1 lhcb upgrade: flavour physics at high luminosity chris parkes eps hep conference, manchester,...
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LHCb Upgrade:Flavour Physics
at High LuminosityChris Parkes
EPS HEP Conference, Manchester, Detector Session, July 21st 2007
•LHCb - Aims for first phase (~2013)•SuperLHCb physics – Probing New Physics•Technology - Vertex Trigger, Radiation Level•Conclusion- Forward Plan
Thanks to LHCb collaborators, notably:Hans Dijkstra, Jim Libby, Franz Muheim, Guy Wilkinson,
2
p p
250 mrad
10 mrad
Dedicated B System CP Violation & Rare Decay Experiment
•Full spectrum of B hadrons:
• Bs system, All angles, sides of both CKM s
•Lots of events !
baryons ,B,B 0sd,cu,
yearper pairsbb )(10 μb, 500σ 12bb
O
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LHCb Goals - First Phase 10 fb-1
• First observation of very rare decay
• Bs mixing phase
• Unitarity Triangle
• Spectacular progress in heavy flavour physics:– Baseline measurement ACP (J/KS) – Bs Oscillations Measurement, Charm results
• Impressive range of additional measurements
Flavour Physics Progress
sB
s at 0.01 rad
BDKBsDsK B(s)h+h− exploiting U-spin
γ at few degrees
TodayToday
10 fb10 fb-1 -1
LHCbLHCb+ lattice + lattice
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LHCb Physics Programme
But NOT Limited by LHCLimited by Detector
• Upgrade to extend Physics reach – Exploit advances in detector technology
–Radiation Hard Vertex Detector–Displaced Vertex Trigger
– Better utilise LHC capabilities
• Timescale, 2015
• Collect ~100 fb-1 data
• Modest cost compared with existing accelerator infrastructure
Independent ofLHC upgrade
•SLHC not needed•But compatible
with SLHC phase
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Upgrade Physics Programme Examples
• CP Violation– Angle to better than 10
– Tree Diagram Dominated Decays, <<10 theory
– Gluonic Penguins
BdK0
KDB 0 KDB ss
Complementary to ATLAS / CMS direct searches•New particles are discovered
•LHCb measure flavour couplings through loop diagrams• No new particles are found
•LHCb probe NP at multi-TeV energy scale
KBd Angular Correlations
- Not just Afb
•Rare Decays
• Charm Physics• Mixing studies in D0→hh• CPV searches
• Rare decays, eg. D(0)(s)→l+l- [(Xu,s)]
LHCb 2 fb-1 superimposed
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Bs mixing phase s
/JBs
Upgrade can achieve 10% measurement of SM
Also measure from loops - penguin dominated
sB
= New Physics !
Standard LHCb 1 Year
SMq
iqq mehm q 21
CDF ms
Little Higgs Model
s
Blanke & Buras[hep-ph/0703117]
SM
Ligeti et al.
[hep-ph/0604112]
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Initial Phase of LHCb Operations• Data taking starts 2008
Defocus LHC beams•LHCb L= 2x1032 cm-2s-1
•Factor 50 below ATLAS/CMS design L•Most events have single interaction
•Displaced Vertex trigger•2nd level of triggering
•Multiple Interactions •Limit Triggering
rate of pp interactions
•LHCb Upgrade L= 2x1033 cm-2s-1
•Cope with 4 int./x-ing
•SLHC peak L= 8×1034 cm-2s-1
•Baseline - 40MHz, alternate High, Low I
H LLHCb
GPDs H H
Effective 20MHz Crossing rate
Select Low I for desired luminosity
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LHCb Trigger System• Cope with 4 interactions / beam crossing
Existing 1st Level Trigger 1MHz readout•Veto on multiple interactions
•Existing Trigger based on:
•High pT Muons•Calorimeter Clusters
Events with muons – trigger efficient
Events with hadrons – need improved trigger
Require Displaced Vertex TriggerAt 1st level
Current 1st Level Trigger Performance
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Trigger Gains – 40 MHz readout• Improve efficiency for hadrons and photons
– εTrig(B→hadronic) ~ 25-35%– εTrig(B→γX) ~ 30-40%– εTrig(B→μμX) ~ 60-70%
• Higher Level Trigger– Only limitations
• CPU • Algorithmic Ingenuity
– (Former) improves with Moore’s Law
