Transcript Future experiments at existing machines

QCDWorkshop
Martina Franca, June 16–19, 2007
B physics in the LHC
program
Does flavor physics in the LHC era
increase our understanding?
Clara Matteuzzi
INFN and
Universita Milano-Bicocca
Clara Matteuzzi
QCD 2007 Martina Franca
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Contents
1. Present status of the CKM
2. The start up of LHC
3.
Experiments at LHC: potential
(some examples)
4. B physics beyond 2009
Clara Matteuzzi
QCD 2007 Martina Franca
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Where is Flavour Physics now ??
• The PEP-II/BABAR and KEKB/Belle B Factories,
together with CLEO-c and recent K decay
experiments, have reached the precision measurement
regime for many parameters
• CDF and DØ at Tevatron Run II are now producing
beautiful results on Bs mixing, rare decays and
b baryon studies
Clara Matteuzzi
QCD 2007 Martina Franca
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Current status of CKM parameters
= 0.2258±0.0011
A = 0.83±0.02
 = 0.168±0.029
 = 0.340±0.017
With 2 ab-1
δ(ρ,η) = (10%,4.4%)
Accuracy of angles is
limited by experiment:
α ~ ± 12°
β ~ ± 1°
γ ~ ± (20°-30°)
χ not yet measured
Accuracy of sides is
limited by theoretical
uncertainty
Clara Matteuzzi
QCD 2007 Martina Franca
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Current status of CKM parameters
All measurements related with electroweak quark transitions are
coherent with the CKM picture of the Standard Model
Overconstrained tests of the CKM matrix to the level of precision
warrented by theoretical uncertainties (will theory be able to calculate
hadronic parameters with 1% precision in 10 years?)
The CKM phase is consistent with being the source for all observed
CP-violating phenomena
There must, however, be additional sources of CP violation
Goal of heavy flavour physics is now shifting from
understanding of CKM in the Standard Model (SM)
to
search for physics Beyond the Standard Model (BSM)
appearing in loops.
Clara Matteuzzi
QCD 2007 Martina Franca
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The LHC era begins ……..
LHCb
ATLAS/LHCf
CMS/TOTEM
ALICE
Clara Matteuzzi
QCD 2007 Martina Franca
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The LHC experiments
LHC starts at √s = 14 TeV middle of 2008
ALICE
heavy ion and pp experiment
ATLAS
general purpose pp experiment
CMS
general purpose pp experiment
LHCb
dedicated Heavy Flavour experiment
Middle of 2008:
Start of run @ s = 14 TeV
calibration and trigger commissioning,
increasing luminosity toward 1033 for ATLAS/CMS
and ~21032 for LHCb for physics
From 2009:
Stable physics run @ s = 14 TeV
ATLAS and CMS: clear interest to increase
luminosities towards 1034 as quick as possible.
B physics will become increasingly difficult.
LHCb: collecting data with <1033 for some years
Clara Matteuzzi
QCD 2007 Martina Franca
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The
flavour
stage
The stage
………..
2008
physics run for a period of 1/4 of the nominal year (107 sec)
<L>=1033 for ATLAS and CMS (optimistic?)
<L>=21032 for LHCb (should be possible…)
Ldt = 2.5 fb each for ATLAS and CMS
(if <L> is lower, trigger could be adjusted to have a similar number of b’s)
Ldt = 0.5 fb for LHCb
2009-2011
ATLAS and CMS accumulate Ldt = 30 fb each
end of B physics era and move to 1034 regime (except Bs)
2009-2013
LHCb collect Ldt ≥ 10 fb data by the end of 2013±1
Clara Matteuzzi
QCD 2007 Martina Franca
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The flavour stage
Data samples at the start of the LHC era
• BABAR and Belle will each have collected a
total data sample of approximately 1 ab-1 by
~2008
– 2 ab-1 = 2 x 109 produced B0B0, B+B- pairs
• The Tevatron Run II experiments CDF and DØ
