PoS(HEP2005)402 http://pos.sissa.it/ ce. rd Model are given. Finally the son properties and Standard-Model l Linear Collider (ILC) is summa- rds it are described. cs ive Commons Attribution-NonCommercial-ShareAlike Licen ∗ [email protected] concepts for an ultra-high-precision detector and R&D towa processes as well as new physics scenarios beyond the Standa The major physics motivation to construct the Internationa rized. The prospects for precision measurements of Higgs bo Speaker. ∗ Copyright owned by the author(s) under the terms of the Creat c July 21st - 27th 2005 Lisboa, Portugal International Europhysics Conference on High Energy Physi

Klaus Desch Albert-Ludwigs-Universität Freiburg, Freiburg, Germany E-mail: International Linear Collider: Physics and Detectors PoS(HEP2005)402 Klaus Desch , it is very likely that an impressive way. Through ascale? What is the origin ll be addressed if we explore ified extra space dimensions, le extensions [2]. Furthermore e Planck scale? Are there hints operties of the new particles in he Higgs mechanism at work or ctron- colliders is mainly ted by colliders and lepton ot have been possible without the erascale is fully exploited. rgy phenomena. Most notably the olliders. Only the latter allowed for st prominent among these questions to a precise knowledge of the initial ics will need additional experimental eady be ruled out or at least severely s the future experimental program for will start. The discoveries will set the view of particle physics which enables of dark matter and questions related to ental fermions and gauge bosons at the the percent-level is necessary which in s of the Higgs boson to below 200 GeV n and lepton colliders has already in the ng of the underlying physics. It has been le becomes an increasingly important tool 2 state; has Nature chosen a different solution? of the large hierarchy betweentowards the a electro-weak unification scale of and all th known forces? whose consequence become visible at the Terascale? The reason for the superior precision of measurements at ele These measurements confirm the predictions of the SM in a very With the start of the LHC at CERN in 2007 Many of the most burning questions of microscopic physics wi 1. Point-like nature of the colliding particles which leads 2. Tunable collision energy, allowing for threshold scans; 1. What is the origin of electro-weak symmetry breaking? Is t 2. Are there new symmetry laws which become visible at the Ter 3. What is the structure of our space-time? Are there compact due to the following reasons: quantum level analyses, it was possible toat constrain the the mas 95% confidence levelmany within new the physics SM scenarios and acting many atconstrained by the of these Terascale its precision could possib measurements. alr era of ground-breaking discoveries inscene the for Terascale their regime further exploration andshown for that the understandi the LHCmany can cases perform [1]. initial However a measurements fullefforts. of exploration of The the Terascale complementarity phys pr of thepast possibilities proven at to hadro beexperimental essential verification for of the the understanding Standardprecise of Model measurements high (SM) of the ene would LEP n andcomprehensive tests SLC of -positron the c coupling structurelevel of the of fundam quantum corrections. Tomany achieve cases this, is precision only at possible atus lepton to colliders. make Our solid current predictions forthe Terascale LHC physics and and beyond shape was onlycolliders. possible through the synergy crea International Linear Collider: Physics and Detectors 1. Challenges at the TeV-Scale and the ILC the TeV energy range, sometimes called theare: Terascale. The mo Furthermore, experimental particle physics at the Terasca to answer questions of cosmology. Inthe particular, Baryon the asymmetry nature in the universe can be addressed if the T PoS(HEP2005)402 ser Klaus Desch (Giga-Z) and the . The microscopic Z M = s √ telescopic ctro-weakly interacting initial le physicists has emerged that lassification can be done in the grounds; the ILC for the most important and d in great detail and documented cility for particle physics [3]. In s is that independent of the what iving at a detailed technical design most often crucial measurements to ameters for the machine are [5] d analysis of the helicity structure of unning at en deep into the multi-TeV region, far ccelerating structures was selected for used to look for quantum level effects ays, production modes, cross sections, atus of the development for ILC detec- inematically accessible at ILC energies Collider (ILC). For the ILC, the Global g of the underlying physics. The precise n the fact that precise measurements of ready successfully exploited at LEP and of-mass energy of up to 500 GeV in a first microscopic per year. 500 GeV, 1 3 in the first four years, − ≤ 1 s − √ ≤ Z M collisions through Compton backscattering of an intense la γ e and γγ the processes and sometimes significant suppression of back state; electron-positron collisions at upgradability to about 1 TeV with 500 fb electron and positron polarisation, integrated luminosity of at least 500 fb The physics capabilities at the ILC are two-fold, In the