Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 1/42 Vienna Central European Seminar Vienna Central European Seminar Particle Physics and the LHC Particle Physics and the LHC Jeroen van Tilburg Jeroen van Tilburg Physikalisches Institut Heidelberg Physikalisches Institut Heidelberg On behalf of the LHCb collaboration On behalf of the LHCb collaboration Status and physics at LHCb Status and physics at LHCb Outline Outline • LHCb experiment and detector LHCb experiment and detector performance performance • Selected physics results Selected physics results • Outlook and summary Outlook and summary
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Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 1/42
Vienna Central European SeminarVienna Central European SeminarParticle Physics and the LHCParticle Physics and the LHC
Jeroen van TilburgJeroen van TilburgPhysikalisches Institut HeidelbergPhysikalisches Institut Heidelberg
On behalf of the LHCb collaborationOn behalf of the LHCb collaboration
Status and physics at LHCbStatus and physics at LHCbStatus and physics at LHCbStatus and physics at LHCb
OutlineOutline• LHCb experiment and detector performanceLHCb experiment and detector performance• Selected physics resultsSelected physics results• Outlook and summaryOutlook and summary
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 2/42
New physics effects in New physics effects in BB and and DD decays decays
• New particles can appear as virtual particles in loop and penguin diagrams.• Indirect searches have a high sensitivity to effects from new particles.
• Can see NP effects before the direct searches.• Indirect measurements can access higher scales.
• Possible to measure the phases of the new couplings• New physics at TeV scale must have a flavour structure to provide suppression of FCNC.
bs
sb
b s
bs
b s
→ Complementary to direct searches.
→ Complementary to direct searches.
Strength of indirect approachStrength of indirect approachStrength of indirect approachStrength of indirect approach
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 3/42
CKM pictureCKM picture• Incredible success of CKM paradigm in last decades.• All measurements coherent with CKM of SM.
• Accuracy of angles determined by experiment• Accuracy of sides determined by theoretical uncertainties
• But, SM fails to explain matter-antimatter asymmetry in the Universe• New physics must hold additional sources of CP violation
• Effects are small but there is still room for NP effects.• Precision measurement of CKM elements.• Comparison between tree and penguin decays.• Not all CKM angles well constrained (e.g. γ and βs).
→ CP violation and rare decays of B hadronsand charm are the main focus of LHCb Large amounts of clean data available Precision tests: allow to look for small effects beyond SM
→ CP violation and rare decays of B hadronsand charm are the main focus of LHCb Large amounts of clean data available Precision tests: allow to look for small effects beyond SM
From CKMFitterFrom CKMFitterFrom CKMFitterFrom CKMFitter
015.0014.0
023.0026.0
343.0
144.0
Current fit results:
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 4/42
Tracking stationsVelo
RICH1+2
Muon
Calo
LHCb detectorLHCb detector
• Good vertex resolution• Time-dependent measurements.• Suppress background from prompt decays.
• Good particle identification • Important for trigger, flavour tagging • Suppress background.
• Good momentum resolution• Mass resolution of heavy flavours.• Suppress background.
• Good vertex resolution• Time-dependent measurements.• Suppress background from prompt decays.
• Good particle identification • Important for trigger, flavour tagging • Suppress background.
• Good momentum resolution• Mass resolution of heavy flavours.• Suppress background.
LHCb made for Heavy Flavour physicsLHCb made for Heavy Flavour physicsLHCb made for Heavy Flavour physicsLHCb made for Heavy Flavour physics
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 5/42
LHCb detectorLHCb detector
Angular coverage optimised for B-physics.
• High B hadron production at LHC • bb = 284 ± 53 b (√s = 7 TeV) [PLB 694 209]
• Forward spectrometer• Most B hadrons produced along beam axis.• Acceptance: 2 < η < 5. Complementary to GPD’s. • Vertex detector close to beam.• Easy access to planar subdetectors.
• High B hadron production at LHC • bb = 284 ± 53 b (√s = 7 TeV) [PLB 694 209]
• Forward spectrometer• Most B hadrons produced along beam axis.• Acceptance: 2 < η < 5. Complementary to GPD’s. • Vertex detector close to beam.• Easy access to planar subdetectors.
L~1 cm
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 6/42
• VELO sensors only 8 mm from beam.• Impact parameter resolution = 12 mfor high pT tracks.• Good primary and secondary vertex resolution.
• Suppress background from prompt decays.
• Good proper-time resolution• Important for time-dependent measurements.
• VELO sensors only 8 mm from beam.• Impact parameter resolution = 12 mfor high pT tracks.• Good primary and secondary vertex resolution.
