Recent results and prospects of quark flavour physics at LHCb - - PowerPoint PPT Presentation
Recent results and prospects of quark flavour physics at LHCb Marco Gersabeck (The University of Manchester) Particle Physics Seminar, Birmingham, 16/11/2016 Two roads to discovery New particles = New planets ESA/Hubble 2 Direct searches
Marco Gersabeck (The University of Manchester) Particle Physics Seminar, Birmingham, 16/11/2016
2
ESA/Hubble
3
ESA/Rosetta/NAVCAM
4
David A. Aguilar (CfA)
ApJ 795 (2014) 25
0-K̅ 0 mixing and smallness of K 0→μ +μ
➡ KM mechanism predicts bottom and top quarks in 1973
0-B̅ 0 oscillations discovered in 1987
➡ Requires mtop > 50 GeV to deactivate GIM cancellation
5
0-K̅ 0 mixing and smallness of K 0→μ +μ
➡ KM mechanism predicts bottom and top quarks in 1973
0-B̅ 0 oscillations discovered in 1987
➡ Requires mtop > 50 GeV to deactivate GIM cancellation
5
d b b d B0 B0 t t W W
Then: ARGUS, 105 BB̅ decays, probing 0.1 TeV Now: LHCb, 1011 BB̅ decays, probing 100 TeV
➡ Rare processes
➡ High-precision measurements
universality
6
Small new effects can cause large relative changes Small new effects can cause large changes w.r.t. precision of prediction
7
Other experiments with significant flavour physics output: ATLAS, CDF, CMS, D0
(II)
CLEO
High-energy proton-proton collisions → General purpose flavour experiment Fixed target rare kaon decay experiments Threshold production experiments Kaon Charm/Tau Beauty
➡ Selected highlights of small and large asymmetries
➡ Rare decays
➡ Other physics areas
➡ Upgrade programmes
8
9
d0 s0 b0 = Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb d s b
VudV ⇤
ub
VcdV ⇤
cb
+ 1 + VtdV ⇤
tb
VcdV ⇤
cb
= 0
Up Charm Top Down Strange Bottom
9
d0 s0 b0 = Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb d s b
VudV ⇤
ub
VcdV ⇤
cb
+ 1 + VtdV ⇤
tb
VcdV ⇤
cb
= 0
VudV ⇤
cd
VusV ⇤
cs
+ 1 + VubV ⇤
cb
VusV ⇤
cs
= 0
VusV ⇤
ub
VcsV ⇤
cb
+ 1 + VtsV ⇤
tb
VcsV ⇤
cb
= 0
Up Charm Top Down Strange Bottom
10
Summer 2001 Summer 2011
2 8
11
Vub
B(s)→D(s)hX decays
interference of two amplitudes
➡ Combinations of B and D decays ➡ Time-integrated and time-dependent
13
VudV ⇤
ub
VcdV ⇤
cb
γ α α β sin 2
(excl. at CL > 0.95) < 0 βα β γ
ρ
η
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 excluded area has CL > 0.95 Summer 14CKM
f i t t e rCP violation in B-→D(K+π-π0)π-
(0,-)→Dh (h=π,K,K *) decays
➡ Observables are time-integrated ratios of rates and rate asymmetries
➡ Measure favoured B decay with doubly Cabibbo-suppressed D decay and vice versa
➡ Measure favoured/suppressed B decays with D decaying into CP eigenstate
➡ Measure favoured/suppressed B decays with D decaying into multi-body final state including Dalitz analysis
➡ Need to perform time-dependent measurement of rates and asymmetries
14
] ° [ γ 1-CL
0.2 0.4 0.6 0.8 1 50 60 70 80 90 68.3% 95.5%
LHCb
(*) decays
*:
➡ (70±18)°
*:
➡ (73±14)°
➡ SM measurements ➡ Access to beyond SM particles through loops in γ measurements using B→hh(h) decays
15
arXiv:1611.03076
*CKMFitter Summer 2014
(72±7)°
➡ Forbidden directly, requires B̅→B oscillation
➡ CP violation in mixing
➡ Separate access to Asl(Bd) & Asl(BS)
➡ Measures combination of Asl(Bd) & Asl(BS)
16
b c q q l+ ν Bq W
flavour-specific
SM by about 3σ ➡ Difficult to motivate by non-SM physics
show agreement with SM
to observables?
