LHCb
LHCb Upgrade Workshop
Edinburgh, January 11–12, 2006
LHCb expected physics
–1
performance with 10 fb
Olivier Schneider
Laboratoire de Physique
des Hautes Energies (LPHE)
Olivier.Schneider@epfl.ch
LHCb
The whole idea
(unchanged since
more than a decade)
Given the fact that
— LHC will be the facility producing the largest number of b hadrons (of all types),
by far, and for a long time
— the Tevatron experiments have demonstrated the feasibility of B physics at
hadron machines
perform a dedicated B-physics experiment at the LHC,
but with a new challenge:
— exploit the huge bb production
in the not-well-known forward region,
despite the unfriendly hadronic
environment (multiplicity, …) for B physics
bb angular correlation in pp
collisions at s = 14 TeV
(Pythia)
• ~ 230 µb of bb production
in one of the forward peaks (400 mrad),
corresponding to nearly 105 b hadrons per second
at a low luminosity of 21032 cm–2s–1
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
2
LHCb
VELO: Vertex Locator (around interaction point)
TT, T1, T2, T3: Tracking stations
(before
(after
this
this
upgrade
upgrade
workshop)
workshop)
RICH1-2:
Ring
Imaging Cherenkov
detectors
ECAL, HCAL: Calorimeters
M1–M5: Muon stations
LHCb spectrometer
LHCb-1
spectrometer
1.9 < < 4.9 or
15 < < 300 mrad
Dipole
magnet
VELO
proton
beam
proton
beam
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
3
LHCb
LHCb Upgrade Workshop, Edinburgh
LHCb pit
(in December 2006)
O. Schneider, Jan 11, 2007
4
LHCb
Pileup and luminosity
LHC machine, pp collisions at s = 14 TeV:
— design luminosity = L = 1034 cm–2s–1, bunch crossing rate = 40 MHz
— average non-empty bunch crossing rate = f = 30 MHz (in LHCb)
— Pileup:
— L tuneable by adjusting final beam focusing
— Choose to run at <L> ~ 21032 cm–2s–1
(max. 51032 cm–2s–1)
• Clean environment: <n> = 0.5
• Less radiation damage
• Expected to be available from first physics run
1.0
pp interactions/crossing
0
LHCb
At LHCb:
Probability
• n = number of inelastic pp interactions occurring in the same bunch crossing
• Poisson distribution with mean <n> = Linel/f, with inel = 80 mb
• <n> = 25 at 1034 cm–2s–1 not good for B physics
n=0
0.8
0.6
0.4
1
n=1
0.2
2
3
4
— 2 fb–1 of data in 107 s (= nominal year)
31
10
32
10
33
10
Luminosity [cm−2 s−1]
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
5
LHCb
MC studies
Technical proposal (1998):
— Rough detector description
— No trigger simulation
— No pattern recognition in tracking
— Parametrized PID performance
Re-opt. Technical Design Report (2003)
— Final detector design
— Simulation of L0 and L1 trigger only
— First version of full pattern recognition
REMINDER of important
requirements for B physics
—Flexible and efficient trigger
• final states with leptons
• fully hadronic final states
—Excellent tracking:
• Track finding efficiency
• Momentum and mass resolution
• Vertexing, proper time resolution
—Particle identification (p/K//µ/e)
“DC04” MC datasets (2004–2005):
— Detailed material description
— First simulation of High-Level Trigger
“DC06” MC datasets (2006–2007):
— “Final” geometry and material description
— Redesigned High-Level Trigger
— “Final” reconstruction algorithms
Background estimates:
– based on a sample of inclusive bb
events equivalent to a few minutes
of data taking !
