Discussion on: Flavour Physics, CP violation and related matters - - PowerPoint PPT Presentation

S.Monteil Flavours 1

Discussion on: Flavour Physics, CP violation and related matters Working Group 6.

• S. Monteil,

LPC – Université Blaise Pascal – IN2P3-CNRS,

FCC kick-off meeting - Geneva - February 2014

S.Monteil Flavours 2

FCC kick-off meeting - Geneva - February 2014

Outline of the presentation

• 1. CKM, CPV, KM paradigm, NP signatures: a state of the art.
• 2. Foreseeable experimental landscape at horizon 2030.
• 3. Scope of the WG - some words on a possible method.
• 4. Conclusion.

S.Monteil Flavours 3

FCC kick-off meeting - Geneva - February 2014

Disclaimers

• 1. The WG will be installed a bit later than the others, at the

end of this Spring.

• 2. Not much time to prepare this talk but it was thought useful

however to be part of the discussion already now.

• 3. The scope of this talk is very modest, certainly not aiming at

a review of the subject or the observables of interest. Sharing few ideas instead to trigger discussion.

• 4. Full bias towards beautiful laboratories for today.
• 5. Disclaimers are richer than the actual outline.

S.Monteil Flavours 4

• 1. Flavour Physics and CP violation: a (rapid) state of the art.
• This is a tremendous success of the

Standard Model (SM) and especially the Kobayashi-Maskawa (KM)

• mechanism. This is simultaneously an
• utstanding experimental achievement

by the B- factories experiments.

• CKM is at work in weak charged

current transitions.

• The KM phase IS the dominant source
• f CP violation in K and B system.
• The second pillar of the SM.
• Experimental landscape so far

dominated by B-factories inputs.

S.Monteil Flavours 5

• 1. Flavour Physics and CP violation: a (rapid) state of the art.
• Since the SM hypothesis passes the global consistency test, metrology of its

free parameters is possible and predictions can be made → null tests of the SM hypothesis.

• A selection of two of the most remarkable achievements at LHC experiments

are given in the following. Starting with a ΔB = 2 process.

sin 2βs = 0.0367 ± 0.0014.

βs = − arg(−VcsV ∗

cb

VtsV ∗

tb

).

0.25 CDF LHCb ATLAS Combined SM 0.20 0.15 0.10 0.05 0-1.5

• 1.0
• 0.5

0.0 0.5 1.0 1.5 68% CL contours ( )

HFAG

PDG 2013

LHCb 1.0 fb

— 1+ CDF 9.6 fb — 1

+ ATLAS 4.9 fb

1

+ D 8 fb

— — 1

D

S.Monteil Flavours 6

• 1. Flavour Physics and CP violation: a (rapid) state of the art.
• Since the SM hypothesis passes the global consistency test, metrology of its

free parameters is possible and predictions can be made → Null tests of the SM hypothesis.

• Continuing with a ΔB = 1 process measured at CMS and LHCb.
• Phys. Rev. Lett. 111,

B(B0

s → µ+µ−)

= (2.9+1.1

−1.0) × 10−9,

B(B0 → µ+µ−) < 7.4 × 10−10 @ 95% CL.

S.Monteil Flavours 7

• 1. Flavour Physics and CP violation: a (rapid) state of the art.
• The flavour sector of the SM is so far successful.
• Flavour transitions and in particular Flavour Changing Neutral Currents

such as the two former illustrations are nicely accounted for in the SM while they are probing short distances physics sensitive to high mass scale.

• The flavour sector of the SM is too successful for the NP to be of generic

flavour structure.

• That, in turn, constrains the flavour structure of models beyond SM.
• Flavour is then part of our problem and maybe Flavour Physics is part of

the solution.

• Definitely interesting to scrutinize in the FCC context.

S.Monteil Flavours 8

• 2. Foreseeable experimental landscape at horizon 2030.
• Initial question addressed to the WG: is there a Physics case for flavour Physics

with O(1012) Z bosons, at the horizon of 2030?

• There are two experimental programs on track for flavour Physics starting in a

very near future: the LHCb upgrade and the Belle II project.

• The interest of O(1012) Z bosons for FP must be studied with respect to the

foreseeable legacy of those two programs.

• Some predictions of observables are currently limited by the theoretical

uncertainty on hadronic parameters. The progresses of LQCD in particular should be another dimension of the thinking.

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• 2. Foreseeable experimental landscape at horizon 2030.
• LHCb: this experiment has proven that

precision Flavour Physics can be undergone at a proton collider machine, despite the a priori harsh experimental

• environment. A solid ground to think that

its upgrade must be successful.

• The LHCb upgrade Physics case is

defined and expected performance are

• evaluated. Legacy statistics expected to

be O(50) /fb.

• All species of heavy flavour particles are

produced with very large statistics.

precision measurement 2013

decay time [ps]

1 2 3 4 candidates / (0.1 ps) 200 400

Tagged mixed Tagged unmixed Fit mixed Fit unmixed

LHCb

New J. Phys. 15 (2013) 053021 (1 fb−1)

An exemple of precision physics. Can be directly included in any HEP textbook.

