Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Precise Measurement ofthe π+ → e+ν Branching Ratio
E. Frlež (for the PEN Collaboration)
Department of PhysicsUniversity of Virginia
New Trends in High Energy PhysicsYalta, Crimea, Sept. 27 - Oct. 4, 2008
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Outline
Physics MotivationPIBETA Experimental Programπ → eν: Theoretical Statusπ → eν: Experimental Status
Experimental ApparatusPEN DetectorCentral Detector RegionWaveform Digitizer
Data & AnalysisADC/TDC/DIG SpectraWaveform AnalysisANN Analysis
Summary & Future PlansPEN 2007-2009
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI Experiment R-05-01 (PEN) collaboration members:
L. P. Alonzi,a V. A. Baranov,c W. Bertl,b M. Bychkov,a
Yu.M. Bystritsky,c E. Frlež,a N.V. Khomutov,c
A.S. Korenchenko,c S.M. Korenchenko,c M. Korolija,f
T. Kozlowski,d N.P. Kravchuk,c N.A. Kuchinsky,c D. Mekterović,f
D. Mzhavia,c,e A. Palladino,a D. Počanić,a∗ P. Robmann,g
O.A. Rondon-Aramayo,a A.M. Rozhdestvensky,c T.Sakhelashvili,g V.V. Sidorkin,c U. Straumann,g I. Supek,f
Z. Tsamalaidze,e A. van der Schaaf,g∗ E.P. Velicheva,c andV.V. Volnykhc
aDept of Physics, Univ of Virginia, Charlottesville, VA 22904-4714, USAbPaul Scherrer Institut, CH-5232 Villigen PSI, SwitzerlandcJoint Institute for Nuclear Research, RU-141980 Dubna, RussiadInstitute for Nuclear Studies, PL-05-400 Swierk, PolandeIHEP, Tbilisi, State University, GUS-380086 Tbilisi, GeorgiafRudjer Bošković Institute, HR-10000 Zagreb, CroatiagPhysik Institut der Universität Zürich, CH-8057 Zürich, Switzerland
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN follows the PIBETA experiment
PIBETA program (precision checks of SM):
I π+ → π0e+νe—main goal◦ SM checks related to CKM unitarity
I π+ → e+νeγ(or e+e−)◦ FA/FV , π polarizability (χPT prediction)◦ tensor coupling besides V − A (?)
I µ+ → e+νeν̄µγ(or e+e−)◦ departures from V − A in Lweak
⇒ The PEN experiment:I π+ → e+νe◦ e-µ universality◦ pseudoscalar coupling besides V − A◦ ν-sector anomalies, Majoron searches, mh+, PS l-q’s, Vl-q’s, . . .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN follows the PIBETA experiment
PIBETA program (precision checks of SM):
I π+ → π0e+νe—main goal◦ SM checks related to CKM unitarity
I π+ → e+νeγ(or e+e−)◦ FA/FV , π polarizability (χPT prediction)◦ tensor coupling besides V − A (?)
I µ+ → e+νeν̄µγ(or e+e−)◦ departures from V − A in Lweak
⇒ The PEN experiment:I π+ → e+νe◦ e-µ universality◦ pseudoscalar coupling besides V − A◦ ν-sector anomalies, Majoron searches, mh+, PS l-q’s, Vl-q’s, . . .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN follows the PIBETA experiment
PIBETA program (precision checks of SM):
I π+ → π0e+νe—main goal◦ SM checks related to CKM unitarity
I π+ → e+νeγ(or e+e−)◦ FA/FV , π polarizability (χPT prediction)◦ tensor coupling besides V − A (?)
I µ+ → e+νeν̄µγ(or e+e−)◦ departures from V − A in Lweak
⇒ The PEN experiment:I π+ → e+νe◦ e-µ universality◦ pseudoscalar coupling besides V − A◦ ν-sector anomalies, Majoron searches, mh+, PS l-q’s, Vl-q’s, . . .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN follows the PIBETA experiment
PIBETA program (precision checks of SM):
I π+ → π0e+νe—main goal◦ SM checks related to CKM unitarity
I π+ → e+νeγ(or e+e−)◦ FA/FV , π polarizability (χPT prediction)◦ tensor coupling besides V − A (?)