– sometimes can only set limits
Today’s numbers: mostly from DC04 MC, at <L> = 21032 cm–2s–1
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
6
LHCb
Expected tracking performance
High multiplicity environment:
PYTHIA+GEANT full simulation
— In a bb event, ~30 charged particles
traverse the whole spectrometer
RICH1
Track finding:
VELO
— efficiency > 95%
TT
for long tracks from B decays
(~ 4% ghosts for pT > 0.5 GeV/c)
— KS+– reconstruction 75% efficient
for decay in the VELO, lower otherwise
Magnet
T1 T2 T3
Average B-decay track resolutions:
— Impact parameter: ~30 µm
— Momentum: ~0.4%
Typical B resolutions:
— Proper time: ~40 fs (essential for Bs physics)
— Mass: 8–18 MeV/c2
RICH2
Mass resolution
Bs µµ
18 MeV/c2
Bs Ds 14 MeV/c2
Bs J/ 16 MeV/c2
Bs J/ 8 MeV/c2 *
* with J/ mass constraint
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
7
LHCb
Particle ID performance
Counts
Average efficiency:
1200
— K id = 88%
— mis-id = 3%
No PID
1000
800
600
Good K/ separation
in 2–100 GeV/c range
400
— Low momentum
200
• kaon tagging
0
5100
5150
5200
— High momentum
• clean separation
of the different
Bd,shh modes
• will be best
performance
ever achieved at
a hadron collider
Bd → π+ πBd → K+ πBs → K+ K
+
Bs → π K
Λb → p K
Λb → p π
5250
5300
5350
5400
invariant mass
5450
5500
MeV/c2
250
With PID
300
With PID
Bd → π+ πBd → K+ πBs → K+ K
Bs → π+ K
Λb → p K
Λb → p π-
250
200
Bd → π+ πBd → K+ πBs → K+ K
Bs → π+ K
Λb → p K
Λb → p π-
200
150
150
100
100
50
50
0
5.1
5.15
5.2
5.25
5.3
5.35
5.4
invariant mass
LHCb Upgrade Workshop, Edinburgh
5.45
5.5
GeV/c2
0
5.2
5.25
5.3
5.35
5.4
5.45
5.5
K invariant mass
O. Schneider, Jan 11, 2007
5.55
5.6
GeV/c2
8
LHCb
Flavour tagging
D2=(1–2w)2
Tag
Opposite µ
0.7%–1.8%
Opposite e
0.4%–0.6%
Opposite K
1.6%–2.4%
Opposite Qvtx
0.9%–1.3%
Same side (B0)
0.8%–1.0%
Same side K (Bs)
2.7%–3.3%
(B0)
4%–5%
Combined (Bs)
7%–9%
Combined
l-
Qvtx
K–
D
B0 B
s
PV
SV
K+
Performance assessed on full MC, after trigger and reconstruction
Kaon tags are the most powerful, e.g. opposite K (from bcs)
All tags combined with neural network
Tagging performance depends on how event is triggered !
