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Theoretical Overview of B Physics personal perspectives Xin-Qiang Li Central China Normal University Talk given at HFCPV-2018, Zhengzhou, 2018/10/26
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Page 1: Theoretical Overview of B Physics personal perspectives · ag.unibe.ch/, and av.web.cern.ch/] 160 175 190 205 220 235 250 = + + = + = MeV ETM 09D ETM 11A ALPHA 11 ETM 12B ALPHA 12A

Theoretical Overview of B Physics

→ personal perspectives ←

Xin-Qiang Li

Central China Normal University

Talk given at HFCPV-2018, Zhengzhou, 2018/10/26

Page 2: Theoretical Overview of B Physics personal perspectives · ag.unibe.ch/, and av.web.cern.ch/] 160 175 190 205 220 235 250 = + + = + = MeV ETM 09D ETM 11A ALPHA 11 ETM 12B ALPHA 12A

Outline

Introduction

Theoretical tools for B physics

B − B mixings: ∆Ms,d, ∆Γs,d, as,dfs

Bs,d → µ+µ−: powerful model killing

Semi-leptonic decays: |Vub|, |Vcb| and R(D(∗))

Exclusive b→ s`+`− decays: several anomalies

Non-leptonic decays: higher-order pert. corrs

Conclusion

2 / 35

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Why B physics:

I What is B physics: properties, productions and decays of vari-ous hadrons containing at least one bottom quark;

Bu,d,s,c mesons, Λb baryon

I Why study B physics: three main motivations;

3 / 35

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Dedicated B-physics experiments:

I Past: first observation of B → Xsγ by CLEO in 1994; continued by Tevatron @

Fermilab and the two B-factories: BaBar @ SLAC and Belle @ KEK with many key

measurements; [A. J. Bevan et al., “The Physics of the B Factories,” 1406.6311]

I Current: dedicated LHCb (also ATLAS and CMS) @ LHC with many exciting

results; [I. Bediaga et al., “Physics case for an LHCb Upgrade II - Opportunities

in flavour physics, and beyond, in the HL-LHC era,” arXiv:1808.08865]

I Future: besides LHCb @ LHC, also Belle II @ SuperKEKB expected to start

data taking in 2018, designed to find NP beyond the SM of particle physics;

[https://confluence.desy.de/display/BI/B2TiP+WebHome; 1808.10567]

assl

±3.0 × 10 4

±10.0 × 10 4

±33.0 × 10 4

[ ]±0.35

±1.5

±1.5

±5.4

s [mrad]

±22

±4

±14

±49

A

±1.0 × 10 5

±35.0 × 10 5

±4.3 × 10 5

±28.0 × 10 5

Current

HL-LHC

2025

LHCb

LHCb

ATLAS/CMS

Belle II

RK [%]±0.70

±3.6

±2.2

±10.0

R(D * ) [%]±0.20

±0.50

±0.72

±2.6

(B0 + )(B0

s+ ) [%]

±21

±10

±34

±90

Current

HL-LHC

2025

LHCb

LHCb

ATLAS/CMS

Belle II

4 / 35

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Theoretical tasks for B physics:

I Main task: try to improve the theory predictions to match the more

and more precise exp. data;

I Many dynamical frameworks developed: HQET, SCET, NRQCD,

QCDF, pQCD, · · · ↪→ based on QCD, and separate pert. from non-

pert. strong interaction effects ↔ factorization theorem;

I For the non-pert. objects: mostly from Lattice QCD and LCSR,· · · ; [for reviews see: http://flag.unibe.ch/, and https://hflav.web.cern.ch/]

160 175 190 205 220 235 250

=+

+=

+=

MeV

ETM 09DETM 11AALPHA 11ETM 12BALPHA 12AETM 13B, 13CALPHA 13ALPHA 14

FLAG average for =

HPQCD 09FNAL/MILC 11HPQCD 12 / 11AHPQCD 12RBC/UKQCD 13A (stat. err. only)RBC/UKQCD 14ARBC/UKQCD 142RBC/UKQCD 141

FLAG average for = +

HPQCD 13ETM 13E

FLAG average for = + +

5 / 35

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Current status of B physics:

I The CKM mechanism of flavor & CP violation well established! ↪→2008 Nobel Prize for Kobayashi and Maskawa;

I Information on UT from tree- and loop-level processes well consistent!