will each have collected ≤ 8 fb-1 by ~2009
CDF and D0, well understood detectors
Clara Matteuzzi
QCD 2007 Martina Franca
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b - physics at the LHC
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
– to 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 second
at a low luminosity of 21032 cm–2s–1
Clara Matteuzzi
QCD 2007 Martina Franca
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The LHCb spectrometer
Special features:
a dedicated trigger and Particle Identification
Vertex
Locator
(Silicon)
RICH counters
Tracking
p/K/p Identification
Clara Matteuzzi
Dedicated to b physics
Works at L=2x1032 cm-2 sec-1
1.9 <  < 4.9 or
15 <  < 300 mrad
Calorimeters
QCD 2007 Martina Franca
Muon
System
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The LHC experiments
Central detectors | η | < 2.5
CMS
ATLAS
b physics trigger:
high pt leptons (6-7 GeV/c  , 12 GeV e)
no hadronic trigger
Mostly b physics with J/Y and rare decays with leptons
(and at low luminosity)
Clara Matteuzzi
QCD 2007 Martina Franca
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Particles Identification in LHCb
•
•
Efficient hadron PID crucial for many channels.
Calibration of K/p PID on data will be performed
using the D*+D0p+, D0 K+p- decay chain
Ex. The Bh+h- channels
ππ
hypothesis
πK
hypothesis
No PID
With PID
πK
hypothesis
Clara Matteuzzi
KK
hypothesis
QCD 2007 Martina Franca
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Is there New Physics in B decays ??
(after all, the CKM picture of CPV does not account for the presence of matter in
the Universe…)
•
•
Some quantities very sensitive to NP are yet to be measured or
lacking precise measurement
Four examples
.
c  arg(Vts)-p via phase of Bs mixing
•
2.
CKM fit prediction is very precise
Branching ratios of rare decays
•
3.
Expect large contributions from NP models
Angular distributions
•
4.
Sensitive to non-SM operators in interactions
g  -arg(Vub)
•
•
Tree processes assumed free of NP
Comparison with measurements from loop processes can reveal NP
Clara Matteuzzi
QCD 2007 Martina Franca
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s from Bs  J/  decays
Clara Matteuzzi
QCD 2007 Martina Franca
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s from Bs  J/  decays
SU(3) counterpart of Bd→J/Ks and measures the Bs- Bs mixing phase
The phase of the oscillation in the SM is given by:
sSM  -2  arg (Vts)  -2c = -22 ~ -0.04
very small , so very sensitive to NP
Prediction from a global fit to CKM measurements (UT fit):
s = -0.037± 0.002
Recent D0 measurement:
+0.14
s = -0.79±0.56(stat) - 0.01 (syst)
– Note: no Bs produced in B factories
Clara Matteuzzi
QCD 2007 Martina Franca
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s from Bs  J/  decays
Bs(Bs)→J/ψ(μ+μ-)φ(K+K-) can proceed directly or through mixing
Bs0
Bs0
Bs0
Measure time dependent CP asymmetries
Need flavour tagging
Clara Matteuzzi
Proper time resolution
QCD 2007 Martina Franca
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Bs→J/ψ(µ+µ-) Φ(K+K-) golden channel
High branching ratio (3x10-5), good experimental signature
Final states with leptons: lepton trigger very effective
for ATLAS, CMS and LHCb
However
J/ is not a pure CP eigenstate
Full decay topology analysis is needed to determine CP even and CP odd states
J/(CP = +1) / J/ (CP = ) (LJ/- = 0, 2 vs LJ/- = 1)
Total
CP-even
CP-odd
Clara Matteuzzi
LHCb
QCD 2007 Martina Franca
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Bs→J/ψ(µ+µ-) Φ(K+K-) golden channel
Time dependent CP asymmetries in Bs, Bs  J/  decays need :
1. Flavour tagging:
opposite side (O.S.) : lepton, jet-charge and kaon
same side (S.S.) : “slow” kaon from the fragmentation
eff = tag(1  2wwrong)2 [10]
O.S.
ATLAS
CMS
LHCb
e

