TLEP a first step on a long vision

TLEP: a first step on a long vision for HEP M. Koratzinos Univ. of Geneva On behalf of the TLEP study group Beijing, 16 August 2013 1

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A preamble “…we chose these things not because they are easy, but because they are hard, because that goal will serve to measure and organize the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win”: J. F. Kennedy, president of the US, 1962 3

On challenges… The ILC community has taken a formidable challenge and have managed to come with a solid design and TDR on what is a very tricky machine but The Higgs is light and there is not yet any hint of new physics! So, the circular collider approach should be given a chance. It already promises better performance than an equivalent linear machine. We need to allow the circular approach to reach CDR level and compare. 4

Contents • • • The physics case Circular collider challenges TLEP implementation TLEP physics reach TLEP design study Acknowledgements: I am indebted to the whole TLEP community and especially R. Aleksan, A. Blondel, P. Janot, F. Zimmermann for liberal use of material This talk would not have been complete without the comparison data with the ILC. I hope I have represented them accurately 5

The physics case • The energy scale of any new physics is already pushed to beyond a few hundreds of Ge. V and will probably be pushed to 1 Te. V or more with the next LHC run. • In this scenario, Physics beyond the standard model is only accessible via loop corrections rather than direct observation of a (heavy) state. • The sensitivity of precision measurements can be to energy scales far above what is directly accessible in current or next generation machines (LHC, ILC, CLIC) • A clearer picture on this will emerge after the next LHC run. • Meaningful over-constraining of the standard model can only start now that the Higgs sector is known and might lead to revealing weaknesses of the standard model 6

Precision needed • 7

Circular colliders • In the next few slides I would like to overview the parameters that affect circular collider performance. • I will then show what can reasonably be achieved in terms of luminosity. • The following is not TLEP specific; it can apply to any circular machine (CEPC? ) 8

Major limitations • The major limitations of circular colliders are: – Power consumption limitations that affect the luminosity – Tunnel size limitations that affect the luminosity and the energy reach – Beam-beam effect limitations that affect the luminosity – Beamstrahlung limitations that affect beam lifetimes (and ultimately luminosity) 9

Energy reach • In a circular collider the energy reach is a very steep function of the bending radius. To make a more quantitative plot, I have used the following assumptions: – RF gradient: 20 MV/m – Dipole fill factor: 90% (LEP was 87%) • I then plot the energy reach for a specific ratio of RF system length to the total length of the arcs 10

Energy reach 14000 12000 bending radius (m) 10000 8000 5% RF 2% RF 6000 1% RF Assumptions: 20 m. V/m, 90% dipole fill factor. What is plotted is the ratio of RF length to total arc length 4000 2000 0 100 150 200 250 300 350 beam energy (Gev) TLEP 175 sits comfortably below the 1% line LEP 2 had a ratio of RF to total arc length of 2. 2% 11

Luminosity of a circular collider • 12

Luminosity of a circular collider • 13

Total power • Luminosity is directly proportional to the total power loss of the machine due to synchrotron radiation. • In our approach, it is the first parameter we fix in the design (the highest reasonable value) • Power loss is fixed at 100 MW for both beams (50 MW per beam) 14

Machine radius • The bending radius of the collider also enters linearly in the luminosity formula • The higher the dipole filling factor, the higher the performance • [there is a small dependance on the maximum beam-beam parameter since smaller machines for the same beam energy can achieve higher beam-beam parameters] 15

Beam-beam parameter • 16

Maximum beam-beam • 17

Beta* and hourglass We are opting for a realistic β*y value of 1 mm. σz beam sizes vary from 1 mm to 3 mm. In this range the hourglass effect is between 0. 9 to 0. 6 R for beta*_y of 1 mm 1 Self-consistent σz at different energies for TLEP 0, 9 reduction factor 0, 8 0, 7 0, 6 0, 5 0, 4 0, 3 0, 5 1 1, 5 2 2, 5 sigma_z (mm) 3 3, 5 4 4, 5 18

Luminosity of a circular collider 1, 00 E+36 Luminosity [cm− 2 s− 1] 1, 00 E+35 1, 00 E+34 1, 00 E+33 0 50 100 150 beam energy [Ge. V] 200 250 19

Beamstrahlung • Beamstrahlung is the interaction of an incoming electron with the collective electomagnetic field of the opposite bunch at an interaction point. • Main effect at circular colliders is a single hard photon exchange taking the electron out of the momentum acceptance of the machine. • If too many electrons are lost, beam lifetime is affected • [the beamstrahlung effect at linear colliders is much larger and it increases the beam energy spread] 20

Beamstrahlung (2) • 21 *: ar. Xiv: 1203. 6563

Comparison with simulation The Telnov formula was checked against a realistic simulation (Guineapig – courtesy the ILC) at different energies [work of M. Zanetti] and found to be pessimistic TLEP-t comparison TLEP-H comparison 1000, 00 100, 00 TLEP-t Telnov tuned 10, 00 0, 015 0, 025 momentum acceptance 0, 03 lifetime (seconds) 1000, 00 100, 00 TLEP-H Telnov tuned 10, 00 0, 015 0, 025 momentum acceptance 0, 03 The ‘tuned’ model corresponds to an ad hoc tuning of the Telnov formula to fit the data better: instead of 10% of the electrons seeing a 100% field, 100% of electrons see a 70% field 22

Beamstrahlung limitation 1, 00 E+05 beam lifetime (sec) 1, 00 E+04 1, 00 E+03 Telnov tuned 1, 00 E+02 1, 00 E+01 Plot on left is if we run with a value of the beam-beam parameter of 0. 1 Above ~180 Ge. V is difficult to run without opting for a more modest beam-beam parameter value (which would reduce the luminosity) 1, 00 E+00 120 140 160 beam energy (Ge. V) 180 200 TLEP Latest parameter set, mom. acceptance 2. 2% Can even run at 250 Ge. V with a beam-beam parameter of 0. 05 23

A specific implementation: TLEP • A study has been commissioned for an 80 -km tunnel in the Geneva area. • For TLEP we fix the radius (conservatively 9000 m) the power (100 MW) and try to have beams as flat at possible to reduce beamstrahlung. • Our arc optics design (work in progress) conservatively uses a cell length of 50 m, which still gives a horizontal emittance of 2 nm at 120 Ge. V • We assume that we can achieve a horizontal to vertical emittance ratio of 500 -1000 (LEP was 200) LHC Possible TLEP location 24

Other tunnel diameters • …but of course other tunnel diameters and locations are equally good • Many other proposals floating, but I would like to mention the Circular Electron-Positron Collider in China (CEPC) – certainly the tunnel can be built more cheaply in China • Performance scales with tunnel size, but in case no funds are available for a new tunnel, the LHC tunnel can be used after the end of the LHC physics programme (a project we call LEP 3) 25

TLEP implementation q At 350 Ge. V, beams lose 9 Ge. V / turn by synchrotron radiation u u q RF Coupler (ESS/SPL) Luminosity is achieved with small vertical beam size : sy ~ 100 nm u q Need 600 5 -cell SC cavities @ 20 MV/m in CW mode l Much less than ILC (8000 9 -cell cavities@ 31 MV/m) l Length ~900 m, similar to LEP (7 MV/m) 200 k. W/ cavity in CW : RF couplers are challenging BNL 5 -cell 700 MHz cavity l Heat extraction, shielding against radiation, … A factor 30 smaller than at LEP 2, but much more relaxed than ILC (6 -8 nm) l TLEP can deliver 1. 3 × 1034 cm-2 s-1 per collision point at √s = 350 Ge. V Small beam lifetime due to Bhabha scattering ~ 15 minutes u Need efficient top-up injection A. Blondel F. Zimmermann Patrick Janot 26

Super. KEKB: a TLEP demonstrator • Super. KEKB will be a TLEP demonstrator • Beam commissioning starts early 2015 • Some Super. KEKB parameters : – Lifetime : 5 minutes • TLEP : 15 minutes – b*y : 300 mm • TLEP : 1 mm – sy : 50 nm • TLEP : ~100 nm – ey/ex : 0. 25% • TLEP : 0. 20%-0. 10% – Positron production rate : 2. 5 × 1012 / s • TLEP : < 1 × 1011 / s – Off-momentum acceptance at IP : ± 1. 5% • TLEP : ± 2. 0 to ± 2. 5% 27

TLEP Cost (Very Preliminary) Estimate q Cost in billion CHF Cost for the 80 km version : the 100 km version might be cheaper. ) y r a n i m i l y e r d o P b y l y e n t a u l y o b s d b Cost per Higgs boson : 1 - 3 k. CHF / Higgs e A s r o (ILC cost : 150 k$ / Higgs) [ NB : 1 CHF ~ 1$ ] d n e t o N Bare tunnel 3. 1 (1) Services & Additional infrastructure (electricity, cooling, service cavern, RP, ventilation, access roads …) 1. 0(2) RF system 0. 9 (3) Cryo system 0. 2 (4) Vacuum system & RP 0. 5(5) Magnet system for collider & injector ring 0. 8(6) Pre-injector complex SPS reinforcements 0. 5 Total 7. 0 (1): J. Osborne, Amrup study, June 2012 As a self-standing project : Same order of magnitude as LHC As an add-on to the VHE-LHC project : Very cost-effective : about 2 -3 billion CHF Note: detector costs not included – count 0. 5 per detector (LHC) LEP/LHC (2): Extrapolation from LEP (3): O. Brunner, detailed estimate, 7 May 2013 (4): F. Haug, 4 th TLEP Days, 5 April 2013 80 -100 km tunnel (5): K. Oide : factor 2. 5 higher than KEK, estimated for 80 km ring (6): 24, 000 magnets for collider & injector; cost per magnet 30 k. CHF (LHe. C); Patrick Janot 28

Power consumption Highest consumer is RF: RF systems cryogenics top-up ring Total RF TLEP 120 TLEP 175 173 -185 MW 10 MW 34 MW 3 MW 5 MW 186 -198 MW 212 -224 MW Limited by Klystron CW efficiency of 65%. This is NOT aggressive and we hope to be able to do better after dedicated R&D Total power consumption for 350 Ge. V running: Power consumption RF including cryogenics cooling ventilation magnet systems general services Total TLEP 175 224 MW 5 MW 21 MW 14 MW 20 MW ~280 MW CERN 2010 power demand: • Full operation 220 MW • Winter shutdown 50 MW IPAC 13 TUPME 040, ar. Xiv: 1305. 6498 [physics. acc-ph] 29

A note on power consumption • TLEP is using ~280 MW while in operation and probably ~80 MW between physics fills. So for 1× 107 sec of operation and 1× 107 sec of stand-by mode, total electricity consumption is ~1 TWh • CERN is currently paying ~50 CHF/MWh • TLEP yearly operation corresponds to ~50 MHF/year • This should be seen in the context of the total project cost (less than 1% of the total cost of the project goes per year to electricity consumption) 30

