Top quark pair and single top production at Tevatron and LHC energies

Top quark pair and single top production at Tevatron and LHC energies

Nikolaos Kidonakis 
Kennesaw State University, USA
E-mail: nkidonak@kennesaw.edu
Speaker.This work was supported by the National Science Foundation under Grant No. PHY 0855421.
Abstract

I present the latest calculations of total and differential cross sections for top-antitop pair production and single top quark production via all main partonic channels. Higher-order corrections from the resummation of soft gluons are added through NNLL accuracy. Detailed numerical results are presented for approximate NNLO cross sections and top quark transverse momentum distributions at the Tevatron and LHC colliders.

Top quark pair and single top production at Tevatron and LHC energies

 

Nikolaos Kidonakisthanks: Speaker. thanks: This work was supported by the National Science Foundation under Grant No. PHY 0855421.

Kennesaw State University, USA

E-mail: nkidonak@kennesaw.edu

\abstract@cs

35th International Conference of High Energy Physics July 22-28, 2010 Paris, France

1 Top quark production and NNLL resummation

Top quarks can be produced at hadron colliders via top-antitop pair [1] and single top [2] production channels. For production the leading-order (LO) partonic processes are , which is dominant at Tevatron energies, and , dominant at LHC energies. For single top quark production the corresponding processes are and (-channel), dominant at both Tevatron and LHC energies; (-channel), which is small at both Tevatron and LHC; and associated production, , which is very small at the Tevatron but significant at the LHC. A related process is .

QCD corrections are significant for both and single top production. Higher-order corrections from threshold resummation of soft-gluon contributions further enhance the total cross section and top quark differential distributions [3, 4, 5]. Recently these corrections have been resummed to next-to-next-to-leading logarithm (NNLL) accuracy, involving two-loop calculations of the soft anomalous dimensions. Approximate next-to-next-to-leading order (NNLO) total and differential cross sections have been derived from the NNLL resummed expressions [6, 7, 8]. Below I show numerical results for the cross section and the top quark distribution at Tevatron and LHC energies, and for single top production via -channel or via associated production with a or at Tevatron and LHC energies [7, 8].

2 cross section and top quark distribution at the Tevatron and the LHC

Figure 1: Top-antitop pair cross section at the Tevatron (left) and the LHC (right).

We first study the total cross section for production (Fig. 1). We derive an approximate NNLO cross section from the expansion of the NNLL resummed cross section. Using the MSTW2008 NNLO pdf [9], we find at Tevatron and LHC energies

At 14 TeV LHC collisions, we find pb. The first uncertainty is from scale variation by a factor of 2 around while the second is from the pdf [9] uncertainties.

Figure 2: Top quark distribution at the Tevatron (left) and the LHC (right).

The top quark transverse momentum distribution at the Tevatron and LHC is shown in Fig. 2.

3 Single top quark production: -channel and associated production

Figure 3: -channel single top cross section at the Tevatron (left) and LHC (right).

We continue with the -channel single top cross section at the Tevatron (Fig. 3, left). We find

The cross section for single -channel anti-top production at the Tevatron is identical.

The single top production cross section at the LHC in the -channel (Fig. 3, right plot) is

At 14 TeV, the result is .

For single antitop production at the LHC in the -channel we find pb at 7 TeV; and pb at 14 TeV.

Figure 4: (left) and (right) cross sections at the LHC.

The cross section for production at the LHC (see Fig. 4, left) is

At 14 TeV, we have pb. The NNLO approximate corrections increase the NLO cross section by %. The cross section for production is identical.

For production (Fig. 4, right) the NNLO approximate corrections increase the NLO cross section by to %.

References

  • [1] CDF Coll., F. Abe et al., Observation of Top Quark Production in Collisions with the Collider Detector at Fermilab, Phys. Rev. Lett. 74, 2626 (1995) [hep-ex/9503002]; D0 Coll., S. Abachi et al., Observation of the Top Quark, Phys. Rev. Lett. 74, 2632 (1995) [hep-ex/9503003].
  • [2] D0 Coll., V.M. Abazov et al., Observation of Single Top-Quark Production, Phys. Rev. Lett. 103, 092001 (2009), arXiv:0903.0850 [hep-ex]; CDF Coll., T. Aaltonen et al., Observation of Electroweak Single Top-Quark Production, Phys. Rev. Lett. 103, 092002 (2009), arXiv:0903.0885 [hep-ex].
  • [3] N. Kidonakis and R. Vogt, Theoretical top quark cross section at the Fermilab Tevatron and the CERN LHC, Phys. Rev. D 78, 074005 (2008), arXiv:0805.3844 [hep-ph].
  • [4] N. Kidonakis, Single top quark production at the Fermilab Tevatron: Threshold resummation and finite-order soft gluon corrections, Phys. Rev. D 74, 114012 (2006) [hep-ph/0609287]; Higher-order soft gluon corrections in single top quark production at the CERN LHC, Phys. Rev. D 75, 071501(R) (2007) [hep-ph/0701080].
  • [5] N. Kidonakis, Charged Higgs production via at the LHC, JHEP 05 (2005) 011 [hep-ph/0412422]; Higher order corrections to production, PoS (CHARGED2008) 003, arXiv:0811.4757 [hep-ph].
  • [6] N. Kidonakis, Two-loop soft anomalous dimensions and NNLL resummation for heavy quark production, Phys. Rev. Lett. 102, 232003 (2009), arXiv:0903.2561 [hep-ph]; Two-loop soft anomalous dimensions with massive and massless quarks, in DPF 2009, arXiv:0910.0473 [hep-ph]; Two-loop resummation for QCD hard scattering, PoS (DIS 2010) 115, arXiv:1005.3849 [hep-ph].
  • [7] N. Kidonakis, NNLL resummation for s-channel single top quark production, Phys. Rev. D 81, 054028 (2010), arXiv:1001.5034 [hep-ph]; Two-loop soft anomalous dimensions for single top quark associated production with a or , arXiv:1005.4451 [hep-ph].
  • [8] N. Kidonakis, NNLL resummation for QCD cross sections, in these proceedings; and in preparation.
  • [9] A.D. Martin, W.J. Stirling, R.S. Thorne, and G. Watt, Parton distributions for the LHC, Eur. Phys. J. C 63, 189 (2009), arXiv:0901.0002 [hep-ph].
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