P. Sphicas/ISHEP2003LHC Physics1 (Forward Look at) Physics at the LHC Outline n The LHC quick introduction/reminder n The detectors n Higgs physics in the SM and the MSSM n Supersymmetry: u Sparticles (squarks/gluinos/gauginos) u Precision measurements n Other (possible) new physics n TeV-scale gravity n Current status n Summary Paris Sphicas CERN and Univ. of Athens International School on High Energy Physics Crete, October 2003 P. Sphicas/ISHEP2003 Supersymmetry Sparticles P. Sphicas/ISHEP2003LHC Physics3 SUSY n Huge number of theoretical models u Very complex analysis; MSSM-124 u Very hard work to study particular scenario l assuming it is available in an event generator u To reduce complexity we have to choose some reasonable, typical models; use a theory of dynamical SYSY breaking l mSUGRA l GMSB l AMSB (studied in less detail) u Model determines full phenomenology (masses, decays, signals) P. Sphicas/ISHEP2003LHC Physics4 SUGRA n Five parameters u All scalar masses same (m 0 ) at GUT scale u All gaugino masses same (m 1/2 ) at GUT scale tan and sign( ) u All tri-linear Higgs-sfermion-sfermion couplings common value A 0 (at GUT scale) n Full particle table predictable u 26 RGEs solved iteratively u Branches: R parity (non)conservation u Extensions: relax GUT assumptions (add parameters) P. Sphicas/ISHEP2003LHC Physics5 Sparticles in SUGRA Contours of fixed g/q and / mass ~~ ~ ~ P. Sphicas/ISHEP2003LHC Physics6 LHC n Simplest SUSY u A SUSY factory Gauginos produced in their decay; example: q L 2 0 q L ~ ~ M=500 GeV P. Sphicas/ISHEP2003LHC Physics7 SUSY decays (I) Squarks & gluinos produced together with high u Gauginos produced in their decays; examples: q L 2 0 q L (SUGRA P5) q g q 2 0 qq (GMSB G1a) Two generic options with 0 : (1) 2 0 1 0 h (~ dominates if allowed) (2) 2 0 or 2 0 + u Charginos more difficult Decay has or light q jet u Options: l Look for higgs (to bb) l Isolated (multi)-leptons ~ ~ _ ~ ~ ~ P. Sphicas/ISHEP2003LHC Physics8 SUSY decays (II): rich cascades Heavy gluino branching ratio chart Heavy gluino branching ratio chart Large amount of Missing E T 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 ~ P. Sphicas/ISHEP2003LHC Physics9 SUSY decays (III): characteristics P. Sphicas/ISHEP2003LHC Physics10 Spectacular signatures expected Full simulation in CMS detector yet with 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) P. Sphicas/ISHEP2003LHC Physics11 SUSY mass scale n Events with 4jets + E T miss u Clean: S/B~10 at high M eff Establish SUSY scale ( 20%) Effective mass tracks SUSY scale well M eff (GeV/c 2 ) M SUSY (GeV/c 2 ) P. Sphicas/ISHEP2003LHC Physics12 SUGRA: the (original) five LHC points n Defined by LHCC in 1996 u Most of them excluded by now l Easy to bring them back u Points 1,3,5: light Higgses l LEP-excluded (3; less for 1,5) Restore with larger tan u Points 1&2: l Squark/gluinos 1TeV u Point 4: at limit of SB Small , large mixing l Heavy squarks u Point 5: cosmology-motivated l Small m 0 light sleptons increase annihilation of reduce CDM P. Sphicas/ISHEP2003LHC Physics13 Experimentally: spectacular signatures Prototype: 2 0 u Straightforward: dileptons + E T miss u Example from P3 l SM even smaller with bs l Also works at other points l