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Radiation Hard Vertex Locator
• Upgrade Requires high radiation tolerance device
>1015 1 MeV neutroneq /cm2
• Strixels / Pixels– n-on-p, MCz, 3D
Z Beam
8cm
VELO Module
Active Silicon only 8mm from LHC beam
Pixel layout
x
z
390
mra
d
60 mrad
15 mrad
1 m
x
y
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LHCb Upgrade Baseline & Issues• Trigger in CPU Farm
– Event building at 40 MHZ, CPU power OK – Hadron efficiency ~ factor two improvement
• Read-out all detector 40MHz– Replace all FE Electronics
• Vertex locator, Silicon Tracker, RICH HPD, • Outer Tracker FE, Calorimeter FE boards
• Radiation Damage– Need to replace Velo anyway– Inner part of Shashlik Calorimeter– Inner part of silicon tracker– Remove muon chamber before Calorimeter
• Occupancy– Inner part of outer tracker, 6%25%
• Increase silicon coverage (faster gas, scintillating fibres)
– Tracking algorithms for higher occupancy
Inner / Outer Tracker
PWO crystals
ECAL
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• Major Physics Programme at modest cost
– Flavour Sector of New Physics s measurement
– Precision • Critical Technology
– Radiation Hard Vertex Detector
– With Displaced Vertex Trigger
• Compatible with but independent of SLHC
Upgrade Summary
W
W
b 0
sB
s
b
s 0sB
t
t? ?
?
?
LHCb preparation in good shape Looking forward to first data
And an even brighter far future
Lowry Upgrade
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University of Glasgow, Scotland1st - 5th September 2008
The conference explores the scientific and technical developments of detector systems used in: Astronomy and space
science; Astrophysics; Condensed matter studies; Industrial applications;
Life sciences; Medical physics; Nuclear Physics, Particle physics and Synchrotron based science.
National Organising
Committee(subject to change)
P.P. Allport, LiverpoolR.L. Bates, GlasgowA.J. Bird, SouthamptonC.R. Cunningham, UK
ATC, EdinburghG.E. Derbyshire, STFC,
RALP. Evans, ICR, London R. Farrow, STFC,
DaresburyW. Faruqi, MRC,
CambridgeM. Grande, AberystwythP.R. Hobson, BrunelD.P. Langstaff,
AberystwythP.J. Nolan, LiverpoolD.J. Parker, BirminghamP.J. Sellin, SurreyA. Smith, MSSL, LondonR. Speller, UCL, LondonT.J. Sumner, IC, LondonS. Watts, Manchester
psd8@physics.gla.ac.ukhttp://www.psd8.physics.gla.ac.uk
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• Extrapolating to 100 fb-1
• Only consider strategies which are theoretically clean• Critically reliant on Trigger Upgrade
Bs →DsK: statistical scaling leads to 1° uncertainty for 100 fb-1
B D(Ksππ)K: statistical scaling leads to 1.2 ° for 100 fb-1
Other modes B D(KsKπ)K, B D(KsKK)K and 4-body to be exploited
B D(hh)K: ADS/GLW methods statistics huge but will need global fit including additional information to overconstrain
Toward a sub-degree error on
LHCb
(10 fb-1)
Super-LHCb
(100 fb-1)
Super Flavour Factory
(75 ab-1)
DsK 27 k 540k -
D(Ksππ)K ≤25k 0.5M 80k
D(Kπ)fav K 280k 5.6M 131k
Extrapolationsfrom publishedB-factory analyses
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BK*μμ• AFB 0 point is not enough:
– SLHCb σs0/s0=2.1%
– Exclusive NLO theory today σs0/s0=9%
– improve by 2020• Transversity angle asymmetry
analysis extremely promising– Probes chiral structure (c.f.
TDCPV BK*γ)
– Theoretically clean– Will benefit greatly from
SLHCb statisticsLHCb 2 fb-1 superposed
Kruger and Matias, Phys.Rev.D71:094009, 2005
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Charm physicsIf charm mixing has indeed been observed, what next ?
• Precise measurements of x(‘) and y(‘)
• Search for (and detailed study) of CPV in charm – v. promising for NP
Recent detailed simulation studies at LHCb show great promise inD0→hh decays.
• After all selection cuts yield from B decays alone is expected to be 10-20 times (10 fb-1) that of total from B-factories (2 ab-1).
