Recent results from LHC(focusing on Higgs)

and synergy to Higgs Factories
25 November 2022, ILC-Japan Physics WG meeting
Shigeki Hirose (University of Tsukuba)

2/15■ LHC and ILC
LHC's territory
350 GeV• Top physics →Vacuum stability

250 GeV• Precision SM (𝑊, 𝑍, 𝑏, 𝜏, ...)
• Higgs couplings• Higgs rare decays> 1 TeV• Direct BSM searches(1 TeV Higgsino, 3 TeV
Wino, ...)

~500 GeV• Higgs self couplingҧ production• 𝑡𝑡𝐻
Reference: T. Suehara, JPS Fall 2022

• ILC can realise precision measurements, but needs extension toreach higher energy processes• LHC can cover wider range (depending on parton distribution), butlarge theory uncertainties and QCD background in general
Interplay between (HL-)LHC and ILC is important!

3/15■ Recent Higgs results

2nd generation!

ATLAS, Nature 607, 52 (2022)

CMS, Nature 607, 60 (2022)

𝜇 = 1.05 ± 0.06

𝜇 = 1.002 ± 0.057• Both experiments achieved the inclusive precision of 6%!
– Entering the second generation (𝜇, 𝑐)• Understanding of experimental / theoretical uncertainties arebeing more important■ Recent developments of 𝐻 → 𝑐𝑐ҧ

4/15ATLAS, EPJC 82 (2022) 717• Similar analysis technique with 𝐻 → 𝑏𝑏ത
– Use the 𝑉𝐻 production; existence of 𝑉 suppresses QCD background• Result: 𝜇 < 26 obs. (< 31 exp.)– Significantly improved from the previous publication: 𝜇 < 110 (150)
ATLAS, PRL 120 (2018) 211802• 3.9x more statistics• Better performance DNN-based c-tagging algorithm• Better 𝑐-tagging calibration, allowing to significantly reduce systematics• CMS: 𝜇 < 14.4 obs. (𝜇 < 7.60 exp.) CMS, arXiv:2205.05550 [accepted by PRL]
– Good sensitivity thanks to the boosted SR5/15

■ Differential measurement
𝐻 → 𝛾𝛾, 𝑊𝑊, 𝑍𝑍

ATLAS, Nature 607, 52 (2022)• Differential measurements
are more important– Simplified Template Cross
Section (STXS) framework
allows combinations fromvarious measurements– Important to measure withas many different channels
as possible– Precision of ~20-100% isachieved

𝐻 → 𝑊𝑊, 𝜏𝜏

𝐻 → 𝑏𝑏𝑡𝑡𝐻

Main contributing channels are shown by red• Genuine differential measurements beyond the STXS
framework is also being attempted– 𝐻 → 𝛾𝛾
– 𝐻 → 𝑍𝑍 ∗ → 4ℓ
– 𝐻 → 𝑊𝑊 ∗– 𝐻 → 𝜏𝜏

CMS, arXiv:2208.12279
ATLAS-CONF-2021-053
Presented at Higgs 2022
(CONF note coming soon)

Work In Progress

CMS-PAS-HIG-21-009
CMS, JHEP 03 (2021) 003
CMS, PRL 128 (2022) 081805

6/15■ Higgs self-coupling
ATLAS, PLB 800 (2020) 135103(Three years ago...)𝜎/𝜎SM < 3.4 obs. (< 2.5 exp.)-1.24 < 𝜅𝜆 < 6.49

ATLAS, arXiv:2211.01216(Now!)-0.4 < 𝜅𝜆 < 6.3 at 95% CL• All of the main channels are now (almost) complete– Significant improvements w.r.t. the previous publication!
• From 𝜎/𝜎SM < 10 to < 2.9 (in expectations) with 3.9x more statistics• CMS also shows good results

7/15■ Other Higgs properties
ATLAS-CONF-2022-068

ATLAS, PLB 784 (2018) 345

ATLAS, arXiv:2207.00320

New at Higgs 2022!