• Suppress background from prompt decays.
• Good proper-time resolution• Important for time-dependent measurements.
Sensors
RF foil
Beamaxis
8 mm
[LH
Cb-C
ON
F-2011-049]
Bs J/
Prompt J/
Resolution from prompt J/ψ: t = 50 fs
…in good agreement with simulation
…in good agreement with simulation
Primary vertex resolutionPrimary vertex resolutionPrimary vertex resolutionPrimary vertex resolution Decay time in Decay time in BBs s → J/→ J/ψψ Decay time in Decay time in BBs s → J/→ J/ψψ
VELO tomography with VELO tomography with hadronic verticeshadronic vertices
VELO tomography with VELO tomography with hadronic verticeshadronic vertices
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 9/42
Flavour tagging• Tagging of production flavour (B or B)• Important for mixing & CP analyses.• Performance calibrated using control channels such as B+ → J/ψ K+
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 22/42
Direct CP in Direct CP in BBd,sd,s→K→K
B0 → K B0 → K
BBd,sd,s →→ : Clear asymmetry in raw distributions: Clear asymmetry in raw distributionsBBd,sd,s →→ : Clear asymmetry in raw distributions: Clear asymmetry in raw distributions
Bs → K Bs → K
[LH
Cb-C
ON
F-2011-042]
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 23/42
Direct CP in Direct CP in BBd,sd,s→K→K
Raw asymmetry has to be corrected for detector and production asymmetry.
AAAAAA CPCP proddetRAW
Detector asymmetry→ measured using charm control samples: D*+→D0(K)+, D*+→D0(KK)+ and D0→K.
Production asymmetry• κ: dilution of Aprod due to B mixing,
lifetime and acceptance κ(B0)~0.3, κ(Bs)~-0.03
• Aprod measured using B0→J/ K*(K)
)%2.00.1()(
)%6.07.0()(0
0
KBA
KBA
s
Interaction asymmetry
L/R detector asymmetry
)%3.10.1()( 0prod BA
Final correction factors:
[LH
Cb-C
ON
F-2011-042]
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 24/42
Direct CP in Direct CP in BBd,sd,s→K→K
008.0011.0088.0)( 0 KBACP
→ Most precise, and first 5 observation of CP violation in hadronic machine.
02.008.027.0)( KBA sCP → first 3 evidence of CP violation in Bs
0→πK
Eventual goal to measure time-dependent asymmetries in e.g. B(s) →+-, K+K-
→ determine CKM angle γ from loop decays
Compare to γ measurements from tree decays, e.g. • B+/0→D0K+/*: ADS+GLW and Dalitz method.• Bs→DsK: Time-dependent, tagged analysis.
→ determine any contribution from new physics
→ First observation of Bs→
Also measured BRs for CP eigenmodes Also measured BRs for CP eigenmodes Also measured BRs for CP eigenmodes Also measured BRs for CP eigenmodes
Preliminary[LHCb-CONF-2011-042]AACPCP for K for K modes modesAACPCP for K for K modes modes
012.0011.0098.0
WA:
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 25/42
Search for Search for BBd,s d,s ++−−
• Very rare decay (FCNC and helicity suppressed) BR(Bs +−)SM = (3.2 ± 0.2)x10−9
BR(Bd +−)SM = (1.1 ± 0.1)x10−10
• Sensitive to New Physics:• E.g. branching ratio in MSSM enhanced by sixth power of tan:
4
6
,
tan~)BR(
Asd M
B
A.J.Buras, arXiv:1012.1447
[EPJ C64 391]
Exclusion regions in MSSM (NUHM)Exclusion regions in MSSM (NUHM)
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 27/42
Search for Search for BBd,s d,s ++−−[L
HC
b-CO
NF
-2011-037]
MMfor signal region in 4 bins of BDTfor signal region in 4 bins of BDTMMfor signal region in 4 bins of BDTfor signal region in 4 bins of BDT
• Mass distribution studied in 4 bins of BDT• Expect ~ 1 event in each bin from SM.• Main background from bb→X and misidentified B→h+h−
• Mass distribution studied in 4 bins of BDT• Expect ~ 1 event in each bin from SM.• Main background from bb→X and misidentified B→h+h−
Small excess (2 events) in most sensitive bin, compatible with SM.
