![Page 1: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/1.jpg)
Olivier Schneider
LHCb Upgrade WorkshopEdinburgh, January 11–12, 2006
LHCb expected physics performance with 10 fb–1
Laboratoire de Physique des Hautes Energies (LPHE)
![Page 2: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/2.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 2
The whole idea 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
• ~ 230 b of bb production in one of the forward peaks (400 mrad),corresponding to nearly 105 b hadrons per secondat a low luminosity of 21032 cm–2s–1
bb angular correlation in pp collisions at s = 14 TeV
(Pythia)
(unchanged since more than a decade)
![Page 3: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/3.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 3
LHCb spectrometer (before this upgrade workshop)LHCb-1 spectrometer (after this upgrade workshop)
VELO
VELO: Vertex Locator (around interaction point) TT, T1, T2, T3: Tracking stations RICH1-2: Ring Imaging Cherenkov detectorsECAL, HCAL: CalorimetersM1–M5: Muon stations
proton beam
proton beam
Dipolemagnet
1.9 < < 4.9 or 15 < < 300 mrad
![Page 4: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/4.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 4
LHCb pit (in December 2006)
![Page 5: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/5.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 5
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:
• 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
At LHCb:—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
—2 fb–1 of data in 107 s (= nominal year)
pp interactions/crossing
LH
Cb
n=0
n=1
![Page 6: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/6.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 6
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
“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
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///e)
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
![Page 7: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/7.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 7
VELO
TT
T1 T2 T3 RICH2
RICH1
Magnet
PYTHIA+GEANT full simulation
Expected tracking performance High multiplicity environment:
— In a bb event, ~30 charged particles traverse the whole spectrometer
Track finding:— efficiency > 95%
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
Average B-decay track resolutions:— Impact parameter: ~30 m — Momentum: ~0.4%
Typical B resolutions:— Proper time: ~40 fs (essential for Bs physics)— Mass: 8–18 MeV/c2
Mass resolution
Bs 18 MeV/c2
Bs Ds 14 MeV/c2
Bs J/ 16 MeV/c2
Bs J/ 8 MeV/c2
* with J/ mass constraint
*
![Page 8: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/8.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 8
Particle ID performance Average efficiency:
—K id = 88% mis-id = 3%
Good K/ separation in 2–100 GeV/c range—Low momentum
• kaon tagging —High momentum
• clean separation of the different Bd,shh modes
• will be best performance ever achieved at a hadron collider
invariant mass K invariant mass
With PID With PID
invariant mass
No PID
![Page 9: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/9.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 9
Flavour tagging
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
Tag D2=(1–2w)2
Opposite 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%
Combined (B0) 4%–5%
Combined (Bs) 7%–9%
Qvtx
BsB0
D
l-K–
K+PVSV
![Page 10: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/10.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 10
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:—Indicative rates
(split between streams still to be determined)
—Large inclusive streams to be used to control calibration & systematics (trigger, tracking, PID, tagging)
Output rate
Event type Physics
200 Hz Exclusive B candidates
B (core program)
600 Hz High mass di-muons J/, bJ/X (unbiased)
300 Hz D* candidates Charm
900 Hz Inclusive b (e.g. b) B (data mining)
![Page 11: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/11.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 11
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)
same-side Kopp-side K
vertexelectron
muoncombined
L = 21032
L = 51032
![Page 12: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/12.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 12
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
![Page 13: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/13.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 13
Bs +–
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 b, b
—assume background is dominated by b, b 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
