Reassessing the importance of the colour-singlet contributions to direct J/ψ+WJ/ψ+W production at the LHC and the Tevatron - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Journal Articles Physics Letters B Year : 2014

Reassessing the importance of the colour-singlet contributions to direct J/ψ+WJ/ψ+W production at the LHC and the Tevatron

Abstract

We show that the colour-singlet contributions to the hadroproduction of J/ψJ/ψ in association with a W boson are sizable, if not dominant over the colour-octet contributions. They are of two kinds, sg→J/ψ+c+Wsg→J/ψ+c+W at View the MathML sourceαS3α and View the MathML sourceqq¯′→γ⋆/Z⋆W→J/ψW at order α3α3. These have not been considered in the literature until now. Our conclusion is that the hadroproduction of a J/ψJ/ψ in association with a W boson cannot be claimed as a clean probe of the colour-octet mechanism. The rate are small even at the LHC and it will be very delicate to disentangle the colour-octet contributions from the sizable colour-singlet ones and from the possibly large double-parton-scattering contributions. During this analysis, we have also noted that, for reactions such as the production of a J/ψJ/ψ by light quark-antiquark fusion, the colour-singlet contribution via an off-shell photon is of the order of the expectation from the colour-octet contribution via an off-shell gluon. This is relevant for inclusive production at low energies close to the threshold. Such an observation also likely extends to other processes naturally involving light-quark annihilation.

Dates and versions

in2p3-00957860 , version 1 (11-03-2014)

Identifiers

Cite

J.P. Lansberg, C. Lorcé. Reassessing the importance of the colour-singlet contributions to direct J/ψ+WJ/ψ+W production at the LHC and the Tevatron. Physics Letters B, 2014, 726, pp.218-222. ⟨10.1016/j.physletb.2013.07.059⟩. ⟨in2p3-00957860⟩
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