— will be measured in data using control channels
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
9
LHCb
Trigger performance & rates
Algorithms and performance:
— Level-0 trigger algorithms mature, 1 MHz output rate
— High-Level Trigger (HLT) under development
• Prototype available within time budget for a limited set of channels
— L0*HLT efficiencies:
• Determined using detailed MC simulation
• Typically 30%–80% for offline-selected signal events, depending on channel
HLT output rates:
Output
Event type
rate
— Indicative rates
200 Hz
(split between streams
600 Hz
still to be determined)
— Large inclusive streams
300 Hz
to be used to control
900 Hz
calibration & systematics
(trigger, tracking, PID, tagging)
LHCb Upgrade Workshop, Edinburgh
Physics
Exclusive B candidates
High mass di-muons
B (core program)
J/, bJ/X (unbiased)
Charm
D* candidates
Inclusive b (e.g. bµ)
B (data mining)
O. Schneider, Jan 11, 2007
10
LHCb
Physics performance vs L
Rough and quick study:
— small DC04 MC samples generated at <L> = 51032 cm–2s–1
for a few representative signal channels
— backgrounds not investigated yet (but will be possible with DC06 samples)
Preliminary overall conclusion
(for L = 2–51032 cm–2s–1):
— Significant gain for dimuon channels
• yield L
— “Statu quo” for hadronic channels
• yield ~ constant
— Tagging performance seems ~constant
(at least for Bs DsK)
LHCb Upgrade Workshop, Edinburgh
same-side K
opp-side K
vertex
electron
muon
L = 21032
L = 51032
combined
O. Schneider, Jan 11, 2007
11
LHCb
Integrated luminosity scenario
2007 (end):
— Short pilot run at 450 GeV per beam with full detector installed
— Establish running procedures, time and space alignment of the detectors
— Integrated luminosity for physics ~ 0 fb–1
2008:
— LHC reaches design energy
— Complete commissioning of detector and trigger at s=14 TeV
— Calibration of momentum, energy and particle ID
— Start of first physics data taking, assume ~ 0.5 fb–1
2009–:
— Stable running, assume ~ 2 fb–1/year
Availability of physics results:
— with 0.5 fb–1 in ~2009
— with 2 fb–1 in ~2010
— with 10 fb–1 in ~2014
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
12
LHCb
Bs µ+µ–
Very rare loop decay, sensitive to new physics:
— BR ~3.510–9 in SM,
can be strongly enhanced in SUSY
— Current 90% CL limit from CDF+D0
with 1 fb–1 is ~20 times SM
Main issue is background rejection
— with limited MC statistics,
indication that main background is bµ, bµ
— assume background is dominated by bµ, bµ
LHCb expected performance:
— with 0.5 fb–1: exclude BR values down to SM value
— with 2 fb–1: 3 evidence of SM signal
— with 10 fb–1: > 5 observation of SM signal
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
13
10
Bs µ+µ–
LHCb limit on BR at 90% CL
LHCb sensitivity
(only bkg is observed)
(signal+bkg is observed)
BR (x10–9)
BR (x10–9)
LHCb
2
10
9
8
7
6
5 observation
5
Expected final CDF+D0 limit
4
SM prediction
Uncertainty in
bkg prediction
10
3
3 evidence
2
SM prediction
1
0
0.1
0.2
0.3
0.4
0.5
Integrated luminosity (fb–1)
LHCb Upgrade Workshop, Edinburgh
1
0
1
2
3
4
5
6
7
8
9
10
Integrated luminosity (fb–1)
