Prospects and challenges for future ee and ep colliders Marcin - PowerPoint PPT Presentation

Prospects and challenges for future ee and ep colliders Marcin Chrzaszcz mchrzasz@cern.ch Physik-Insitut, University of Zurich Instiute of Nuclear Physics, Polish Academy of Sciences Neutrinos at the High Energy Frontier, Amherst, 18-20 July, 2017 Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 1/43 1 / 43

Outline Marcin Chrzaszcz (Universität Zürich) 2/43 Search for massive neutrinos at LHCb and discovery potential of the FCC ⇛ Future e + e − colliders. • ILC • CLIC • FCCee,eh ⇛ Detector ⇛ Physics program: • Higgs program. • Z pole program. • WW program. • t ¯ t program. • Neutrino program. 2 / 43

Quo Vadis HEP? Marcin Chrzaszcz (Universität Zürich) ... and what is still missing. matter/energy? What has LHC found... asymmetry? 3/43 Search for massive neutrinos at LHCb and discovery potential of the FCC ⇛ Dark ⇛ A Higgs boson. ⇛ Neutrino masses? m H = 125 GeV Γ H = 4 . 1 MeV ⇛ Matter/antimatter ⇛ LHC has ongoing physics program... ◦ Run 2 +3: 300 by 2023 ◦ HL-HLC: 3000 by 2035 ⇛ But what for post-LHC area? Need to plan now! 3 / 43

International Linear Collider (ILC) Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 4/43 4 / 43

International Linear Collider (ILC) that of ILC500”, Hiroaki Aihara Feedbacks (domestic only) 5/43 reserved/hostile Search for massive neutrinos at LHCb and discovery potential of the FCC reserved/critical Marcin Chrzaszcz (Universität Zürich) enthusiastic/cautious new physics is currently unknown, the physics reach of precision Higgs and other SM probes of ILC250 are comparable to ⇛ The ILC concept was reviewed by the Japanese government. ⇛ “Given the fact that the energy scale of ⇛ Academia in general: ⇛ Funding authorities: ⇛ Political allies (Local/Central): 5 / 43

Compact Linear Collider (CLIC) Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 6/43 ⇛ CLIC also wants a staged approach: 6 / 43

Future Circular Collider (FCC) FCC - study: area by the end of 2018! Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 7/43 ⇛ pp collider: the ultimate goal. ⇛ ee collider: first step. ⇛ ep collider: additional option. ◦ 98 km infrastructure in Geneva ⇛ The Goal: CDR and cost review 7 / 43

Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 8/43 8 / 43

Time line of FCC Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 9/43 9 / 43

Why circular collider? luminosity. cost? Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 10/43 ⇛ To achieve interesting physics program one would have to obtain a factor of 10 3 of LEP ⇛ The Luminosity scales: L ∼ RP SR β ∗ ⇛ So how can one increase the luminosity without the electric energy ⇛ The answer is inside the B-factory design! ⇛ One has to lower the beam emittance: β ∗ . 10 / 43

Why circular collider? luminosity. cost? Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 10/43 ⇛ To achieve interesting physics program one would have to obtain a factor of 10 3 of LEP ⇛ The Luminosity scales: L ∼ RP SR β ∗ ⇛ So how can one increase the luminosity without the electric energy ⇛ The answer is inside the B-factory design! ⇛ One has to lower the beam emittance: β ∗ . 10 / 43

Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 11/43 β ∗ over last 40 years ⇛ The β ∗ will be increased to 1mm compared to 5 cm at LEP. ⇛ SuperKEKB will pave the way towards β ∗ < 1 mm . ⇛ Additional improvements to reach the 10 3 factor in lumi are: • Continues injection • More bunches 11 / 43

Beam parameters Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 12/43 ⇛ Identical beam optics for all energies. ⇛ FCC would have two separate rings ⇛ Detectors similar to the ILC and CLIC. 12 / 43

Search for massive neutrinos at LHCb and discovery potential of the FCC Marcin Chrzaszcz (Universität Zürich) 13/43 Comparison of e + e − colliders 13 / 43

FCCep additional ERL anyway for FCChh. Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 14/43 ⇛ Requires ⇛ Would be needed 14 / 43

