CKM * physics at hadron colliders Mat Charles (Sorbonne - - PowerPoint PPT Presentation

SLIDE 1

CKM* physics at hadron colliders

Mat Charles (Sorbonne Université/LPNHE) representing the LHCb collaboration

1

v4 * meaning here: flavour physics that lets us make serious, indirect tests of the SM either by itself or in combination with other measurements

SLIDE 2

Quick reminder of the players

• At the Tevatron (pp): D0 & CDF
• 1.96 TeV CM
• At the LHC (pp): ATLAS, CMS & LHCb
• 2010 and 2011: 7 TeV CM
• 2012: 8 TeV CM
• 2015-2018: 13 TeV CM
• LHCb usually runs at a much lower luminosity/pile-up

than ATLAS & CMS

• LHCb recorded about 3 fb−1 in Run1 (2010-2012)


and so far about 51/2 fb−1 in Run2 (2015-2018)

• ATLAS/CMS recorded about 26 fb−1 in Run1


and so far about 137 fb−1 in Run2

2

Caution: Run2 numbers are probably already out of date

SLIDE 3

Back in 2016...

• Barack Obama was the US president
• France hadn't won the world cup in a generation
• There were only 14 films in the Marvel Cinematic Universe
• And at CKM, the overview talk covered:

3

• CP viola*on in the interference between B-meson

mixing and decay

• CP viola*on in B-meson mixing
• B-meson width and mass differences
• Photon polarisa*on in Bsàφγ
• Tree-level determina*on of γ
• Searches for CP viola*on in b baryons
• Measurement of |Vub / Vcb|
• Leptonic and charmless hadronic rare decays
• Angular analysis of B0àK*µ+µ decays
• Lepton Flavour Universality tests

2 Vincenzo Vagnoni, CKM 2016

• What* have we learned since then?

* in CKM physics

SLIDE 4

The classic Unitarity Triangle

• Disclaimer: will use 𝛽,𝛾,𝛿 notation (rather than 𝜚2,1,3)
• Before BABAR & Belle, hoped for O(1) BSM effects
• Today: triumph of CKM picture
• Focus instead on over-constraining the triangle, looking for

pieces that don't fit.

• Requires many careful, precise measurements.

4

γ γ

K

ε

K

ε α α

d

m ∆

s

m ∆ &

d

m ∆

ub

V β sin 2

(excl. at CL > 0.95) < 0 β

• sol. w/ cos 2

e x c l u d e d a t C L > . 9 5

α β γ

ρ

• 1.0
• 0.5

0.0 0.5 1.0 1.5 2.0

η

• 1.5
• 1.0
• 0.5

0.0 0.5 1.0 1.5

excluded area has CL > 0.95 ICHEP 16

CKM

f i t t e r

ρ

• 1
• 0.5

0.5 1

η

• 1
• 0.5

0.5 1 γ

β α

s

m Δ

d

m Δ

d

m Δ

K

ε

cb

V

ub

V ) ν τ → BR(B

summer16

http://www.utfit.org/UTfit/ http://ckmfitter.in2p3.fr/

Fits from summer

• 2016. Hopefully it'll

be time for an update soon! See talks on Thursday morning [WG4/5].

SLIDE 5

The classic Unitarity Triangle

• On LHCb side:
• Many incremental improvements on 𝛿
• Constraints on 𝛾
• Also results from B-factories, notably on 𝛾 -- see next talk!
• Let's walk through new LHCb inputs, starting with 𝛿...

5

γ γ

K

ε

K

ε α α

d

m ∆

s

m ∆ &

d

m ∆

ub

V β sin 2

(excl. at CL > 0.95) < 0 β

• sol. w/ cos 2

e x c l u d e d a t C L > . 9 5

α β γ

ρ

• 1.0
• 0.5

0.0 0.5 1.0 1.5 2.0

η

• 1.5
• 1.0
• 0.5

0.0 0.5 1.0 1.5

excluded area has CL > 0.95 ICHEP 16

CKM

f i t t e r

ρ

• 1
• 0.5

0.5 1

η

• 1
• 0.5

0.5 1 γ

β α

s

m Δ

d

m Δ

d

m Δ

K

ε

cb

V

ub

V ) ν τ → BR(B

summer16

Fits from summer

• 2016. Hopefully it'll

be time for an update soon! See talks on Thursday morning [WG4/5].

http://www.utfit.org/UTfit/ http://ckmfitter.in2p3.fr/

SLIDE 6

𝛿

• Can make tree-level measurements of 𝛿 from interference
• f b → c (Vcb) and b → u (Vub) decays
• Use two-step decays, often:
• B → D0 X, D0 → f
• B → D0 X, D0 → f
• Many choices for X, f...

6

γ = arg [− VudV*

ub

VcdV*

cb ]

B X D0 X D0 f

D → f D → f

Vcb Vub

• Aside: loop-level measurements of 𝛿 also possible (see

talks on Tuesday morning, WG 5)

SLIDE 7

𝛿

• No single dominant mode.
• Game instead is to make many individual measurements,

combine them. Recent LHCb combination:

7

LHCb-CONF-2018-002

B decay D decay Method Ref. Dataset

†

Status since last combination [3] B+ → DK+ D → h+h GLW [14] Run 1 & 2 Minor update B+ → DK+ D → h+h ADS [15] Run 1 As before B+ → DK+ D → h+ππ+π GLW/ADS [15] Run 1 As before B+ → DK+ D → h+hπ0 GLW/ADS [16] Run 1 As before B+ → DK+ D → K0

Sh+h

GGSZ [17] Run 1 As before B+ → DK+ D → K0

Sh+h

GGSZ [18] Run 2 New B+ → DK+ D → K0

SK+π

GLS [19] Run 1 As before B+ → D⇤K+ D → h+h GLW [14] Run 1 & 2 Minor update B+ → DK⇤+ D → h+h GLW/ADS [20] Run 1 & 2 Updated results B+ → DK⇤+ D → h+ππ+π GLW/ADS [20] Run 1 & 2 New B+ → DK+π+π D → h+h GLW/ADS [21] Run 1 As before B0 → DK⇤0 D → K+π ADS [22] Run 1 As before B0 → DK+π D → h+h GLW-Dalitz [23] Run 1 As before B0 → DK⇤0 D → K0

Sπ+π

GGSZ [24] Run 1 As before B0

s → D⌥ s K±

D+

s → h+hπ+

TD [25] Run 1 Updated results B0 → D⌥π± D+ → K+ππ+ TD [26] Run 1 New

† 1

("last combination" = April 2017)

PLB 777 (2018) 16 PLB 760 (2016) 117 PRD 91, 112014 (2015) JHEP 10 (2014) 097 arXiv:1806.01202 PLB 733C (2014) 36 JHEP 11 (2017) 156 PRD 92, 112005 (2015) PRD 90, 112002 (2014) PRD 93, 112018 (2016) JHEP 08 (2016) 137 JHEP 03 (2018) 059 JHEP 06 (2018) 084

• Won't go through them individually, but just to illustrate...

SLIDE 8

]

4

/c

2

) [GeV

+

π

S

K (

2

m

1 2 3

]

4

/c

2

) [GeV

−

π

S

K (

2

m

1 2 3

LHCb

𝛿 from B+ → D K+, D → KS h+ h−

• GGSZ method, using CLEO-c input for phase variation across

Dalitz plot (a.k.a. "model-independent")

• LHCb Run2 data (2015+2016):


Combined with prior Run1 result:

8

arXiv:1806.01202

γ = (87+11

−12) ∘

γ = (80+10

−9 ) ∘

]

4

/c

2

) [GeV

−

π

S

K (

2

m

1 2 3

]

4

/c

2

) [GeV

+

π

S

K (

2

m

1 2 3

LHCb

B+ → DK+ B+ → DK−

+

x

+

y

0.2 − 0.1 − 0.1 0.2 0.2 − 0.1 − 0.1 0.2

Run 1 2015 & 2016 data Combined result

LHCb

contours hold 68%, 95% CL

−

x

−

y

0.2 − 0.1 − 0.1 0.2 0.2 − 0.1 − 0.1 0.2

Run 1 2015 & 2016 data Combined result

LHCb

contours hold 68%, 95% CL

Good agreement between Run1 and Run2 results.

With infinite apologies to the London Palladium

SLIDE 9

LHCb 𝛿 combination

• We are used to saying "𝛿, the least-well-known angle of the

CKM triangle".

• ... but uncertainties on 𝛽 around 5°, depending on statistical
• treatment. Being overtaken by 𝛿!

9

0.2 0.4 0.6 0.8 1

CL − 1

50 100 150

] ° [ γ

68.3% 95.5%

LHCb

Preliminary

decays

s

B decays B decays

+

B Combination

LHCb-CONF-2018-002

γ = (74.0 +5.0

5.8)

e.g. HFLAV average: α = (84.9+5.1

−4.5) ∘

Preliminary

40 50 60 70 80 90 100 110

)

• (

γ

2013 2014 2015 2016 2017 2018 2019

LHCb

Preliminary

SLIDE 10

𝛾 from B0 → J/𝜔 KS, B0 → 𝜔(2S) KS

• Classic time-dependent CPV measurement, golden mode for

the B-factories.

• This analysis: J/𝜔 → e+e−, 𝜔(2S) → 𝜈+𝜈− with Run1
• ... since J/𝜔 → 𝜈+𝜈− done previously, PRL 115, 031601 (2015)

10

A[cc]K0

S(t) ≡ Γ(B0(t)→[cc]K0 S) − Γ(B0(t)→[cc]K0 S)

Γ(B0(t)→[cc]K0

S) + Γ(B0(t)→[cc]K0 S)

= S sin(∆m t) − C cos(∆m t) cosh(∆Γ t/2) + A∆Γ sinh(∆Γ t/2) ≈ S sin(∆m t) − C cos(∆m t)

C: CPV in direct decay (expect 0) S=sin2𝛾: CPV in interference

(taking ∆Γ=0)

JHEP 11 (2017) 170

m(J/ψK0

S) [MeV/c2]

5200 5300 5400 5500 5600

Candidates / (4.5 MeV/c2)

10 102 103

B0 → J/ψK0

S

B0

s → J/ψK0

S

• Comb. background

LHCb

m(ψ(2S)K0

S) [MeV/c2]

5200 5250 5300 5350 5400 5450

Candidates / (2.5 MeV/c2)

10 102 103

B0 → ψ(2S)K0

S

B0

s → ψ(2S)K0

S

• Comb. background

LHCb

J/ψ K0

S

ψ(2S) K0

S

Run1

SLIDE 11

𝛾 from B0 → J/𝜔 KS, B0 → 𝜔(2S) KS

• Flavour tagging needed to measure TD asymmetry
• Opposite-side (muon; electron; kaon; charges of all tracks; charm)
• Same-side (pion; proton)
• Event-by-event mistag estimate (𝜃)


calibrated with control channels to


• btain mistag probability (𝜕)
• B+ → J/𝜔 K+ for OS, B0 → J/𝜔 K*0 for SS
• Simultaneous fit, sharing ∆m, 𝜐 but not CP observables.

