Pion transition form factor in k(T) factorization
Jul, 2009
7 pages
Published in:
- Phys.Rev.D 80 (2009) 074024
e-Print:
- 0907.0166 [hep-ph]
Report number:
- DESY-09-100
View in:
Citations per year
Abstract: (arXiv)
It has been pointed out that the recent BaBar data on the pi gamma^* -> gamma transition form factor F_{pi gamma}(Q^2) at low (high) momentum transfer squared Q^2 indicate an asymptotic (flat) pion distribution amplitude. These seemingly contradictory observations can be reconciled in the k_T factorization theorem: the increase of the measured Q^2F_{pi gamma}(Q^2) for Q^2 > 10 GeV^2 is explained by convoluting a k_T dependent hard kernel with a flat pion distribution amplitude, k_T being a parton transverse momentum. The low Q^2 data are accommodated by including the resummation of alpha_s ln^2x, x being a parton momentum fraction, which provides a stronger suppression at the endpoints of x. The next-to-leading-order correction to the pion transition form factor is found to be less than 20% in the considered range of Q^2.- 12.39.St
- 13.40.Gp
- 12.38.Bx
- pi: form factor
- parton: transverse momentum
- correction: higher-order
- factorization: transverse momentum
- form factor: transition
- momentum transfer dependence
- quantum chromodynamics
References(78)
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