TLEP parameter set TLEP Z Ebeam [Ge. V] circumf. [km] beam current [m. A] #bunches/beam #e−/beam [1012] horiz. emit. [nm] vert. emit. [nm] bending rad. [km] κε mom. c. αc [10− 5] Ploss, SR/beam [MW] β∗x [m] β∗y [cm] σ∗x [μm] σ∗y [μm] hourglass Fhg ESRloss/turn [Ge. V] VRF, tot [GV] dmax, RF [%] ξx/IP ξy/IP fs [k. Hz] Eacc [MV/m] eff. RF length [m] f. RF [MHz] δSRrms [%] σSRz, rms [cm] 45 80 1180 4400 1960 30. 8 0. 07 9. 0 440 9. 0 50 0. 5 0. 1 124 0. 27 0. 71 0. 04 2 4. 0 0. 07 1. 29 3 600 700 0. 06 0. 19 5600 number of IPs beam lifet. [min] 4 67 TLEP W 80 80 124 600 200 9. 4 0. 02 9. 0 470 2. 0 50 0. 5 0. 1 78 0. 14 0. 75 0. 4 2 5. 5 0. 10 0. 45 3 600 700 0. 10 0. 22 1600 4 25 TLEP H TLEP t 120 80 24. 3 80 40. 8 9. 4 0. 02 9. 0 470 1. 0 50 0. 5 0. 1 68 0. 14 0. 75 2. 0 6 9. 4 0. 10 0. 44 10 600 700 0. 15 0. 17 480 175 80 5. 4 12 9. 0 10 0. 01 9. 0 1000 1. 0 50 1 0. 1 100 0. 10 0. 65 9. 2 12 4. 9 0. 10 0. 43 20 600 700 0. 22 0. 25 130 4 16 4 20 IPAC 13 TUPME 040, ar. Xiv: 1305. 6498 [physics. acc-ph] Too pessimistic! 2 nm @120 Ge. V or lower should he easy By definition, in a project like TLEP, from the moment a set of parameters is published it becomes obsolete and we now already have an improved set of parameters. The new parameter set contains improvements to our understanding, but does not change the big picture. Revised (taking into account BS) but similar 31

Luminosity of TLEP Z, 2. 1036 TLEP : Instantaneous lumi at each IP (for 4 IP’s) Instantaneous lumi summed over 4 IP’s WW, 6. 1035 HZ, 2. 1035 tt , 5. 1034 Why do we always quote 4 interaction points? • It is easier to extrapolate luminosity from the LEP experience. Lumi of 2 IPs is larger than half the lumi of 4 IPs • According to a particle physicist: “give me an experimental cavern and I guarantee you that it will be filled” 32

Upgrade path • TLEP offers the unique possibility to be followed by a 100 Te. V pp collider (VHE-LHC) • Luminosity upgrade: a study will be launched to investigate if luminosity can be increased by a significant factor at high energies (240 and 250 Ge. V ECM) by using a charge-compensated scheme of four colliding beams. We will aim to gain a factor of 10 (to be studied and verified) 33

TLEP : Possible Physics Programme q Higgs Factory mode at √s = 240 Ge. V: 5+ years u q Top Threshold scan at √s ~ 350 Ge. V: 5+ years u q Get 108 W decays; Measure the W mass; Precise W studies. l Continuous transverse polarization of some bunches and returns to the Z peak. Longitudinally polarized beams at √s = m. Z: 1 year u q Get 1012 Z decays @ 15 k. Hz/IP. Repeat the LEP 1 Physics Programme every 15 minutes. l Continuous transverse polarization of some bunches for precise Ebeam calibration WW threshold scan at √s ~ 161 Ge. V: 1 -2 years u q Top quark mass, width, Yukawa coupling; top quark physics; more Higgs boson studies. l Periodic returns at the Z peak for detector and beam energy calibration Z resonance scan at √s ~ 91 Ge. V: 1 -2 years u q Higgs boson properties, WW and ZZ production. l Periodic returns at the Z peak for detector and beam energy calibration Get 1011 Z decays, and measure ALR, AFBpol, etc. l Polarization wigglers, spin rotators Luminosity, Energy, Polarization upgrades u If justified by scientific arguments (with respect to the upgrade to VHE-LHC) Patrick Janot 34

TLEP as a Mega-Higgs Factory (1) Unpolarized cross sections PJ and G. Ganis Z → All Z → nn Patrick Janot ILC-250 TLEP-240 ILC-350 TLEP-350 Lumi / 5 yrs 250 fb-1 10 ab-1 350 fb-1 2. 6 ab-1 Beam Polarization 80%, 30% – # of HZ events 70, 000 2, 000 65, 000 325, 000 # of WW→H events 3, 000 50, 000 20, 000 65, 000 35