11

Tagger B0 → J/ψK0

S

B0 → ψ(2S)K0

S

OS 3.60(13) 2.46(5) SS 2.40(28) 1.07(8) OS + SS 5.93(29) 3.42(9)

Effective tagging efficiencies (%)

Decay time [ps]

5 10 15

Signal yield asymmetry

• 0.2

0.2

LHCb

B0 → J/ψK0

S

Decay time [ps]

5 10 15

Signal yield asymmetry

• 0.2

0.2

LHCb

B0 → ψ(2S)K0

S

JHEP 11 (2017) 170 Run1 Run1

SLIDE 12

𝛾 from B0 → J/𝜔 KS, B0 → 𝜔(2S) KS

• New modes!
• Still not as precise as BaBar+Belle, but

getting there (and more data on tape).

• Compare HFLAV average of charmonium

modes: S = 0.699 ± 0.017

12

C

• B0 → J/ψK0

S

• =

0.12 ± 0.07 ± 0.02 S

• B0 → J/ψK0

S

• =

0.83 ± 0.08 ± 0.01 C

• B0 → ψ(2S)K0

S

• = − 0.05 ± 0.10 ± 0.01

S

• B0 → ψ(2S)K0

S

• =

0.84 ± 0.10 ± 0.01

This Run1 result, JHEP 11 (2017) 170

C(B0 → J/ψ K0

S) = − 0.038 ± 0.032

S(B0 → J/ψ K0

S) =

0.73 ± 0.04

• Prev. result, PRL 115, 031601 (2015)

(using J/𝜔 → 𝜈+𝜈− decay mode, Run1)

S C

0.5 0.6 0.7 0.8 0.9 1

• 0.2

0.2 0.4

B0 → ψ(2S)K0

S

B0 → J/ψ(e+e−)K0

S

B0 → J/ψ(µ+µ−)K0

S

Combination

LHCb

CL for the inner (outer) contour is 39% (87%)

C(B0 → [cc]K0

S) = −0.017 ± 0.029 ,

S(B0 → [cc]K0

S) =

0.760 ± 0.034 ,

SLIDE 13

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

13

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

SLIDE 14

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

14

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

B0 → π+ π− Constraints on 𝛽 I-spin

Gronau & London, PRL 65, 3381 (1990)

B0 → π0 π0 B+ → π+ π0

SLIDE 15

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

15

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

Bs → K+ K− B0 → π+ π− Constraints on 𝛾, 𝛿

Fleischer, PLB 459 (1999) 306 Fleischer, EPJC 52 (2007) 267

U-spin

SLIDE 16

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

16

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

Bs → K+ K− B0 → π+ π− Constraints on 𝛾, 𝛿 I-spin

Ciuchini et al, JHEP 10 (2012) 29

B0 → π0 π0 B+ → π+ π0 U-spin

SLIDE 17

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

17

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

Constraints on 𝜚s

Fleischer et al, PRD 94, 113014 (2016),
 JHEP 1703 (2017) 055

B0 → π− l+ νl Bs → K− l+ νl Bs → K+ K− B0 → π+ π− U-spin 𝛿

SLIDE 18

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

18

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

Validity test of SM

He, EPJC 9 (1999) 443 Lipkin, PLB 621 (2005) 126

Bs → π+ K− B0 → K+ π− B(Bs → π+ K−) B(B0 → K+ π−) 𝜐(B0)/𝜐(Bs)

SLIDE 19

B(s) → h+ h′−

• Measurements from LHCb of
• Time-dependent CP asymmetries in B0 → π+ π−:
• Time-dependent CP asymmetries in Bs → K+ K−:
• Time-integrated CP asymmetries in B0 → K+ π−:
• Time-integrated CP asymmetries in Bs → π+ K−:

19

PRD 98, 032004 (2018) Cπ+π−, Sπ+π−

CK+K−, SK+K−, AΔΓ

K+K−

AB0

CP

AB0

s

CP

Cπ+π− = −0.34 ± 0.06 ± 0.01, Sπ+π− = −0.63 ± 0.05 ± 0.01, CK+K− = 0.20 ± 0.06 ± 0.02, SK+K− = 0.18 ± 0.06 ± 0.02, A∆Γ

K+K−

= −0.79 ± 0.07 ± 0.10, AB0

CP

= −0.084 ± 0.004 ± 0.003, AB0

s

CP

= 0.213 ± 0.015 ± 0.007,

Validity test:
 ∆ = −0.11 ± 0.04 ± 0.03,
 consistent w/ SM (zero)

SLIDE 20

𝜚s

• Classic mode Bs → J/𝜔 𝜚: no LHCb update since last CKM.

20

• Several measurements

at the Tevatron and the LHC

• World average

– φs = −30 ± 33 mrad

• S*ll compa*ble with the

SM at the present level

• f precision

φs from b→ccs transi6ons

7

Vincenzo Vagnoni, CKM 2016

• However...

SLIDE 21

𝜚s in Bs → J/𝜔 K+ K− above the 𝜚

• Angular analysis; 5D fit to


(decay time, mKK, 3 helicity angles)

• Separate data into two regions and fit simultaneously:
• "low-mass" (near-𝜚): mKK < 1050 MeV
• "high-mass": mKK > 1050 MeV
• To avoid correlation with previous analysis, float physics

parameters (𝜚s, |𝜇|, Γs, ∆Γs) separately in each region

• ... but share resonance parameters etc

21

θJ/ψ µ+µ− K+K− θKK y χ x z K− µ− µ+ B0

s

K+

Yields / (15 MeV)

200 400 600 800 1000 1200 1400 1600 1800 2000

LHCb

[GeV]

K

+

K

m

1 1.5 2 5 − 5

−

data Fit (1020) φ S-wave (1525)

2

f' (1680) φ (1270)

2

f (1750)

2

f (1950)

2

f

JHEP 08 (2017) 037 Run1 Run1

SLIDE 22

𝜚s in Bs → J/𝜔 K+ K− above the 𝜚

22

JHEP 08 (2017) 037

φs = 119 ± 107 ± 34 mrad, |λ| = 0.994 ± 0.018 ± 0.006, Γs = 0.650 ± 0.006 ± 0.004 ps1, ∆Γs = 0.066 ± 0.018 ± 0.010 ps1.

• Results from this analysis:

φs = −25 ± 45 ± 8 mrad, |λ| = 0.978 ± 0.013 ± 0.003, Γs = 0.6588 ± 0.0022 ± 0.0015 ps1, ∆Γs = 0.0813 ± 0.0073 ± 0.0036 ps1.

• Combine with prev. analysis (𝜚 region):
• Combine with Bs → J/𝜔 π+ π−: (Γs and ∆Γs unchanged)

ϕs = 1 ± 37 mrad |λ| = 0.973 ± 0.013

Run1

• And then another mode...

All very SM.

SLIDE 23

800 1000 1200 1400 1600

]

2

c ) [MeV/

−

π

+

K ( m

800 900 1000 1100 1200 1300 1400 1500 1600

]

2

c ) [MeV/

+

π

−

K ( m

2 4 6 8 10 12 14 16 18 20

Weighted candidates

LHCb

• oo in Bs → (K+ π−)(π+ K−)

23

ϕd ¯

d s

B0

s ¯ b s ¯ s d ¯ d s

K∗0 ¯ K∗0

¯ u, ¯ c, ¯ t

• In general, 𝜚s depends on the decay mode.
• Loop-dominated => sensitive to NP

.

• This analysis: 750 < mKπ < 1600 MeV
• Scalar, vector, tensor resonances included
• Upper limit chosen to avoid D0 → Kπ
• Previous analyses just looked at the K*(890)
• Time-dependent & flavour-tagged analysis
• Key results of amplitude fit:
• Polarisations, relative contributions of


resonances
 measured.

5000 5200 5400 5600 5800

]

2

c ) [MeV/

+

π

−

K

−

π

+

K ( m

200 400 600 800 1000 1200

)

2

c Candidates / ( 8 MeV/

)

+

π

−

K )(

−

π

+

K ( →

s

B )

+

π

−

K )(

−

π

+

K ( → B )

+

K

−

K )(

−

π

+

K ( → B )

+

π

−

π )(

−

π

+

K ( → B )

+

K

−

K )(

−

π

+

K ( →

s

B )

+

π

−

K )(

−

π p ( →

b

Λ Partially reconstructed Combinatorial Total Model Data

LHCb

Tagging algorithm ✏tag [%] ✏eff [%] SS 62.0 ± 0.7 1.63 ± 0.21 OS 37.1 ± 0.7 3.70 ± 0.21 Combination 75.6 ± 0.6 5.15 ± 0.14

Common parameters φdd

s [rad]

−0.10 ± 0.13 ± 0.14 |λ| 1.035 ± 0.034 ± 0.089

JHEP 03 (2018) 140 Run1

SLIDE 24

𝜚s overall

24

ϕc¯

cs s

= − 0.021 ± 0.031 HFLAV average:

Exp. Mode Dataset φccs

s

∆Γs (ps−1) Ref. CDF J/ψφ 9.6 fb−1 [−0.60, +0.12], 68% CL +0.068 ± 0.026 ± 0.009 [2] D0 J/ψφ 8.0 fb−1 −0.55+0.38

−0.36

+0.163+0.065

−0.064

[3] ATLAS J/ψφ 4.9 fb−1 +0.12 ± 0.25 ± 0.05 +0.053 ± 0.021 ± 0.010 [4] ATLAS J/ψφ 14.3 fb−1 −0.110 ± 0.082 ± 0.042 +0.101 ± 0.013 ± 0.007 [5] ATLAS above 2 combined −0.090 ± 0.078 ± 0.041 +0.085 ± 0.011 ± 0.007 [5] CMS J/ψφ 19.7 fb−1 −0.075 ± 0.097 ± 0.031 +0.095 ± 0.013 ± 0.007 [6] LHCb J/ψK+K− 3.0 fb−1 −0.058 ± 0.049 ± 0.006 +0.0805 ± 0.0091 ± 0.0032 [7] LHCb J/ψπ+π− 3.0 fb−1 +0.070 ± 0.068 ± 0.008 — [8] LHCb J/ψK+K−a 3.0 fb−1 +0.119 ± 0.107 ± 0.034 +0.066 ± 0.018 ± 0.010 [9] LHCb above 3 combined +0.001 ± 0.037(tot) +0.0813 ± 0.0073 ± 0.0036 [9] LHCb ψ(2S)φ 3.0 fb−1 +0.23+0.29

−0.28 ± 0.02

+0.066+0.41

−0.44 ± 0.007

[10] LHCb D+

s D− s

3.0 fb−1 +0.02 ± 0.17 ± 0.02 — [11] All combined −0.021 ± 0.031 +0.085 ± 0.006

a m(K+K−) > 1.05 GeV /c2.