past years, the physics case for the ILC has been studie In the following I will discuss the expected capabilities of In the past years, a broad world-wide consensus among partic • • • • 3. Possibility to polarize both beams, allowing for detaile 4. Moderate backgrounds from SM processes due to the only ele 5. Moderate machine backgrounds. possibility to provide in numerous reports [6].the LHC The will (or general will outcome not)perform. of discover, the These these ILC will significantly has studie enhance important the and tasks understandin of the ILC of coursefollowing depend way: on the LHC findings. A simple c physics scenarios. Then I will discusstors. the challenges and st 2. Physics Scenarios capability lies in the fact thatcan any be new studied particles in which are great k detail,and i.e. coupling its structure. quantum numbers, The dec telescopic capability relies o above the direct kinematical reach of the ILC. either SM or new particle differential cross sections can be SLC provides sensitivity to new particles and phenomena oft beam. arising from virtual particles in loops. This technique, al International Linear Collider: Physics and Detectors a linear electron-positron collider operating at a centre- 2004 the accelerator technology based onthe superconducting world-wide a project now called theDesign International Effort Linear (GDE) [4] has startedof in the 2005 machine with and the the aim detectors of in arr 2008/09. The baseline par phase and upgradable to 1000 GeV be the next major collider fa Further options for the machine include a high-luminosity r PoS(HEP2005)402 , Z ay ith an above 2m Klaus Desch H Z. Z bosons can 0 H . For m → Z [9]. The measurement in Higgs-strahlung can − [8]. The corresponding decays can be used. The 0 e data are inconsistent with 2m 1 PC + − that the LHC hasn’t missed J -weak radiative corrections − ddition, precision measure- oth Higgs boson production < τ kinematic reach of the ILC tial details. n order to get a hint of multi- os is one of the key tasks in + the production threshold was H τ an also be determined from the s in the context of Higgs Bosons, gs boson properties at a ILC is the nsion models, little Higgs models electro-weak measurements): the oson: → , allowing for a model-independent ns and decay angular distributions for m 0 is known, all other Higgs couplings on electro-weak measurements): the exploited to gain sensitivity to Higgs gainst the H ∗ ZZ ulated. Through a cut on the recoil mass, HZZ 160 GeV, a large variety of Higgs decay lung process, e g n inH → < 0 H 350 GeV for 500 fb . Once 4 = s HZZ g √ decays [7]. From energy-momentum conservation, the − µ + leptons is probed through angular correlations of their dec µ τ → . The total Higgs-strahlung cross-section can be measured w 120 GeV and = and Z H − e + e absolutely → -dependence of the Higgs-strahlung cross-section close to β ILC can verify that the Higgs mechanism is at work in all essen ILC can again verify the Higgs mechanism in most details. In a ments of SM processes will beare inconsistent important with to the find observed out Higgs why mass. electro (e.g. supersymmetric particles, new states frometc.): extra precise dime spectroscopy of the new states. anything and perform precise measurements ofTeV SM phenomena responsible processes for i EWSB and findSM out radiative why corrections. precision The precise measurement of Higgs boson decay branching rati The CP quantum number, like the spin, can be determined from b In the following I will briefly describe the main measurement The anchor of a model-independent precision analysis of Hig The measurements of differential production cross-sectio 1. If there is a light Higgs boson (consistent with precision 2. If there is a heavy Higgs boson (inconsistent with precisi 3. Either light or heavy Higgs bosons and new particles in the 4. No Higgs boson at LHC, no new states: the ILC has to make sure products. ILC Higgs physics. For a light Higgs boson with m be exploited. Furthermore, the transverse spin correlatio of the be selected in Z can be determined accuracy of 2.5% for m azimuthal correlations of the two Z bosonboson decay spin planes and can be CP [10]. and decay [11]. The angular distribution of the Z recoiling a exploited to determine theinvariant spin mass of of the the off-shell Higgs Z boson boson. in the The decay H spin c Higgs bosons can be selected independentmeasurement of of their the decay effective mode HZ coupling, invariant mass recoiling against the Z candidate can be calc International Linear Collider: Physics and Detectors measurement of the total cross-section for the Higgs-strah Strong EWSB, Supersymmetry, and Top . 2.1 Higgs Boson Precision Physics spin correlations between the two recoil mass spectrum is shown in Fig. 1. provide access to the discrete quantum numbers of the Higgs b PoS(HEP2005)402 1 − − → and W − . , + 1 e 0 − + Z W ¯ b decay, 0 b Z 10% for a → , Klaus Desch 0 ∼ − → 0 W + 120 GeV [8]. om Higgs decays. is be detectable in ieved. W = , − − H µ τ g ratio is . The shaded histogram m 0 + + , Z 1 τ µ , − → gg h a , 0 X at 800 GeV range from 6–14% e process only has a significant c¯c on is the ultimate proof of spon- at the LHC. In particular a mea- µµ 1 ,

