charge symmetry breaking/isospin nonconservation
Post on 14-Jan-2016
75 Views
Preview:
DESCRIPTION
TRANSCRIPT
Charge Symmetry Charge Symmetry Breaking/Isospin Breaking/Isospin NonconservationNonconservation
Willem T.H. van Oers
ECT June 13-17, 2005*
1)1) IntroductionIntroduction
2)2) Classification of N-N ForcesClassification of N-N Forces
3)3) Evidence for Class III InteractionsEvidence for Class III Interactions
4)4) Evidence for Class IV InteractionsEvidence for Class IV Interactions
5)5) Time Reversal InvarianceTime Reversal Invariance
6)6) Charge Symmetry Breaking and Charge Symmetry Breaking and HypernucleiHypernuclei
System
Isospin:
2
1,
2
13 II According to their
chargeCharge Independence:
0],[ IH or ppnpnn
Charge Symmetry:
,2Iics eP ,0],[ csPH ,pnnp ppnn
system, isospin conserved, no mixing of I=0,1 states np
N System
2
1,
2
3I
Charge Symmetry
np np pnnp 00
pn, :
NN
Hadron Multiplet Mass Splittings
At the quark level: M
0K
du || ; ud ||
Hadron Valence Quarks Mass(MeV)
(MeV)
sd 497.648(22)+3.972(27)
K0* )892(K
D0D0BB
np
00
)892(*K
0
su
sd
cd
su
cu
bdbu
duduud
ddsuds
dusuus
dssuss
493.677(16)
896.10(27)891.66(26)
1869.4(5)1864.6(5)
5279.4(0.5)5279.0(0.5)
939.56536(8)938.27203(8)
1197.449(30)1192.642(24)
1192.642(24)1189.37(7)
1321.31(13)1314.83(20)
+4.44(37)
+4.78(10)
-0.33(28)
+1.2933317(5)
+4.807(35)
+3.27(8)
+6.48(24)
Note Coulomb effects have the opposite sign; for the np system MeVM Coul
np 6.0
One concludes therefore
MeVmm ud 4
But then at the quark level in the scheme at the scale of 2 GeV
%30
ud
du
mm
mCSB !
45.1 um
84 dm
MeV
MeV
%1)(
tconstituenud
du
mm
mHowever
which is the scale of CSB in hadrons and nuclei
The electromagnetic interaction among the quarks also plays a role
du|| dduu|
2
1| 0
Coulomb repulsion Coulomb attraction)35(57018.139
m
mm 0
)6(9766.1340 m
] No contribution from dum !
du||
MS
The electromagnetic interaction among the quarks is of importance also for the mass splittings of
|
|and 0|
)5.0(8.775 m
)6.1(3.150
0| a
0| a
and
00| a
)2.1(7.9840
am
10050
dum Gives isospin mixing of the neutral mesons
)1,0()1,1( 00 )0,0()0,1( '0
dum Allows for G-parity violating decays 0
dum Also predicts
0)]()([
2
1)()(
xuxd
xuxd
np
np
! 0.05-0.10 ?
implications for the G0 experiment:
possible experiments:
Induced Drell-Yan processes at 30 GeV(FNAL, JPARC)
compare
{Xp Xn
i.e.i.e.
pdd nuu
or W production in np collider
i.e.
i.e.
