teilchenphysik – ohne beschleuniger und kosmologie 31.5.07 sommersemester 2007
TRANSCRIPT
Teilchenphysik – ohne Beschleuniger
und Kosmologie
31.5.07Sommersemester 2007
Hartmut Abele, University of Heidelberg 2
2. CP-Verletzung
Hartmut Abele, University of Heidelberg 3
3. Symmetries and the World according to 3. Symmetries and the World according to
EscherEscher
mirror image time time
H.W. Wilschut
matter anti-matterstartidentical to start
anti-particle particle e+ e-
Time reversal violationcan be measured at low energies
P C T
Hartmut Abele, University of Heidelberg 4
BABAR 2001
Hartmut Abele, University of Heidelberg 5
3. Prinzip: CP-Verletzung
(P - known)P -+
elementary particle
+-
spin
EDM
+- T +
- (CP big deal)
CP ↔ T
S. Paul, TUMS. Paul, TUM
Hartmut Abele, University of Heidelberg 6
ILL: the EDM experiment
Hartmut Abele, University of Heidelberg 7
Final Sussex-RAL-ILL result
(C.A. Baker et al. PRL 97(2006) 131801)
| dn | < 2.9 x 10-26 ecm (90% CL)
use of 199Hg co-magnetometer
d(199Hg) < 8.7 × 10-28 ecm
50 pT
Hartmut Abele, University of Heidelberg 8
EDM: PSI
F overall = 100 ,1.1,3.1,2,40
)(
2
12
FFFF
EPNd
PEN
Hartmut Abele, University of Heidelberg 9
The PNPI experiment
•Polarize neutrons || B0 while filling the bottle
•Apply B(wt) B0 to get neutron spin to B0
•Wait for a time T (~100 s): spin precesses about B0
•Apply B(wt) to get neutron spin || to B0; if w wL = (w - wL )T
•Analyze polarization: P = P0 cos()
EDM
Hartmut Abele, University of Heidelberg 10
Improvements
• higher degree of polarization – triple polarizers: a = 0.75 • higher electric field E - new material (CERAN): E = 10 kV/cm • more neutrons N - FRM II + UCN source, more efficient neutron guides
• longer storage time T - better coating, better stability of B0: T 150 s
• Systematic errors: stable B0 (3fT!) - 3He magnetometer with SQIDs
(W. Heil, Mainz), better shielding, polarization and analysis
with the same arrangement
n( )2
dE T N
Mainly performed by the group at PNPI (V. Lobashev et al.):official collaboration agreement with TUM
Hartmut Abele, University of Heidelberg 11
Überblick zur die Sensitivität von Neutronexperimenten
EDM: Energy: E ~0.000 000 000 000 000 000 000 1eV = 10-22 eVn-Ladung: Impuls: p/p ~ 10-11 (Winkelauflösung von 1Å auf 10m)Feinstrukturkonstante / ~ 10-8 (Messung von: nvn)
Quark-Mischung Vud ~ 7 x 10-4
Lebensdauer / ~ 10-3
Gravitation und QM g/g ~ 10-2
Hartmut Abele, University of Heidelberg 12
EDM Strong CP problem
Axion als pseudoskalares Teilchen
Hartmut Abele, University of Heidelberg 13
Axion limits 2007PVLAS
UCN
other limits
Baeßler et al.Westphal, Baeßler, H.A.
arXiv:hep-ph/0703108
Hartmut Abele, University of Heidelberg 14
0%
50%
100%
'down' 'strange' 'bottom'
down strange bottom
2. Prinzip: Mischung der Quarks
-Zerfall: ~ GF2
n-Zerfall:~ 0.95. GF2 = cos2C
. GF2
K-Zerfall: :~ 0.05. GF2 = sin2C
. GF2
ud us ub
cd cs cb
td ts tb
V V VV V VV V V
d d
s s
b b
|Vud|2 + |Vus|
2 + |Vub|2 = 1-|Vud|
2 + |Vus|2 + |Vub|
2 = 1-
Quarkmischung ist Rotation im Flavour-Raum (Null-Summe)CKM-Matrix ist unitär!
Hartmut Abele, University of Heidelberg 15
Unitarity Check: The Quark Mixing CKM MatrixUnitarity Check: The Quark Mixing CKM Matrix
Parametrization: 3 angles, and a phase
A, , are real
Hartmut Abele, University of Heidelberg 16
Unitarity Check II:
PDG: = 59° 13°, = 24° 4°PDG: = 59° 13°, = 24° 4°
VVVVVVVVV
tbtstd
cbcscd
ubusud
U CKM
VVVVVVVVV
tbtstd
cbcscd
ubusud
U CKM
Hartmut Abele, University of Heidelberg 17
Unitarity Check II
dsf
Vud= 1 - 2/2
From A. Buras, Munich
Hartmut Abele, University of Heidelberg 18
Unitarity check
Mixing of quarks = rotation in flavor-space:
Test in first row: |Vud|2 + |Vus|2 + |Vub|2
≈ cos2θ + sin2θ + 0 < 1 ?
