Mｏｔｔ散乱によるParity対称性の破れを検証

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ともひろこうじょう
5 years ago
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1 Mott Parity P2 Mott

2 target Mott Parity

3 Parity Γ = t P P ),,, ( γ γ γ γ γ γ ν ν µ µ = = Γ 1 : : : Γ P P P P x x P ν ν µ µ vector axial vector ν ν µ µ γ γ Γ ν γ 5 ν µ µ γ γ γ 5 Γ vector axialvector Parity Lagrangian Parity ( V V, A A ) ( V A )

4 Mott setting x-y target y y = =14 =22.5n (0 n 14) =0, 0 =90 PMT B spin Mott ) > 0 PMT C z e Beam PMT A x y

5 z = 65 )

6 Rutherford dσ 0( θ ) dω = ( Zαm) r p sin 2 θ 2 α = 2 e 4πε 0hc Dirac µ ( µ ν ν µ µν ( γ ( i qa ) m) ψ = 0 γ γ + γ γ = 2g ) µ µ spin

7 Mott [ ] [ ] { } [ ] [ ] ) ( ) ( ) ( ) ( ) ( ) (cos 1) ( 1) ( 2 ln sin exp ) (1 ) (1 cot 2 ) ( ) (cos 1) ( 1) ( 2 ln sin exp ) (1 ) (1 2 ) ( ) ( ) ( ) ( ) ( sin ) ( ) )sin( ( 1 ) ( : ) )sin( ( 1 2 sin 4 ), ( ) ( 0 α ρ ρ ρ ρ θ θ θ θ β α θ θ θ θ θ βγ α θ φ φ θ β θ σ φ φ φ θ θ α φ θ σ πρ π θ θ θ θ σ = + Γ Γ + + Γ Γ + = Γ Γ = Γ Γ = + = + Ω = = Ω = + = + Ω k iq iq iq e iq k iq k iq k e D P D k D k i iq iq iq q G P D k kd i iq iq iq i F Z q G F G F Z S S d d P PS p m Z d d k k k k i k i k k k k k k k k k k k k d d D

8 Mott

9 S

10 - u d p u n p + e + ν e u n d d e 0 helicity = +1/2 W ν e momentum spin e np -e momentum spin Source Electron emissions from the Hg-203 to Tl-203 decay, measured by A. H. Wapstra, et al., Physica 20, 169 (1954).

11 P N( N( ) ) + N( N( ) ) Lagrangian ( ) L int = G F 2 µ µ µ 5 µ 5 jµ j ( j = e γ (1 + αγ ) ν + p γ (1 + αγ ) ) n P = * α + α 1+ α 2 β V A current ( ) P = β

12 spin E r B r spin velocity spin velocity + + = E g B g B g mc es dt s d r r r r r r r r β γ γ β β γ γ γ 1 2 ) ( spin Thomas

13 spin r ds dt = e 1 r s mc γ + 1 E 90 r r ( β ) θ s π γ 1 = 2 γ spin spin velocity E r P = β β cosθ s

15 energy

16 1st: 2nd: 3rd:

21 poisson

24 d=15 d=30 d=10 d=10

26 kv V

27 Source 137 Cs Photo Multiplier C kV electrode Source

28 137 Cs

29 energy (kev) Mean (ch) Sigma (ch) ) kev/ch 0keV ch

30 0kV

31 20kV 25kV

32 30kV 35kV

33 Voltage (kv) Mean (kev) Sigma (kev) (kev) ( 2) 30.2( 1.4) ( 2) 39.8( 1.4) ( 1) 48.7( 1.0) ( 1) 57.3( 0.8)

35 PMT C PMT A Back Scattering

36 58mm PMT B PMT C PMT A PMT A,B 65 Scintillator 0.25mm % PMT PMT C Scintillator 5mm

37 70mm 15mm Null Asymmetry 0.01mm Background Asymmetry mm

39 OR PMT A PMT B AMP AMP DISC A D C Computer PMT C AMP DISC ADC AMP 10 Discriminator Threshold 80mV(A) 500mV(B) Gate Signal ADC Gate Signal AMP Computer Channel

40 137 Cs 30.2y MeV 94% Mev 6% Mev 85%

41 Pa 3. 30kV 4. AMP, Discriminator, ADC PMT 1kV 5.,, Count Rate 2 (Computer PMT A PMT B Count Rate ) ,180,

42 *** CORPORATION Source PMT A B energy peak C B A Source(137Cs)

43 *** CORPORATION Photo multiplier A Source 137 Cs

44 *** CORPORATION Photo multiplier B Source 137 Cs

45 *** CORPORATION

46 *** CORPORATION Photo multiplier A Source 137 Cs

47 *** CORPORATION Photo multiplier A - threshold 60mV

48 *** CORPORATION Photo multiplier B Source 137 Cs

49 *** CORPORATION Photo multiplier B - threshold 500mV

50 *** CORPORATION 0 : PM A : PM B : PM C

51 *** CORPORATION 90 : PM A : PM B : PM C

52 *** CORPORATION 180 : PM A : PM B : PM C

53 *** CORPORATION 270 : PM A : PM B : PM C

54 *** CORPORATION

55 *** CORPORATION PM A = 0 Au Al

56 *** CORPORATION PM A = 0

57 *** CORPORATION PM A = 0 Au Al

58 *** CORPORATION PM B = 0 Au Al

59 *** CORPORATION PM B = 0

60 *** CORPORATION PM B = 0 Au Al

61 *** CORPORATION

62 *** CORPORATION

63 *** CORPORATION

64 *** CORPORATION

65 *** CORPORATION PM A

66 *** CORPORATION PM B

67 *** CORPORATION

68 *** CORPORATION

Drift Chamber

Quench Gas Drift Chamber 23 25 1 2 5 2.1 Drift Chamber.............................................. 5 2.2.............................................. 6 2.2.1..............................................