But additional SM (e.g. Z 0 ) M measurement easy l Position of edge; accurate u Point excluded, but main point (dilepton-edge) still valid at other points ~~ M( + - ) (GeV/c 2 ) Events/(2 GeV/c 2 ) P. Sphicas/ISHEP2003LHC Physics14 other points n Multi-observations Main peak from 2 0 Measure m as before Also peak from Z 0 through 2 0 1 0 Z 0 l Due to heavier gauginos l P4 at edge of SB small 2 (a) and 0 are light (b) strong mixing between gauginos and Higgsinos u At P4 large Branching fractions to Z decays: e.g. B( 3 1.2 Z 0 )1/3; size of peak/P T (Z) info on masses and mixing of heavier gauginos (model-dependent) ~ ~ ~ ~ ~ ~ ~ M( + - ) (GeV/c 2 ) Events/(4 GeV/c 2 ) P. Sphicas/ISHEP2003LHC Physics15 SUGRA reach n Using all signatures tan =2;A 0 =0;sign( )= u But look at entire m 0 -m 1/2 plane u Example signature: l N (isolated) leptons + 2 jets + E T miss 5 ( =significance) contours n Essentially reach is ~2 (1) TeV/c 2 for the m 0 (m 1/2 ) plane CMS 100 fb 1 P. Sphicas/ISHEP2003LHC Physics16 Varying tan modes eventually become important At tan >>1 only 2-body 2 0 decays (may be): 2 0 1 0 Visible e excess over SM; for dilepton edge: need mass ~ ~~ ~ P. Sphicas/ISHEP2003LHC Physics17 The other scenario: 2 0 1 0 h n Followed by h bb: h discovery at LHC u E.g. at Point 1, 20% of SUSY events have h bb l But squarks/gluinos heavy (low cross sections) u b-jets are hard and central u Expect large peak in (b- tagged) di-jet mass distribution u Resolution driven by jet energy measurement u Largest background is other SUSY events! P. Sphicas/ISHEP2003LHC Physics18 Building on the h In analogy with adding jets to 2 0 u Select mass window (e.g. 50 GeV) around h u Combine with two highest E T jets; plot shows min. mass u Again, use kinematic limits l Case shown: max 550 GeV/c 2 u Beyond this: l Model dependence P. Sphicas/ISHEP2003LHC Physics19 Observability of decays into h Examples from CMS (tan =2&10) P. Sphicas/ISHEP2003LHC Physics20 n New set of benchmarks currently in use Account for LEP, b s ,g 2 and cosmology u Example: BDEGMOPW ( Battaglia et al, hep-ph/ ) u Recent: Snowmass points & slopes; working on updates Overall reach Benchmark Point # sparticles found Squarks Sleptons Charginos/neutralinos Higgses Gluino P. Sphicas/ISHEP2003LHC Physics21 SUSY parameters; SUGRA Point/Lumim 0 (GeV)m 1/2 (TeV) tan s 10040082.000.08ok 1004008102ok 502002102ok 430030.1ok Essentially no information on A 0 (A heavy evolve to fixed point independent A 0 ) P. Sphicas/ISHEP2003LHC Physics22 R P violation Non-conservation of leads to 3 new groups of terms (45 terms in total) in SUSY superpotential : R p = (-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 E T jet (HLT) > 30 GeV more than in t t _ P. Sphicas/ISHEP2003LHC Physics23 GMSB: NLSP and 1 0 lifetime If NLSP= 1, use TOF ( ~1ns) (good for high lifetimes) n Detecting the 1 0 G decay u Off-pointing photons + 1 0 decays in muon chambers ~ ~ P. Sphicas/ISHEP2003 SUSY: precision measurements P. Sphicas/ISHEP2003LHC Physics25 n Example: G1a; same dilepton edge u Decay observed: 2 0 1 0 G + u Selection is simple: l M eff >400 GeV l E T miss >0.1M eff l Demand same-flavor leptons Form e + e + + e n G2b: very similar to SUGRA 1 0 is long-lived, escapes u