Exclusive vector-toponium photoproduction in hadronic collisions

TL;DR

This work assesses the feasibility of observing exclusive vector toponium photoproduction, $\\psi_t$, in hadronic collisions at LHC and FCC energies using a $k_T$-factorization framework with a Gaussian light-cone wave function for $\\psi_t$ and two unintegrated gluon distributions. The analysis combines the equivalent photon approximation for photon flux with a forward-amplitude calculation to predict $\\gamma p \\to \\psi_t \\otimes p$ cross sections and the rapidity distributions in $pp$ and $pPb$ collisions, finding cross sections of a few to tens of attobarns depending on energy and collider, and highlighting the severe experimental challenge due to a small dilepton branching ratio (≈$10^{-5}$). The study also discusses model dependencies on the UGD and notes the potential role of forward-proton detectors in isolating exclusive events, motivating further work on experimental strategies and more realistic detector conditions.

Abstract

An exploratory study of the exclusive production of a vector - toponium $ψ_t$ state by photon - hadron interactions is performed considering proton - proton and proton - nucleus collisions at the Large Hadron Collider (LHC) and Future Circular Collider (FCC) energies. The scattering amplitude is calculated using the $k_T$ - factorization formalism assuming that the vector - toponium state can be described by a Gaussian light-cone wave function and considering different models for the unintegrated gluon distribution. Predictions for the rapidity distributions and total cross - sections are presented. Our results indicate that the experimental measurement of this final state will be very difficult for the expected integrated luminosities at the LHC and FCC.

Figures (4)

• Figure 1: Exclusive vector - toponium photoproduction in $pp$ and $pPb$ collisions within the $k_T$ - factorization formalism.
• Figure 2: Predictions for the energy dependence of the exclusive $\psi_t$ photoproduction cross - section in photon - proton interactions, derived considering two different parameterizations for the proton unintegrated gluon distribution.
• Figure 3: Predictions for the rapidity distribution associated with the exclusive $\psi_t$ photoproduction in $pp$ collisions at the LHC (left panel) and FCC (right panel) energies. Predictions derived considering different parameterizations for the proton UGD.
• Figure 4: Predictions for the rapidity distribution associated with the exclusive $\psi_t$ photoproduction in $pPb$ collisions at the LHC (left panel) and FCC (right panel) energies. Predictions derived considering different parameterizations for the proton and nuclear UGD's.