asl(Bd) and asl(Bs) ➡ Latest: asl(Bs)=(0.39±0.26±0.20)% PRL 117 (2016) 061803
17
[%]
d sl
a
3 − 2 − 1 − 1
[%]
s sl
a
4 − 3 − 2 − 1 − 1 Standard Model
X ν µ
(*)
D LHCb X ν µ
(*)
D D0 ν l
*
D BaBar ll BaBar ll Belle µ µ D X ν µ
s
D D0 X ν µ
s
D LHCb
VudV ⇤
cd
VusV ⇤
cs
+ 1 + VubV ⇤
cb
VusV ⇤
cs
= 0
weakly decaying hadrons ➡ Unique physics access
➡ Huge cancellations ➡ Theoretically difficult
➡ Predictions even smaller
➡ Blessing and a curse
19
Need 1000 lifetimes to see a full D0-D̅0 oscillation → Not enough charm in the universe!
D0-D̅0 mixing
1000 TeV
Probing highest scales
→ Isidori, Nir, Perez, ARNPS 60 (2010) 355
t [ps] 1 2 3 (t)
CP
A 0.02 − 0.01 − 0.01 Data Fit Prompt signal LHCb Preliminary LHCb Preliminary Pull 5 − 5
−0.04 −0.02 0.00 0.02 0.04
AKK
corr (t)
LHCb preliminary
2011 Up 2011 Down
2 4 6 8 −0.04 −0.02 0.00 0.02 0.04
AKK
corr (t)
LHCb preliminary
2012 Up 2012 Down
20
t/τD
0→K
+ and D 0→π
+ decays
➡ AГ ≈ am y cosϕ + x sinϕ ≡ -aCP
ind
*+-tagged, 3 fb
➡ AГ(KK) = (-0.30±0.32±0.14)×10
+-tagged, 3 fb
➡ AГ(KK) = (-1.34±0.77±0.30)×10
20
Binned Unbinned
LHCb-CONF-2016-009 LHCb-CONF-2016-010
21
EPJC 73 (2013) 2373
*after A. Lenz @ CHARM 2013, arXiv:1311.6447
22
PRL 116 (2016) 191601 JHEP 07 (2014) 014
23
23
23
23
23
23
23
23
)[%]
+
π
−
π (
CP
A 0.5 − 0.5 )[%]
+
K
−
K (
CP
A 0.5 − 0.5
LHCb
semileptonicLHCb
promptLHCb
combLHCb HFAG
charm CP violation ➡ Approaching 10
hypothesis at 9% level
24
Mixing-related CP violation CP violation in decay
− +
➡ Computationally challenging for O(1M) events ➡ Use GPUs to exploit massive parallelisation ➡ Applied to D0→π+π−π0 decays
➡ Test statistic (T) comparing pairwise weighted distances in phase space ➡ Compare D0↔D0 D̅0↔D̅0 D0↔D̅0 ➡ Expect T~0 (no CPV) or T>0 (CPV)
25 PLB 740 (2015) 158
− +
➡ Computationally challenging for O(1M) events ➡ Use GPUs to exploit massive parallelisation ➡ Applied to D0→π+π−π0 decays
➡ Test statistic (T) comparing pairwise weighted distances in phase space ➡ Compare D0↔D0 D̅0↔D̅0 D0↔D̅0 ➡ Expect T~0 (no CPV) or T>0 (CPV)
25 PLB 740 (2015) 158
⬅
− +
➡ Computationally challenging for O(1M) events ➡ Use GPUs to exploit massive parallelisation ➡ Applied to D0→π+π−π0 decays
➡ Test statistic (T) comparing pairwise weighted distances in phase space ➡ Compare D0↔D0 D̅0↔D̅0 D0↔D̅0 ➡ Expect T~0 (no CPV) or T>0 (CPV)
25 PLB 740 (2015) 158
⬅
− +
➡ Computationally challenging for O(1M) events ➡ Use GPUs to exploit massive parallelisation ➡ Applied to D0→π+π−π0 decays
➡ Test statistic (T) comparing pairwise weighted distances in phase space ➡ Compare D0↔D0 D̅0↔D̅0 D0↔D̅0 ➡ Expect T~0 (no CPV) or T>0 (CPV)
