High Luminosity/High Energy LHC perspectives on Taus Emilie - - PowerPoint PPT Presentation
High Luminosity/High Energy LHC perspectives on Taus Emilie Passemar Indiana University/Jefferson Laboratory HL/HE LHC meeting Fermilab, April 5, 2018 Emilie Passemar Outline : 1. Introduction and Motivation: 2. Lepton Flavour Violation 3.
Emilie Passemar
Emilie Passemar Indiana University/Jefferson Laboratory HL/HE LHC meeting Fermilab, April 5, 2018
1. Introduction and Motivation: 2. Lepton Flavour Violation 3. Other interesting topics with tau decays 4. Conclusion and outlook
Emilie Passemar
(unexpected) success of the Standard Model: a successful theory of microscopic phenomena with no intrinsic energy limitation
search strategy given lack of clear indications on the SM-EFT boundaries (both in energies and effective couplings)
3 Emilie Passemar
b → c charged currents:
τ vs. light leptons (µ, e) [R(D), R(D*)]
Emilie Passemar
(unexpected) success of the Standard Model: a successful theory of microscopic phenomena with no intrinsic energy limitation
search strategy given lack of clear indications on the SM-EFT boundaries (both in energies and effective couplings)
4 Emilie Passemar
Key unique role of Tau physics
b → c charged currents:
τ vs. light leptons (µ, e) [R(D), R(D*)]
bL cL
W
τL , ℓL
νL
bL cL
τL
νL
NP
Emilie Passemar
very high scale: – Kaon physics: – Tau Leptons:
BaBar, Belle, BESIII, LHCb important
improvements on measurements and bounds
CMS)
e.g., LFV, EDMs
hadronic uncertainties essential, e.g. CPV in hadronic Tau decays
sdsd Λ2 ⇒ Λ 105 TeV µeff Λ2 ⇒ Λ 103 TeV
[τ → µγ] [εK]
E ΛNP ΛLE Tau leptons very important to look for New Physics!
5 4 2
τµ
before important experimental efforts from
LEP, CLEO, B factories: Babar, Belle, BES, VEPP-2M, LHCb, neutrino experiments,…
More to come from LHCb, BES,
VEPP-2M, Belle II, CMS, ATLAS, HL/HI LHC
“unexplored frontiers” deserve future exp. & th. efforts
Experiment Number of τ pairs LEP ~3x105 CLEO ~1x107 BaBar ~5x108 Belle ~9x108 Belle II ~1012 6 Emilie Passemar
Muon LFC µ → µγ (g − 2)µ, (EDM)µ νe ↔ νµ νµ ↔ ντ νe ↔ ντ NeutrinoOscillations τ → ℓγ τ → ℓℓ+
i ℓ− j
Tau LFV Tau LFC τ → τγ (g − 2)τ, (EDM)τ Muon LFV µ+ → e+γ µ+e− → µ−e+ µ−N → e+N′ µ−N → e−N µ+ → e+e+e− LFV
Adapted from Talk by
τ → ℓ + hadrons
Emilie Passemar 7
CPV in τ → Kπντ τ → Kππντ τ → Nπντ
Intensity Frontier Charged Lepton WG’13
due to GIM suppression unobservably small rates! E.g.:
Comparison in muonic and tauonic channels of branching raEos, conversion rates and spectra is model-diagnosEc
Emilie Passemar 9
µ → eγ
Br µ → eγ
( ) = 3α
32π U µi
* i=2,3
Uei Δm1i
2
MW
2 2
< 10−54
e, µ
µ,τ
Br τ → µγ
( ) < 10−40
⎡ ⎣ ⎤ ⎦
Petcov’77, Marciano & Sanda’77, Lee & Shrock’77…
channels
dependent
conversion rates and spectra is model-diagnostic
Emilie Passemar 10
Spring 2017
10−8 10−6
e
−γ µ
−γ e
−π µ
−π e
−K
Sµ
−K
Se
−η µ
−η e
−η′(958) µ
−η′(958) e
−ρ µ
−ρ e
−ω µ
−ω e
−K
∗(892) µ
−K
∗(892) e
−K
∗(892) µ
−K
∗(892) e
−φ µ
−φ e
−f (980) µ
−f (980) e
−e
+e
−e
−µ
+µ
−µ
−e
+µ
−µ
−e
+e
−e
−µ
+e
−µ
−µ
+µ
−e
−π
+π
−e
+π
−π
−µ
−π
+π
−µ
+π
−π
−e
−π
+K
−e
−K
+π
−e
+π
−K
−e
−K
SK
Se
−K
+K
−e
+K
−K
−µ
−π
+K
−µ
−K
+π
−µ
+π
−K
−µ
−K
SK
Sµ
−K
+K
−µ
+K
−K
−π
−Λ π
−Λ pµ
−µ
−pµ
+µ
−BaBar Belle CLEO LHCb
90% CL upper limits on τ LFV decays
Emilie Passemar
τ → ℓγ , τ → ℓ α ℓβℓ β , τ → ℓY
P, S, V, PP,...