K
Jet
0.25 0.68

3.63
under investigation
0.46 0.70 1.64
1.04
Clara Matteuzzi
QCD 2007 Martina Franca
S.S.
K
“combined”


=4.56
2.71
N.N. = 7.08
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NB: worse resolution =
2.Good proper time resolution:
more dilution in the CP
Bs-Bs oscillation has to be well resolved asymmetries
-good that ms is not too big
-resolution function must be well understood
measuring lifetimes, oscillation plot with Dsp etc.
Proper time resolutions
 [fs]
ATLAS
83
Clara Matteuzzi
CMS
77
LHCb
36
QCD 2007 Martina Franca
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3. Good mass and vertex resolutions
Bs mass resolutions and Background/Signal ratios
m [MeV/c2]
B/S
ATLAS
16.5
0.25
CMS
14
0.33
LHCb
14
0.12
with J/ mass constraint
without mass constraint
Clara Matteuzzi
QCD 2007 Martina Franca
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Event yields from the “2008” run
Numbers of reconstructed J/ and those effectively flavour tagged
Nrec
Nreceff-tag
Clara Matteuzzi
ATLAS CMS LHCb
23 k
27k
33 k
1.0 k
?
2.3 k
QCD 2007 Martina Franca
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Sensitivity to Φs and ΔГs
With 2008 data
(s)
(s)/s
ATLAS CMS
0.158
?
0.41
0.13
LHCb
0.042
0.12
LHCb: BSM effect down to the level of SM can be
excluded/discovered with the 2008 data
(J/ , c , DsDs can be added. No angular analysis needed, but smaller statistics)
With > 2009 data
ATLAS and CMS: (s) ≈ 0.04 with  L dt = 30 fb data
LHCb:
stat(s) ~ 0.01 with  L dt = 10 fb
By ~2013, SM prediction of s tested to a level of ~5
Clara Matteuzzi
QCD 2007 Martina Franca
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Φs : sensitivity to New Physics
From Z. Ligeti et al hep-ph/0604112
Allowed regions CL > 0.90, 0.32, 0.05
• One nominal LHCb year (2 fb-1):
(s)= 0.023 ( UT fit value: -0.037)
• The measurement can be interpreted via
a parametrization of NP effects
Then ms and s can be written:
180o
2006 with first ms
measurement
90o
s
Allowed
region
0o
0.5
180o
ms  m
SM
s
s  
SM
s
hs
2.5
s= 0.04±0.03
1  hs exp(2i ) s
 arg1  hs exp2i s 
1.5
90o
s
LHCb, L=2fb-1
0o
0.1
0.3
0.5
24
Clara Matteuzzi
QCD 2007 Martina Franca
hs
24
Search for rare B decays
Clara Matteuzzi
QCD 2007 Martina Franca
25
Search for Bs  +–
SM expectation:
BR(Bs→µ+µ-) = (3.4±0.4) x 10-9
BR(Bd→µ+µ-) = (1.0±0.5) x 10-10
SM
World best limit by Dø:
BR(Bs→µ+µ-) < 7.5 x 10-8@90%CL
In Supersymmetry:
Large contributions in some SUSY
models
BR(Bd,s→µ+µ-) could be very
sensitive to high values of tan β.
Clara Matteuzzi
QCD 2007 Martina Franca
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Search for Bs  +–
Final states with leptons: lepton trigger very effective
for ATLAS, CMS and LHCb
Main issue is background rejection:
bX + bX
Bc± → J/ψ(µ+µ-)µ±ν
Bpp, Kp, etc.
BX, etc.
+ isolation in pT, etc.
Adressed by
excellent mass resolution
vertex resolution and
particle ID
Bs mass resolutions Bs
m [MeV/c2]
Clara Matteuzzi
ATLAS
77
CMS
36
QCD 2007 Martina Franca
LHCb
18
27
Search for Bs  +–
With 2008 data assuming the SM Br = ~3.510
ATLAS , CMS
Br (B  μμ) <~510 (90%CL)
LHCb limit on BR at 90% CL
LHCb:
(only bkg is observed)
BSM contribution down
to the level of SM can be
excluded/discovered.