Target charm analyses at LHCb and SLHCb (diverse programme!):
• Mixing studies in D0→hh
• CPV search in partial width differences in D0→KK, ππ (SCS)
• CPV search in D+→K-ππ Dalitz (SCS)• Mixing and CPV in D0→Ksππ Dalitz
• Mixing and CPV in D0→K+πππ (DCS)• CPV search in T-odd moment & amplitude analysis of D0→KKππ (SCS)
• Rare decays, eg. D(0)(s)→l+l- [(Xu,s)]
Will benefit from change of trigger strategy at SLHCB
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CPV in gluonic penguin• One of the poster children of a SFF
– For good reason given the tantalising hints of a discrepancy with sin2 from bccs
• Concentrate on the cleanest modes BdK0,ηK0 and K0 K0 K0
– Average discrepancy 0.10±0.06• No attempt to add theory
– 5σ with current central value an important goal
• BdK0 most promising at current LHCb– Precision at end of LHCb 0.14
– End of SLHCb 0.03• assuming 2×εtrigger
• same as SFF but they have the other important modes…..
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Bs→ • Bs analogue of BdK0,η K0 etc
• Dependence on Vts in both the decay and Bs mixing amplitudes leads to the SM CPV being < 1% – for example M. Raidal, PRL 89,
231803 (2002) • PVV decay requires full angular
analysis to extract CP info• Simulation studies with background
and detector effects– 2000 (4000) events/fb-1 @
(S)LHCb
– NP phase sensitivity of 0.042 at current LHCb
– SLHCb sensitivity 0.009 (0.5°)
s
b
Bs0
s
s
s
s
W
t
g
1
decay
*
*
mixing
*
*
tstb
tstb
tstb
tstb
SM
VV
VV
VV
VV
A
A
p
q
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Mixing phases-the systematic frontier
• sin2 improvement can be made with control channel measurements of penguin pollution and tagging
– Bs J/ψK0S
• R. Fleischer, Eur. Phys. J. C. 10., 299 (1999)
– Push toward 1%/0.2° uncertainty
• 8% relative uncertainty on SM-like Bs mixing phase from BsJ/ψ possible at SLHCb– Matches current indirect determination– Direct proportionality to η leads to
interesting constraint on UT • // to that from KL π0νν
– Penguin control possible from BsJ/ψρ
(Super-)LHCb
2 fb-1 10 fb-1 100 fb-1
σ (stat) 0.021
0.009 0.003Superposed on LHCb 10 fb-1 + lattice
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Bs(d)μμ• 5σ observation expected at current LHCb
even if value of BF is SM• Theory prediction already at ~10% • More precise determination at SLHCb would be
constraining of NP models with large tan– c.f. BK*μμ transversity analysis constrains
small tan
• Bs μμ/Bdμμ = 32.4 ± 1.9 tightly constrained in SM and MFV– one of the magic numbers of CMFV (Buras)
• Matching theory precision is impossible with 100 fb-1
– But observation possible at SLHCb as long PID can cope with double punch-through background from Bdππ
– Maybe SLHC GPDs???? Or UltraLHCb!
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• LHCb high luminosity running L= 2x1033 cm-2s-1
• e+e- Super B-Factory– Linear Super-B (Frascati)– Super-Belle
Super B Factories
100 fb-1, 2020
50 ab-1, 2020
Complementarity•Bs – LHCb Upgrade•Neutrals – e+e-
•Bd - overlap
LHCb upgrade•Bs
•Lower cost•No new accelerator
Bs
Com
mon
No
IPN
eu
trals,
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Detector Upgrade• Critical component to achieve this physics
Radiation Hard Vertex Detector with
Displaced Vertex Trigger
VElo Superior Performance Apparatus
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•Maximum Fluence •NIEL 1 MeV neq/cm2/year•Strongly non-uniform • dependence on 1/r2 and station (z)
Middle station
Far station
Extreme Radiation Environment• LHCb VELO will
be HOT!
VESPA needs > 1015 neq/cm2 charged particle tolerance
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Radiation Hard Technologies• Active UK Technology R&D for LHC upgrades• Applicable to strixels & pixels
Extreme rad. hard
3D
Czochralski n-on-p
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Schedule & Costing• Schedule
– R&D underway• Velo/Vespa Testbeam in Autumn ’08• Exploit commonality with GPDs on Electronics
– 2010 decision on upgrade instrumentation – 2013-2015 upgrade detector during planned SLHC
upgrade – 2015-2020 gather 100 fb-1
• Cost– Front-end electronics replacement estimate 12 M€– Detailed costing not available till after R&D phase– Anticipated hardware cost ~ 45 M€
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