The pseudoscalar meson electromagnetic form factor at high Q2 from full lattice QCD

Koponen, J., Zimermmane-Santos, A.C., Davies, C.T.H. , Lepage, G.P. and Lytle, A.T. (2017) The pseudoscalar meson electromagnetic form factor at high Q2 from full lattice QCD. Physical Review D, 96(5), 054501. (doi: 10.1103/PhysRevD.96.054501)

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We give an accurate determination of the vector (electromagnetic) form factor, F(Q^2), for a light pseudoscalar meson up to squared momentum transfer Q^2 values of 6 GeV^2 for the first time from full lattice QCD, including u, d, s and c quarks in the sea at multiple values of the lattice spacing. Our results show good control of lattice discretisation and sea quark mass effects. We study a pseudoscalar meson made of valence s quarks but the qualitative picture obtained applies also to the \pi meson, relevant to upcoming experiments at Jefferson Lab. We find that Q^2F(Q^2) becomes flat in the region between Q^2 of 2 GeV^2 and 6 GeV^2, with a value well above that of the asymptotic perturbative QCD expectation, but well below that of the vector-meson dominance pole form appropriate to low Q^2 values. Our calculations show that we can reach higher Q^2 values in future to shed further light on where the perturbative QCD result emerges.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Lytle, Dr Andrew and Davies, Professor Christine and Koponen, Dr Jonna
Authors: Koponen, J., Zimermmane-Santos, A.C., Davies, C.T.H., Lepage, G.P., and Lytle, A.T.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN (Online):1550-2368
Published Online:05 September 2017
Copyright Holders:Copyright © 2017 American Physical Society
First Published:First published in Physical Review D 96(5):054501
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
630801Phenomenology from Lattice QCD and collider physicsChristine DaviesScience & Technology Facilities Council (STFC)ST/L000466/1S&E P&A - PHYSICS & ASTRONOMY