11
Spring 2017
10−8 10−6
e
−γ µ
−γ e
−π µ
−π e
−K
Sµ
−K
Se
−η µ
−η e
−η′(958) µ
−η′(958) e
−ρ µ
−ρ e
−ω µ
−ω e
−K
∗(892) µ
−K
∗(892) e
−K
∗(892) µ
−K
∗(892) e
−φ µ
−φ e
−f (980) µ
−f (980) e
−e
+e
−e
−µ
+µ
−µ
−e
+µ
−µ
−e
+e
−e
−µ
+e
−µ
−µ
+µ
−e
−π
+π
−e
+π
−π
−µ
−π
+π
−µ
+π
−π
−e
−π
+K
−e
−K
+π
−e
+π
−K
−e
−K
SK
Se
−K
+K
−e
+K
−K
−µ
−π
+K
−µ
−K
+π
−µ
+π
−K
−µ
−K
SK
Sµ
−K
+K
−µ
+K
−K
−π
−Λ π
−Λ pµ
−µ
−pµ
+µ
−BaBar Belle CLEO LHCb
90% CL upper limits on τ LFV decays
Emilie Passemar
τ → ℓγ , τ → ℓ α ℓβℓ β , τ → ℓY
P, S, V, PP,...
12
Emilie Passemar 13
YEAR 1980 1990 2000 2010 2020
10
10
10
10
10 decays studied τ Approximate number of
5
10
6
10
7
10
8
10
9
10
10
10 MarkII ARGUS DELPHI CLEO Belle BaBar LHCb Belle II mSUGRA + seesaw SUSY + SO(10) SM + seesaw SUSY + Higgs
90% CL Upper Limit on Branching Ratio γ µ → τ η µ → τ µ µ µ → τ
B2TIP’18
Ø Dipole:
Emilie Passemar
L = LSM + C (5) Λ O(5) + Ci
(6)
Λ 2 Oi
(6) i
+ ...
14
See e.g. Black, Han, He, Sher’02 Brignole & Rossi’04 Dassinger et al.’07 Matsuzaki & Sanda’08 Giffels et al.’08 Crivellin, Najjari, Rosiek’13 Petrov & Zhuridov’14 Cirigliano, Celis, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν
τ
! τ
µ ! µ
e.g.
Ø Dipole: Ø Lepton-quark (Scalar, Pseudo-scalar, Vector, Axial-vector):
Emilie Passemar
L = LSM + C (5) Λ O(5) + Ci
(6)
Λ 2 Oi
(6) i
+ ...
See e.g. Black, Han, He, Sher’02 Brignole & Rossi’04 Dassinger et al.’07 Matsuzaki & Sanda’08 Giffels et al.’08 Crivellin, Najjari, Rosiek’13 Petrov & Zhuridov’14 Cirigliano, Celis, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν
Leff
S,V ⊃ −
CS,V Λ
2 mτmqGFµ ΓPL,Rτ qΓq
q q
τ
µ
ϕ ≡ h
0, H 0, A
e.g.
Γ ≡ 1
q q μ e
τ
µ
Γ ≡ γ µ
15
Ø Dipole: Ø Lepton-quark (Scalar, Pseudo-scalar, Vector, Axial-vector):
Ø Integrating out heavy quarks generates gluonic operator
Emilie Passemar
L = LSM + C (5) Λ O(5) + Ci
(6)
Λ 2 Oi
(6) i
+ ...
16
See e.g. Black, Han, He, Sher’02 Brignole & Rossi’04 Dassinger et al.’07 Matsuzaki & Sanda’08 Giffels et al.’08 Crivellin, Najjari, Rosiek’13 Petrov & Zhuridov’14 Cirigliano, Celis, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν Leff
S ⊃ −
CS,V Λ
2 mτmqGFµ ΓPL,Rτ qΓq
1 Λ 2 µPL,RτQQ
à
Leff
G ⊃ − CG
Λ
2 mτGFµPL,Rτ Gµν a Ga µν
q q
τ
µ
ϕ ≡ h0, H 0, A0
Ø Dipole: Ø Lepton-quark (Scalar, Pseudo-scalar, Vector, Axial-vector): Ø 4 leptons (Scalar, Pseudo-scalar, Vector, Axial-vector):
Emilie Passemar
L = LSM + C (5) Λ O(5) + Ci
(6)
Λ 2 Oi
(6) i
+ ...
17
See e.g. Black, Han, He, Sher’02 Brignole & Rossi’04 Dassinger et al.’07 Matsuzaki & Sanda’08 Giffels et al.’08 Crivellin, Najjari, Rosiek’13 Petrov & Zhuridov’14 Cirigliano, Celis, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν Leff
S ⊃ −
CS,V Λ
2 mτmqGFµ ΓPL,Rτ qΓq
Leff
4ℓ ⊃ − CS,V 4ℓ
Λ 2 µ ΓPL,Rτ µ ΓPL,Rµ Γ ≡ 1 ,γ µ
τ
µ µ µ
e.g.
Ø Dipole: Ø Lepton-quark (Scalar, Pseudo-scalar, Vector, Axial-vector): Ø Lepton-gluon (Scalar, Pseudo-scalar): Ø 4 leptons (Scalar, Pseudo-scalar, Vector, Axial-vector):
Emilie Passemar
L = LSM + C (5) Λ O(5) + Ci
(6)
Λ 2 Oi
(6) i
+ ...