![Page 14: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/14.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 14
Bs +–
LHCb limit on BR at 90% CL (only bkg is observed)
LHCb sensitivity(signal+bkg is observed)
Integrated luminosity (fb–1)
5 observation
3 evidence
SM prediction
BR
(x1
0–9)
Integrated luminosity (fb–1)
BR
(x1
0–9)
Uncertainty in bkg prediction
Expected final CDF+D0 limit
SM prediction
![Page 15: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/15.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 15
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):
• ~ 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)
AC
P(t
)
€
ACP(t) =N B 0 → J /ψKS( ) − N B0 → J /ψKS( )
N B 0 → J /ψKS( ) + N B0 → J /ψKS( )
background subtracted, 2 fb–1 (toy MC)
![Page 16: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/16.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 16
BsDs+ sample and Bs mixing
Measurement of ms:— 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%
Importance of BsDs+ sample:
— 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
Reconstructed proper time [ps – 1]
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.Ent
ries
per
0.0
2 ps
Full simulation 0.5 fb–1 (signal only, ms = 20 ps – 1)
![Page 17: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/17.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 17
Bs mixing phase s with bccs s is the strange counterpart of d=2:
s very small in SM s
SM = –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/() signal events/2fb–1
(before tagging), S/Bbb= 8
Add also pure CP modes such as J/(’), c, DsDs — No angular analysis needed, but smaller statistics
Combined sensitivity after 10 fb–1:
— dominated by BsJ/— systematics (tagging, resolution) need to be tackled— hopefully >3 evidence of non-zero s, even if only SM
€
W
€
W
€
b
€
Bs0
⎧ ⎨ ⎪
⎩ ⎪
€
s
€
b€
s
€
⎫ ⎬ ⎪
⎭ ⎪ B s
0
€
t
€
t
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
Statistical sensitivities on s for 2 fb–1
stat(s) = 0.010 [LHCb-2006-047]
![Page 18: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/18.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 18
Constraints on New Physics in Bs mixing from s measurement
In April 2006, including CDF’s first measurement
of ms >90% CL
>32% CL>5% CL from hep-ph/0604112
After LHCb measurement of s with (s)= ±0.1(~ 0.2 fb–1)
After LHCb measurement of s with (s)= ±0.1(~ 0.2 fb–1)
After LHCb measurement of s with (s)= ±0.03(~ 2 fb–1)
€
New physics in Bs mixing parametrized with hs and σ s : M12 = 1+ hs exp(2iσ s)( ) M12SM
from hep-ph/0604112
courtesy Z. Ligeti
2009
2009
2010
![Page 19: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/19.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 19
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
![Page 20: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/20.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 20
B0 K*0
s = (m)2 [GeV2]
AFB(s), theory
Sensitivity (ignoring non-resonant K evts for the time being)
—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 C7
eff/C9eff with 7% stat error (SM)
Suppressed loop decay, BR ~1.210–6
—Forward-backward asymmetry AFB(s) in the rest-frame is sensitive probe of New Physics:• Predicted zero of AFB(s) depends on Wilson
coefficients C7eff/C9
eff
—Other sensitive observables based on transversity angles are accessible (cf A. Golutvin)
AFB(s), fast MC, 2 fb–1
s = (m)2 [GeV2]
![Page 21: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/21.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 21
Other rare decays B+ K+l+l– decays
/ee ratio equal to 1 in SM:
—New Physics can have O(10%) effect—After 10 fb–1: stat(RK) = 0.043
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)
Hiller & Krüger, hep-ph/0310219
€
RK = dsdΓ(B → Kμμ)
ds4 mμ
2
q max2
∫ dsdΓ(B → Kee)ds
4 mμ2
q max2
∫ =1.000 ± 0.001
Decay 2 fb–1 yield Bbb/S
B+ K+ 3.8k ~1
B+ K+ee 1.9k ~5
Bd K* 35k < 0.7
Bd 40 < 3.5
Bs 9k < 2.4
b 0.75k < 42
b 4.2k < 10
b 2.5k < 18
b 2.2k < 18
![Page 22: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/22.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 22
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
from Bs DsK
Bs Ds–+ background
(with ~ 15 larger BR)suppressed using PID: residual contamination
only ~ 10%
Expect 5400 signal events in 2 fb–1
Bbb/S < 1 at 90% CL
(to be updated soon with DC04 MC)
m = 14 MeV/c2
€
s
€
s
€
b
€
c
€
u
€
s
€
Bs0{
€
}Ds−
€
}K+
€
}K–
€
s
€
s
€
b
€
u
€
c
€
s
€
Bs0{
€
}Ds+
![Page 23: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/23.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 23
Fit the 4 tagged time-dependent rates:—Extract s + , strong phase
difference , amplitude ratio—Bs Ds also used in the fit
to constrain other parameters (mistag rate, ms, s …)