6 / 35

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Current status of B physics:

I Remember: O(20%) NP contributions to most FCNC processes still

allowed by the current data;

I Several intriguing tensions/anomalies do observed in flavour physics,

might be any BSM signals?

Br(B->pi^0 pi^0)A_CP(B->pi K)

Z.Ligeti,1606.02756

† all of them not yet conclu-sive: theo. uncertaintiesor exp. fluctuations?

† except for theo. cleanestmodes, more cross-checksneeded;

† exp. measurements of re-lated observables needed;

† indep. theory and latticecalculations needed;

7 / 35

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How to describe B-hadron weak decays:

I At the quark level: B-hadron weak decays mediated by weakcharged-current Jµcc coupled to W±;

Lcc = −g2√

2Jµcc W

†µ + h.c., Jµcc = (uL, cL, tL) γµ VCKM

dLsLbL

↪→ VCKM: describes flavor violation, and very predictive, especially for CPV!

I In the real world: no free quarks due to confinement; quarksalways confined inside hadrons through soft-gluon exchanges;

↪→ In B physics, simple weak decays overshadowed by complex strong interactions!

8 / 35

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Typical features for B-hadron weak decays:

I A typical multi-scale problem and scales are highly hierarchical;

EW interaction scale � ext. mom’a in B rest frame � QCD-bound state effectsmW ∼ 80.4 GeV � mb ∼ 4.8 GeV � ΛQCD ∼ 1 GeV

I Starting point Leff : integrate out heavy d.o.f. (mW,Z,t � mb), physics

above (below) µ ∼ mb contained in Ci (〈Oi〉); [A. J. Buras, 1102.5650]

I Ci: RG-improved pert. calculable;

matching at µ0 and running to µb;

NNLL accuracy available!9 / 35

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Hadronic matrix elements for B-hadron weak decays:

I How to evaluate 〈f |Oi|B〉: 〈0|Oi|B〉, 〈π|Oi|B〉, 〈ππ|Oi|B〉, 〈B|Oi|B〉,· · · ;

I 〈M1M2|Oi|B〉: not yet possible in lattice QCD; expressed in terms of (few)

universal non-pert. hadronic quantities with pert. calculable coefficients;

- dynamical approaches based on factorization theorems: PQCD, QCDF,

SCET, · · · ; [Keum, Li, Sanda, Lu, Yang ’00;

Beneke, Buchalla, Neubert, Sachrajda, ’00;

Bauer, Flemming, Pirjol, Stewart, ’01]

- (approximate) symmetries of QCD: Isospin, U-Spin, V-Spin, and flavor

SU(3) symmetries, · · · ; [Zeppenfeld, ’81;

London, Gronau, Rosner, Chiang, Cheng et al.]10 / 35

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B − B mixings:

I Motivation: strongly suppressed in SM; highly sensitive to BSM effects;

↪→ Λ ≥ 103 TeV

I ∆Ms,d.= 2|M s,d

12 |: calculated from box diagrams with internal virtual par-

ticles; main uncertainty from Bag parameters 〈Bq |Oi|Bq〉 ∝ f2BqB

(i)Bq

;

∆MSMd = (0.53+0.03

−0.04) ps−1

∆MHFAGd = (0.5065± 0.0019) ps−1

∆MSMs = (18.1+1.1

−1.2) ps−1

∆MHFAGs = (17.757± 0.021) ps−1

[Kirk, Lenz and Rauh, 1711.02100;

T. Rauh, talk given at CKM2018]11 / 35

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B − B mixings:

I ∆Γs,d.= 2|Γs,d12 | cosφs,d12 : arise from absorptive part of box diagrams, dom-

inated by tree-level b→ ccs(d) transitions; [Artuso/Borissov/Lenz, 1511.09466]

Γs12 =Λ3

m3b

[Γs,(0)3 +

αs

4πΓs,(1)3 +

(αs4π

)2Γs,(2)3 + ...

]+

Λ4

m4b

(Γs,(0)4 + ...

)+ ... [H. M. Asatrian et al, 1709.02160]

b s

s b

c

cSecond OPE = Heavy Quark Expansion (HQE)

I as,dfs.=

∣∣∣ Γs,d12

Ms,d12

∣∣∣ sinφs,d12 : motivated by 2013 D0 dimuon charge asymmetry!

-0.4 -0.2 -0.0 0.2 0.4φ ccss [rad]

0.06

0.08

0.10

0.12

0.14

∆Γs[p

s−1]

ATLAS 19.2 fb−1

D0 8 fb−1

CMS 19.7 fb−1

CDF 9.6 fb−1Combined

LHCb 3 fb−1

SM

68% CL contours(∆ log L = 1.15)

HFLAVPDG 2018

)0(BSLA-0.02 -0.01 0 0.01 0.02

) s0(B

SL

A

-0.02

-0.01

0

0.01

HFLAVPDG 2018

B factoryaverage

LHCbXµ(*)

(s) D→ 0(s)B

0DXµ(*)

(s) D→ 0(s)B

0Dmuons

0Daverage

10×Theory

World average

= 12χ∆

12 / 35

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B − B mixing:

I ∆Ms,d vs ∆Γs,d: state-of-the-art comparison; [Kirk, Lenz and

Rauh, 1711.02100; T. Rauh, talk given at CKM2018]

I SM predictions and exp. averages consistent with each other!

↪→ Large NP effect in Bs,d mixings now closed!

13 / 35

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Bs,d → µ+µ−:

I Facts about Bs,d → µ+µ−: highly suppressed within the SM;

- helicity suppressed, by a factor of (mµ/mB)2;

- FCNC process, forbidden at tree-level, proceed

only via loop diagrams;

- CKM suppressed by |VtbV ∗ts|2;

↪→ very sensitive to NP, especially from OS(P );

I Theory status: CA now to NNLO QCD + NLO EW; enhanced EM correction

included; [Bobeth et al., 1311.0903; Beneke, Bobeth and Szafron, 1708.09152]

Heff = −GF α√2πs2W

[VtbV

∗tq

A,S,P∑i

(CiOi + C′iO′i

)+ h.c.

]OA = (qγµPLb) (¯γµγ5`) , OS(P ) = mb(qPRb) [¯(γ5)`]

B(Bs → µ+µ−) = (3.57± 0.17)× 10−9, B(Bd → µ+µ−) = (1.06± 0.09)× 10−10

14 / 35

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Bs,d → µ+µ−:

I CMS + LHCb and LHCb updated results: [1411.4413, 1703.05747]

B(Bs → µ+µ−) = (3.0 ±0.6+0.3−0.2) · 10−9 (7.8σ);

B(Bd → µ+µ−) = (3.9+1.6−1.4) ·

10−10 (3.0σ);

)−µ+µ → 0s

BF(B0 2 4 6 8

9−10×

)− µ+ µ

→ 0B

F(B

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.99−10×

68.27%

95.45%

99.73%

99.99%

SM

LHCb

I Powerful in model killing: good consistency between SM and exp. data;

[D. Straub, 1205.6094]

15 / 35

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Bs,d → µ+µ−:

I Time-dependent observables: due to sizeable ∆Γs; [De Bruyn et

al., 1204.1737; Fleischer et al., 1703.10160; 1709.04735]

I With the updated LHC: these observables provide new d.o.f. for NP

searches; [Fleischer, Jaarsma, Tetlalmatzi-Xolocotzi, 1703.10160; 1709.04735]

16 / 35

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|Vub| and |Vcb| problem:

I Importance of |Vxb|: play a key role in determining the apex of UT;

- |Vub| or |Vub/Vcb| constraints

drectly the UT;

- b→ s induced FCNC processes∝|VtbV ∗ts|2 ' |Vcb|2

[1 +O(λ2)

];

- εK ' x|Vcb|2 + · · · ;

↪→ More precise determination of

|Vxb| is of utmost importance!

I Incl. vs excl. methods: [Nandi, Gambino, Tackmann, talks at CKM 2016]

- Inclusive |Vcb|: OPE/HQE, dominated by theory uncertainties, especially by

correlations of theoretical parameters;

- Inclusive |Vub|: OPE/HQE, limited knowledge of leading and subleading SFs;

- Exclusive |Vxb|: how precise can the form factors be calculated by LQCD or LCSR;

17 / 35

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|Vub| and |Vcb| problem:

I Status of global fit for |Vxb|: [Gambino, Silva, Bona, talks at CKM2018]

I Results for CKM2018: [Silva, Bona, talks at CKM2018]

|Vcb|incl. = (42.2± 0.4± 0.6) · 10−3, |Vub|incl. = (4.44± 0.17± 0.31) · 10−3

|Vcb|excl. = (41.2± 0.6± 0.9± 0.2) · 10−3, |Vub|excl. = (3.72± 0.09± 0.22) · 10−3

↪→ |Vxb| tension significantly reduced, especially for |Vcb|!

