View
50
Download
9
Category
Tags:
Preview:
DESCRIPTION
M. Fukugita (ICRR, Univ. of Tokyo) and T.K. (October 4, 2005 at “RADCOR 05”). Radiative Corrections to Neutrino-Deuteron Scattering Revisited. (i) Acta Physica Polonica B35 (2004 )1687 (ii) Phys. Letters B 598 (2004) 67 (iii) hep-ph/0509123 ( to appear in Phys. Rev. D). 1.Introduction - PowerPoint PPT Presentation
Citation preview
1
Radiative Corrections to Neutrino-Deuteron Scattering Revisited
M. Fukugita (ICRR, Univ. of Tokyo) and T.K.
(October 4, 2005 at “RADCOR 05”)
(i) Acta Physica Polonica B35 (2004 )1687
(ii) Phys. Letters B 598 (2004) 67
(iii) hep-ph/0509123 ( to appear in Phys. Rev. D)
2
1.Introduction
Neutrino experiment after ~2000 Precise measurement at low energy (1-1
0 MeV) weak processes
(i) KamLAND (Kamioka Liquid Scintillator Anti- Neutrino Detector)
→ F. Suekane’s talk
(ii) SNO (Sudbury Neutrino Observatory)
(iii) etc., ……
3
Low-Energy Neutrino Reactions
KamLAND……
SNO………….
4
1. Knowledge of the cross sections with 1 % accuracy or less is required for neutrino physics.
→ radiative corrections are important.
2. Clarify the electroweak radiative corrections in :
5
2. Radiative Corrections
• HistoryNeutron beta decay….. Kinoshita and Sirlin (’59) (four-Fermi theory for nucleons)Super-allowed Fermi transition ….. Sirlin (~’80) (Weinberg-Salam theory)KamLAND …. Vogel , Fayans (’84)SNO………… Towner (’98) , Kurylov et al., (‘02)
One term has, however, eluded all of the previous studies (in the Gamow-Teller part).
6
3. Inverse beta decay
Static nucleon limit, four-Fermi theory
positron energy, = positron velocity
Tree:
V-A Int.:
7
8
“Renormalization” effects
• For CC processes
• For NC processes
9
• measurement of neutron beta decay asymmetry
c.f. M.Fukugita and T.K. (’04)
10
• Outer corrections ・・・・・・ velocity-dependent, UV-finite even in four-Fermi theory , unambiguously caculable (indep. of strong int.)
• Inner corrections ・・・・・・ just numbers depend on strong interaction dynamics UV-div. in four-Fermi-Theory
Missing in all of the previous studies
11
12
4. Calulational Strategy
(i) QED Corrections: Use the four Fermi int. for nucleons, M=UV cutoff UV-divergent, IR convergent(ii) Electroweak corrections: Weinberg-Salam theory for quarks
Q: How to connect (i) and (ii) smoothly ?
13
14
15
Eliminating M-dependence
(1) Eliminated by using Weinberg-Salam theory
(2) Eliminated by using a model of extended nucleon ⇒ model dependent (nucleon form factor etc.)
The current algebra technique, CVC, and PCAC make the classification into (1) and (2) unique. c.f., Sirlin, Abers et al. (’67) for Fermi-transition M. Fukugita and T.K. (’04) for GT-transition
16
Effects of Strong Dynamics appear only in:
(1) e.m. form factors
(2) weak form factor
17
The inner corrections:
18
5. Neutral current phenomena
(SNO)
No vertex corrections, no bremsstrahlung No outer corrections, no QED type corr. only Weinberg-Salam type corrections
W. Marciano and A. Sirlin (1980)
19
20
21
22
Radiative Corrections to NC cross section:
23
6. Summary
• Established the strategy of calculating the inner corrections for G-T transitions
• Clarified the meaning of
• Showed how to include correctly the inner corrections in the SNO NC-cross section
24
25
26
27
28
5. UV-divergences in four-Fermi theory
Naiive calulation (without Weinberg-Salam)
29
Universality of UV-divergence
(1) Abers et al. (’65) ・・・ Fermi transition
CVC, current algebra ⇒ log-div. is independent of the strong dynamics
(2) Fukugita and TK (’04) ・・・ Gamow-Teller transition
PCAC, current algebra, BJL tech.⇒ log-div is
independent of the strong dynamics
30
5. The Assymmetry measurement
Asymmetry in polarized neutron decay
Asymm= at tree level
at one-loop
31
6. New SNO analyses
nucl-ex/0502021 (salt phase SNO data)
The inner corrections were not correctly taken
into account in their analysis.
Recommended