Tagging strange jets & constraining h s s Matthias Schlaffer - PowerPoint PPT Presentation

Tagging strange jets & constraining h → s ¯ s Matthias Schlaffer Weizmann Institute of Science based on: 1811.09636 (J. Duarte-Campderros, G. Perez, MS, A. Soffer) work in progress 4th NPKI workshop, Seoul May 2019

Gauge boson masses Higgs is main source of electroweak symmetry breaking! -1 35.9 fb (13 TeV) CMS Observed ± σ ⊕ 1 (stat syst) ± σ ⊕ 2 (stat syst) ± σ 1 (syst) γ γ µ µ X = BR X | meas. BR X | SM µ ZZ µ WW µ τ τ µ bb µ µ µ − − 2 1 0 1 2 3 Parameter value [CMS: 1809.10733] Higgs couples to gauge bosons as expected Matthias Schlaffer 1

What about fermion masses and the flavor structure? SM: economic solution, Higgs does it! h v ⇒ ⇒ m ψ ∝ y ψ ψ ψ ψ Does it? -1 35.9 fb (13 TeV) V t v 1 m CMS Z ✸ tth , h → ττ , h → bb > 5 σ ( � ) W V κ or − 1 10 ✸ h → µµ : µ µµ < 2 . 8 at 95 % CL F m v b F κ τ − 2 10 [ATLAS: 1705.04582] SM Higgs boson ε (M, ) fit − 3 µ 10 ± σ 1 Other fermions, especially quarks, ± σ 2 much less constrained − 10 4 Ratio to SM 1.5 ⇒ flavor puzzle unsolved 1 0.5 E.g. Yukawa modifications 0 − 1 2 10 1 10 10 Particle mass [GeV] [CMS: 1809.10733] Matthias Schlaffer 2

Difficulties i) small branching ratio Branching Ratio LHC HIGGS XS WG 2016 1 b b WW gg -1 10 τ τ c c ZZ -2 10 γ γ -3 10 γ Z [LHCHXSWG] µ µ -4 10 120 121 122 123 124 125 126 127 128 129 130 M [GeV] n e H m o g m r n n s n o t o r g c w a a t g e u u t p p o r h o m a i o l t H e u d s c b t t | | | | | | | | | | Mass [ eV ] 10 6 10 7 10 8 10 9 10 10 10 11 10 12 Matthias Schlaffer 3

Difficulties i) small branching ratio ii) difficult final state for quarks Branching Ratio LHC HIGGS XS WG 2016 1 > quarks appear as jets b b WW > large background gg -1 10 τ τ > hard to distinguish c c ZZ Nevertheless: -2 10 h → cc will be measured at % γ γ level at FCC-ee -3 10 γ Z [Dawson et.al ’13] [LHCHXSWG] µ µ -4 10 120 121 122 123 124 125 126 127 128 129 130 What about strange? M [GeV] n e H m o g m r n n s n o t o r g c w a a t g e u u t p p o r h o m a i o l t H e u d s c b t t | | | | | | | | | | Mass [ eV ] 10 6 10 7 10 8 10 9 10 10 10 11 10 12 Matthias Schlaffer 3

Exclusive decay h → φγ [Bodwin et.al ’13, Kagan et.al ’14] φ φ � � ¯ s s ¯ s s + h h γ γ s ) + K − (¯ s ) → K + ( u ¯ > Clean decay: BR ( φ ( s ¯ us )) ≈ 50% > BUT: BR ( h → φγ ) ≈ 2 × 10 − 6 [König et.al ’15] s ) ≈ 2 × 10 − 4 > compare BR ( h → s ¯ > only weak limit at future (hadron) colliders [Kagan et.al ’14] estimate: µ ss � O (10 7 ) @HL-LHC > current limit: BR ( h → φγ ) < 4 . 8 × 10 − 4 [ATLAS ’17] Ideas to use differential distributions [see e.g. Bishara et.al ’16, Soreq et.al ’16, Yu ’16, Carpenter et.al ’16] Matthias Schlaffer 4

