A Trek to TREK*

Hampton University & Jefferson Lab, Virginia, USA

2010 Fall Meeting of the APS Division of Nuclear Physics, Nov. 2-6, 2010, Santa Fe, New Mexico

Michael Kohl <kohlm@jlab.org>

* Supported by DOE Early Career Award DE-SC0003884 and partially by NSF grant PHY-0855473

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Hadron Facility at J-PARC

TREK Program

Search for Time Reversal Symmetry Violation

Test of Lepton Universality

Search for Heavy Neutrinos

TREK Apparatus

Status & Schedule

Outline

Lower intensity

J-PARC Facility(KEK/JAEA ）

Bird’s eye photo in January of 2008

South to North

Neutrino Beams　 (to Kamioka)

JFY2009 Beams

50 GeV Synchrotron

Hadron Exp. Facility

Materials and Life Experimental

Facility

JFY2008 Beams

3 GeV Synchrotron

CY2007 Beams

Linac

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Beam Dump

T1 target

K1.8

K1.8BR

K1.1S-type

KL

K0.8C-type

30~50 GeV primary beam

Productiontarget (T1)

Hadron Experimental Hall

TREK: ~9 μA protons (270 kW) @ 30 GeV, flux ~2 x 106 K+/s, π/K ratio < 1

K1.1BR completed in summer 2010 using the supplementary budget of FY09 Commissioned in Oct. 2010 by TREK collaboration

- ESS Length of 2.0 m to be increased to 2.5 m- Length Q8-FF of 3.3 m to be reduced to 1.5 m (remove iron wall)

K0.8 Beam Line Installation

K1.1-BR

Proton beam

Q1, Q2

D2

Q3, Q4D1T1

ESS

Q5, Q6

D3

• FF

Q7 Q8

MS

IFX, IFY

SX1

SX2

HFOC

SX1

E06 (TREK) “ Measurement of T-violating transverse muon polarization (PT) in K+→ decays “ Stage-1, 270 kW

P36 (LFU)“ Measurement of (K+ →e+)/ (K+ →) and search for heavy sterile neutrinos” Proposal to PAC10,11; 30 kW

Planned Experiments

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TREK/E06 at J-PARC

http://trek.kek.jpOfficial website:

Time Reversal violation Experiment with Kaons:

Search for New Physics beyond the Standard Model by Measurement of T-violating

Transverse Muon Polarization in K+ μ+π0 νμ Decays

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CANADAUniversity of Saskatchewan Department of Physics and EngineeringUniversity of British ColumbiaDepartment of Physics and AstronomyTRIUMFUniversite de MontrealLaboratoire de Physique NucleaireUniversity of ManitobaDepartment of Physics

USAMassachusetts Institute of Technology (MIT) Laboratory for Nuclear Science & Bates Linear Accelerator CenterUniversity of South CarolinaDepartment of Physics and AstronomyIowa State UniversityCollege of Liberal Arts & SciencesHampton UniversityDepartment of PhysicsJefferson Laboratory

RUSSIARussian Academy of Sciences (RAS)Institute for Nuclear Research (INR)

JAPANOsaka UniversityDepartment of PhysicsNational Defense AcademyDepartment of Applied PhysicsTohoku UniversityResearch Center for ELectron Photon Science (ELPH)High Energy Accel. Research Organzation (KEK) Institute of Particle and Nuclear StudiesInstitute of Material Structure ScienceAccelerator LaboratoryKyoto UniversityDepartment of PhysicsTokyo Institute of Technology (TiTech) Department of Physics

VIETNAMUniversity of Natural Sciences

TREK Collaboration

New collaborators are welcome!

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C, P, and T

Before 1956:All of nature’s laws invariant under• Charge conjugation• Parity• Time reversal

Right-handedantiparticle

Positron orAnti-neutrino

Electron orNeutrino

Left-handedparticle

1956-1964• Parity violated in beta decay• Combination C+P good symmetry• T good, CPT good

1964 until today• Parity violated in weak interaction• CP violated in neutral K and B weak decays• CPT good• All observed CP violation allowed within SM through flavor mixing• Matter/Antimatter asymmetry lacks explanation

Search for New Physics beyond the SM!

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KEK-E246:PT = - 0.0017 ± 0.0023(stat) ± 0.0011(sys) ( |PT | < 0.0050 : 90% C.L. )

● K+ ➙π0μ+νDecay at restT-odd correlation

PT≠0 ⇒ T violation(CPT theorem) CP violation⇒Sakurai 1957

Transverse Muon Polarization

M. Abe et al., PRL83 (1999) 4253

M. Abe et al., PRL93 (2004) 131601

M. Abe et al., PRD72 (2006) 072005

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Model K+ 0+ K+ +

■ Standard Model <10-7 <10-7

■ Final State Interactions <10-5 <10-3

■ Multi-Higgs 10-3 10-3

PT (K+ 0+) 3 PT (K+ +)

■ SUSY with squarks mixing 10-3 10-3

PT (K+ 0+) - 3 PT (K+ +)

