this problem by imposing a cut on W. It is also shown that the use of kinematical cuts of recent experimental analyses can still leave in the selected samples substantial FSI effects that must be corrected in extracting the γn → πN cross sections. In terms of the nucleon- and pion-exchange mechanisms, I give the first qualitative explanation of the FSI corrections, obtained in a recent Mainz Microtron experiment, for extracting γn → π⁰n cross sections.

Authors:

Nakamura, Satoshi X. ^[1]

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+ Show Author Affiliations

1. Universidade Cruzeiro do Sul, São Paulo (Brazil)

Publication Date:

Tue Oct 02 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1544192

Alternate Identifier(s):

OSTI ID: 1475230

Grant/Contract Number:  

AC02-05CH11231; 2016/15618-8

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 98; Journal Issue: 4; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS