LHC
The Energy Frontier
LHCb
ATLAS
CMS
Chris
Parkes,
Chris
Parkes GridPP 8, April 2012
ALICE
1
Two Routes to New Physics
• Direct Production
• Indirect Effects
E=mc2
b
New particles
• Simpler to
interpret
• Probes masses
<E
Chris Parkes
• Model dependent
interpretations
• Probes very high
mass scales –
virtual new particles
2
Contents: Selected new results
• LHC Status
– 2011 data and 2012 expectation
• Heavy Ions (mainly ALICE)
– Suppression/enhancement of particle rates
• Direct Production (mainly ATLAS/CMS)
– The ‘H’ word
– Electroweak / Top physics
– SUSY
• Indirect effects (mainly LHCb)
– Rare Decays
– CP Violation - charm
Chris Parkes
Sources:
Moriond
E’weak,
LHCC
3
LHC: The New Improved Energy
Frontier
Chris
Parkes,
Chris
Parkes GridPP 8, April 2012
4
Mike Lamont, LHCC
2011 – recap
75 ns
50 ns
Scrubbing
Increase number
of bunches
Initial
commissioning
Squeeze
further
25 ns
test
Increase
bunch
intensity
Reduce
beam size
from
injectors
5
•
•
LHC Performance
LHC shows excellent performance
First two years of physics
• Recorded 40 pb-1 in 2010 at 7 TeV + Pb-Pb
• Recorded 5 /1 fb-1 in 2011 at 7TeV + Pb-Pb
• 2012 – now restarted at 8 TeV
Power of Grid:
All collected data reconstructed and many results on full samples6
2012 LHC schedule Q1/Q2
First Collisions
Aims for year:
ATLAS/CMS – need max luminosity
many interactions per bunch crossing
>15 fb-1 (3x 2011)
LHCb – need seconds !
small number interactions per bunch
> 1.5fb-1
ALICE – heavy ions
First proton – lead collisions
7
Mike Lamont, LHCC
2012 LHC schedule Q3/Q4
Protonlead
Special
runs
Followed by long shutdown to move to ~14 TeV
8
Heavy Metal Frontier
Lead Ions
Chris
Parkes,
Chris
Parkes GridPP 8, April 2012
9
Hadrons suppressed but photons
shine !
Hadrons up to pT 100 GeV/c are suppressed
Photons up to ET 80 GeV are not
10
LHC: The Energy Frontier
Direct Production
Chris
Parkes,
Chris
Parkes GridPP 8, April 2012
11
Chris Parkes
12
Higgs 101
1) The last undiscovered particle in the Standard Model
Standard Model Particles
– Higgs Mechanism gives masses to the W & Z
Chris Parkes
Higgs boson,
spin=0
Electric charge 0
13
Higgs 101
1) The last undiscovered particle in the Standard Model
– Higgs Mechanism gives masses to the W & Z
2) The mass of the Higgs boson is not predicted
– The rate of production (cross-section) is
predicted if you know the mass
Higgs boson
Mass = ?
Chris Parkes
14
Higgs 101
BR
3) The Higgs boson has lots of possible decay modes
– It prefers to decay to the heaviest thing available
– Couples to mass
– But easier to find if low background rates
– Best channel changes with Higgs mass
Chris Parkes
15
Standard Model Higgs ?
Combination of many decay channels with FULL 2011 data sample
95% CL Limit on s/sSM
•
10
ATLAS Preliminary
2011 Data
ò
Obs.
Exp.
±1 s
±2 s
-1
Ldt = 4.6-4.9 fb
s = 7 TeV
1
10-1
CLs Limits
100
200
300
400
500
600
mH [GeV]
1) Black solid line below 1: excluded.
Observed number of events less than would
have if the Higgs had that mass
9
16
Standard Model Higgs ?
95% CL Limit on s/sSM
• Zoom in on interesting region
ATLAS Preliminary
10
Obs.
Exp.
±1 s
±2 s
2011 Data
ò
-1
Ldt = 4.6-4.9 fb
s = 7 TeV
1
-1
10
CLs Limits
110 115 120 125 130 135 140 145 150
mH [GeV]
2) Black dashed line : expected if no Higgs
Black solid > black dashed = hint of a Higgs signal
17
Standard Model Higgs ?
• Black line –
~probability of Higgs
at that mass
• Sensitivity comes
from ϒϒ channel
• ATLAS/CMS
compatible
• New Tevatron result
– also compatible
CMS Expected exclusion 114.5 - 543 GeV
CMS Observed exclusion 127.5 - 600 GeV
18
Narrowing in on the Higgs
• Black line – From
Indirect Effects:
top mass and
(new) Tevatron W
mass
• Yellow blocks –
excluded by direct
searches
Indirect Effects: Prediction is from Electroweak resultsW mass and top mass
Chris Parkes
19
Electroweak
stotal [pb]
Cross-sections of Electroweak processes
105
ATLAS Preliminary
-1
35 pb
ò
35 pb-1
104
-1
-1
L dt = 0.035 - 4.7 fb
s = 7 TeV
Theory
Data 2010
Data 2011
103
102
1.0 fb-1
0.7 fb-1
4.7 fb-1
1.0 fb-1
10
4.7 fb-1
W
LHC status
Z
tt
t
WW
WZ
ZZ
20
W and Z Production
• W/Z cross-section ratio
– sensitive test of SM at LHC
• W Charge Asymmetry
W  W

W  W



– changes sign in LHCb region: constraints on the low x
quark content of the protons at high q2.

ATLAS/CMS
21
Top Quark
Chris Parkes
22
Top Quark
Top quark spin
correlations measured for 1st time
Chris Parkes
23
Top Quark
Top quark mass
approaching Tevatron
precision
Chris Parkes
24
Supersymmetry (SUSY) 101
Propose new symmetry of nature: Supersymmetry
Spin ½ Fermions (quarks, leptons)  spin 0 boson superpartner
Spin 1 Bosons  spin ½ fermion superpartner
SUSY not an exact symmetry
Mass of SUSY particles ≠Mass of normal particles
Since none discovered yet
25
SUSY Motivation
2. SUSY cancels
divergences in SM
1/Strength
1. SUSY allows unification of the forces
Log Energy GeV
3. Lightest SUSY particle (LSP)
is candidate for dark matter
Most models LSP is stable
neutralino
4. SUSY provides a theoretical route to include gravity in
“standard model”, and needed in string / M-theory
26
SUSY: theoretically beautiful and convenient – but is it true ?
SUSY + Exotics Searches Summary
ATLAS – many analyses with FULL 2011 Luminosity
Optimal use of delivered data: Enlarge range of “experimental
topologies”
look at as many “experimental topologies” as possible
Then make happy our friend theorists:
translate results in constraints to large variety of models
F. Cerutti - LNF-INFN
27
SUSY + Exotics Searches Summary
Good Fraction of analyses updated with FULL
2011 Luminosity
SUSY is alive but she
has a
headache
Optimal use of delivered data: Enlarge range of “experimental
topologies”
look at as many “experimental topologies” as possible
Then make happy our friend theorists:
translate results in constraints to large variety of models
F. Cerutti - LNF-INFN
28
Muon System
RICH Detectors
Vertex
Locator
Beyond The Energy Frontier
Indirect Effects
Interaction
Point
Calorimeters
Chris
Parkes,
Chris
Parkes GridPP 8, April 2012
Tracking System
29
Rare Decays: Bsμ+μ-
SM prediction 3.2 x 10–9
• Very rare decay – enhanced rate by new physics
–
LHCb rate < 4.5 x 10–9 (95%CL), CMS rate < 7.7 x 10–9 (95%CL), ATLAS < 22 x 10–9 (95%CL)
• New physics SUSY models with
large tan β ~ ruled out
green – allowed regions
black/red – exclusion limits from CMS
yellow - exclusion region from LHCb Bs→μμ result
N. Mahmoudi
Chris Parkes
30
Most rare decay ever seen !
• B+ → π+μ+ μ–
– First observation
• 25±6 events
• 5.2 σ significance
Beyond the Energy Frontier
0
B
→
*0
+
–
K μμ
- Constraining new
physics up to 10TeV
Chris Parkes
31
Matter anti-matter (CP violation) 101
Charge Inversion
Particle-antiparticle
mirror
C
P
Parity
Inversion
Spatial
mirror
CP
32
CP Violation Discoveries
• Strange Quark System (Kaons)
– Discovery of CP Violation
• Beauty Quark systems (B)
– CP violation theory in CKM matrix
– Also Bs, see next slide
• Charm System (D)
– Is there CP Violation in Charm quarks ?
– Predicted to be very small in SM
– Good way of searching for New Physics ?
Chris Parkes
33
Bs Matter Antimatter Asymmetry
ArXiv:1202.6251v1, Feb 2012
B
6σ
Asymmetry
Bs
3.3σ
Asymmetry
Chris Parkes
B
Bs
FIRST CP
34
CP Violation in Bs → J/ψϕ
1 fb-1, LHCb-CONF-2012-002
• Powerful analysis to look for New Physics
• Had been hints from TeVatron – but more
precise LHC results give SM value
Chris Parkes
35
LHCb LHCc
c
• LHCb was designed for b-quark studies
• But also ideal for studies of slightly shorter
lived c quark, and 20 times more events
• CP Violation in charm sector (was) predicted
to be very small in Standard Model < 0.1 %
• Bigger than this New Physics !
e.g.
Chris Parkes
36
CP Violation: Problem 1 – Initial Condition
• Technical Scale Drawing of LHC Collision
Proton
(Matter)
Proton
(Matter)
• Start with matter and no antimatter
• Ending with more matter than antimatter is not a surprise
Take difference in CP Violation between two decays
Chris Parkes
37
CP Violation: Problem 2 – Detector
• Particles bend in magnetic Field
+ve charge
-ve charge
• So if matter goes to a +ve particle and antimatter to –ve
• Go to different parts of detector – can fake CP violation
1)Take difference in CP Violation between two decays
2)Reverse Magnetic Field Periodically
3)Choose a symmetric decay
Chris Parkes
38
Direct CP Violation in Charm