Γ𝐻 = 4.6+2.6-2.5 MeV

4ℓ: 124.92 ± 0.19 (stat) +0.09-0.06 (syst) GeV
𝛾𝛾: 124.93 ± 0.21 (stat) ± 0.34 (syst) GeV• Total decay width can be determined using off-shell 𝐻 ∗ → 𝑍𝑍
𝜇off−shell /𝜇on−shell = Γ𝐻 /Γ𝐻SM• Mass: 𝐻 → 𝛾𝛾 being dominated by systematics while 𝐻 →𝑍𝑍 ∗ → 4ℓ still statistically limited• CP-odd/even mixing on Higgs couplings being probed

8/15■ Projections to HL-LHCCERN Yellow Report (2018)• Realistic prospects for HL-LHC is made based on the latest
analysis techniques at Run 2– Not full simulations with upgraded detector geometries– Some assumptions in estimates of systematics– Various new updates in the past months for Snowmass 2022 process
ATL-PHYS-PUB-2022-018

■ 2nd generation fermions at HL-LHC
CMS-PAS-FTR-21-006

ATLAS-PHYS-PUB-2021-039• 𝐻 → 𝜇𝜇 projection by CMS– Included better tracking resolution and wider muon acceptance of theupgraded detector• Direct 𝐻 → 𝑐𝑐ҧ search included for the first time
ATLAS
𝜅𝜇

7.7% (7.7%)|𝜅𝑐 |< 3.0CMS
3.5% (5.0%) → ATLAS result not updated since YR18
< 3.4→ |𝜅𝑐 | < 2.5-5.5 was estimated by theorists
G. Perez et al., PRD 93, 013001 (2016)9/15

10/15■ Higgs self-coupling at HL-LHC
2018 [1]Latest (2022)

ത 𝑏ത𝐻𝐻 → 𝑏𝑏𝑏
ത
𝐻𝐻 → 𝑏𝑏𝜏𝜏

0.61σ

1.0σ [4]2.1σ

2.8σ [2]ത
𝐻𝐻 → 𝑏𝑏𝛾𝛾

2.0σ

2.2σ [3]All combined

3.0σ

3.4σ [4][1] ATL-PHYS-PUB-2018-053[2] ATL-PHYS-PUB-2021-044[3] ATL-PHYS-PUB-2022-001[4] ATL-PHYS-PUB-2022-053

2018 [1]ത 𝑏ത
𝐻𝐻 → 𝑏𝑏𝑏
ത
𝐻𝐻 → 𝑏𝑏𝜏𝜏

0.95σ

ത𝐻𝐻 → 𝑏𝑏𝛾𝛾∗
ത
𝐻𝐻 → 𝑏𝑏𝑊𝑊

1.8σ

0.56σ

ത ∗
𝐻𝐻 → 𝑏𝑏𝑍𝑍

0.37σ

All combined

2.6σ

Latest (2022)

1.4σ
2.16σ [2][1] CMS-FTR-18-019[2] CMS-FTR-21-004

ത 𝑏,ത 𝑏𝑏𝜏𝜏,ത 𝑏𝑏𝛾𝛾)ത• Three main channels (𝑏𝑏𝑏lead sensitivities– 4.0σ (0.52 < 𝜅𝜆 < 1.5) was predicted for 3000 fb-1 in YR18

• Various improvements developed in full Run-2 analyses– N.B. current nominal luminosity for HL-LHC is 4000 fb-1
(Observation of the 𝐻𝐻 production probably achievable at HL-LHC?)11/15■ EW precision: 𝑊 mass

ATLAS, EPJC 78 (2018) 110• ATLAS measured 𝑚𝑊 at 7 TeV

CDF II, Science 376, 170 (2022)– Less advantageous w.r.t. Tevatron due to pp collisions and higher 𝑠– 𝜒 2 fit of the templates with changing shape as a function of 𝑚𝑊– Update with improved methods is work in progress• Low pileup data were taken during Run 2– Need low pileup data to not degrade resolutions– 636 pb-1 data were collected at pileup ~2

