Geant4 Simulations for the Radon Electric Dipole Moment Search at

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Current upper limits on the EDMs of the neutron, electron and 199 Hg atom (see Table 1.1) have, in fact, already significantly reduced the allowed parameter spaces of these models. Table 1.1: Current upper limits on the EDMs of the neutron, electron and 199 Hg atom. Species EDM Upper Limit C.L. Neutron < 2.9×10 −26 e·cm [17] 90% Electron < 1.6×10 −27 e·cm [18] 90% 199 Hg Atom < 3.1×10 −29 e·cm [19] 95% 1.2 Atomic EDMs Measuring an EDM in a neutral atom is complicated by orbiting atomic electrons, which arrange themselves to exactly cancel the EDM of a point nucleus. Due to the finite size of the nucleus, however, the screening effect does not completely cancel the observable atomic EDM. The intrinsic Schiff moment, the lowest order time-reversal odd moment of a nucleus that is measurable in a neutral atom [5], is a measure of the difference between the charge and dipole distributions in the intrinsic frame of the nucleus. It is responsible for inducing the observable atomic EDM in the electron cloud. The intrinsic Schiff moment is given by ⃗S intr = 1 10 ∫ er 2 ρ(r)⃗rd 3 r − 1 ∫ d 6Z ⃗ N ρ s (r)r 2 d 3 r , (1.3) where ⃗ d N is the nuclear EDM, ρ(r) is the charge distribution of the nucleus and ρ s (r) the spherically symmetric part of the the charge distribution. It can be thought of as the difference between the charge and dipole distribution in a nucleus of finite size. 6
Figure 1.2: Experimental upper limits for the EDMs of the neutron, electron and 199 Hg atom as a function of time compared to the ranges predicted for typical parameter in various models of particle physics. Adapted from reference [1]. 1.2.1 Radon EDM Enhancements The search for an atomic EDM with odd-A radon isotopes is motivated by the predictions of large enhancements in the observable atomic EDM. Recent theoretical calculations predict anenhancement factor of ∼600 for 223 Rnrelative to 199 Hg [2, 3, 4, 5,6,7], whichisthemostsensitive EDMmeasurement todate[19]. Thisenhancement is derived from three sources: octupole deformation of the nucleus, close-lying parity doublet states in the nucleus, and the large Z of the isotope. 7
Page 1 and 2: GEANT4 SIMULATIONS FOR THE RADON EL
Page 3 and 4: Dictated but not read. i
Page 5 and 6: Contents Acknowledgements ii 1 Intr
Page 7 and 8: 4 Results 60 4.1 γ-Ray Spectroscop
Page 9 and 10: List of Figures 1.1 An illustration
Page 11 and 12: Chapter 1 Introduction Thesearchfor
Page 13 and 14: ˆP ր ˆT ց Figure 1.1: An illust
Page 15: 1.1.1 CP Violation Following the ob
Page 19 and 20: Figure 1.3: Illustration of the dou
Page 21 and 22: Chapter 2 RnEDM Experiment at TRIUM
Page 23 and 24: Figure 2.1: A schematic of the ISAC
Page 25 and 26: a measurement cell. The RnEDM exper
Page 27 and 28: NMR techniques, and supplementing s
Page 29 and 30: Occupied Orbitals Fine Structure Hy
Page 31 and 32: energy levels are separated accordi
Page 33 and 34: (σ + ) along the axis of the B fie
Page 35 and 36: atom and absorbed by another. Radia
Page 37 and 38: anaverageof120kHzphotopeakcountrate
Page 39 and 40: Figure 2.7: One GRIFFIN/TIGRESS HPG
Page 41 and 42: (a) One GRIFFIN detector in the HPG
Page 43 and 44: 3.1 Introduction 3.1.1 Previous Wor
Page 45 and 46: energies, branching ratios, emissio
Page 47 and 48: used around the measurement cell in
Page 49 and 50: 3.2.5 Simulated Data Thecodewaswrit
Page 51 and 52: lower its total energy. Internal co
Page 53 and 54: 10000 1000 2 χ red = 1.21 t 1/2 =
Page 55 and 56: as [47] I(E) = G 2π 3 7 c 6 | M i
Page 57 and 58: was to use an average X-ray energy
Page 59 and 60: 1.5 1.4 1.3 1.2 P = 100% P = 75% P
Page 61 and 62: where (a b c d | e f) are Clebsch-G
Page 63 and 64: 2 2 1.5 J i = 5/2, J f = 5/2 J i =
Page 65 and 66: of radius 10 cm, allowing the GRIFF
Page 67 and 68:
(a) Screenshot showing the detector
Page 69 and 70:
3.6.2 Output Data and Sort Codes Th
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(user-defined option), secondly toa
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30 Absolute Efficiency (%) 25 20 15
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11 10 9 8 7 6 5 4 3 2 1 0 1e+06 Cou
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4.2.1 Multipolarity Effects The sha
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Figure 4.7: The time projections an
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distribution, this average intensit
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Table 4.1: The fit results for the
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12 10 linear regression: y = 0.2243
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15 Linear Counts (e+04) 10 5 0 1e+0
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Chapter 5 Conclusions and Future Di
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simulated given sufficient parent a
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Appendix A Figure A.1: Simulated de
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Figure A.3: Simulated decay scheme
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Figure A.5: Simulated decay scheme
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6 out = (1/(1+∆ˆ2))*(f(k,jf,L1,L
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44 return; 45 end 46 if abs(m) > j
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1 % LegendreP.m 2 function P = Lege
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39 xx(i+1,j+1) = r(i+1,1)*sin((i*re
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11 %warning('m1 + m2 + m3 must equa
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23 end 24 % ////////// 25 j1 = J1;
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33 if L1 == L2 && ∆ == 0 34 title
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Bibliography [1] J. M. Pendlebury a
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[25] P. G. Bricault, M. Dombsky, Je
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[47] RichardA.Dunlap. An introducti
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