Year-end Sale % OFF 
Abstract
In this paper we discuss the systematics of quarkonium production at the LHC. In particular, we focus on the necessity to sum logs of the form log(Q/p_perp) and log(p_perp/m_Q). We show that the former contributions are power suppressed, while the latter, whose contribution in fragmentation is well known, also arise in the short distance (i.e., non-fragmentation) production mechanisms. Though these contributions are suppressed by powers of m_Q/p_perp, they can be enhanced by inverse powers of v, the relative velocity between heavy quarks in the quarkonium. In the limit p_perp >> m_Q short distance production can be thought of as the fragmentation of a pair of partons (i.e., the heavy quark and anti-quark) into the final state quarkonium. We derive an all order factorization theorem for this process in terms of double parton fragmentation functions (DPFF) and calculate the one-loop anomalous dimension matrix for the DPFF.
Highlights
C B In this paper we discuss the systematics of quarkonium production at the LHC
We show that the W R former contributions are power suppressed, while the latter, whose contribution in fragmentation IE T is well known, arise in the short distance production mechanisms
V IS Though these contributions are suppressed by powers of mQ/p⊥, they can be enhanced by inverse powers of v, the relative velocity between heavy quarks in the quarkonium
Summary
The inclusive differential cross section for the production of a quarkonium state H with mass MH , four-momentum p and transverse momentum p⊥ via the collision of two incoming hadrons, h1 and h2, with momentum p1 and p2, respectively, is: dσ dp2⊥. We have kept only the contributions that lead to a non-vanishing matrix element at leading power This operator scales as λ6 and can produce a QQpair through a time ordered product with an O(λ0) interaction term from the SCETm Lagrangian. There are power corrections to the DPFF that scale as λ4 (and higher) relative to the gluon fragmentation function Such sub-leading DPFFs could for example have the form of the leading DPFF with factors of the SCET covariant derivative inserted or have explicit factors of the quarkonium mass. Futhermore, the vacuum matrix element of the fragmentation operator in Eq (15) can be related to the standard fragmentation function that gives the probability of finding in the gluon a quarkonium state H moving in the n′ direction with large light-cone momentum n′ · p:. Our result agrees with the factorization formula in Ref. [10]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