here are two methods to measure ¯ − b → tained from a sample of 1 ab b ation of the SM bosons and fermions ] ukawa coupling is the process e resence of a vacuum expectation value. by missing energy from the Higgs de- Data Z H on plus 8-jet final states were studied. nto b te of Higgs decays. The second method ugh the comparison of the decay-mode- and gg are disentangled via the excellent yond 500 GeV. For the H = 120 GeV , 350 GeV, 500 fb GeV [ H c¯c = , m s ¯ b √ 120 GeV. A measurement of the Yukawa 5 = H Recoil Mass events ( 0 Z 0 ¯ qq¯canl havebq¯qq¯qchannels been analyzed. For the H H b → → − 100 120 140 160 observation down to a branching ratio of 1.5-2.0% with 500 fb t ¯ e 0

+

σ e 200 100 Number of Events / 1.5 GeV 1.5 / Events of Number 800 GeV for m = s and the t √ ¯ ν − , the top Yukawa coupling is not directly accessible fr ` t 200 GeV. ¯ 2m bq¯q 350 GeV, the achievable precision on the invisible branchin < b < H = → H s Recoil mass of events with two isolated consistent wit m t ¯ 350 GeV and Higgs masses between 120 and 160 GeV [13] can be ach √ < = The observation of a non-zero self-coupling of the Higgs bos Invisibly decaying Higgs bosons are difficult to be detected For m s t [12]. Due to the large masses of the final state particles, th ¯ further decay modes have been studied. The very rare decay H t √ 0 taneous symmetry breaking being responsible forsince mass it probes gener the shape of the Higgs potential and thus the p branching ratio of 5% and a 5 surement of the Higgs massthe is invisible almost Higgs branching impossible. ratio. At Theindependent first the Higgs proceeds ILC, production thro t rate with theexplicitely total requires visible a ra reconstructed Z-Bosoncay. accompanied At for 120 The only relevant tree level process to access the top quark Y both the t coupling with approximately 15% relative accuracy may be ob cross-section at center-of-mass energies significantly be H decay, the 2-like-sign lepton plusThe 6-jet expected uncertainties and on the the single top lept Yukawa coupling for 1a modes can be measured. The hadronic decays into b γγ WW-fusion events at Figure 1: International Linear Collider: Physics and Detectors at represents the contribution from capabilities of an ILC vertex detector. Besides the decays i PoS(HEP2005)402 e 120 etric = H 1 TeV from Klaus Desch = s [19]. n of 0.1 - 0.2 fb √ at 5 α from the SM. The error bars and 4 t way by the study of trilinear α de for longitudinally polarized lings is sufficient to discriminate 2 TeV unless new interactions set ]. In Fig. 3, the ratio of the decay improvements can be obtained if . nergy, the double Higgs-strahlung ble by LHC or ILC measurements. rences e.g. between a one-doublet es at higher energies was discussed 1 ed by an effective Lagrangian [20]. teraction (Technicolor) or delay the or ultimate jet energy resolution since ∼ of data at 500 GeV, a precision of 17 ams which lead to the same final state s rtic Higgs boson couplings out of which rameters An experimental analysis for m 1 esonances, e.g. Kaluza-Klein excitations rams) are exploited [17]. − √ Z cross-section can be achieved. The po- 0 H 0 H 6 ¯ → bq¯qcan be reconstructed, the signal rate becomes − ¯ bb e + violates unitarity at L is shown relative to its SM value as a function of the mass of th W L − for a broad scan of parameter points of the Minimal Supersymm W W A + → L W 140 GeV on the e W Z is most promising for observation, the small cross-sectio L 0 < → H W 0 H 0 can be significantly constrained up to masses of about 800 GeV m H A < → ¯ b to h b − e Deviation of the Higgs couplings in a two Higgs doublet model → + 0 The achievable percent-level precision on Higgs boson coup If no elementary Higgs boson exists, the scattering amplitu At the ILC these models can be analyzed in a model-independen however demands the highest possible luminosityonly and calls if f the most frequent six jet final state b between different models.model As like shown the in SM and Fig. two-doubletmodes 2, models h can distinct be diffe exploited [18 Figure 2: denote the achievable precision at the ILC [18]. International Linear Collider: Physics and Detectors Higgs boson self-coupling in general leads toonly triple and the qua former are accessible.process, e For 500 GeV center-of-mass e significant. The cross-section has been calculated in [14]. weak gauge bosons, heavy CP-odd Higgs mass m (MSSM) which are notIt can otherwise be distinguisha seen m 2.2 No elementary Higgs boson in. These new interactions mayunitarity either violation by involve a introduction new new weakly strong couplings in r and quartic gauge boson couplings.In Those Fig. 4 can (left), be the parameteriz sensitivity of the ILC to the coupling pa of gauge bosons(Higgsless models). GeV was presented [15] which concluded that with 1ab - 23 % for 120 tential of the WW-fusion channel forand higher compared Higgs boson to mass thekinematic possibilities differences at between the the LHC signal diagramwithout in involving and [16]. the diagr triple Higgs Further coupling (dilution diag PoS(HEP2005)402 boson 0 Z r coupling Klaus Desch for model points consistent A at the ILC, they can naturally esonance in Higgsless model [22]. cannot be directly produced, their ]. ouplings [21]. , behaving like a sequential are shown. The bounds correspond to 7 MSSM/SM within the as a function of m ) -propagator allows us to determine the vector-axial-vecto WW 2 γ ee WWZ π / → Z *16 4 h 68%c.l. ( α BR VV VV / ) ¯ b −1 b → h ( 90%c.l. Left: constraints on quartic gauge couplings [21]. Right: R s = 1TeV

BR L = 1000fb

5

*16 π If weakly coupled resonances can be produced kinematically α 2 Figure 4: from a Higgsless model is showninterference [22]. with Even the if SM- such resonances structure if the resonance mass is known e.g. from the LHC [23 Figure 3: International Linear Collider: Physics and Detectors vector-boson scattering and three vector boson production with direct SUSY signals at LHC and ILC [19]. mass limits of approximately 3 TeV for resonances with unit c be studied in great detail. In Fig. 4(right) such a resonance PoS(HEP2005)402 exchange Klaus Desch Z / γ is shown [24]. 0 1 ft) the measurable χ − µ 0 1 -channel ˜ χ s measurements of the su- + rst measurements of SUSY µ via ` e possibility of tunable centre- ¯ → ˜ ν the production cross-section for ` ticular background from W-pair an be suppressed by topological − ed in two different ways. First, in R ˜ ν ˜ µ , ast a large part of the color neutral (GeV) mined. anism of SUSY breaking and may − s j + ions for future high energy particle − R √ handed in the initial state. rum has a box shape. From the upper ˜ USY measurements. Both machines xtraction of the sum of the produced ` ˜ ch allows for deciphering the coupling µ SPS1a© + i ra can be used to extract simultaneously ˜ ` oduction processes (see Fig. 5). → → collisions for benchmark point SPS1a’. Right: − R e − − + L e e e + + e 8 Squarks Higgs Neutralinos Charginos Sleptons 200 300 400 500 600 700 800 900 1000 3 2

-1

1

(fb) 10 10 10 σ 10 exchange for the first generation. As an example, in Fig. 6(le ˜ χ Left: SUSY production cross sections in e -channel The precision SUSY analyses at the ILC greatly benefit from th The search for Supersymmetry (SUSY) and, should it be found, The LHC has a huge potential for SUSY discovery as well as for fi The masses of the color-neutral superpartners can be measur Sleptons are pair-produced in the reactions t of-mass energy and from the polarisablilty of bothstructure. beams whi For a large partsparticles are of visible the at SUSY the parameter ILC in space, a at variety le of different pr energy spectrum of the muons from the process Figure 5: particle properties. The ILCtogether is will an be ideal able toolopen to for a precision give window to important S GUT/Planck insight scale into physics. the mech International Linear Collider: Physics and Detectors 2.3 Supersymmetry perpartner properties are amongcolliders. the most important motivat Events can be selectedproduction with can negligible be SM efficiently background.SUSY suppressed backgrounds by In in choosing par this right- cuts. final Due state to are the scalar generally natureand small of lower the end-points, and smuons, the c the slepton energy and spect LSP masses can be deter and Muon energy spectrum in smuon pair production [26]. continuum production kinematic end-points of energy spect the involved masses. Second,various the processes measurement near of threshold the allowssuperpartner for shape masses. a of very precise e PoS(HEP2005)402 → 1 ˜ t →→ 1 either ˜ t 294 1 decays larized ˜ t 0 1 utralino 1 ˜ -channel ˜ ˜ χ t ν → s leptons in − − ` Klaus Desch → τ e + via 292 − may therefore + ` j 0 e e slepton is often ˜ ± 1 χ + rgino decays ac- → 1 0 e χ i ˜ τ 0 ˜ 2 final states, a mass χ ˜ , invisible χ ¤ 0 2 290 τ ˜ © χ the and → ’s and missing energy. ¨ 0 m τ § 2 LC, the light scalar top β ¡ − per point a precision of χ e boson or if kinematically ¦ ross-section with opposite < 1 , ght:Threshold scan [25]. + ¥ ˜ ± ˜ τ − e ν 288 GeV from a threshold scan. the rate will be sufficient to m W 1 − and 10 fb -jets, two corrections and final width correc- j ∓ es. As in the case of sleptons, the lues of tan ficant enhancement of b on energy and mass spectra as well reshold scan as shown in Fig. 6(right) 286 ˜ χ k, the decay chain ve decays into ¤ essible in the reaction £ ± i ¢ cesses for ¡ ˜ χ nd muon final states are produced with

decays according to → 2 1 3 0 collisions and for right smuon production. 3.5 2.5 1.5 0.5 − − e e + − e e 9 and − e + e . The final state consists of two -jets can be used to reconstruct the stop mass provided the ne missing energy signature. Topological cuts and the use of po 0 1 b ˜ χ either via an intermediate virtual or real + ν − 0 1 − τ ˜ χ boson or via a real slepton. In particular, if τ + ` ¯ b ν τ -channel selectron or sneutrino exchange. The lightest cha Z 0 1 t ± ˜ χ ` ν + → τ Left: Muon energy spectrum in smuon pair production [24]. Ri b ± 1 ˜ χ → has also been studied. From a measurement of the production c − 1 0 1 ˜ χ ˜ χ ¯ exchange and b Charginos and neutralinos are pair-produced Although squarks are often too heavy to be produced at a 1 TeV I Alternatively, the slepton masses can be extracted from a th ¯ c Figure 6: + 0 1 1 Z (100 MeV) can be achieved. With this precision higher-order ˜ ˜ χ / χ c and chargino masses areachieve known. a mass resolution With of a 2 GeV. luminosity For a of light scalar 1000 top fb quar O tions have to be taken into account [25]. b With measurements at five center-of-mass energies with only possible via a real slepton. The second lightest neutralino via a virtual or real beams can help to disentanglechargino and the neutralino contributing masses SUSY can process beas measured from from threshold the scans. lept precision In the of more a difficult few caseSignificantly GeV of better can exclusi precision be can achieved besufficient in achieved rate if the [26]. electron continuum a and 0.5 γ may occur. For large mixing in the stau sector and for large va quark may be lighter than the other squarks and therefore acc The energy spectrum of the International Linear Collider: Physics and Detectors for right selectron production both in much lighter than the other sleptons which can lead to a signi all lead to the same cording to the chargino and neutralino final states. The production pro PoS(HEP2005)402 , − R ↔ ˜ e R tate, , + R − L ˜ e e 1 1 − − → − Klaus Desch e + 1 e − 1 1 which is funda- 1000 fb 1000 fb − − ) 1 > > 0 − ˜ χ ˜ e 0 ctrons, 1 1 e ˜ from their SM partners. χ ( − at 500 GeV in a SPS1a g 1 2 1 W , − 1 ± 1 − ˜ , 750 GeV, , 750 GeV, χ 1 , 1TeV, 1000 fb 0 0 4 4 , 100 fb 1 ) Z − ˜ ˜ 0 ˜ χ χ 2 t e SPS1a scenario is summarized ring by of superpartner masses the mea- − ( ˜ 0 0 3 3 χ irectly from the production angle ) SUSY Yukawa couplings can be 1 ˜ ˜ → llider experiments, SPS 1a mSUGRA gle can be inferred [27]. 0 χ χ 2 1 n important role in deciphering the mbiguous way to scalars, i.e. h 500 fb − ˜ , , min χ − contribution. The forward-backward ± 2 0 0 n is more complicated for charginos 4 3 y in the production angle due to their wa coupling ˆ ˜ stributions in production and decay. m ˜ ˜ χ rices [29]. χ χ ings exist. These range from the mea- ms [30]. The t-channel contribution to 0 0 2 2 ˜ ˜ χ χ ymmetry provide sensitive observables in , , 2 ± , 1 0 1 ˜ χ ˜ χ distribution which can be reconstructed up to , spectra Z W ∓ 2 θ ˜ 10 χ 2 → → ± 1 can be disentangled from their different dependence -jet spectrum, ˜ 0 0 3 4 χ b ˜ ˜ − R χ χ ˜ e threshold scan, 10 fb threshold scan 20 fb + L ˜ e − − e e → − − e simulation energy spectrum, 500 GeV, 500 fb simulation energy spectrum, 400 GeV, 200 fb estimate threshold scan, 100 fb simulation energy spectra, 400 GeV, 200 fb estimate threshold scan, 60 fb estimate Comments simulation threshold scan , 100 fb estimate combination of all methods simulation threshold scan spectra spectra e − e collisions, due to the low background and the known initial s ] + e − , e − L + GeV ˜ 2 3 e e [ 0.2 1.2 0.2 0.5 0.3 1.1 1.2 0.55 0.05 0.05 + R 3 – 5 3 – 5 ˜ e m ∆ → . The four pair-production processes for left and right sele ] − L e , + R + ˜ e e GeV , [ 96.1 202.1 186.0 143.0 202.1 133.2 206.1 379.1 176.4 378.2 176.8 358.8 377.8 143.0 ↔ − L ˜ e m R , + L + L ˜ e Sparticle masses and their expected precisions in Linear Co e 0 0 0 0 L e R 4 1 2 3 ± ± 1 2 L R 1 2 1 ˜ ˜ ˜ ˜ ˜ ˜ ˜ ˜ ˜ ˜ ˜ t ˜ τ τ ν ˜ ˜ e e µ χ χ χ χ µ → χ χ The fundaments of SUSY rely on the superpartners’ spin diffe In SUSY,the chiral (anti-)fermions are associated in an una Besides the precise measurement of the largest possible set The achievable superpartner mass precision of the ILC for th and − e R , + − L ˜ of the cross-section to polarizedthe electron production and cross-sections positron is bea sensitive to the SUSY Yuka e e scenario [24]. various possibilities to extract quantumsurement numbers of and inclusive coupl rates to the measurement of angular di surement of quantum numbers, couplings,supersymmetric and model. mixings plays In a At the ILC, the spinsdistributions. of the The superpartners scalar cana leptons be twofold exhibit determined ambiguity a d in sin smuonand neutralinos pair-production. which The exhibit a situatio forward-backwardmixed asymmetr U(1) and SU(2) couplings andasymmetry the and additional in t-channel particular the left-rightorder polarization to as disentangle the chargino and neutralino mixing mat International Linear Collider: Physics and Detectors beam polarizations, a measurement of both mass and mixing an in Table 1 taken from [28]. Table 1: mentally related to the SM gaugedetermined couplings. to The a SU(2) and precision U(1 of 0.7% and 0.2%, respectively wit scenario (from [28]). PoS(HEP2005)402

