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Quark flavour observables in 331 models in the flavour precision era . Fulvia De Fazio INFN- Bari. EPS HEP 2013 Stockholm. the flavour precision era a NP scenario to look at flavour observables : 331 model conclusions. Based on A.J. Buras , J. Girrbach , M.V. Carlucci,FDF
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Quark flavour observables in 331 models in the flavour precision era Fulvia De Fazio INFN- Bari EPS HEP 2013 Stockholm • the flavourprecision era • a NP scenario to look at flavourobservables: 331 model • conclusions Based on A.J.Buras, J. Girrbach, M.V. Carlucci,FDF JHEP 1302 (2013) 023
FlavourPrecision Era (FPE): working assumptions • CKM parametershavebeendeterminedbymeansoftree-leveldecays • Non-perturbativeparameters are affectedbyverysmalluncertainties and fixed Two scenarios |Vub| fixedto the exclusive (smaller) value |Vub| fixedto the inclusive (larger) value Usingg 68° : |Vub| in scenario 1 |Vub| in scenario 2 requires NP enhancing B(B tnt) no NP requiredforB(B tnt) reproduces the experimentalvalueforSJ/yKs SJ/yKshigherthanexperiment suppresseseKw.r.t.experimenteKconsistentwithexperiment DMs,dagreewithinuncertainties, slightlypreferringmodelspredicting a smallsuppression
P. Frampton, PRL 69 (92) 2889 F. Pisano & V. Pleitez, PRD 46 (92) 410 331 Model: general features Gaugegroup: SU(3)C X SU(3)L X U(1)X SpontaneouslybrokentoSU(3)C X SU(2)L X U(1)X SpontaneouslybrokentoSU(3)C X U(1)Q Nice features: • requirementofanomalycancelation + asympoticfreedomof QCD implies • numberofgenerations=numberofcolors • two quark generationstransformastriplets under SU(3)L , oneasanantitriplet • thismayallowtounderstandwhy top mass is so large Fundamental relation: • Key parameter: defines the variantof the model • b=13 (331 variant) • leadstointerestingphenomenology • newgaugebosonshaveintegercharges
331 Model: new particle content Singlycharged New GaugeBosons Neutral Neutral Mediatestreelevel FCNC in the quark sector (couplingstoleptons are universal) ExtendedHiggssector Three SU(3)Ltriplets, onesextet D,S newheavyquarkswith Q=-1/3 Tnewheavy quark with Q=2/3 Elnewheavyneutrinos (both L & R) New heavyfermions
331 Model: quark mixing Quark mass eigenstatesdefinedupon rotation throughtwounitarymatricesUL& VL In contrastto SM onlyoneofthem can betradedfor VCKM, the otheroneenters in Z’ couplingstoquarks
331 Model: Z’ couplings to quarks The case of Bd,Bs,K systems dependonly on fournewparameters: FCNC involve only left-handedquarks Bd system only on s13 and d1 Bs system only on s23 and d2 K system on s13 , s23 and d2 - d1 stringentcorrelationsbetweenobservablesexpected Wefix1MZ’ 3 TeV
Oases in the parameter space from DF=2 observables DMd Mass difference in the B̅d–Bd system SyKs CP asymmetry in BdJ/ Ks DMs Mass difference in the B̅s–Bs system Syf CP asymmetry in BsJ/ f Exampleof NP contribution: The case ofBd mixing Imposing the experimentalconstraints: Onefinds the allowedoasesfor the parameters s13 , s23 >0 & 0<d23<2p 0<d13<2p
Oases in the parameter space from DF=2 observables A3 A4 B3 B4 B1 B2 A2 A1 A1 Blueregions SKs Red ones DMd Blueregions Sf Red ones DMs Smalloases in Bs case can beeliminatedby data on the mixing phase and on eK Otherobservablesshouldbeconsideredtofind the optimaloasis
The decay Bsm+m- SMeffectivehamiltonian one master function Y0(xt) independent on the decayingmeson and on the leptonflavour Z’contributionmodifiesthisfunctionto: a newphase Theoretically cleanobservable: phaseof the function S entering in the box diagram vanishes in SM the newphaseinvolved LHCb 1211.2674 SM Analogousobservables can beconsidered in the Bd case
Searching for the optimal oasis A1,B3 A3,B3 A1,B1 A3,B1 B1 B3 FrombothBs and Bdsystems Observables in Bd system
Searching for the optimal oasis Triple correlation in Bs system A3 A1 Test of the model: Once the signofSsm+m- isdetermined the modeluniquelypredicts the correlationbetweenSyf and B(Bsm+m-)
Correlations with eK ItispossibletoreproduceDMs, DMd and findeKconsistentwithexperiment
Conclusions • Dominant NP contributions in 331 model come fromtree-level Z’ exchanges • The model can remove the tensionsbetween SM and experiment • when 1 TeV MZ’ 3 TeV • The parametersof the modelreproduceDF=2 observables in restrictedoases • The optimaloasis can beselectedlooking at otherobervables and correlationsamongthem • A triple correlation in the Bs system hasbeenidentifiedas a valuable test of the model • Increasing the mass of Z’ itisstillpossibletofindoaseswhere the DF=2 constraints are OK • however some observablesreceiveverysmall NP contributions (rare decays)