(forward look at) physics at the lhc
DESCRIPTION
(Forward Look at) Physics at the LHC. Outline The LHC – quick introduction/reminder The detectors Higgs physics – in the SM and the MSSM Supersymmetry: Sparticles (squarks/gluinos/gauginos) Precision measurements Other (possible) new physics TeV-scale gravity Current status Summary. - PowerPoint PPT PresentationTRANSCRIPT
LHC Physics 1P. Sphicas/ISHEP2003
(Forward Look at) Physics at the LHC(Forward Look at) Physics at the LHC
Outline The LHC – quick introduction/reminder The detectors Higgs physics – in the SM and the MSSM Supersymmetry:
Sparticles (squarks/gluinos/gauginos) Precision measurements
Other (possible) new physics TeV-scale gravity Current status Summary
Paris Sphicas
CERN and Univ. of Athens
International School on High Energy Physics
Crete, October 2003
P. Sphicas/ISHEP2003
SupersymmetrySupersymmetry
Sparticles
LHC Physics 3P. Sphicas/ISHEP2003
SUSYSUSY Huge number of theoretical models
Very complex analysis; MSSM-124 Very hard work to study particular scenario
assuming it is available in an event generator To reduce complexity we have to choose some “reasonable”,
“typical” models; use a theory of dynamical SYSY breaking mSUGRA GMSB AMSB (studied in less detail)
Model determines full phenomenology (masses, decays, signals)
LHC Physics 4P. Sphicas/ISHEP2003
SUGRASUGRA Five parameters
All scalar masses same (m0) at GUT scale
All gaugino masses same (m1/2) at GUT scale tan and sign() All tri-linear Higgs-sfermion-sfermion couplings common value
A0 (at GUT scale)
Full “particle table” predictable 26 RGE’s solved iteratively Branches: R parity (non)conservation Extensions: relax GUT assumptions (add parameters)
LHC Physics 5P. Sphicas/ISHEP2003
Sparticles in SUGRASparticles in SUGRA Contours of fixed g/q and / mass~ ~ ~ ~
22/1
20
2/1
6)~(
3)~(
mmqm
mgm
2
2/120
2/1022/1
01
)15.0,5.0()~,~(
;)~,~( ;2/)~(
mmm
mmmm
RL
LHC Physics 6P. Sphicas/ISHEP2003
SUSY @ LHCSUSY @ LHC Simplest SUSY
A SUSY factory
Gauginos produced in their decay; example: qL2
0qL
~ ~
Msp(GeV) (pb) Evts/yr500 100 106-107
1000 1 104-105
2000 0.01 102-103
M=500 GeV
LHC Physics 7P. Sphicas/ISHEP2003
SUSY decays (I)SUSY decays (I) Squarks & gluinos produced together with high
Gauginos produced in their decays; examples: qL2
0qL (SUGRA P5)
q g q 20qq (GMSB G1a)
Two “generic” options with 0:
(1) 20 1
0h (~ dominates if allowed)
(2) 20 1
0+– or 20 +–
Charginos more difficult Decay has or light q jet
Options: Look for higgs (to bb) Isolated (multi)-leptons
~
–
~ _~ ~
~
LHC Physics 8P. Sphicas/ISHEP2003
SUSY decays (II): rich cascadesSUSY decays (II): rich cascades
Heavy gluino branching ratio chart
Heavy gluino branching ratio chart
Large amount of Missing ET
from LSP and W/Z, b-jets) ,e from chargino, neutralino if tan is not too large and decays to stau -> tau dominate;also from Z,W
~
LHC Physics 9P. Sphicas/ISHEP2003
SUSY decays (III): characteristicsSUSY decays (III): characteristics
LHC Physics 10P. Sphicas/ISHEP2003
Spectacular signatures expectedSpectacular signatures expected
Full simulation in CMS detector yetwith GEANT3
Squark-gluino production
4 hard b-jets +2 hard jets
+2 LSP + > 4(+ leptons)
4 hard b-jets +2 hard jets
+2 LSP + > 4(+ leptons)
LHC Physics 11P. Sphicas/ISHEP2003
SUSY mass scaleSUSY mass scale Events with 4jets + ET
miss
Clean: S/B~10 at high Meff
Establish SUSY scale (20%)
Meff PT, jj1
4
ETmiss
Effective mass “tracks”SUSY scale well
Meff (GeV/c2)
MS
US
Y (
GeV
/c2 )
LHC Physics 12P. Sphicas/ISHEP2003
SUGRA: the (original) five LHC pointsSUGRA: the (original) five LHC points Defined by LHCC in 1996
Most of them excluded by now… Easy to bring them back
Points 1,3,5: light Higgses LEP-excluded (3; less for 1,5) Restore with larger tan
Points 1&2: Squark/gluinos ≈ 1TeV
Point 4: at limit of SB Small , large mixing Heavy squarks
Point 5: cosmology-motivated Small m0light sleptons
increase annihilation of reduce CDM
P M0 M1/2 A0 tan s()
1 400 400 0 2 +
2 400 400 0 10 +
3 200 100 0 2 –
4 800 200 0 10 +
5 100 300 300 2.1 +
LHC Physics 13P. Sphicas/ISHEP2003
Experimentally: spectacular signaturesExperimentally: spectacular signatures “Prototype”: 2
0 10+–
Straightforward:
dileptons + ETmiss
Example from P3 SM even smaller with b’s Also works at other points But additional SM (e.g. Z0)
M measurement easy Position of edge; accurate
Point excluded, but main point (dilepton-edge) still valid at other points
~ ~
M(+-) (GeV/c2)
Eve
nts/
(2 G
eV/c
2 )
LHC Physics 14P. Sphicas/ISHEP2003
Dileptons @ other pointsDileptons @ other points Multi-observations
Main peak from 201
0+–
Measure m as before Also peak from Z0 through
201
0Z0 Due to heavier gauginos P4 at “edge” of SB
small 2 (a) ± and 0 are light
(b) strong mixing between gauginos and Higgsinos
At P4 large Branching fractions to Z decays: e.g. B(31.2Z0)≈1/3; size of peak/PT(Z)info on masses and
mixing of heavier gauginos (model-dependent)
~
~
~
~
~
~ ~
M(+-) (GeV/c2)E
vent
s/(4
GeV
/c2 )
LHC Physics 15P. Sphicas/ISHEP2003
SUGRA reachSUGRA reach Using all signatures
tan=2;A0=0;sign()=–
But look at entire m0-m1/2 plane
Example signature: N (isolated) leptons +
≥ 2 jets + ETmiss
5 (=significance) contours
Essentially reach is ~2 (1) TeV/c2 for the m0 (m1/2) plane
CMS100 fb–1
LHC Physics 16P. Sphicas/ISHEP2003
Varying tanVarying tan modes eventually become important
At tan>>1 only
2-body 20 decays
(may be): 20 1
0
Visible e excess over SM;
for dilepton edge: need mass
~~ ~ ~
LHC Physics 17P. Sphicas/ISHEP2003
The other scenario: The other scenario: 2200 11
00hh Followed by hbb: h discovery at LHC
E.g. at Point 1, 20% of SUSY events have hbb But squarks/gluinos heavy (low cross sections)
b-jets are hard and central
–
Expect large peak in (b-tagged) di-jet mass distribution
Resolution driven by jet energy measurement
Largest background is other SUSY events!
–
LHC Physics 18P. Sphicas/ISHEP2003
Building on the hBuilding on the h In analogy with adding jets to 2
0 10+–
Select mass window (e.g. 50 GeV) around h Combine with two highest ET jets; plot shows min. mass Again, use kinematic limits
Case shown: max ≈ 550 GeV/c2
Beyond this: Model dependence
LHC Physics 19P. Sphicas/ISHEP2003
Observability of decays into hObservability of decays into h Examples from CMS (tan=2&10)
LHC Physics 20P. Sphicas/ISHEP2003
New set of benchmarks currently in use Account for LEP, bs,g–2
and cosmology Example: “BDEGMOPW”
(Battaglia et al, hep-ph/0112013)
Recent: Snowmass points & slopes; working on updates
Overall reachOverall reach
Benchmark Point
# sp
artic
les
foun
d
SquarksSleptonsCharginos/neutralinosHiggses
Gluino
LHC Physics 21P. Sphicas/ISHEP2003
SUSY parameters; SUGRASUSY parameters; SUGRA
Point/Lumi m0 (GeV) m1/2 (TeV) tan s
P1 @100fb-1 400±100 400±8 2.00±0.08 ok
P2 @100fb-1 400±100 400±8 10±2 ok
P4 @100fb-1 800±50 200±2 10±2 ok
P5 @10fb-1 100±4 300±3 ±0.1 ok
Essentially no information on A0 (Aheavy evolve to fixed point independent A0)
LHC Physics 22P. Sphicas/ISHEP2003
RRPP violation violation
W L L E Q L D U L Dijk i j kc
ijk i j kc
ijk icjckc
Non-conservation of leads to 3 new groups of terms (45 terms in total) in SUSY superpotential :
Rp= (-1)3(B-L)+2S
Most challenging for the trigger is the last group – barion number violation:
R-parity violation event In CMS calorimetry
R-parity violation event In CMS calorimetry
-> 3j~
Missing ET is reduced, but still substantial Number of jets increases
ET jet (HLT) > 30 GeVET jet (HLT) > 30 GeV
more than in t t more than in t t _
LHC Physics 23P. Sphicas/ISHEP2003
GMSB: NLSP and GMSB: NLSP and 110 0 lifetimelifetime
If NLSP=1,
use TOF (~1ns)
(good for high
lifetimes) Detecting the
10G decay Off-pointing
photons + 10
decays in muon
chambers
~~
P. Sphicas/ISHEP2003
SUSY: precision measurementsSUSY: precision measurements
LHC Physics 25P. Sphicas/ISHEP2003
Example: G1a; same dilepton edge Decay observed:
20 1
0 G+–
Selection is simple: Meff>400 GeV
ETmiss>0.1Meff
Demand same-flavor leptons Form e+e– ++–– e
G2b: very similar to SUGRA 1
0 is long-lived, escapes Decay observed:
20 1
0 +–
Meff>1 TeV; rest of selection as in G1a
GMSB observationGMSB observation
G1a~ ~~
G1b
~ ~
~
~
LHC Physics 26P. Sphicas/ISHEP2003
SUSY parameter measurements (G1a)SUSY parameter measurements (G1a) G1a: endpoint in
M() 3 parameters Events with two leptons and two photons,
plot min(M()) yields second relation:
Next: evts with only one M()
smaller than endpoint mass Unambiguous id of 2
0 decay Plot lepton-photon mass, two
more structures:
201
2
02
02max )~(
)~(1
)~()~(
1)~(
R
R
MM
MM
MM
)~()~( 01
202
2max MMM
min(M)
GeV7.112)~()~( 01
22 MM R
GeV6.152)~()~( 202
2 RMM
M
LHC Physics 27P. Sphicas/ISHEP2003
SUSY mass measurements (G1a)SUSY mass measurements (G1a) Measurement of edge positions: very accurate
Worse resolution on linear fit (e.g. min(M()) Low luminosity: 0.5 GeV; High lumi: 0.2 GeV (syst).
One can extract masses of 20, 1
0, R Model-independent (except for decay, rate and
interpretation of slepton mass as mass of R)
Next step: reconstruct G momentum Motivation: can then build on 2
0 to reconstruct Mq and Mg
0C fit to 20 G+– (with MG=0)
– Momentum to 4-fold ambiguity Use evts with 4 leptons + 2 photons
– ETmiss fit to resolve solns: min(2):
~
~
~ ~~
~
~~
2
21
2
212
missy
yymissy
missx
xxmissx
E
PPE
EPPE
LHC Physics 28P. Sphicas/ISHEP2003
G1a: masses of squarks and gluinos (I)G1a: masses of squarks and gluinos (I) Decay sought: qgq2
0qqq Select evts with 4 jets (PT>75)
Combine each fully-reconstructed 20 with 2 and 3 jets
This yields peaks at gluino and squark mass (direct) Peak position not a function of jet cut…
~ ~ ~ –
~
LHC Physics 29P. Sphicas/ISHEP2003
G1a: masses of squarks and gluinos (II)G1a: masses of squarks and gluinos (II) Mass distributions can be sharpened
Use correlations in M(jj) vs M(jjj) Statistical errors small
Expect syst. dominance (jet energy
scale)
800<M(jjj)<1000 600<M(jj)<800
LHC Physics 30P. Sphicas/ISHEP2003
Cosmology and CDMCosmology and CDMJ.Ellis et al., hep-ph/0303043
Legend :
older cosmological constraint 0.1 < h < 0.3
2 x
newer cosmological constraint 0.094 < h < 0.129
2 x
is not LSP
excluded by b -> s favored by g – 2 at 2- level
LHC Physics 31P. Sphicas/ISHEP2003
Cosmology, CDM and LHCCosmology, CDM and LHC
LHC Physics 32P. Sphicas/ISHEP2003
SUSY SummarySUSY Summary SUSY discovery (should be) easy and fast
Expect very large yield of events in clean signatures (dilepton, diphoton). Establishing mass scale is also easy (Meff)
Squarks and gluinos can be discovered over very large range in SUGRA space (M0,M1/2)~(2,1)TeV Discovery of charginos/neutralinos depends on model Sleptons difficult if mass > 300 GeV Evaluation of new benchmarks (given LEP, cosmology etc) in
progress
Measurements: mass differences from edges, squark and gluino masses from combinatorics
Can extract SYSY parameters with ~(1-10)% accuracy
P. Sphicas/ISHEP2003
Other new Physics Other new Physics (Or WBSM)(Or WBSM)
LHC Physics 34P. Sphicas/ISHEP2003
Other resonances/signatures (I)Other resonances/signatures (I) New vector bosons
LHC Physics 35P. Sphicas/ISHEP2003
CompositenessCompositeness Usual excess @
high PT(jet) expected Tricky issue:
calorimeter (non)linearity
Analysis proceeds
via angular distribution
Ultimate reach:
comp ~ 40 TeV(depends on understanding
non-linearity @ 1-2% level)
14 TeV300 fb-1
Dev
iati
on f
rom
SM
28 TeV3000 fb-1
Dev
iati
on f
rom
SM
|* cos| 1
|* cos| 1
LHC Physics 36P. Sphicas/ISHEP2003
Excited quarksExcited quarks Search for q*q
P. Sphicas/ISHEP2003
TeV-scale gravityTeV-scale gravity
LHC Physics 38P. Sphicas/ISHEP2003
NaturalnessNaturalness SUSY: the mass protector
MW2~(/)2>>(MW)2; But with SUSY MW
2~(/)|MSP–MP|2
The pro-LHC argument: correction smallMSP~1TeV Lots of positive side-effects:
– LSP a great dark-matter candidate;
– unification easier;
– poetic justice: why would nature miss this transformation? (complete transforms in the Poincare group – only SUSY escapes Coleman-Mandula no-go theorem)
SUSY does not answer why GF~(MW)-2>>(MPL)-2~GN
But it (at least) allows it
LHC Physics 39P. Sphicas/ISHEP2003
TeV-scale gravityTeV-scale gravity The idea of our times: that the
scale of gravity is actually not given by MPL but by MW
Strings live in >4 dimensions. Compactification 4D “SM”. MPL-4 related to MPL-(4+d) via volume of xtra dimensions: MPL-4
2 ~ Vd MPL-(4+d)2+d
Conventional compactification: very small curled up dims, MPL-4~MPL-(4+d)
Vd ~ (MPL-4)–d
Alternative: volume is large; large enough that Vd>>(MPL-(4+d))–d
Then MPL-(4+d) can be ~ TeV (!) “our” Planck mass at log()~19: an
artifact of the extrapolation
LHC Physics 40P. Sphicas/ISHEP2003
Getting MGetting MPL-4PL-4~1TeV~1TeV Can be, if Vd is large; this can be done in two ways:
By hand: large extra dimensions (Arkani-Hamed,Dimopoulos,Dvali)
Size of xtra dimensions from ~mm for d=2 to ~fm for d=6 But gauge interactions tested to ~100 GeV
– Confine SM to propagate on a brane (thanks to string theory) Rich phenomenology
Via a warp factor (Randall-Sundrum)
ds2= g dx dx+gmn(y)dymdyn
– (x: SM coordinates; y: d xtra ones) Generalize: dependence on location in xtra dimension ds2= e 2A(y) g dx dx+gmn(y)dymdyn
– Large exp(A(y)) also results in large Vd
– As an example (RS model), two 4-D branes, one for SM, one for gravity, “cover” a 5-D space – with an extra dim in between
LHC Physics 41P. Sphicas/ISHEP2003
Extra (large) space-time dimensionsExtra (large) space-time dimensions Different models, different signatures:
Channels with missing ET: ETmiss+(jet/) (back-to-back)
Direct reconstruction of KK modes Essentially a W’, Z’ search
Warped extra dimensions (graviton excitations)
Giudice, Ratazzi, Wells (hep-ph/9811291)
Hewett (hep-ph/9811356)
LHC Physics 42P. Sphicas/ISHEP2003
Extra dimensions (I): EExtra dimensions (I): ETTmissmiss+Jet+Jet
Issue: signal & bkg
topologies same; must
know shape of bkg vs
e.g. ETmiss
Bkg: jet+W/Z;
Z; W . Bkg normalized through jet+Z, Z ee and Z events
ETmiss ET
miss
MD=5TeV MD=7TeV
MD (TeV) RD 2 7.5 10 m 3 5.9 200 pm 4 5.3 1 pm
Reach @ 5
Also ETmiss+; MD reach smaller
LHC Physics 43P. Sphicas/ISHEP2003
KK resonances+angular analysisKK resonances+angular analysis If graviton excitations present, essentially a Z’ search.
