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Title: $${{\bar{d}} - {\bar{u}}}$$ Flavor Asymmetry in the Proton in Chiral Effective Field Theory

The $${\bar d - \bar u}$$ flavor asymmetry in the proton arising from pion loops is computed using chiral effective field theory. The calculation includes both nucleon and Δ intermediate states, and uses both the fully relativistic and heavy baryon frameworks. The x dependence of $${\bar d - \bar u}$$ extracted from the Fermilab E866 Drell–Yan data can be well reproduced in terms of a single transverse momentum cutoff parameter regulating the ultraviolet behavior of the loop integrals. In addition to the distribution at x > 0, corrections to the integrated asymmetry from zero momentum contributions are computed, which arise from pion rainbow and bubble diagrams at x = 0. These have not been accounted for in previous analyses, and can make important contributions to the lowest moment of $${\bar d-\bar u}$$ .
 [1] ;  [2] ;  [3] ;  [4]
  1. Institute of High Energy Physics, CAS, Beijing, 100049, China
  2. North Carolina State University, Raleigh, NC
  3. Jefferson Lab, Newport News, VA
  4. Theoretical Physics Center for Science Facilities, CAS, Beijing, 100049, China
Publication Date:
OSTI Identifier:
Report Number(s):
JLAB-THY-15-2048; DOE/OR/23177-3571
DOE Contract Number:
AC05-06OR23177; FG02-03ER41260
Resource Type:
Resource Relation:
Journal Name: Few Body Syst.; Journal Volume: 56; Journal Issue: 6-9; Conference: Light Cone 2014, Raleigh, North Carolina, USA, May 26-30, 2014
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States