: Cabibbo
95%
5%0.00001%Vub
Vus
Vud
VVVVVVVVV
tbtstd
cbcscd
ubusud
U CKM
VVVVVVVVV
tbtstd
cbcscd
ubusud
U CKM
Hartmut Abele, University of Heidelberg 19
Situation 1995 - 2004
+ +
Neutron -Zerfall
0 0 Kern -Zerfall
Pion -Zerfall
0.0
0.9717(13)
0.9738(4)
0.9728(
040 0.
3 )
001
0
2
ud
ud
ud
V
V
V
Hartmut Abele, University of Heidelberg 20
The PDG feels it has the right to redefine anything it wantsThe PDG feels it has the right to redefine anything it wants
Is there a general decline of standards?Is there a general decline of standards?
1994:The “centimeters” on the ruler on p. 227 of the booklet are 0.97 cm long, because:
a) The booklet were returned from the printer at 0.25 times the speed of light
a) A theorist is in charge of the PDGb) The PDG feels it has the right to redefine anything it wantsc) There is a general decline of standardsd) There was an international conspiracye) It was a congressionally mandated cost-saving measuref) PDG gives you more cm/inch than anyone else
Hartmut Abele, University of Heidelberg 21
Vus
Kaon semileptonic decays- K+0l+l
- K0L-l+l sul+l
= (2.12±0.08%), = -2.0% for K+ and 0.5% for K0
)1)(1()0(π192
2
125
3
2
RkusF IfCmVG
)1)(1()0(π192
2
125
3
2
RkusF IfCmVG
I+ = 0.1605 ± 0.0009, I0 = 0.1561 ± 0.0008 = (2.56 ± 0.033)10-15 MeV, =(4.937 ± 0.053)10-15 MeV f(0) = 0.961 ± 0.008, f(0) = 0.963 ± 0.004 Vus = 0.2196 ± 0.0017exp ±
0.0018th = 0.2196 ± 0.0026 (PDG 2002)
Vus = 0.2196 ± 0.0017exp ± 0.0018th = 0.2196 ± 0.0026 (PDG 2002)
Hartmut Abele, University of Heidelberg 22
Some news in 2005: Vus
bb
Hartmut Abele, University of Heidelberg 23
CKM unitarity summary
Phase of consolidationAchievements:- New K results
- New A result
- Halving of the theoretical error in radiative corrections
Continue to measure lifetime and correlation coefficients until limited by theoryLifetimeFormfactors
Hartmut Abele, University of Heidelberg 24
NeutronlebensdauerMethode: UCN in FlaschenPräzision / ~ 10-3
0 exp( ( ))N tt
N t
1 11l ssn o
TUM
~ 99.99 % elastische Reflexion~ 0.01% inelastische Reflexion
in meV-Bereich ~ 0.001% Absorption
885.7 ± 0.7 sec 885.7 ± 0.7 sec 878.5 ± 0.8 sec 878.5 ± 0.8 sec
TUM: magnetische Speicherung: keine VerlusteTUM: magnetische Speicherung: keine Verluste
Hartmut Abele, University of Heidelberg 25
2 values878.5 ± 0.8 sec Serebrov et al.885.7 ± 0.7 sec PDG 2005
= 2 x 10= 2 x 10-6-6
1975 1980 1985 1990 1995 2000 2005865
870
875
880
885
890
895
900
neu
tro
n li
fetim
e v
alu
es
[s]
year
cold beam UCN
Hartmut Abele, University of Heidelberg 26
Neutrons and Big Bang Nucleo Synthesis
Problem 1s after Big Bang:- What does a gas of n and p, when
the universe expands and the temperature drops?
Inputs:- neutron lifetime
- Cross sections
- neutrino cross-sections 1/
- nuclear physics 0.1 – 1 MeV (measured!)
Outputs: H, D, He, Li- number of particle families N
- density of (ordinary) matter in universe
Hartmut Abele, University of Heidelberg 27
In more detail
Weak reaction rate n + e+ p + e n + e p + e
Hubble expansion rateEquating gives freeze out temp.Free neutron beta-decay
Neutron lifetimeNeutron lifetimePDG 2006PDG 2006
Serebrov et al.Serebrov et al.20052005
1 2 2 2~ (1 3 )ud F AgV G
astro-ph/0408523 v2
Yp= 0.2463(6)Yp= 0.2479(6)