Muon Capture on the Deuteron – MuSun Experiment  + d  n + n +  + d  n + n + model-independent connection via EFT

Discussion Topics n Experiment n Astrophysics big picture How different/cleaner than hybrid EFT and tritium? Status, expectation L 1A What impact on neutrino physics n Few body, EFT big picture Connection the general EFT program Plans of USC group Status muon capture (  p,  d,  3 He) n L 1A extraction n Additional physics opportunities n Steps towards proposal after USC meeting

Experiment

MuCap Setup  e

3D tracking w/o material in fiducial volume Muons stop in active TPC target p -- Observed muon stopping distribution E e-e- 10 bar ultra-pure hydrogen, 1.16% LH kV/cm drift field ~5.4 kV on 3.5 mm anode half gap bakeable glass/ceramic materials MuCap

Kinetics in pure D 2 qd d q

Kinetics: Time Distributions  d(  )  d(  )   He  d(  )+  d(  )

Sensitivities Parameters ± 0.10  d ± 0.01 Small sensitivity to kinetics qd easy to measure small 3 He background

 CF ionisation chamber, PSI 1996 dd  → 3 He +  + n (3.27 MeV) → 3 H +  + p (4.03 MeV) → 3 H +  + p (4.03 MeV)

TPC optimization for MuSun recombination drift velocity for Am 

Sketch MuSun

Baseline design n sensitive vol. 10x10x(8-10) cm3 n HV 60 – 100 kV n 1x1 cm pads

solid angle ok

EoS

General layout of the cryogenic target

TPC layout 1 cm 2 pad X wires with induction ?

TPC layout Dear Colleagues, We propose the following parameters of the anode plate for our new IC. 1. The total width of the anode plate 10 cm, the length 14 cm. 2. The inner sensitive ( for muon stops) part of the plate are: the width is 8 cm, the length (along beam direction) is 10 cm. 3. The anode plate has a pad structure, TOTALLY 46 pads. 4. The inner part has 36 pads (6*6): the width every pad 1.33 cm, the length 1.7 cm. 5. The outer (anti coincidence) part has 10 pads: 6 pads(left and right) have the width 1 cm, the length 4.66 cm. 4 pads (forward and back) have the width 4 cm and length 2 cm. The proposed anode structure give the possibility to detect the track incoming muon with about 100% efficiency at (5-8)% of LH density in fiducial area 8*10 cm2. Also, the space resolution ( less 1cm ) is enough for reliable tracking of decay electrons. With best regards, Evgeny

Experimental details: T Bernhard: Looking at the vapor pressure curve for nitrogen (from Wutz-Adam-Walcher - Handbuch Vakuum Technik) given to be: T (K) (temperature) P (mbar) (corresponding vapor pressure) relative concentration RC with respect to 10 bar follows as RC K result therefore in a 1 ppb concentration of Nitrogen all other gases, but Neon Hydrogen and Helium, are even lower 27 K in 0.1 ppb nitrogen concentration. Given that the vacuum vapor pressure is also valid for a hydrogen/ deuterium environment. Should this be an argument to design the muSUN working temperature to be 29 K or even 27 K this does not make a big difference from the kinetics point of view and from the cooling requirements, but likely a large difference from the impurity level.

Systematics

Astrophysics big picture n How different/cleaner than hybrid EFT and tritium? n Status, expectation L 1A n What impact on neutrino physics

Quest for L 1A Precise experiment in 2N system needed

Few body, EFT big picture n Connection the general EFT program n Plans of USC group

Status muon capture  p  d  3 He

 +d Capture Theory Experiment  Q ~ 10 Hz

Muon Capture on the Deuteron Theory Experiment  - + d   + n + n  EFT (error N 3 LO) EFT* (tritium  -decay)

 + 3 He → 3 H +  + 3 He → 3 H + authors  stat (s -1 ) comment Congleton & Fearing1304IA Congleton & Truhlik1502 ± 32IA + MEC Ackerbauer et al ± He TPC Marcucci et al.1484 ± 8IA+MEC, T beta constraint