Inputs

SLIDE 25

CPV in baryon decays

• Direct CPV expected in b baryons just like b mesons.
• ... but no 5𝜏 observation so far. Evidence reported at

CKM 2016 in 𝛭b → p π− π+ π−:

25

New avenues: search for CP viola6on in Λb→pπ−π+π− decays from LHCb

• CP viola*on has never been
• bserved in the decays of any

baryonic par*cle

• Λb→pπ−π+π− decays used to

search for CP-viola*ng asymmetries in triple products

• f final-state par*cle momenta

17 CP-viola*ng observable

LHCb-PAPER-2016-030 arXiv:1609.05216 ~6600 events

Vincenzo Vagnoni, CKM 2016

New avenues: search for CP viola6on in Λb→pπ−π+π− decays from LHCb

• Local CP-viola*ng effects

studied as a func*on of the the rela*ve orienta*on between the decay planes formed by the pπ− and the π+π− systems (Φ)

• An evidence for CP viola*on at

the 3.3σ level is found

• This represents the first

evidence of CP viola*on in the baryon sector

18

Asymmetry [%] LHCb-PAPER-2016-030 arXiv:1609.05216

• What's new since then?

Nature Physics 13, 391(2017)

SLIDE 26

CPV in baryon decays?

26

JHEP 08 (2018) 039

Searches in other 4-body decays: no evidence.

Λ0

b → pK−π+π−

Λ0

b → pK−K+K−

Ξ0

b → pK−K−π+

a b

T-odd P

(%) −0.60 ± 0.84 ± 0.31 −1.56 ± 1.51 ± 0.32 −3.04 ± 5.19 ± 0.36 a b

T-odd CP

(%) −0.81 ± 0.84 ± 0.31 1.12 ± 1.51 ± 0.32 −3.58 ± 5.19 ± 0.36

]

2

c ) [GeV/

−

π

+

π

−

pK ( m

5.2 5.4 5.6 5.8 6

)

2

c Candidates/(9 MeV/

200 400 600 800 1000 1200 1400 >0)

T

C (

b

Λ

Full fit

−

π

+

π

−

pK →

b

Λ

• Comb. bkg.

Part-rec. bkg.

+

π

−

π

−

π

+

K → B

−

π

+

K

−

pK →

b

Λ

−

π

+

π

−

pK →

b

Ξ

−

π

+

π

−

π p →

b

Λ

+

π

−

π

+

K

−

K →

s

B

LHCb

Example mass plots:

]

2

c ) [GeV/

−

K

+

K

−

pK ( m

5.2 5.4 5.6 5.8 6

)

2

c Candidates/(9 MeV/

50 100 150 200 250 300 350 400 450 >0)

T

C (

b

Λ

Full fit

−

K

+

K

−

pK →

b

Λ

• Comb. bkg.

−

π

+

K

−

pK →

b

Λ

−

K

+

K

−

pK →

b

Ξ

−

π

+

K

+

K

−

K → B

−

K

+

K

−

K

+

K →

s

B

LHCb

]

2

c ) [GeV/

−

K

−

K

+

π p ( m

5.7 5.8 5.9 6 6.1

)

2

c Candidates/(9 MeV/

10 20 30 40 50 60 70 80 90 >0)

T

C (

b

Ξ

Full fit

−

K

−

K

+

π p →

b

Ξ

• Comb. bkg.

−

π

+

π

−

pK →

b

Λ

−

π

+

K

+

K

−

K → B

LHCb

(after splitting by baryon number and triple-product variable
 => each plot represents about 1/4 of the signal in that mode) Run1

SLIDE 27

]

2

c [GeV/

−

pK

m

5.2 5.4 5.6 5.8

)

2

c Candidates / ( 10 MeV/

200 400 600 800 1000

LHCb

−

pK →

b

Λ

−

π p →

b

Λ

+

π

−

K → B

−

K

+

K →

s

B

• Comb. bkg.
• Part. reco. bkg.

]

2

c [GeV/

−

π p

m

5.2 5.4 5.6 5.8

)

2

c Candidates / ( 10 MeV/

100 200 300 400 500 600 700 800

LHCb

−

π p →

b

Λ

−

pK →

b

Λ

−

π

+

K → B

−

π

+

π → B

• Comb. bkg.
• Part. reco. bkg.

CPV in baryon decays?

27

JHEP 08 (2018) 039

Searches in other 4-body decays: no evidence. Searches in 2-body decays: no evidence.

arXiv:1807.06544

ApK−

CP

= −0.020 ± 0.013 ± 0.019, Apπ−

CP

= −0.035 ± 0.017 ± 0.020,

Example mass plots (simultaneous fit to 8 final states)

(after splitting by baryon number => each plot represents about 1/2 of the signal in that mode) Run1

SLIDE 28

CPV in baryon decays?

28

JHEP 08 (2018) 039

Searches in other 4-body decays: no evidence. Searches in 2-body decays: no evidence.

arXiv:1807.06544

Search in 𝛭b → p K− 𝜈+ 𝜈−: no evidence of CPV (but first observation of the decay mode!)

JHEP 06 (2017) 108

∆ACP = (3.5 ± 5.0 (stat) ± 0.2 (syst)) ⇥ 10−2, a

b T-odd CP

= ( 1.2 ± 5.0 (stat) ± 0.7 (syst)) ⇥ 10−2,

Example mass plot:

]

2

c ) [GeV/

−

µ

+

µ

−

K p ( m 5.4 5.5 5.6 5.7 5.8 )

2

c Candidates / (8 MeV/ 10 20 30 40 50 60

data

−

µ

+

µ

−

K p →

b

Λ Full fit Signal Background

>0

T

C

LHCb

)

(after splitting by baryon number and triple-product variable => plot represents about 1/4 of the signal) Run1

SLIDE 29

CPV in baryon decays?

• Strangely elusive!
• Awaiting update of 𝛭b → p π− π+ π− with more stats

29

JHEP 08 (2018) 039

Searches in other 4-body decays: no evidence. Searches in 2-body decays: no evidence.

arXiv:1807.06544

Search in 𝛭b → p K− 𝜈+ 𝜈−: no evidence of CPV

JHEP 06 (2017) 108

SLIDE 30

Other studies

30

ACP(B− → D−

s D0) = (−0.4 ± 0.5 ± 0.5)%,

ACP(B− → D−D0) = ( 2.3 ± 2.7 ± 0.4)%,

Search for CPV in B− → Ds− D0, B− → D− D0 (expected to be small, ~ 10−2, in SM)

JHEP 05 (2018) 160 PRL 120, 261801 (2018)

Amplitude analysis of B0 → Ks π+ π−,
 first observation of CPV in B0 → K*(892)+ π−

Run1 Run1

]

2

c ) [MeV/

−

π

+

π

S

K ( m

5200 5400 5600 5800

)

2

c Candidates / ( 16.25 MeV/

500 1000

LHCb

−

π

+

π

S

K → B

−

π

+

π

S

K →

s

B combinatorial

±

π

±

K

S

K → B

±

π

±

K

S

K →

s

B (X)

−

π

+

π

S

K →

(s)

B

ACP(K∗(892)−π+) = − 0.308 ± 0.060 ± 0.011 ± 0.012 ACP((Kπ)−

0 π+)

= − 0.032 ± 0.047 ± 0.016 ± 0.027 ACP(K∗

2(1430)−π+)

= − 0.29 ± 0.22 ± 0.09 ± 0.03 ACP(K∗(1680)−π+) = − 0.07 ± 0.13 ± 0.02 ± 0.03 ACP(f0(980)K0

S)

= 0.28 ± 0.27 ± 0.05 ± 0.14

Isobar formalism. Kπ S-wave modelled with EFKLLM parameterisation (factorisation)

El-Bennich et al, PRD 79:094005 (2009) 6𝜏

SLIDE 31

Leptons in B decays

• Very rare & forbidden decays often sensitive to NP

.

• Several well-known anomalies
• Apparent pattern of effects at 2, 3, even 4𝜏...
• ... but no 5𝜏 observation so far. At last CKM:

31

Angular analysis of B0àK*µ+µ

see e.g. JHEP 05 (2013) 137

• Well established “anomaly”

– Observables are q2 (dimuon mass squared) and 3 angles – Angular distribu*ons provide many observables sensi*ve to different sources of New Physics – Some global theore*cal fits require non-SM contribu*ons to accommodate the data – However, genuine QCD effects can also be an explana*on à more efforts needed to clarify the picture

JHEP 02 (2016) 104 arXiv:1604.04042

see e.g. JHEP 06 (2016) 092 see e.g. JHEP 06 (2016) 116

25 26

• Measurements of R(D) and R(D*) by BaBar, Belle and LHCb

– Overall average shows a 4σ discrepancy from the SM

• More analyses about " → #$% are ongoing at Belle and LHCb
• LHCb can also perform measurements with other b hadrons

– e.g. Bs, Bc and Λb decays will help to beOer understand the global picture à stay tuned!

LFU in BàD(*)τν τν

• Ra*o RD

() = !(B→D()τν) /

(B→D()τν) / !(B→D()μν) is sensi*ve e.g. (B→D()μν) is sensi*ve e.g. to charged Higgs scenarios

More LFU tests

• Ra*o (RK) of branching frac*ons of B+àK+μ+μ to

B+àK+e+e expected to be unity in the SM with excellent precision

– Observa*on of LFU viola*on would be a clear sign of New Physics – LHCb observed a 2.6σ devia*on from SM in the low q2 region – New measurements expected soon, e.g. RK*

• Phys. Rev. LeO. 113 (2014) 151601

27

Vincenzo Vagnoni, CKM 2016

P'5 in B0 → K*0 𝜈+ 𝜈− 3.4𝜏 global RK in B+ → K+ ℓ+ ℓ− 2.6𝜏 at low q2 HFLAV: 4𝜏 overall

R(D), R(D*) in B → D(*)l+νl

• What's new since CKM 2016?

