1 Peter Kammel Muon Capture and Basic Solar Neutrino Reactions The New MuSun Experiment Muon Capture and Basic Solar Neutrino Reactions The New MuSun Experiment UIUC, April 23, 08

2 Collaboration V.A. Andreev, V.A. Ganzha, P.A. Kravtsov, A.G. Krivshich, E.M. Maev, O.E. Maev, G.E. Petrov, G.N. Schapkin, G.G. Semenchuk, M.A. Soroka, A.A. Vasilyev, A.A. Vorobyov, M.E. Vznuzdaev Petersburg Nuclear Physics Institute, Gatchina , Russia D.W. Hertzog, P. Kammel, B. Kiburg, S. Knaack, F. Mulhauser, P. Winter University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA M. Hildebrandt, B. Lauss, C. Petitjean Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland T. Gorringe, V. Tishchenko University of Kentucky, Lexington, KY 40506, USA R.M. Carey, K.R. Lynch Boston University, Boston, MA 02215, USA R. Prieels Universite Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium F.E. Gray Regis University, Denver, CO 80221, USA A. Gardestig, K. Kubodera, F. Myhrer University of South Carolina, Columbia, SC 29208, USA Combined forces MuCap & MuLan

3 Goal and Motivation   + d  + n + n Rate  d from  d(  ) atom Measure  d to < 1.5 % Measure  d to < 1.5 % n Simplest weak interaction process in a nucleus allowing for precise theory & experiment  nucleon FF (g P ) from MuCap  model-independent calculations with effective field theory n Close relation to neutrino/astrophysics  model-independent connection  +d to pp fusion and +d reaction n Broader Impact on modern nuclear physics  EFT relates  +d to strong processes like  +d   + n +n, a nn

4  + d  + n + n Theory Axial current reaction Gamow-Teller 3 S 1  1 S 0 n one-body currents well defined FF, deuteron wavefunction, a nn n two-body currents not well constrained by theory (short distance physics) n Methods Potential model + MEC Effective field theories (EFT) pion less (q/m  ) ChPT (q/   ) hybrid EFT (EFT operators, Pot.Model wavefct) MEC L 1A, d R EFT    Low Energy Constants

5  + d Experiment n Experimental Challenges n Dalitz Plot Intensity at low E nn ChPT covers most of DP  EFT only p > 90 MeV/c  → e   = s -1  d q, d → n+n+ q ~ 10 s -1,  d = 400 s -1  d(  ) + d→  d(  ) + d dd  → 3 He + n +  rates ~    d  

6 Precise Experiment Needed Potential Model + MEC pionless, needs L 1A hybrid EFT consistent ChPT Determine L 1A from clean system Ramnifications for -astro physics Quantify consistency of hybrid approach

7 n Basic solar fusion reaction p + p  d + e + + n Key reactions for Sudbury Neutrino Observatory e + d  p + p + e - (CC) x + d  p + n + x (NC) n Intense theoretical studies, scarce direct data EFT connection to  +d capture via LEC L 1A, n Muon capture soft enough to relate to solar reactions Connection to Neutrino/Astrophysics with L 1A ~ 6 fm 3

8 Quest for L 1A, d R Precision  +d experiment by far the best determination of L 1A in the theoretically clean 2-N system  “Calibrate the Sun”

9 Constraining Short Distance Nuclear Physics n g a axial current coupling to single-nucleon system n axial current coupling to two-nucleon system Connection to N-  physics analogous to Goldberger-Treiman relation 1N sector n Applications contribution to chiral 3N force from term determination reduces a nn uncertainty from theory  + d → n + n +  a nn  ± 0.27(exp) ± 0.30(th) fm future <0.05

10 Muon Capture, Big Picture  + p  + d  + 3 He { g P, g A, ChPT } { g P, g A, ChPT, L 1A, a nn }{ g P, g A, hybrid EFT, L 1A, 3N} Final MuCap 2-3x improvement Combined analysis

11 Experimental Strategy Two main conditions n Unambiguous physics interpretation Muon kinetics  optimization of D 2 conditions Very high precision  d to 1.2% (5 s -1 ) Statistics: several events Systematics !

12 Muon Kinetics Collisional processes density  dependent, e.g. hfs transition rate from q to d state =  qd density  normalized to LH 2 density complicated, can one extract fundamental weak parameters ? Muon-catalyzed Fusion q d qd  q d

13 Optimize Muon Kinetics n Time Distributions Sensitivities (  d  1%, x  2  x )  d(  )  d(  )   He dd MuCapMuSun 30 K !

14 Use Basic MuCap Technique n Lifetime method  →e decays measure   to 10ppm,  d = 1/   - 1/    to 1%  n Unambiguous interpretation at optimized target conditions n Ultra-pure gas system and purity monitoring at 1 ppb level Clean  stop definition in active target (cryo-TPC) n 3 times higher rate with Muon-On-Request (MuLan) log(counts) t e -t  μ+μ+ μ –      d reduces lifetime by  → e MuCap TPC top TPC side

15 Experiment Overview Experiment Overview  PC  SC ePC2 ePC1 eSC Cryo-TPC e 

16 Observables n Observables in MuSun experiment decay electrons main observable fusion and capture essential as kinetics and background monitors n Experience from MCF experiments  N capture