TLEP as a Mega-Higgs Factory (2) q Example : e+e- → ZH → l+l- + anything u Measure s. HZ e- Summary of the possible measurements : H (TLEP : CMS Full Simulation + some extrapolations for cc, gg) ILC TDR From P. Azzi et al. ar. Xi. V: 1208. 1662 ILC-250 TLEP-240 s. HZ 2. 5% 0. 4% s. HZ *BR(H→bb) 1. 1% 0. 2% s. HZ *BR(H→cc) 7. 4% 1. 2% s. HZ *BR(H→gg) 9. 1% 1. 4% s. HZ *BR(H→WW) 6. 4% 0. 9% s. HZ *BR(H→tt) 4. 2% 0. 8% s. HZ *BR(H→ZZ) 19% 3. 1% s. HZ *BR(H→gg) 35% 3. 0% s. HZ *BR(H→mm) 100% 13% INV / H < 1% < 0. 2% m. H 40 Me. V 8 Me. V Z* e+ g. HZZ Z e-, e+, m+ TLEP-240 1 year 1 detector Patrick Janot m- 36

Global fit of the Higgs couplings q Model-independent fit M. Bachtis Coupling g. Z g. W gb gc gg gt gm gg BRexo LEP-240 0. 16% 0. 85% 0. 88% 1. 0% 1. 1% 0. 94% 6. 4% 1. 7% 0. 48% LEP-350 0. 15% 0. 19% 0. 42% 0. 71% 0. 80% 0. 54% 6. 2% 1. 5% 0. 45% ILC-350 0. 9% 0. 5% 2. 4% 3. 8% 4. 4% 2. 9% 45% 14. 5% 2. 9% 1. 0% u NB : Theory uncertainties must be worked out. Patrick Janot Snowmass 2013 37

TLEP as a Mega-Top Factory - q M. Zanetti TLEP, TLEP ILC Expected sensitivity for TLEP (full study to be done) and ILC Lumi / 5 years # top pairs mtop ltop/ltop TLEP 4 × 650 fb-1 1, 000 10 Me. V 12 Me. V 13% ILC 350 fb-1 100, 000 30 Me. V 35 Me. V 40% Patrick Janot Stat. only 38

TLEP as a Tera-Z and Oku-W Factory (1) q TLEP repeats the LEP 1 physics programme every 15 minutes Added value: Transverse polarization up to the WW threshold (LEP: up to 60 Ge. V) l Exquisite beam energy determination with resonant depolarization è Up to 5 ke. V precision – unique at circular e+e- colliders u Measure m. Z, m. W, Z, … with unbeatable accuracy Z lineshape, asymetries WW threshold scan New Physics in loops ? u u Measure the number of neutrinos l From the peak cross section at the Z pole – Luminosity measurement is a challenge l From radiative returns to the Z from the WW threshold – e+e- → g Patrick Janot No beamstrahlung is a clear advantage 39

TLEP as a Tera-Z and Oku-W Factory (2) q q This is a unique part of the TLEP programme (that was not covered by the snowmass reports yesterday). It is also very challenging for the accelerator (intensity, longitudinal polarization), experiments (rate) and Theory Measurements with Tera-Z u u u q Measurements with Oku-W u u q Caution : TLEP will have 5× 104 more Zs than LEP - Predicting achievable accuracies with 250 times smaller statistical precision is difficult The study is just beginning : errors might get better with increasing understanding Much more to do at the Z peak e. g. , asymmetries, flavour physics (>1011 b, > 1011 c, > 1010 t), rare Z decays, … Caution : TLEP will have 5× 106 more W than LEP at the WW threshold -Predicting achievable accuracies with 1000 times smaller statistical precision is difficult Much more W physics to do at the WW threshold and above e. g. , GW, l. W, rare W decays, diboson couplings, … Measurement with longitudinal polarization u One year data taking with luminosity reduced to 20% of nominal (requires spin rotators) l 40% beam longitudinal polarization assumed – NB: LEP kept polarization in collisions 40 hardware needed is challenging NB: ILC limited to a factor > 30 larger errors

EWSB Precision tests at TLEP: Teaser lkjfs Warning : indicative only. Complete study being done ILC m H =1 26 Ge V q TLEP Very stringent SM closure test. Sensitivity to weakly-interacting BSM Physics at a scale > 10 Te. V Patrick Janot 41