Decay observed: 2 0 u M eff >1 TeV; rest of selection as in G1a GMSB observation G1a ~ ~ ~ G1b ~ ~ ~ ~ P. Sphicas/ISHEP2003LHC Physics26 SUSY parameter measurements (G1a) n G1a: endpoint in M( ) 3 parameters u 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 l Plot lepton-photon mass, two more structures: min(M ) M P. Sphicas/ISHEP2003LHC Physics27 SUSY mass measurements (G1a) n Measurement of edge positions: very accurate Worse resolution on linear fit (e.g. min(M( )) l Low luminosity: 0.5 GeV; High lumi: 0.2 GeV (syst). One can extract masses of 2 0, 1 0, R Model-independent (except for decay, rate and interpretation of slepton mass as mass of R ) n Next step: reconstruct G momentum Motivation: can then build on 2 0 to reconstruct M q and M g 0C fit to 2 0 G + (with M G =0) Momentum to 4-fold ambiguity l Use evts with 4 leptons + 2 photons E T miss fit to resolve solns: min( 2 ): ~ ~ ~ ~ ~ ~ ~~ P. Sphicas/ISHEP2003LHC Physics28 G1a: masses of squarks and gluinos (I) Decay sought: q gq 2 0 qqq u Select evts with 4 jets (P T >75) Combine each fully-reconstructed 2 0 with 2 and 3 jets u This yields peaks at gluino and squark mass (direct) l Peak position not a function of jet cut ~ ~ ~ ~ P. Sphicas/ISHEP2003LHC Physics29 G1a: masses of squarks and gluinos (II) n Mass distributions can be sharpened Use correlations in M( jj) vs M( jjj) u Statistical errors small l Expect syst. dominance (jet energy scale) 800>(M W ) 2 ; But with SUSY M W 2 ~( / )|M SP M P | 2 l The pro-LHC argument: correction small M SP ~1TeV l 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) n SUSY does not answer why G F ~(M W ) -2 >>(M PL ) -2 ~G N u But it (at least) allows it P. Sphicas/ISHEP2003LHC Physics39 TeV-scale gravity n The idea of our times: that the scale of gravity is actually not given by M PL but by M W u Strings live in >4 dimensions. Compactification 4D SM. M PL-4 related to M PL-(4+d) via volume of xtra dimensions: l M PL-4 2 ~ V d M PL-(4+d) 2+d u Conventional compactification: very small curled up dims, M PL-4 ~M PL-(4+d) l V d ~ (M PL-4 ) d u Alternative: volume is large; large enough that V d >>(M PL-(4+d) ) d l Then M PL-(4+d) can be ~ TeV (!) our Planck mass at log( )~19: an artifact of the extrapolation P. Sphicas/ISHEP2003LHC Physics40 Getting M PL-4 ~1TeV n Can be, if V d is large; this can be done in two ways: u By hand: large extra dimensions (Arkani-Hamed,Dimopoulos,Dvali) l Size of xtra dimensions from ~mm for d=2 to ~fm for d=6 l But gauge interactions tested to ~100 GeV Confine SM to propagate on a brane (thanks to string theory) l Rich phenomenology u Via a warp factor (Randall-Sundrum) ds 2 = g dx dx +g mn (y)dy m dy n (x: SM coordinates; y: d xtra ones) l Generalize: dependence on location in xtra dimension ds 2 = e 2A(y) g dx dx +g mn (y)dy m dy n Large exp(A(y)) also results in large V d 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 P. Sphicas/ISHEP2003LHC Physics41 Extra (large) space-time dimensions n Different models, different signatures: Channels with missing E T : E T miss +(jet/ ) (back-to-back) u Direct reconstruction of KK modes l Essentially a W, Z search u Warped extra dimensions (graviton excitations) Giudice, Ratazzi, Wells (hep-ph/ ) Hewett (hep-ph/ ) P. Sphicas/ISHEP2003LHC Physics42 Extra dimensions (I): E T miss +Jet n Issue: signal & bkg topologies same; must know shape of bkg vs e.g. E T miss u Bkg: jet+W/Z; Z ; W . Bkg normalized through jet+Z, Z ee and Z events E T miss M D =5TeV M D =7TeV 5 Also E T miss + ; M D reach smaller P. Sphicas/ISHEP2003LHC Physics43 KK resonances+angular analysis n If graviton excitations present, essentially a Z search. u Added bonus: spin-2 (instead of spin-1 for Z) l Case shown*: G e + 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 P. Sphicas/ISHEP2003LHC Physics44 En passant n TeV-scale gravity is attracting a lot of interest/work u Much is recent, even more is evolving u Turning to new issues, like deciding whether a new dilepton resonance is a Z or a KK excitation of a gauge boson l 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 u Example: radion phenomenology l 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 u Stay tuned, for this is an exciting area P. Sphicas/ISHEP2003LHC Physics45 Black Holes at the LHC (?) (I) n Always within context of TeV-scale gravity u Semi-classical argument: two partons approaching with impact parameter < Schwarzschild radius, R S black hole l R S ~ 1/M P (M BH /M P ) (1/d+1) (Myers & Perry; Ann. Phys 172, 304 (1996) From dimensions: (M BH )~ R S 2 ; M P ~1TeV ~400 pb (!!!) Due to absence of small coupling like u LHC, if above threshold, will be a Black Hole Factory: l At minimum mass of 5 TeV: 1Hz production rate Dimopoulos & Landsberg hep-ph/ Assumptions: M BH >>M P ; in order to avoid true quantum gravity effects clearly not the case at the LHC so caution Giddings & Thomas hep-ph/ P. Sphicas/ISHEP2003LHC Physics46 Black Holes at the LHC (II) n Decay would be spectacular u Determined by Hawking temperature, T H 1/R S ~M P (M P /M BH ) (1/n+1) Note: wavelength of Hawking T H (2 /T H )>R S BH a point radiator emitting s-waves u Thermal decay, high mass, large number of decay products l 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 M BH ~M P. Then? Few quanta with E~M P ?) More generally: transplackian physics; see: Giudice, Ratazzi&Wells, hep-ph P. Sphicas/ISHEP2003 Beyond the LHC LHC++ P. Sphicas/ISHEP2003LHC Physics48 Beyond LHC; LHC++? n Clearly, a Linear Collider is a complementary machine to the LHC u Will narrow in on much of what the LHC cannot probe u Still a lot to do; e.g. see (and join/work!) LHC-LC study group n As for LHC, a very preliminary investigation of u LHC at cm -2 s -1 ; LHC at 25 TeV; LHC with both upgrades u First look at effect of these upgrades l Triple Gauge Couplings l Higgs rare decays; self-couplings; l Extra large dimensions l New resonances (Z) l SUSY l Strong VV scattering u Clearly, energy is better than luminosity l Detector status at needs careful evaluation P. Sphicas/ISHEP2003LHC Physics49 Possible LHC upgrades P. Sphicas/ISHEP2003LHC Physics50 LHC vs SLHC P. Sphicas/ISHEP2003LHC Physics51 Life at cm -2 s -1 P. Sphicas/ISHEP2003LHC Physics52 Implications for detectors n Tracking P. Sphicas/ISHEP2003LHC Physics53 Implications for Trigger P. Sphicas/ISHEP2003LHC Physics54 Expected Performance P. Sphicas/ISHEP2003LHC Physics55 Life at 25 TeV n Charged particle spectra P. Sphicas/ISHEP2003LHC Physics56 