18
See e.g. Black, Han, He, Sher’02 Brignole & Rossi’04 Dassinger et al.’07 Matsuzaki & Sanda’08 Giffels et al.’08 Crivellin, Najjari, Rosiek’13 Petrov & Zhuridov’14 Cirigliano, Celis, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν Leff
S ⊃ −
CS,V Λ
2 mτmqGFµ ΓPL,Rτ qΓq
Leff
G ⊃ − CG
Λ
2 mτGFµPL,Rτ Gµν a Ga µν
Leff
4ℓ ⊃ − CS,V 4ℓ
Λ 2 µ ΓPL,Rτ µ ΓPL,Rµ Γ ≡ 1 ,γ µ
Emilie Passemar
sensiEve to large number of operators!
form factors and decay constants (e.g. fη, fη’)
19
Celis, Cirigliano, E.P.’14
I=0 S-wave ππ and KK scaWering data as input
20
Celis, Cirigliano, E.P.’14 Celis, Cirigliano, E.P.’14 Daub et al’13 Donoghue, Gasser, Leutwyler’90 Moussallam’99 n = ππ , KK Hµ = ππ Vµ − Aµ
( )e
iLQCD 0 = Lorentz struct.
( )µ
i Fi s
( ) s =
pπ + + pπ −
( )
2
with
Emilie Passemar
Emilie Passemar
between operators and hence on the underlying mechanism
21
Celis, Cirigliano, E.P.’14
Ø Branching ratios: with FM dominant LFV mode for model M Ø Spectra for > 2 bodies in the final state:
Ø Dipole model: CD ≠ 0, Celse= 0 Ø Scalar model: CS ≠ 0, Celse= 0 Ø Vector (gamma,Z) model: CV ≠ 0, Celse= 0 Ø Gluonic model: CGG ≠ 0, Celse= 0
RF ,M ≡ Γ τ → F
( )
Γ τ → FM
( )
dBR τ → µµµ
( )
d s
22 Emilie Passemar
Ø Branching ratios: with FM dominant LFV mode for model M Benchmark
RF ,M ≡ Γ τ → F
( )
Γ τ → FM
( )
Celis, Cirigliano, E.P.’14
Emilie Passemar
Disentangle the underlying dynamics of NP
Buras et al.’10 ratio LHT MSSM (dipole) MSSM (Higgs) SM4
Br(µ−→e−e+e−) Br(µ→eγ)
0.02. . . 1 ∼ 6 · 10−3 ∼ 6 · 10−3 0.06 . . . 2.2
Br(τ −→e−e+e−) Br(τ→eγ)
0.04. . . 0.4 ∼ 1 · 10−2 ∼ 1 · 10−2 0.07 . . . 2.2
Br(τ −→µ−µ+µ−) Br(τ→µγ)
0.04. . . 0.4 ∼ 2 · 10−3 0.06 . . . 0.1 0.06 . . . 2.2
Br(τ −→e−µ+µ−) Br(τ→eγ)
0.04. . . 0.3 ∼ 2 · 10−3 0.02 . . . 0.04 0.03 . . . 1.3
Br(τ −→µ−e+e−) Br(τ→µγ)
0.04. . . 0.3 ∼ 1 · 10−2 ∼ 1 · 10−2 0.04 . . . 1.4
Br(τ −→e−e+e−) Br(τ −→e−µ+µ−)
0.8. . . 2 ∼ 5 0.3. . . 0.5 1.5 . . . 2.3
Br(τ −→µ−µ+µ−) Br(τ −→µ−e+e−)
0.7. . . 1.6 ∼ 0.2
1.4 . . . 1.7
R(µTi→eTi) Br(µ→eγ)
10−3 . . . 102 ∼ 5 · 10−3 0.08 . . . 0.15 10−12 . . . 26
24 Emilie Passemar
Figure 3:
Dalitz plot for τ − → µ−µ+µ− decays when all operators are assumed to vanish with the exception of CDL,DR = 1 (left) and CSLL,SRR = 1 (right), taking Λ = 1 TeV in both cases. Colors denote the density for d2BR/(dm2
µ−µ+dm2 µ−µ−), small values being represented by darker colors and
large values in lighter ones. Here m2
µ−µ+ represents m2 12 or m2 23, defined in Sec. 3.1.
Figure 4:
Dalitz plot for τ − → µ−µ+µ− decays when all operators are assumed to vanish with the exception of CVRL,VLR = 1 (left) and CVLL,VRR = 1 (right), taking Λ = 1 TeV in both cases. Colors are defined as in Fig. 3.
Dassinger, Feldman, Mannel, Turczyk’ 07 Celis, Cirigliano, E.P.’14 Angular analysis with polarized taus
Dassinger, Feldman, Mannel, Turczyk’ 07
25
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν
26 Emilie Passemar τ
! τ
µ ! µ
Celis, Cirigliano, E.P.’14
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν
Leff
S ⊃ − CS
Λ
2 mτmqGFµPL,Rτ qq
27 Emilie Passemar
Different distributions according to the operator!