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• 2. Foreseeable experimental landscape at horizon 2030.
• The LHCb upgrade Physics case is defined and expected performance are
• evaluated. Legacy statistics expected to be O(50) /fb.

Type Observable Current LHCb Upgrade Theory precision 2018 (50 fb−1) uncertainty B0

s mixing

2βs (B0

s → J/ψ φ)

0.10 [30] 0.025 0.008 ∼ 0.003 2βs (B0

s → J/ψ f0(980))

0.17 [32] 0.045 0.014 ∼ 0.01 as

sl

6.4 × 10−3 [63] 0.6 × 10−3 0.2 × 10−3 0.03 × 10−3 Gluonic 2βeff

s (B0 s → φφ)

– 0.17 0.03 0.02 penguins 2βeff

s (B0 s → K∗0 ¯

K∗0) – 0.13 0.02 < 0.02 2βeff(B0 → φK0

S)

0.17 [63] 0.30 0.05 0.02 Right-handed 2βeff

s (B0 s → φγ)

– 0.09 0.02 < 0.01 currents τ eff(B0

s → φγ)/τB0

s

– 5 % 1 % 0.2 % Electroweak S3(B0 → K∗0µ+µ−; 1 < q2 < 6 GeV2/c4) 0.08 [64] 0.025 0.008 0.02 penguins s0 AFB(B0 → K∗0µ+µ−) 25 % [64] 6 % 2 % 7 % AI(Kµ+µ−; 1 < q2 < 6 GeV2/c4) 0.25 [9] 0.08 0.025 ∼ 0.02 B(B+ → π+µ+µ−)/B(B+ → K+µ+µ−) 25 % [29] 8 % 2.5 % ∼ 10 % Higgs B(B0

s → µ+µ−)

1.5 × 10−9 [4] 0.5 × 10−9 0.15 × 10−9 0.3 × 10−9 penguins B(B0 → µ+µ−)/B(B0

s → µ+µ−)

– ∼ 100 % ∼ 35 % ∼ 5 % Unitarity γ (B → D(∗)K(∗)) ∼ 10–12◦ [40,41] 4◦ 0.9◦ negligible triangle γ (B0

s → DsK)

– 11◦ 2.0◦ negligible angles β (B0 → J/ψ K0

S)

0.8◦ [63] 0.6◦ 0.2◦ negligible Charm AΓ 2.3 × 10−3 [63] 0.40 × 10−3 0.07 × 10−3 – CP violation ∆ACP 2.1 × 10−3 [8] 0.65 × 10−3 0.12 × 10−3 – Table 1: Statistical sensitivities of the LHCb upgrade to key observables. For each observable the current sensitivity is compared to

that which will be achieved by LHCb before the upgrade, and that which will be achieved with 50 fb−1 by the upgraded experiment. Systematic uncertainties are expected to be non-negligible for the most precisely measured quantities. Note that the current sensitivities do not include new results presented at ICHEP 2012.

Eur.Phys.J. C73 (2013) 2373

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• 2. Foreseeable experimental landscape at horizon 2030.

Observable Belle 2006 SuperKEKB (∼0.5 ab−1) (5 ab−1) (50 ab−1) ( Hadronic b → s transitions ∆SφK0 0.22 0.073 0.029 ∆SηK0 0.11 0.038 0.020 ∆SK0

SK0 SK0 S

0.33 0.105 0.037 ∆Aπ0K0

S

0.15 0.072 0.042 AφφK+ 0.17 0.05 0.014 φeff

1

(φKS) Dalitz 3.3◦ 1.5◦ Radiative/electroweak b → s transitions SK0

Sπ0γ

0.32 0.10 0.03 B(B → Xsγ) 13% 7% 6% ACP (B → Xsγ) 0.058 0.01 0.005 C9 from AFB(B → K∗+−)

• 11%

4% C10 from AFB(B → K∗+−)

• 13%

4% C7/C9 from AFB(B → K∗+−)

• 5%

RK 0.07 0.02 B(B+ → K+νν)

†† < 3 BSM

30% B(B0 → K∗0ν¯ ν)

†† < 40 BSM

35%

B → Leptonic/semileptonic B decays B(B+ → τ +ν) 3.5σ 10% 3% B(B+ → µ+ν)

†† < 2.4BSM

4.3 ab−1 for 5σ discovery B(B+ → Dτν)

• 8%

3% B(B0 → Dτν)

• 30%

10% LFV in τ decays (U.L. at 90% C.L.) B(τ → µγ) [10−9] 45 10 5 B(τ → µη) [10−9] 65 5 2 B(τ → µµµ) [10−9] 21 3 1 Unitarity triangle parameters sin 2φ1 0.026 0.016 0.012 φ2 (ππ) 11◦ 10◦ 3◦ φ2 (ρπ) 68◦ < φ2 < 95◦ 3◦ 1.5◦ φ2 (ρρ) 62◦ < φ2 < 107◦ 3◦ 1.5◦ φ2 (combined) 2◦ 1◦ φ3 (D(∗)K(∗)) (Dalitz mod. ind.) 20◦ 7◦ 2◦ φ3 (DK(∗)) (ADS+GLW)

• 16◦

5◦ φ3 (D(∗)π)

• 18◦

6◦ φ3 (combined) 6◦ 1.5◦ |Vub| (inclusive) 6% 5% 3% |Vub| (exclusive) 15% 12% (LQCD) 5% (LQCD)

†††¯

ρ 20.0% 3.4%

• Belle II @ SUPERKEKB: will increase the B-factories statistics from O(1) to O

(50) /ab.