■ SUSY with R-parity breaking 4 x10-4 3 x10-4

■ Leptoquark model 10-2 5 x10-3

■ Left-Right symmetric model 0 < 7x10-3

New Physics: Model Predictions of PT

Use upgraded KEK--E246 detector

Active polarimeter

Fiber target

C0,C1 GEM

CsI(Tl) readout

K+→

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PT Measurement

PT is measured as the azimuthal asymmetry Ae+ of the + decay positrons

Highly precise SM values

High sensitivity to LFV beyond SM

Current experimental precision (KLOE, NA62)

Lepton universality in Kl2 and l2 decays

RKSM= ( 2.477±0.001) x 105

RSM= (12.352±0.001) x 105

RKLFV~RK

SM(1±0.013)

RK=(2.499±0.014)x105, 1.6σ dev., RK/RK=0.6% 0.3%

Improve precision to 0.1 – 0.2%, proposal to PAC10,11

e.g. MSSM with charged-Higgs SUSY-LFV

beam Target

n=1.05

Fresnel mirror

PID performance and detector efficiency will be controlled with Ke3 and Kμ3 data.

beam

e/ Identification

Momentum measurement of e+, μ+

TOF measurement between TOF1 and TOF2 e+ trigger by aerogel Cherenkov detector.(e+ from Ke2) ~1(+ from K) ~ 0.92=1/1.087 Estimated efficiency = 99.2 ± 0.2%

• Target: – Finer segmentation of TGT scintillating fibers

Readout: MPPC (SiPMT) or MA-PMT

• Particle ID:– Aerogel Cerenkov surrounding target

• Charged tracking:– Add new element C1 between CsI(Tl) and C2

– Add cylindrical GEM (C0) (remove aerogel)

• π0 (1&2 photon) detection:– New, faster readout of CsI(Tl): APD, MAPD– Operation of wave form analysis by FADC

• Muon polarimeter :– Active polarimeter with increased acceptance– New muon holding field magnet with a parallel field 15

Upgrade Proposal

LFV30 kW~2013

TREK270 kW>100 kW~2014

Light guide: WLS fiber in groove of SciFi

Bicron 692 WLS or Kuraray Y11 WLS

Readout: SiPMT (HPK MPPC)

Estimated hits in the photon sensor:

~ 7 x107 particles/year

3x3 mm2

489 fibers 75mm diameter

c.f. E246 Ring counters PSI FAST target

Cross section

Timing counters

One element

Active Fiber Target: Baseline Design

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70 – 150 cm

12 fiducial counters

•Improve the timing characteristics of CsI(Tl) by replacing PIN diode with APD

•Pulse shaping and pile-up analysis

One-module energy

One-module timing

too slow new requirement

•One-module test was done at Tohoku U. to check the higher-energy performance and high rate performance

APD Readout for CsI(Tl)

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TREK: Tracking Upgrade

Planar GEMs (C1)between CsI and C2 Cylindrical GEM (C0) in replacement of former C1

70 µm

140 µm

GEM technology:In collaboration with Hampton U., MIT, and Jefferson Lab

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Active Muon Polarimeter

Full angular acceptance for positrons – 10x more than in E-246 Determination of decay vertex – background-free measurement Measurement of e+ angle and approx. energy – higher analyzing power Improved field alignment – suppressed systematic error

Full-size prototype completed, tested at TRIUMF in Nov. 2009

μ+

e+

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TREK at J-PARC is gaining momentum “K1.1BR” secondary beamline has been commissioned Measure T-violating transverse muon

polarization in Kμ3 decays (~2014)- Large potential for discovery of New Physics- Upgrade of existing experimental setup of KEK/E-246

Measure Ke2/Kπ2 ratio to test lepton universality (~2013) Search for heavy neutrinos

- Use E-246 apparatus with partial upgrades

Summary

New collaborators are welcome!

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Backup Slides

PT≠0 ⇒ T violation(CPT theorem) CP violation⇒Sakurai 1957

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Transverse Muon Polarization

T-violation parameter

● K+ ➙π0μ+νDecay at restT-odd correlation

- -M ~ f+(q2)[2pk u (1-5)u + {(q2)-1}mu (1-5)u] (q2) = f-(q2) / f+(q2) m|p|PT = Im× mK E + |p| nn - m

2/mK

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Time Reversal Experiment with Kaons

TREK/E06: Upgrade of E246 setup

Reduce systematic error by factor ~>10- alignment with data- correction of systematics- advanced analysis scheme

Decrease statistical error by factor ~>20

- 20x higher K+ intensity at J-PARC - 10x larger polarimeter acceptance- >1.6x higher polarimeter sensitivity

New Proposal of PT (K3) at J-PARC

10-4

10-4

■ Small standard model contribution– Bigi and Sanda “CP violation” (2000)– Higher-order effect

– PT ~ 10-7

■ Small FSI spurious effects– Single photon contribution Zhitnitskii (1980)

PT < ~ 10-6

– Two photon contribution Efrosinin et al. PL B493 (2000) 293

PT ~ 4 x 10-6

SM

FSI (example)

W

many other diagrams

vertex radiative correction

Standard Model and FSI

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Typical models with scalar interactions allowing a sizable PT :

– Multi-Higgs doublet model– SUSY with R-parity violation or with large squark mixing

Kinematic factor

Generic four-fermion interaction Lagrangian analysis

Effective field theory with Wilson coefficients

Exotic Scalar Interactions

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Garisto and Kane, PRD 44 (1991) 2038

Required limits for n-EDM to constrain PT: E-246 / PT < 5 x 10-3: → dn < 1.3 x 10-26 e-cmTREK / PT < 3 x 10-4: → dn < 7.6 x 10-28 e-cm … with md ~ 6 MeV factor ~50 smaller, dn < 1.5 x 10-29 e-cm!