Brute force method Alternative ansatz: > FCC-ee will produce 10 6 Higgses via e − Z Z ∗ e + h > O (200) of which decay into strange quarks > tag strange jets > Done before in Z → s ¯ s – Measurement of the strange quark forward backward asymmetry around the Z0 peak [DELPHI Collaboration, Eur.Phys.J. C14 (2000)] – Light quark fragmentation in polarized Z0 decays [SLD Collaboration, Nucl.Phys.Proc.Suppl. 96 (2001)] Matthias Schlaffer 5

Jet-Flavor > define flavor of jet for light quarks and gluon > strange quarks fragment more likely into hard kaons 10 0 10 1 F s + ( z ) Q 2 = m 2 h + K + 10 2 JAM17 Pythia 8 Herwig MG5aMC@NLO + Pythia 8 10 3 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 z Matthias Schlaffer 6

Jet-Flavor > define flavor of jet for light quarks and gluon > strange quarks fragment more likely into hard kaons 10 0 Q 2 = m 2 h + K + Pythia 8 Herwig 10 1 F g ( z ) 10 2 10 3 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 z Matthias Schlaffer 7

Jet-Flavor > define flavor of jet for light quarks and gluon > strange quarks fragment more likely into hard kaons π − π + K + � H ∈ j � p H · ˆ sR H J F = � H ∈ j � p H · ˆ s Matthias Schlaffer 8

Jet-Flavor > define flavor of jet for light quarks and gluon > strange quarks fragment more likely into hard kaons K − K + K + � H ∈ j � p H · ˆ sR H J F = � H ∈ j � p H · ˆ s Matthias Schlaffer 8

Jet-Flavor > define flavor of jet for light quarks and gluon > strange quarks fragment more likely into hard kaons > J s : R K ± = ∓ 1 , R K s = ± 1 minimizing J s , else 0 > counts collinear hard strange content > not safe against collinear emission h → u ¯ u h → d ¯ d 10 1 h → s ¯ s h → gg fraction of events / 0.02 Herwig Pythia 8 10 0 10 − 1 0 . 00 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 0 . 30 0 . 35 0 . 40 J s Matthias Schlaffer 9

Reject heavy flavor > Minimalistic approach: Just cut on largest impact parameter > Require p lab > 5 GeV ⇒ ∆ d 0 � 10 µ m > Smear truth values > Include 5 µ m uncertainty on IP h → u ¯ u h → d ¯ d 0 . 08 h → c ¯ c h → s ¯ s fraction of events / 0 . 5 µ m h → b ¯ b 0 . 06 h → gg W → had. Herwig Pythia 8 0 . 04 0 . 02 0 . 00 0 . 0 2 . 5 5 . 0 7 . 5 10 . 0 12 . 5 15 . 0 17 . 5 20 . 0 d 0 [ µ m] Matthias Schlaffer 10

Setup and assumptions h → jj data ⇒ kinematic separation s -tagger ⇒ limit other bkg cut&count, BDT,...

Setup and assumptions h → jj data ⇒ kinematic separation s -tagger ⇒ limit other bkg cut&count, BDT,... Part I: > Clean sample with hadronic Higgses > Only background other Higgs decays ( h → gg , bb , cc ) > We know which jets originate from the Higgs decay > Generate and shower with PYTHIA and Herwig > No detector simulation Matthias Schlaffer 11

σ Kaon reconstruction Charged kaons: > stable on detector scales > tracking efficiency 95% > Particle ID π ± K ± 2 σ bench marks e.g.: > no ID > ǫ K = 95% ǫ π = 12% some observable Matthias Schlaffer 12

