RECENT RESULTS FROM MICE ON MULTIPLE COULOMB SCATTERING AND ENERGY LOSS Alan Young* on behalf of the MICE Collaboration *a.r.young@strath.ac.uk Acknowledgemnts Work supported by NSF and DOE (USA), the INFN (Italy), the STFC (UK), the EC under the EC FP7, the Japan Society for the Promotion of Science (Japan) and the Swiss National Science Foundation (Switzerland), in the framework of the SCOPES programme. We gratefully acknowledge their support. We acknowledge the use of Grid computing resources deployed and operated by GridPP in the UK, http://www.gridpp.ac.uk/. MICE Data Links to the MICE raw data along with links to other MICE related data can be accessed at https://doi.org/10.17633/rd.brunel.3179644 References [1] S. Geer, “Neutrino beams from muon storage rings: Characteristics and physics potentials”, Phys. Rev. D57 (1998) 6989 [2] D. Neuffer, “Principles and applications of muon cooling”, Part. Accel. 14 (1983) 75 [3] R. C. Fernow and J. C. Gallardo. “Muon transverse ionization cooling: Stochastic approach”. Phys. Rev. E, 52:1039-1042, 1995 [4] MuScat Collaboration, W. J. Murray, “Comparison of MuScat data with GEANT4”, Nucl. Phys. Proc. Suppl. 149 (2005) p. 99-103 [5] GEANT4 Collaboration, S. Agostinelli et al., “GEANT4: A Simulation toolkit”, Nucl. Instrum. Meth. 265 A506 (2003) p. 250- 303 [6] S. Peter, “Particle penetration and radiation effects”. Springer Series in Solid State Sciences, 151. Berlin Heidelberg: Springer- Verlag Measurement of energy loss The mean rate of energy loss for relativistic charged heavy particles traversing matter is given by the “Bethe equation” [6] where the mean excitation energy I in hydrogen is known at the 5% level but has never been measured in lithium hydride. The momentum of the muons is measured upstream and downstream of the absorber using the scintillating-fibre trackers combined with the time of flight detectors. Preliminary results using a convolution fit for 200 MeV/c muons in magnetic field traversing the LiH absorber show that mean momentum loss is ∆p = 12.8 ± 5.3 MeV/c. Figure 3: Reconstructed momentum loss across the LiH absorber for several muon beams Figure 1: Layout of MICE in the Step IV configuration Ionization cooling equation Cooling term Heating term Introduction Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at a neutrino factory and to provide lepton- antilepton collisions at energies of up to several TeV at a muon collider [1]. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the technique by which the phase space volume occupied by muon beams is reduced (“cooled”) [2]. In an ionization-cooling channel, a muon beam passes through absorber material in which it loses energy. The longitudinal energy lost is then replaced using radio frequency (RF) cavities. The combined effect of energy loss and re-acceleration is to reduce the transverse emittance of the beam (transverse cooling). The configuration that has operated until December 2017 at the Rutherford Appleton Laboratory, has made detailed measurements of multiple Coulomb scattering and energy loss of muons in lithium hydride (LiH) and liquid hydrogen (LH2) absorbers, over a range of momenta from 140 to 240 MeV/c with and without magnetic fields in the cooling channel, in order to characterise the ionization cooling equation [3]. The experiment also seeks to measure transverse normalized emittance reduction in a number of lattice configurations. Measurement of scattering distributions Though multiple Coulomb scattering is a well understood phenomenon, results from MuScat [4] indicate that the effect in low Z materials is not well modelled in simulations such as GEANT4 [5] and therefore it is essential for MICE to validate the scattering model. Bayesian deconvolution has been applied to data collected at three different momenta (172 MeV/c, 200 MeV/c and 240 MeV/c) with