Double-diffractive processes in high-resolution missing-mass experiments at the Tevatron

TL;DR

This work analyzes exclusive double-diffractive Higgs production in $pp$ and $p\bar{p}$ collisions, focusing on the missing-mass approach and the crucial role of central jet detection and $b$-tagging to suppress backgrounds. Using a perturbative QCD framework with unintegrated gluon densities and gap survival factors, the authors quantify the signal-to-background for $H\to b\bar{b}$ and find the Tevatron reach marginal, while the LHC offers more favorable prospects; nonetheless QED-driven backgrounds and the need for precise forward-proton measurements limit the feasibility of a pure missing-mass Higgs search. The paper also explores double-diffractive production of $\chi_c$ and $\chi_b$ as tests of the method, and highlights the strong potential of double-diffractive dijet production as a clean gluon factory due to the $J_z=0$ selection rule suppressing $q\bar{q}$-dijet backgrounds. Collectively, the results inform experimental strategies at hadron colliders, emphasizing that high-resolution missing-mass measurements must be complemented by decay-channel reconstruction and background control, while offering new avenues to study gluon-rich final states and heavy-quarkonia in a unique diffractive environment.

Abstract

We evaluate, in a model-independent way, the signal-to-background ratio for Higgs -> b bbar detection in exclusive double-diffractive events at the Tevatron and the LHC. For the missing-mass approach to be able to identify the Higgs boson, it will be necessary to use a central jet detector and to tag b quark jets. The signal is predicted to be very small at the Tevatron, but observable at the LHC. However we note that the background, that is double-diffractive dijet production, may serve as a unique gluon factory. We also give estimates for the double-diffractive production of chi_c and chi_b mesons at the Tevatron. We emphasize that a high-resolution missing-mass measurement, on its own, is insufficient to identify rare processes.

Figures (2)

• Figure 1: Schematic diagram of double-diffractive production of a system of invariant mass $M$, that is the process $pp \rightarrow p + M + p$.
• Figure 2: The rapidity distributions for double diffractive $\chi_c$ and $\chi_b$$(0^{++})$ production at the Tevatron.