高能物理实验发展方向-PowerPointPresen课件.pptx

1、Puzzles or new physics signal in B physics呂才典呂才典IHEP,Beijing CD Lu1nCurrent B physics experimentsnEnhancement of color suppressed modesnDirect CP asymmetry /AnnihilationnMixing induced CP asymmetry nPolarizations in BVV decaysnSummaryOutlineCD Lu2高能物理实验发展方向高能物理实验发展方向n更高能量更高能量：Tevatron,LHC，ILC，直直接对新粒

2、子，接对新粒子，新物理新物理的探索的探索n更高亮度更高亮度：B工厂，工厂，tau粲工厂等粲工厂等 精精确检验，间接确检验，间接新物理新物理的探索，更经济的探索，更经济n对超对称等对超对称等新物理模型的新物理模型的参数限制大多来源于参数限制大多来源于B物理实验物理实验n肖振军、杨亚东有很多研究肖振军、杨亚东有很多研究CD Lu3KEKSLACCurrent B factoriesBaBarPEPIIKEKBBelleCD Lu4B Factory ExperimentsnKEK,KEKB，e+8GeV,e 3.5GeVnBelle:700 Million B B-bar pairnSLAC,PE

3、P-II,e+9GeV,e 3.1GeVnBaBar:400 Million B B-bar pairnThey can reach branching ratios as small as 107 rare B decaysCD Lu5 d Vud Vus Vub d s =Vcd Vcs Vcb s b Vtd Vts Vtb b Unitarity Vud Vub*+Vcd Vcb*+Vtd Vtb*=0The triangles are measured mainly through non-leptonic B(bd)decaysFor example:by B,by BJ/K,K

4、VudVub*VtdVtb*by BK,BsK,VcdVcb*CD Lu6Current CKM measurements标准模型可以很好地解释目前的实验CD Lu7pCLEOCLEO实验组实验组(已降能区已降能区)pBelle KEKBelle KEK 和和 BaBarBaBar SLAC SLAC工作在工作在 B B 物理的能区物理的能区,现在正在取数现在正在取数.pTevatronTevatron实验室上也有很多实验室上也有很多BsBs的数据的数据p20072007年底即将运行的年底即将运行的LHC-bLHC-bp筹划中筹划中Super-BSuper-B.the size of CP v

5、iolation is not the size of CP violation is not big enough for cosmologybig enough for cosmologyp实验状况实验状况CD Lu8B pi pi decaysn Mode Exp pQCD(LO)NLObudbuddduu0CD Lu9B pi pi decaysnTree(T),color suppressed tree(C),penguin(P)CD Lu10Two operators contribute to decay:B0 0 B0 0 color enhanced color suppre

6、ssed C1 0.2 1/3 C2 1/3 bddbcdd0D0D)()(1dbcuO)()(2cbduO000DBcuuCD Lu11Isospin triangleD+(a1)D0+(a1+a2)D00(a2)Later experiments found much larger B0D0 pi0 branching ratiosCD Lu12For decay,these two diagrams do not cancel000DBD+(a1)D0+(a1+a2)D00(a2)47.02aarg(a2/a1)41CD Lu13Branching ratios of BD(*)mode

7、s Fac.APQCDEXP.D*+292527.62.1D+3027304D*0 01.02.81.70.5D0 0 0.72.52.90.5D*0+4853464D0+4854535PQCD:Keum et al,PRD69:094018,2004 a1=1.08a2=0.21for Fact.Approach(x 104)CD Lu14Direct CP violationcoscos21sinsin22rrrACP)()()()(BBBBACPCD Lu15Direct CP ViolationnRequire two kinds of decay amplitudes with:nD

8、ifferent weak phases (SM)nDifferent strong phases need hadronic calculation,usually non-perturbativeCD Lu16B,K Have Two Kinds of Diagrams with different weak phase b W u Tree VubVud*(s)B d(s)(K)W b t PenguinVtbVtd*(s)B O3,O4,O5,O6O1,O2(K)CD Lu17CD Lu18Strong phase is important for direct CPnBut usua

9、lly comes from non-perturbative dynamics,for exampleDKKKnFor B decay,perturbative dynamic may be more importantCD Lu19lXBubuCut quark diagram Sum over final-state hadronsnp,On-shellOff-shellhadronsInclusive DecayCD Lu20 pseudo-scalar B requires spins in opposite directions,namely,helicity conservati