Klaus Desch

mt

MArun

M3

ped to achieve this goal. As M2

rangian can then be extrapo- M1 atellite [36] strongly constrain partners at LHC and ILC will lobal fit to LHC and ILC observ- . Measurements of temperature

sed which includes higher-order

MSSM with 19 free parameters converging fit. The definition of MStL he full MSSM but assuming real

ns in the MSSM parameter space.

energy MSSM Lagrangian. At tree e noted that neither LHC nor ILC ersality of the soft SUSY breaking is currently being worked out in the MSuL predictions for the observables as a

lete set of SUSY observables at LHC

ne distinct patterns of unification and king [35]. ctor, e.g. the chargino sector is com- oss-sections, and branching ratios are

meters from data is no longer possible. MStR e depends on the full set of SUSY param- MSbR . However, with the anticipated precision

no theo.unc.

β MSuR tan Xb ,

µ Xt 11

,

2 MStauL M

Parameter

SPS1a' scenario MSeL

MStauR

MSeR

Xtau Mu

with theo. unc. tanBeta -0 0.1

0.4 0.3 0.2

-0.1 -0.2 -0.3 -0.4 Relative uncertainties and bias and uncertainties Relative Relative uncertainties of SUSY parameters obtained from a g The ultimate goal of measurements of the properties of super Two programs, SFITTER [31] and Fittino [32] have been develo The extracted parameters of the electro-weak scale MSSM Lag The SUSY LSP provides an excellent candidate for dark matter Figure 7: be the extraction of thelevel, complete the set of parameter parameters determination of canpletely the proceed determined low sector by by the se threeof parameters ILC measurements, higher order correctionsnot to negligible. masses, At cr loop-level in principle every observabl eters. An analytic procedure to extract the Lagrangian para International Linear Collider: Physics and Detectors Instead, a global fit of theand Lagrangian ILC parameters will to be the comp necessary. an example, a recenthas result been from chosen Fittino as iscouplings, the flavour explained theoretical diagonal here. basis. sfermionparameters mass A It matrices of is and the univ first derivedfunction two from of generations. t the parameters For thecorrections SPHENO the [33] wherever theoretical program they has been haveinput u been alone calculated. can constrain It thea should assumed scheme model to b enough extract to well-definedSupersymmetry parameters yield Parameter at a Analysis higher (SPA) project orders [34]. lated to high (GUT, Planck) scalesreconstruct (Fig. the 8 underlying in fundamental order theory to of determi SUSY brea 2.4 Connection to Cosmology: The Nature of Dark Matter ables [32]. fluctuations of the cosmic microwavethe background SUSY by the LSP WMAP properties s and therefore point to certain regio PoS(HEP2005)402 2 2 of H 1 M − decays mass is ˜ τ τ [GeV] Klaus Desch Q matter density ] which contributes sig- visible energy and the 2 τγ [GeV ˜ j 2 → M ˜ from [40]). τ e measured very precisely from el. It is therefore imperative to 0 ˜ χ y, from a scan with 100 fb c) rge missing energy. Two-photon ronic energy spectra for toed by the detection of very for- . Full bands: only experimental errors 0 precise measurement of the t. The statistical accuracy of the top ¯ cant energy induced by beam-beam- al control of the cross section. With t neration of CMB experiments, in par- ocess is small. The relic dark matter density g logarithm (NNLL) calculation being . This precision matches the anticipated ) → rs is the co-annihilation region in which 0 m 1 [GeV] ˜ − rrors are taken into account as a conservative χ ∆ e ( first generation scalar mass parameters and Q in SPS1a + m b) 1 2 H − region has been studied in [37, 38, 39] for various ) M 12 ˜ τ m as shown after detector simulation and cuts together ( ∆ 0 1 m ] 2 ˜ 5 GeV (Model Point D χ = mass and on − = τ ˜ τ m [GeV 0 1 m ∆ ˜ j 2 ˜ 100 MeV precision will be possible (Fig. 9 (left)) [42]. χ ∆ M + ∼ τ b) → 1 with ˜ τ t 1 ˜ m τ [GeV] the gaugino mass parameters, 3 GeV. The resulting precision on the prediction for the dark → Q ∼ − R a) e m + L ∆ e ] 1 − is small (typically below 10 GeV), the staus decay with small Running of m [GeV ∆ third generation scalar mass parameters and 1 − i At the ILC, the mass of the heaviest quark, the top quark, can b If The pair production of staus in the small- c) M a) ranges from 2 to 6%, depending on the estimate [32]. Of particular interest for experimental studies at collide are taken into account; dashed lines: today’s theoretical e the neutralino annihilation is enhanced by the t-channel pr and mass and decay width is possible to 34 and 42 MeV, respectivel a scan of the production threshold for the processdata e [41]. The largestan uncertainty appropriate comes mass from definition theavailable, theoretic and an extraction next-to-next-to-leadin of 2.5 Precision Measurement of the Top Quark Mass with the two-photon background for possible down to from the process International Linear Collider: Physics and Detectors nificantly only if the mass difference Figure 8: depends critically on this massticular difference. Planck, With the the next DM ge match density this can precision be at colliders. measured at the 2-3% lev signature is only abackground few is soft becoming charged severe tracksward unless accompanied scattered it by electrons. can la be Ininteractions efficiently the is ve deposited. very forward region signifi MSSM parameter sets. With appropriate cuts, detection and a precision of the Planck satellite of 2%. As an example the had PoS(HEP2005)402 in the A h m f for different Klaus Desch = 5 A β m = 2.0 GeV = 1.0 GeV = 0.1 GeV exp exp exp t t t [GeV] A m m m = 175 GeV, tan = 175 GeV, δ δ theory prediction for m δ t M since it is a fundamental SM as a function of ourable background conditions h resolution typically far superior l jet energy resolution is achieved m m taking collision data with the least particle. In particular, charged par- exp h udied detector designs. This concept nergy resolution. In order to achieve cle tracking and calorimetry is given. m out any hardware trigger allowing for t the energy or the momentum of each ∆ of beyond-SM physics. As an example ector designs which are currently devel- en the relatively low interaction rates, it escribed. Finally a short overview about subsystems. In particular the reconstruc- required resolutions to achieve the statis- gion for 150 200 250 300 350 400 450 500