I µ+ → e+νeν̄µγ(or e+e−)◦ departures from V − A in Lweak
⇒ The PEN experiment:I π+ → e+νe◦ e-µ universality◦ pseudoscalar coupling besides V − A◦ ν-sector anomalies, Majoron searches, mh+, PS l-q’s, Vl-q’s, . . .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN follows the PIBETA experiment
PIBETA program (precision checks of SM):
I π+ → π0e+νe—main goal◦ SM checks related to CKM unitarity
I π+ → e+νeγ(or e+e−)◦ FA/FV , π polarizability (χPT prediction)◦ tensor coupling besides V − A (?)
I µ+ → e+νeν̄µγ(or e+e−)◦ departures from V − A in Lweak
⇒ The PEN experiment:I π+ → e+νe◦ e-µ universality◦ pseudoscalar coupling besides V − A◦ ν-sector anomalies, Majoron searches, mh+, PS l-q’s, Vl-q’s, . . .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν decay: SM predictions; measurements
Modern theoretical calculations:
Bcalc =Γ(π → eν̄(γ))Γ(π → µν̄(γ))calc
=
1.2352 (5)× 10−4 Marciano and Sirlin, [PRL 71 (1993) 3629]1.2356 (1)× 10−4 Decker and Finkemeier, [NP B 438 (1995) 17]1.2352 (1)× 10−4 Cirigliano and Rosell, [PRL 99, 231801 (2007)]
Experiment, world average [current PDG]:
Γ(π → eν̄(γ))Γ(π → µν̄(γ))exp
= (1.230± 0.004)× 10−4
PEN goal:δBB' 5× 10−4 .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν decay: SM predictions; measurements
Modern theoretical calculations:
Bcalc =Γ(π → eν̄(γ))Γ(π → µν̄(γ))calc
=
1.2352 (5)× 10−4 Marciano and Sirlin, [PRL 71 (1993) 3629]1.2356 (1)× 10−4 Decker and Finkemeier, [NP B 438 (1995) 17]1.2352 (1)× 10−4 Cirigliano and Rosell, [PRL 99, 231801 (2007)]
Experiment, world average [current PDG]:
Γ(π → eν̄(γ))Γ(π → µν̄(γ))exp
= (1.230± 0.004)× 10−4
PEN goal:δBB' 5× 10−4 .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν decay: SM predictions; measurements
Modern theoretical calculations:
Bcalc =Γ(π → eν̄(γ))Γ(π → µν̄(γ))calc
=
1.2352 (5)× 10−4 Marciano and Sirlin, [PRL 71 (1993) 3629]1.2356 (1)× 10−4 Decker and Finkemeier, [NP B 438 (1995) 17]1.2352 (1)× 10−4 Cirigliano and Rosell, [PRL 99, 231801 (2007)]
Experiment, world average [current PDG]:
Γ(π → eν̄(γ))Γ(π → µν̄(γ))exp
= (1.230± 0.004)× 10−4
PEN goal:δBB' 5× 10−4 .