25 PLB 740 (2015) 158
⬅
➡ 5-dimensional phase-space ➡ Split D0 and D̅0 (P-even) ➡ And by sign of decay planes (P-odd)
compatible with no- CPV hypothesis
26 LHCb-PAPER-2016-044
Preliminary Preliminary
p-value (4.6±0.5)% p-value (0.6±0.2)% No-CPV hypothesis from permutations with randomised flavour tags
➡ in bins of phase space ➡ in bins of decay-plane angle
uncertainties
from no-CPV hypothesis
Λb→pπ−K+K− sample
28
Φ
π+
π−
slowπ−
fastp Λ0
b { b
d u u d u d u u d (s) u d (s) Vub V ∗
ud
W −
}
p
}π+ (K+) }π− (K−) }π−
Λ0
b{
t W − b d u d u u d u u d (s) u d (s) Vtb V ∗
td
}
p
}π+ (K+) }π− (K−) }π−
Asymmetries [%]
Phase space bin
5 10
20 20 −
/ndf=21.1/12
2
χ
CP
T
a
20 20 −
LHCb Scheme A
/ndf=27.9/12
2
χ
P
T
a
Asymmetries [%]
| [rad] Φ |
1 2 3
20 20 −
/ndf=30.5/10
2
χ
CP
T
a
20 20 −
LHCb Scheme B
/ndf=20.7/10
2
χ
P
T
a
arXiv:1609.05216
D(s)
±→π ±π +π − decays
η’ and comparable to best limit on η
including reconstruction at trigger level for 2015 data
29
]
10 × ) [
−
π
+
π → ' η B( 2 4 6
s
CL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
sObserved CL
Expected CL σ 1 ±
sExpected CL σ 2 ±
sExpected CL
LHCb ]
10 × ) [
−
π
+
π → η B( 2 4 6
s
CL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
sObserved CL
Expected CL σ 1 ±
sExpected CL σ 2 ±
sExpected CL
LHCb
arXiv:1610.03666
Needles in the haystack Precision needle stack physics
whoabang.tumblr.com
]
2
c ) [MeV/
−
µ
+
µ
−
π
+
K ( m
5200 5400 5600
2
c Candidates / 11 MeV/
200 400 600
LHCb
−
µ
+
µ
*0
K → B
➡ Particular sensitivity to electromagnetic penguins
➡ Forward-backward asymmetry of muons, AFB ➡ Longitudinal polarisation fraction of K
*
, FL ∝ cos
2
θK ➡ Further angular observables, Si (i=3,4,5,6) ➡ Derived observables with reduced form-factor dependence, Pi’ = Si/√FL(1-FL)
31 JHEP 02 (2016) 104
Full run-1 data: ~2400 candidates
32
]
4
c /
2
[GeV
2
q
5 10 15 20
'
5
P
0.2 0.4 0.6 0.8 1
SM Predictions Data
LHCb PRL 111 (2013) 191801
32
]
4
c /
2
[GeV
2
q
5 10 15 20
'
5
P
0.2 0.4 0.6 0.8 1
SM Predictions Data
LHCb PRL 111 (2013) 191801
]
4
c /
2
[GeV
2
q
5 10 15
5
' P
1 2
LHCb
SM from DHMV
JHEP 02 (2016) 104
SM prediction from Descotes-Genon, Hofer, Matias, Virto, JHEP 1412 (2014) 125
have done so far are nicely fulfilled with 3 fb-1 showing robustness of data.” (Matias @ Moriond EW 2015)
charm effect mimicking C9
NP < 0 at intermediate q2
could solve the tensions as well.” (Straub @ Moriond EW 2015)
33
Z’ still possible within indirect and direct constraints * Many more LHCb results adding to the picture!