Detectors requirements Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 15/43 E.Leogrande 15 / 43

CLIC detector Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 16/43 E.Leogrande 16 / 43

Tracker Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 17/43 E.Leogrande 17 / 43

IDEA detector Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 18/43 M.Dam 18 / 43

Tracker Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 19/43 M.Dam 19 / 43

Tracker (for) the idea ;) Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 20/43 M.Dam 20 / 43

Physics program Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 21/43 21 / 43

Higgs production Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 22/43 22 / 43

Higgs Mass recoil technique (unique for lepton colliders): Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 23/43 ⇛ A very clean Higgs mass determination in e + e − → ZH and using a m recoil = ( √ s − E µ ) 2 − | p µ | 2 ⇛ With Z → µµ and Z → ee ⇛ ZH decays are tagged independently of the Higgs decay mode. ⇛ Precise measurement of g HZZ : 23 / 43

Higgs Width Marcin Chrzaszcz (Universität Zürich) 24/43 Search for massive neutrinos at LHCb and discovery potential of the FCC Credit to Mark Thomson ⇛ Higgs-strahlung. ⇛ Total HZ crossection: σ ( HZ ) ∝ g 2 HZZ ⇛ Exclusive cross section: g 2 σ ( HZ ) × Br ( H → XX ) ∝ g 2 HXX HZZ Γ H ⇛ Total Higgs width from WW process: σ ( HZ ) × Br ( H → b ¯ b ) ∝ g 2 b ) HZZ σ ( Hνν ) × Br ( H → b ¯ g 2 HWW ⇛ And finally: σ ( Hνν ) × Br ( H → WW ∗ ) ∝ g 4 HWW ∆ H ◦ From this: ∆ H . 24 / 43

Higgs Couplings determined via tagging the respective Higgs decay final states Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 25/43 c , gg , τ − τ + , γγ can be ⇛ The Higgs couplings to WW , ZZ , c ¯ ⇛ Observables: σ ( e + e − → ZH ) × Br ( H → X ) σ ( e + e − → Hνν ) × Br ( H → X ) 25 / 43 ⇛ Factor of 10 improvements for most couplings.

monochromatization (increasing the Higgs Production in S-channel energy resolution in the CMS energies for inherent energy spread of the colliding beams) Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 26/43 ⇛ Potentially possibility to measure the H ee Yukawa coupling! ⇛ Several final states can be studied. ⇛ It requires running: √ s = M H = 125 GeV ⇛ Since Γ H = 4 . 2 MeV , it requires e − e + interaction without reducing the ◦ Limits 3.5 times the SM predictions in both cases. 26 / 43

Normalized Higgs Couplings Marcin Chrzaszcz (Universität Zürich) Search for massive neutrinos at LHCb and discovery potential of the FCC 27/43 ⇛ Higgs couplings normalized to the SM predictions: k x = g H xx g SM H xx 27 / 43

to high precision (depends luminosity spectrum). 28/43 top quark to be studied using a precisely defined leptonic state. Search for massive neutrinos at LHCb and discovery potential of the FCC quark cross-section shape on the t quark mass and interactions is computable Marcin Chrzaszcz (Universität Zürich) MegaTop: t ¯ t threshold scan ⇛ For the first time the the ⇛ The dependence of the t on m t , Γ t , α s , g H tt , ISR, ⇛ PRD: m = (173 . 21 ± 0 . 51 ± 0 . 71) ⇛ FCCee: σ ( m t ) < 10 MeV 28 / 43

Physics program WW Marcin Chrzaszcz (Universität Zürich) Max statistical sensitivity at 29/43 Stat. precision Sys. precision needed: Search for massive neutrinos at LHCb and discovery potential of the FCC ⇛ Measurement of m W from σ WW ◦ with L = 11 pb − 1 → 350 MeV ◦ with L = 8 ab − 1 → 0 . 4 MeV ◦ ∆ E (beam) < 0 . 4 MeV ⇛ ◦ ∆ ϵ/ϵ < 10 − 4 √ s = 2 m W + 0 . 6 GeV ◦ ∆ σ B < 0 . 7 fb ∆ m FCC ∆m LEP = 500 keV = 50 MeV W W 29 / 43