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:I charged Higgs in theories with richer Higgs sector than
SM,I R-parity violating SUSY; loop diagrams with certain SUSY
partner particles,I PS and V leptoquarks in various theories with dynamical
symmetry breaking,I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:
I charged Higgs in theories with richer Higgs sector thanSM,
I R-parity violating SUSY; loop diagrams with certain SUSYpartner particles,
I PS and V leptoquarks in various theories with dynamicalsymmetry breaking,
I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:I charged Higgs in theories with richer Higgs sector than
SM,
I R-parity violating SUSY; loop diagrams with certain SUSYpartner particles,
I PS and V leptoquarks in various theories with dynamicalsymmetry breaking,
I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:I charged Higgs in theories with richer Higgs sector than
SM,I R-parity violating SUSY; loop diagrams with certain SUSY
partner particles,
I PS and V leptoquarks in various theories with dynamicalsymmetry breaking,
I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:I charged Higgs in theories with richer Higgs sector than
SM,I R-parity violating SUSY; loop diagrams with certain SUSY
partner particles,I PS and V leptoquarks in various theories with dynamical
symmetry breaking,
I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Decay and the SM
Be/µ is given in SM to 10−4 accuracy; dominated by helicitysuppression (V − A). Deviations from this rate primarily causedby new pseudoscalar interactions (mass scale ΛeP):
∆Be/µ = 1−Bnewe/µBSMe/µ
∼√
2Gµ
m2πme(mu + md)
1Λ2eP
∼
(1TeVΛeP
2)× 103.
Thus (δB/B)exp = 10−4 probes ΛeP∼ 103 TeV! → Limits on:I charged Higgs in theories with richer Higgs sector than
SM,I R-parity violating SUSY; loop diagrams with certain SUSY
partner particles,I PS and V leptoquarks in various theories with dynamical
symmetry breaking,I non-zero mν and mixing; sterile ν’s; Majorans.
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Experimental Constraints on Lepton Non-UniversalityLepton coupling constants gl=e,µ,τ : gl = gl(1 + �l), ∆ij = �i − �j
Loinaz et al. PRD70 (2004).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Experimental Constraints on Lepton Non-UniversalityLepton coupling constants gl=e,µ,τ : gl = gl(1 + �l), ∆ij = �i − �j
Loinaz et al. PRD70 (2004).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam
• Segmented BGO calorimeter:132 crystals, φ 55 mm, l=300 mm
• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm
• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)
• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage
• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured
• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PSI π → eν Experiment: Czapek et al. 1993
• PSI cyclotron, 78 MeV/c π+ beam• Segmented BGO calorimeter:
132 crystals, φ 55 mm, l=300 mm• Good energy (1.7 %) and timing rms (1 ns)• large solid angle (∼ 4π) coverage• π+ → e+ν tail simulated, not measured• PRL93: (1.235± 0.004± 0.004) · 10−4
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam
• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm
• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution
• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage
• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured
• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4
• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006
◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008
◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
TRIUMF π → eν Program: D. Bryman et al. 1983 & 1993
• TRIUMF cyclotron, 83 MeV/c π+ beam• NaI(Tl) “TINA”: φ 460 mm, l=510 mm• Good energy and timing resolution• small (2.9 %) solid angle coverage• π+ → e+ν tail measured• PRD86: (1.218± 0.014) · 10−4• PLR93: (1.2265± 0.0034± 0.0044) · 10−4
• TRIUMF E1072 experiment proposed 2006◦ better tracking, larger solid angle (25 %)
Goal:δBB' 1× 10−3 .
◦ Engineering runs Aug.-Oct. 2008◦ Data taking 2009-10
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: 1998-2008
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: 1998-2008
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: 1998-2008
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: 1998-2008
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: Basic Subsystems
◦ stopped π+ beam◦ active tracking degrader◦ active target counter◦ 240-det. CsI(p) calo.◦ central tracking◦ digitized PMT signals◦ stable temp./humidity
AT
MWPC1
MWPC2
PV
AD
AC1
AC2BC
CsIpure
π+beam
10 cm
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: Basic Subsystems
◦ stopped π+ beam◦ active tracking degrader◦ active target counter◦ 240-det. CsI(p) calo.◦ central tracking◦ digitized PMT signals◦ stable temp./humidity
AT
MWPC1
MWPC2
PV
AD
AC1
AC2BC
CsIpure
π+beam
10 cm
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
The PIBETA/PEN Apparatus: Basic Subsystems
◦ stopped π+ beam◦ active tracking degrader◦ active target counter◦ 240-det. CsI(p) calo.◦ central tracking◦ digitized PMT signals◦ stable temp./humidity
AT
MWPC1
MWPC2
PV
AD
AC1
AC2BC
CsIpure
π+beam
10 cm
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Central detector region for the 2007/2008 run
ActiveDegrader
ActiveCollimator
Photomultiplier ModuleHamamatsu H2431-50
TargetCounter
12,5 mm
15,0 mm
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
4-wedge Tracking Active Degrader 2008
OverviewDeg2008Ver1.xxx
Universität Zürich
Allgemeintoleranz DIN 7168-f
Physik-Institut
Bearb.
der
POS.