Higgs at SLHC P. Sphicas/ISHEP2003LHC Physics57 Supersymmetry LHC++ n mSUGRA scenario u Assume R P conservation u Generic E T miss +Jets u Cuts are optimized to get best S 2 SUSY /(S SUSY +B SM ) l In some cases 0-2 leptons could be better u Shown: reach given A 0 = 0; tan =10; >0 u For cm 2 s 1 probe squarks & gluinos up to ~ 4 TeV/c 2 u For cm 2 s 1 reach is ~ 3 TeV/c 2 P. Sphicas/ISHEP2003LHC Physics58 Strong WW/WZ scattering Golden modes considered (leptonic decays; e/ only) u Numerous channels (WW, WZ, ZZ). Worst-case (signal vs backgrounds) channel is WZ u Only L=10 34 cm 2 s 1 considered because analysis requires: l forward tagging jets and l central jet vetoes large effect from pileup at L=10 35 cm 2 s 1 n Like-sign WW & WZ: luminosity needed for 5 observation P. Sphicas/ISHEP2003LHC Physics59 Triple Gauge LHC++ Z kZkZ Z Machine Energy/Lum k Z x10 -3 Z x10 -3 NLC 0.5 TeV 500 fb LHC 14 TeV 100 fb LHC 14 TeV 1000 fb LHC 28 TeV 1000 fb P. Sphicas/ISHEP2003LHC Physics60 Extra (large) LHC++ n Signatures: the same Bonus: can extract M D and from (28 TeV) / (14 TeV) (since ~M D ( +2) ) u Topology used here: Jet+missing E T G q q g P. Sphicas/ISHEP2003LHC Physics61 Z' reach in LHC++ Only Z' considered M(Z')=8 TeV/c 2 signal vs Drell-Yan background Example: with Standard Model Br Reach in M(Z') is a function of Br(Z' ) P. Sphicas/ISHEP2003LHC Physics62 (Grand) Summary n Symmetry Breaking in the SM (and beyond!) still not really understood u Higgs missing; LHC (and ATLAS/CMS) designed to find it n Physics at the LHC will be extremely rich u SM Higgs (if there) in the pocket l Turning to measurements of properties (couplings, etc.) u Supersymmetry (if there) ditto l Can perform numerous accurate measurements u Large com energy: new thresholds l TeV-scale gravity? Large extra dimensions? Black Hole production? The end of small-distance physics? l And of course, compositeness, new bosons, excited quarks l There might be a few physics channels that could benefit from more luminosity LHC++? n We just need to build the machine and the experiments P. Sphicas/ISHEP2003 Backups LHC Physics64 Physics: planning vs reality P. Sphicas/ISHEP2003LHC Physics65 LHC status P. Sphicas/ISHEP2003LHC Physics66 SUGRA spectroscopy n Basic assumption: mass universality u Scalar masses: m 0 ; u gaugino masses: m 1/2 ; Higgs masses: (m 2 ) 1/2 n RGE: run masses down to EWK scale u M(squark): large Increase (due to 3 ) u M(slepton): small increase (due to 1, 2 ) u Gauginos: gluino is fast-rising; B-ino, W-ino mass decreases u Mixing leads to charginos (2) and neutralinos (4) Higgs: strong top coupling drives ; Symmetry Breaking mechanism arises naturally in mSUGRA(!) P. Sphicas/ISHEP2003LHC Physics67 SM Higgs properties IV: couplings n At high masses, ratio of HWW to HZZ (2:3) u Straightforward; top decay very difficult n At low masses (i.e. below ZZ threshold) more information P. Sphicas/ISHEP2003LHC Physics68 Status: summary n Some delays u Civil engineering etc n Startup: u Currently defined as 2x10 33 cm 2 s 1 in August 2006 u Expect: l 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) n Later: push to higher luminosity n Now turning to computing (resources etc.) P. Sphicas/ISHEP2003LHC Physics69 MSSM