17 Cryo-TPC Design Criteria n Recombination n Drift Velocity n Equation of State n Specs

18 Cryo-TPC Design

19 Technical Design Cryo-System Vibration free cooling Continuous cleaning

20 Detectors and DAQ n Cryo-TPC special n Other detectors/infrastructure from MuCap  detectors as impurity monitor n DAQ from MuCap/MuLan n new: full analog TPC readout (complicated energy spectrum) 10x10 pads two 8-bit waveform digitizer channels per pad (50 MHz) 15 MB/s (4 MHz/s) before lossless compression 2006 BU digitizer

21 Statistics + Systematics  d (Hz) -- Statistics3.4 Systematics3.3 ++ from MuLan0.455 total  d uncertainty 4.8 Hz 1.2 %  d 10.5 ppm  1.8  events

22 Pad Optimization in Progress n Muon stop parameters Fake stops by  +p scattering n Fusion interference GEANT 10x10 pad MuCap TPC GEANT

23 Gas Purity n Circulating Hydrogen Ultrahigh Purification System (CHUPS) US CRDF 2002, 2005 n New: cryo-TPC cryo filter before TPC continuous getter in gas flow for gas chromatography n Particle detection in TPC much harder – fusion for MuSun –  signal 1 MeV excellent TPC resolution full analog readout tags – p after capture – X-ray protium measurement Rare impurity capture:  d + Z  d +  Z  (Z-1)* + MuCap achieved: ~ 10 ppb purity and 0.1 ppb purity monitoring MuSun needs: ~ 1 ppb purity or 0.5 ppb purity monitoring (Z-1)* +

24 Impurity detection n Capture recoil keV  (MuSun) =    (MuCap) Separate  N signal with Excellent energy resolution (30keV) Additional tag TPC signal topology Coincident X-ray, neutron  N capture, c N = 41 ppb p

25 Measuring Program n Stage 1 – 300 K TPC Rebuild (spare) MuCap TPC as ionization chamber Energy resolution Identification and separation of fusion recoils Full analog readout Measure  d →  Z transfer rate Optimize  N capture monitor with dedicated setup n Stage 2 – Cryo-TPC ? 6 Ready Fall 08 Ready Fall runs in total (prep. and data taking) 4 years

26 Responsibilities & Budget n Budget estimates Total new equipment 350k CHF Annual running costs100k CHF Heavily based on larger investments made for MuCap/MuLan n UIUC specific responsibilities Electron tracker (as in the past) Cryo-TPC together with PNPI: UHV pad plane and readout, low noise (TPC set-up at Illinois) Design optimization, track reconstruction, data analysis Exciting program already this summer: new undergrads, grad student

27 Organization

28 Project Schedule

29 Budget Details responsible institutionstotal equipment SystemPNPIUIUCPSIUKYBUUCLRUkCHF Detectors TPC Cryo system Gas & purification sys Electronics DAQ + computers total very preliminary

30 Solar n Sun Facts n Solar radius = 695,990 km = 109 Earth radii n Solar mass = kg = 333,000 Earth masses n Solar luminosity (energy output of the Sun) = erg/s n Surface temperature = 5770 K = 9,930º F n Surface density = g/cm3 = Air density n Surface composition = 70% H, 28% He, 2% (C, N, O,...) by mass n Central temperature = 15,600,000 K = 28,000,000º F n Central density = 150 g/cm3 = 8 × Gold density n Central composition = 35% H, 63% He, 2% (C, N, O,...) by mass n Solar age = yr

31 pp cycle

32 Bahcall & Pena-Garay 2004 n v fluxes from experiments + Luminosity constraint n Relevance of 7 Be exp. n Relevance of pp experiment SSM correct at 1%,  Luminosity (steady state, other energy generation?) MSW-vacuum transition Improvement  12

33 SNO assumes 1.1% uncertainty in  ( +d) but Truhlik, Vogel et al. estimate 2-3% model dependence n SSM assumes 0.4% uncertainty in pp S-factor Impact for both solar and physics should be updated e.g. SNO III:  (CC) from 6.3% to 4.0%  +d capture: calibration of fundamental reactions based on first principles Impact for Solar  and Physics A. B. Balantekin and H. Yuksel completely rests on hybrid EFT & 3-N

34 Solar updates n Borexino 2008 n Kamland 2008

35 Technology

36 CHUPS n c N, c O < 5 ppb, c H2O ~ 8-30 ppb n correction based on observed capture yield

37 CHUPS

38 n Results Directly from data c d = 1.49 ± 0.12 ppm AMS (2006) c d = 1.44 ± 0.15 ppm n On-site isotopic purifier 2006 (PNPI, CRDF)  p + d   d + p (134 eV)  large diffusion range of  d n < 1 ppm isotopic purity required MuCap Unique Capabilities:  p,  d diffusion n Diagnostic: vs.  -e vertex cut AMS, ETH Zurich e-e- e-e- pp p dp d or to wall  -e impact par cut World Record c d < 0.1 ppm

39 Spares

40 Geant

41 CAD PNPI

42 CAD UIUC

43 Varia fusion capture

44

45 Milled cylinder