Wdupn
v Wud
np
W Wp n
CLASSIFICATION OF N-N FORCES:
CLASS I: CHARGE INDEPENDENT FORCES
)2()1( ttbaVI npppnn
CLASS II: CHARGE SYMMETRIC BUT CHARGE DEPENDENT FORCES
)]2()1(3
1)2()1([ 33 ttttcVII
npppnn CLASS III: ISOSPIN CONSERVING BUT CHARGE
)]2()1([ 33 ttdVIII npppnn
-NO ISOSPIN MIXINGCLASS IV: ISOSPIN NON-CONSERVING, CHARGE ASYMMETRIC
333 )]2()1([)]2()1([ ttgtteVIV
0IVV FOR IDENTICAL PARTICLES(nn&pp)
-AFFECTS NP SYSTEM ONLY
)1,2()2,1( IVIV VV
ASYMMETRIC AND CHARGE DEPENDENT FORCES
AND CHARGE-DEPENDENT FORCES
The Two-nucleon system and Isospin
1 0 -1T
1
0
pp
np
nn
np
3T
space spin
isospin
np
T=1
np
T=0
S
A
S
A
A
S
S
A
S
S
A
AClass IV charge-asymmetric, charge dependent interactions:1) Affect np system only2) Cause isospin mixing3) Or cause spin triplet-singlet transitions
Evidence for Class III Interactions
1) Low energy nucleon-nucleon scattering observables
2) Okamoto-Nolen-Schiffer effect:
Binding energy differences of mirror nuclei
Low Energy Nucleon-Nucleon Scattering Observables
nn nn np pp pp
)( fma
)( fmr
)32(45.18
)11(80.2 )11(75.2 )5(75.2 )14(794.2
)3(8.18 )9(748.23 )26(8063.7 )4(3.17
)4(85.2
n-p Elastic Scattering
Basic Principle of the CSB Experiments:
CS Operation
Rotation
nA pA
p ppn n n
pn AAA
,0 ACS CSBA 0
)( pnpn PPAPA
zxA
xyz
xzA
xz
y)()()( zxxz AAC
Mechanisms of charge symmetry breaking in n-p elastic scattering
Charge asymmetric, charge dependent interaction, antisymmetric under the exchange of nucleons i and j in isospin space, class IV interaction of Henley and Miller
fk
ik
fk
ik
)1
(1
)]2()1()][2()1([44 332
2
rdr
d
rL
M
KeV n
)770(0 1,1 JT
)782(0 1,0 JT
0 0
emH
)(11
)]2()1()][2()1([||
44 3322
0
2rmrmemn ee
rdr
d
rL
mm
H
M
KggV
)
1(
1)]2(*)1([)]2(*)1([
24 32
2rme
rdr
d
rL
M
gV
)()]2()1()][2()1([ 33' rLVIV
Neutron-proton magnetic interaction 00 mixing
Angular distribution
)(A similar to
)(A MeVTn 300
)()]2(*)1()][2(*)1(['' rLVIV
Neutron-proton mass difference a and exchang
e State dependent phase J)1( so
'i s have different signs
according J values
affecting
Iqbal & Niskanen’s Prediction at 350 MeV
by comparing the experimental results for A With theoretical
predictions ,one can establish an upper limit on a P-even/T-oddinteraction[M.Simonius,Phys.Rev.Lett.78,4161(1997)]
this translates into a P-even/T-odd N coupling constant
in terms of the strong N coupling constant3107.6|| g [95% C.L.]
Note that the upper limit on the neutron edm gives
|/|1053.0|| .3 measDDH ffg
but ?15|/| . measDDH ff
So comparable results!
2 new possibilities1 measure A in pnpn at 320 MeV with improved
precision.2 measure the attenuation of polarized proton through an aligned deuterium target
2/
)Im()Re(
0
**
hcfb
AA ooonoono
AAAAA pnooonoono
A (TRI violation) [410)4.78.1(
410)106( 410)238(
183 MeV347 MeV477 MeV
2/
)Im()(
0
*
hc
TRIVA
Take c from SAID FA95 solution::8.72,347 0 cmMeV
110314.0)Re( c110369.0)Im( c
677.10
fmfm
srmb /183 MeV347 MeV477 MeV
410)8320( g410)3722(
410)7727( or 0067.0|| g (95% C.L.)neutron electric dipole moment gives an indirect limit of 310g(dependent on '
f !)
|/|1053.0|| 3 ffg DDH
Considerably lower than the limits inferred from direct tests of TRI
Binding Energies(MeV), Mirror Hypernuclei
H4
Li8
Li9
Be10
B12
He4
Be8
B9
B10
C12
04.004.2
03.080.6
15.053.8
22.011.9
06.037.11
03.039.2 05.084.6
15.088.7
12.089.8
19.076.10
If isospin is an exact symmetry and therefore also no N
CSB, then the B of mirror hypernuclei should be identical.
Differences could be due to:- Coulomb effects + other electromagnetic effects- nuclear CSB
N- CSB
top related