O. Schneider, Jan 11, 2007
14
LHCb
sin(2) with B0J/KS
Expected to be one of the first CP measurements:
— Demonstrate (already with 0.5 fb–1) that we can keep under control the main
ingredients of a CP analysis
• in particular tagging extraction from control channels
— Sensitivity (from TDR, improved since):
ACP (t) =
ACP(t)
• ~ 216k signal events/2 fb–1, B/S ~ 0.8
stat(sin(2)) = 0.02
With 10 fb–1:
— Should be able to reach (sin(2)) ~ 0.010
• to be compared with 0.017
from final BaBar+Belle statistics
— Can also push further the search for
direct CP violating term cos(mdt)
N( B 0 J /KS ) N(B0 J /KS )
N( B 0 J /KS ) + N(B0 J /KS )
0.2
0
-0.2
P
-0.4
-0.6
background subtracted, 2 fb–1 (toy MC)
-0.8
0
1
2
3
4
5
6
7
8
9
10
Proper time (ps)
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
15
LHCb
BsDs+ sample and Bs mixing
— CDF observed Bs oscillations in 2006:
• ms =17.77 ± 0.10 ± 0.07 ps–1 [hep-ex/0609040]
compatible with SM
— LHCb expectation with 0.5 fb–1:
• ~35k Bs Ds+ signal events with
average t ~40 fs and Bbb/S< 0.05 at 90% CL
stat(ms) = ± 0.012 ps1, i.e. 0.07%
• will be completely dominated by
systematics on proper time scale,
but at most ((B0))/(B0) = 0.5%
Entries per 0.02 ps
Measurement of ms:
Full simulation 0.5 fb–1
(signal only, ms = 20 ps – 1)
Importance of BsDs+ sample:
Reconstructed proper time [ps – 1]
— Normalization channel for all Bs branching fraction measurements
• First absolute measurement from Belle, BR(BsDs+) = (0.68 ±0.22 ±0.16)% [hep-ex/0610003],
expect soon ~10% measurement
— Control channel for all time-dependent analyses with Bs decays
• Measurement of dilution on cos(mst) and sin(mst) terms
— Important step towards measurement of other Bs mixing parameters
• e.g. mixing phase or CP violation in mixing
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
16
LHCb
Bs mixing phase s with bccs
s is the strange counterpart of d=2:
— svery small in SM
— sSM= –arg(Vts2) =–22 = –0.036 ± 0.003 (CKMfitter)
— Could be much larger if New Physics runs in the box
Golden bccs mode is Bs J/:
— Angular analysis needed to separate
CP-even and CP-odd contributions
— Expect ~130k Bs J/(µµ) signal events/2fb–1
(before tagging), S/Bbb= 8
b
B0s s
W
t
t
W
s
0
Bs
b
Statistical sensitivities on s for 2 fb–1
Add also pure CP modes such as J/(’), c, DsDs
— No angular analysis needed, but smaller statistics
Combined sensitivity after 10 fb–1:
stat(s) = 0.010
[LHCb-2006-047]
— dominated by BsJ/
— systematics (tagging, resolution) need to be tackled
— hopefully >3 evidence of non-zero s, even if only SM
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
17
Constraints on New Physics in
Bs mixing from s measurement
LHCb
SM
New physics in Bs mixing parametrized with hs and s : M12 = (1+ h s exp(2i s )) M12
In April 2006,
including CDF’s
first measurement
of ms
>90% CL
>32% CL
>5% CL
from hep-ph/0604112
2009
2009
After LHCb
measurement
of s with
(s)= ±0.1
(~ 0.2 fb–1)
courtesy Z. Ligeti
2010
After LHCb
measurement
of s with
(s)= ±0.03
(~ 2 fb–1)
After LHCb
measurement
of s with
(s)= ±0.1
(~ 0.2 fb–1)
from hep-ph/0604112
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
18