Datum
ZEICH_Nr. ANZ. MATERIAL
MASSTAB:
FILE:
PROJEKT/TITEL:
BESCHREIBUNG
(±0.1)
Degrader 2008Overview
BLATT:
Robmann August 2002
PeterPro
x
y
x
z
y
x
y
z
π+Beam
Scintillation Properties BC-408
Light Output, %AnthraceneRise Time, nsDecay Time, nsPulse Width, FWHM, nsWavelength of Maximum Emission, nmBulk Light Attenuation Length, cm
640,92,1~2,5425380
Wrapping thickness: VM 2000 Foil+ Kapton
76 µm75 µm
top
bottom
left
right
5,00 mm1,50 mm
1,50 mm5,00 mm
1,50 mm5,00 mm
1,50 mm5,00 mm
ø 15,00 mm ø 12,00 mm
topHV cnannel S2
rightHV cnannel S1
bottomHV cnannel S3
leftHV cnannel S0
bottomHV cnannel S3
topHV cnannel S2
leftHV cnannel S0
rightHV cnannel S1
PEN Degrader 2008Version 1 Overview
Beam
◦ AD π+ + MWPC e+ Tracking =e+ pathlength in Target=suppresion of In-Flight Decays
◦ BC-408 Scintillator◦ 0.9 ns Rise Time◦ 2.1 ns Decay Time◦ 160 Phel/MeV◦ two x and two y Wedges◦ 3 cm Upstream of Target
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
4-wedge Tracking Active Degrader 2008
OverviewDeg2008Ver1.xxx
Universität Zürich
Allgemeintoleranz DIN 7168-f
Physik-Institut
Bearb.
der
POS.
Datum
ZEICH_Nr. ANZ. MATERIAL
MASSTAB:
FILE:
PROJEKT/TITEL:
BESCHREIBUNG
(±0.1)
Degrader 2008Overview
BLATT:
Robmann August 2002
PeterPro
x
y
x
z
y
x
y
z
π+Beam
Scintillation Properties BC-408
Light Output, %AnthraceneRise Time, nsDecay Time, nsPulse Width, FWHM, nsWavelength of Maximum Emission, nmBulk Light Attenuation Length, cm
640,92,1~2,5425380
Wrapping thickness: VM 2000 Foil+ Kapton
76 µm75 µm
top
bottom
left
right
5,00 mm1,50 mm
1,50 mm5,00 mm
1,50 mm5,00 mm
1,50 mm5,00 mm
ø 15,00 mm ø 12,00 mm
topHV cnannel S2
rightHV cnannel S1
bottomHV cnannel S3
leftHV cnannel S0
bottomHV cnannel S3
topHV cnannel S2
leftHV cnannel S0
rightHV cnannel S1
PEN Degrader 2008Version 1 Overview
Beam
◦ AD π+ + MWPC e+ Tracking =e+ pathlength in Target=suppresion of In-Flight Decays
◦ BC-408 Scintillator◦ 0.9 ns Rise Time◦ 2.1 ns Decay Time◦ 160 Phel/MeV◦ two x and two y Wedges◦ 3 cm Upstream of Target
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Acqiris Digitizer for Target Counters
◦ High-Speed 10-bit PXI/CompactPCI◦ 1 ch=8 G/s, 2 ch=4 G/s, 4 ch=2 G/s◦ Acquisition memory: 256-1024 kp◦ Complete pre- and post-triggering◦ Low 350 ns dead time◦ 400 MB/s PCI bus transfers data◦ High-res. TTI for accurate timing◦ Device driver for Windows XP
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Acqiris Digitizer for Target Counters
◦ High-Speed 10-bit PXI/CompactPCI◦ 1 ch=8 G/s, 2 ch=4 G/s, 4 ch=2 G/s◦ Acquisition memory: 256-1024 kp◦ Complete pre- and post-triggering◦ Low 350 ns dead time◦ 400 MB/s PCI bus transfers data◦ High-res. TTI for accurate timing◦ Device driver for Windows XP
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Statistical Uncertainties
Relative statistical uncertainty for Ne2 = (1 + �)Np HT events:
∆Ne2Ne2
=
[1
Np+
(∆�)2
(1 + �)2
]1/2.