120 130 115 125 135

h

[GeV] m -collision are fully reconstructed individually. If − 13 e cross section close to production threshold for different 352 + → 351 − e + 350 will be measured to 50 MeV precision, the top mass will be the H 349 m NNLL 348 s (GeV) _ on the prediction of the light Higgs boson mass as a function o t 347 m [43]. 346 t m 345 Left: NNLO calculation of e 344

0.4 0.2 0.0 1.4 1.2 1.0 0.8 0.6

t

R Q The particle flow concept is guided by the idea that the optima The enormous statistical power of the ILC machine and the fav A precise knowledge of the top quark mass is desirable a such, v 2 ongoing sub-system R&D for vertex detectors, charged parti 3.1 The Particle Flow Concept this can be achieved, the bestparticle possible species method can to be reconstruc chosenticle depending momenta on can the nature be of measured the from the tracking system with a tically possible resolution are challenging fortion most of of the hadronic final states requires an unprecedented jet e oped in international detector concept studies are briefly d should be matched by apossible precision introduction detector of which biases is and capablewill systematic of be errors. possible Giv to constructevent a filtering after data full acquisition reconstruction system of with the events. The this goal, the particle flow conceptwill has be been explained chosen in by the most next st section. Then the different det if all particles originating from the primary e MSSM is shown in Fig. 9(right) [43]. 3. Detector Design for the ILC precision limiting number in manythe theoretical strong predictions impact of uncertainties of parameter. Furthermore, when Figure 9: International Linear Collider: Physics and Detectors values of the top velocity parameter [42]. Right: Allowed re PoS(HEP2005)402 → → − − e e + cells is + 2 Klaus Desch th 1 cm Sc-Tiles. The inner y resolution of 60% 2 4 cm ) in the process e × er calorimeter radius. While on pairs in the process e -wide effort. In most cases the e infrastructure for ILC detector e sufficient to disentangle the two in Fig. 10. Here the reconstructed are pursuing the particle flow con- silicon detectors for tracking. In the s to rely on the hadronic calorimeter ILC collisions. Electromagnetically tor design concept in which it would ich is the goal for the ILC detectors, concept [44] employs a 5 T magnetic rimeter. This requires a fine segmen- ticle tracking and in the magnetic field ic and hadronic showers of all particles e, a large magnetic field and/or a large d and neutral particles in dense jets. tic calorimeter and only the energy mea- icle flow concept efficiently, the showers . Clearly the goal of ideal particle separa- SiD concept [45] has a 4 T field and relies on a large 14 LDC a Silicon-Tungsten electromagnetic calorimeter(ECAL) wi LDC relies on a Scintillator-Tungsten ECAL with crossed 1 are shown for 60% (left) and 30% (right) are shown. A jet energ and for a jet energy resolution of 60% (left) and 30% (right). Reconstructed masses of hadronically decaying W- and Z-bos GLD ZZ ZZ SiD / / concept [46] a 3 T magnetic field is compensated by an even larg R&D on the crucial detector components has started in a world The importance of good jet energy resolution is illustrated Currently three overall detector concepts are studied. All WW WW ¯ ¯ ν ν was reached in the ALEPH experiment.processes Clearly in this a would satisfactory not way. b a In radically order new to calorimeter arrive approach at has 30%, to wh be followed. radius of the ECAL is 125/168/186 cm for SiD/LDC/GLD. R&D on the sub-detectors is independentbe of implemented. the specific detec Recently, a EU-funded program to improve th foreseen, of individual particles must be made visible inside the calo Figure 10: ν which typically has the worst individual energy resolution will overlap in the calorimeter. In order to realize the part tation of the calorimeters ininner three radius dimensions. of the Furthermor calorimeter helps to disentangle charge ν surement for the remaining roughly 10% of neutral ha tion can only be reached approximately since electromagnet International Linear Collider: Physics and Detectors to the calorimetric measurement forinteracting the particles momenta can relevant be at measured in the electro-magne mass of two hadronically decaying weak gauge bosons (WW or ZZ cept. The main differences are inand the inner choices radius for charged of par the electromagneticfield calorimeter. and The an all-silicon tracking system.time The projection chamber (TPC) supplemented by fewGLD layers of both in PoS(HEP2005)402 ¯ b b → -boson. H Z Klaus Desch has to be achieved, 1 − GeV 5 − y of a beam-pipe radius as low f detector R&D for the ILC is ilicon strip detectors which give hers. for charged particle