Physics Motivation

We propose to instrument the existing ALICE detector with a forward calorimeter system (FoCal), enabling a new and unique program at the LHC focused on small-x gluon dynamics of hadrons and nuclei. The FoCal detector is a highly-granular Si+W electromagnetic calorimeter combined with a conventional sampling hadronic calorimeter, covering the pseudorapidity interval of 3.4 < η < 5.5. The FoCal design is optimized to measure isolated photons at most forward rapidity for pT < 20 GeV/c. The FoCal will provide theoretically well-motivated observables in pp and p–Pb which are sensitive to the gluon distribution at small x at low to moderate Q^2, based on isolated photon, neutral meson, and jet production and correlations in hadronic collisions, and the measurement of vector meson photoproduction in ultra-peripheral collisions. The FoCal scientific program provides a broad exploration of gluon dynamics and non-linear QCD evolution at the lowest values of Bjorken x that will be accessible at any current or near-future facility world-wide. The FoCal measurements, combined with the comprehensive experimental program at the EIC and other forward measurements at RHIC and the LHC, will enable incisive test of the universality of linear and non-linear QCD evolution in different collision systems over an unprecedented kinematic range. The FoCal will also carry out measurements at very forward rapidity in Pb–Pb collisions, enabling novel probes of the Quark-Gluon Plasma based on jet quenching phenomena and long-range correlations of neutral pions, jets, and photons. 

Documents

A full list of FoCal documentation can be found here.

The FoCal Letter of Intent, completed June 2020, can be found here.

The FoCal Science Proposal, sent to the DOE for a Science Review on January 25th, 2023, can be found below.  

Link to the ALICE Barrel Tracking Upgrade Project Site

Physics Motivation

Complete the physics program with new/improved measurements of QGP properties. Take the advantage of ALICE PID and jet reconstruction capabilities and the LHC runs with high-interaction rates at the highest energies:

• Rates: inspect full luminosity - improve read out rates of TPC preserving other capabilities; new ITS

• New/improved precision measurements: new ITS

ALICE-USA interest drive some of the key measurements

• Jet-quenching: heavy-flavor production in jets (leading, sub-leading) – strong synergy with EMCal/DCal and USA physics lead

• Thermalization, heavy-quarks-medium coupling: baryon/meson ratio in the charm sector and charm flow; details of identified particle production – enabled by ITS and TPC Upgrades