↪→ global fit favours |Vub|excl. & |Vcb|incl.!18 / 35

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R(D) and R(D∗) anomalies:

I B → D(∗)τ ν decays: tree-level processes;massive τ makes them sensitive

to tree-level NP like RH currents, charged Higgs, leptoquarks, · · · ;

I Current status: R(D(∗)) =Br(B→D(∗)τντ )

Br(B→D(∗)`ν`); [BaBar, 1205.5442, 1303.0571;

Belle, 1507.03233, 1607.07923, 1612.00529; LHCb, 1506.08614, 1708.08856]

0.2 0.3 0.4 0.5 0.6R(D)

0.2

0.25

0.3

0.35

0.4

0.45

0.5

R(D

*) BaBar, PRL109,101802(2012)Belle, PRD92,072014(2015)LHCb, PRL115,111803(2015)Belle, PRD94,072007(2016)Belle, PRL118,211801(2017)LHCb, PRL120,171802(2018)Average

Average of SM predictions

= 1.0 contours2χ∆

0.003±R(D) = 0.299 0.005±R(D*) = 0.258

HFLAV

Summer 2018

) = 74%2χP(

σ4

σ2

HFLAVSummer 2018

. R(D)SM = 0.299± 0.003 2.3σ

[0.407± 0.039± 0.024]

. R(D∗)SM = 0.258± 0.005 3.0σ

[0.306± 0.013± 0.007]

↪→ combined ∼ 3.78σ deviation!

I Theo.: more precise lattice calculations for B → D(∗) FFs at non-zero recoil!

I Exp.: AD(∗)

λ , RD∗

L , Λb → Λcτ ν, Bs → D(∗)s τ ν, Bc → J/Ψ(ηc)τ ν, B → Xcτ ν;

19 / 35

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R(D) and R(D∗) anomalies:I Importance of other observables: [Celis, Jung, Li, Pich, 1612.07757]

I Bc-lifetime constraint: [Li/Yang/Zhang, 1605.09308; Hu/Li/Yang, 1810.04939]

LSMEFT = L(4)SM +

1

Λ2

∑i

Ci(Λ)Qi,

Q(3)lq = (lγµτ

I l)(qγµτIq), Q(1)lequ = (lje)εjk(qku)

Qledq = (lje)(dqj), Q(3)lequ = (ljσµνe)εjk(qkσµνu)

↪→ V −A and/or tensor Lorentz structure needed!

20 / 35

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R(D) and R(D∗) anomalies:

I The observed tension is model independent: exclusive alreadyover-saturates inclusive; [M. Freytsis, Z. Ligeti, J. Ruderman, 1506.08896]

B The data on R(D) and R(D∗) imply:

Br(B → D∗τ ν) + Br(B → Dτν) = (2.78± 0.25)%

B Including the four lightest orbitally excited D meson states:

Br(B → D(∗)τ ν) + Br(B → D∗∗τ ν) ∼ 3%

B From inclusive=∑

exclusive: Br(b→ Xcτ ν) = (2.35± 0.23)% (LEP)

I R(Xc) constraint: [Kamali/Rashed/Datta,1801.08259; Lai/Li/Li/Yang, w.i.p.]

-2.0 -1.5 -1.0 -0.5 0.0

0.15

0.20

0.25

0.30

0.35

gL

R(Xc)

-0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.50.15

0.20

0.25

0.30

gT

R(Xc)

21 / 35

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R(D) and R(D∗) anomalies:

I Another hint of LFUV: around 1.7σ above SM; [LHCb, 1711.05623;

Cohen/Lamm/Lebed, 1807.02730; Wang/Zhu, 1808.10830]

R(J/ψ) =Br(Bc → J/ψτντ )

Br(Bc → J/ψ`ν`)= 0.71± 0.17± 0.18 vs 0.20 ∼ 0.39 (theo.)