Higgses: expected LEP reach n Taking 208 GeV and actual luminosity recorded M(h) tan No mixing Max mixing M(A) tan P. Sphicas/ISHEP2003LHC Physics70 Extra dimensions (II): E T miss +photon n Rates much lower than for jet case u Channel could be a confirmation one Bkgs: +Z, Z & +W, W ; calibrated to Z ee (Z in Bkg)/(Z in ,ee) ~ 6 5 P. Sphicas/ISHEP2003LHC Physics71 Extra (large) dimensions n Different models, different signatures: Channels with missing E T : E T miss +(jet/ ) (back-to-back) l Results from theory papers based on similar signatures (e.g. gravitino searches); instrumental bkg: same signature u Direct reconstruction of KK modes l Essentially a W, Z search Giudice, Ratazzi, Wells (hep-ph/ ) P. Sphicas/ISHEP2003LHC Physics72 Summary n SUSY (if there) will be seen u It will be very difficult to not see SUSY if todays natural parts of SUSY space are natural indeed u Can determine parameters over fairly large part of SUSY space l Can perform a few precise measurements n Large com energy: new thresholds Compositeness, new bosons, excited quarks, etc; ~ 40 TeV n Large extra dimensions Can see them for M D up to ~ 5-10 TeV and =2-4 P. Sphicas/ISHEP2003LHC Physics73 Extra dimensions (III): Dileptons n Indirect signal: Drell-Yan u Leptons very clean; composite- ness-like signature; forward- backward asymmetry as well Also production Hewett (hep-ph/ ) P. Sphicas/ISHEP2003LHC Physics74 Determining SUSY parameters n From the edges of the spectra P5: q L q 2 0 q q + u ATLAS example: l 2 isol, OS leptons+4jets+E T miss l Combine leptons with 2 harder jets l Similarly, minimum at 270 GeV/c 2 l Both min & max visible Example shown: e subtracted ~ ~ ~ M( + q) (GeV/c 2 ) P. Sphicas/ISHEP2003LHC Physics75 Distinguishing 2 & 3-body decays n Two scenarios can be disentangled directly u From asymmetry of two leptons: In analogy with decays P. Sphicas/ISHEP2003LHC Physics76 New at LHC: amount of online selection P. Sphicas/ISHEP2003LHC Physics77 GMSB n Model assumes SUSY broken at scale F 1/2 in sector containing non-SM (heavy) particles u This sector couples to SM via messengers of mass M u Loops involving messengers mass to s-partners l Advantage of model; mass from gauge interactions no FCNC (which can cause problems in SUGRA) n Phenomenology: lightest SP is gravitino (G) u SUGRA: M(G)~O(1)TeV, phenomenologically irrelevant u GMSB: NSLP decays to G; unstable NLSP can be charged Lifetime of NLSP free: O( m) < c < O(km) u Neutral NLSP: lightest combination of higgsinos and gauginos behaves like SUGRA LSP (except for its decay) Charged NLSP: R ; low tan : degenerate e R, R, R ; high tan : R is lightest slepton, others decay to it ~ ~ ~ ~ ~ ~ ~ ~ P. Sphicas/ISHEP2003LHC Physics78 GMSB parameters SUSY breaking scale: =F/M u N 5 : # messenger fields tan (ratio of Higgs vevs) s( ) (| | fixed from M(Z)) u C grav (G mass scale factor) NLSP ~ (C grav ) 2 n GMSB points* G1: NLSP is 1 0 G1a: c is short (1.2mm) G1b: c is long (1km) G2: NLSP is G2a: e R, R, 1 short-lived l G2b: long-lived (all) * Hinchliffe & Paige, Phys.Rev. D60 (1999) ; hep-ph/ tan : 5.0; s( )=+ ~ ~ ~ ~ ~ ~ P. Sphicas/ISHEP2003LHC Physics79 SUSY parameters: GMSB Point/Lumi (TeV) M m (TeV) (tan N5N 1.85001501.51 0.6500800.31 0.9( N 5 ) +1.9 8.1