“fourth generation”: from b factories, to colliders and to the cosmos amarjit soni het, bnl...

“Fourth Generation”: From B Factories, to Colliders and to

the CosmosAmarjit SoniHET, BNL

EPS’11, Grenoble

EPS'11, Grenoble A. Soni 1

Outline

• Motivation• Hints• Implications for the High Intensity

Frontier• Implications for High Energy Frontier• DM possibilities• Summary & Outlook


Motivation• Seen 3; why not 4?• Enhanced prospects for DEWSB

• Enhanced prospects for baryogenesis

• NFC: built in• Cannot be just simple SM4: DM link?

• Readily accounts for B-CP-anomalies

4G2HDM:Bar-Shalom,Nandi,AS’11IMPLICATIONS


CAN NOT BE JUST SM4• Neutrino4 must be very heavy• 4G fermions very likely play important

role IN DEWSB -> likely a strongly coupled 4G

• Generic models [see Bar-Shalom, Nandi and A. S ‘11] suggest significant differences in search strategies from SM4



HINTS

Based on Enrico Lunghi+AS0707.0212; 0803.4340; 0903.5059;0912.0002

1010.6069

Delta K pi

•


Important to Examine only DeltaF=2 observables:Leave out Vub sin 2 β = 0.87+-.09{Lunghi+AS,hep-ph/08034340}

( became possible only due significantly reduced error in BK)

Gamiz et al;Becirevic;

Tantalo.

Antonio et al(RBC-UKQCD)

0702042

2.1-2.7 σ- deviation from the directly measured values of sin 2 β requires careful follow-up


Predict sin2β & fBEPS'11, Grenoble A. Soni 9

Inputs: S(Bd->ψK), εK, ΔMs, ΔMd, Vcb, γ

Predict: Br(B->τν) & fB


PHENO'11; 5/9/11 A. Soni 14

Mawhinney, plenary LAT’11

HUGE STRIDES IN LATTICE

CALCULATION OF BK!


In a nutshell• Bulk of NP effects is in Bd,Bs mixing &

in sin2β {CONFIRMS our 2008 findings}• Bulk of NP NOT in B->τν, or in εK

[Presence of subdominant effects therein certainly possible]

• Many, many checks for robustness of the conclusions

• VERY DIFFICULT to RECONCILE RESULTS with CKM-SM


Overall perspective• Sin 2 β from “penguin” dominated modes (ΦKS ,ηKS, …..) tends to be even smaller than from “gold-plated” mode• ΔACP (K π) = ACP (K+ π0) - ACP (K+ π -) is nowhere near zero (~14.4%) and rather difficult to

understand. . Also CDF, D0: S(ψΦ) mild indication….unsettled . D0, dimuon asymmetry exptal analysis extremely

difficult -> NEEDS confirmationImplications of our analysis is that such nonSM

effects requiring the presence of NP with a new CP-odd phase should persist


4G & BCP-anomalies

A.S. et al ‘10; Nandi & A.S’10;Buras et al’10; Hou & Ma’10



A. S et al 0807.1971; 1002.0595 {Note constraints from S,T, b -> s gamma,K-> pi nu nu ….are all included} C ALSO A.Buras et al 1002.2126


Predicted range of S(psiKs) in SM4 (with mt’=400 GeV) is (shown in red) comparedwith the experimentally measured value via the psi Ks mode (1 sigma error) and

with the SM (1 sigma)

SM4 seems to predict sin2 beta around 0.70 with an error of about 0.06;S. Nandi and A.S, 1011.6091

World Average


Recent D0 result is vertical axis and combined D0, CDF each For SM4 error on Delta_Gamma_s is increased

by a factor of two resulting in ~50% increase in a_sl^s

S.Nandi and A.S,1011.6091


Br(Bs->µµ): a very clean processIMPORTANT Correlation with S(psi phi)

SM4 may increase or decreaseBr by ~ O(3)

Current <3.60X10-8

CDF,HFAG

CDF UPDATE ‘11


Detection of 4G quarks[Atwood, Gupta, AS’11]

• An important feature: To a rather good approximation, pair production is

near threshold . Using this feature showed robust signals:

1)Single lepton2)Opposite sign leptons3) Same sign dileptonsAll 3 viable



Search for 4th generation at hadron colliders

An important caveat:• B-CP anomalies only need a

heavy top-like quark possessing akin to charged weak interactions: the underlying theory need not be simple SM4


4G2HDM:LEET for DEWSB[Bar-Shalom,Nandi, A.S ‘11]

• 2 Higgs doublet model for the 4th ; 2nd doublet with v2/v1 >> 1 couples only to 4th gen

• FCNC only among 3rd and 4th gen• Significant modifications to t’, b’ decays• t’->t h, b h+ very large BR, similarly for b’• Requires modification to search strategies


24 June, 2011 30

Phenomenology of type-I 4G2HDM

• FCNC effects only in t’ t & b’ b transitions

e.g.,

• Enhanced htt Yukawa interaction while suppressed ht’t’ one:

Bar-Shalom

24 June, 2011 BNL 31

t’ decay pattern

t’ decays:

Bar-Sahlom

24 June, 2011 BNL 32

b’ decay pattern

b’ decays:

Bar-Shalom

Summary & Outlook• 4G is well motivated for DEWB, baryogeneses,

alleviates B-CP anomalies & possibly dark matter connection.

Cannot be just simple SM4Heaviness of t’ may imply it may be strongly

coupledDecay pattern of t’, b’ may be quite different from

SM4



Urgent questions for experiments

• ATLAS,CMS: Φ, W’,Z’,G; t’, b’ exist?• LHCb [CDF,D0]: S(Bs->ψφ), as

sl ; adsl ;

S(Φ KS), AFB(K*ll) …….• BABAR,BELLE updates for ad

sl very useful• BELLE (UPS5S run and nearby): as

sl and linear combination

• BELLEII; SBF: S(η’KS, φKS, KSKSKS), Br(B->τν), ad

sl, assl (?); S(Bd(s)->K* γ; …);

S(D0); asl(D0)…

“fourth generation”: from b factories, to colliders and to the cosmos amarjit soni het, bnl...

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