Leff
D ⊃ − CD
Λ 2 mτ µσ µνPL,Rτ Fµν
Leff
S ⊃ − CS
Λ
2 mτmqGFµPL,Rτ qq
Leff
G ⊃ − CG
Λ
2 mτGFµPL,Rτ Gµν a Ga µν
28
In the SM:
v
SM
h i ij ij
m Y δ =
Yτµ Hadronic part treated with perturbaEve QCD
ΔL
Y = − λij
Λ 2 fL
i fR jH
( ) H †H
−Yij fL
i fR j
( )h
Goudelis, Lebedev, Park’11 Davidson, Grenier’10 Harnik, Kopp, Zupan’12 Blankenburg, Ellis, Isidori’12 McKeen, Pospelov, Ritz’12 Arhrib, Cheng, Kong’12
29 Emilie Passemar
In the SM:
v
SM
h i ij ij
m Y δ =
Yτµ Hadronic part treated with perturbaEve QCD
ΔL
Y = − λij
Λ 2 fL
i fR jH
( ) H †H
−Yij fL
i fR j
( )h
Goudelis, Lebedev, Park’11 Davidson, Grenier’10 Harnik, Kopp, Zupan’12 Blankenburg, Ellis, Isidori’12 McKeen, Pospelov, Ritz’12 Arhrib, Cheng, Kong’12
30 Emilie Passemar
Reverse the process Yτµ Hadronic part treated with non-perturbaEve QCD
Ø τ → µππ :
ρ f
Dominated by Ø ρ(770) (photon mediated) Ø f0(980) (Higgs mediated)
+
h h
31 Emilie Passemar Cirigliano, Celis, E.P.’14
Ø τ → µγ : best constraints
but loop level sensiEve to UV compleEon of the theory
Ø τ → µππ : tree level
diagrams robust handle on LFV
LHC wins for τ µ!
nothing else: LHC bound
BR τ → µγ
( ) < 2.2 ×10−9
BR τ → µππ
( ) < 1.5 ×10−11
|
τ µ
|Y
10
10
10
10 1
|
µ τ
|Y
10
10
10
10 1
(8 TeV)
19.7 fb
CMS
BR<0.1% BR<1% BR<10% BR<50%
τ τ → ATLAS H
expected τ µ → H
µ 3 → τ γ µ → τ
2
/ v
τ
m
µ
| = m
µ τ
Y
τ µ
| Y
Plot from Harnik, Kopp, Zupan’12 updated by CMS’15 τ → µππ ππ
33
|
τ µ
|Y
4 −
10
3 −
10
2 −
10
1 −
10 1
|
µ τ
|Y
4 −
10
3 −
10
2 −
10
1 −
10 1
(13 TeV)
2.3 fb
CMS Preliminary
BR<0.1% BR<1% BR<10% BR<50%
expected τ µ → H µ 3 → τ γ µ → τ
2
/v
τ
m
µ
|=m
µ τ
Y
τ µ
|Y
CMS’16 τ → µππ ππ
Emilie Passemar
34
CMS’17
Emilie Passemar
36 Emilie Passemar
37 Emilie Passemar
– W decay old anomaly – B decays
38 Emilie Passemar
1.0010 ± 0.0015
Updated with HFAG’17
0.9860 ± 0.0070 0.9961 ± 0.0027 1.0000 ± 0.0014 1.0029 ± 0.0015
Updated with HFAG’17
See talks in this morning Flavour session
39 Emilie Passemar
23/02/2005
W Leptonic Branching Ratios
ALEPH 10.78 ± 0.29 DELPHI 10.55 ± 0.34 L3 10.78 ± 0.32 OPAL 10.40 ± 0.35
LEP W→eν 10.65 ± 0.17
ALEPH 10.87 ± 0.26 DELPHI 10.65 ± 0.27 L3 10.03 ± 0.31 OPAL 10.61 ± 0.35
LEP W→µν 10.59 ± 0.15
ALEPH 11.25 ± 0.38 DELPHI 11.46 ± 0.43 L3 11.89 ± 0.45 OPAL 11.18 ± 0.48
LEP W→τν 11.44 ± 0.22
LEP W→lν 10.84 ± 0.09
χ2/ndf = 6.3 / 9 χ2/ndf = 15.4 / 11
10 11 12
Br(W→lν) [%]
Winter 2005 - LEP Preliminary
40 Emilie Passemar
23/02/2005
W Leptonic Branching Ratios
ALEPH 10.78 ± 0.29 DELPHI 10.55 ± 0.34 L3 10.78 ± 0.32 OPAL 10.40 ± 0.35
LEP W→eν 10.65 ± 0.17
ALEPH 10.87 ± 0.26 DELPHI 10.65 ± 0.27 L3 10.03 ± 0.31 OPAL 10.61 ± 0.35
LEP W→µν 10.59 ± 0.15
ALEPH 11.25 ± 0.38 DELPHI 11.46 ± 0.43 L3 11.89 ± 0.45 OPAL 11.18 ± 0.48
LEP W→τν 11.44 ± 0.22
LEP W→lν 10.84 ± 0.09
χ2/ndf = 6.3 / 9 χ2/ndf = 15.4 / 11
10 11 12
Br(W→lν) [%]
Winter 2005 - LEP Preliminary
Some models: Try to explain with SM EFT approach with [U(2)xU(1)]5 flavour symmetry Very difficult to explain without modifying any other observables
measurement by LHC 2.8σ away from SM!