• The Belle II Physics case is defined and expected performance are evaluated

(arXiv 1002.5012). Coherent B0 mesons production at Υ(4s). A Lepton Flavour Violation and a Bs program.

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• 2. Foreseeable experimental landscape at horizon 2030
• A rapid comparison of yields in between FCC-ee, Belle II and LHCb upgrade on
• bvious processes gives (These estimates account for a luminosity of 5.6 1035

cm-2.s-1, b-quark hadronisation fractions as measured at LEP and large reconstruction efficiencies):

• O(150) Bs → μμ similar to LHCb.
• O(20) Bd → μμ same comment in order.
• O(few 1010) ττ , yielding equivalent sensitivity as Belle II for LFV processes

such as τ → eγ, μγ, eee, μμμ.

• The similarity of these yields triggers 2 thoughts for the FP case of the FCC-ee:
• relies on the specificity of the environment (low occupancy w.r.t LHCb, large

boost w.r.t Belle II).

• can bring cross-checks at the places where unique measurements are
• performed. Of utmost importance in case a new signal shows up in there.

S.Monteil Flavours 13

• 3. Scope of the working group.
• Evaluate the expected precision on the “obvious” observables of b-, c- and τ- Physics.
• It most likely requires to check the complementarity and the cross-section w/ the anticipated

achievements at LHCb upgrade and Belle II.

• Identify the key observables where this machine can contribute, either to global consistency

checks or null tests of the SM hypothesis.

• New ideas of measurements might come up.
• A way to quantify the performance and impact: since one wants to learn about short distance

physics, it can be driven imho by global fits of observables in presence of New Physics. I choose one model-independent approach to corner NP in mixing processes for the sake of discussion (other bottom-up approaches co-exist: Wilson coefficient fits, Constrained Minimal Flavour Violation ...)

• Founding papers: Soares & Wolfenstein, PRD 47,1021 (1993), Deshpande, Dutta & Oh,

PRL77, 4499 (1996), Goto et al., PRD53 6662 (1996), Silva & Wolfestein, PRD 55, 5331 (1997), Cohen et al., PRL 78,2300 (1997), Grossman, Nir & Worah, PLB 407, 307 (1997).

• For recent updates: UTFit M. Bona et al. [UTfit Collaboration], JHEP 0603, 080 (2006);

JHEP 0803, 049 (2008), A. Lenz et al. PRD83:036004.

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• 3. Scope of the working group.
• Sketch of the method (in large class of models)
• CKM unitarity still stands.
• NP in mixing processes can be

accounted for by means of new phase and modulus (NP) both in Bd and Bs system as defined below.

• No NP in b → f1f2f3
• Mixing observables are hence transforming

as described on the right. The apex of the triangle is basically fixed by |Vub| and γ angle.

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• 3. Scope of the working group.

Followed in arXiv:1309.2293 (Charles, Descotes, Ligeti et al.). Any NP choice would receive arbitrariness. Choose instead consistency w/ SM and derive eventually the minimal NP energy scale which has been proven given an hypothesis on the NP couplings.

• NP constraints in (h, σ) parametrization. h = amplitude of NP contribution.
• First, fixing the apex of the Triangle: past and prospects.

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• 3. Scope of the working group.
• NP parameters constraints: Bs as an illustration
• Minimal NP energy scale:

Couplings NP loop Scales (in TeV) probed by

• rder

Bd mixing Bs mixing |Cij| = |VtiV ∗

tj| tree level

17 19 (CKM-like)

• ne loop

1.4 1.5 |Cij| = 1 tree level 2 × 103 5 × 102 (no hierarchy) one loop 2 × 102 40

The additional constraints that the FCC-ee experiments would bring in this anticipated landscape is an invaluable input to the study imho.

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• 4. Summary
• In order to draw a realistic flavour physics case for O(1012) Z boson decays at

horizon 2030, we must compare with the anticipated legacy of flagship measurements of both Belle II and LHCb upgrade experiments.

• Generic NP (almost model-independent) scenarii to treat globally the observables

is a valuable mean to assess the potential of the machine and experiments.

• Identify the specific area where new information can be brought. But not only,

distinguish the areas where unique cross-checks can exist.

• Should an appealing case emerges for flavour Physics, sort out the detector

implications (most likely there, the opportunity of dedicated PID apparatus). I guess that the excellence of vertexing, finding electrons and muon in jets, tracking taus in calorimeters etc... are already implied by EW precision measurements.

• Working group activity to be installed at the end of Spring. Sign-up for interest to

the WG activity to be shortly available.

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• 3. Scope of the working group.
• NP parameters constraints: Bd

The additional constraints that the FCC-ee experiments would bring in this anticipated landscape is an invaluable input imho.