(forward look at) physics at the lhc

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


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)


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)


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


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


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

~

–

~ _~ ~

~


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

~


SUSY decays (III): characteristicsSUSY decays (III): characteristics


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)


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 )


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 +


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 )


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 )


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


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

~~ ~ ~


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!

–


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


Observability of decays into hObservability of decays into h Examples from CMS (tan=2&10)


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


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)


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 _


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

~~


SUSY: precision measurementsSUSY: precision measurements


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

~ ~

~

~


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


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


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…

~ ~ ~ –

~


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


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


Cosmology, CDM and LHCCosmology, CDM and LHC


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


Other new Physics Other new Physics (Or WBSM)(Or WBSM)


Other resonances/signatures (I)Other resonances/signatures (I) New vector bosons


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


Excited quarksExcited quarks Search for q*q


TeV-scale gravityTeV-scale gravity


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


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


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


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)


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


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


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


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


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


Beyond the LHCBeyond the LHC

LHC++


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


Possible LHC upgradesPossible LHC upgrades


LHC vs SLHCLHC vs SLHC


Life at 10Life at 103535 cm cm-2-2ss-1-1


Implications for detectorsImplications for detectors Tracking


Implications for TriggerImplications for Trigger


Expected PerformanceExpected Performance


Life at 25 TeVLife at 25 TeV Charged particle spectra


Higgs at SLHCHiggs at SLHC


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


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


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


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

qq

g


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')


(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


BackupsBackups


Physics: planning vs realityPhysics: planning vs reality


LHC statusLHC status


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(!)


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


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.)


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


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


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)


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


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)


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)


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


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


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

~~

~

~ ~ ~ ~~


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()=+

~

~ ~ ~

~

~


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


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


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


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

(forward look at) physics at the lhc

Documents