tracking are 10 the tagging of bottom and charm hieve the desired point resolution photon conversions. Sensor R&D × dent reconstruction and mass mea- chnologies are under active study: e is a general consensus that a four 5 on decays products. Driving physics ique. Here, the goal is to reconstruct solution. Here momentum resolution els very high momentum resolution is , in particular the separation of e scattering and secondary interactions )= t p / 1 ( m) point resolution. σ µ 15 100 m) space points or a huge µ Three detector concepts < ) silicon pixel detector will be used. The challenge lies in 2 m µ 20 Figure 11: × decays to precision much better than the natural width of the `` → Z 5) number of very precise (few ¯.Duec¯c. to the extremely small beam-spot and the possibilit ∼ → In the context of the particle flow concept, the requirements Two complementary approaches to achieve this are pursued: S In the case of Silicon tracking the major challenges are to ac High precision vertex detectors are mandatory at the ILC for H In order to achieve this, a momentum resolution and as 1 cm, unprecedented flavourto tagging five will layered be fine-grained (<20 possible. Ther the minimization of the necessaryas material well to limit as multipl achievingCCDs the [49], necessary DEPFET pixels readout [50], speed. CMOS pixel sensors Various [51] te and3.3 ot Charged Particle Tracking mainly high efficiency, robustness, and goodis less double important. track However re for some importantmandatory. physics The chann most prominent example issurement of the model-indepen the Higgs boson exploitingthe the mass recoil of mass techn the approximately a factor five better than achieved at LEP. a small ( with a minimum of material to reduce multiple scattering and with at least 200 space points of moderate ( International Linear Collider: Physics and Detectors R&D, EUDET, has been approvedkept [47]. at [48]. An world-wide register o 3.2 Vertex Detectors hadron as well as measuring thequestions impact are parameters the measurement of of tau the lept Higgs branching ratios PoS(HEP2005)402 2 Klaus Desch 80 cm), which ∼ ) or digital readout 2 e project. or enterprise in accelerator onference in Lisboa for their of Terascale physics and are evelopment of a high-resolution onal LC-TPC collaboration [53]. chnology has started within the In particular K. Mönig helped in Tungsten interleaved by 1x1 cm en up by the world-wide CALICE SY and KEK inside large magnetic hysics in the coming decades. With paration of these proceedings. prototype (diameter r the HCAL either stainless steel or yer may either consist of scintillator nd the GDE process having started, the e results presented in this talk are the ilities highly complementary to that of lectro-magnetic and hadronic sampling imeter has to be very compact in order s of hadronic showers. The construction t field cage, the development of new gas rt. eadout (size 5x5 sm rs like Micromegas and GEMs. Numerous E. Paige and P. Sphicas [ATLAS and CMS 16 (2002) N1. . The construction of such a fine-grained calorimeter needs 4 2 prototype is underway and a beam test is the midterm goal of th 3 Collaborations], Eur. Phys. J. directC Supported by a broad consensus, the ILC should be the next maj The author would like to thank the organizers of the HEP2005 c R&D for a large high precision TPC is ongoing in the internati The challenge to construct a particle flow calorimeter is tak [1] J. G. Branson, D. Denegri, I. Hinchliffe, F. Gianotti, F. [2] LEP Electro-Weak Working Group, hep-ex/0511027. 4. Conclusions a significant improvement in the understanding ofofa1m the detail based particle physics. It offersthe tremendous LHC. physics LHC capab andpowerful ILC tools together to allow enhance our for knowledgethe a about consensus comprehensive microscopic about p study the choice ofILC accelerating technology design a is put onILC a detector firm has basis. started in As a a world-wide part collaborative effo of this process, the5. d Acknowledgements hospitality and excellent organizationwork of of the many sessions. colleagues whosethe Th work preparation is of greatly the acknowledged. talk and P. Wienemann helped in the pre References with even higher granularity of 1x1 cm International Linear Collider: Physics and Detectors and development of newinternational readout SiLC ASIC’s collaboration [52]. in deep-sub-micron te The main topics are the construction of low-material-budge small prototypes have already beenfields. tested The in upcoming test major beams goal is at the DE construction of a large amplification end-plates using micro-pattern gas-detecto can be used to test all major design issues of3.4 the system. Calorimetry collaboration [54]. 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