Relativistic correction to J/ψ and $ \varUpsilon $ pair production

Li, Yijie; Xu, Guang-Zhi; Liu, Kui-Yong; Zhang, Yu-Jie

doi:10.1007/jhep07(2013)051

Cited by 37 publications

(26 citation statements)

References 119 publications

(142 reference statements)

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“…The relativistic correction to the J/ψ pair production is carried out in Ref. [13], where the relativistic correction makes significant improvement for diluting the discrepancy between the shapes of color-singlet (CS) and color-octet (CO) differential cross sections at LO. Furthermore, the partial next-to-leading order (NLO ⋆ ) correction for J/ψ pair production is evaluated by Lansberg and Shao [14].…”

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confidence: 99%

Impact of J/ψ pair production at the LHC and predictions in nonrelativistic QCD

2016

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For J/ψ pair production at hadron colliders, we present the full next-to-leading order (NLO) calculations with the color-singlet channel in nonrelativistic QCD. We find that the NLO result can reasonably well describe the LHCb measured cross section, but exhibits very different behaviors from the CMS data in the transverse momentum distribution and mass distribution of J/ψ pair. Moreover, by adding contributions of gluon fragmentation and quark fragmentation, which occur at even higher order in αs, it is still unable to reduce the big differences. In particular, the observed flat distribution in the large invariant mass region is hard to explain. New processes or mechanisms are needed to understand the CMS data for J/ψ pair production. A. INTRODUCTIONNonrelativistic QCD (NRQCD) [1] is widely used in the study of heavy quarkonium physics. In NRQCD a quarkonium production process can be factorized as short-distance parton scattering amplitudes multiplied by long-distance matrix elements (LDMEs). This factorization has been applied in single quarkonium production and tested by various experiments [2][3][4][5][6][7].Besides the single quarkonium production, the multiquarkonuim production provides another ideal laboratory to understand the quarkonium production mechanism that NRQCD assumes. At the LHC, the LHCb Collaboration in 2011 measured the J/ψ pair production for the first time at the center-of-mass energy √ s = 7 TeV with an integrated luminosity of 35.2 pb −1 [8]. In 2013, the CMS Collaboration further released the data of J/ψ pair production[9] with a much larger transverse moment range, providing a good platform for testing the validity of NRQCD in quarkonium pair production.In Refs. [10][11][12], the leading order (LO) calculation of J/ψ pair production in the color singlet model (CSM) is performed. The relativistic correction to the J/ψ pair production is carried out in Ref. [13], where the relativistic correction makes significant improvement for diluting the discrepancy between the shapes of color-singlet (CS) and color-octet (CO) differential cross sections at LO. Furthermore, the partial next-to-leading order (NLO ⋆ ) correction for J/ψ pair production is evaluated by Lansberg and Shao [14]. They argue that the NLO ⋆ yield can approach the full NLO result at large p T , the transverse momentum of one of the two J/ψ's, and thus the NLO ⋆ results give a more precise theoretical prediction than the * Electronic address: sunliping@pku.edu.cn † Electronic address: hao.han@pku.edu.cn ‡ Electronic address: ktchao@pku.edu.cn LO results in this region. All the above works are performed in the single parton scattering (SPS) mechanism, while the contribution of double parton scattering (DPS) is assessed in Refs. [15][16][17], and is expected to be important. As predictions for DPS are very model-dependent [15][16][17], it is needed to have an accurate calculation for SPS contribution before one can extract the DPS contribution.In order to further understand the multi-quarkonium production mechanism, it is neces...

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confidence: 99%

Impact of J/ψ pair production at the LHC and predictions in nonrelativistic QCD

2016

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“…The leading-order color-singlet and color-octet contributions for the differential cross sections of the gg → H 1 H 2 subprocess were calculated by several authors in the nonrelativistic approximation [7][8][9][10][11][12][13][14] and more recently by taking into account the relativistic effects [15,17] and higher-order corrections [16,19,20]. As the impact of the relativistic effects is still a theme of debate [15,17] and the higher-order corrections are predicted to modify the transverse momentum distribution at large p T [16,19,20], in our calculations for the diffractive production, we will estimate the differential cross sections at leading order, disregarding these corrections.…”

Section: Formalismmentioning

confidence: 99%

“…As the impact of the relativistic effects is still a theme of debate [15,17] and the higher-order corrections are predicted to modify the transverse momentum distribution at large p T [16,19,20], in our calculations for the diffractive production, we will estimate the differential cross sections at leading order, disregarding these corrections. We will follow the notation from Refs.…”

Section: Formalismmentioning

confidence: 99%

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Double heavy quarkonium production in diffractive processes at the Run 2 LHC energy

2018

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The double quarkonium production in single and double diffractive processes is investigated considering pp collisions at the Run 2 LHC energy. Using the nonrelativistic QCD factorization formalism for the quarkonium production and the resolved Pomeron model to describe the diffractive processes, we estimate the rapidity and transverse momentum dependencies of the cross sections for the J=ΨJ=Ψ and ϒϒ production. The contributions of the color-singlet and color-octet channels are estimated, and predictions for the total cross sections in the kinematical regions of the LHC experiments are also presented. Our results demonstrate that the double quarkonium production in diffractive processes is not negligible and that its study can be useful to test the underlying assumptions present in the description of the single and double diffractive processes.

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“…The next-to-leading order (NLO) radiative corrections to the heavy quarkonium production [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] and polarization [54][55][56][57][58][59] at hadron colliders are significant. And the NLO relativistic corrections to J/ψ hadronic production are considered too [60][61][62]. O(α s v 2 ) corrections to the decays of h c , h b and η b are studied in refs.…”

Section: Introductionmentioning

confidence: 99%

Relativistic correction to J/ψ and $ \varUpsilon $ pair production

Cited by 37 publications

References 119 publications

Impact of J/ψ pair production at the LHC and predictions in nonrelativistic QCD

Impact of J/ψ pair production at the LHC and predictions in nonrelativistic QCD

Double heavy quarkonium production in diffractive processes at the Run 2 LHC energy

α s v 2 corrections to η c and χ cJ production recoiled with a photon at e + e − colliders

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