SLIDE 32

Decay time [ps] 5 10

candidates / (1 ps)

−

µ

+

µ →

s

Weighted B

2 4 6 8

Effective lifetime fit

LHCb

4.4 fb−1

• Bs → 𝜈+ 𝜈− first observed by CMS & LHCb jointly
• See also ATLAS measurement EPJC 76 (2016) 513
• Update from LHCb with 4.4/fb (Run1+partial Run2)
• Significance 7.8𝜏
• BR measured:


assuming that only heavy mass eigenstate decays to 𝜈+ 𝜈− (per SM)

• Effective lifetime measured: 2.04 ± 0.44 ± 0.05 ps


consistent with SM: 𝜐(Bs → 𝜈+ 𝜈−) = 𝜐Bs / (1 − ys)

• Upper limit: B(B0 → 𝜈+ 𝜈−) < 3.4 x 10−10 @ 95% CL

Very rare & forbidden decays

32

]

2

c [MeV/

−

µ

+

µ

m 5000 5200 5400 5600 5800 6000 )

2

Candidates / ( 50 MeV/c 5 10 15 20 25 30 35

Total

−

µ

+

µ →

s

B

−

µ

+

µ → B Combinatorial

−

h'

+

h →

(s)

B

µ

ν

+

µ )

−

(K

−

π →

(s)

B

−

µ

+

µ

0(+)

π →

0(+)

B

µ

ν

−

µ p →

b

Λ

µ

ν

+

µ ψ J/ →

+ c

B

LHCb BDT > 0.5

ℬ(B0

s → μ+μ−) = (3.0 ± 0.6+0.3 −0.2) × 10−9

Nature 522 (2015) 68 PRL 118, 191801 (2017)

SLIDE 33

ATLAS estimated sensitivities

• At HL-LHC (3000 fb−1),

can measure B(B0 → 𝜈+ 𝜈−) precisely.

33

2 3 4 5 6 ]

• 9

) [10

• µ

+

µ →

s

B( B 0.1 − 0.1 0.2 0.3 0.4 0.5 0.6 ]

• 9

) [10

• µ

+

µ → B( B

ATLAS Simulation Preliminary

• µ

+

µ →

(s)

B working point x15 Run1 statistics stat + syst stat only SM prediction

Run2 "Conservative" HL-LHC (15xRun1)

2 3 4 5 6 ]

• 9

) [10

• µ

+

µ →

s

B( B 0.1 − 0.1 0.2 0.3 0.4 0.5 0.6 ]

• 9

) [10

• µ

+

µ → B( B

ATLAS Simulation Preliminary

• µ

+

µ →

(s)

B working point x75 Run1 statistics stat + syst stat only SM prediction

"High-yield" HL-LHC (75xRun1)

2 3 4 5 6 ]

• 9

) [10

• µ

+

µ →

s

B( B 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 ]

• 9

) [10

• µ

+

µ → B( B SM

ATLAS Simulation Preliminary

• µ

+

µ →

(s)

B Neyman contours Run-2 statistics likelihood contours Run-2 statistics

• Approx. precision of LHCb

measurement on prev. slide ATL-PHYS-PUB-2018-005

SLIDE 34

Candidates

1 10

2

10

3

10

4

10

LHCb

Data Total Signal × 1 − Background

Neural network output

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Pull

5 − 5

Very rare & forbidden decays

• Bs → 𝜐+ 𝜐− expected to have larger BR...
• ... but experimentally tougher


=> never observed

• Search: (B0, Bs) → 𝜐+ 𝜐− with 𝜐 → π− π+ π− 𝜉𝜐
• Mass resolution too poor to disentangle the two
• Use pion kinematics to identify signal


(good-𝜐) and control regions: 


• Fit output of a NN selector with signal & control regions:

34

τ− → aa(1260)−ντ, a1(1260)− → ρ(770)0π−

Assuming negligible B0 → 𝜐+ 𝜐−, B(Bs → 𝜐+ 𝜐−) < 6.8 x 10−3 @ 95% CL ... first limit on this process Assuming negligible Bs → 𝜐+ 𝜐−, B(B0 → 𝜐+ 𝜐−) < 2.1 x 10−3 @ 95% CL
 ... improves on previous BaBar limit by factor 2.6

PRL 118, 251802 (2017) Run1 BaBar, PRL 96 (2006) 241802

SLIDE 35

Very rare & forbidden decays

• B(s) → 𝜈± e∓ forbidden in SM; sensitive

to BSM CLFV

• Search with LHCb Run1 data.
• Fit in bins of BDT output, presence/

absence of brem photon for e±

• No signal; set limits at 95% CL:
• B(B0 → 𝜈± e∓) < 1.3 x 10−9
• B(Bs → 𝜈± e∓) < 6.3 x 10−9 


[or 7.2 x 10−9 if dominated by light mass eigenstate instead]

• Normalisation: B0 → K+ π− 


and B+ → J/𝜔 K+

35

5 10 15

[0.25, 0.4]

5 10 15

[0.25, 0.4]

5 10 15

[0.4, 0.5]

5 10 15

[0.4, 0.5]

5 10 15

[0.5, 0.6]

5 10 15

[0.5, 0.6]

)

2

c Candidates / ( 50 MeV/

2 4 6 8 10

[0.6, 0.7]

2 4 6 8 10

[0.6, 0.7]

2 4 6 8 10

[0.7, 0.8]

2 4 6 8 10

[0.7, 0.8]

2 4 6 8 10

[0.8, 0.9]

2 4 6 8 10

[0.8, 0.9]

]

2

c [MeV/

±

µ

±

e

m

5000 5200 5400 5600 5800 2 4 6 8 10

[0.9, 1.0]

]

2

c [MeV/

±

µ

±

e

m

5000 5200 5400 5600 5800 2 4 6 8 10

[0.9, 1.0]

Data Total Combinatorial ν

−

µ p →

b

Λ ν

+

µ

−

π → B

±

µ

±

e

→

s

B

±

µ

±

e

→ B

LHCb

JHEP 1803 (2018) 078 Run1

SLIDE 36

• ... i.e. ratio of BFs to H𝜈𝜈, Hee.
• Theoretically very clean: hadronic uncertainties cancel in ratio.
• In SM, close to 1 (small differences due to phase space):

Lepton flavour universality

36

RH =

R dΓ(B→Hµ+µ−)

dq2

dq2

R dΓ(B→He+e−)

dq2

dq2

Notation:

Table 1: Recent SM predictions for RK∗0.

q2 range [ GeV2/c4 ] RSM

K∗0

References [0.045, 1.1] 0.906 ± 0.028 BIP [26] 0.922 ± 0.022 CDHMV [27–29] 0.919

+ − 0.004 0.003

EOS [30,31] 0.925 ± 0.004 flav.io [32–34] 0.920

+ − 0.007 0.006

JC [35] [1.1, 6.0] 1.000 ± 0.010 BIP [26] 1.000 ± 0.006 CDHMV [27–29] 0.9968

+ − 0.0005 0.0004

EOS [30,31] 0.9964 ± 0.005 flav.io [32–34] 0.996 ± 0.002 JC [35]

Example: predictions for RK* in two q2 ranges. Refs defined in arXiv:1705.05802

SLIDE 37

5 10 15 20

q2 [GeV2/c4]

0.0 0.5 1.0 1.5 2.0

RK∗0

LHCb

LHCb BaBar Belle

RK*

• Use double ratio to cancel systematics:

37

→ → RK∗0 = B(B0 → K⇤0µ+µ) B(B0 → K⇤0J/ ( → µ+µ))

• B(B0 → K⇤0e+e)

B(B0 → K⇤0J/ (→ e+e))

]

2

c ) [MeV/

−

e

+

e

−

π

+

K ( m

4500 5000 5500 6000 2

c Candidates per 34 MeV/

2 −

10

1 −

10 1 10

LHCb Signal Combinatorial

−

e

+

Xe → B

4500 5000 5500 6000 2

c Candidates per 34 MeV/

5 10 15 20 25

LHCb

−

e

+

e

*

K → B Combinatorial

−

e

+

Xe → B

]

4

c /

2

<1.1 [GeV

2

q 0.045<

]

2

c ) [MeV/

−

e

+

e

−

π

+

K ( m

4500 5000 5500 6000

Pulls

5 − 5 5

]

2

c ) [MeV/

−

e

+

e

−

π

+

K ( m

4500 5000 5500 6000 2

c Candidates per 34 MeV/

2 −

10

1 −

10 1 10

LHCb Signal Combinatorial ee )

*

YK → ( X → B ee) → ( ψ / J

*

K → B

4500 5000 5500 6000 2

c Candidates per 34 MeV/

5 10 15 20 25 30 35

LHCb

−

e

+

e

*

K → B Combinatorial

−

e

+

Xe → B ψ / J

*

K → B

]

4

c /

2

<6.0 [GeV

2

q 1.1<

]

2

c ) [MeV/

−

e

+

e

−

π

+

K ( m

4500 5000 5500 6000

Pulls

5 − 5 5 2

c Candidates per 34 MeV/

5200 5400 5600 5800 2

c Candidates per 10 MeV/

10 20 30 40 50 60 70 80 90

LHCb

−

µ

+

µ

*

K → B Combinatorial

]

4

c /

2

<1.1 [GeV

2

q 0.045<

]

2

c ) [MeV/

−

µ

+

µ

−

π

+

K ( m

5200 5400 5600 5800

Pulls

5 − 5 5

5200 5400 5600 5800 2

c Candidates per 10 MeV/

10 20 30 40 50 60 70 80

LHCb

−

µ

+

µ

*

K → B Combinatorial

]

4

c /

2

<6.0 [GeV

2

q 1.1<

]

2

c ) [MeV/

−

µ

+

µ

−

π

+

K ( m

5200 5400 5600 5800

Pulls

5 − 5 5

3

10

0.045 < q2 < 1.1 GeV2 1.1 < q2 < 6.0 GeV2

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

RK result, comparison

JHEP 08 (2017) 055 Run1

SLIDE 38

5 10 15 20

q2 [GeV2/c4]

0.0 0.5 1.0 1.5 2.0

RK∗0

LHCb

LHCb BaBar Belle

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

RK*

• Compatibility with / deviation from SM depends on what model

you choose, but roughly:
 2.1 - 2.3𝜏 in low-q2 region
 2.4 - 2.5𝜏 in central-q2 region

• Compatible with, but more precise than, BABAR & Belle.