Expected CDF+D0 Limit 2x10-8

SM prediction
Uncertainty in
bkg prediction

Integrated Luminosity (fb)
Clara Matteuzzi
LHCb uses “distributions”
for signal and background…
QCD 2007 Martina Franca
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Search for Bs  +–
With > 2009 data
ATLAS and CMS:  L dt = 30 fb, <~610 (90%CL)
(They plan to continue this programme at L=1034, 4 in one year)
LHCb:  L dt = 10 fb, >5 observation for SM Br
Expected final (8 fb-1) from Tevatron at 90% CL : < 2·10-8
LHCb uses “distributions” for signal and background…
Clara Matteuzzi
QCD 2007 Martina Franca
29
Sensitivity to Bs  +–
ATLAS performance summary for B  
LHCb sensitivity
BR (x10–9)
(signal+bkg is observed)
5 observation
SM prediction
3 evidence
ATLAS sensitivity as a
function of integrated
luminosity expected to be
delivered in three years
after LHC start.
Clara Matteuzzi
Integrated luminosity (fb–1)
1 year @ LHCb
QCD 2007 Martina Franca
30
Sensitivity by LHCb
BR(Bs→µ+µ-) in CMSSM as a
Function of gaugino mass
10-6
D0 limit
10-7
10-8
SM
10-9
Clara Matteuzzi
QCD 2007 Martina Franca
31
Search for rare B0  K*0 decays
Clara Matteuzzi
QCD 2007 Martina Franca
32
Search for B0  K*0 decay
SM processes contributing to decay:
BR(B0→lls) = 4.5x10-6
BR(B0→llK) = 0.5x10-6
BR(B0→K*μ+μ-) = ~1.2 x 10-6
Decay seen in B factories, ~ no NP in BR
Decay is very sensitive to extensions of SM :
Analysis of angular distributions allow to extract information
about new Physics.
Clara Matteuzzi
QCD 2007 Martina Franca
33
Observables in B0  K*0μ+μ- decay
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/C9eff
s = μμ mass squared (= q2)
θl = angle between μ and B in
μμ rest frame (AFB angle)
Transverse Asymmetry:
(asymmetry in the spin amplitude of the K*)
K*0 polarisation can be measured
Clara Matteuzzi
QCD 2007 Martina Franca
34
New Physics in
AFB(s) in SM and different
SUSY models:
Bd→ K0*
Non-MFV MSSM with
tan(β) = 5
SUSY I = SUGRA
SUSY II = MIA MSSM
from HEP-ph/0612166
(from Phys.Rev.D61 (2000) 074024)
AT(2)
AFB, theory
s = (m)2 [GeV2]
Clara Matteuzzi
QCD 2007 Martina Franca
35
The B0  K*0 decays
Flavour tag not necessary
in ATLAS and LHCb
(CMS study not yet available)
for one canonical year
10 fb (ATLAS) and 2fb (LHCb)
ATLAS LHCb
(m) [MeV/c2]
51
14
Nsignal
800
7200
B/S
<4.8
~0.5
ATLAS
m
LHCb
45
m
Clara Matteuzzi
55
MeV/c
QCD 2007 Martina Franca
5
5
MeV/c
36
Forward-backward asymmetry in
Bd→ K0*
LHCb 2 fb-1(one canonical year)
AFB
ATLAS 30 fb-1
+ ATLAS precision @ 30 fb-1
+ Belle 2006
SM model
SM extensions
LHCb 2 fb-1: ~7k evts
B/S<0.5
Zero crossing point
s = (m)2 [GeV2]
σAFB (2fb-1)=1.2 GeV 2
By ~2013, LHCb zero crossing point with 10 fb (s0) = 0.28 (GeV/c2)2
 determine C7eff/C9eff with 7% stat error (SM)
Clara Matteuzzi
QCD 2007 Martina Franca
37
The rare decays
B±→ K±
The rare decays
Bu+→K+ll
H0/A0?
Corrections to unity can be
Large ~10% in models that
Distinguish between lepton
flavors,like interactions involving
neutral Higgs boson
An interesting ratio
Hiller & Krüger, PRD69 (2004) 074020
Clara Matteuzzi
QCD 2007 Martina Franca
39
The ratio RK in LHCb
With 10 fb data
Kee 10 k
K 19 k
By ~2013 LHCb
Clara Matteuzzi
(RK) = 0.043
QCD 2007 Martina Franca
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The CKM angle γ in LHCb
Experimental status:
•From the SM fit using only indirect
measurements: γ=(63.1±4.6)° (UTFit)
•From direct measurements with B→DK decays:
γ=(83±19)° (BaBar and Belle)
LHCb can measure angle γ using various methods
L0 hadron pT trigger, K/p identification: essential
Tree-level processes allow clean extraction of γ
Access interference effects involving the phase between Vub and Vcb


Bs  DsK
B, Bd D(*)K(*), with D0 decaying to:
2 bodies: πK , KK, ππ
3 bodies: KS ππ, KS KK, KS Kπ
4 bodies: K πππ, KK ππ
Processes involving large Penguin contributions are sensitive to New Physics
Bd  p+p– & Bs  K+K–
U-spin approach
Clara Matteuzzi
QCD 2007 Martina Franca
41
g from Bs  DsK
 2 time dependent asymmetries from 4 decay rates:
Bs (Bs)  Ds K , Ds K
 2 tree decays (b→c) and (b→u) of same magnitude 

interfere via Bs mixing:

 large interference effects expected

 insensitive to new physics
 CP asymmetry measures (g+ s),
with s being determined using Bs → J/ 
 needs suppression of Bs Dsπ background
(BR~15 higher)