Added bonus: spin-2 (instead of spin-1 for Z) Case shown*: Ge+e–
for M(G)=1.5 TeV Extract minimum .B for
which spin-2 hypothesis is
favored (at 90-95%CL)
100 fb–1
* B.Allanach,K.Odagiri,M.Parker,B.Webber JHEP09 (2000)019
LHC Physics 44P. Sphicas/ISHEP2003
En passantEn passant TeV-scale gravity is attracting a lot of interest/work
Much is recent, even more is evolving Turning to new issues, like deciding whether a new dilepton
resonance is a Z’ or a KK excitation of a gauge boson In the latter case we know photon, Z excitations nearly
degenerate– One way would be to use W’ (should also be degenerate,
decays into lepton+neutrino)
» But this could also be the case for additional bosons… Example: radion phenomenology
Radion: field that stabilizes the brane distance in the RS scenario. Similar to Higgs. Recent work suggests it can even mix with the Higgs.
– Can affect things a lot Stay tuned, for this is an exciting area
LHC Physics 45P. Sphicas/ISHEP2003
Black Holes at the LHC (?) (I)Black Holes at the LHC (?) (I) Always within context of “TeV-scale gravity”
Semi-classical argument: two partons approaching with impact parameter < Schwarzschild radius, RS black hole RS ~ 1/MP (MBH/MP)(1/d+1) (Myers & Perry; Ann. Phys 172, 304 (1996)
From dimensions: (MBH)~RS2; MP~1TeV ~400 pb (!!!)
Due to absence of small coupling like LHC, if above threshold, will be a Black Hole Factory:
At minimum mass of 5 TeV: 1Hz production rateDimopoulos & Landsberg hep-ph/0106295
Assumptions:
MBH>>MP; in order to avoid true quantum gravity effects… clearly not the case at the LHC – so caution
Giddings & Thomas hep-ph/0106219
LHC Physics 46P. Sphicas/ISHEP2003
Black Holes at the LHC (II)Black Holes at the LHC (II) Decay would be spectacular
Determined by Hawking temperature, TH1/RS~MP(MP/MBH)(1/n+1)
Note: wavelength of Hawking TH (2/TH)>RS
– BH a point radiator emitting s-waves Thermal decay, high mass, large number of decay products
Implies democracy among particles on the SM brane– Contested (number of KK modes in the bulk large)
Picture ignores time evolution
…as BH decays, it becomes lighter hotter and decay accelerates (expect: start from asymmetric horizon symmetric, rotating BH with no hair spin down Schwarz-schild BH, radiate until MBH~MP. Then? Few quanta with E~MP?)More generally: “transplackian physics”; see: Giudice, Ratazzi&Wells, hep-ph0112161
P. Sphicas/ISHEP2003
Beyond the LHCBeyond the LHC
LHC++
LHC Physics 48P. Sphicas/ISHEP2003
Beyond LHC; LHC++?Beyond LHC; LHC++? Clearly, a Linear Collider is a complementary machine
to the LHC Will narrow in on much of what the LHC cannot probe Still a lot to do; e.g. see (and join/work!) LHC-LC study group
http://www.ippp.dur.ac.uk/~georg/lhclc As for LHC, a very preliminary investigation of
LHC at 1035cm-2s-1; LHC at 25 TeV; LHC with both upgrades First look at effect of these upgrades
Triple Gauge Couplings Higgs rare decays; self-couplings; Extra large dimensions New resonances (Z’) SUSY Strong VV scattering
Clearly, energy is better than luminosity Detector status at 1035 needs careful evaluation
LHC Physics 49P. Sphicas/ISHEP2003
Possible LHC upgradesPossible LHC upgrades
LHC Physics 50P. Sphicas/ISHEP2003
LHC vs SLHCLHC vs SLHC
LHC Physics 51P. Sphicas/ISHEP2003
Life at 10Life at 103535 cm cm-2-2ss-1-1
