Search

Sizable amounts of heavy quarkonium events can be produced through W boson decays at the LHC. Such channels will provide a suitable platform to study the properties of heavy quarkonium. The "improved trace technology," which disposes the amplitude M at the amplitude level, is helpful for deriving compact analytical results for complex processes. As an important new application, in addition to the production of the lower-level Fock states |(Q&Qmacr;)[lS]〉 and l(QQ')[lP]〉 we make a further study on the production of higher excited |(Q&Q')〉 quarkonium Fock states |(QQ')[2S]〉, |(QQ')[3S]〉, and |(QQ')[2P]〉. Here |(cc)) stands for charmonium, |(cb)〉 for quarkonium, and |(bb)〉 for bottomonium. We show that sizable amounts of events for those higher excited states can also be produced at the LHC. Therefore, we need to take them into consideration for a sound estimation. Assuming all excited heavy quarkonium states decay to the ground spin-singlet [l1S0] wave state with 100% efficiency via electromagnetic or hadronic interactions, we can obtain the total decay width by adding all of the mentioned Fock states together. As a result, at the LHC with the luminosity &Langran; 1034cm-2s-1 and the center-of-mass energy √S = 14 TeV, we observe that 8.7 × 106 &eegr;c and J/&psgr;, 4.3 × 105 Bc and B*c, 1.4 × 103 &eegr;c and &ggr; events per year can be obtained through W+ decays. [ABSTRACT FROM AUTHOR]

The production of the heavy (cc̅)-quarkonium, (cb̅)-quarkonium, and (bb̅)-quarkonium states [(QQ̅′) quarkonium for short], via the W+ semi-inclusive decays, has been systematically studied within the framework of the nonrelativistic QCD. In addition to the two color-singlet S-wave states, we also discuss the production of the four color-singlet P-wave states |(QQ̅′)(1P1)1⟩ and |(QQ̅′)(3PJ)1⟩ [with J=(0,1,2)] together with the two color-octet components |(QQ̅′)(1S0)8⟩ and |(QQ̅′)(3S1)8⟩. Improved trace technology is adopted to derive the simplified analytic expressions at the amplitude level, which shall be useful for dealing with the following cascade decay channels. At the LHC with the luminosity L∝1034  cm−2 s−1 and the center-of-mass energy √S=14  TeV, sizable heavy-quarkonium events can be produced through the W+ boson decays; i.e., 2.57×106 ηc, 2.65×106J/Ψ, and 2.40×106 P-wave charmonium events per year can be obtained, and 1.01×105 Bc, 9.11×104 Bc*, and 3.16×104 P-wave (cb̅)-quarkonium events per year can be obtained. Main theoretical uncertainties have also been discussed. By adding the uncertainties caused by the quark masses in quadrature, we obtain ΓW+→(cc̅)+cs̅=524.8+396.3−258.4  KeV, ΓW+→(cb̅)+bs̅=13.5+4.73−3.29  KeV, ΓW+→(cb̅)+cc̅=1.74+13.4+1.98−0.73  KeV, and ΓW+→(bb̅)+cb̅=38.6+13.4−9.69  eV. [ABSTRACT FROM AUTHOR]

Within the framework of nonrelativistic QCD, we present a detailed discussion on doubly heavy baryon production through the e+ e- annihilation channel, e+e- → γ/Z0 → ΞQQ' + Q̄ + Q̄', at a high luminosity e+e- collider. Here Q(') stands for the heavy b or c quark. In addition to the channel through the usually considered diquark state (QQ')[3S1]3... contributions from the channels through other equally important diquark states such as (QQ')[1S0]6 are also discussed. Uncertainties for the total cross sections are predicted by taking mc = 1.80 ± 0.30 GeV and mb = 5.10 ± 0.40 GeV. At a super-Z factory running around the Z0 mass and with a high luminosity up to L ∝1034 ~ 1036 cm-2 s-1 we estimate that about 1.1 × 105-7 Ξcc events, 2.6 × 105-7 Ξbc events, and 1.2 × 104-6 Ξbb events can be generated in one operation year. Such a Z factory, thus, will provide a good platform for studying doubly heavy baryons in a manner comparable to the CERN Large Hadron Collider. [ABSTRACT FROM AUTHOR]