TLEP Design Study: Structure 26 Working Groups: Accelerator / Experiment / Phenomenology 42

TLEP Design Study: People 296 • 295 subscribers from 23 countries (+CERN) – Distribution reflects the level of awareness in the different countries • 4 physicists from China: subscribe at http: //tlep. web. cern. ch ! 43

Watch this space • http: //tlep. web. cern. ch • Next event : Sixth TLEP workshop 16 -18 October 2013 http: //indico. cern. ch/conference. Display. py? ovw=True&conf. Id=25771 • Joint VHE-LHC + TLEP kick-off meeting in February 2014 44

Conclusions • TLEP is a 3 -in-1 package: – It is a powerful Higgs factory – It is a high-intensity EW parameter buster – It offers the path to a 100 Te. V pp collider • TLEP is based on solid technology and offers little risk, has a price tag which is expensive but not out of reach, has reasonable consumption, offers multiple interaction points and might even have an upgrade potential. 45

Concluding remarks Ge. V OR Ge V ? The debate has started and we are looking forward to upgrades and performance improvements from both sides 46

end THANK YOU 47

Extra slides 48

Beamstrahlung • I am using the approach of Telnov throughout* • The energy spectrum of emitted photons during a collision of two intense bunches (usual bremstrahlung formula) is characterized by a critical energy • Where ρ is the radius of curvature of the affected electron which depends on the field he sees • And the maximum field can be approximated by 49 *: ar. Xiv: 1203. 6563

Beamstrahlung • So, the critical energy turns out to be constants for the maximum field (it would be smaller for a smaller field) Telnov’s approximation: • 10% of electrons see maximum field • 90% of electrons see zero field 50

Beamstrahlung • 51

Beamstrahlung energy dependence • For a specific ring, power consumption, emittances and ξ: • Number of particles per bunch scales with gamma: • And u scales with γ 2. This produces a steep drop in lifetime with increased energy 52

European Strategy recommendations large-scale scientific activities d) • To. High-priority stay at the forefront of particle physics, Europe needs to be in a position to propose an ambitious post-LHC accelerator project at CERN by the#2 time of the next Strategy update, when – Second-highest priority, recommendation physics results from the LHC running at 14 Te. V will be available. CERN should undertake design studies for accelerator projects in a global context, with emphasis on proton-proton and electron-positron high-energy frontier machines. These design studies should be coupled to a vigorous accelerator R&D programme, including high-field magnets and high-gradient accelerating structures, in collaboration with national institutes, laboratories and universities worldwide. The two most promising lines of development towards the new high energy frontier after the LHC are proton-proton and electron-positron colliders. Focused design studies are required in both fields, together with vigorous accelerator • adequate Excerpt from the CERN Council deliberationinvolving document (22 -Mar-2013) R&D supported by resources and driven by collaborations CERN and national institutes, universities and laboratories worldwide. The Compact Linear Collider (CLIC) is an electron-positron machine based on a novel two-beam acceleration technique, which could, in stages, reach a centre-of-mass energy up to 3 Te. V. A Conceptual Design Report for CLIC has already been prepared. Possible proton-proton machines of higher energy than the LHC include HE-LHC, roughly doubling the centre-of-mass energy in the present tunnel, and VHE-LHC, aimed at reaching up to 100 Te. V in a new circular 80 km tunnel. A large tunnel such as this could also host a circular e+e- machine (TLEP) reaching energies up to 350 Ge. V with high luminosity. 53

CERN medium term plan 54

The TLEP tunnel • Standard size tunnel boring machines dictate a larger tunnel size of 5. 6 m diameter (LHC: 3. 8 m) • Maximize boring in ‘molasse’ (soft stone) • 80 km design necessitates a bypass tunnel to avoid very deep shafts at points 4 and 5 • A larger tunnel might actually be cheaper • This is only the beginning of the geological study 55