I Future prospects with Belle-II and LHCb very promising![Albrecht

et al., 1709.10308; I. Bediaga et al., 1808.08865]

3 23 50 300Integrated Luminosity [fb−1]

0.001

0.01

0.1

Ab

solu

teσR

(X)

LHCb

X = D∗, τ− → µ−νµντX = D∗, τ− → π−π+π−ντ

X = J/ψ, τ− → µ−νµντ

R(D)

R(D

*)

0.3 0.35 0.4 0.450.24

0.26

0.28

0.3

0.32

0.34

LHCb Belle II

Future WA SM predictionSM

σ1

σ3

σ5

σ7

σ9

-18fb

-122fb

-150fb

-15ab-150ab

I Maybe the first tantalizing hint for BSM? Let’s stay tuned!22 / 35

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Exclusive b→ s`+`− decays:

I Heff for b→ s`+`−: [Bobeth, Gambino, Gorbahn, Haisch, hep-ph/0312090]

Hb→seff = −4GF√

2VtbV

∗ts

∑i

(CiOi + C′iO′i

), O(′)

7 =e

16π2mb(sσµνPR(L)b

)Fµν

O(′)9 =

e2

16π2

(sγµPL(R)b

) (¯γµ`

)O(′)

10 =e2

16π2

(sγµPL(R)b

) (¯γµγ5`

)I Amplitudes for exclusive decays: [Descotes-Genon, talk at FPCP 2016;

Bobeth, Chrzaszcz, Dyk, and Virto, arXiv:1707.07305]

B M

ℓ+

ℓ−

O7,7′

B M

ℓ+

ℓ−

O9,10,9′,10′...

2

B M

ℓ+

ℓ−

O7,7′

B M

ℓ+

ℓ−

O9,10,9′,10′...

2

B M

ℓ+

ℓ−

Oi

cc

3

A(`)L,Rλ = N (`)

λ

{(C

(`)9 ∓C

(`)10 )Fλ(q2)+

2mbMB

q2

[C

(`)7 F

Tλ (q2)−16π2MB

mbHλ(q2)

]}23 / 35

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Exclusive b→ s`+`− decays:I Hadronic matrix elements of Oi: [Beneke/Feldmann/Seidel, 0106067,

0412400; Grinstein/Pirjol, hep-ph/0404250; Beylich/Buchalla/Feldmann, 1101.5118]

† Large recoil (low-q2)

- very low-q2 (≤ 1 GeV2)

dominated by O7;

- low-q2 ([1, 6] GeV2)

dominated by O9,10;

- QCDF or SCET, LCSR;

† Small recoil (high-q2) - dominated by O9,10; - local OPE + HQET;

I Key issues: how large of power corrs from b→ scc→ s`+`− for q2 ≤ 6 GeV2

and from fact. FF terms? [Descotes-Genon et al., 1510.04239]

24 / 35

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Exclusive b→ s`+`− decays:I Parametrisation of Hλ(q2): [Khodjamirian et al., 1006.4945; Bobeth et

al., 1707.07305;]

AL,Rλ = Nλ{

(C9 ∓ C10)Fλ(q2) +2mbMB

q2

[C7FTλ (q2)− 16π2MB

mbHλ(q2)

]}

Hλ(z) =1− z z∗

J/ψ

z − zJ/ψ

1− z z∗ψ(2S)

z − zψ(2S)

Hλ(z), Hλ(z) =[ K∑k=0

α(λ)k zk

]Fλ(z)

z(q2) ≡√t+ − q2 −

√t+ − t0√

t+ − q2 +√t+ − t0

I Based on analyticity + data and valid for −7 ≤ q2 ≤ m2ψ(2S)

: [Bobeth et al.,

1707.07305; Chrzaszcz et al., 1805.06378; Mauri et al., 1805.06401]

NP9C Re

3− 2− 1− 0 1

NP

10C

Re

1.5−

1−

0.5−

0

0.5

1

1.5

2

2.5

99% CLLHCb Run2

]-1LHCb Upgrade [50 fb

]-1LHCb Phase 2 [300 fb

]-1BelleII [50 ab

25 / 35

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Exclusive b→ s`+`− decays:I Observed anomalies: [Dettori, Langenbruch, talks at Moriond 2018]

]4c/2 [GeV2q0 5 10 15

5'P

1−

0.5−

0

0.5

1

(1S)

ψ/J

(2S)

ψ

LHCb data

Belle data

ATLAS data

CMS dataSM from DHMVSM from ASZB

]4c/2 [GeV2q

0 5 10 15 20

KR

0

0.5

1

1.5

2

SM

LHCbLHCb

LHCb BaBar Belle

PRL 113, 151601 (2014)

0 1 2 3 4 5 6

q2 [GeV2/c4]

0.0

0.2

0.4

0.6

0.8

1.0

RK

∗0

LHCb

LHCb

BIP

CDHMV

EOS

flav.io

JC

]4c/2 [GeV2q5 10 15

]4

c­2

GeV

­8 [

10

2q

)/d

µµ

φ→

s0B

dB

( 0

1

2

3

4

5

6

7

8

9LHCb

SM pred.