For LT prescaling factor f we find:
∆Ne2Ne2
[f + � + �2
fNp
]1/2.
Conservative choice of EHT = 46 MeV → tail fraction � = 0.02.Setting ∆Ne2/Ne2 = 2× 10−4, rπstop = 20, 000/sec, f = 1/16:
Np = 3.4× 107 andrtrig ∼ 75 (6 months net beam time).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Statistical Uncertainties
Relative statistical uncertainty for Ne2 = (1 + �)Np HT events:
∆Ne2Ne2
=
[1
Np+
(∆�)2
(1 + �)2
]1/2.
For LT prescaling factor f we find:
∆Ne2Ne2
[f + � + �2
fNp
]1/2.
Conservative choice of EHT = 46 MeV → tail fraction � = 0.02.
Setting ∆Ne2/Ne2 = 2× 10−4, rπstop = 20, 000/sec, f = 1/16:
Np = 3.4× 107 andrtrig ∼ 75 (6 months net beam time).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Statistical Uncertainties
Relative statistical uncertainty for Ne2 = (1 + �)Np HT events:
∆Ne2Ne2
=
[1
Np+
(∆�)2
(1 + �)2
]1/2.
For LT prescaling factor f we find:
∆Ne2Ne2
[f + � + �2
fNp
]1/2.
Conservative choice of EHT = 46 MeV → tail fraction � = 0.02.Setting ∆Ne2/Ne2 = 2× 10−4, rπstop = 20, 000/sec, f = 1/16:
Np = 3.4× 107 andrtrig ∼ 75 (6 months net beam time).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN: Systematics Uncertainties
I π/µ decay discrimination: low µ decay pileup, digitizedtarget waveforms
I π/µ decay normalization: Michel energy spectrum,absolute energy calibration (≤ 1× 10−4)
I Acceptance ratio for πe2 and Michel decays: RMD →PIBETA data & analysis (≤ 1× 10−4)
I Hadronic background in the detector: GEANT4 studies(≤ 1× 10−4)
I Time-zero definition and fπd/fsd ratio(≤ 2× 10−4 → ∆t0 = 5 ps)
I Total systematic uncertainty: ≤ 2− 3× 10−4)
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Branching Ratio and π → eν Tail Fraction
Illustration from 2008 data: BR will be determined from HTdata, tail fraction deduced from prescaled LT runs.
Raw histograms show total target energy vs total CsIcalorimeter energy (left: HT, right: LT).