38

RK∗0 = ( 0.66 + 0.11

− 0.07 (stat) ± 0.03 (syst)

for 0.045 < q2 < 1.1 GeV2/c4 0.69 + 0.11

− 0.07 (stat) ± 0.05 (syst)

for 1.1 < q2 < 6.0 GeV2/c4

JHEP 08 (2017) 055

SLIDE 39

Lepton flavour universality II

39

R(D*) ≡ B0 → D*+τ−¯ ντ B0 → D*+μ−¯ νμ R(J/ψ) ≡ B+

c → J/ψ τ+ντ

B+

c → J/ψ μ+νμ

R(D)

0.2 0.3 0.4 0.5 0.6

R(D*)

0.2 0.25 0.3 0.35 0.4 0.45 0.5

BaBar, PRL109,101802(2012) Belle, PRD92,072014(2015) LHCb, PRL115,111803(2015) Belle, PRD94,072007(2016) Belle, arXiv:1608.06391 Average

SM Predictions

= 1.0 contours

2

χ Δ

R(D)=0.300(8) HPQCD (2015) R(D)=0.299(11) FNAL/MILC (2015) R(D*)=0.252(3) S. Fajfer et al. (2012)

) = 70%

2

χ P(

HFAG

Summer 2016

At last CKM, 3.9𝜏 tension
 (HFLAV)

SLIDE 40

R(D*)

• Reconstruct 𝜐 → π− π+ π− (π0) 𝜉𝜐, complementary to previous

measurement of R(D*)

• Normalise in steps. First measure B0 → D*0 𝜐+ 𝜉𝜐 relative to

topologically similar B0 → D*− π+ π− π+:
 
 
 
 ... with Nsig from fit to (q2, decay time of tau, BDT output
 ... and Nnorm from fit to m(D*− π+ π− π+)

• Then, use known BFs of [B0 → D*0 𝜐+ 𝜉𝜐] and [B0 → D*− 𝜈+ 𝜉𝜈]:

40

PRL 120, 171802 (2018)
 PRD 97, 072013 (2018)

R(D*) ≡ B0 → D*+τ−¯ ντ B0 → D*+μ−¯ νμ

K(D∗−) ≡ B(B0 → D∗−τ +ντ) B(B0 → D∗−3π) = Nsig Nnorm εnorm εsig 1 B(τ + → 3πντ) + B(τ + → 3ππ0ντ),

R(D∗−) = K(D∗−) × B(B0 → D∗−3π)/B(B0 → D∗−µ+νµ),

Input: avg of
 BABAR, Belle, LHCb Input: HFLAV

SLIDE 41

0.5 1.0 1.5 2.0

[ps]

τ

t

10 20 30 40 500

0.0005 0.001 0.0015 0.002 100 200 300 400 5000 0.0005 0.001 0.0015 0.002 200 400 600 800 1000 1200 14000 0.0005 0.001 0.0015 0.002 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

Candidates / (0.25ps)

2 4 6 8 10

]

4

c /

2

[GeV

2

q

10 20 30 40 50 60 Data Total model

τ

ν

+

τ −

*

D → B

τ

ν

+

τ

**

D → B (X)

+ s

D −

*

D → B (X)

+

D −

*

D → B X π 3 −

*

D → B (X) D −

*

D → B

• Comb. bkg

5 10 100 200 300 400 5000 5 10 200 400 600 800 10000 5 10 200 400 600 800 1000 1200 1400 1600 1800

)

4

c /

2

Candidates / (1.375GeV

LHCb

R(D*)

• Nsig = 1296 ± 86

41

Two projections of fits for Nsig in bins of BDT

K(D∗−) = 1.97 ± 0.13 (stat) ± 0.18 (syst)

R(D∗−) = 0.291 ± 0.019 (stat) ± 0.026 (syst) ± 0.013 (ext)

0.2 0.3 0.4 0.5 0.6

R(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 contours

2

χ Δ

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

) = 74%

2

χ P( σ 4 σ 2

HFLAV

Summer 2018

• Putting it all together:

Updated HFLAV -- 3.6-3.8𝜏 tension

PRL 120, 171802 (2018)
 PRD 97, 072013 (2018)

• Systematics dominated.
• Several all of similar size; not going

to be easy to reduce them all.

Run1

R(D*) ≡ B0 → D*+τ−¯ ντ B0 → D*+μ−¯ νμ

SLIDE 42

5 5 10

)

4

/c

2

Candidates / ( 0.6 GeV

1000 2000 3000 4000 5000

]

4

/c

2

[GeV

miss 2

m

5 − 5 10

Pulls

5 − 5 LHCb 0.5 1 1.5 2

Candidates / ( 0.376 ps )

2000 4000 6000 8000 10000 12000 14000 16000

decay time [ps]

0.5 1 1.5 2

Pulls

5 − 5 LHCb

Data µ ν + µ ψ J/ → + c B Mis-ID bkg.

• comb. bkg.

µ + ψ J/

• comb. bkg.

ψ J/ + c H ψ J/ → + c B l ν + l (1P) c χ → + c B l ν + l (2S) ψ → + c B τ ν + τ ψ J/ → + c B

R(J/𝜔)

• SM predictions: R(J/𝜔) ~ 0.25-0.28
• Uses


=> final state for both numerator & denominator is 𝜈𝜈𝜈

• Templated fit to (m2miss, Bc decay time) in eight kinematic bins
• 1400 ± 300 signal, 19140 ± 340 normalisation

42

PRL 120, 121801 (2018)

R(J/ψ) ≡ B+

c → J/ψ τ+ντ

B+

c → J/ψ μ+νμ

Run1

Anisimov et al, PLB 452:129 (1999) Kiselev, hep-ph/0211021 Ivanov et al, PRD 73:054024 (2006) Hernandez et al, PRD 74:074008 (2006)

τ− → μ−ντ¯ ντ

Fit projections

R(J/ψ) = B(B+

c → J/ψτ +ντ)

B(B+

c → J/ψµ+νµ) = 0.71 ± 0.17 (stat) ± 0.18 (syst).

... within 2𝜏 of the SM prediction.

Dominant sys err:
 Bc → J/𝜔 form factors

SLIDE 43

b→s and b→d transitions

43

b s µ− µ+ t W γ, Z0

SM contributions... ... and maybe BSM too?

Leptoquarks

b µ− µ+ s LQ

New heavy gauge bosons

b s µ+ µ Z0

... or your favourite model...

Thanks to C. Langenbruch

Supersymmetry

b s µ− µ+ ˜ t ˜ W

SLIDE 44

Observables

• We can look at distributions of decay rate vs q2
• ... or do a full angular analysis and look at


angular observables vs q2

• Use "optimised" variables to help cancel hadronic effects, e.g. P'5
• To pull the information together, use Wilson coefficients:
• Main interest in EW penguin operators: C9, C'9, C10, C'10
• So, what's new since last CKM?

44

Thanks to C. Langenbruch

Heff = −4GF √ 2 VtbV ∗

ts

e2 16⇡2 X

i

Ci Oi

Wilson coefficient (“effective coupling”) Local operator

∆HNP =  Λ2

NP

Oi

Flavour-violating coupling NP scale

Optimised variables: Descotes-Genon et al, JHEP , 1301:048, 2013, JHEP , 1305:137, 2013

SLIDE 45

Angular analysis of B+ → K+ 𝜈− 𝜈+

• 2D fit of AFB and FH (scalar/pseudoscalar/tensor contribution)

in bins of q2. SM predictions close to zero.

• Control regions: B+ → K+ J/𝜔, B+ → K+ 𝜔(2S)
• Total yield outside control regions in 1<q2<22 GeV: 2286 ± 73

45

arXiv:1806.00636 √s=8 TeV, 20.5 fb−1

)

2

(GeV

2

q

5 10 15 20

FB

A

0.4 − 0.2 − 0.2 0.4

Data (8 TeV)

• 1

20.5 fb CMS

)

2

(GeV

2

q

5 10 15 20

H

F

0.5 1 1.5

Data DHMV (8 TeV)

• 1

20.5 fb CMS

Consistent with SM.

DHMV: JHEP12(2014)125, JHEP 06 (2016) 092

SLIDE 46

Angular analysis of B0 → K*0 𝜈− 𝜈+

• More complex final state => need more angular
• bservables! Here, focus on P1, P'5.
• Same dataset previously used to measure AFB of muons, K*0

longitudinal polarisation FL, and dB/dq2. [PLB 753 (2016) 424]

• 4D fits in q2 bins, as fn of mass and three angles 𝜄l, 𝜄K, 𝜒.
• Parameters AFB, FL, FS fixed to values from previous

analysis; this drives the largest systematic uncertainty.

46

PLB 781 (2018) 517 √s=8 TeV, 20.5 fb−1

) (GeV)

−

μ

+

μ

−

π

+

Κ ( m 5 5.1 5.2 5.3 5.4 5.5 Events / ( 0.028 GeV ) 10 20 30 40 50 60

CMS

(8 TeV)

1 −

20.5 fb

2

< 4.3 GeV

2

q 2 < Data Total fit Correctly tagged signal Mistagged signal Background

θℓ

−

θ

−

φ

−

−

μ

+

μ

−

π

+

Κ

−

θ

−

θ

−

φ

−

Example fit projection from one q2 bin

K+ π− θK PB0 K*0 rest frame μ− μ+ θℓ PB0 μ+μ− rest frame μ− μ+ K+ π− φ B0 rest frame Figure 1: Illustration of the angular variables θ` (left), θK (middle), and ϕ (right) for the decay B0 ! K⇤0(K+π)µ+µ.

SLIDE 47

Angular analysis of B0 → K*0 𝜈− 𝜈+

• 1397 signal events
• Results in agreement with SM, qualitatively compatible

with LHCb.

47

PLB 781 (2018) 517 √s=8 TeV, 20.5 fb−1 SM-DHMV: JHEP , 1301:048, 2013, JHEP , 1305:137, 2013

)

2

(GeV

2

q

2 4 6 8 10 12 14 16 18 20

1

P

1.5 − 1 − 0.5 − 0.5 1 1.5 2 2.5 3 CMS LHCb SM-DHMV

)

2

(GeV

2

q

2 4 6 8 10 12 14 16 18 20

5

P'

1.5 − 1 − 0.5 − 0.5 1 1.5 CMS LHCb Belle SM-DHMV

SLIDE 48

Angular analysis of B0 → K*0 𝜈− 𝜈+

• Same final state, general approach (angular analysis in bins of q2)
• but focus on low-q2 region, 0.04 to 6.0 GeV2
• Overall signal yield: 342 ± 39
• Compatible with predictions and with LHCb, CMS, Belle.

