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Title: Virtuality Distributions and Pion Transition Form Factor

Using the example of hard exclusive transition process γ*γ → π0 at the handbag level, we outline basics of a new approach to transverse momentum dependence in hard processes. In coordinate representation, matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p, are functions of (pz) and z2 parametrized through virtuality distribution amplitudes (VDA) Φ(x, σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+=0, we introduce the transverse momentum distribution amplitude (TMDA) Ψ(x, k_perp), and write it in terms of VDA Φ(x,σ). We propose models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data. We also discuss the generation of hard tails of TMDAs from initially soft forms.
Authors:
 [1]
  1. Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
OSTI Identifier:
1174200
Report Number(s):
JLAB-THY--14-1980; DOE/OR/23177-3214
Journal ID: ISSN 2010-1945; TRN: US1600056
Grant/Contract Number:
AC05-06OR23177
Type:
Accepted Manuscript
Journal Name:
International Journal of Modern Physics: Conference Series
Additional Journal Information:
Journal Volume: 37; Journal Issue: 2015; Conference: QCD Evolution Workshop (QCD 2014), Santa Fe, NM (United States), 12-16 May 2014; Journal ID: ISSN 2010-1945
Publisher:
World Scientific
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
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PIONS NEUTRAL; FORM FACTORS; TRANSVERSE MOMENTUM; MATRIX ELEMENTS; TRANSITION AMPLITUDES; PHOTON-PHOTON INTERACTIONS; QUANTUM OPERATORS