Data

I Comments: 1, P ′5 stat. fluctuation unlikely; 2, precise evaluation of QED effect in

R(∗)K very necessary; 3, cross-checks about hadronic nuisance parameters needed;

26 / 35

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Exclusive b→ s`+`− decays:

I Global fits to b→ s`+`− data: [Danny van Dyk, talk at CKM2018]

I Conclusion: while different in the treatment of local and non-local hadronic contri-

butions, all groups agree on a negative shift to C9 by −1.1...−1.76 ' −25...40%

of the SM value, although other contributions are also possible.

27 / 35

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Exclusive b→ s`+`− decays:I New global fits: [Capdevila et al., 1704.05340; D. Straub, talk at CKM2018]

I New directions for model builders: [G. Isodro, talk at CKM2018]

28 / 35

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Non-leptonic B decays:I To leading power in the heavy-quark expansion, 〈M1M2|Oi|B〉 obeys the follow-

ing factorization formula: [Beneke, Buchalla, Neubert, Sachrajda, ’99-’04]

〈M1M2|Oi|B〉 ' m2B F

BM1+ (0) fM2

∫du T Ii (u) φM2

(u) + (M1 ↔M2)

+ fB fM1 fM2

∫dωdvdu T IIi (ω, v, u) φB(ω) φM1 (v) φM2 (u)

+O(1/mb)

Oi (μ)

+ O(1/M )W

i (μ)C

μ ∼ m> b

π +

π-

0Bi=1...10

π +0B

π-

C i (μ)i,j=1...10

π-

0B

Ojfact(μ)

T (μ)ijI

jfact(μ)Q

T (μ)ijII+

μ m b<

+ O(1/m )b

π+

I Systematic framework to all orders in αs, but limited accuracy by 1/mb corrs.29 / 35

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Non-leptonic B decays:

I Status of the hard kernels T I,II : [Bell/Beneke/Huber/Li, from ’09]

I Missing NNLO pieces: 2-loop tree with insertion of penguin operators Q3−6;

2-loop penguin with insertion of penguin operators Q3−6; work in progress!30 / 35

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Non-leptonic B decays:

I How to deal with power corrections of order O(1/mb);

I New insights from collider-physics applications like collinear anomaly/rapidity di-

vergence? [Becher/Neubert ’10; Becher/Bell ’11; Chiu/Jain/Neill/Rothstein ’12]

↪→ our next task: how to evaluate the power corrections?31 / 35

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Non-leptonic B decays:I Tree-dominated decays: Brs [×10−6] [Beneke, Huber, Li ’09]

I Theory II: small λB and form-factor hypothesis are more favoured;

I Colour-allowed modes well described, but colour-suppressed modes less;32 / 35

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Non-leptonic B decays:I Penguin-dominated decays: ACP [×10−2] [Bell, Beneke, Huber, Li ’15]

I “NLO” and “NNLO”: including only pert. calculable SD contribution;

I “NNLO+LD”: power-suppressed spectator and annihilation terms included back;

I For πK, NNLO change minor, since the total penguin αc4 = ac4 + rπχac6 + βc3;

I NNLO correction does not help resolving the observed πK CP asymmetry puzzle;

33 / 35

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Non-leptonic B decays:I Brs and ratios: 10−3 (b→ cud), 10−4 (b→ cus) [Huber, Krankl, Li ’16]

I For Bd decays, NNLO Brs higher than the data; for Λb decays, NNLO Brs smaller

than the data; ↪→ non-negligible power corrections with natural size ∼ 10−15%?34 / 35

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Conclusion and outlook

I High-luminosity frontier is very complementary to high-energy fron-

tier, especially for NP searches;

I Great progress achieved in both theo. and exp. sides for B physics,

and also a very promising future (LHCb and Belle II, · · · );

I CKM mechanism of flavor and CP violation well established. How-

ever, 20% NP effects in most FCNC processes often possible;

I Several deviations observed at 2 ∼ 4σ in b → cτ ν and b → sµµ

decays, implications of LFUV? Lets stay tuned!

I QCDF at leading power and at NNLO in QCD established and almost

complete. Any further breakthroughs welcome;

Thank You for Your Attention!35 / 35