48

arXiv:1805.04000 √s=8 TeV, 20.3 fb−1

q2 [GeV2] nsignal nbackground [0.04, 2.0] 128 ± 22 122 ± 22 [2.0, 4.0] 106 ± 23 113 ± 23 [4.0, 6.0] 114 ± 24 204 ± 26 [0.04, 4.0] 236 ± 31 233 ± 32 [1.1, 6.0] 275 ± 35 363 ± 36 [0.04, 6.0] 342 ± 39 445 ± 40

[MeV]

µ µ π K

m 5200 5400 5600 Events / 25 MeV 50 100

• 1

= 8 TeV, 20.3 fb s ATLAS

2

[0.04, 6.0] GeV ∈

2

S5 fold, q

Data Total Fit Model Signal Background

Example fit projection from q2 range used

2 4 6 8 10

]

2

[GeV

2

q

1 − 0.5 − 0.5 1 1.5 2

5

P'

Data CFFMPSV fit theory DHMV theory JC

ATLAS

• 1

= 8 TeV, 20.3 fb s

CFFMPSV: JHEP 1606 (2016) 116 DHMV: JHEP 1412 (2014) 125 JC: JHEP 1305 (2013) 043 , PRD 93, 014028 (2016)

SLIDE 49

i

K

5 10

Value

0.4 − 0.2 − 0.2 0.4

LHCb

SM prediction

• Run1+2015+2016. Updates & expands on PAPER-2015-009
• Study angular moments at high-q2 (low hadronic recoil):


15 < q2 < 20 GeV2/c4

• System has 5 d.o.f. due to spins


in final state, 𝛭b0 polarisation

• Full angular distribution can be


written as sum of 34 terms:
 
 
 ... though most (i>10) vanish in
 limit of small 𝛭b0 polarisation

• Consistent with SM (EOS)

49

arXiv:1808.00264

]

2

c ) [MeV/

−

µ

+

µ

−

π p ( m

5400 5500 5600 5700 5800

)

2

c Candidates / (20 MeV/

20 40 60

LHCb

−

π p long 2011 + 2012

]

2

c ) [MeV/

−

µ

+

µ

−

π p ( m

5400 5500 5600 5700 5800

)

2

c Candidates / (20 MeV/

20 40 60 80 100

LHCb

−

π p downstream 2011 + 2012

]

2

c ) [MeV/

−

µ

+

µ

−

π p ( m

5400 5500 5600 5700 5800

)

2

c Candidates / (20 MeV/

20 40 60

LHCb

−

π p long 2015 + 2016

]

2

c ) [MeV/

−

µ

+

µ

−

π p ( m

5400 5500 5600 5700 5800

)

2

c Candidates / (20 MeV/

20 40 60 80 100

LHCb

−

π p downstream 2015 + 2016

d5Γ d~ Ω = 3 32⇡2

34

X

i

Kifi(~ Ω)

A`

FB = 3 2K3 = −0.39 ± 0.04 ± 0.01

Ah

FB = K4 + 1 2K5 = −0.30 ± 0.05 ± 0.02

A`h

FB = 3 4K6 = +0.25 ± 0.04 ± 0.01

5 fb−1

Angular analysis of 𝛭b → 𝛭 𝜈− 𝜈+

Mass fits by event category First 10 observables

SLIDE 50

Polarisation, helicity in 𝛭b → 𝛭 J/𝜔

• ... but we can also measure the polarisation!
• Done by CMS (in different kinematic region)
• Also determine angular parameters describing decay.

50

PRD 97, 072010 (2018)

) [GeV] Λ ψ m (J/

5.58 5.6 5.62 5.64 5.66

Events / 3 MeV

100 200 300 400 Data Fit Signal Background (7 TeV)

• 1

(8 TeV) + 5.2 fb

• 1

19.8 fb

CMS

(a)

√s=7 TeV, 5.2 fb−1 √s=8 TeV, 20.3 fb−1

P = 0.00 ± 0.06, α1 = 0.14 ± 0.14, α2 = −1.11 ± 0.04, γ0 = −0.27 ± 0.08,

|T++|2 =

0.05 ± 0.04,

|T+0|2 = −0.10 ± 0.04, |T−0|2 =

0.51 ± 0.03,

|T−−|2 =

0.52 ± 0.04,

Example mass projection from 4D fit

SLIDE 51

Rare Decays Round-up

• If interpreted as NP

, simplest explanation: shift in C9

• leptoquarks? Z'?
• ... or is it just hadronic SM gunge (charm loops)?
• For more, see plenary talks on Friday.

51

−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0 1.5

Re CNP

9 −1.5 −1.0 −0.5 0.0 0.5 1.0 1.5 2.0

Re CNP

10

flavio v0.21.2

ATLAS CMS LHCb BR only all

[EPJC 77 (2017) 377]

Coeff. best fit 1σ pull CNP

9

−1.21 [−1.41, −1.00] 5.2σ C0

9

+0.19 [−0.01, +0.40] 0.9σ CNP

10

+0.79 [+0.55, +1.05] 3.4σ C0

10

−0.10 [−0.26, +0.07] 0.6σ CNP

9

= CNP

10

−0.30 [−0.50, −0.08] 1.3σ CNP

9

= −CNP

10

−0.67 [−0.83, −0.52] 4.8σ C0

9 = C0 10

+0.06 [−0.18, +0.30] 0.3σ C0

9 = −C0 10

+0.08 [−0.02, +0.18] 0.8σ CNP

9 , CNP 10

(−1.15, +0.26) — 5.0σ CNP

9 , C0 9

(−1.25, +0.59) — 5.3σ CNP

9 , C0 10

(−1.34, −0.39) — 5.4σ C0

9, CNP 10

(+0.25, +0.83) — 3.2σ C0

9, C0 10

(+0.23, +0.04) — 0.5σ CNP

10 , C0 10

(+0.79, −0.05) — 3.0σ

Example global fit Altmannshofer et al, EPJC 77 (2017) 377

SLIDE 52

Spectroscopy

52

Recreation from memory of slide by M. Pennington, Hirschegg 2007, using diagram from CMS: JHEP 03 (2018) 167 Physics at the LHC will be all about SUSY*! Why do you bother studying hadrons? They're dinosaurs!

* Substitute "lepton flavour anomalies" if you prefer...

SLIDE 53

Spectroscopy

53

Recreation from memory of slide by M. Pennington, Hirschegg 2007 using diagram from CMS: JHEP 03 (2018) 167

SLIDE 54

𝜓b1(3P) and 𝜓b2(3P)

• Individual states 𝜓b1(3P) and

𝜓b2(3P) resolved & observed for the first time.

• 𝜓b0(3P) → 𝛷𝛿 BF negligible.
• Consistent with conventional

states.

54

PRL 121, 092002 (2018) √s=13 TeV, 80 fb−1

9 9.5 10 10.5 11 Dimuon mass (GeV) 20 40 60 80

3

10 ×

Events / 2.5 MeV Y(2S) Y(3S) Y(1S)

CMS

= 13 TeV s = 13 TeV

• 1

L = 80.0 fb y < 0.6 0.6 < y < 1.2

𝛷(nS) → 𝜈+ 𝜈−

+ converted photon

9.8 10.2 10.6 Y(nS) γ invariant mass (GeV) 200 400 600 800 1000 1200 Events / 3.5 MeV

= 13 TeV s = 13 TeV

• 1

L = 80.0 fb

CMS

(2P)

b

χ

(3P)

b

χ

(1P)

b

χ

Y(1S) + γ Y(2S) + γ Y(3S) + γ 9890 9895 10250 10255

→ 1P 1S → 2P 1S → 2P 2S

χ (nP) mass (MeV)

b1

10.4 10.45 10.5 10.55 10.6 invariant mass (GeV)

γ

Y(3S) 20 40 60 80 100 Events / 3 MeV

Total fit (3P)

b1,2

χ Signal Background

= 13 TeV s

• 1

L = 80.0 fb

CMS

zoom in

Unbinned fit Merged 𝜓b(3P) structure observed by ATLAS: PRL 108 (2012) 152001

SLIDE 55

55

The ongoing X(5568) mystery

SLIDE 56

X(5568) : The D0 observation

56

Feb 2016: D0 reported a narrow structure in the Bs0 π± spectrum (with Bs0 → J/𝜔 𝜚).
 Manifestly exotic bsqq resonance.

D0, PRL 117, 022003 (2016)

m = 5567.8 ± 2.9 (stat)+0.9

−1.9 (syst) MeV/c2

Γ = 21.9 ± 6.4 (stat)+5.0

−2.5 (syst) MeV

Yield: 133±31 events
 Significance: 6.1σ stat, or 5.1σ stat+sys (inc LEE) Eff-cor yield ratio 𝜍(X/Bs0):

10 < pT (B0

s) < 15 GeV/c : (9.1 ± 2.6 ± 1.6)%

15 < pT (B0

s) < 30 GeV/c : (8.2 ± 1.9 ± 1.4)%

average : (8.6 ± 1.9 ± 1.4)%

But then...

4.8 5 5.2 5.4 5.6 5.8 6 500 1000 1500 2000

]

2

) [GeV/c φ ψ /

J

(

m

2

N events / 20 MeV/c

• 1

D0 Run II, 10.4 fb

Inclusive Bs0 sample (5.6k sig)

10 20 30 40 50 60 70 80 90

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

DATA Fit with background shape fixed Background Signal

(a)

15

π

5.5 5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9

]

2

) [GeV/c

±

π

S

(B

m

Bs0 π±

X(5568)

Add π± Mass and width:

This is a lot!

SLIDE 57

X(5568) : Not seen at LHCb

57 LHCb:, PRL 117, 152003 (2016)

Candidates / (5 MeV)

100 200 300 400 500 600 700 800 900 Claimed X(5568) state Combinatorial

) > 5 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

Candidates / (5 MeV)

50 100 150 200 250 Claimed X(5568) state Combinatorial

) > 10 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

Candidates / (5 MeV)

10 20 30 40 50 60 70 80 90 Claimed X(5568) state Combinatorial

) > 15 GeV

s

B (

T

p LHCb

Pull

4 − 2 − 2 4

(MeV) )

±

π

s

m(B

5550 5600 5650 5700 5750 5800 5850 5900 5950 6000

(MeV) )

+

π

s

• m(D

5300 5350 5400 5450 5500 5550 5600

Candidates / (3 MeV)

1000 2000 3000 4000 5000 6000

LHCb (MeV) ) φ ψ m(J/

5200 5250 5300 5350 5400 5450 5500

Candidates / (3 MeV)

2000 4000 6000 8000 10000 12000

LHCb }

106k Bs0 Add π±, try various pT cuts... Upper limits set on (X/Bs) cor. yield ratio:

⇢LHCb

X

(pT(B0

s) > 5 GeV)

< 0.011 (0.012) , ⇢LHCb

X

(pT(B0

s) > 10 GeV)

< 0.021 (0.024) , ⇢LHCb

X

(pT(B0

s) > 15 GeV)

< 0.018 (0.020) .