σ Kaon reconstruction Charged kaons: > stable on detector scales > tracking efficiency 95% > Particle ID π ± K ± 3.0 2.5 2 σ bench marks e.g.: dE / dx resolution 2.0 > no ID 10 % 1.5 7 % > ǫ K = 95% 6 % ǫ π = 12% 1.0 5 % 0.5 4 % some observable 0.0 0.1 0.5 1 5 10 50 100 p [ GeV ] Matthias Schlaffer 12

σ Kaon reconstruction Charged kaons: > stable on detector scales > tracking efficiency 95% > Particle ID π ± K ± 3.0 2.5 2 σ bench marks e.g.: dE / dx resolution 2.0 > no ID 10 % 1.5 7 % [1811.10545] > ǫ K = 95% 6 % ǫ π = 12% 1.0 5 % 0.5 4 % some observable 0.0 0.1 0.5 1 5 10 50 100 p [ GeV ] Matthias Schlaffer 12

σ Kaon reconstruction Charged kaons: > stable on detector scales > tracking efficiency 95% > Particle ID IDEA Drift chamber Par7cle"Separa7on"(dE/dx"vs"dN/dx)" π ± K ± 3.0 10" #"of"sigma" µ- π π - Κ Κ -p 2.5 9" 2 σ bench marks e.g.: 8" dE / dx resolution 2.0 > no ID 10 % 7" 1.5 7 % 6" [1811.10545] > ǫ K = 95% 5" 6 % ǫ π = 12% 1.0 4" 5 % 0.5 4 % 3" some observable 2" 0.0 0.1 0.5 1 5 10 50 100 1" p [ GeV ] 0" 0.1" 1" 10" 100" Momentum"[GeV/c]" [FCC-ee CDR] Matthias Schlaffer 12

Kaon reconstruction Neutral kaons: > Decay length ∼ 80 cm > Needs to decay to π ± within 5 mm < R < 1 m > reco efficiency 80% Matthias Schlaffer 13

Efficiencies > impact parameter d 0 < 15 µ m no particle ID 10 − 1 10 − 2 h → u ¯ u ǫ h → d ¯ d h → c ¯ c 10 − 3 h → s ¯ s h → b ¯ b h → gg W → had. Herwig 10 − 4 Pythia 8 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 J s Matthias Schlaffer 14

Efficiencies > impact parameter d 0 < 15 µ m with particle ID: ǫ K = 95% , ǫ π = 12% 10 − 1 10 − 2 h → u ¯ u ǫ h → d ¯ d 10 − 3 h → c ¯ c h → s ¯ s h → b ¯ b h → gg 10 − 4 W → had. Herwig Pythia 8 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 J s Matthias Schlaffer 14

Number of events > impact parameter d 0 < 15 µ m no particle ID 10 − 2 10 − 3 h → u ¯ u 10 − 4 h → d ¯ d h → c ¯ c 10 − 5 BR · ǫ h → s ¯ s h → b ¯ b 10 − 6 h → gg Herwig 10 − 7 Pythia 8 10 − 8 10 − 9 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 J s Matthias Schlaffer 15

Number of events > impact parameter d 0 < 15 µ m with particle ID: ǫ K = 95% , ǫ π = 12% 10 − 2 10 − 3 h → u ¯ u 10 − 4 h → d ¯ d 10 − 5 h → c ¯ c BR · ǫ h → s ¯ s 10 − 6 h → b ¯ b h → gg 10 − 7 Herwig Pythia 8 10 − 8 10 − 9 10 − 10 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 J s Matthias Schlaffer 15

Results part I d 0 = 0 . 015 mm, ǫ K ± = 0 . 88 d 0 = 0 . 013 mm, ǫ K ± = 0 . 92 1 . 8 Herwig Pythia 8 1 . 6 1 . 4 B √ 1 . 2 S/ 1 . 0 N Higgs = 10 7 0 . 8 0 . 6 0 . 05 0 . 10 0 . 15 0 . 20 0 . 25 J s > strange Yukawa within reach of FCC-ee! > Improvements possible Matthias Schlaffer 16