LHCb
bsss hadronic penguin decays
Time-dependent CP analysis of penguin decays to CP eigenstates
B0 KS:
— 800 signal events per 2 fb–1, B/S < 2.4 at 90% CL
— After 10 fb–1: stat(sin(2eff)) = 0.14
— Similar to a B factory experiment
Bs :
— CP violation < 1% in SM
(Vts enters both in mixing and decay amplitudes)
significant CP-violating phase NP would be due to New Physics
— Angular analysis required
— 4k signal events per 2 fb–1 (if BR=1.410–5), 0.4 < B/S < 2.1 at 90%CL
— After 10 fb–1: stat(NP) = 0.042
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
19
LHCb
B0 K*0µ+µ
Suppressed loop decay, BR ~1.210–6
AFB(s), theory
— Forward-backward asymmetry AFB(s) in the
µµ rest-frame is sensitive probe of New Physics:
• Predicted zero of AFB(s) depends on Wilson
coefficients C7eff/C9eff
— Other sensitive observables based on transversity
angles are accessible (cf A. Golutvin)
AFB(s), fast MC, 2 fb–1
Sensitivity
s = (mµµ)2 [GeV2]
(ignoring non-resonant Kµµ evts for the time being)
s = (mµµ)2 [GeV2]
LHCb Upgrade Workshop, Edinburgh
— 7.7k signal events/2fb–1, Bbb/S = 0.4 ± 0.1
— After 10 fb–1:
zero of AFB(s) located to ±0.28 GeV2
determine C7eff/C9eff with 7% stat error (SM)
O. Schneider, Jan 11, 2007
20
LHCb
Other rare decays
B+ K+l+l– decays
— µµ/ee ratio equal to 1 in SM:
q 2max
d(B Kµµ)
R K = ds
ds
2
4 mµ
q 2max
4 m µ2
ds
d(B Kee)
= 1.000 ± 0.001
ds
Hiller & Krüger, hep-ph/0310219
— New Physics can have O(10%) effect
— After 10 fb–1: stat(RK) = 0.043
Decay
Radiative decays:
— K*:
• ACP < 1% in SM, up to 40% in SUSY
• Can measure at <% level
— :
• No mixing-induced CP asymmetry in SM,
up to 50% in SUSY
— :
• Right-handed component of
photon polarization O(10%) in SM
• Can get 3 evidence down to 15% (10 fb–1)
LHCb Upgrade Workshop, Edinburgh
2 fb–1 yield Bbb/S
B+ K+µµ
3.8k
~1
B+ K+ee
1.9k
~5
Bd K*
35k
< 0.7
Bd 40
< 3.5
Bs 9k
< 2.4
b (1115)
0.75k
< 42
b (1520)
4.2k
< 10
b (1670)
2.5k
< 18
b (1690)
2.2k
< 18
O. Schneider, Jan 11, 2007
21
LHCb
from Bs DsK
Two tree decays (bc and bu),
which interfere via Bs mixing:
— can determine s + , hence in a very clean way
— similar to 2+ extraction with B0 D*, but with the
advantage that the two decay amplitudes are similar
(~3) and that their ratio can be extracted from data
m = 14 MeV/c2
B0s { bs
s }D +
s
c
u }K –
s
Ds K
Ds π
2000
Expect 5400 signal events
in 2 fb–1
B0s { bs
s }K +
u
c
D
}
s
s
1500
1000
Bbb/S < 1 at 90% CL
Bs Ds–+ background
(with ~ 15 larger BR)
suppressed using PID:
residual contamination
only ~10%
500
(to be updated soon with DC04 MC)
0
LHCb Upgrade Workshop, Edinburgh
5.3
5.35
5.4
5.45
5.5 2
Bs mass [GeV/c ]
O. Schneider, Jan 11, 2007
22
LHCb
from Bs DsK
Fit the 4 tagged time-dependent rates:
+
−
0.25
0
−
Ds–K+: info on + ( + s)
−0.5
0.5
+
— expected to be
statistically limited
0.5
−0.25
fb–1
Asym (D s K )
() ~ 13° with 2
Both DsK asymmetries 10 fb–1, ms = 20 ps–1)
Asym (D s K )
— Extract s + , strong phase
difference , amplitude ratio
— Bs Ds also used in the fit
to constrain other parameters
(mistag rate, ms, s …)
0.25
0
−0.25
−0.5
Ds+K–: info on – ( + s)
0
0.5
1
1.5
2
2.5
3
3.5
4
t [ps]