Current EDM limit dn < ~3 x 10-26 e-cmLimit of planned n-EDM experiment ~ 2 x 10-28 e-cm

Finite PT possible within current and future n-EDM limit

Neutron EDM vs PT in 3-Higgs-Doublet

≤

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TREK/E06 and E246

S

| ’|

|’ k ’k | (K+)

(KL)

TREK

E246

SUSY with R-Parity violation

E246 Result:PT = -0.0017

± 0.0023 (stat) ± 0.0011 (sys)

|PT | < 0.005: 90% C.L.

TREK sensitivity:

Δ|PT | < 10-4

E246

TREK goal

B→Xb→sNeu

tron E

DM

v2/v3 = mt / m

Three Higgs DoubletModel

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● c.f. dn , b→s Im(∝ *), (*)

Im(*) = -v22/v3

2 Im(*)

1

E246

TREK goal

B→Xb→s

Neutro

n EDM

●B→XandB→at Super-Bellecorresponds to PT < 3 x 10-4

c.f. TREK goal : PT ≤ 1 x 10-4v2/v3 = mt / m

PT is most stringent constraint for Im(*)!

___Higgs field v. e. v.

Three-Higgs Doublet Model

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Super potential : W = WSMMS + WRPV

Im = Iml + Im d

Relevant parameters and constraints

TREK

E246

| ’|

|’ k ’ k |

PT is a very stringent constraint for these parameters !

SUSY with R-Parity Violation

Wu and Ng, Phys. Letters B392, 93 (1997) Charged Higgs exchange Constraints on

Im S , Im P ∝ = tan(+Atcot)/mg~

× Im[V33H+* V32

DL * V31UR]/ MH

2

Im R tan∝ × Im[V33SKM* V33

UR * V32DR] / M2

If the flavor mixing is 0(1) the transversemuon polarization can be 0(10^{-3})

|Im| < 3.8 x 10-2

(E246 : 1997)

|Im| < 5 x 10-4

(TREK)

SUSY with Large Flavor Mixing

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Direct CP violation in K0 system :

Re(’/) = (1.66 ± 0.26)×10-3

　　　

If this effect is due to Higgs dynamics, it has to be due to charged Higgs exchange:

Because there is no I=1/2 suppression (~ 20) in the K+ system:

PT ~ R × 20 = 5 × 10-6 × 20 ~ 10-4

-- or larger if enhanced couplings to leptons!

(I. Bigi, CERN Flavor WS, 2007 )

_(K0→) - (K0→) _ (K0→) + (K0→)

= (5.04 ± 0.22) ×10-6 ≡ R

⇒

Direct CP Violation

In the framework of renormalizable extension of the SM, the MSM, 3 light singlet right-handed (sterile ) are introduced.

The MSM can explain oscillation

Light sterile play a role of Dark matter

Baryon asymmetry can be induced by leptogenesis through oscillation.

If the sterile is lighter than K+, K+ N could be observed.

PoS(KAON)047

Search for heavy sterile (N) in K+ +N

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fwd and bwd 0 /

PT directions

fwd -bwd -

Ncw - Nccw

Ae+ = Ncw + Nccw

Stopped beam method (K+ decay at rest) coverage of all 0 directions symmetric decay phase space

Double ratio measurement• small systematic errors

Longitudinal field method B // PT

J.A. Macdonald et al., NIM A506 (2003) 60

Features of E246

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Principle of GEM Detectors

• Copper layer-sandwiched kapton foil with chemically etched micro-hole pattern

gas amplification in the hole

• GEM = Gas Electron Multiplierintroduced by F. Sauli in mid 90’s, F. Sauli et al., NIMA 386 (1997) 531

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C0 Cylindrical GEM for TREK

300 mm14

0 m

m

160

mm

Vertex tracking near target, δ < 0.1 mm Very high rate capability 25 kHz/mm2 (COMPASS) Radiation-hardness 4 x1010 MIPs/mm2 (COMPASS)

TREK: Rates <250 Hz/mm2 (halo <5 Hz/mm2), total dose: 7 x107 particles

300 Gauss

Uniform fieldWell-aligned field

Muon Field Magnet for TREK

Control of muon spin motion

Shielding of stray field (by iron yoke)~0.3 G → < 0.1 G

Mechanical alignment of the 300G field → P ≈ 10-3

Further alignment using K3 data→ P ~ ≈ 10-4