Straub, LHCb Implications 2016 Descotes-Genon et al., JHEP 06 (2016) 092
have done so far are nicely fulfilled with 3 fb-1 showing robustness of data.” (Matias @ Moriond EW 2015)
charm effect mimicking C9
NP < 0 at intermediate q2
could solve the tensions as well.” (Straub @ Moriond EW 2015)
33
Z’ still possible within indirect and direct constraints * Many more LHCb results adding to the picture!
Straub, LHCb Implications 2016 Descotes-Genon et al., JHEP 06 (2016) 092
]
4
c /
2
[GeV
2
q
5 10 15 20
K
R
0.5 1 1.5 2 SM
LHCb LHCb
LHCb BaBar Belle
Lepton universality violated?
➡ Precise SM predictions and high sensitivity to BSM physics
+μ
+μ
lifetime, … ➡ Need much more data
34
→ B0
s
W + W − Z0 t b s µ+ µ− →
s
W + ν W − t b s µ− µ+ →
s
X+ W − X0 t b s µ+ µ− →
s
X+ ν W − t b s µ+ µ−
]
2c [MeV/
− µ + µm
5000 5200 5400 5600 5800
)
2c S/(S+B) weighted cand. / (40 MeV/
10 20 30 40 50 60 Data Signal and background
−µ
+µ →
sB
−µ
+µ → B Combinatorial bkg. Semileptonic bkg. Peaking bkg.
CMS and LHCb (LHC run I)
CMS and LHCb, Nature 522 (2015) 68
35
)
+
τ →
s
B(B
0.001 0.002 0.003 0.004 0.005 0.006 0.007
p-value
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 LHCb Preliminary
LHCb-CONF-2016-011
at 90% CL
2011+12 data
previous 40-year old limit ➡ 5.8×10-9 at 90% CL
programme of strange physics at LHCb
36
9
10 × )
+
µ →
S
B(K
5 10 15
CL
0.8 0.85 0.9 0.95 1
LHCb Preliminary
LHCb-CONF-2016-012
)
2
(MeV/c
µ
m
500 550 600
)
2
Events / ( 1.3 MeV/c
1 10
210
LHCb Preliminary
500 550 600 5 − 5KS→π+π− double mis-ID
Other physics areas
…
38
Central exclusive production Electroweak physics Heavy ion collisions Production & Spectroscopy Exotica X(4140) X(3872) Forward shower counters J/ψ, X(3872), Υ production Hadron decays to Spin-3 state Ridge analysis Production in p-Pb collisions Associated W/Z production Forward energy flow → link to all >340 LHCb papers Ξb’-, Ξb*- Z(4430)- Improving HERA PDF measurements Forbidden decays Lepton-flavour violation τ decays Top production
]
2
[GeV
Kp 2
m
2 3 4 5 6
]
2
[GeV
p ψ J/ 2
m
16 18 20 22 24 26
LHCb
[GeV]
p ψ / Jm
4 4.2 4.4 4.6 4.8 5Events/(15 MeV)
100 200 300 400 500 600 700 800LHCb
(b)
=205 MeV =102 MeV
*,
=205 MeV,
*, Λ
20 40 60 80 100120140160180 1 10
2
10
3
10
) ) | H L (-2ln ∆ (
t
F
data
LHCb
discovered in 2015 ➡ Model-independent confirmation in 2016
➡ First full amplitude analysis ➡ Three new states plus one known suspect
39
PRL 117 (2016) 082002
[MeV]
φ ψ J/m
4100 4200 4300 4400 4500 4600 4700 4800 Candidates/(10 MeV) 20 40 60 80 100 120
LHCb
arXiv:1606.07895
NEW DsDs* cusp?
