MuD project: m d n n n

1
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

2
Relevant Physics
Pn 0 MeV/c
Ld

• two md hfs states quartet ?? and doublet ??
• overall nucleon FF dependence similar to
  mp, dLd1 ? dgP6
• 2-N physics important (deuterium
  wavefunction, ann, )
• MECs significant
• space-like (small qnn) dominantly D
  isobar current EFT L1A (isovector, axial)
  4N vertex
• time-like (large qnn) MEC 10x IA
  contribution, higher sensitivity to gp ?,
  (neutrino mass, historic)

mD
3
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
4
L1A information
From H. Robertson talk
mHe ?
Would be by far best constraint from basic 2-body
system !
mD
5
md theory results
total
Ld (s-1)
IA
calculations
Ando et al (2002) EFT with tritium decay
constraint estimate of uncertainties comment se
nsitivity to cut-off 1 s-1 no 3N
uncertainty gP 1 assumes PCAC value higher
order 1 Lgt0 2 total 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 lt 10MeV/c, higher
oder ?
6
md experiments
challenges md (??) d ?md (??) d ddm
? n m3He
x3, because really statistical mix
Ld (s-1)
theory
experiments
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update m3He capture rate
IA
IAMEC
Marcucci 02 gpND constraint by tritium
decay Ho,Fearing 01 Congleton,Truhlik
96Congleton, Fearing 93EPM Congleton,
Fearing 93
theory
time
experiment
Ackerbauer 98
Lst (s-1)
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Differential observables

• n-n correlation at small qnn ann measurement,
  current exp ann18.9 (4) fm

• dL/dEn

• Lq/Ld2.5 measurement

• Asymmetry and mSR

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Summary physics motivation

• precision measurement of total md 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 on time-like axial two-body
  currents, ppp 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)

10
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 (Engt10MeV) with 5 prec.
• gP, time-like MECs
• lt1 precision seems possible according to
  preliminary feasibility study !

md(??)
5 LD280 K
md(??)
m3He
20
En (MeV)
En (MeV)
L90 of intensity
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kinetics
12
kinetics
5 LD280 K
1 LD2300 K
md(??)
md(??)
md(??)
md(??)
m3He
m3He
Sensitivity to parameter y S(y)DLd/Ld / Dy/y
f1, T300 systematic errors 1f5, T80
corrections lt3, systematic errors lt0.1
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Exp. concept
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Comments on L1A relevance
pEFT
pEFT
SNPA
EFT
15
see Butler talk
Something interesting at NLO

• m-dependent!
• A two-body counterterm appears

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Orland
D20 (30) Tons
H20 (1500) Tons
NatFe (13.5 Tons)
NatPb(50 Tons)
Intrinsic neutrino properties and SM
physics Calibrating the Sun n d Strangeness
Form Factors n 16O Supernova
Thermometry n 16O Supernova Explosion
Mechanism n natFe Calibrating Supernova
Detectors n 16O n d
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nd
exp Bugey 1998 nd ? npn 6.08(77)
10-45 cm2 enn 9.83(204) 10-45 cm2
theory SNPA Ying, Haxton, Henley / Tatara,
Koyama, Kubodera
5-10 difference ChPT
NLO Butler, Chen (2000) pEFT
NNLO Butler, Chen, Kong (2001)
6.3 fm3
1.0 fm3
one unknown low energy constant L1A for 4 nucleon
axial counterterm, about ?5 contribution,
universal for nd reactions ...