Douglas BrymanUniversity of British Columbia

Seeking New Physics with Rare DecaysEarly Adventures at TRIUMF and Future Prospects

JMP Retirement Symposium 2012

04/22/23 JMP 2

Standard Model : A great story … but definitely not the whole story…

• Cosmological issues: inflation, dark matter, dark energy, matter anti-matter asymmetry…

• Theoretical issues: gravity, neutrino mass, flavor problem, hierarchy problem, divergences .…

+ Higgs

3

COSMOLOGICAL

EVOLUTION, BBN

LEPTOGENESIS?

Rare Decays and Symmetry Violations

LHC: TeV Energy Scale

New Physics

Higher Mass Higher Mass Scales?Scales?

Rare DecaysNeutrino oscillations; CP-/T-violation, edm's...

, ,K, B...

Direct production of new particles

Indirect indication of new particles and effects

4

Light Particle Rare Decay Experiments

Exotic SearchesNew physics if seen; SM effects are negligible.

BSM Physics

New physics if deviations from well-calculated SM predictions occur.

L Ve F

( )( )

Universality K eK

10-10: 7 events

<7.8 10-13

<2.4 10-12

10-4: 4x105 events

0 0 violationL

K

K CP

LFN Ve N

Early TRIUMF Experiments – Still being pursued today!

<2.6 10-8

1977TRIUMF

1986

1983,1994

1983 2004

State of the Art

Jean-Michel and Renee were important contributors to many experiments.

Seeking Answers with Rare Decays

Cartoon from Jewish Daily Forward (1920’s)

Not exactly the mainstream

6

Lepton Flavor Violation

e

e e

W

e0

e

SM

604

4B 10R( )W

e mm

SUSYBR( )e

4

5 2

SUS2

Y

2 100 GeV10 tanemmm

≈ 10-13

• Observation means new physics.• Some SUSY models predict BR(→ e) near the

experimental limit ~10-12.

SM SUSY

H4H

1Sensitivity to new physics ~ with M ~ 1 100 TeVM

ee Muon Decay

e

e

04/22/23 7

History of Some Rare Decay ExperimentsLepton Flavor Violation

90% CL

Future: Many newexperiments coming.

From Marciano, Mori, Roney 2010

D.B. Thesis

TRIUMF TPC… (1987)

TRIUMF µ->eγ1977TINA+MINA

Hincks, Pontecorvo

J.M. Poutissou, D. Measday et al.

e (1974)

04/22/23 8

• 107 – 108 /sec, 100% duty factor• LXe for efficient detection• Solenoidal magnetic spectrometer

MEG Experiment at PSI

S. Ritt

Goal B<1.310-13 (0.01 x prev. exp) e

Current result (2009-2010) data B <2.410-12 (90% c.l.)

JPARC: DeeMee Aoki et al.

04/22/23 Doug Bryman JMP Symposium 9

100 /MeV c

14at <10 N e N

10

16at 10 N e N

BNL MECO 2e Conversion at Fermilab

Mu E

at JPARCKuno et al.COMET

• Singles experiment mitigates high rates.• Background (decay-in-orbit) known and calculable.• High resolution detector feasible.• Possible improvement x 104

Lobashov (1980): Solenoid Pion Collector; flux x 1000.

Proposals:

Lepton Universality & e , , have identical electroweak gauge

interactions: differ only in mass and coupliStandard M

ng to Higgodel:

s on.

bose

,e

S=0

e J=0

e ...Unless new physics does not respect universality.g =g

Universality Testse

410 Helicity Suppression

-Leptoquarks-Excited gauge bosons-Compositeness-SU(2)xSU(2)xSU(2)xU(1)-Lepton Flavor Violation-Extra dimensions…-Heavy neutrinos

R-parity violating SUSYOthers

Marciano…

Ramsey-Musolf…

2H

1New Physics e.g. pseudoscalars in ~M

?e

exp/0.1 % measurement of R 1000 TeVe H

M

H e

Non-standard Higgs couplings

04/22/23 JMP Symposium 13

TRIUMF 1

PSI 1TRIUMF 2

PIENU (TRIUMF 3) PEN (PSI 2)Goals (±0.05%)

4/R =1.2353 1 10 (±0.008%) th

e x

W. Marciano V. Cirigliano (2007)

Theory (±0.008%)

(±0.33%)

Branching Ratioe

Experiments

14

e+

Precision goal: <0.05%

• Large solid angle (x10)Large solid angle (x10)– More statistics – Lower energy dependent acceptance difference– Detect shower leakage (CsI) for low energy tail – measurement (biggest systematics)

• Silicon Strips & WC TrackingSilicon Strips & WC Tracking– Much improved tracking– Detect Decay-In-Flight for tail correction

• High resolution calorimeterHigh resolution calorimeter– BINA resolution 2 times better than TINA

• Use of 500 MHz fast digitizersUse of 500 MHz fast digitizers– Good separation between ->eν and ->µ->e

beam

50 cm

04/22/23 JMP Symposium 15

04/22/23 16

Photonuclear Effects in NaI(Tl) Detectors

A positron beam was injected into the NaI(Tl)

Extra structure (bumps) were observed – simulation confirms that multiple neutron emission is responsible.

Simulations:With PhotonuclearSans Photonuclear

Data

04/22/23 17

Energy Spectrum

5Suppress 10 to reveal the NaI low energy taile

Current Estimate:Tail Fraction (2.03 0.28)%

PIENU Time DATA and Fits

Low Energy High Energy

Expected Error Budget:

04/22/23 19

Summary: Rare Decays

-e Conversion: DeeMee, COMET (JPARC), Mu2E (Fermilab)* Future experiments have great potential:

ORKA Project X (Fermila (Fermil bab): ) ; K

* , , and K decays continue to challenge the Standard Model * Current experiments have great sensit

MEG ( ), PIENU and PEN ( ,

NA6

ivity to possible new physics

2 ,

:e )PSI TRIUMF PSI

CERN JPA

e

K

30 0 KOTO & TREK( )LRC KK

For more than two decades Jean-Michel and Renee Poutissou made many important contributions to successful TRIUMF experiments searching for and measuring rare decay processes.