Global fit of the Higgs couplings (2) q Model-dependent (seven-parameter) fit a-la-LHC u Assume no exotic Higgs decays, and kc = kt HL-LHC : One experiment only … CMS Scenario 1 CMS Scenario 2 CMS, July 13 (HL-LHC : One experiment only) u u In bold, theory uncertainty are assumed to be divided by a factor 2, experimental uncertainties are assumed to scale with 1/√L, and analysis performance are assumed to be identical as today Quantitative added value from ILC – wrt HL-LHC – does not stick out clearly. l In contrast, sub-per-cent TLEP potential is striking for all couplings è Only TLEP is sensitive to (multi-)Te. V new physics with Higgs measurements Much theoretical progress is needed to reduce accordingly theory uncertainties Patrick Janot 56

TLEP as a Mega-Higgs Factory (3) q Determination of the total width u From the number of HZ events and of ZZZ events at √s = 240 Ge. V u From the bb final state at √s = 350 Ge. V (and 240 Ge. V) nn H from: ILC TLEP HZ →ZZZ @ 240 20% 3. 2% WW→H @240 12% 2. 4% WW→H @350 7% 1. 2% Combined 5. 8% 1. 0% Note : mm collider DGH/GH ~ 5% Patrick Janot 57

Higgs Physics with √s > 350 Ge. V ? (1) q Signal cross sections in e+e- collisions + H H q Measurements at higher energy u u u √s > 350 Ge. V does not do much for couplings to c, b, g, Z, W, g, m and tot. (slide 15) l Invisible width best done at √s = 240 Ge. V The tt. H coupling benefits from higher energy l TLEP 350 : 13% l ILC 500 : 14% ; ILC 1 Te. V : ~4% ; CLIC : ~4% The HL-LHC will already do the measurement with 5% precision (and improving) l Sub-per-cent precision will need the ultimate pp machine at 100 Te. V : VHE-LHC Patrick Janot 58

Higgs Physics with √s > 350 Ge. V ? (2) q Measurements at higher energy (cont’d) u Higgs tri-linear self coupling l very difficult for all machines Particularly difficult for √s < 2 -3 Te. V Few per-cent precision will need VHE-LHC J. Wells et al. ar. Xi. V: 1305. 6397 Snowmass, Aug 13 ILC 500, HL-LHC 0. 5 ab-1 q 3 ab-1 ILC 1 Te. V, HE-LHC 1 ab-1 3 ab-1 CLIC 3 Te. V, VHE-LHC 2 ab-1 3 ab-1 Summary u For the study of H(126), the case for e+e- collisions above 350 Ge. V is not compelling. l A stronger motivation will exist if a new particle found (or inferrred) at LHC è IF e+e- collisions can bring substantial new information about it Patrick Janot 59

EW parameter summary Quantity Physics Present precision TLEP Stat errors Possible TLEP key Syst. Errors Challenge Alain Blondel, Snowmass on Minnesota, 2 August 2013 MZ (ke. V) Input 91187500 2100 Z Line shape scan 5 ke. V <100 ke. V E_cal QED corrections Z (ke. V) (T) (no !) 2495200 2300 Z Line shape scan 8 ke. V <100 ke. V E_cal QED corrections Rl s , b 20. 767 0. 025 Z Peak 0. 0001 <0. 001 Statistics QED corrections N PMNS Unitarity sterile ’s 2. 984 0. 008 Z Peak 0. 00008 <0. 004 N PMNS Unitarity sterile ’s 2. 92 0. 05 ( +Z_inv) ( +Z ll) 0. 001 (161 Ge. V) <0. 001 Statistics Rb b 0. 21629 0. 00066 Z Peak 0. 000003 <0. 000060 Statistics, Hemisphere small IP correlations ALR , 3 , (T, S ) 0. 1514 0. 0022 Z peak, polarized 0. 000015 <0. 000015 4 bunch scheme, > 2 exp Design experiment MW Me. V/c 2 , 3 , 2, (T, S, U) 80385 ± 15 Threshold (161 Ge. V) 0. 3 Me. V <0. 5 Me. V E_cal & Statistics QED corections mtop Me. V/c 2 Input 173200 ± 900 Threshold scan 10 Me. V <10 Me. V E_cal & Statistics Theory interpretation 60 40 Me. V? Bhabha scat.