LHC Physics 52P. Sphicas/ISHEP2003
Implications for detectorsImplications for detectors Tracking
LHC Physics 53P. Sphicas/ISHEP2003
Implications for TriggerImplications for Trigger
LHC Physics 54P. Sphicas/ISHEP2003
Expected PerformanceExpected Performance
LHC Physics 55P. Sphicas/ISHEP2003
Life at 25 TeVLife at 25 TeV Charged particle spectra
LHC Physics 56P. Sphicas/ISHEP2003
Higgs at SLHCHiggs at SLHC
LHC Physics 57P. Sphicas/ISHEP2003
Supersymmetry reach @ LHC++Supersymmetry reach @ LHC++ mSUGRA scenario
Assume RP conservation
Generic ETmiss+Jets
Cuts are optimized to get best S2
SUSY/(SSUSY+BSM) In some cases 0-2
leptons could be better Shown: reach given
A0 = 0; tan=10; >0 For 28 TeV @ 1034cm–2s–1
probe squarks & gluinos up to ~ 4 TeV/c2
For 14 TeV @ 1035cm–2s–1 reach is ~ 3 TeV/c2
LHC Physics 58P. Sphicas/ISHEP2003
Strong WW/WZ scatteringStrong WW/WZ scattering “Golden modes” considered
(leptonic decays; e/ only) Numerous channels (WW,
WZ, ZZ). Worst-case (signal vs backgrounds) channel is WZ
Only L=1034cm–2s–1 considered because analysis requires: forward tagging jets and central jet vetoes
large effect from pileup at L=1035cm–2s–1
Like-sign WW & WZ: luminosity needed for 5
observation
LHC Physics 59P. Sphicas/ISHEP2003
Triple Gauge Couplings @ LHC++Triple Gauge Couplings @ LHC++
Z
kZ
Z
Machine
Energy/Lum
kZ
x10-3
Z
x10-3
NLC
0.5 TeV
500 fb-1
1.6 1.3
LHC
14 TeV
100 fb-1
40 1.4
LHC
14 TeV
1000 fb-1
34 0.6
LHC
28 TeV
1000 fb-1
13 0.2
LHC Physics 60P. Sphicas/ISHEP2003
Extra (large) dimensions @ LHC++Extra (large) dimensions @ LHC++ Signatures: the same
Bonus: can extract MD and from (28 TeV) / (14 TeV)
(since ~MD–(+2))
Topology used here:
Jet+missing ET
G
g
LHC Physics 61P. Sphicas/ISHEP2003
Z' reach in LHC++Z' reach in LHC++
Only Z'consideredM(Z')=8 TeV/c2
signal vs Drell-Yan background
Example: with Standard Model Br
Reach in M(Z') is a function of Br(Z')
LHC Physics 62P. Sphicas/ISHEP2003
(Grand) Summary(Grand) Summary Symmetry Breaking in the SM (and beyond!) still not
really understood Higgs missing; LHC (and ATLAS/CMS) designed to find it
Physics at the LHC will be extremely rich SM Higgs (if there) in the pocket
Turning to measurements of properties (couplings, etc.) Supersymmetry (if there) ditto
Can perform numerous accurate measurements Large com energy: new thresholds
TeV-scale gravity? Large extra dimensions? Black Hole production? The end of small-distance physics?
And of course, compositeness, new bosons, excited quarks…
There might be a few physics channels that could benefit from more luminosity… LHC++?
We just need to build the machine and the experiments
P. Sphicas/ISHEP2003
BackupsBackups
LHC Physics 64P. Sphicas/ISHEP2003
Physics: planning vs realityPhysics: planning vs reality
LHC Physics 65P. Sphicas/ISHEP2003
LHC statusLHC status
LHC Physics 66P. Sphicas/ISHEP2003
SUGRA spectroscopySUGRA spectroscopy Basic assumption: mass universality
Scalar masses: m0;
gaugino masses: m1/2;
Higgs masses: (m02+2)1/2
RGE: run masses down
to EWK scale M(squark): large
Increase (due to 3) M(slepton): small increase
(due to 1, 2) Gauginos: gluino is fast-rising; B-ino, W-ino mass decreases Mixing leads to charginos (2) and neutralinos (4)
Higgs: strong top coupling drives ; Symmetry Breaking mechanism arises naturally in mSUGRA(!)