Fit the 4 tagged, time-dependent rates:
 phase of Ds K =   g  s)
 phase of Ds K =   g  s)
 extract both  and g  s
(Bs  Dsπ also used in fit to constrain other
parameters like mistag rate, Δms, ΔГs)
Expect 5400 signal events with B/S<1 at 90% CL
 g ~ 10° in 1year/2fb-1
Clara Matteuzzi
QCD 2007 Martina Franca

s
c D s
u K –
s
B0s  bs
B0s  bs


 

s K 
u

c
s D s


 
DsK asymmetries 
(5 years, ms=20 ps–1)
Ds–K+
Ds+K–
42
42
g from B±  DK±
–
B


 bu
colour-allowed





–
s
K

u
c
0
D

u

b
B– 
u
colour
suppressed



• “ADS+GLW” strategy:

u D0
c
s
–
K

u
Weak phase difference = g
Magnitude ratio = rB ~ 0.08


 relative rates of B–  DK– and B+  DK+
– Measure
the
decays with neutral D’s observed in final states such as:
K–p+ and K+p–, K–p+p–p+ and K+p–p+p–, 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–p+ and D0  K–p+,
and between D0  K–p+p–p+ and D0  K–p+p–p+
(g) = 5–15 with 2 fb–1
Clara Matteuzzi
QCD 2007 Martina Franca
43
g from
b
B0 
d


•
colour
suppressed


with
Treat


c D 0
u
*0
s
K

d
0
B

0
0
D K*
u D0
c
Weak phase difference =
*0
s
g
d K
b
B0 
d

Magnitude ratio = rB ~
0.4
colour
suppressed


 ADS+GLW

same

method
– So far used only D decays to K–p+, K+p–, K+K–
and p+p– final states
(g) = 7–10 with 2 fb–1
Clara Matteuzzi
Decay mode (+cc)
2 fb–1
yield
Bbb/S
B0  (K+p–)D K*0
3400
<0.3
B0  (K–p+)D K*0
500
<1.7
B0  (K+K–, p+p–)DK*0
600
<1.4
QCD 2007 Martina Franca
44
g from BDK Dalitz analyses
• B±  D(KSp+p–)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:
(g) = 8 with 2 fb–1
• B±  D(KKpp)K±:
– Four-body “Dalitz” analysis
– 1.7 k signal events in 2 fb–1
– Assuming signal only and flat acceptance across Dalitz
plot:
(g) = 15 with 2 fb–1
Clara Matteuzzi
QCD 2007 Martina Franca
45
g from Bpp and BsKK
 large penguin contributions in both decays  sensitive to New Physics
p/K
p/K
Bd/s
p/K
Bd/s
p/K
 measure time-dependent CP asymmetry for Bpp and BsKK
 ACP(t) = Adir cos(Δmt) + Amix sin(Δmt)
 Adir and Amix depend on γ, mixing phases, and ratio of penguin to tree = d eiθ
 exploit “U-spin” symmetry (ds) [R.Fleischer, Phys.Lett. B459, 306 (1999)]
 dππ = dKK and θππ = θKK
4 measurements and 3 unknowns, if mixing phases taken from B0J/KS and BsJ/
Expected sensitivity:
 26k Bpp , 37k BsKK, 135k BKp
 σ(γ) ~ 4° in 2fb-1
Clara Matteuzzi
QCD 2007 Martina Franca
46
The CKM angle γ in LHCb
LHCb performance in g determination with 10 fb
DsK
(g
4.5
DK
pp/KK
ADS GLW+D Dalitz
3.6 3.6
6.7
4
With
a weak assumption
on U-spin symmetry
Could be affected by BSM
ADS=Atwood,Dunietz,Sony
GLW=Gronau,London,Wyler
~ 2013 LHCb tree determination of g   2.4
unaffected by BSM
Clara Matteuzzi
QCD 2007 Martina Franca
47
ALICE heavy-flavour potential
• ALICE combines
electronic (||<0.9),
muonic (4<<2.5),
hadronic (||<0.9) channels
pT of Q-hadron [GeV]
1 year pp 14 TeV @ nominal lumin.
HERA-LHC Workshop
ATLAS/CMS
(b)
100
LHCb
(b)
CERN/LHCC 2005-014
hep-ph/0601164
10
ALICE
(b)
(c)
1
-2
0
ALICE
(c/b)
2
4
6
 of Q-hadron
•ALICE is well-equiped for
heavy-flavour studies
– using several different channels / strategies
– acceptance down low pt at central and forward rapidity
•With 109 events (nominal year):
– ~5% statistical error on total cross sections (c and b)
From A.Dainese (ALICE)
Clara Matteuzzi
QCD 2007 Martina Franca
48
Conclusions
Heavy flavour physics will play a significant role in
deepening our understanding of the Standard Model,
and, should New Physics be found at LHC, it provides
unique tools for probing the flavour structure of the
new particles
The effects of new physics loops can be
seen in rare decay branching fractions and
kinematic distributions and in CP-violating
asymmetries in channels with very small branching
fractions
To this improvements will be fundamental better theoretical
understanding and predictions
Clara Matteuzzi
QCD 2007 Martina Franca
49
Conclusions
It is important that other approaches be followed as well:
1. A Super B-Factory can, in the next decade, provide
high precision measurements as well as results
complementary to those of hadronic experiments
2. Rare K decay experiments
3. Searches for lepton flavor violation
The new generation of experiments
at LHC , and especially LHCb, will extend
the fruitful programs of the
current B Factories and Tevatron
Clara Matteuzzi
QCD 2007 Martina Franca
50
Spare slides
Clara Matteuzzi
QCD 2007 Martina Franca
51
Impact of LHCb on UT
LHCb + LQCD only
2 fb–1 (2010)
10 fb–1 (2014)
• LHCb (2 fb–1, 10 fb–
1):
– LHCb:
– (sin(2)) = 0.02,
0.01
– (g) = 4.2º, 2.4º
– () = 10º, 4.5º
• Lattice QCD (2010,
2014):
(  ) /   7.1%
(  ) /   3.9%
(  ) /   3.6%
( ) /   1.8%
From V. Vagnoni, CKM workshop, Dec 2006
Clara Matteuzzi
QCD 2007 Martina Franca
– 40, 1000 Tflop year
– ()/ = 2.5%, 1.5%
• Central values:
– SM assumed
(just for illustration)
52
CKM matrix and the unitarity triangles




