Relativistic pion loop corrections to the electromagnetic nucleon coupling

Conference · Tue Oct 01 04:00:00 EDT 2013

OSTI ID:1989785

Ji, Chueng ^[1]; Melnitchouk, Wolodymyr ^[2]

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1. North Carolina State University, Raleigh, NC (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

We present a relativistic formulation of pion loop corrections to the coupling of photons with nucleons on the light-front. Vertex and wave function renormalization constants are computed to lowest order in the pion field, including their nonanalytic behavior in the chiral limit, and studied numerically as a function of the ultraviolet cutoff. Particular care is taken to explicitly verify gauge invariance and Ward-Takahashi identity constraints to all orders in the m? expansion. The results are used to compute the chiral corrections to matrix elements of local operators, related to moments of deep-inelastic structure functions. Finally, comparisons of results for pseudovector and pseudoscalar coupling allows the resolution of a long-standing puzzle in the computation of pion cloud corrections to structure function moments.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1989785
• Report Number(s): JLAB-THY-14-2052; DOE/OR/23177-6701
• Country of Publication: United States
• Language: English