Expected mass resolution obtained from interpolation of dimuon resonances (from J/ to ’s)→ Verified with B → hh events
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 28/42
Search for Search for BBd,s d,s ++−−
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 29/42
0
0
0
calcal
cal
sig
calcal
0 BR)BR(q
q
q
B
B
B
q NN
N
f
fB
Search for Search for BBd,s d,s ++−−
The final branching ratio can be calculated as:NormalizationNormalization
Production ratio fs/fd taken from LHCb’s measurements using semileptonic and hadronic decays.→ Smaller error than HFAG average.→ Dominant systematic error.
LHC
b-C
ON
F-034
KB
KKJB
KJB
s
0
)()(/
)(/
Three complementary normalization channels with very different systematics:
Values for α very compatible
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 30/42
Search for Search for BBd,s d,s ++−−
• No significant excess observed in 0.3 fb-1
• Upper limits (preliminary):• BR(Bs +−) < 1.5 x 10−8 (95% CL)• BR(Bd +−) < 5.2 x 10−9 (95% CL)
• This is ~ 3.4 × SM value• Most probable value ~ 4 × 10-9
• Excess over SM not confirmed.
LHC
b-C
ON
F-2011-047
arXiv:110
8.3018
Future prospectsFuture prospects
[LHCb-CONF-2011-037]
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 31/42
• Bd +−K* rare decay in the SM.• BR (Bd l+l−K*) ~ 1.0 x 10−6
• SM diagrams can be easily modified in presence of NP• Angular distributions contain a lot of information.
• Many observables probe helicity structure of NP• Zero crossing point of AFB(q2) well predicted
in SM• Hadronic uncertainties are minimized• Measures ratio Wilson coefficients C9/C7.
• Sensitive to SUSY, graviton exchanges, extra dimensions…
Angular distributions in Angular distributions in BBd d ++−−KK**
Flipping the b→s diagram…Flipping the b→s diagram…
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 32/42
Angular distributions in Angular distributions in BBd d ++−−KK**
Results from CDF & B-factories show intriguing behaviour at low q2 :→ however, precision is limited.
SMC7=-C7
SM
[arXiv:1101.0470]
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 33/42
Angular distributions in Angular distributions in BBd d ++−−KK**
J/ veto
(2S) veto
Bd mass window
302 signal events
Event selectionEvent selection [LH
Cb-C
ON
F-2011-038]
• 309 pb-1 in 2011• 302 signal candidates• B/S ~ 0.3
Selection using BDT• BDT variables chosen to
minimize acceptance effects• Angular acceptance from MC• Trained on Bd J/ K* for signal
and mass sidebands for background
Selection using BDT• BDT variables chosen to
minimize acceptance effects• Angular acceptance from MC• Trained on Bd J/ K* for signal
and mass sidebands for background
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 34/42
Angular distributions in Angular distributions in BBd d ++−−KK**
Angular fitAngular fit
Not enough data yet to perform full angular analysis.→ Measure in 6 q2 bins:
• AFB
• Longitudinal polarisation, FL
• Differential branching fraction dГ/dq2
→ Fit AFB and FL using the 1D projections of θl and θK
Used Bd J/ K* to validate fitting procedure and angular acceptance
Used Bd J/ K* to validate fitting procedure and angular acceptance
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 35/42
Angular distributions in Angular distributions in BBd d ++−−KK**
LHCb-CONF-2011-038
In bin LHCb Theory
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 36/42
Angular distributions in Angular distributions in BBd d ++−−KK**
Next steps• Determine zero-crossing point in AFB(q2)• Add phi angle and AT
(2)
• Include full 2011 data set.• With > 2 fb-1 do full angular analysis
Next steps• Determine zero-crossing point in AFB(q2)• Add phi angle and AT
(2)
• Include full 2011 data set.• With > 2 fb-1 do full angular analysis
Data consistent with SM predictions at present sensitivity and indicate that AData consistent with SM predictions at present sensitivity and indicate that AFBFB is is
changing sign as predicted by the SMchanging sign as predicted by the SM(most recent CDF result also has negative first bin: arXiv:1108.0695)(most recent CDF result also has negative first bin: arXiv:1108.0695)
Data consistent with SM predictions at present sensitivity and indicate that AData consistent with SM predictions at present sensitivity and indicate that AFBFB is is
changing sign as predicted by the SMchanging sign as predicted by the SM(most recent CDF result also has negative first bin: arXiv:1108.0695)(most recent CDF result also has negative first bin: arXiv:1108.0695)
Already effective in constraining NP arXiv:1111.1257