10、on momentumBfermion flowspin(this configuration is not allowed)p1p2Annihilation suppression 1/mB 10%Like Be e For(V-A)(V-A),left-handed currentCD Lu21No suppression for O6nSpace-like penguinnBecome(s-p)(s+p)operator after Fiertz transformation Chirally enhancednNo suppression,contribution“big”(20-30

11、%)b)(sddud+(K+)CD Lu22Chiral EnhancementnTwo penguin operators:nO4(V-A)(V-A)nO6(V-A)(V+A)bsqqtRqqLbdOq6LqqLbdOq4R,L=15Fiertz trans.O(1)(S+P)(S-P)2mK2/(ms mB)CD Lu23CP Violation in B (K)(real prediction before exp.)CP(%)FABBNSPQCDExp+K+93+591759.71.2 0K+8 27 913 44.7 2.6+K 01.7 0.11 11.00.50.9 2.5+53

12、612+3010+387(2001)CD Lu24B K puzzlenK+-and K+0 differ by subleading amplitudes Pew and C.Their CP are expected to be similar.nTheir data differ by 5!A puzzle!ACP(K+pi)=(9.5 1.3)%ACP(K+pi)=(4.7 2.6)%CD Lu25Amplitude parametrization(C2/C4)(VusVub/VtsVtb)(1/2)(5/2)CD Lu26Direct CP violationT exp(i3)PT

13、exp(-i3)T exp(i3)PT exp(-i3)If T=0BrBr=BrIf T=0Br=BrDirect CPRecall sinsinCPACD Lu27Explanation 1nLarge K+-CP implies large T(predicted by PQCD in 2000)nLarge PEW to cancel its effect(Buras et al.;Yoshikawa)in K+0 0 new physics?T exp(i3)PT exp(-i3)PEWBr BrCD Lu28Explanation 2nOr large C to cancel it

14、s effect(Charng and Li;He and McKellar)in K+0)mechanism missed in SM calculation?(T+C)exp(i3)(T+C)exp(-i3)T exp(i3)PCD Lu29CD Lu30pMixing induced CP violationMixing induced CP violationCD Lu31Deviation from B J/psi KsCD Lu32CD Lu332007 resultCD Lu34CD Lu35Mixing Induced CPnB +,K,K,KKK nDominant by t

15、he B-B bar mixingnMost of the approaches give similar resultsnEven with final state interactionsCD Lu36For Example:(From Yossi Nir)CD Lu37Polarization of BVV decaysQCDF0.940.950.910.94CD Lu38nNew physics(Grossman;Yang et al.;Giri,Mohanta;Das et al.)nAnnihilation effect in QCDF(Kagan)nCharming pengui

16、n in SCET(Bauer et al)nRescattering effect(Colangelo et al.;Ladisa et al.;Cheng,Chua,Soni)nExotic b sg(Hou,Nagashima)Plausible resolutionsCD Lu39Previous pQCD RL=75%for B K*phi Too large Brs than exp.Implies too large form factorSo far,no data,except K*,control A0B()K*are governed by B()form factors

17、=A0 for B K*could be smaller?Choose the asymptotic models for the correspondingK*meson distribution amplitudes A0=0.28CD Lu40 Annihilation can enhance transverse contribution:RL=59%(exp:50%)and also right ratio of R=,R and right strong phase =,bsdsdLarge transverse component in BK*decaysK*H-n Li,Phy

18、s.Lett.B622,68,2005 CD Lu41Polarization of BVV decaysQCDF0.940.950.910.94New physics?CD Lu42New physics at TeVnPromising hypotheses that predict new elementary particles in the TeV scale(SUSY,extra-dimension,etc.)nMore ambitious proposals that incorporate flavor symmetries(and violation)to answer th

19、e deeper questions of flavor physics.New CP-violating phases and new interactions of quarks and leptons almost expectableCD Lu43New physics at TeVNew particles must come with New Flavor Mixing.Many models/hypotheses Experiments should decideCD Lu44SummarynThe current CP measurements are consistent with the standard model predictions.nAlthough there are still some puzzles nNew physics are still far away from us!?nLHC or Super B factories should answerCD Lu45Thank you!CD Lu46