... vs (8.6 ± 1.9 ± 1.4)% at D0 (but different environment) And then...

at 90% (95%) CL

Bs0 → J/𝜔 𝜚

Bs0 → Ds− π+

Aug 2016: LHCb tries to confirm peak, finds nothing despite larger Bs0 sample, extra mode.

SLIDE 58

X(5568) : Nor at CMS

58 CMS: PRL 120, 202005 (2018)

) [GeV]

−

K

+

K ψ M(J/

5.2 5.3 5.4 5.5

Candidates / 5 MeV

2000 4000 6000 8000 10000

278 ± 277 = 49

s B

N MeV 0.06 ± = 5366.54

s B

µ MeV 0.18 ± = 8.03

1

σ MeV 0.5 ± = 18.6

2

σ 0.02 ± = 0.47 f

Data Fit Signal Background (8 TeV)

• 1

19.7 fb

CMS

5.5 5.6 5.7 5.8 5.9

Candidates / 5 MeV

200 400 600 800

(a)

) > 10 GeV

s

(B

T

p Data Fit

(8 TeV)

• 1

19.7 fb

CMS ) [GeV]

±

π

s

(B

Δ

M

5.5 5.6 5.7 5.8 5.9

Pull

2 − 2

5.5 5.6 5.7 5.8 5.9

Candidates / 5 MeV

200 400 600

(b)

) > 15 GeV

s

(B

T

p Data Fit

(8 TeV)

• 1

19.7 fb

CMS ) [GeV]

±

π

s

(B

Δ

M

5.5 5.6 5.7 5.8 5.9

Pull

2 − 2

17 Dec 2017: CMS tries to confirm peak, also finds nothing.

49k Bs0 Add π±, try various pT cuts...

→

rX < 1.1% at 95% CL for pT(B0

s) > 10 GeV and

rX < 1.0% at 95% CL for pT(B0

s) > 15 GeV.

... vs (8.6 ± 1.9 ± 1.4)% at D0, but again different production environment. And just 10 days later...

Bs0 → J/𝜔 K+K−

SLIDE 59

2

c Candidates per 5 MeV/

2

c GeV/

)

±

π

s

M(B

5.5 5.6 5.7 5.8 5.9 20 40 60 80 100 120

signal region

s

B sideband regions

s

B

X(5568) : Nor at CDF

59

27 Dec 2017: CDF searches, finds nothing, sets UL.

2

c Candidates per 5 MeV/

2

c GeV/

) φ ψ M(J/

5.2 5.275 5.35 5.425 5.5 200 400 600 800

2

c Candidates per 5 MeV/

2

c GeV/

)

±

π

s

M(B

5.5 5.6 5.7 5.8 5.9 20 40 60 80 100 120

CDF, PRL 120, 202006 (2018)

3.6k Bs0 Add π±... Limit on corrected yield ratio: 𝜍(X/Bs) < 6.7% at 95% CL ... vs (8.6 ± 1.9 ± 1.4)% at D0.
 NB same environment And then just two days later...

Scaling D0 results to CDF...

Bs0 → J/𝜔 𝜚

SLIDE 60

X(5568) : D0 still sees it!

60

29 Dec 2017: D0 publishes second analysis with different decay mode: semileptonic
 Bs0 → Ds− μ+ X... 3.2σ signal!

D0, PRD 97, 092004 (2018

5.55 5.6 5.65 5.7 5.75 5.8 5.85 5.9 50 100 150 200 (a)

]

2

) [GeV/c

±

π

S

(B m

2

N events / 8 MeV/c

• 1

D0 Run II, 10.4 fb

Semileptonic Data Fit Background Signal Effect. Semileptonic Hadronic (from Ref. [15]) Cone cut No cone cut Cone cut No cone cut Fitted mass, MeV/c2 5566.4+3.4

−2.8 +1.5 −0.6

5566.7+3.6

−3.4 +1.0 −1.0

5567.8 ± 2.9+0.9

−1.9

5567.8 Fitted width, MeV/c2 2.0+9.5

−2.0 +2.8 −2.0

6.0+9.5

−6.0 +1.9 −4.6

21.9 ± 6.4+5.0

−2.5

21.9 Fitted number of signal events 121+51

−34 +9 −28

139+51

−63 +11 −32

133 ± 31 ± 15 106 ± 23 (stat) Local significance 4.3 σ 4.5 σ 6.6 σ 4.8 σ Significance with systematics 3.2 σ 3.4 σ 5.6 σ

• Significance with LEE+systematics
• 5.1 σ

3.9 σ

e obtain a production ratio f

• f

h 7.3+2.8

2.4 (stat)+0.6 1.7 (syst)

i %,

𝜍(X/Bs) = But a few weeks afterwards...

X(5568)

SLIDE 61

Events / 2 MeV 50 100 150 200 250 300 350

Data Signal (S) Background (B) Fit(S+B) D0 mass peak

) [MeV]

±

π

s

B ( m 5600 5700 5800

σ (data-fit)/

2 − 2

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s )> 15 GeV

s

(B

T

p

X(5568) : But ATLAS does not

61 ATLAS, PRL 120 (2018) 202007

) [MeV]

• K

+

K ψ J/ ( m 5200 5300 5400 5500 5600 Events / 5 MeV 1000 2000 3000 4000 5000 6000 7000 8000 9000

Data Signal (S) Background (B) Fit(S+B)

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s

6 Feb 2018: ATLAS joins the fray!

53k Bs0 Add π±, try various pT cuts...

Events / 2 MeV 100 200 300 400 500

Data Signal (S) Background (B) Fit(S+B) D0 mass peak

) [MeV]

±

π

s

B ( m 5600 5700 5800

σ (data-fit)/

2 − 2

ATLAS

• 1

=7 TeV, 4.9 fb s

• 1

=8 TeV, 19.5 fb s )> 10 GeV

s

(B

T

p

ρ(X/B0

s) < 1.5% at 95% CL for pT (B0 s) > 10 GeV/c

ρ(X/B0

s) < 1.6% at 95% CL for pT (B0 s) > 15 GeV/c

Limit on corrected yield ratio: Wow.

Bs0 → J/𝜔 K+K−

SLIDE 62

The ongoing X(5568) mystery

• This remains a mystery.
• LHC samples have much larger Bs0 stats and disfavour D0

result assuming conventional heavy quark production.

• ... but cannot rule it out absolutely due to different

production environments.

• CDF has the same environment as D0 and does not confirm

it... but lower stats => the UL does not fully rule it out.

• But perhaps by adding more decay modes, this might be resolved.
• LHCb was quicker off the mark (data model is better
• ptimised for B physics) but ATLAS and CMS Run1 data

samples had comparable statistics in the end.

• Bodes well for future spectroscopy studies at the big

detectors!

62

SLIDE 63

Charmed baryon spectroscopy

• ... is very interesting these days, but since it's neither

"b-hadrons" nor "CKM" I had better move right along.

63

SLIDE 64

Summary

• Exciting times!
• Much going on; much to do.
• Much attention focused on lepton anomalies right now
• If confirmed, we have another revolution on our hands!
• ... but first we have to see if they are confirmed.
• But we should not forget the rest of the programme:
• If anomalies are real, underlying NP will surely manifest in other places


=> look for other signs with more flavour physics

• If anomalies confirmed, next task will be to understand that NP


=> need more information & constraints => more flavour physics

• If anomalies not confirmed: back to business! More flavour physics.
• For me, key question is: if this is real, what other effects does it

imply we'll see? Where should we look for them?

• I look forward to hearing answers on Friday morning!

64

SLIDE 65

65

SLIDE 66

66

˜ t

SLIDE 67

CKM physics at hadron colliders

• What do we mean by "CKM physics"?
• Immediate answer: physics sensitive to the CKM matrix

67

SLIDE 68

CKM physics at hadron colliders

• What do we mean by "CKM physics"?
• Immediate answer: physics sensitive to the CKM matrix
• ... but that's both too broad and too narrow.
• e.g. you don't want to hear about BF measurements of SCS decays
• e.g. you do want to hear about lepton flavour universality tests

68

SLIDE 69

CKM physics at hadron colliders

• What do we mean by "CKM physics"?
• Immediate answer: physics sensitive to the CKM matrix
• ... but that's both too broad and too narrow.
• e.g. you don't want to hear about BF measurements of SCS decays
• e.g. you do want to hear about lepton flavour universality tests
• What we really mean is: (roughly)

flavour physics
 that lets us make serious, indirect tests of the SM
 either by itself


• r in combination with other measurements
• Other people are covering charm+kaons and


theory/pheno, so I'll focus on the b system.

69

SLIDE 70

LHCb results 2017/18

70

See: http://lhcbproject.web.cern.ch/lhcbproject/Publications/ LHCbProjectPublic/Summary_all.html (Too many to list here! 60 papers in 2017 and 30 in 2018, plus 5 CONF notes, plus some new results.)

