高能物理实验发展方向-PowerPointPresen

PuzzlesornewphysicssignalinBphysics呂才典IHEP,Beijing

CDLu1CurrentBphysicsexperimentsEnhancementofcolorsuppressedmodesDirectCPasymmetry/AnnihilationMixinginducedCPasymmetryPolarizationsinBVVdecaysSummaryOutlineCDLu2高能物理实验发展方向更高能量：Tevatron,LHC，ILC，––直接对新粒子，新物理的探索更高亮度：B工厂，tau－粲工厂等––精确检验，间接新物理的探索，更经济对超对称等新物理模型的参数限制大多来源于B物理实验肖振军、杨亚东有很多研究CDLu3KEKSLACCurrentBfactoriesBaBarPEPIIKEKBBelleCDLu4BFactoryExperimentsKEK,KEKB，e+8GeV,e–3.5GeVBelle:700MillionBB-barpairSLAC,PEP-II,e+9GeV,e–3.1GeVBaBar:400MillionBB-barpairTheycanreachbranchingratiosassmallas10–7rareBdecaysCDLu5

d’VudVus

Vubds’=Vcd

Vcs

Vcbsb’VtdVts

VtbbUnitarityVudVub*+VcdVcb*+VtdVtb*=0Thetrianglesaremeasuredmainlythroughnon-leptonicB(bd)decaysForexample:α

byB→ππ,πρ,

α

β

byB→J/ψK,K

VudVub*

VtdVtb*

γ

byB→Kπ,Bs→Kρ,

γ

β

VcdVcb*CDLu6CurrentCKMmeasurements标准模型可以很好地解释目前的实验CDLu7CLEO实验组(已降能区)Belle@KEK

和BaBar@SLAC工作在B物理的能区,现在正在取数.Tevatron实验室上也有很多Bs的数据2007年底即将运行的LHC-b筹划中Super-B......

thesizeofCPviolationisnotbigenoughforcosmology实验状况CDLu8Bpipidecays

ModeExppQCD(LO)NLOdduuCDLu9BpipidecaysTree(T),colorsuppressedtree(C),penguin(P)CDLu10Twooperatorscontributeto

decay:

B0

0B0

0

colorenhanced

colorsuppressed

C1~–0.2~1/3C2~1/3

dduuCDLu11IsospintriangleD+

–(a1)D0

+(a1+a2)D0

0(a2)Laterexperimentsfoundmuch

larger

B0

D0pi0branchingratiosCDLu12For

decay,thesetwodiagramsdonotcancelD+

–(a1)D0

+(a1+a2)D0

0(a2)arg(a2/a1)~–41°CDLu13BranchingratiosofBD(*)

modesFac.APQCDEXP.D*+

–

292527.6±2.1D+

–

302730±4D*0

01.02.81.7±0.5D0

0

0.72.52.9±0.5D*0

+

485346±4D0

+

485453±5PQCD:Keumetal,PRD69:094018,2004

a1=1.08a2=0.21forFact.Approach(x10–4)CDLu14DirectCPviolationCDLu15DirectCPViolationRequiretwokindsofdecayamplitudeswith:Differentweakphases(SM)Differentstrongphases–needhadroniccalculation,usuallynon-perturbativeCDLu16B→

,

KHaveTwoKindsofDiagramswithdifferentweakphase

b

WuTree∝VubVud*(s)B

d(s)

(K)

W

b

tPenguin∝VtbVtd*(s)B

O3,O4,O5,O6O1,O2

(K)CDLu17CDLu18StrongphaseisimportantfordirectCPButusuallycomesfromnon-perturbativedynamics,forexampleDKK

K

ForBdecay,perturbativedynamicmaybemoreimportantCDLu19Cutquarkdiagram~Sumoverfinal-statehadrons~On-shellOff-shellhadronsInclusiveDecayCDLu20pseudo-scalarBrequiresspinsinoppositedirections,namely,helicityconservationmomentumBfermionflowspin(thisconfigurationisnotallowed)p1p2Annihilationsuppression~1/mB~

10%LikeBe

eFor(V-A)(V-A),left-handedcurrentCDLu21NosuppressionforO6Space-likepenguinBecome(s-p)(s+p)operatorafterFiertztransformationChirallyenhancedNosuppression,contribution“big”(20-30%)dud

+(K+)

–

CDLu22ChiralEnhancementTwopenguinoperators:O4~(V-A)(V-A)O6~(V-A)(V+A)

bsqtR,L=1

5Fiertztrans.O(1)(S+P)(S-P)2mK2/(msmB)CDLu23CPViolationinB

(K)

(realpredictionbeforeexp.)CP(%)FABBNSPQCDExp

+K–+9±3+5±9–17±5–9.7±1.2

0K++8±27±9–13±44.7±2.6

+K01.7±0.11±1–1.0±0.50.9

±2.5

+

––5±3–6±12+30±10+38±7(2001)CDLu24B

K

puzzleK+

-andK+

0differbysubleadingamplitudesPewandC.TheirCPareexpectedtobesimilar.Theirdatadifferby5

!Apuzzle!

ACP(K+pi–)=(–9.5

1.3)%ACP(K+pi–)=(4.7

2.6)%CDLu25Amplitudeparametrization(C2/C4)(VusVub/VtsVtb)»(1/

2)(

5/

2)»

CDLu26DirectCPviolationTexp(i

3)PTexp(-i

3)Texp(i

3)PTexp(-i

3)If

T=0BrBr=BrIf

T=0Br=BrDirectCPRecallCDLu27Explanation1LargeK+

-CPimplieslarge

T(predictedbyPQCDin2000)LargePEWtocancelitseffect(Burasetal.;Yoshikawa)inK+

0

newphysics?

Texp(i

3)PTexp(-i

3)PEWBr¼BrCDLu28Explanation2OrlargeCtocancelitseffect(CharngandLi;HeandMcKellar)inK+

0)mechanismmissedinSMcalculation?

(T+C)exp(i

3)(T+C)exp(-i

3)Texp(i3)PCDLu29CDLu30MixinginducedCPviolationCDLu31DeviationfromBJ/psiKsCDLu32CDLu332007resultCDLu34CDLu35MixingInducedCPB

+

–,

K,’K,KKK…DominantbytheB-BbarmixingMostoftheapproachesgivesimilarresultsEvenwithfinalstateinteractionsCDLu36ForExample:(FromYossiNir)CDLu37PolarizationofBVVdecaysQCDF0.940.950.910.94CDLu38Newphysics(Grossman;Yangetal.;Giri,Mohanta;Dasetal.)AnnihilationeffectinQCDF(Kagan)CharmingpenguininSCET(Baueretal)Rescatteringeffect(Colangeloetal.;Ladisaetal.;Cheng,Chua,Soni)Exoticb

sg(Hou,Nagashima)PlausibleresolutionsCDLu39PreviouspQCDRL=75%forBK*phi

ToolargeBrsthanexp.ImpliestoolargeformfactorSofar,nodata,except

K*,controlA0B

(

)K*aregovernedbyB

(

)formfactors=>A0forB

K*couldbesmaller?ChoosetheasymptoticmodelsforthecorrespondingK*mesondistributionamplitudes

A0=0.28CDLu40Annihilationcanenhancetransversecontribution:RL=59%(exp:50%)

andalsorightratioofR=,R

andrightstrongphase

=,

dsd

LargetransversecomponentinB

K*decaysK*H-nLi,Phys.Lett.B622,68,2005

CDLu41PolarizationofBVVdecaysQ