1. Bending crystals for magnetic and electric dipole moment measurements
Material from A. Stocchi (LAL Orsay), S. Redaelli, D. Mirachi, W. Scandale (CERN)

2. Introduction
Work presented here is from UA9 collaboration and LHC collimation team.
Main idea: crystals can be used to deflect hadrons:
To extract protons from LHC beam halo and send it to a target
To bend particles produced in a target and send them into an experiment
Different setups under consideration:
dedicated experiment at the SPS
re-using an existing experiment around the LHC ring, in parasitic mode

3. Bending of hadrons in crystal
Huge magnetic field used for precession measurements, see N. Neri talk

4. Circulating beam extraction tests at SPS

5. Circulating beam extraction tests at SPS
Major difficulty at the LHC

6. Crystal collimation at the LHC
Crystals can be used as collimators at the LHC

7. First proton channeling at 6.5 TeV

8. Crystals for dipole moment measurements
D.Mirarchi1, S. Redaelli1, W. Scandale1,2, A. Stocchi2.
1CERN, 2LAL.
“Physics Beyond Colliders Kickoff Workshop”, Geneva, September 6th and 7th 2016
Crystals for dipole moment measurements
Setup with two crystals: the first one deflects the beam halo to a target, the second one attached to the target produces a strong magnetic field where the moments of produced particles precess.

9. Proposal for a setup in the LHC
D.Mirarchi1, S. Redaelli1, W. Scandale1,2, A. Stocchi2.
1CERN, 2LAL.
“Physics Beyond Colliders Kickoff Workshop”, Geneva, September 6th and 7th 2016
Proposal for a setup in the LHC

10. Possible layout around LHCb
D.Mirarchi1, S. Redaelli1, W. Scandale1,2, A. Stocchi2.
1CERN, 2LAL.
“Physics Beyond Colliders Kickoff Workshop”, Geneva, September 6th and 7th 2016
Possible layout around LHCb

11. Losses expected in IR8-IR1
D.Mirarchi1, S. Redaelli1, W. Scandale1,2, A. Stocchi2.
1CERN, 2LAL.
“Physics Beyond Colliders Kickoff Workshop”, Geneva, September 6th and 7th 2016
Losses expected in IR8-IR1
These predicted losses are too high to allow parasitic running during LHC standard operation, a large reduction has to be obtained to be able to do so: major challenge

12. Conclusions
Successful tests of crystal channelling and collimation obtained in the last years at SPS and LHC
Use of double crystal setup for dipole moment measurement is compatible with LHC and LHCb geometry and acceptances, but a long way before a fully effective scenario
Next steps for the design:
Full layout
Compatibility with the LHC collimation system and with the LHCb detector because of losses
Optimize for the physics measurements:
The beam energy
The target and the crystal length to maximize the production of Λc and their channeling efficiency
The crystal bending angle for an optimal acceptance of the Λc fragments into LHCb
Investigate the alternative option of an experiment with an extracted beam (SPS or LHC)
Propose tests in the SPS and H8 in the North Area and then in the LHC, to investigate before LS2
The optimal assembly Target&Crystal2
The efficiency of the double crystal scenario
The compatibility with the crystal collimation scenario
the compatibility with LHCb and with the collimation system
The parasitic mode operation
The background and the data taking rates
Very challenging project and schedule