Introduction to Charge Symmetry Breaking

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Introduction to Charge Symmetry Breaking. Introduction What do we know? Remarks on computing cross sections for 0 production. G. A. Miller, UW. Charge Symmetry: QCD if m d =m u , L invariant under u $ d. Isospin invariance [H,T i ]=0, charge independence, CS does NOT imply CI. - PowerPoint PPT Presentation


  • Introduction to Charge Symmetry BreakingIntroductionWhat do we know?Remarks on computing cross sections for 0 productionG. A. Miller, UW

  • Charge Symmetry: QCD if md=mu, L invariant under u$ dIsospin invariance [H,Ti]=0, charge independence, CS does NOT imply CI

  • Example- CS holds, charge dependent strong forcem(+)>m(0) , electromagneticcauses charge dependence of 1S0 scattering lengths no isospin mixing

  • Example:CIB is not CSBCI ! (pd! 3He0)/(pd ! 3H+)=1/2NOT related by CSIsospin CG gives 1/2deviation caused by isospin mixingnear threshold- strong N! N contributes, not ! mixing

  • Example proton, neutron proton (u,u,d) neutron (d,d,u)mp=938.3, mn=939.6 MeVIf mp=mn, CS, mpmp(mp-mn)Coul 0.8 MeV>0md-mu>0.8 +1.3 MeV

  • Miller,Nefkens, Slaus 1990

  • All CSB arises from md>mu & electromagnetic effects Miller, Nefkens, Slaus, 1990All CIB (that is not CSB) is dominated by fundamental electromagnetism (?)CSB studies quark effects in hadronic and nuclear physics

  • Importance of md-mu >0, p, H stable, heavy nuclei existtoo large, mn >mp + Binding energy, bound ns decay, no heavy nucleitoo large, Delta world: m(++)
  • Importance of md-mu >0, influences extraction of sin2Wfrom neutrino-nucleus scattering

    0, to extract strangeness form factors of nucleon from parity violating electron scattering

  • Outline of remaindercomments on pn! d0dd!4He0Old stuff- NN scattering, nuclear binding energy differences

  • NN force classification-Henley Miller 1977 Coulomb: VC(1,2)=(e2/4r12)[1+(3(1)+3(2))+3(1)3(2)]I: ISOSCALAR : a +b 12II: maintain CS, violate CI, charge dep.3(1)3(2) = 1(pp,nn) or -1 (pn)III: break CS AND CI: (3(1)+3(2))IV: mixes isospin

  • VIV(3(1)-3(2))(3(1)-3(2)) |T=0,Tz=0i=2|T=1,Tz=0i isospin mixingVIV=e(3(1)-3(2))((1)-(2))L +f((1)(2))3 ((1)(2)) Lmagnetic force between p and n is Class IV, current of moving proton ints with n mag momentspin flip 3P0!1 P0 TRIUMF, IUCF expts

  • md-muCLASS III:Miller, Nefkens, Slaus 1990meson exchange vs EFT?

  • Search for class IV forces A -see next slide

  • Where is EFT?ant

  • A=3 binding energy differenceB(3He)-B(3H)=764 keVElectromagnetic effects-model independent, Friar trick use measure form factors EM= 693 20 keV, missing 70verified in three body calcsCoon-Barrett - mixing NN, good a, get 80 10 keVMachleidt- Muther TPEP-CSB, good a get 80 keVgood a get 80 keV

  • Summary of NN CSBmeson exchangeWhere is EFT?

  • old strong int. calc.

  • np! d0Theory Requirementsreproduce angular distribution of strong cross section, magnitudeuse csb mechanisms consistent with NN csb, cib and N csb, cib, Gardestig talk

  • Gardestig, Nogga, Fonseca, van Kolck, Horowitz, Hanhart , Niskanenplane wave, simple wave function, = 23 pb 14pbBacher

  • Initial state interactionsInitial state OPEP, + HUGE, need to cancel Nogga, Fonseca

  • plane wave, Gaussian w.f. photon in NNLO, LO not included23 pb vs 14 pbet al

  • Initial state LO dipole exchanged*(T=1,L=1,S=1), d*d OAM=0, emission makes dd component of He, estimate using Gaussian wf 3P0

  • Theory requirements: dd!4He0start with good strong, csb np! d0 good wave functions, initial state interactions-strong and electromagneticgreat starts have been made

  • Suggested plans: dd!4He0Stage I: Publish existing calculations, Nogga, Fonseca, Gardestig talks, HUGE LO photon exchange absent now, no need to reproduce datapresent results in terms of input parameters, do exercises w. paramsStage II: include LO photon exchange, Fonseca

  • Much to do, lets do as much as possible here