Time-modulation of electron-capture decay factor detected at GSI, Darmstadt Byung Kyu Park Department of Physics University of California, Berkeley Physics 250 March 20, 2008 Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 1 / 19
38
Embed
Time-modulation of electron-capture decay factor detected ...budker.berkeley.edu/Physics250_Spring08/Andrew Park... · Time-modulation of electron-capture decay factor ... 3 Neutrino
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Time-modulation of electron-capture decay factordetected at GSI, Darmstadt
Byung Kyu Park
Department of PhysicsUniversity of California, Berkeley
Physics 250March 20, 2008
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 1 / 19
Outline
1 The Experiment
2 Hypotheses
3 Neutrino Oscillation
4 Prospects
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 2 / 19
The Facility
Gesellschaft für Schwerionenforschung, Darmstadt1
1http://www.gsi.de/Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 3 / 19
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 8 / 19
Experimental result
with 140Pr58+
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 9 / 19
Experimental result
with 140Pr58+
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 9 / 19
Experimental result
with 140Pr58+
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 9 / 19
Experimental result
with 140Pr58+
Exponential decay with a modulation at a period of ≈ 7 s.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 9 / 19
Experimental result
with 142Pm60+
Inset shows Fourier transform of the datashowing a peak at f = 0.14 Hz again.
Data with the sinusoidal fit for first 36seconds
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 10 / 19
Experimental result
Fit parameters
Fit parameters of 140Pr dataEq. N0λEC λ a ω χ2/DoF1 34.9(18) 0.00138(10) - - 107.2/732 35.4(18) 0.00147(10) 0.18(3) 0.89(1) 67.18/70
Fit parameters of 142Pm dataEq. N0λEC λ a ω χ2/DoF1 46.8(40) 0.0240(42) - - 63.77/382 46.0(39) 0.0224(41) 0.23(4) 0.89(3) 31.82/35
Null hypothesis of pure exponential decay is excluded to 99%confidence level based on χ2 tests.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 11 / 19
Hypotheses: (1) technical artifact?
Procommon period of 7 s for140Pr58+ and 142Pm60+.
Conapparatus sensitive to singleionPr and Pm ions coast ondifferent orbits in ESRuncertainty of decay time(≈ 1 s) less than observedperiod.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 12 / 19
Hypotheses: (1) technical artifact?
Procommon period of 7 s for140Pr58+ and 142Pm60+.
Conapparatus sensitive to singleionPr and Pm ions coast ondifferent orbits in ESRuncertainty of decay time(≈ 1 s) less than observedperiod.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 12 / 19
Hypotheses: (2) quantum beat of hyperfine states
Pro140Pr and 142Pm have nuclearspin I = 1.H-like ions probably producedin coherent superposition oftwo 1s hyperfine states withF = 1/2 and F = 3/2.Final state (daughter ion plusνe) has F = 1/2.EC-decay from F = 3/2 stateis not allowed.
ConThe well-known hyperfinesplitting in hydrogen is inmicrowave range(ν = ∆E/h = 1420 MHz), withperiod of,
T = h/∆E = 0.7 ns,
and T for 140Pr58+ is evensmaller by a factor of ≈ 105.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 13 / 19
Hypotheses: (2) quantum beat of hyperfine states
Pro140Pr and 142Pm have nuclearspin I = 1.H-like ions probably producedin coherent superposition oftwo 1s hyperfine states withF = 1/2 and F = 3/2.Final state (daughter ion plusνe) has F = 1/2.EC-decay from F = 3/2 stateis not allowed.
ConThe well-known hyperfinesplitting in hydrogen is inmicrowave range(ν = ∆E/h = 1420 MHz), withperiod of,
T = h/∆E = 0.7 ns,
and T for 140Pr58+ is evensmaller by a factor of ≈ 105.
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 13 / 19
Hypotheses: (3) neutrino oscillation
Suggestive kinematic considerationFor two mass eigenstates, m1 and m2,{
Experimental verification“It is obvious that our findings must be corroborated by the studyof other two-body beta decays (EC and βb).”9
“A similar analysis can be applied to a K-capture experiment ...Here there are a number of initial states having different degreesof ionization. Interference can only occur between initial stateshaving the same degree of ionization. Otherwise the analysis isthe same.”10
New method for studying neutrino mixingIf the effect is real and realistic theoretical model can be set up,this is a new method to study neutrino oscillation without the needto directly detect neutrinos.
9Yu. A. Litvinov et al., arXiv:0801.2079v110Lipkin, arXiv:0801.1465v2Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 18 / 19
Litvinov, et al., “Observation of non-exponential orbital electroncapture decays of hydrogen-like 140Pr and 142Pm ions,”http://arxiv.org/abs/0801.2079v1
Ivanov, et al., “On the time-modulation of the K-shell electroncapture decay of H-like 140Pr58+ ions produced by neutrino-flavourmixing,” http://arxiv.org/abs/0801.2121v1Giunti, C., “Comment on the neutrino-mixing interpretation of theGSI time anomaly,” http://arxiv.org/abs/0801.4639v2(Note: this comment refers to arXiv:0801.1465v1.)Lipkin, H. J., “New method for studying neutrino mixing and massdifferences,” http://arxiv.org/abs/0801.1465v2
Byung Kyu Park (UC Berkeley) Time-modulation of EC decay Physics 250 March 20, 2008 19 / 19