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Charge Symmetry Breaking/Isospin Nonconservation

Charge Symmetry Breaking/Isospin Nonconservation. Willem T.H. van Oers. ECT. June 13-17, 2005. Introduction Classification of N-N Forces Evidence for Class III Interactions Evidence for Class IV Interactions Time Reversal Invariance Charge Symmetry Breaking and Hypernuclei. System.

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Charge Symmetry Breaking/Isospin Nonconservation

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

  2. Introduction • Classification of N-N Forces • Evidence for Class III Interactions • Evidence for Class IV Interactions • Time Reversal Invariance • Charge Symmetry Breaking and Hypernuclei

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

  4. Hadron Multiplet Mass Splittings At the quark level: Hadron Valence Quarks Mass(MeV) (MeV) 497.648(22) +3.972(27) 493.677(16) 896.10(27) +4.44(37) 891.66(26) 1869.4(5) +4.78(10) 1864.6(5) 5279.4(0.5) -0.33(28) 5279.0(0.5) 939.56536(8) +1.2933317(5) 938.27203(8) 1197.449(30) +4.807(35) 1192.642(24) 1192.642(24) +3.27(8) 1189.37(7) 1321.31(13) +6.48(24) 1314.83(20)

  5. 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 No contribution from Coulomb repulsion Coulomb attraction !

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

  7. Gives isospin mixing of the neutral mesons Allows for G-parity violating decays Also predicts ! 0.05-0.10 ? possible experiments: Induced Drell-Yan processes at 30 GeV(FNAL, JPARC) i.e. compare i.e. or production in np collider i.e. i.e. implications for the G0 experiment:

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

  9. The Two-nucleon system and Isospin 1 0 -1 T 1 pp np nn 0 np space spin isospin np T=1 S A S A S S S S A np T=0 A 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

  10. Evidence for Class III Interactions 1) Low energy nucleon-nucleon scattering observables 2) Okamoto-Nolen-Schiffer effect: Binding energy differences of mirror nuclei

  11. Low Energy Nucleon-Nucleon Scattering Observables

  12. n-p Elastic Scattering Basic Principle of the CSB Experiments: CS Operation Rotation n p p p n n

  13. 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

  14. Neutron-proton magnetic interaction mixing Angular distribution similar to • Neutron-proton mass difference a affecting and exchange State dependent phase so s have different signs according J values

  15. Iqbal & Niskanen’s Prediction at 350 MeV

  16. by comparing the experimental results for With 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-odd coupling constant in terms of the strong coupling constant [95% C.L.] Note that the upper limit on the neutron edm gives but So comparable results! 2 new possibilities 1 measure in at 320 MeV with improved precision. 2 measure the attenuation of polarized proton through an aligned deuterium target

  17. 183 MeV 347 MeV (TRI violation) 477 MeV Take c from SAID FA95 solution: 183 MeV 347 MeV 477 MeV or (95% C.L.) neutron electric dipole moment gives an indirect limit of Considerably lower than the limits inferred from direct tests of TRI (dependent on !)

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

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