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
23
LHCb
–
B
{ bu
from B± DK±
colour-allowed
–
s
K
}
u
c
0
D
}
u
b
B– u
colour-suppressed
u }D 0
c
s
–
K
}
u
Weak phase difference = Magnitude ratio = rB ~ 0.08
“ADS+GLW” strategy:
— Measure the relative rates of B– DK– and B+ DK+ decays with neutral D’s
observed in final states such as: K–+ and K+–, K–+–+ and K+–+–, K+K–
— These depend on:
• Relative magnitude, weak phase and strong phase between B– D0K– and B– D0K–
• Relative magnitudes (known) and strong phases between D0 K–+ and D0 K–+,
and between D0 K–+–+ and D0 K–+–+
— Can solve for all unknowns,
including the weak phase :
() = 5–15° with 2 fb–1
— Use of
B±
D* K ±
under study
LHCb Upgrade Workshop, Edinburgh
2 fb–1 yield Bbb/S
Decay
B– (K–+)D K–
28k
~0.6
B+ (K+–)D K+
28k
~0.6
B– (K+–)D K–
180
4.3
B+ (K–+)D K+
530
1.5
O. Schneider, Jan 11, 2007
24
LHCb
0
from B0 D0K*0
b
B
d
colour-suppressed
c }D 0
u
*0
s
K
}
d
0
b
B
d
colour-suppressed
u }D 0
c
*0
s
K
}
d
Weak phase difference = Magnitude ratio = rB ~ 0.4
Treat with same ADS+GLW method
— So far used only D decays to K–+, K+–, K+K– and +– final states
() = 7–10° with 2 fb–1
LHCb Upgrade Workshop, Edinburgh
Decay mode (+cc)
2 fb–1 yield Bbb/S
B0 (K+–)D K*0
3400
<0.3
B0 (K–+)D K*0
500
<1.7
B0 (K+K–, +–)D K*0
600
<1.4
O. Schneider, Jan 11, 2007
25
LHCb
Sensitivities to from BDK decays
Method
(), 2 fb–1
B mode
D mode
B+ DK+
K + KK/ + K3 ADS+GLW
B+ D*K+
K
ADS+GLW
B+ DK+
KS
Dalitz
8º
B+ DK+
KK
4-body “Dalitz”
15º
B+ DK+
K
4-body “Dalitz”
Under study
B0 DK*0
K + KK + ADS+GLW
B0 DK*0
KS
Dalitz
Bs DsK
KK
tagged, A(t)
5º–15º
Under study
Signal only,
no accept. effect
7º–10º
Under study
13º
All channels combined (educated guess):
— () = 4.2º with 2 fb–1
— () = 2.4º with 10 fb–1
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
26
LHCb
Sensitivity to SU(2) analysis of B0 +–, ±0, 00:
— Main LHCb contribution could be B0 00
Time-dependent Dalitz plot analysis of
B0 +–0 (Snyder & Quinn)
+–
–+
∆χ2
— 14k signal events/2fb–1, B/S ~1
120
2 vs Mean
RMS
250
70 expts superimposed (2fb–1)
100
average
80
7.243
2.337
Distribution
of fit error
200
15% (< 1%)
fake solutions
with 2 (10) fb–1
150
gen
60
00
100
40
50
20
0
0
0
20
40
60
80
100
120
140
160
180
0
2
4
6
8
10
12
14
16
18
20
stat() < 10º in 90% of the cases (2 fb–1)
o
α( )
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
27
LHCb
Impact of LHCb on UT
LHCb + LQCD only
10 fb–1 (2014)
η
η
2 fb–1 (2010)
LHCb (2 fb–1, 10 fb–1):
γ
1
— LHCb:
— (sin(2)) = 0.02, 0.01
— () = 4.2º, 2.4º
— () = 10º, 4.5º
γ
1
∆md
∆ms
β
0.5
∆md
∆ms
β
0.5
Lattice QCD (2010, 2014):
0
— 40, 1000 Tflop year
— ()/ = 2.5%, 1.5%
0
-0.5
-0.5
α
-1
α
Central values:
— SM assumed
(just for illustration)
-1
-1
-0.5
0
0.5
( ) / = 7.1%
( ) / = 3.9%
1
-1
ρ
-0.5
0
0.5
( ) / = 3.6%
( ) / = 1.8%
1
ρ
From V. Vagnoni, CKM workshop, Dec 2006
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
28
from B0+ and BsK+K
Penguin decays, sensitive to New Physics
Measure CP asymmetry in each mode:
ACP (t) = Adir cos(mt) + Amix sin(mt)
— Adir and Amix depend on mixing phase,
angle , and ratio of penguin to tree
amplitudes = d ei
Probability density
LHCb
