Heavy quarkonium production through the semi-exclusivee+e−annihilation channels round theZ0peak

Abstract

Within the framework of the non-relativistic QCD, we present a detailed discussion on the heavy quarkonium production at the leading order in αs at a e + e − collider with the collision energy around the Z 0 peak. Quarkonia are produced through the semi-exclusive channels e + e − → |H QQ + X with X = QQ or gg, where Q indicates a heavy quark (respectively b or c). It is noted that in addition to the color-singlet 1S-level quarkonium states, the 2S and 1P color-singlet states and the color-octet |(QQ)[1 3 S1 ]g state also provide sizable contributions. The heavy quarkonium transverse momentum and rapidity distributions for the e + e − collision energy Ecm = mZ are presented. For both charmonium and bottomonium production via the Z 0 propagator, there is approximate "spin degeneracy" between the spin-triplet and spin-singlet quarkonium states. Uncertainties for the total cross sections are estimated by taking mc = 1.50 ± 0.15 GeV and m b = 4.90 ± 0.15 GeV. Around Ecm = mZ, due to the Z 0 -boson resonance effect, total cross sections for the channels via the Z 0 -propagator become much larger than the channels via the virtual photon propagator. We conclude that, in addition to the B factories as BaBar and Belle and the hadronic colliders as Tevatron and LHC, such a super Z-factory will present an excellent platform for studying the heavy quarkonium properties.

Exclusive charmonium production frome+e−annihilation round theZ0peak

“…We will not take the color-octet states into consideration, since it is noted that due to the colorsuppression for the hard scattering amplitude and also the suppression from the non-perturbative color-octet matrix element, the color-octet charmonium states shall give negligible contributions to those processes. This is somewhat different from the charmonium semi-exclusive processes, where the color-octet states indeed provide sizable contributions [39].…”

Inclusive productions of ϒ(1S,2S,3S) and χb(Sun1, Ma2 2019Phys. Rev. DSelf Cite6050View full textAdd to dashboardCite

“…1 Earlier studies of ϒ and χ b productions can be found in Refs. [2][3][4][5][6][7][8][9][10] and references therein, where the NRQCD predictions succeeded in explaining almost all the existing experimental measurements. However, considering the fact that the color-octet (CO) long distance matrix elements (LDMEs) that used to well explain the hadroprodution of J=ψ leads to dramatic discrepancies between the theoretical predictions and the measured total cross sections of e þ e − → J=ψ þ X non−cc from the BABAR and Belle collaborations [11], it is indispensable to take investigations on the ϒðnSÞ and χ b ðnPÞ productions in a variety of other processes to further test the validity and universality of the CO LDMEs.…”

Inclusive productions of $Υ(1S,2S,3S)$ and $χ_b(1P,2P,3P)$ via the Higgs boson decay

“…Earlier studies of Υ and χ b productions can be found in Refs. [2][3][4][5][6][7][8][9][10] and references therein, where the NRQCD predictions succeeded in explaining almost all the existing experimental measurements. However, considering the fact that the color-octet (CO) long distance matrix elements (LDMEs) that used to well explain the hadroprodution of J/ψ leads to dramatic discrepancies between the theoretical predictions and the measured total cross sections of e + e − → J/ψ + X non−cc from the BABAR and Belle collaborations [11], it is indispensable to take investigations on the Υ(nS) and χ b (nP ) productions in a variety of other processes to further test the validity and universality of the CO LDMEs.…”