粒子物理学的对称性及其破缺.ppt

CD Lu * CP破坏的观测量 Phase is not physical quantity Not measurable No CP violation, if no interference CD Lu * Direct CP Violation CD Lu * Direct CP Violation Require two kinds of decay amplitudes with: Different weak phases (SM) Different strong phases – need hadronic calculation , usually non-perturbative CD Lu * B→? ?, ? K have two kinds of diagrams with different weak phase b W u Tree ∝ VubVud*(s) B ? d(s) ? (K) W b t Penguin∝VtbVtd* (s) B ? O3,O4,O5,O6 O1,O2 ? (K) CD Lu * Strong phase is important for direct CP But usually comes from non-perturbative dynamics, for example D K K ? K ? For B decay, perturbative dynamic may be more important CD Lu * Non-leptonic B decays: Study of CP violation – mixing-induced and direct CP violation CKM angle measurement: ?, ?, ? Test of standard model Signal of new physics … … CD Lu * Picture of PQCD Approach hard interaction inside the dotted line 4-quark operator b (5.3GeV) CD Lu * strong phase in short distance When the Wilson coefficients calculated to next-to-leading order, the vertex corrections can give strong phase CD Lu * Cut quark diagram ~ Sum over final-state hadrons ~ On-shell Off-shell hadrons Inclusive Decay CD Lu * CP Violation in B? ? ? (K)(real prediction before exp.) CP(%) FA BBNS PQCD Exp ? +K – +9±3 +5±9 –17±5 –11.5±1.8 ? +K 0 1.7± 0.1 1 ±1 –1.0±0.5 –2 ±4 ? 0K + +8 ± 2 7 ±9 –13 ±4 +4 ± 4 ? +? – –5±3 –6±12 +30±10 +37±10 (2001) (2004) CD Lu * New physics at TeV Promising hypotheses that predict new elementary particles in the TeV scale (SUSY, extra-dimension, etc.) More ambitious proposals that incorporate flavor symmetries (and violation) to answer the deeper questions of flavor physics. New CP-violating phases and new interactions of quarks and leptons