7 TeV and 13 TeV
PDF at low x
atmospheric neutrino background prediction at very high energies
40
500 1000 1500 2000
σ(pp → c¯ cX) [µb]
POWHEG+NNPDF3.0L FONLL LHCb average LHCb D+ LHCb D0 0 < pT < 8 GeV/c, 2 < y < 4.5
LHCb √s = 5 TeV
arXiv:1610.02230 Gauld, Rojo, arXiv:1610.09373
➡ 2 BDTs, secondary vertex detection, corrected mass
41 JINST 10 P06013
) b +b
σ ) b +b
+(W σ
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18
[pb] σ ) c +c
σ ) c +c
+(W σ
0.1 0.2 0.3 0.4
[pb] σ ) t (t σ
0.02 0.04 0.06 0.08 0.1
[pb] σ
MCFM CT10
statData
totData
= 8 TeV s LHCb,
[GeV]
jjm
50 100 150 200Events / ( 20 GeV )
5 10 15 20 25 30 35LHCb
= 8 TeV s a) uGB
0.2 0.4 0.6Events / ( 0.05 )
2 4 6 8 10 12 14 16 18 20LHCb
= 8 TeV s b) BDT(b|c)
1j
1 − 0.5 − 0.5 1Events / ( 0.2 )
2 4 6 8 10 12 14 16 18 20 22LHCb
= 8 TeV s c) BDT(b|c)
2j
1 − 0.5 − 0.5 1Events / ( 0.2 )
2 4 6 8 10 12 14 16 18 20 22LHCb
= 8 TeV s d)
)
+
µ Data( b W+b t t c W+c Background
arXiv:1610.08142
➡ One day maybe
cc̅ ➡ bb̅ has potential with LHCb upgrade ➡ cc̅ in SM will be challenging
non-SM rates
42
SM)] b b → (H B ) W/Z + H → (pp σ [ ) b b → (H B ) W/Z + H → (pp σ
50 100
s
CL
0.2 0.4 0.6 0.8 1
= 8 TeV s LHCb preliminary expected σ 1- σ 2-5000
s
CL
0.2 0.4 0.6 0.8 1
= 8 TeV s LHCb preliminary expected σ 1- σ 2-LHCb-CONF-2016-006
Upgrading flavour experiments
➡ MEG, mu3e, mu2e, COMET, g-2, …
44 BESIII NA62 Belle II
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2014 2013 2012 2011 2026
LHC run-1 LHC run-3 LHC run-2 LHC run-4 LHCb LHCb Phase-I upgrade ATLAS & CMS upgrades ATLAS & CMS
Nov 2016
➡ Limited by hardware trigger
➡ Requires several new detectors (all tracking plus RICH) and new readout electronics otherwise
➡ Massively improved trigger efficiencies ➡ Offline quality reconstruction in trigger
➡ Vertex Locator and RICH built in UK
45
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024-26 2027 2014 2013 2012 2011
LHC run-1 LHC run-3 LHC run-2 LHC run-4 LHCb LHCb Phase-I upgrade
Nov 2016 today
Belle 2
46
➡ Several hints demand more precise and complementary measurements as well as advances on the theoretical side
➡ Stay tuned for latest updates at CKM
➡ Belle II, BESIII, COMET, g-2, LHCb run-2, LHCb upgrade(s), MEG, mu2e, mu3e, NA62
46
➡ Several hints demand more precise and complementary measurements as well as advances on the theoretical side
➡ Stay tuned for latest updates at CKM
➡ Belle II, BESIII, COMET, g-2, LHCb run-2, LHCb upgrade(s), MEG, mu2e, mu3e, NA62