Project to install roman pot detectors at 220 m in ATLAS

TL;DR

This paper outlines a project to install roman pot detectors at 220 m from the ATLAS interaction point to enable hard diffractive measurements at high luminosity and to complement the 420 m FP420 program. The approach builds on TOTEM experience, proposing horizontal roman pots at 216 and 224 m with silicon position detectors and precision timing within the pots, aiming for proton tagging and missing-mass reconstruction across a broad mass range. A detailed trigger concept integrates local roman pot triggers with ATLAS jets and leptons, proposing several 220 m and 420 m strategies and estimating L2 rates around 1 Hz at high luminosities. If realized during the 2009–2010 shutdown, this program would enhance Higgs-diffractive searches, diffractive structure studies, and photon-induced processes, improving mass resolution and background suppression through proton tagging and time-of-flight discrimination.

Abstract

We give a short description of the project to install roman pot detectors at 220 m from the interaction point in ATLAS. This project is dedicated to hard diffractive measurements at high luminosity.

Figures (2)

• Figure 1: Roman pot detector acceptance as a function of missing mass assuming a 10$\sigma$ operating positions, a dead edge for the detector of 50 $\mu m$ and a thin window of 200 $\mu m$.
• Figure 2: Principle of the L1 trigger using roman pot detectors at 220 m in the case of a Higgs boson decaying into $b \bar{b}$.