ALADDIN (An LHC Apparatus for Direct Dipole moments INvestigation) is a newly proposed compact fixed-target experiment at the LHC, designed to enable a unique program of measurements of charm baryon electromagnetic dipole moments.
The experiment relies on an innovative storage-ring layout capable of deflecting protons from the beam halo towards a solid target paired with a bent crystal, where forward-boosted charm baryons are produced and channelled.
By exploiting the spin precession induced by the channelling phenomenon in the bent crystal, both the magnetic and electric dipole moments can be measured through the analysis of the polarisation of the decaying $\Lambda^+_c$ and $\Xi^+_c$ charm baryons.
The ALADDIN apparatus features a 4.4 m-long spectrometer and a 20 m-long RICH detector for particle identification, to be installed at the LHC Insertion Region 3 without civil engineering work and with minimal impact on LHC operations, during the Long Shutdown 3 and following Year End Technical Stops (YETS), to start data taking in Run 4.
A proof-of-principle test at the LHC, named TWOCRYST, is currently underway to demonstrate the feasibility of the proposed experiment.
The Letter of Intent of the experiment has been submitted to the LHCC, and the Committee has approved the collaboration to prepare a Technical Proposal in 2026.