A CP (K K ) 


A CP (   ) 








( D  K K )  ( D  K K )
( D  K K )  ( D  K K )








( D    )  ( D    )
( D    )  ( D    )
A RAW ( f )  A CP ( f )  A Detector ( f )  A Production
What we
measure
Chris Parkes
What we
want
What we
What we
don’t want (1) don’t want (2)
39
Direct CP Violation in Charm


A CP (K K ) 


A CP (   ) 








( D  K K )  ( D  K K )
( D  K K )  ( D  K K )








( D    )  ( D    )
( D    )  ( D    )
A RAW ( f )  A CP ( f )  A Detector ( f )  A Production
What we
measure
What we
want
What we
What we
don’t want (1) don’t want (2)
Symmetric Final State
Chris Parkes
40
Direct CP Violation in Charm


A CP (K K ) 


A CP (   ) 








( D  K K )  ( D  K K )
( D  K K )  ( D  K K )








( D    )  ( D    )
( D    )  ( D    )
A RAW ( f )  A CP ( f )  A Detector ( f )  A Production
What we
measure
What we
want
What we
What we
don’t want (1) don’t want (2)
Symmetric Final State
Magnetic Field
Chris Parkes
41
Direct CP Violation in Charm




A CP  A CP (K K )  A CP (   )
A RAW ( f )  A CP ( f )  A Detector ( f )  A Production
What we
measure
What we
want
What we
What we
don’t want (1) don’t want (2)
Symmetric Final State
Magnetic Field
Take Difference of final states
Chris Parkes
42
 A CP
Direct CP Violation in Charm
Phys. Rev. Lett. 108, 111602 (2012), 12th March 2012
 A CP   0 .82  0 .21 ( stat .)  0 .11 ( syst .) %
• High Statistics
– 1.4M K+K-, 0.4M π+π-
Chris Parkes
43
 A CP
Direct CP Violation in Charm
 A CP   0 .82  0 .21 ( stat .)  0 .11 ( syst .) %
New Prelim Result, 28th February
 A CP   0 .62  0 .21 ( stat .)  0 .10 ( syst .) %
• Confirmation of Effect
• World Average 3.7 σ
Chris Parkes
44
 A CP
Direct CP Violation in Charm
Interpretation: M. Gersabeck, S. Borghi, CP
http://arxiv.org/abs/1111.6515
Average: Marco Gersabeck
• First evidence of CP violation in charm sector
Chris Parkes
45
New Physics ?
• CP Violation in charm sector (was) predicted
to be very small in Standard Model < 0.1 %
• We measure 0.82±0.24% (on difference)
• New Physics ?
• Well maybe not…
Chris Parkes
46
• Pb – Pb collisions
2011 Summary
– Particle suppression / enhancement in new state of matter
• Higgs:
– Tantalising hints of SM Higgs around 125 GeV
• We will know this year
• SUSY:
– No signs of her yet in direct production or rare
decays
• Rare Decays:
– Most rare decay ever seen
• CP Violation:
– First evidence for CP violation in charm sector
• Compatible with SM ?
Chris Parkes
47
• Pb – Pb collisions
2011 Summary
– Particle suppression / enhancement in new state of matter
• Higgs:
2012
– Tantalising hints of SM Higgs around 125 GeV
• We will know this year
• SUSY:
New World record energy
– No signs of her yet in direct production or rare
decays
• Rare Decays:
Expect
more
– Most rare
decay lots
ever seen
data for
Grid to reconstruct
• CP Violation:
– First evidence
for CPPhysics
violation in?charm sector
New
• Compatible with SM ?
Chris Parkes
48