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Timing Spectra
RMS 0.07891
DEG-TGT DSC Time (ns)-1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8 1
Num
ber o
f Eve
nts
0
100
200
300
400
500
600
700
800
900 RMS 0.07891RMS 0.07891
DEG-CsI TDC (ns)0 50 100 150 200
Num
ber o
f Eve
nts
0
10000
20000
30000
40000
50000
HT Trigger+π68 MeV/c
DEG-CsI TDC (ns)0 20 40 60 80 100 120
Num
ber o
f Eve
nts
0
10000
20000
30000
40000
50000
HT Trigger+π68 MeV/c
DEG-CsI TDC (ns)0 20 40 60 80 100 120
Num
ber o
f Eve
nts
0
200
400
600
800
1000 HT Trigger+π68 MeV/c
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Target Waveforms: π → eν Events
Digitizer Channel (0.5 ns/ch)
Deg
rade
r D
igiti
zer
Am
plitu
de
π → e ν
0
10000
20000
30000
40000
50000
60000
350 400 450 500 550 600 650 700
Digitizer channel (0.5 ns/ch)
Deg
rade
r D
igiti
zer
Am
plitu
de
π → e ν
0
10000
20000
30000
40000
50000
60000
400 450 500 550 600 650 700
Digitizer Channel (0.5 ns/ch)
Tar
get D
igiti
zer
Am
plitu
de
π → e ν
0
10000
20000
30000
40000
50000
60000
350 400 450 500 550 600 650 700
Digitizer channel (0.5 ns/ch)
Tar
get D
igiti
zer
Am
plitu
de
π → e ν
0
10000
20000
30000
40000
50000
60000
400 450 500 550 600 650 700
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Target Waveforms: Michel Events
Digitizer channel (0.5 x ns/ch)
Tar
get D
igiti
zer
Am
plitu
de
π → µ → e
0
10000
20000
30000
40000
50000
60000
100 200 300 400 500 600 700
Digitizer channel (0.5 ns/ch)
Tar
get D
igiti
zer
Am
plitu
de
π → µ → e
0
10000
20000
30000
40000
50000
60000
350 400 450 500 550 600 650 700
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANNI Network Structure: ten input neurons, two hidden layers
(10 + 10) and one outputI Inputs: eight charge integrals, number of peaks
(TSpectrum), π+-Stop TimingI Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANN
I Network Structure: ten input neurons, two hidden layers(10 + 10) and one output
I Inputs: eight charge integrals, number of peaks(TSpectrum), π+-Stop Timing
I Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANNI Network Structure: ten input neurons, two hidden layers
(10 + 10) and one output
I Inputs: eight charge integrals, number of peaks(TSpectrum), π+-Stop Timing
I Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANNI Network Structure: ten input neurons, two hidden layers
(10 + 10) and one outputI Inputs: eight charge integrals, number of peaks
(TSpectrum), π+-Stop Timing
I Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANNI Network Structure: ten input neurons, two hidden layers
(10 + 10) and one outputI Inputs: eight charge integrals, number of peaks
(TSpectrum), π+-Stop TimingI Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Artificial Neural Network: Inputs and Output
I Multi Layer Percepton definition - linear ANNI Network Structure: ten input neurons, two hidden layers
(10 + 10) and one outputI Inputs: eight charge integrals, number of peaks
(TSpectrum), π+-Stop TimingI Output: 1 = π+ → e+ν, 0 = π+ → µ+ → e+
double p2e_mpl::value(int index,double in0,double in1, doublein2,double in3,double in4,double in5) {input0 = (in0 - 18.365)/2.02788; ...input5 = (in5 - 2.34097)/0.474034;return ((neuron0xa212580()*1)+0); }double p2e_mpl::neuron0xa212580() {double input = 0.0816982;input += synapse0xa212648(); ...return input } ...
