Improved determination of color-singlet nonrelativistic QCD matrix elements for<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>S</mml:mi></mml:math>-wave charmonium

Bodwin, Geoffrey T.; Chung, Hee Sok; Kang, Daekyoung; Lee, Jung-Il; Yu, Chaehyun

doi:10.1103/physrevd.77.094017

Cited by 142 publications

(234 citation statements)

References 43 publications

(107 reference statements)

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“…These numbers can be taken as estimates of the typical radius of the bound state system and of the typical velocity of the heavy quarks inside the bound state. It is comforting that the numbers we obtain for v 2 are similar to those usually assigned either by potential models or by NRQCD (see, for instance, [45,46]). The specific values in the table have been taken from the N = 3 case at ν = 1.5 GeV (and ν f = ν r = 0.7 GeV).…”

Section: Applicability Of Weak Coupling To Heavy Quarkoniummentioning

confidence: 50%

Improved determination of heavy quarkonium magnetic dipole transitions in potential nonrelativistic QCD

Pineda

Segovia

2013

Phys. Rev. D

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We compute the magnetic dipole transitions between low-lying heavy quarkonium states in a modelindependent way. We use the weak-coupling version of the effective field theory named potential NRQCD with the static potential exactly incorporated in the leading order Hamiltonian. The precision we reach is k 3 γ /m 2 ×O(α 2 s , v 2 ) and k 3 γ /m 2 ×O(v 4 ) for the allowed and forbidden transitions respectively, where k γ is the photon energy. We also resum the large logarithms associated with the heavy quark mass scale. The specific transitions considered in this paper are the following:The effect of the new power counting is found to be large and the exact treatment of the soft logarithms of the static potential makes the factorization scale dependence much smaller. The convergence for the bb ground state is quite good, and also quite reasonable for the cc ground state and the bb 1P state. For all of them we give solid predictions. For the 2S decays the situation is less conclusive, yet our results are perfectly consistent with existing data, as the previous disagreement with experiment for the Υ(2S) → η b (1S) γ decay fades away. We also compute some expectation values like the electromagnetic radius, r 2 , or p 2 .We find r 2 to be nicely convergent in all cases, whereas the convergence of p 2 is typically worse.

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Section: Applicability Of Weak Coupling To Heavy Quarkoniummentioning

confidence: 50%

Improved determination of heavy quarkonium magnetic dipole transitions in potential nonrelativistic QCD

Pineda

Segovia

2013

Phys. Rev. D

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“…Although there is an intrinsic limitation that the resummation of relativistic corrections with only the QQ Fock-state contributions eventually has the predictive power up to corrections of relative order v 4 Q [18], the method is still useful to improve the convergence in a process involving significant relativistic corrections. Such an example is the exclusive J/ψ + η c production in e + e − annihilation [10].…”

Section: Nrqcd Factorization Formulamentioning

confidence: 99%

“…Thus this relation holds for both spin-singlet and -triplet states independently of the index i up to corrections of v 2 Q that break the heavy-quark spin symmetry. This relation has been applied to determine the NRQCD matrix elements for the S-wave quarkonium states precisely [18,25] and to resum the relativistic corrections in various quarkonium processes [10,23,26].…”

Section: Nrqcd Factorization Formulamentioning

confidence: 99%

“…2 In addition, we also neglect the electromagnetic decay mode such as η b → γ * γ * → J/ψ + J/ψ that is tiny compared with the QCD mode. 3 Relativistic corrections are computed by making use of the generalized Gremm-Kapustin relation [18] that has been employed to resolve the e + e − → J/ψ + η c puzzle [10]. The method enables us to resum a class of color-singlet contributions to all orders in v 2 Q .…”

Section: Introductionmentioning

confidence: 99%

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Relativistic corrections to the exclusive decays ofC-even bottomonia intoS-wave charmonium pairs

Sang¹,

Rashidin

Kim³

et al. 2011

Phys. Rev. D

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Within the nonrelativistic quantum chromodynamics (NRQCD) factorization formalism, we compute the relativistic corrections to the exclusive decays of bottomonia with even charge conjugation parity into S-wave charmonium pairs at leading order in the strong coupling constant. Relativistic corrections are resummed for a class of color-singlet contributions to all orders in the charm-quark velocity v c in the charmonium rest frame. Almost every process that we consider in this work has negative relativistic corrections ranging from −20 to −35 %. Among the various processes, the relativistic corrections of the next-to-leading order in v c to the decay rate for χ b2 → η c (mS) + η c (nS) with m, n = 1 or 2 are very large. In every case, the resummation of the relativistic corrections enhances the rate in comparison with the next-to-leading-order results. We compare our results with available predictions based on the NRQCD factorization formalism. The NRQCD predictions are significantly smaller than those based on the light-cone formalism by 1 or 2 orders of magnitude.

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“…Recently, a method to resum a class of relativistic corrections to S-wave quarkonium processes has been developed [21,22], where order-α s and resummed relativistic corrections are included in the NRQCD factorization formula for the leptonic decay width. This method has been used to determine the color-singlet NRQCD matrix elements for the S-wave charmonium states [22,23] and to the calculation of exclusive twocharmonium production in e + e − annihilation [24,25]. Using the method given in Ref.…”

Section: Nrqcd Matrix Elementsmentioning

confidence: 99%

Inclusive charm production inΥ(nS)decay

et al. 2007

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Based on the NRQCD factorization formalism, we calculate the inclusive charm production rate in Υ(nS) decay at leading order in the strong coupling constant α s and the relative velocity v of the b quark in the quarkonium rest frame. The branching fractions for Υ(nS) to charm for n = 1, 2, and 3 are all around 7-9%. About 60% of the branching fraction into charm is from annihilation of the color-singlet bb pair into γ * → cc. Most of the remaining branching fraction is from annihilation of the color-singlet bb pair decaying into ccgg. We also compute the momentum distributions of the charm quark and charmed hadrons in the decays. The virtual-photon contribution to the charm quark momentum distribution is concentrated at the end point while the ccgg contribution is broad. The momentum distributions for charmed hadrons are obtained by convolving the charmquark momentum distribution with charm fragmentation functions. This makes the momentum distributions for charmed hadrons softer than that for the charm quark. This effect is particularly significant in the virtual-photon contribution.

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Improved determination of color-singlet nonrelativistic QCD matrix elements forS-wave charmonium

Cited by 142 publications

References 43 publications

Improved determination of heavy quarkonium magnetic dipole transitions in potential nonrelativistic QCD

Improved determination of heavy quarkonium magnetic dipole transitions in potential nonrelativistic QCD

Relativistic corrections to the exclusive decays ofC-even bottomonia intoS-wave charmonium pairs

Inclusive charm production inΥ(nS)decay

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