Improved nonrelativistic QCD for heavy-quark physics

Gp, Lepage; Magnea, Lorenzo; Nakhleh, Charles; Magnea, U.; Hornbostel, K.

doi:10.1103/physrevd.46.4052

Cited by 667 publications

(951 citation statements)

References 14 publications

(10 reference statements)

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“…There is a rule of power counting of v for the operatorsÔ n [11]. We will follow this approach to study the next-to-leading order corrections for the decay χ c0,2 → γγ.…”

Section: Introductionmentioning

confidence: 99%

Corrections for two photon decays of χc0 and χc2 and color octet contributions

Ma¹,

Wang²

2002

Physics Letters B

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Using the fact that the c-quark inside a charmonium moves with a small velocity v in the charmonium rest-frame, one can employ an expansion in v to study decays of charmonia and results at the leading order for χc0,2 → γγ exist in the literature. We study corrections at the next-to-leading order in the framework of nonrelativistic QCD(NRQCD) factorization. The study presented here is different than previous approaches where χc0,2 is taken as a bound-state of a cc pair and a nonrelativistic wave-function is used for the pair. We find that the corrections are consist not only of relativistic corrections, but also of corrections from Fock state components of χc0,2 in which the cc pair is in a color-octet state. For χc2 there is also a contribution from a Fock state component in which the pair is in a F-wave state. We determine the factorization formula for decay widths in the form of NRQCD matrix elements representing nonperturbative effects related to χc0,2, and calculate the perturbative coefficients at tree-level. Because the NRQCD matrix elements are unknown, a detailed prediction for the decay χc0,2 → γγ can not be made, but the effect of these corrections can be determined at certain level. Estimations show that the effect is significant and can not be neglected.

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“…There is a rule of power counting of v for the operatorsÔ n [11]. We will follow this approach to study the next-to-leading order corrections for the decay χ c0,2 → γγ.…”

Section: Introductionmentioning

confidence: 99%

Corrections for two photon decays of χc0 and χc2 and color octet contributions

Ma¹,

Wang²

2002

Physics Letters B

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“…This extrapolation effectively removes all the lattice artifacts including the (aΛ QCD ) n terms associated with the effect of lattice regularization on the dynamics at the confinement scale Λ QCD . 4 The problem of the perturbative matching breakdown, however, is not fully fixed by this procedure. Since the radiatively improved lattice result is supposed to be free of linear artifacts, the extrapolation is performed through a constrained fit of the data points by a polynomial in a with vanishing linear term.…”

Section: Jhep12(2017)007mentioning

confidence: 99%

“…The lattice simulations within the effective theory of nonrelativistic QCD (NRQCD) [1][2][3][4] has developed into one of the most powerful tools for the theoretical analysis of heavy quarkonium properties [5]. This method is entirely based on first principles, allows for simultaneous treatment of dynamical heavy and light quarks, and gives a systematic account of the long distance nonperturbative effects of the strong interaction.…”

Section: Introductionmentioning

confidence: 99%

Coulomb artifacts and breakdown of perturbative matching in lattice NRQCD

Penin

Rayyan

2017

J. High Energ. Phys.

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By studying an explicit analytical solution of the Schrödinger equation with the Coulomb potential on the lattice we demonstrate a breakdown of perturbative matching for the description of the Coulomb artifacts in lattice NRQCD, which leads to a large systematic error in the predictions for the heavy quarkonium spectrum. The breakdown is a result of a fine interplay between the short and long distance effects specific to the lattice regularization of NRQCD. We show how the problem can be solved by matching the lattice and continuum results for the solution of the full Schrödinger equation without the expansion in the Coulomb interaction.

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“…Therefore in NRQCD, the power counting is different from that of HQET [12,13], the two first terms of the effective Lagrangian are of order m Q v 2 and the third one (the 'spin' term) is of order m Q v 4 . The physical picture implies that the kinetic term cannot be treated as a small 1/m Q correction (as in HQET), but has to be included already at the leading order.…”

Section: Non Relativistic Qcdmentioning

confidence: 99%

“…On the lattice, this implies that the continuum limit cannot be taken. The authors of [13] gave an improvement program to reduce the errors below 10%. The principle is to add next to leading order corrections to this Lagrangian.…”

Section: Non Relativistic Qcdmentioning

confidence: 99%