A Gas Target Internal to the LHC for the Study of pp Single-Spin Asymmetries and Heavy Ion Collisions

Abstract

We discuss the application of an open storage cell as gas target for a proposed LHC fixed-target experiment AFTER@LHC. The target provides a high areal density at minimum gas input, which may be polarized1H,2H, or3He gas or heavy inert gases in a wide mass range. For the study of single-spin asymmetries in pp interaction, luminosities of nearly 1033/cm2 s can be produced with existing techniques.

Studies of various physics effects on an on-axis LHCD experiment using numerical tools

“…In such a case, the target [104] consists of a polarised or unpolarised gas source in combination with…”

Physics opportunities with a fixed target experiment at the LHC (AFTER@LHC)

“…In the gas target case, the full LHC proton or lead flux is used. The gas-jet [13] and storage cell [14] setups can provide a target areal density as high as 10 15 − 10 16 cm −2 with unpolarised hydrogen, i.e. an increase by three to four order of magnitude with respect to SMOG.…”

Physics case for a polarised target for AFTER@LHC

“…We stress that the current gas pressure is limited by the pumping system. Using a system like the one of the HERMES experiment at DESY-HERA [27], higher pressures can be obtained with the further possibility of polarised gases [28].…”

“…By reusing a target like that of HERMES, the effective polarisation of H or D [28] can be as high as 0.8 ( 3 He can also be used). In the case of an extracted beam, different choices for polarised targets are possible.…”