Charge Symmetry Breaking/Isospin Nonconservation Willem T.H. van Oers ECTJune 13-17, 2005

1)Introduction 2)Classification of N-N Forces 3)Evidence for Class III Interactions 4)Evidence for Class IV Interactions 5)Time Reversal Invariance 6)Charge Symmetry Breaking and Hypernuclei

System Isospin: According to their charge Charge Independence: or Charge Symmetry: system, isospin conserved, no mixing of I=0,1 states System Charge Symmetry

Hadron Multiplet Mass Splittings At the quark level: Hadron Valence Quarks Mass(MeV)(MeV) (22) (27) (16) (27) (26) (5) (5) (0.5) (0.5) (8) (8) (30) (24) (7) (13) (20) +4.44(37) +4.78(10) -0.33(28) (5) (35) +3.27(8) +6.48(24)

Note Coulomb effects have the opposite sign; for the np system One concludes therefore But then at the quark level in the scheme at the scale of 2 GeV CSB ! However which is the scale of CSB in hadrons and nuclei The electromagnetic interaction among the quarks also plays a role Coulomb repulsionCoulomb attraction No contribution from !

The electromagnetic interaction among the quarks is of importance also for the mass splittings of and and

Gives isospin mixing of the neutral mesons Allows for G-parity violating decays Also predicts ! ? implications for the G0 experiment: possible experiments: Induced Drell-Yan processes at 30 GeV(FNAL, JPARC) compare i.e. orproduction in np collider i.e.

CLASSIFICATION OF N-N FORCES: CLASS I: CHARGE INDEPENDENT FORCES CLASS II: CHARGE SYMMETRIC BUT CHARGE DEPENDENT FORCES CLASS III: ISOSPIN CONSERVING BUT CHARGE -NO ISOSPIN MIXING CLASS IV: ISOSPIN NON-CONSERVING, CHARGE ASYMMETRIC FOR IDENTICAL PARTICLES(nn&pp) -AFFECTS NP SYSTEM ONLY ASYMMETRIC AND CHARGE DEPENDENT FORCES AND CHARGE-DEPENDENT FORCES

The Two-nucleon system and Isospin 10 T 1 0 ppnpnn np spacespinisospin np T=1 np T=0 S A S A A S S A S S A A Class IV charge-asymmetric, charge dependent interactions: 1) Affect np system only 2) Cause isospin mixing 3) 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

n-p Elastic Scattering Basic Principle of the CSB Experiments: CS OperationRotation pppn nn

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

Neutron-proton magnetic interaction mixing Angular distributionsimilar to Neutron-proton mass difference a andexchange State dependent phasesos have different signs according J values affecting

Iqbal & Niskanen ’ s Prediction at 350 MeV

by comparing the experimental results forWith theoretical predictions,one can establish an upper limit on a P-even/T-odd interaction [M.Simonius,Phys.Rev.Lett.78,4161(1997)] this translates into a P-even/T-oddcoupling constant in terms of the strongcoupling constant [95% C.L.] Note that the upper limit on the neutron edm gives but So comparable results! 2 new possibilities 1 measureinat 320 MeV with improved precision. 2 measure the attenuation of polarized proton through an aligned deuterium target

(TRI violation) 183 MeV 347 MeV 477 MeV Take c from SAID FA95 solution: 183 MeV 347 MeV 477 MeVor(95% C.L.) neutron electric dipole moment gives an indirect limit of (dependent on!) Considerably lower than the limits inferred from direct tests of TRI

Binding Energies(MeV), Mirror Hypernuclei If isospin is an exact symmetry and therefore also no CSB, then theof mirror hypernuclei should be identical. Differences could be due to: - Coulomb effects + other electromagnetic effects - nuclear CSB -CSB