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 37/42
Charm physicsCharm physics
• Dedicated trigger lines for charm decays• Yield of O(108) events per fb−1
• Flavour tag from charge of slow pion.• Large statistics available
• > 106 D0 K+K from D*+ D0 +
Many opportunities for charm physics at LHCbMany opportunities for charm physics at LHCbMany opportunities for charm physics at LHCbMany opportunities for charm physics at LHCb
[LHCb-CONF-2011-023]
D0 K+K
Mixing established in the charm sector.Mixing established in the charm sector.Next step: look for CP violationNext step: look for CP violation
Mixing established in the charm sector.Mixing established in the charm sector.Next step: look for CP violationNext step: look for CP violation
• No mixing excluded at 10.2• Presence of mixing allows to search for indirect CPV• CP violation expected to be very small in SM• Good place to look for new physics effects. HFAG averages
x=(0.63±0.19)%y=(0.75±0.12)%
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 38/42
Charm physicsCharm physics
AAГГ in in DD00→→KK++KK-- (CPV in mixing) (CPV in mixing)AAГГ in in DD00→→KK++KK-- (CPV in mixing) (CPV in mixing)
ind
00
00
)(ˆ)(ˆ)(ˆ)(ˆ
CPaKKDKKD
KKDKKDA
[LHCb-CONF-2011-046]
Measurement (2010 only; 28 pb-1):
yyCPCP in in DD00→→KK++KK-- (CPV in mixing) (CPV in mixing)yyCPCP in in DD00→→KK++KK-- (CPV in mixing) (CPV in mixing)
LHCb is currently updating with more statisticsLHCb is currently updating with more statistics
sin2
cos 1)(ˆ)(ˆ
0
0m
CP
Axy
KD
KKDy
Combined with measurement of y gives access to CPV.Measurement (2010 only; 28 pb-1):
[LHCb-CONF-2011-054]
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 39/42
Charm physicsCharm physics
ΔΔAACPCP in in DD00→→hh++hh-- (CPV in decay) (CPV in decay)ΔΔAACPCP in in DD00→→hh++hh-- (CPV in decay) (CPV in decay)
inddir 1.0)()( CPCPCPCPCP aaAKKAA
Production and detector asymmetry cancel.Measurement (2011 only; 580 pb-1):
[LHCb-CONF-2011-061]
New result!Only presented last week at HCP
Signifance 3.5
First evidence of CP violation in charm sector!
First evidence of CP violation in charm sector!
1.4 M events
0.4 M events
PreliminaryPreliminary
Preliminary
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 40/42
LHCb UpgradeLHCb Upgrade
• Main limitation that prevents exploiting higher luminosity is the Level-0 (hardware) trigger
• Proposed upgrade is to remove hardware trigger read out detector at 40 MHz (bunch crossing rate)Trigger fully in software in CPU farm.
• Will allow to increase luminosity by factor ~ 5 to 1–2 × 1033 cm-2 s-1
• Requires replacing front-end electronicsand part of tracking system. Planned for the long shutdown in 2018. Running for 10 years will then give ~ 50 fb-1
• Letter of Intent recently submitted to the LHCCPhysics case endorsed, detector R&D underway (e.g. scintillating-fibre tracking, TOF, …)
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 41/42
LHCb UpgradeLHCb Upgrade
LH
Cb
Up
gra
de
Lo
I: CE
RN
-LH
CC
-20
11
-00
1
Integrated luminosity of order 50 fbIntegrated luminosity of order 50 fb-1-1 allows to allows to measure NP effects below the % level.measure NP effects below the % level.
Integrated luminosity of order 50 fbIntegrated luminosity of order 50 fb-1-1 allows to allows to measure NP effects below the % level.measure NP effects below the % level.
Vienna Seminar, Particle physics and the LHC, 26.11.11 Status and physics at LHCb, Jeroen van Tilburg 42/42
ConclusionConclusion
No time to mention:• Bs and other radiative B decays.• Semileptonic B decays• Electroweak physics.• Higgs and exotica.• LFV tau decays• And much, much more…
No time to mention:• Bs and other radiative B decays.• Semileptonic B decays• Electroweak physics.• Higgs and exotica.• LFV tau decays• And much, much more…
• LHCb will have huge contribution to flavour physics in the years to come.
• LHCb will perform the precision measurements needed to see effects from new physics.
• The future will bring an even better understanding of our detector and much more statistics!
• Hope to see first hints from new physics soon.• Expect more interesting results this Winter.
• LHCb will have huge contribution to flavour physics in the years to come.
• LHCb will perform the precision measurements needed to see effects from new physics.
• The future will bring an even better understanding of our detector and much more statistics!
• Hope to see first hints from new physics soon.• Expect more interesting results this Winter.