quark flavour observables in 331 models in the flavour precision era

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1 Quark flavour observables in 331 models in the flavour precision era Fulvia De Fazio INFN- Bari • 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 JHEP 1302 (2013) 023 EPS HEP 2013 Stockholm

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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 - PowerPoint PPT Presentation

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Page 1: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Quark flavour observables in 331 models in the flavour precision era

Fulvia De FazioINFN- Bari

• the flavour precision era• a NP scenario to look at flavour observables: 331 model• conclusions

Based onA.J. Buras, J. Girrbach, M.V. Carlucci,FDF

JHEP 1302 (2013) 023

EPS HEP 2013 Stockholm

Page 2: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Flavour Precision Era (FPE): working assumptions

• CKM parameters have been determined by means of tree-level decays• Non-perturbative parameters are affected by very small uncertainties and fixed

Two scenarios

1. |Vub| fixed to the exclusive (smaller) value2. |Vub| fixed to the inclusive (larger) value

Using g 68° :

|Vub| in scenario 1 |Vub| in scenario 2 requires NP enhancing B(B t nt) no NP required for B(B t nt) reproduces the experimental value for SJ/yKs SJ/yKs higher than experimentsuppresses eK w.r.t. experiment eK consistent with experiment

DMs,d agree within uncertainties, slightly preferring models predicting a small suppression

Page 3: Quark  flavour  observables in 331 models  in the  flavour  precision era

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331 Model: general features

Gauge group: SU(3)C X SU(3)L X U(1)X

Spontaneously broken to SU(3)C X SU(2)L X U(1)X

Spontaneously broken to SU(3)C X U(1)QNice

features:• requirement of anomaly cancelation + asympotic freedom of QCD implies

number of generations= number of colors• two quark generations transform as triplets under SU(3)L , one as an antitriplet

this may allow to understand why top mass is so large

Fundamental relation: XTTQ 83

Key parameter: defines the variant of the model

=13 (331 variant)• leads to interesting phenomenology• new gauge bosons have integer charges

P. Frampton, PRL 69 (92) 2889F. Pisano & V. Pleitez, PRD 46 (92) 410

Page 4: Quark  flavour  observables in 331 models  in the  flavour  precision era

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331 Model: new particle content

New Gauge Bosons

ZVV

Y

00 ,

Singly charged

Neutral

Neutral

Mediates tree level FCNC in the quark sector(couplings to leptons are universal)

Extended Higgs sector Three SU(3)L triplets, one sextet

New heavy fermions D,S new heavy quarks with Q=-1/3

T new heavy quark with Q=2/3

El new heavy neutrinos (both L & R)

Page 5: Quark  flavour  observables in 331 models  in the  flavour  precision era

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331 Model: quark mixing

Quark mass eigenstates defined upon rotation through two unitary matrices UL & VL

In contrast to SM only one of them can be traded for VCKM, the other one enters in Z’ couplings to quarks

Page 6: Quark  flavour  observables in 331 models  in the  flavour  precision era

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331 Model: Z’ couplings to quarksThe case of Bd,Bs,K systems

depend only on four new parameters:

stringent correlations between observables expected

Bd system only on s13 and d1

Bs system only on s23 and d2

K system on s13 , s23 and d2 - d1

FCNC involve onlyleft-handed quarks

We fix 1MZ’ 3 TeV

Page 7: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Oases in the parameter space from DF=2 observables

Imposing the experimental constraints:

One finds the allowed oases for the parameters s13 , s23 >0 & 0<d23<2p 0<d13<2p

Example of NP contribution: The case of Bd mixing

DMs

Mass difference in the B̅s –Bs system

Syf CP asymmetry in

Bs J/y f

DMd

Mass difference in the B̅d –Bd system

SyKs

CP asymmetry in Bd J/y Ks

Page 8: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Oases in the parameter space from DF=2 observables

A1

A3

A2

A4

A1

B1

B3B4

B2

Small oases in Bs case can be eliminated by data on the mixing phase and on eK

Other observables should be considered to find the optimal oasis

Blue regions Syf

Red ones DMs

Blue regions SyKs Red ones DMd

Page 9: Quark  flavour  observables in 331 models  in the  flavour  precision era

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The decay Bs m+ m-

SM effective hamiltonian one master function Y0(xt)

Z’ contribution modifies this function to:

a new phase

independent on the decaying meson and on the lepton flavour

Theoretically clean observable:

the new phase involved

LHCb 1211.2674 SM

phase of the function S entering in the box diagramvanishes in SM

Analogous observables can be considered in the Bd case

Page 10: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Searching for the optimal oasis

A1,B3

A1,B1

A3,B3

A3,B1 B1 B3

From both Bs and Bd systems

Observables in Bd system

Page 11: Quark  flavour  observables in 331 models  in the  flavour  precision era

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Searching for the optimal oasis

A3

A1

Triple correlation in Bs system

Test of the model: Once the sign of Ss

m+m- is determined the model uniquely predicts the correlation between Syf and B(Bs m+m-)

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Correlations with eK

It is possible to reproduce DMs, DMd and find eK consistent with experiment

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Conclusions

• Dominant NP contributions in 331 model come from tree-level Z’ exchanges

• The model can remove the tensions between SM and experiment when 1 TeV MZ’ 3 TeV

• The parameters of the model reproduce DF=2 observables in restricted oases

• The optimal oasis can be selected looking at other obervables and correlations among them

• A triple correlation in the Bs system has been identified as a valuable test of the model

• Increasing the mass of Z’ it is still possible to find oases where the DF=2 constraints are OK however some observables receive very small NP contributions (rare decays)