LHC Physics 67P. Sphicas/ISHEP2003
SM Higgs properties IV: couplingsSM Higgs properties IV: couplings At high masses, ratio of HWW to HZZ (2:3)
Straightforward; top decay very difficult
At low masses (i.e. below ZZ threshold) more information
LHC Physics 68P. Sphicas/ISHEP2003
Status: summaryStatus: summary Some delays
Civil engineering etc
“Startup”: Currently defined as 2x1033 cm–2s–1 in August 2006 Expect:
Work on detectors; but once they are understood– SUSY within a week/month
– Higgs within three months (unless some of the Higgses were already produced at LEP)
Later: push to higher luminosity Now turning to computing (resources etc.)
LHC Physics 69P. Sphicas/ISHEP2003
MSSM Higgses: expected LEP reachMSSM Higgses: expected LEP reach Taking 208 GeV and actual luminosity recorded
M(h)M(h)
tan
No mixingMax mixing
M(A)ta
n
LHC Physics 70P. Sphicas/ISHEP2003
Extra dimensions (II): EExtra dimensions (II): ETTmissmiss+photon+photon
Rates much lower than for jet case Channel could be a “confirmation” one Bkgs: +Z, Z& +W, W ; calibrated to Zee
(Z in Bkg)/(Z in ,ee) ~ 6
Reach @ 5 MD (TeV) RD
2 3.7 30 m
LHC Physics 71P. Sphicas/ISHEP2003
Extra (large) dimensionsExtra (large) dimensions Different models, different signatures:
Channels with missing ET: ETmiss+(jet/) (back-to-back)
Results from theory papers based on similar signatures (e.g. gravitino searches); instrumental bkg: same signature
Direct reconstruction of KK modes Essentially a W’, Z’ search
Giudice, Ratazzi, Wells (hep-ph/9811291)
LHC Physics 72P. Sphicas/ISHEP2003
SummarySummary SUSY (if there) will be seen
It will be very difficult to not see SUSY if today’s “natural” parts of SUSY space are natural indeed
Can determine parameters over fairly large part of SUSY space Can perform a few precise measurements
Large com energy: new thresholds Compositeness, new bosons, excited quarks, etc; ~ 40 TeV
Large extra dimensions Can see them for MD up to ~ 5-10 TeV and =2-4
LHC Physics 73P. Sphicas/ISHEP2003
Extra dimensions (III): DileptonsExtra dimensions (III): Dileptons Indirect signal: Drell-Yan
Leptons very clean; composite-
ness-like signature; forward-
backward asymmetry as well Also production
Hewett (hep-ph/9811356)
LHC Physics 74P. Sphicas/ISHEP2003
Determining SUSY parametersDetermining SUSY parameters From the edges of the spectra
@ P5: qLq20qq+–
ATLAS example: 2 isol, OS leptons+≥4jets+ET
miss Combine leptons with 2 harder jets
Similarly, minimum at 270 GeV/c2 Both min & max visible Example shown: e subtracted
~
550
2/1
2
2222~
max
02
01
02
02
M
MMMMM Lq
q
~ ~
M(+–q) (GeV/c2)
LHC Physics 75P. Sphicas/ISHEP2003
Distinguishing 2 & 3-body decaysDistinguishing 2 & 3-body decays Two scenarios can be disentangled directly
From asymmetry of two
leptons:
In analogy with decays
minT
maxT
minT
maxT
PPPP
A
LHC Physics 76P. Sphicas/ISHEP2003
New at LHC: amount of online selectionNew at LHC: amount of online selection
109 Ev/s 109 Ev/s
102Ev/s102Ev/s
99.99 % Lv199.99 % Lv1
99.9 % HLT99.9 % HLT
0.1 %0.1 %
105 Ev/s 105 Ev/s
0.01 %0.01 %
Same hardware (Filter Subfarms) Same software (CARF-ORCA) But different situations
Same hardware (Filter Subfarms) Same software (CARF-ORCA) But different situations
LHC Physics 77P. Sphicas/ISHEP2003
GMSBGMSB Model assumes SUSY broken at scale F1/2 in sector
containing non-SM (heavy) particles This sector couples to SM via “messengers” of mass M Loops involving messengers mass to s-partners
Advantage of model; mass from gauge interactions no FCNC (which can cause problems in SUGRA)
