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Title: QCD constituent counting rules for neutral vector mesons

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Journal Article: Published Article
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 97; Journal Issue: 3; Related Information: CHORUS Timestamp: 2018-02-08 13:23:40; Journal ID: ISSN 2470-0010
American Physical Society
Country of Publication:
United States

Citation Formats

Brodsky, Stanley J., Lebed, Richard F., and Lyubovitskij, Valery E. QCD constituent counting rules for neutral vector mesons. United States: N. p., 2018. Web. doi:10.1103/PhysRevD.97.034009.
Brodsky, Stanley J., Lebed, Richard F., & Lyubovitskij, Valery E. QCD constituent counting rules for neutral vector mesons. United States. doi:10.1103/PhysRevD.97.034009.
Brodsky, Stanley J., Lebed, Richard F., and Lyubovitskij, Valery E. Thu . "QCD constituent counting rules for neutral vector mesons". United States. doi:10.1103/PhysRevD.97.034009.
title = {QCD constituent counting rules for neutral vector mesons},
author = {Brodsky, Stanley J. and Lebed, Richard F. and Lyubovitskij, Valery E.},
abstractNote = {},
doi = {10.1103/PhysRevD.97.034009},
journal = {Physical Review D},
number = 3,
volume = 97,
place = {United States},
year = {Thu Feb 08 00:00:00 EST 2018},
month = {Thu Feb 08 00:00:00 EST 2018}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevD.97.034009

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  • QCD constituent counting rules define the scaling behavior of exclusive hadronic scattering and electromagnetic scattering amplitudes at high momentum transfer in terms of the total number of fundamental constituents in the initial and final states participating in the hard subprocess. The scaling laws reflect the twist of the leading Fock state for each hadron and hence the leading operator that creates the composite state from the vacuum. Thus, the constituent counting scaling laws can be used to identify the twist of exotic hadronic candidates such as tetraquarks and pentaquarks. Effective field theories must consistently implement the scaling rules in ordermore » to be consistent with the fundamental theory. Here in this paper, we examine how one can apply constituent counting rules for the exclusive production of one or two neutral vector mesons V 0 in e + e - annihilation, processes in which the V 0 can couple via intermediate photons. In the case of a (narrow) real V 0, the photon virtuality is fixed to a precise value s 1 = m2V 0, thus treating the V 0 as a single fundamental particle. Each real V 0 thus contributes to the constituent counting rules with NV0 = 1 . In effect, the leading operator underlying the V 0 has twist 1. Thus, in the specific physical case of single or double on-shell V 0 production via intermediate photons, the predicted scaling from counting rules coincides with vector-meson dominance (VMD), an effective theory that treats V 0 as an elementary field. However, the VMD prediction fails in the general case where the V 0 is not coupled through an elementary photon field, and then the leading-twist interpolating operator has twist NV 0 = 2 . Analogous effects appear in pp scattering processes.« less
  • We analyze the axial vector coupling of the constituent quark in the large-[ital N][sub [ital c]] limit and point out mechanisms which yield 1[minus][ital g][sub [ital A]][similar to][ital N][sub [ital c]][sup 0].
  • We propose sum rules for calculating the electronic widths of excited states of vector mesons of the Psi-, UPSILON-, and rho-meson families assuming that their mass values are known. The values of the electronic widths calculated agree with experiment.
  • QCD sum rules for vector mesons ({rho}, {omega}, {phi}) in nuclear matter are reexamined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays a crucial role in determining the validity of a sum rule. The uncertainties arising from less than precise knowledge of the condensate values and other input parameters are analyzed via a Monte Carlo error analysis. Our analysis leaves no doubt that vector-meson masses decrease with increasing density. This resolves the current debate over the behavior of the vector-meson masses and the sum rulesmore » to be used in extracting vector meson properties in nuclear matter. We find a ratio of {rho}-meson masses of {ital m}{sub {rho}}{sup *}/{ital m}{sub {rho}}=0.78{plus_minus}0.08 at nuclear matter saturation density.« less
  • Mass shift of vector mesons in the nuclear medium is studied in two different approaches: the in-medium QCD sum-rule approach and the scattering-length approach. The latter is shown to be inapplicable to extract the hadron masses in the medium. Further elaboration of the in-medium QCD sum rules is also discussed.