MuD project: m + d  n + n + n

MuD project: m + d  n + n + n Peter Kammel, UIUC Outline Physics MotivationExperimental Concept • fundamental EW 2-body reactions • high impact for fundamental astrophysics reactions • 10x precision improvement feasible by MuCap techniques

n d n W pn(MeV/c) 10 nm m- 20 20 En (MeV) En (MeV) 30 30 40 40 50 50 MEC>IA MEC>IA 60 60 70 70 80 80 9 0 9 0 1 00 1 00 FSI FSI QF QF En (MeV) pEFT Relevant Physics Pn= 0 MeV/c Ld • two mdhfs states: quartet  and doublet • overall nucleon FF dependence similar to mp, dLd=1%  dgP=6% • 2-N physics important (deuterium wavefunction, ann, …) • MEC’s significant • space-like (small qnn): dominantly D isobar currentEFT: L1A (isovector, axial) 4N vertex • time-like (large qnn): MEC 10x IA contribution, higher sensitivity to gp ?, (neutrino mass, historic) mD

MECEFT L1A pEFT: Class of axial current reactions related by single unknown parameter L1A • basic solar fusion reaction • p + p  d + e+ +  • key reactions for solar neutrino detection and supernova neutrino •  + d  p + p + e •  + d  p + n +  • short distance, axial two body currents, ab-inito pEFT(NNLO) vs. SNPA vs. EFT* gpND md capture close terrestrial analogue • soft enough ? • precision measurement possible ? p n d d p n W W e+ nm m- ne mD

L1A information From H. Robertson talk mHe ? Would be by far best constraint from basic 2-body system ! mD

m+d theory results total Ld (s-1) IA calculations Ando et al (2002): EFT* with tritium decay constraintestimate of uncertainties commentsensitivity to cut-off 1 s-1 no 3N uncertaintygP 1 assumes PCAC value higher order 1 L>0 2total ~1% ann ~3% ??, rad. corr. need calculations 2 body currents 6.5%, High qnn contribution negligible  1% experiment on Ld measures L1A to 15-20% Chen (private comm): pEFT, q < 10MeV/c, higher oder ?

m+d experiments challenges: md() + d md() + d ddm  n + m3He x3, because really statistical mix Ld (s-1) theory experiments

update m3He capture rate IA IA+MEC Marcucci 02 gpND constraint by tritium decay Ho,Fearing 01 Congleton,Truhlik 96Congleton, Fearing 93EPMCongleton, Fearing 93 theory time Ackerbauer 98 experiment Lst (s-1)

Differential observables • n-n correlation at small qnn: ann measurement, current exp: ann=18.9 (4) fm • dL/dEn • Lq/Ld~2.5% measurement • Asymmetry and mSR

Summary physics motivation • precision measurement oftotalmd capture rate to 1% provides • first precise measurement of charged-current reaction in 2N system • first precise 2N experimental information relevant for absolute solar neutrino cross sections and flux. • comparison of EFT/SNPA approach for space-like axial two-body current and 2N vs 3N constraints. • ann information ? (needs study) • systematic measurement of md capture Dalitz Plot provides • information ontime-like axial two-body currents, p+p+p puzzle • reduced rate L’, accessible to pEFT • complementary gP sensitivity, if MECs sufficiently under control (needs study) • first measurement of md capture asymmetry and hfs effects provides • complementary gp info (needs study)

1% precision experiment possible? • measurement of absolute rate 3 % (MuD 0) ? • Basic lifetime method, present TPC • measurement of absolute rate 1 % (MuD I) • Kinetics requires optimized target conditions 80K, 5% density, new TPC arrangement • mSR effects • isotopic purity much simpler • measure full DP if sufficient physics motivation (MuD II)Neutron detector array • Kinematics determined by angle and dt • liquid target? • Goals: • determine reduced rate L’ by subtracting Dalitz Plot (En>10MeV)with 5% prec. • gP, time-like MECs • <1% precision seems possible according to preliminary feasibility study ! md() 5% LD280 K md() m3He 20 En (MeV) En (MeV) L’~90% of intensity

kinetics

kinetics 5% LD280 K 1% LD2300 K md() md() md() md() m3He m3He Sensitivity to parameter y S(y)=DLd/Ld / Dy/y f=1%, T=300 systematic errors ~1%f=5%, T=80 corrections <3%, systematic errors <0.1%

=175 =170 =165 =160 =155 =150 =145 Exp. concept

MuD project: m + d  n + n + n