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Discrimination with ANN: Monte Carlo
• ANN training on High Thr. MC data: Ee>48 MeV, tπG>10 ns
• Application on Low Thr. MC data, Ee>10 MeV, tπG>10 ns• Extract efficiency and false positive probability for π+ → e+ν
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A HT Trigger: Signal Background
0.00 percent±=99.98 2eπ∈ 0.01 percent±=0.08 Mm
>10 nsGπ
1E6 MC Events, t
=0.50on
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A LT Trigger: Signal Background
0.16 percent±=99.77 2eπ∈ 0.16 percent±=0.23 Mm
>10 nsGπ
1E6 MC Events, t
=0.95on
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Discrimination with ANN: Monte Carlo
• ANN training on High Thr. MC data: Ee>48 MeV, tπG>10 ns• Application on Low Thr. MC data, Ee>10 MeV, tπG>10 ns
• Extract efficiency and false positive probability for π+ → e+ν
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A HT Trigger: Signal Background
0.00 percent±=99.98 2eπ∈ 0.01 percent±=0.08 Mm
>10 nsGπ
1E6 MC Events, t
=0.50on
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A LT Trigger: Signal Background
0.16 percent±=99.77 2eπ∈ 0.16 percent±=0.23 Mm
>10 nsGπ
1E6 MC Events, t
=0.95on
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Discrimination with ANN: Monte Carlo
• ANN training on High Thr. MC data: Ee>48 MeV, tπG>10 ns• Application on Low Thr. MC data, Ee>10 MeV, tπG>10 ns• Extract efficiency and false positive probability for π+ → e+ν
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A HT Trigger: Signal Background
0.00 percent±=99.98 2eπ∈ 0.01 percent±=0.08 Mm
>10 nsGπ
1E6 MC Events, t
=0.50on
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A LT Trigger: Signal Background
0.16 percent±=99.77 2eπ∈ 0.16 percent±=0.23 Mm
>10 nsGπ
1E6 MC Events, t
=0.95on
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
π → eν Discrimination with ANN: Monte Carlo
• ANN training on High Thr. MC data: Ee>48 MeV, tπG>10 ns• Application on Low Thr. MC data, Ee>10 MeV, tπG>10 ns• Extract efficiency and false positive probability for π+ → e+ν
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A HT Trigger: Signal Background
0.00 percent±=99.98 2eπ∈ 0.01 percent±=0.08 Mm
>10 nsGπ
1E6 MC Events, t
=0.50on
MLP Output-0.2 0 0.2 0.4 0.6 0.8 1 1.2
Nu
mb
er o
f E
ven
ts
1
10
210
310
410
5101A LT Trigger: Signal Background
0.16 percent±=99.77 2eπ∈ 0.16 percent±=0.23 Mm
>10 nsGπ
1E6 MC Events, t
=0.95on
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
Discrimination with Neural Networks: MC Simulation
0 10 20 30 40 50 60 70 80 90 1000
5000
10000
15000
20000
25000
1A HT threshold positron energy Entries 4416831A HT threshold positron energy
0 10 20 30 40 50 60 70 80 90 1000
5000
10000
15000
20000
25000
1A HT Michel positron energy Entries 3294841A HT Michel positron energy
-20 0 20 40 60 80 100 120 140 1600
500
1000
1500
2000
2500
3000
3500
4000
1A HT p2e positron timing Entries 112199
0.09 ns±=25.90 πτ
1A HT p2e positron timing
-20 0 20 40 60 80 100 120 140 1600
500
1000
1500
2000
2500
3000
1A HT Michel positron timing Entries 3294841A HT Michel positron timing
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
Outline Physics Motivation Experimental Apparatus Data & Analysis Summary & Future Plans
PEN Summary & Future Plans
I Developed clean π+ beam tunes with up to 30,000 stoppedπ+/sec at 85 MeV/c momentum.
I Digitized signals of beam detectors: forward (B0) beamcounter, active degrader (AD), and active target (AT).
I Two development runs, in 2007 and 2008, ramping upbeam stop and DAQ rates to design specifications.
I In 2008 run used position-sensitive four-wedge activedegrader, considering replaced it with mini-time-projectionchamber (mTPC) for 2009 data production run.
I Total pions stopped in 2007 and 2008 runs: > 8× 1010. Todate > 4.7× 106 π → eν decays recorded, correspondingto (δB/B)stat < 5× 10−4
I Detailed data analysis under way in preparation for a 2009run, planned to complete the required event statistics.
I PEN Web page: http://pen.phys.virginia.edu
OutlinePhysics MotivationPIBETA Experimental Programe: Theoretical Statuse: Experimental Status
Experimental ApparatusPEN DetectorCentral Detector RegionWaveform Digitizer
Data & AnalysisADC/TDC/DIG SpectraWaveform AnalysisANN Analysis
Summary & Future PlansPEN 2007-2009