— 36k B0+, B/S ~ 0.54
36k BsK+K, B/S < 0.14
— Sensitivity to Adir and Amix
~twice better than current world average
LHCb Upgrade Workshop, Edinburgh
Probability density
With 2 fb–1:
If perfect U-spin
symmetry assumed
0.01
stat() = 4°
0.005
00
Exploit U-spin symmetry (Fleischer):
— Assume d=dKK and =KK
— 4 measurements and 3 unknowns
(taking mixing phases from other modes)
can solve for 2 fb–1
0.006
50
100
150
degrees
If only
0.8<dKK/d<1.2
assumed
2 fb–1
0.004
stat() = 7–10°
+ fake solution
0.002
00
50
100
O. Schneider, Jan 11, 2007
150
degrees
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LHCb
Charm physics
Foresee dedicated D* trigger:
— Huge sample of D0h+h– decays
— Tag D0 or anti-D0 flavor with
sign of pion from D*D0
Performance studies not as
detailed as for B physics
— just started
Potentially usable statistics in 10 fb–1
D* D0(hh)
500M
D*-tagged D0K+K–
from b-hadrons
25M
D*-tagged WS D0K+–
from b-hadrons
1M
Interesting (sensitive to NP) & promising searches/measurements:
— Time-dependent D0 mixing with wrong-sign D0K+– decays
— Direct CP violation in D0K+K–
• ACP 10–3 in SM, up to 1% (~current limit) with New Physics
• Expect stat(ACP) ~ O(10–3) with 2 fb–1
— D0µ+µ–
• BR 10–12 in SM, up to 10–6 (~current limit) with New Physics
• Expect to reach down to ~510–8 with 2 fb–1
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
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LHCb
Summary
LHCb can chase New Physics in loop decays:
— couple superb highly-sensitive bs observables
s
b
b
• Bsµµ, Bs mixing phase
s
– expect interesting results with 0.5 fb–1 and 2 fb–1 already
– can measure down to SM with 10 fb–1 (in case of no New Physics)
— several other exciting windows of opportunity:
•
•
•
•
Exclusive b sss Penguin decays (limited, even with 10 fb–1)
Exclusive bsll and bs
B hh Penguins
High statistics charm physics
LHCb can improve significantly on from tree decays:
— use together with other UT observables to test CKM even more
s
b
But …
— this is only MC, performance not demonstrated in real life yet
another 2 years to go !
— while thinking about upgrade, please make sure LHCb-1 will work
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
31
LHCb
LHCb Upgrade Workshop, Edinburgh
spares
O. Schneider, Jan 11, 2007
32
LHCb
from BDK Dalitz analyses
B± D(KS+–)K±:
— D0 and anti-D0 contributions interfere in Dalitz plot
— If good online KS reconstruction: 5k signal events in 2 fb–1, B/S < 1
— Assuming signal only and flat acceptance across Dalitz plot:
() = 8° with 2 fb–1
B0 D(KS+–)K*0:
— Under study
B± D(KK)K±:
— Four-body “Dalitz” analysis
— 1.7 k signal events in 2 fb–1
— Assuming signal only and flat acceptance across Dalitz plot:
() = 15° with 2 fb–1
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
33
LHCb
Unitarity triangle in 2014
With LHCb at 10 fb–1
η
η
Without LHCb
γ
1
γ
1
0.5
εK
0
∆md
∆md
∆ms
β
0.5
V ub
V cb
εK
0
-0.5
V ub
V cb
-0.5
α
-1
∆md
∆md
∆ms
β
α
-1
-1
-0.5
0
0.5
( ) / = 4.8%
( ) / = 2.8%
1
-1
ρ
-0.5
0
0.5
( ) / = 3.5%
( ) / = 1.7%
1
ρ
From V. Vagnoni, CKM workshop, Dec 2006
LHCb Upgrade Workshop, Edinburgh
O. Schneider, Jan 11, 2007
34