Phenomenology: lightest SP is gravitino (G) SUGRA: M(G)~O(1)TeV, phenomenologically irrelevant GMSB: NSLP decays to G; unstable NLSP can be charged
Lifetime of NLSP “free”: O(m) < c < O(km) Neutral NLSP: lightest combination of higgsinos and gauginos behaves like SUGRA LSP (except for its decay…)
Charged NLSP: R; low tan: degenerate eR,R,R; high tan: R is lightest slepton, others decay to it
~~
~
~ ~ ~ ~~
LHC Physics 78P. Sphicas/ISHEP2003
GMSB parametersGMSB parameters SUSY breaking scale: =F/M N5: # messenger fields tan (ratio of Higgs vev’s) s() (|| fixed from M(Z)) Cgrav (G mass scale factor)
NLSP ~ (Cgrav)2
GMSB “points”* G1: NLSP is 1
0
G1a: c is short (1.2mm) G1b: c is long (1km)
G2: NLSP is G2a: eR, R, 1 short-lived G2b: long-lived (all)
P (TeV)Mm
(TeV)N5 Cgrav
G1a 90 500 1 1.0
G1b 90 500 1 103
G2a 30 250 3 1.0
G2b 30 250 3 5x103
* Hinchliffe & Paige, Phys.Rev. D60 (1999) 095002; hep-ph/9812233
tan: 5.0; s()=+
~
~ ~ ~
~
~
LHC Physics 79P. Sphicas/ISHEP2003
SUSY parameters: GMSBSUSY parameters: GMSB
Point/Lumi (TeV) Mm (TeV) (tan N5
G1a @10fb-1 90±1.8 500±150 ±1.5 1±0.012
G1a @100fb-1 90±0.6 500±80 ±0.3 1±0.008
G1b @10fb-1 90±0.9(N5)+1.9
–1.3
G1b @100fb-1 90±8.1<7x105
(95%CL)+1.9 –1.3
G2a @10fb-1 30±0.4 250±44 ±0.7 3±0.036
G2b @10fb-1 30±0.18 250±25 ±0.21 3±0.014
LHC Physics 80P. Sphicas/ISHEP2003
8-fold (DAQ) way8-fold (DAQ) way
The DAQ system consists of two parts:- The front end electronics readout and the data link to surface-The DAQ core implemented as 8 DAQ slices each processing a fraction of the trigger rate
1
Detector Frontend
Filter Farm Network (64xn)
Readout Units
Builder Units
Event Manager
Level 1 Trigger
Controls CS
Builder Networks (64x64)
FED DAQ links 8x8 Builder
Filter Sub-farms
RU1
FU
64
BU1
64
512
'Front' view'Front' view
RU
BU
FU
FFN
EVM BDN
Level 1 Trigger
1
8
8x8 Little Builder
'Side' View'Side' View
1/8th DAQ slice
x 8
Data to surface: Average event size 1 Mbyte No. FED s-link64 ports > 512 DAQ links (2.5 Gb/s) 512+512 Event fragment size 2 kB Little builders (8x8) 64+64
1/8th DAQ slice: Lv-1 maximum trigger rate 12.5 kHz Builder network (64x64) .125 Terabit/s Event fragment size 16 kB Readout/Builder systems 64 Event filter power .5 TeraFlop Event flow control 105 Mssg/s Local mass storage 5 TByte
LHC Physics 81P. Sphicas/ISHEP2003
Regional reconstructionRegional reconstruction
Global • process (e.g. DIGI to RHITs) each detector fully• then link detectors• then make physics objects
14
Detector
ECAL
Pixel L_1
Si L_1
Pixel L_2
HCAL
Detector
ECAL
Pixel L_1
Si L_1
Pixel L_2
HCAL
Regional• process (e.g. DIGI to RHITs) each detector on a "need" basis• link detectors as one goes along• physics objects: same
LHC Physics 82P. Sphicas/ISHEP2003
Physics PicturePhysics Picture Example: inclusive electron trigger from Lvl-1
Step 1: fetch calo (& muon data) Apply Lvl-1 verification; sharper threshold Apply 0 rejection (based on crystals only) Apply isolation
Accept (say) 10-20% of the events Draw road inside tracker (this road would contain all hits from the
electron track if this is indeed an electron) Fetch all tracker modules that have geometrical boundaries
inside the road Find charged particle track
From CDF: track gives factor ~50; but factor 5 above, so this is factor 10 now. If event passes, read in rest of the tracker
Full selection: a set of successive approximations. Difference between “online”/“offline” selections:
Calibration & Steering of the code