Filipuzzi, Portoles, Gonzalez-Alonso'12 Li & Ma’05, Park’06, Dermisek’08
41 Emilie Passemar
0.21 0.21 0.22 0.22 0.23 0.23 0.24 0.24 0.25 0.25
Vus
τ -> Kν absolute (+ fK) τ -> Kπντ decays (+ f+(0), FLAG) τ branching fraction ratio Kl2 /πl2 decays (+ fK/fπ) τ -> s inclusive Our result from Belle BR τ decays Kaon and hyperon decays Kl3 decays (+ f+(0)) Hyperon decays τ -> Kν / τ -> πν (+ fK/fπ)
From Unitarity Flavianet Kaon WG’10 update by Moulson’CKM16 BaBar & Belle HFAG’17 NB: BRs measured by B factories are systemaEcally smaller than previous measurements
42
in extraction of Vus
δ Rτ ≡ Rτ ,NS Vud
2 − Rτ ,S
Vus
2
SU(3) breaking quantity, strong dependence in ms computed from OPE (L+T) + phenomenology δ Rτ ,th = 0.0242(32) Gamiz et al’07, Maltman’11
Vus
2 =
Rτ ,S Rτ ,NS Vud
2 −δ Rτ ,th
Rτ ,S = 0.1633(28) Rτ ,NS = 3.4718(84)
HFAG’17
Vud = 0.97417(21)
Vus = 0.2186 ± 0.0019exp ± 0.0010th 3.1σ away from unitarity!
0’
43
A
Q =
Γ τ + → π +KS
0ντ
( ) − Γ τ − → π −KS
0ντ
( )
Γ τ + → π +KS
0ντ
( ) + Γ τ − → π −KS
0ντ
( )
S
K p K q K = + = +
L
K p K q K = −
KL KS = p
2 − q 2 ! 2Re ε K
( )
2 2
=
q
( )
0.36 0.01 % ≈ ±
Bigi & Sanda’05
in the SM
Grossman & Nir’11
A
Qexp = -0.36 ± 0.23stat ± 0.11syst
( )%
2.8σ
from the SM!
BaBar’11 Grossman & Nir’11
AD = Γ D+ → π +KS
( ) − Γ D− → π −KS ( )
Γ D+ → π +KS
( ) + Γ D− → π −KS ( ) = -0.54 ± 0.14
( )%
Belle, Babar, CLEO, FOCUS
Emilie Passemar
interactions (Devi, Dhargyal, Sinha’14, Cirigliano, Crivellin, Hoferichter’17)?
models: it looks like a tensor interaction can explain the effect but in conflict with bounds from neutron EDM and DD mixing
light BSM physics? Bigi’Tau12
Very difficult to explain!
Emilie Passemar 44
Cirigliano, Crivellin, Hoferichter’17
45
vanish:
G’ is an imaginary coupling
5
'( )( (1 ) )
eff T
G s u
2 CT , with
0.00 0.05 0.10
0.00 0.05 0.10 Im[cT
21]
Im[cT
11]
In conflict with bounds from neutron EDM and DD mixing
2 2 2 V T SM T
d d d dQ dQ dQ d dQ
dQ2 = GF
2 sin2θC
mτ
3
32π 3 mτ
2 − Q2
mτ
2
⎛ ⎝ ⎜ ⎞ ⎠ ⎟
2
q1
3
Q2
( )
3/2
Q2 mτ
2
× CT F
V (s) F T (s) cos δT (s) − δV (s) + φT
( )
CT = CT e
iφT
nEDM D-D, =- /4 D-D, = /4 |ACP
,BSM|>10-3
τ u u τ c u τ u c
Devi, Dhargyal, Sinha’14
Cirigliano, Crivellin, Hoferichter’17 Cirigliano, Crivellin, Hoferichter’17
Emilie Passemar
CMS energy frontier
decipher possible TeV-scale new physics requires to work hard on the intensity and precision frontiers
Ø LFV measurement has SM-free signal Ø Several interesting anomalies: LFU, Vus, CPV in τ → Kπντ Ø Progress towards a better knowledge of hadronic uncertainties Ø New physics models usually strongly correlate the flavours sectors Ø Important experimental activities: Belle, BaBar, LHCb, ATLAS, CMS and more to come: Belle II, HL LHC, etc
Emilie Passemar 47
49 Emilie Passemar
e
e
5 2 2 R 3 C
( ) ( / ) 192 1
l
l
G m l f m m
Rates with well-determined
treatment of radiative decays
Γ τ l3
( )
Inputs from theory:
Radiative corrections
δ RC
Marciano’88
/ 0.9761 0.0028
e
B B
0.9725 0.0039 BaBar ‘10: 0.9796 0.0039
univ = (17.818 ± 0.0022)
Spring 2017
0.1770 0.1775 0.1780 0.1785 0.1790 289 290 291 292
ττ(fs) B ′(τ → eνν)
5 fi fi
SM lepton universality, 1 ←
Emilie Passemar 50
Belle’08’11’12 except last from CLEO’97
Bound:
Yµτ
h 2
+ Yτµ
h 2
≤ 0.13
Br(τ → eπ+π−) < 4.3 × 10−7, Br(τ → eπ0π0) < 2.1 × 10−7 Br(τ → µπ+π−) < 3.0 × 10−8, Br(τ → µπ0π0) < 1.5 × 10−8
but also to Yu,d,s!
below present experimental limits!
Interplay between high-energy and low-energy constraints!