The CKM matrix is complex and unitary: V†CKM VCKM = 1
Unitarity gives relationship between rows and columns:  Vij Vik* = 0 (j  k)
The 6 relations can be represented as 6 unitarity triangles in the complex plane
The area of each triangle corresponds to the amount of CP violation in the
transition of the quarks involved
 There are 6 triangles, but only 2 have sides of similar length (un-squashed)
bd
Vud Vub*  VcdVcb*  VtdVtb*  0
Im
VudVtd*  VusVts*  VubVtb*  0
Im

Vtb*Vtd
Vub* Vud
Vub* Vtb

g
*
cb
V Vcd

tu
Vud* Vtd
c
gc
Re
Vus* Vts
Re
 Rescale the unitarity triangles by VcdVcb*
Clara Matteuzzi
QCD 2007 Martina Franca
53
Completing the program on B Physics…
Precise measurement of B0s-B0s mixing:
mixing phase s and ms, s
BsDsp, …
BsJ/, BsJ/(’)
Search for effects of NP appearing in suppressed and rare
exclusive and inclusive B decays
B(s)0Xg, B0K*0l+l-,
bsl+l-, Bs...
Precise γ determinations including processes only at
tree-level, in order to disentangle possible NP
contributions
BsDsK,
B0D0K*0, BDK,
B0pp & BsKK, …
Other measurements of CP phases in different channels
to over-constrain the Unitarity Triangles and to search
for NP contributions in loop decays
B0Ks, Bs, ...
B0p, B0, …
Clara Matteuzzi
QCD 2007 Martina Franca
54
54
B triggers at LHC in one slide
• ATLAS and CMS limited bandwidth for b trigger (5-10% at low L)
• ATLAS: L1 (100kHz) μ pairs or single μ (p >6GeV) with R.O.I. em+jets info
T
HLT (100Hz) with r.o.i. or full scan inside inner detector: jets for
hadronic channels, em for channels with e or γ, muons if a second muon is
missed by L1; reconstruct intermediate resonances
• CMS: similar + partial track reco in r.o.i. and B inv mass
• LHCb: L1(1MHz) is called L0(!)
μ, e,γ and h in HCAL+ pile-up system
HLT (2kHz) based on alleys with partial reco
G.V. +
pT,ET
Event type
hadrons
3.8
Exclusive B candidates
B (core program)
electrons
2.8
High mass di-muons
J/, bJ/X (unbiased)
muon
1.1
D* candidates
2muon
1.3
Clara Matteuzzi
Inclusive
b (e.g. b)
QCD 2007 Martina
Franca
Physics
Charm
B (data mining)
55