IKON7, Instrument clip session, September 2014, ESS Headquarters and Medicon Village, Lund, Sweden A cold neutron beamline for Particle ESS by Camille Theroine

Why study Particle Physics ?  Example of question: -What is the nature of the dark matter ? ….

Why study Particle Physics ?  Two complementary ways: -The energy frontier: based on measurements of particle interactions in collisions of highest possible energy, aiming to the production of new heavy elementary particles CERN).  Example of question: -What is the nature of the dark matter ? ….

Why study Particle Physics ?  Two complementary ways: -The energy frontier: based on measurements of particle interactions in collisions of highest possible energy, aiming to the production of new heavy elementary particles CERN). -The precision frontier: look carefully at low-energy processes that can be accurately predicted by the SM. The differences from expectations in such processes would prove the existence (and give information) on the form of new physics.  Example of question: -What is the nature of the dark matter ? ….

What the Universe is made of ? -Heavy elements: 0.03% - Neutrinos: 0.3% -Stars: 0.5% -Mainly Hydrogen/Helium Could explain why the expansion of the Universe is faster and faster

What the Universe is made of ? new particles Examples: Supersymmetry Left right symmetry New interactions Examples: Scalar interaction Tensor interaction Differences from expectations in the neutron decay -Heavy elements: 0.03% - Neutrinos: 0.3% -Stars: 0.5% -Mainly Hydrogen/Helium Could explain why the expansion of the Universe is faster and faster

Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions High precision frontier physics with a cold neutron ESS

Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB High precision frontier physics with a cold neutron ESS

Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Properties of the neutrons nEDM (beam) Neutron charge Properties of the neutrons nEDM (beam) Neutron charge Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB High precision frontier physics with a cold neutron ESS

Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Standard Model of particle physics (SM) Precision experiments Beyond SM New interactions Properties of the neutrons nEDM (beam) Neutron charge Properties of the neutrons nEDM (beam) Neutron charge Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB Neutron decay Correlations coefficients -> aSPECT, PERKEO III, PERC Neutron lifetime (beam) Bound beta decay  BoB High precision frontier physics with a cold neutron ESS Hadronic parity violation with neutrons Nucleon nucleon interaction  NPDγ Hadronic parity violation with neutrons Nucleon nucleon interaction  NPDγ

Pulse structure : eliminate or control systematic uncertainty. Advantages of long-pulsed spallation source

Pulse structure : eliminate or control systematic uncertainty. Wavelength info without statistics loss -Separation of neutron velocity dependent systematic effects  e.g : Neutron spin rotation in magnetic fields -Wavelength-resolved polarization for free  e.g : NPDγ Advantages of long-pulsed spallation source

Pulse structure : eliminate or control systematic uncertainty. Wavelength info without statistics loss -Separation of neutron velocity dependent systematic effects  e.g : Neutron spin rotation in magnetic fields -Wavelength-resolved polarization for free  e.g : NPDγ Spatial localisation of neutron pulse -Beam-related background -Pulsed measurements to investigate spatial dependence of spectrometer response  e.g : PERKEO III, PERC Advantages of long-pulsed spallation source

Pulse structure : eliminate or control systematic uncertainty. Wavelength info without statistics loss -Separation of neutron velocity dependent systematic effects  e.g : Neutron spin rotation in magnetic fields -Wavelength-resolved polarization for free  e.g : NPDγ Spatial localisation of neutron pulse -Beam-related background -Pulsed measurements to investigate spatial dependence of spectrometer response  e.g : PERKEO III, PERC Time localisation of neutron pulse -Increased signal/background ratio -Measurement of spectrometer background between pulses  aSPECT Advantages of long-pulsed spallation source

Note: This is distance to “detector ” Maximum time-averaged flux with wavelength information Requirements for the cold neutron beamline (1)

1.8…8Å without frame overlap → 45 m Note: This is distance to “detector ” Maximum time-averaged flux with wavelength information Requirements for the cold neutron beamline (1)

1.8…8Å without frame overlap → 45 m 1.8…8Å without prompt pulse → 35 m Note: This is distance to “detector ” Maximum time-averaged flux with wavelength information Requirements for the cold neutron beamline (1)

Distance  Resolution PERCaSPECT nEDM NPDγ good resolution : no need need good resolution Requirements for the cold neutron beamline (2) Reasonable wavelength resolution (instantaneous bandwidth) For 35 m beamline: Wavelength resolution ~ 0.3 Å Distance between beamlines (5°): 3 m → need slim neighbours or double port Fast neutron background : curved guide Courtesy T. Soldner

ILL Guide length Flux Requirements for the cold neutron beamline (3) Distance Well-pronounced pulse structure

ILL Guide length Flux Requirements for the cold neutron beamline (3) Distance Well-pronounced pulse structure

Summary Strong european groups and projects for cold neutron decay studies.

Summary Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Strong european groups and projects for cold neutron decay studies.

Summary Cold beam line can profit from pulse structure Wavelength information for free Time localisation of pulse Spatial localisation of pulse  Eliminate or control systematic uncertainty Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Strong european groups and projects for cold neutron decay studies.

Summary Cold beam line can profit from pulse structure Wavelength information for free Time localisation of pulse Spatial localisation of pulse  Eliminate or control systematic uncertainty Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Requirements for the beam line Maximum time-averaged flux with wavelength information Reasonable wavelength resolution Well-pronounced pulse structure Strong european groups and projects for cold neutron decay studies.

Summary Beam parallelising extraction for long experiments (PERC, PERKEO II) Cold beam line can profit from pulse structure Wavelength information for free Time localisation of pulse Spatial localisation of pulse  Eliminate or control systematic uncertainty Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Requirements for the beam line Maximum time-averaged flux with wavelength information Reasonable wavelength resolution Well-pronounced pulse structure Strong european groups and projects for cold neutron decay studies.

Summary Beam parallelising extraction for long experiments (PERC, PERKEO II) Cold beam line can profit from pulse structure Wavelength information for free Time localisation of pulse Spatial localisation of pulse  Eliminate or control systematic uncertainty Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Focusing option for high flux and large divergence experiments (aSPECT, npdγ) Requirements for the beam line Maximum time-averaged flux with wavelength information Reasonable wavelength resolution Well-pronounced pulse structure Strong european groups and projects for cold neutron decay studies.

Summary Beam parallelising extraction for long experiments (PERC, PERKEO II) Cold beam line can profit from pulse structure Wavelength information for free Time localisation of pulse Spatial localisation of pulse  Eliminate or control systematic uncertainty Large experimental programme PERC (guide) PERKEO II (low divergence) aSPECT (large diverg.) npd  (target) …  reference experiments for beam line design Focusing option for high flux and large divergence experiments (aSPECT, npdγ) Requirements for the beam line Maximum time-averaged flux with wavelength information Reasonable wavelength resolution Well-pronounced pulse structure Strong european groups and projects for cold neutron decay studies. Proposal for the cold neutron beam line for particle physics will be submitted in January 2015.

Thank you !

ESS *F. Piegsa, Phys. Rev. C 88 (2013) Could profit from the pulse structure of ESS: -Signal α 1/f -Systematics α f = Gains in term of systematic studies 50 m Systematic effects in EDM … -Variation of B field -Leakage currents from E field (produce heating) -VxE effects : main source of systematic error ( B=VxE : change precession frequency) The VxE effect can be separated from the EDM phase effect using the pulsed structure of a spallation source like the ESS Source-detectors 75 m Neutrons 6-10 Å ( m/s) Sensitivity: 5∙ ecm Different velocity dependence of signal and systematics – separation for free