Talk by J. Zupan @ KEK-FF2014FALL
Br(τ → eπ+π−) < 2.3 × 10−10, Br(τ → eπ0π0) < 6.9 × 10−11 Br(τ → µπ+π−) < 1.6 × 10−11, Br(τ → µπ0π0) < 4.6 × 10−12
Emilie Passemar
51
h h
Emilie Passemar
vector form factor:
52
ρ(770) ρ’(1465) ρ’’(1700)
following the properties of analyticity and unitarity
Gasser, Meißner ́91 Guerrero, Pich’97 Oller, Oset, Palomar ́01 Pich, Portolés ́08 Gómez Dumm&Roig’13 ...
to the Belle data on τ- → π-π0ντ
Celis, Cirigliano, E.P.’14
Ø Precisely known from experimental measurements Ø Theoretically: Dispersive parametrization for FV(s) Ø Subtraction polynomial + phase determined from a fit to the Belle data
53
e e π π π π
+ − + −
→
and (isospin rotation)
τ
τ π τ π π ν
− − − −
→
F
V (s) = exp λV '
s mπ
2 + 1
2 λV
'' − λV '2
( )
s mπ
2
" # $ $ % & ' '
2
+ s3 π ds' s'3 φV (s') s'− s − iε
( )
4mπ
2
∞
* + , ,
/ /
Extracted from a model including 3 resonances ρ(770), ρ’(1465) and ρ’’(1700) fitted to the data
Emilie Passemar
Guerrero, Pich’98, Pich, Portolés’08 Gomez, Roig’13
τ
τ π τ π π ν
− − − −
→
Emilie Passemar
Determination of FV(s) thanks to precise measurements from Belle!
ρ(770) ρ’(1465) ρ’’(1700)
54
( )
h q
f y
with the form factors:
Emilie Passemar
+
h h
55
Yτµ ✓µ
µ = 9↵s
8⇡Ga
µ⌫Gµ⌫ a +
X
q=u,d,s
mq¯ qq
s = pπ + + pπ −
2
Voloshin’85
up to √s ~1.4 GeV Inputs: I=0, S-wave ππ and KK data
Emilie Passemar
Donoghue, Gasser, Leutwyler’90 Moussallam’99
π π π π π π π π + π π
K K K K
Donoghue, Gasser, Leutwyler’90 Moussallam’99
n = ππ , KK
Daub et al’13
56
Buttiker et al’03, Garcia-Martin et al’09, Colangelo et al.’11 and all agree
Emilie Passemar 57
Garcia-Martin et al’09 Buttiker et al’03
Celis, Cirigliano, E.P.’14
starting with Omnès functions
Emilie Passemar
Polynomial determined from a matching to ChPT + lattice Canonical solution
X(s) = C(s), D(s)
58
Feynman-Hellmann theorem:
59
FP(s) →1/ s (Brodsky & Lepage)
Use lattice QCD to determine the SU(3) LECs
60
Bernard, Descotes-Genon, Toucas’12 Dreiner, Hanart, Kubis, Meissner’13
The unsubtracted DR is not saturated by the 2 states
Relax the constraints and match to ChPT
61
"σ " f f
Emilie Passemar 62
f
Emilie Passemar 63
"σ " f
It is not valid up to E = !
Emilie Passemar Emilie Passemar 64
– W decay old anomaly – B decays
65 Emilie Passemar
K K W W
e
B B B
0.9962 0.0027 0.9858 0.0070 1.034 0.013
g g
W
e
B B B
0.0015 1.031 0.013
e
g g
updated on HFAG’17
ud us
d V d V s
θ =
+ = +
Vud
τ ππ ππντ τ
πντ τ hNSντ
Vus
τ
Kπντ
τ
Kντ τ hSντ
(inclusive) Vud 0+ 0+
π± π0eνe
n peνe
π lνl
Vus K πlνl Λ peνe K lνl
Emilie Passemar 66
ud us
d V d V s
θ =
+ = +
Vud
τ ππ ππντ τ
πντ τ hNSντ
Vus
τ
Kπντ
τ
Kντ τ hSντ
(inclusive) Vud 0+ 0+
π± π0eνe
n peνe
π lνl
Vus K πlνl Λ peνe K lνl
Emilie Passemar 67
precision not only the total BRs but also the energy distribution of the hadronic system huge QCD activity!