Additional Physics Few-body and Astrophysics  + 4 He capture and the hep reaction  d+d → 4 He +   d+ 3 He → He +  +  Spin-polarized dd fusion Form Factors pp  ortho-para conversion

Various Ideas: Weak Interactions recoil polarization should be included  p: H(n,F)  p: Laser  d: Av g a sensitivity Serebrov  g a ~0.7%

Asymmetry and  SR n Capture dd n n Decay Dzhelepov group atm, P  =7.2 ± 2.1 % depolarization rate  = (4 ± 2) 10 7  s -1 Kammel, Meleshik, 1990, depolarization in elastic collisions

Various ideas: Fusion hep: 3 He + p → 4 He + e + +  4 He → t + n +  Dalitz plot ? dd  → 4 He +  +  p wave at low energies n d 3 He  → 4 He+  +p Theoretical motivation should be clarified Can one extract the S factor, which precision needed ? sensitivity study based on MuCap data

L1A extraction

Physics Motivation

“Calibrating the Sun” via Muon Capture on the Deuteron  + d  n + n +  + d  n + n + Goal total  d capture rate to 1% precision Motivation first precise measurement of basic EW reaction in 2N system, benchmark measurement with 10x higher precision impact on fundamental astrophysics reactions (SNO, pp) comparison of modern high precision calculations high precision feasible by  Cap technique and careful optimization model-independent connection via EFT & L 1A “MuSun”

Theory SNPA – EFT (HBChPT,  EFT, hybrid) 1B NN description accurate 2B not well constrained by theory Axial Currents in 2N System n Reactions  + d  n + n + basic solar fusion reaction p + p  d + e + + key reactions for SNO + d  p + p + e - (CC) + d  p + n + (NC) … MEC EFT L 1A EFT: Class of axial current reactions related by single parameter L 1A Quest for L 1A Precision  +d experiment (PK, Chen) best determination of L 1A from 2N system theory: precise enough? reaction soft enough for L 1A ? Ando, Park, Kubodera, Myhrer (2002) Chen, Inoue, Ji, Li (2005) experiment: 1% precision possible ? MuCap technique   E n (MeV) E n (MeV) p (MeV/c) 10 MuSun

10/24/07

Summary physics motivation precision measurement of total  d 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. a nn information ? (needs study) systematic measurement of  d capture Dalitz Plot provides information on time-like axial two-body currents reduced rate  ’, accessible to  EFT complementary g P sensitivity, if MECs sufficiently under control (needs study) first measurement of  d capture asymmetry and hfs effects provides complementary g p info (needs study)

Old

Differential observables n n-n correlation at small q nn : a nn measurement, current exp: a nn =18.6 (4) fm d  /dE n n Dalitz Plot

Concept stage III  =175  =150  =155  =160  =165  =170  =145

Statistics  Q =400 s -1, while  S =710 s -1, 3 times more statistics needed If we measure statistical hfs mixture additional 9 times more statistics needed, i.e. total 27 times more than MuCap Precision measurement needs  >5%

Impurities Requirements 5x  of MuCap 5x higher transfer rate  dZ =  c Z dZ c Z 25x smaller than MuCap to have same  tr c Z smaller at 30 K Monitoring Continuous accumulation in CHUPS flow for GC But does that represent cold target conditions? check with H 2 fill direct observation with coinc X rays and recoil

Impurities ppm PSD

Plan 2008 Focus on key issues for MuSun Experiment  Reconfigure TPC2 as ionisation chamber in summer 08  Reassamble ePC tracker in summer 08  Run 10 weeks before Christmas, Goals  Demonstrate IC operation with D 2 filling, excellent resolution  Achieve Full FADCs readout  Demonstrate impurity monitoring and calibrate for N 2, (H 2 O)  Measure d-N (O) transfer rate  Polarization  Initial capture measurement Fall 2009: Comissioning of full production set-up, First data run

Some Proposal Tasks

Matrix: Solar + Atmospheric