() ~ 13 with 2 fb–1 —expected to be
statistically limited
from Bs DsK
Both DsK asymmetries 10 fb–1, ms = 20 ps–1)
Ds–K+: info on + ( + s)
Ds+K–: info on – ( + s)
![Page 24: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/24.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 24
from B± DK±
“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 :
—Use of B± D*K± under study
€
u
€
b
€
u
€
s
€
c
€
u
€
B– ⎧ ⎨ ⎩
€
}D 0
€
}K–
colour-suppressed
€
u
€
u
€
b
€
c
€
u
€
s
€
B–{
€
}D0
€
}K–
colour-allowed
Weak phase difference = Magnitude ratio = rB ~ 0.08
Decay 2 fb–1 yield Bbb/S
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
() = 5–15 with 2 fb–1
![Page 25: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/25.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 25
Treat with same ADS+GLW method—So far used only D decays to K–+, K+–, K+K– and +– final states
from B0 D0K*0
€
}D0
€
d
€
b
€
d
€
s
€
c
€
u
€
B0 ⎧ ⎨ ⎩
€
}K*0
colour-suppressed
Weak phase difference = Magnitude ratio = rB ~ 0.4
€
d
€
b
€
d
€
s
€
u
€
c
€
B0 ⎧ ⎨ ⎩
€
}D 0
€
}K*0
colour-suppressed
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
() = 7–10 with 2 fb–1
![Page 26: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/26.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 26
Sensitivities to from BDK decays
All channels combined (educated guess): () = 4.2º with 2 fb–1
() = 2.4º with 10 fb–1
B mode D mode Method (), 2 fb–1
B+ DK+ K + KK/ + K3 ADS+GLW 5º–15º
B+ D*K+ K ADS+GLW Under study
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 7º–10º
B0 DK*0 KS Dalitz Under study
Bs DsK KK tagged, A(t) 13º
Signal only, no accept. effect
![Page 27: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/27.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 27
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)
—14k signal events/2fb–1, B/S ~1
00
–+
+–
average
gen
70 expts superimposed (2fb–1)
2 vs Distribution of fit error
stat() < 10º in 90% of the cases (2 fb–1)
15% (< 1%) fake solutions with 2 (10) fb–1
![Page 28: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/28.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 28
Impact of LHCb on UT
LHCb (2 fb–1, 10 fb–1):— LHCb: (sin(2)) = 0.02, 0.01 () = 4.2º, 2.4º () = 10º, 4.5º
Lattice QCD (2010, 2014):— 40, 1000 Tflop year ()/ = 2.5%, 1.5%
Central values:— SM assumed
(just for illustration)
%8.1/)(
%6.3/)(
==
10 fb–1 (2014)2 fb–1 (2010)
%9.3/)(
%1.7/)(
==
LHCb + LQCD only
From V. Vagnoni, CKM workshop, Dec 2006
![Page 29: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/29.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 29
from B and BsKK
Penguin decays, sensitive to New Physics Measure CP asymmetry in each mode:
—Adir and Amix depend on mixing phase, angle , and ratio of penguin to tree amplitudes = d ei
Exploit U-spin symmetry (Fleischer):—Assume d=dKK and =KK —4 measurements and 3 unknowns
(taking mixing phases from other modes) can solve for
With 2 fb–1:—36k B, B/S ~ 0.54
36k BsKK, B/S < 0.14—Sensitivity to Adir and Amix
~ twice better than current world average
€
ACP(t) = Adir cos(Δmt) + Amix sin(Δmt) stat() = 4
If perfect U-spin symmetry assumed
stat() = 7–10 + fake solution
If only 0.8<dKK/d<1.2
assumed
2 fb–1
2 fb–1
![Page 30: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/30.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 30
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
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
— D0+–
• 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
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
![Page 31: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/31.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 31
Summary LHCb can chase New Physics in loop decays:
—couple superb highly-sensitive bs observables• Bs, Bs mixing phase
– 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
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
bs
sb
b s
![Page 32: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/32.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 32
spares
![Page 33: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/33.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 33
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
![Page 34: Olivier Schneider LHCb Upgrade Workshop Edinburgh, January 11–12, 2006 LHCb expected physics performance with 10 fb –1 Olivier.Schneider@epfl.ch Laboratoire](https://reader038.vdocument.in/reader038/viewer/2022103122/56649cff5503460f949d075d/html5/thumbnails/34.jpg)
O. Schneider, Jan 11, 2007LHCb Upgrade Workshop, Edinburgh 34
Unitarity triangle in 2014
%7.1/)(
%5.3/)(
==
%8.2/)(
%8.4/)(
==
Without LHCb With LHCb at 10 fb–1
From V. Vagnoni, CKM workshop, Dec 2006