Emilie Passemar
( )
, ud us
τ
τ ν τ ν →
α S mτ
( ), Vus , ms
( ) mτ ~ 1.77GeV > ΛQCD
Γ τ − → ντ + hadronsS=0
( )
Γ τ − → ντ + hadronsS≠0
( )
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
ud us
d V d V s
θ =
+ = +
Davier et al’13
68
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
(αS=0)
Vus
2
Vud
2 = Rτ S
Rτ
NS
Vus
ud us
d V d V s
θ =
+ = +
Figure from
69
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
1 3.6291 0.0086
e e
B B R B
µ τ
− − − − = = = = ±
(αS≠0)
ud us
d V d V s
θ =
+ = +
70
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
1 3.6291 0.0086
e e
B B R B
µ τ
− − − − = = = = ±
(αS≠0)
( )
2 2 ud C us C S
R V N V N
τ
α = + = + + Ο
ud us
d V d V s
θ =
+ = +
71
extraction of αS, |Vus|
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
(αS≠0)
Rτ
NS = Vud 2 NC + O α S
( )
measured calculated
S
α
Vus
2
Vud
2 = Rτ S
Rτ
NS + O α S
( )
ud us
d V d V s
θ =
+ = +
72
Cauchy Theorem
Emilie Passemar
Braaten, Narison, Pich’92
( ) (
)
( ) (
)
2
2 1 2 2 2 2
( ) 12 1 1 2 Im Im
m EW
ds s s R m S s i s i m m m
τ
τ τ τ τ τ τ τ τ τ
π ε π ε ε ⎡ ⎤ ⎡ ⎤ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ = − + Π + + Π + ⎢ ⎥ ⎢ ⎥ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎢ ⎥ ⎢ ⎥ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎣ ⎦ ⎣ ⎦
∫
Rτ (mτ
2) = 6iπ SEW
ds mτ
2 1 − s
mτ
2
⎛ ⎝ ⎜ ⎞ ⎠ ⎟
2
1 + 2 s mτ
2
⎛ ⎝ ⎜ ⎞ ⎠ ⎟ Π
1
( ) s
( ) + Π
( ) s
( )
⎡ ⎣ ⎢ ⎢ ⎤ ⎦ ⎥ ⎥
s =mτ
2
! ∫
( ) ( )
2 0,2,4... dim
1 ( ) ( , ) ( ) ( )
J J D D D O D
s s O s µ µ µ µ
= = = =
Π = −
∑ ∑ ∑ ∑ C
Wilson coefficients Operators
μ: separaEon scale between
short and long distances
73
Use of weighted distribuEons
Emilie Passemar
Braaten, Narison, Pich’92
( )
( )
2
1
C EW P NP
R m N S
τ τ τ τ
δ δ δ δ = + = + +
1.0201(3)
EW
S =
Marciano &Sirlin’88, Braaten & Li’90, Erler’04
2 3 4
5.20 26 127 ... 20%
P
a a a a
τ τ τ τ τ τ
δ = + = + + + + ≈
Baikov, Chetyrkin, Kühn’08
( )
s m
a
τ τ
α π =
( )
,
NS u d
R m m
τ
∝
( )
s S
R m
τ
∝
74
Use of weighted distribuEons Exploit shape of the spectral funcEons to obtain addiEonal experimental informaEon
Emilie Passemar
Le Diberder&Pich’92
( )
s S
R m
τ
∝
Rτ ≡ R00
τ
Zhang’Tau14
75
Vus
2
Vud
2 = Rτ S
Rτ
NS + O α S
( )
(αS≠0)
δ Rτ ≡ Rτ ,NS Vud
2 − Rτ ,S
Vus
2
Rτ
NS mτ 2
( ) = NC SEW Vud
2 1 + δ P + δ NP ud
( )
Rτ
S mτ 2
( ) = NC SEW Vus
2 1 + δ P + δ NP us
( )
Vus
2 =
Rτ ,S Rτ ,NS Vud
2 −δ Rτ ,th
SU(3) breaking quanEty, strong dependence in ms computed from OPE (L+T) + phenomenology
δ Rτ ,th = 0.0242(32)
Gamiz et al’07, Maltman’11
Rτ ,S = 0.1633(28) Rτ ,NS = 3.4718(84)
HFAG’17
Vud = 0.97417(21)
Vus = 0.2186 ± 0.0019exp ± 0.0010th 3.1σ away from unitarity!
Emilie Passemar 76
0.21 0.21 0.22 0.22 0.23 0.23 0.24 0.24 0.25 0.25
Vus
τ -> Kν absolute (+ fK) τ -> Kπντ decays (+ f+(0), FLAG) τ branching fraction ratio Kl2 /πl2 decays (+ fK/fπ) τ -> s inclusive Our result from Belle BR τ decays Kaon and hyperon decays Kl3 decays (+ f+(0)) Hyperon decays τ -> Kν / τ -> πν (+ fK/fπ)
From Unitarity Flavianet Kaon WG’10 update by Moulson’CKM16 BaBar & Belle HFAG’17
Emilie Passemar
NB: BRs measured by B factories are systemaEcally smaller than previous measurements
77
78
(0.471 ± 0.018)% (0.857 ± 0.030)% (2.967 ± 0.060)%
between τ and kaon decays in extraction of Vus
Recent studies
τ → Kπντ Br + spectrum
need new data Vus = 0.2229 ± 0.0022exp ± 0.0004theo
(0.471 ± 0.018)% (0.857 ± 0.030)% (2.967 ± 0.060)%
between τ and kaon decays in extraction of Vus
Recent studies
τ → Kπντ Br + spectrum
need new data
Vus = 0.2229 ± 0.0022exp ± 0.0004theo
|
us
|V
0.22 0.225 , PDG 2016
l3
K 0.0010 ± 0.2237 , PDG 2016
l2
K 0.0007 ± 0.2254 CKM unitarity, PDG 2016 0.0009 ± 0.2258 s incl., Maltman 2017 → τ 0.0004 ± 0.0022 ± 0.2229 s incl., HFLAV 2016 → τ 0.0021 ± 0.2186 , HFLAV 2016 ν π → τ / ν K → τ 0.0018 ± 0.2236 average, HFLAV 2016 τ 0.0015 ± 0.2216
HFLAV
Spring 2017
Very good prospect from Belle II, BES?
79
Emilie Passemar
P r
e s s O b s e r v a b l e T h e
y S y s . l i m i t ( D i s c
e r y ) [ a b1 ] v s L H C b / B E S I I I v s B e l l e A n
a l y N P
Br. ? ? ?
? ? ? ? ? ? ?
Br. ? ? ?
? ? ? ? ? ? ?
ACP ? ? ?
? ? ? ?? ??
? ? ? ? ? ? ?
? ? ? ? ? ? ?
g − 2 ??
?? ?? ? ? ?
g − 2 ??
