Heavy pair production currents with general quantum numbers in dimensionally regularized nonrelativistic QCD

Hoang, André H.; Ruiz-Femenía, Pedro

doi:10.1103/physrevd.74.114016

Cited by 28 publications

(32 citation statements)

References 54 publications

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“…In fact, from the lower-energy effective field theory of NRQCD, Hoang and Ruiz-Femenia are able to predict the anomalous dimensions for NRQCD bilinear carrying general 2S+1 L J quantum number [37]. Particulary, the anomalous dimensions of the operators carrying quantum number 3 P J are predicted to be…”

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confidence: 92%

Next-to-next-to-leading-order QCD corrections to χc0,2→γγ

et al. 2016

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We calculate the next-to-next-to-leading-order (NNLO) perturbative corrections to P -wave quarkonia annihilation decay to two photons, in the framework of nonrelativistic QCD (NRQCD) factorization. The order-α 2 s short-distance coefficients associated with each helicity amplitude are presented in a semi-analytic form, including the "light-by-light" contributions. With substantial NNLO corrections, we find disquieting discrepancy when confronting our state-of-the-art predictions with the latest BESIII measurements, especially fail to account for the measured χc2 → γγ width. Incorporating the effects of spin-dependent forces would even exacerbate the situation, since it lifts the degeneracy between the nonperturbative NRQCD matrix elements of χc0 and χc2 toward the wrong direction. We also present the order-α 2 s predictions to χ b0,2 → γγ, which await the future experimental test. Charmonium decay has historically played an important role in establishing the asymptotic freedom of QCD, and served as a clean platform to probe the interplay between pertubative and nonperturbative dynamics [1,2]. Among them, the electromagnetic decay χ c0,2 → γγ provide a particularly interesting, and, rich testing ground of QCD [3,4]. In the past decades, these decay channels have been extensively studied from various theoretical angles, such as nonrelativistic potential model [5,6], relativistic quark model [7][8][9], Bethe-Salpeter approach [10], nonrelativistic QCD (NRQCD) factorization [11,12], as well as lattice QCD [13]. On the experimental side, they were previously measured by . BESIII experiment [15] has recently reported their high precision results, Γ γγ (χ c0 ) = (2.33 ± 0.20 ± 0.13 ± 0.17) keV, (1a) Γ γγ (χ c2 ) = (0.63 ± 0.04 ± 0.04 ± 0.04) keV. (1b)

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confidence: 92%

Next-to-next-to-leading-order QCD corrections to χc0,2→γγ

et al. 2016

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“…The analogous evolution equation for currents describing pairs of quarks and colored scalars in any angular momentum and spin state ( 2s+1 L J ) were derived recently in Ref. [11]. In Eq.…”

Section: Introductionmentioning

confidence: 99%

Two-loop ultrasoft running of theO(v2)QCD quark potentials

Hoang

Stahlhofen

2007

Phys. Rev. D

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“…For the 3 S 1 current coefficient c NLL 1 we have [10,54] A (1) We note that in Ref. [58] the NLL anomalous dimensions of color singlet heavy quark-antiquark production currents for all possible 2S+1 L J quantum numbers were determined.…”

Section: Discussionmentioning

confidence: 99%

“…The NLL result for c 3 can be found in Ref. [58]. For completeness we quote the NLL expressions for c 1,3 in Appendix A. Setting…”

Section: Form Factors In Vnrqcdmentioning

confidence: 99%

Fully-differential top-pair production at a lepton collider: from threshold to continuum

Bach

Nejad²,

Hoang

et al. 2018

J. High Energ. Phys.

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We present an approach to predict exclusive W + bW −b production at lepton colliders that correctly describes the top-anti-top threshold as well as the continuum region. We incorporate tt form factors for the NLL threshold resummation derived in NRQCD into a factorized relativistic cross section using an extended double-pole approximation, which accounts for fixed-order QCD corrections to the top decays at NLO. This is combined with the full fixed-order QCD result at NLO for W + bW −b production to obtain predictions that are not only valid at threshold but smoothly transition to the continuum region. Our implementation is based on the Monte Carlo event generator Whizard and the code Toppik and allows to compute fully-differential threshold-resummed cross sections including the interference with non-resonant background processes. For the first time it is now possible to systematically study general differential observables at future lepton colliders involving the decay products of the top quarks at energies close to the pair production threshold and beyond.

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Heavy pair production currents with general quantum numbers in dimensionally regularized nonrelativistic QCD

Cited by 28 publications

References 54 publications

Next-to-next-to-leading-order QCD corrections to χc0,2→γγ

Next-to-next-to-leading-order QCD corrections to χc0,2→γγ

Two-loop ultrasoft running of theO(v2)QCD quark potentials

Fully-differential top-pair production at a lepton collider: from threshold to continuum

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