SLIDE 71

CMS results 2017/18

• CKM:
• arXiv:1806.00636: Angular analysis of the decay B+ → K+𝜈+𝜈− in proton-proton collisions at sqrt(s)

= 8 TeV

• Phys. Rev. D 97, 072010 (2018): Measurement of the 𝛭b polarization and angular parameters in 𝛭b →

J/𝜔 𝛭 decays from pp collisions at sqrt(s) = 7 and 8 TeV

• Eur. Phys. J. C 78 (2018) 457: Measurement of b hadron lifetimes in pp collisions at sqrt(s) = 8 TeV
• Phys. Lett. B 781 (2018) 517: Measurement of angular parameters from the decay B0 → K*0𝜈+𝜈− in

proton-proton collisions at sqrt(s) = 8 TeV

• Non-CKM:
• Phys. Rev. Lett. 121 (2018) 092002: Observation of the 𝜓b1(3P) and 𝜓b2(3P) and measurement of

their masses

• Phys. Rev. Lett. 120, 202005 (2018): Search for the X(5568) state decaying into Bsπ± in proton-

proton collisions at sqrt(s) = 8 TeV

• Phys. Lett. B 780 (2018) 251: Measurement of quarkonium production cross sections in pp collisions

at sqrt(s) = 13 TeV

• CMS-PAS-BPH-13-002: Measurement of production cross sections times branching fraction of Bc+

→ J/𝜔 π+ and B+ → J/𝜔 K+ in pp collisions at sqrt(s) = 7 TeV at CMS

• CMS-PAS-BPH-16-003: Observation of the Bs2*(5840)0 → B0KS decay and studies of excited Bs

mesons in proton-proton collisions at sqrt(s) = 8 TeV

• See also:
• CMS-DP-2018-036: Heavy Flavour distributions from CMS with 2018 data at √s = 13 TeV
• CMS-DP-2018-014: 2017 B-Physics trigger efficiencies

71

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsBPH

SLIDE 72

ATLAS results 2017/18

• "CKM":
• ATL-PHYS-PUB-2018-005: Prospects for the ℬ(B(s) → 𝜈+𝜈−) measurements

with the ATLAS detector in the Run 2 and HL-LHC data campaigns

• arXiv:1805.04000: Angular analysis of B0 → K*𝜈+𝜈− decays in pp collisions at

sqrt(s) = 8 TeV with the ATLAS detector

• Non-"CKM":
• Phys. Rev. Lett. 120 (2018) 202007: Search for a Structure in the Bsπ±

Invariant Mass Spectrum with the ATLAS Experiment

• Eur. Phys. J. C 78 (2018) 171: Measurement of quarkonium production in

proton-lead and proton-proton collisions at 5.02 TeV with the ATLAS detector

• JHEP 11 (2017) 62: Measurement of b-hadron pair production with the

ATLAS detector in proton-proton collisions at sqrt(s) = 8 TeV

72

https://twiki.cern.ch/twiki/bin/view/AtlasPublic/BPhysPublicResults

SLIDE 73

D0 results 2017/18

• Non-CKM:
• arXiv:1807.00183: Evidence for Zc(3900)± in semi-inclusive

decays of b-flavored hadrons

• Phys. Rev. D 97, 092004 (2018): Study of the X(5568)± state

with semileptonic decays of the Bs meson

73

https://www-d0.fnal.gov/d0_publications/d0_pubs_list_runII_bytopic_byyear.html#b

SLIDE 74

CDF results 2017/18

• Non-CKM:
• Phys. Rev. Lett. 120, 202006 (2018): A search for the exotic

meson X(5568) with the Collider Detector at Fermilab

74

https://www-cdf.fnal.gov/physics/new/bottom/bottom.html

SLIDE 75

Other studies

75

PRL 119, 181807 (2017)

Search for baryon-number-violating oscillations: Tag initial state via decay of narrow resonances: Fit same-sign/opposite-sign ratio
 as function of decay time => limit on oscillation rate 𝜐mix > 13 ps @ 95% CL Ξ0

b → Ξ0 b

]

2

c [MeV/ m δ

10 20 30 40

2

c Entries / 0.5 MeV/

20 40 60 80 100 120 140 OS SS

]

2

c [MeV/ m δ

2 3 4 5

2

c Entries / 0.1 MeV/ 5 10 15 20 25 30 35

LHCb

Ξ′−

b , Ξ*0 b → Ξ0 bπ−

Run1

SLIDE 76

TD CPV in Bs → Ds∓ K±

• Interference between mixing & decay


=> sensitive to (𝛿−2𝛾s)

• Fit in two stages:
• Fit to obtain signal weights (Bs mass, Ds mass, PID)
• Flavour-tagged, time-dependent sFit
• Calibration/control mode: Bs -> Ds pi
• 76

JHEP 03 (2018) 059

Vcb × V ∗

us ≈ λ3

B0

s

K− D+

s

b s s u c s

V ∗

ub × Vcs ≈ λ3

B0

s

D+

s

K b u, c, t W ⌥ W ± u, c, t s b s c u s

5300 5400 5500 5600 5700 5800 BeautyMass 200 400 600 800 1000 1200 )

2

c Candidates / ( 5.00 MeV/

Data Total fit

±

K

± s

D →

s

B Signal

±

) * (

K

±

) * (

s

D →

(d,s)

B )

+

ρ ,

+

π (

−

) * (

s

D →

s

B )

±

π ,

±

K (

±

D →

d

B p

−

) * (

s

D →

b

Λ )

+

π ,

+

K (

− c

Λ →

b

Λ Combinatorial

LHCb

5300 5400 5500 5600 5700 5800 ]

2

c ) [MeV/

+

K

−

s

m(D 2 − 2

0.1 0.2 0.3 ) [ps]

s

m Δ / π ) modulo (2

+

K

− s

D →

s

B ( t 0.4 − 0.2 − 0.2 0.4

)

+

K

s −

D (

mix

A

LHCb

0.1 0.2 0.3 ) [ps]

s

m Δ / π ) modulo (2

−

K

+ s

D →

s

B ( t 0.4 − 0.2 − 0.2 0.4

)

−

K

s +

D (

mix

A

LHCb

SLIDE 77

TD CPV in Bs → Ds∓ K±

77

JHEP 03 (2018) 059

Parameter Value Cf 0.730 ± 0.142 ± 0.045 A∆Γ

f

0.387 ± 0.277 ± 0.153 A∆Γ

f

0.308 ± 0.275 ± 0.152 Sf −0.519 ± 0.202 ± 0.070 Sf −0.489 ± 0.196 ± 0.068

+ phi_s:

], s = −0.030±0.033 rad,

= (128 +17

22) ,

= (358 +13

14) ,

rDsK = 0.37 +0.10

0.09 ,

Fit results External input Compatible at 2.3sigma with LHCb avg for gamma

SLIDE 78

TD CPV in B0 → D∓ π±

• Similar story: interference between mixing & decay


=> sensitive to (𝛿+2𝛾)

78

JHEP 06 (2018) 084

]

2

c mass [MeV/

±

π

±

D

5100 5200 5300 5400 5500 5600 5700 5800 5900 6000

)

2

c Candidates/(4.0 MeV/

5 10 15 20 25 30 35 40 45

3

10 ×

LHCb Data Total

±

K

±

D → B

±

π

±

D → B ρ

±

D → B Combinatorial

±

π

± *

D → B

]

2

c mass [MeV/

±

K

±

D

5100 5200 5300 5400 5500 5600 5700 5800 5900 6000

)

2

c Candidates/(4.0 MeV/

500 1000 1500 2000 2500 3000 3500

LHCb Data Total

±

K

±

D → B

±

π

±

D → B ρ

±

D → B Combinatorial

±

π /

±

) * (

K

±

) * (

D → B

Decay time [ps]

5 10

)

F

A Signal yield asymmetry (

0.2 − 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 0.2 0.25

LHCb

Decay time [ps]

5 10

)

S

A Signal yield asymmetry (

0.2 − 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 0.2 0.25

LHCb

| sin(2 + )| ∈ [0.77, 1.0] , ∈ [5, 86] ∪ [185, 266] , ∈ [−41, 41] ∪ [140, 220] ,

] ° [ γ CL − 1

0.2 0.4 0.6 0.8 1

] ° [ γ

100 200 300 68.3% 95.5%

LHCb ] ° [ γ ] ° [ δ ] ° [ γ

100 200 300

] ° [ δ

100 200 300

LHCb

39, 87% CL

SLIDE 79

Mass (MeV)

6000 6400 6800 7200 7600

1S0

6271 6338 6855 6887 6706 7250 7272 7122 6741 6750 7145 7150 6768 7164 7572 7588 7455 7472 7475 7487 7028 7365 7036 7041 7372 7376 7045 7380 7269 7565 7271 7568 7266 7276 7563 7571

3S1 3P0 P1 3P2 3D1 D2 3D3 3F2 F3 3F4

Bc Mass Spectrum 1-

Excited Bc+ states

• Expect two structures in Bc+ π+ π−:
• Bc(21S0)+ → Bc+ π+ π−
• Bc(23S1)+ → Bc*+ π+ π−, Bc*+ → Bc+ γ
• Higher production rate of Bc(23S1)+
• Bc(21S0)+ peak at its mass,


predicted to be ~ [6830,6890] MeV

• Bc(23S1)+ peak offset from its true mass


by missing photon; separation between the two peaks is





and is predicted to be [0, 35] MeV

• So ATLAS may be seeing
• Just Bc(21S0)+
• Just Bc(23S1)+ with missing photon
• Mixture of Bc(21S0)+ and Bc(23S1)+

79

∆M ≡ ⇥ M(B∗+

c ) − M(B+ c )

⇤ − ⇥ M(B∗

c(2S)+) − M(Bc(2S)+)

⇤ ,

Gershtein et al., Sov. J. Nucl. Phys. 48, 327 (1988)
 Chen & Kuang, PRD 46, 1165 (1992)
 Eichten & Quigg, PRD 49, 5845 (1994) Kiselev et al, PRD 51, 3613 (1995)
 Gupta & Johnson, PRD 53, 312 (1996) Fulcher, PRD 60, 074006 (1999) Ebert et al, PRD 67, 014027 (2003) Godfrey, PRD 70, 054017 (2004) Wei & Guo, PRD 81, 076005 (2010) Rai & Vinodkumar, Pramana 66, 953 (2006)
 Abd El-Hady et al, PRD 71, 034006 (2005) Gouz et al, Phys.Atom.Nucl. 67, 1559 (2004); Yad.Fiz. 67, 1581 (2004) Godfrey, PRD 70, 054017 (2004)

SLIDE 80

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

50 100 150 200 250 300 350

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

20 40 60 80 100 120

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

10 20 30 40 50 60

1 −

LHCb 2 fb = 8 TeV s

]

2

c ) [MeV/

−

π

+

π

+ c

B ( M

6600 6800 7000 7200

)

2

c Candidates / (28 MeV/

5 10 15 20 25 30 35 40 45

1 −

LHCb 2 fb = 8 TeV s

WS in green

Excited Bc+ states

80 LHCb: JHEP (2018) 2018: 138

add π+ π−

]

2

c ) [MeV/

+

π ψ / J ( M

6200 6300 6400 6500

)

2

c Candidates / (8 MeV/

100 200 300 400 500 600 700 800 900

Data Total fit

+

π ψ / J →

+ c

B

+

K ψ / J →

+ c

B Combinatorial

1 −

LHCb 2 fb = 8 TeV s

In 2017: LHCb doesn't confirm the observation with a larger Bc+ sample

Bc+ → J/ψ π+ (3325 ± 73)

Bins of MVA classifier output m(Bc+ π+ π−)

• UL on yield ratio (resonance/Bc+) set as function

• f mass for different hypotheses, see backups.
• LHCb & ATLAS results in mild tension but not


incompatible given uncertainties & different
 kinematics, efficiencies (low vs high pT).

• LHC experiments should be able to clear this up with Run2 data.

⟵ Increasing expected purity Bc+