12/15■ EW precision: top mass
CMS-PAS-TOP-20-008

S. Chigusa et al., PRD 97, 116012 (2018)

PDG
This result(Grey and red ellipses are put by me)• Latest CMS results with the lepton+jet channel– Kinematic fit using the 𝑚𝑡 = 𝑚𝑡ҧ to improve resolution– Five-dimensional fit to constrain systematics
𝑚𝑡 = 171.77 ± 0.04 (stat) ± 0.38 GeV

PDG: 172.69 ± 0.30 GeV• Good precision is achieved; the value moved slightly towards
Absolute Stability

■ EW SUSY

13/15
ATL-PHYS-PUB-2022-013• Slepton searches– There is a gap at 𝑚 ℓ෨ − 𝑚 𝜒෤10 ~40 GeV due to similarity to SM 𝑊𝑊;
but this phase space is motivated by the 𝑔 − 2 𝜇 anomaly– A dedicated analysis to tackle this region ATLAS, arXiv:2209.13935• Higgsino searches– Intermediate region below 𝑚 𝜒෤1± − 𝑚 𝜒෤10 ~1 GeV but still large
enough to not be long-lived 𝜒෤1±14/15■ Synergy with ILC
Higgs properties•Coupling: better precision expected in ILC if BR > O(1%)ҧ (w.r.t. ILC250)• HL-LHC has an advantage for 𝐻 → 𝜇𝜇 and 𝐻 → 𝛾𝛾 and 𝑡 𝑡𝐻
Self-coupling: HL-LHC important until ILC500 is realised
Decay width: will be determined with ~20% precision at HL-LHC; will be drastically
improved at ILC500 where WW fusion is usable (with model-independent method)
CP properties: HL-LHC and ILC may complement measurements each other? Goodstatistics in HL-LHC, while cleaner environment in ILC

250 GeV •••Top properties

350 GeV •Top mass: precise measurements (~100 MeV or less?) by the 𝑡𝑡ҧ threshold scan
• HL-LHC prospect is ~200 MeV
Kinematic properties: top quark dynamics can be probed using enormous 𝑡 𝑡ҧ events
at HL-LHC: O(109) with 4000 fb-1•

500 GeV

Heavy BSM searches••>1 TeV

Strong production: high statistics at HL-LHC may enable us to discover them (ifwithin the range of HL-LHC)
EW production: ILC>1000 may be possible to access O(TeV) BSM resonances, suchas 1 TeV Higgsino?
• ILC350-500 can already open new phase space w.r.t. HL-LHC?

N.B. various other topics (SM precision measurements, lightresonance searches, ...) are of course important!

■ Summary

15/15• Diverse physics programs are ongoing at LHC– The topics shown today are only tiny part of them
– High mass resonance searches (heavy Higgs, SUSY, LQ, ...) are ofcourse important (though not well covered today)– Statistics will be ~tripled by the end of Run 3 (139 fb-1 → 400 fb-1)→ Physics at Run 3 must be very interesting!

• Projections to HL-LHC– Not only statistics, but also analysis techniques which are being
improved– The prospect of 𝜎𝐻𝐻 significance at HL-LHC was improved by >10% in
four years• Interplay with ILC will be more important at the HL-LHC era– Some processes are already being limited by theory systematics→ ILC may reach better precisions than HL-LHC– If we see deviations from expectations, LHC can directly tackle possible
BSM resonances

16/15

17/15■ ATLAS c-tagging• eff(c) = 27%~23%(?)

ATLAS, PRL 120 (2018) 211802

18/15■ Hcc: systematics
ATLAS, PRL 120 (2018) 211802

ATLAS-PHYS-PUB-2021-039

■ VHcc: ATLAS vs CMS
ATLAS, EPJC 82 (2022) 717

19/15
CMS, arXiv:2205.05550 [accepted by PRL]

• CMS shows a better result– Boosted region plays a good job; probably thanks to good S/N though
expected signals are small

20/15■ STXS/differential
ATLAS, Nature 607, 52 (2022)

ATLAS, ATLAS-CONF-2021-053

■ Contributions to κλATLAS, arXiv:2211.01216

21/15

■ HH search at CMS

22/15

23/15■ Off-shell H→ZZ
• 4 lepton channel: use optimal observables
ATLAS-CONF-2022-068

24/15

25/15