New Projects at KEK Mistuaki Nozaki (KEK-IPNS)

New Programs CMB B-mode polarization –quick start by joining QUIET/Polar-BeaR –R&D for future space program LFV –strengthen contribution to –data analysis in addition to hardware contribution –feasibility study of mu-e Others under discussion –Laser acceleration and physics with strong EM field –Physics with UCN –Physics with muons, e.g. g-2

Experimental Cosmology Program at KEK Precision Measurements of Cosmic Microwave Background (CMB) Polarization Precision Measurements of Cosmic Microwave Background (CMB) Polarization : B-mode polarization (“curl component”) Objective: B-mode polarization (“curl component”) : Inflation, primordial gravitational wave, quantum gravity Science: Inflation, primordial gravitational wave, quantum gravity : Projects: QUIET phase Iphase II QUIET+PolarBeaR Combined analysis Superconducting detector R&D (w/ RIKEN etc.) Satellite WG (w/ JAXA etc.) Preparation for a (small) satellite Launch before 2020 (Actual plans will depend on many factors) Plan

4 QUIET: overview Ground-based experiment in Atacama (Chile) Ground-based experiment in Atacama (Chile) Detector: HEMT Detector: HEMT Innovative “polarimeters on a chip” (JPL) Innovative “polarimeters on a chip” (JPL) Phase I commissioning: summer 2008 Phase I commissioning: summer GHz “W-band”: 91 elements 90 GHz “W-band”: 91 elements 40 GHz “Q-band”: 19 elements 40 GHz “Q-band”: 19 elements Phase II: ~1000 elements Phase II: ~1000 elements Primary Mirror 2nd Mirror Mount Focal Plane (Receiver) Electronics Box Platelet Array Mirrors & Support Structure

QUIET: prospects Expect to observe B-mode originating from plausible inflation scenarios

6 Expected sensitivities of future experiments Point 2: Important to measure low l (down to reionization bump) Key to the success: Foreground understanding (astronomical info crucial) ~20° Point 1: Impressive sensitivities from the ground Magic patches with small foreground (OK for l~100) More robust against atmospheric fluctuation than ~2°~0.2°

Small Satellite Basic concepts: Basic concepts: Focus on low l (l < 200) Focus on low l (l < 200) As light as possible As light as possible Multi-color bolometers (~1000 ch) Multi-color bolometers (~1000 ch) 100 mK 100 mK Small satellite missions at JAXA Small satellite missions at JAXA New initiative New initiative Payload < 400kg Payload < 400kg 1 launch/~2years from ~ launch/~2years from ~2013 Alternative: super-pressure balloon (JAXA) Alternative: super-pressure balloon (JAXA) Allow ~100day flights in the future Allow ~100day flights in the future Willing to have international activities Willing to have international activities Cf. B-pol study (Europe) Cryostat109kg Focal plane 74kg Warm electronics 65kg …..

KEK Detector Technology Project Clean Rooms Experimental hall in which the clean rooms will be built. Sputtering/Etching machines (~Jul.08 from RIKEN) Image of a clean room Room A: 15m x 10m (Class 10000) Room B: 15m x 10m (Class ) Yellow room: 5m x 6m (Class 1000, in Room A) Mask aligner (Mar.08) 0.3K cryostat (Mar.08) A B Y

Superconducting detector R&D for the future (2007 ~ ) Part of activities inside the KEK Detector Technology Project CMB as an important application, but not exclusive Current target: Pure Al STJ sensors for ultra-fast/large-dynamic range mm-wave camera Joint R&D on TES with UC Berkeley/LBNL proposed Joint effort with RIKEN, TIT, Tohoku New !

List of collaborators KEK QUIET group KEK QUIET group Masashi Hazumi, Takeo Higuchi, Osamu Tajima Masashi Hazumi, Takeo Higuchi, Osamu Tajima Superconducting detector R&D Superconducting detector R&D Masashi Hazumi, Takeo Higuchi, Shigeru Ishimoto, Takahiro Morishima, Hirohiko Shimizu, Kazutaka Sumisawa, Osamu Tajima, Yutaka Ushiroda, Mitsuhiro Yoshida (KEK) Masashi Hazumi, Takeo Higuchi, Shigeru Ishimoto, Takahiro Morishima, Hirohiko Shimizu, Kazutaka Sumisawa, Osamu Tajima, Yutaka Ushiroda, Mitsuhiro Yoshida (KEK) Seiichiro Ariyoshi, Chiko Otani, Hiromi Sato (RIKEN) Seiichiro Ariyoshi, Chiko Otani, Hiromi Sato (RIKEN) Hirokazu Ishino (TIT) Hirokazu Ishino (TIT) Izumi Ota, Makoto Hattori (Tohoku) Izumi Ota, Makoto Hattori (Tohoku) (plus a new assistant professor and a grad. student from ~May, and hope more to join)

LFV in charged leptons

MEG at PSI Sensitivity ~ by employing –World-most intense DC muon beam at PSI –Liquid Xe photon detector –Innovative positron tracking system (COBRA system) Start full physics data acquisition in 2008 Runs for 3 years

MEG Detector Upgrade Improve detector resolution and background rejection capability Finer granularity on the inner (entrance) face –APD –1 inch PMT Prospects –Better event reconstruction shallow event Pile-up –Incident angle measurement K. Ni et al NIM A551 (2005) Hamamatsu R inch PMT

If we succeed to observe enough number of events… –Possible to investigate “inside the loop” Produced muon itself is polarized   e  Angular Distribution  eReR   eLeL  Kuno and Okada, PRL 77(1996)434   e A L ? A R ? ??    SS S ~100% polarized

Mu-e conversion Complementary experiment to MEG –At least at ~  Br(   e  ) –If larger, different process must contribute Need intense muon beam –High power proton machine –Pulsed beam structure to suppress background Possible bunch scheme at J-PARC 1.07  s 0.07  s measure 0.7  s Extinction <10 -9 ee  -e conversion

New Initiatives at KEK Energy frontier –LHC –ILC R&D Luminosity/intensity/precision frontier –Lepton sector T2K MEG --> mu-e conversion –Quark sector (Super-) KEKB Rare K –Others CMB polarization physics with neutrons, physics with strong EM field Detector R&D