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Moments of light-meson distribution amplitudes from lattice QCD

Moments of light-meson distribution amplitudes from lattice QCD
Moments of light-meson distribution amplitudes from lattice QCD

The distribution amplitudes of mesons parameterize their structure in partonic terms, at least insofar as that structure is relevant to collinearly-factprized exclusive processes: they essen- tially describe the valence Fock state's momentum distribution. Early applications were to form factors such as F%m(Q2) and Frrn(Q2), but the development of QCD factorization and the Soft Collinear Effective Theory has led to renewed interest motivated by flavour physics. The lowest moments of the distribution amplitudes can be calculated using Lattice QCD. As part of the UKQCD/RBC collaborations' Nf = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments for the pseudoscalar mesons % and K and the (longitudinally-polarized) vector mesons p, K* and </>, as well as the ratios of vector meson couplings fp /fp, fx*/fK* and fl/fy. We obtain the desired quantities with a good precision and our results are in reasonable agreement with other recent lattice and QCD sum rule calcu- lations (but with significantly smaller errors in the latter case). In particular, we are able clearly to discern the expected quark-mass dependence of SU(3) flavour breaking effects. An important part of this research programme is the non-perturbative renormalization of lattice operators using the RI/MOM technique. We describe both our successful renormaliza- tion of the quark bilinears (necessary for the vector meson couplings) and our ongoing efforts to overcome some fundamental issues with RI/MOM which currently prevent us from using non-perturbative renormalization for the distribution amplitude moments.

University of Southampton
Donnellan, Michael Anthony
9efd89a5-9cf5-44a5-a323-eccc2d9a37b3
Donnellan, Michael Anthony
9efd89a5-9cf5-44a5-a323-eccc2d9a37b3

Donnellan, Michael Anthony (2008) Moments of light-meson distribution amplitudes from lattice QCD. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

The distribution amplitudes of mesons parameterize their structure in partonic terms, at least insofar as that structure is relevant to collinearly-factprized exclusive processes: they essen- tially describe the valence Fock state's momentum distribution. Early applications were to form factors such as F%m(Q2) and Frrn(Q2), but the development of QCD factorization and the Soft Collinear Effective Theory has led to renewed interest motivated by flavour physics. The lowest moments of the distribution amplitudes can be calculated using Lattice QCD. As part of the UKQCD/RBC collaborations' Nf = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments for the pseudoscalar mesons % and K and the (longitudinally-polarized) vector mesons p, K* and </>, as well as the ratios of vector meson couplings fp /fp, fx*/fK* and fl/fy. We obtain the desired quantities with a good precision and our results are in reasonable agreement with other recent lattice and QCD sum rule calcu- lations (but with significantly smaller errors in the latter case). In particular, we are able clearly to discern the expected quark-mass dependence of SU(3) flavour breaking effects. An important part of this research programme is the non-perturbative renormalization of lattice operators using the RI/MOM technique. We describe both our successful renormaliza- tion of the quark bilinears (necessary for the vector meson couplings) and our ongoing efforts to overcome some fundamental issues with RI/MOM which currently prevent us from using non-perturbative renormalization for the distribution amplitude moments.

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Published date: 2008

Identifiers

Local EPrints ID: 466650
URI: http://eprints.soton.ac.uk/id/eprint/466650
PURE UUID: 37bb65ea-92b3-482f-a392-b0264fbbab2b

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Date deposited: 05 Jul 2022 06:14
Last modified: 16 Mar 2024 20:49

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Author: Michael Anthony Donnellan

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