? ? ? ?? ? ? ?
https://confluence.desy.de/display/BI/B2TiP+WebHome
80
precision not only the total BRs but also the energy distribution of the hadronic system huge QCD activity!
Emilie Passemar
( )
, ud us
τ
τ ν τ ν →
α S mτ
( ), Vus , ms
( ) mτ ~ 1.77GeV > ΛQCD
Γ τ − → ντ + hadronsS=0
( )
Γ τ − → ντ + hadronsS≠0
( )
81
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
ud us
d V d V s
θ =
+ = +
Davier et al’13
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
82
(αS=0)
Vus
2
Vud
2 = Rτ S
Rτ
NS
Vus
ud us
d V d V s
θ =
+ = +
Figure from
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
83
1 3.6291 0.0086
e e
B B R B
µ τ
− − − − = = = = ±
(αS≠0)
ud us
d V d V s
θ =
+ = +
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar
Rτ = Rτ
NS + Rτ S ≈ Vud 2 NC + Vus 2 NC
84
1 3.6291 0.0086
e e
B B R B
µ τ
− − − − = = = = ±
(αS≠0)
( )
2 2 ud C us C S
R V N V N
τ
α = + = + + Ο
ud us
d V d V s
θ =
+ = +
extraction of αS, |Vus|
Rτ ≡ Γ τ − → ντ + hadrons
( )
Γ τ − → ντe−ν e
( )
≈ NC
Emilie Passemar 85
(αS≠0)
Rτ
NS = Vud 2 NC + O α S
( )
measured calculated
S
α
Vus
2
Vud
2 = Rτ S
Rτ
NS + O α S
( )
ud us
d V d V s
θ =
+ = +
Cauchy Theorem
Emilie Passemar 86
Braaten, Narison, Pich’92
( ) (
)
( ) (
)
2
2 1 2 2 2 2
( ) 12 1 1 2 Im Im
m EW
ds s s R m S s i s i m m m
τ
τ τ τ τ τ τ τ τ τ
π ε π ε ε ⎡ ⎤ ⎡ ⎤ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ = − + Π + + Π + ⎢ ⎥ ⎢ ⎥ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎢ ⎥ ⎢ ⎥ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎣ ⎦ ⎣ ⎦
∫
Rτ (mτ
2) = 6iπ SEW
ds mτ
2 1 − s
mτ
2
⎛ ⎝ ⎜ ⎞ ⎠ ⎟
2
1 + 2 s mτ
2
⎛ ⎝ ⎜ ⎞ ⎠ ⎟ Π
1
( ) s
( ) + Π
( ) s
( )
⎡ ⎣ ⎢ ⎢ ⎤ ⎦ ⎥ ⎥
s =mτ
2
! ∫
( ) ( )
2 0,2,4... dim
1 ( ) ( , ) ( ) ( )
J J D D D O D
s s O s µ µ µ µ
= = = =
Π = −
∑ ∑ ∑ ∑ C
Wilson coefficients Operators
μ: separaEon scale between
short and long distances
Use of weighted distribuEons
Emilie Passemar 87
Braaten, Narison, Pich’92
( )
( )
2
1
C EW P NP
R m N S
τ τ τ τ
δ δ δ δ = + = + +
1.0201(3)
EW
S =
Marciano &Sirlin’88, Braaten & Li’90, Erler’04
2 3 4
5.20 26 127 ... 20%
P
a a a a
τ τ τ τ τ τ
δ = + = + + + + ≈
Baikov, Chetyrkin, Kühn’08
( )
s m
a
τ τ
α π =
( )
,
NS u d
R m m
τ
∝
( )
s S
R m
τ
∝
Use of weighted distribuEons Exploit shape of the spectral funcEons to obtain addiEonal experimental informaEon
Emilie Passemar 88
Le Diberder&Pich’92
( )
s S
R m
τ
∝
Rτ ≡ R00
τ
Zhang’Tau14
Emilie Passemar 89
τ-decays lattice
structure functions e+e- annihilation
hadron collider electroweak precision fjts Baikov ABM BBG JR MMHT NNPDF Davier Pich Boito SM review HPQCD (Wilson loops) HPQCD (c-c correlators) Maltmann (Wilson loops) JLQCD (Adler functions) Dissertori (3j) JADE (3j) DW (T) Abbate (T)
CMS
(tt cross section)
GFitter Hoang
(C)
JADE(j&s) OPAL(j&s) ALEPH (jets&shapes) PACS-CS (vac. pol. fctns.) ETM (ghost-gluon vertex) BBGPSV (static energy)
QCD αs(Mz) = 0.1181 ± 0.0013
pp –> jets e.w. precision fits (NNLO) 0.1 0.2 0.3
αs (Q2)
1 10 100
Q [GeV]
Heavy Quarkonia (NLO) e+e– jets & shapes (res. NNLO) DIS jets (NLO)
October 2015
τ decays (N3LO) 1000 (NLO pp –> tt (NNLO)
)
(–)
interesEng : Moderate precision at the τ mass very good precision at the Z mass
Bethke, Dissertori, Salam, PDG’15
– How to compute the perturbaEve part: CIPT vs. FOPT? – How to esEmate the non perturbaEve contribuEon? Where do we truncate the expansion, what is the role of higher order condensates? – Which weights should we use? – What about duality violaEons?
A MITP topical workshop in Mainz: March 7-12, 2016
Determinabon of the fundamental parameters of QCD A session on Tuesday axernoon
quesEons
Emilie Passemar 90