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Looking through the Higgs portal with exotic Higgs decays Jessie - - PowerPoint PPT Presentation

Jan 12, 2023 358 likes •732 views

Looking through the Higgs portal with exotic Higgs decays Jessie Shelton University of Illinois, Urbana-Champaign Unlocking the Higgs Portal (U. Mass. Amherst) May 1, 2014 A light SM-like Higgs is narrow 3 10 [GeV] LHC HIGGS XS WG 2010

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SLIDE 1

Looking through the Higgs portal with exotic Higgs decays

Jessie Shelton

University of Illinois, Urbana-Champaign Unlocking the Higgs Portal (U. Mass. Amherst) May 1, 2014

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SLIDE 2

0.0 0.2 0.4 0.6 0.8 1.0 Br

h → f ¯ f h → V V ∗ h → V V

[GeV]

H

M 100 200 300 1000 [GeV]

H

  • 2

10

  • 1

10 1 10

2

10

3

10

LHC HIGGS XS WG 2010

500

Γh(125 GeV) = 4.1 MeV

A light SM-like Higgs is narrow

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SLIDE 3

A light SM-like Higgs is narrow

  • Presence of new light degrees of freedom can distort

Higgs Brs by O(1) even for small couplings

Simple example: one new scalar

z = 0.001 z = 0.005 z = 0.01 z = ms2ëv2

10 20 30 40 50 60 10-4 0.001 0.01 0.1 1 ms HGeVL Br HhÆssLk

∆L = ζ 2s2|H|2

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SLIDE 4

A light SM-like Higgs is narrow

Simple dim-5 interaction

  • Exotic Higgs decay modes easily sensitive to new

physics scales significantly above a TeV

M = 1 TeV M = 2.5 TeV M = 5 TeV M = 10 TeV M = 20 TeV

10 20 30 40 50 60 0.0 0.2 0.4 0.6 0.8 1.0 mcqHGeVL Br HhÆccLk

∆L = 1 M ¯ ψψ|H|2

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SLIDE 5

Exotic Higgs Decays at the LHC

Higgs production in gluon fusion (8 TeV): 20 pb Accumulated data at 8 TeV: 20 ifb If: order one acceptance, good S/B: statistics for branching fractions ~10-4 ~400,000 Higgs bosons served

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SLIDE 6

Exotic Higgs Decays at the LHC

BSM

BR

0.0 0.5 1.0

g

κ

0.0 0.5 1.0 1.5 2.0

ln L Δ

  • 2

2 4 6 8 10 12 14 16 18 20

CMS Preliminary

  • 1

12.2 fb ≤ = 8 TeV, L s

  • 1

5.1 fb ≤ = 7 TeV, L s

CMS indirect limits on BSM Higgs width

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SLIDE 7

Exotic Higgs Decays at the LHC

Unofficial combination of ATLAS and CMS (Giardino et al.); (see also Ellis, You; Belanger et al.)

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SLIDE 8

h a b b b b a

Four soft b-jets: pT . 30 GeV A tough signal for a hadron machine like LHC: ...but also, many searches have not yet been done

[GeV]

H

M 100 200 300 400 500 1000 H+X) [pb]

  • (pp
  • 2

10

  • 1

10 1 10 = 7 TeV s

LHC HIGGS XS WG 2010

H (NNLO+NNLL QCD + NLO EW)

  • pp

qqH (NNLO QCD + NLO EW)

  • pp

WH (NNLO QCD + NLO EW)

  • pp

ZH (NNLO QCD +NLO EW)

  • pp

ttH (NLO QCD)

  • pp

Exotic Higgs Decays at the LHC

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SLIDE 9
  • D. Curtin, R. Essig, S. Gori, P

. Jaiswal, A. Katz, T. Liu, Z. Liu, D. McKeen, JS, M. Strassler, Z. Surujon, B. Tweedie, Y-M. Zhong

Immense landscape of possibilities

Exotic Decays of the 125 GeV Higgs Boson, arXiv:1312.4992

  • Higgs portal couplings:
  • Signatures depend on how HS states decay: to

further HS states, back to SM

  • May be: NMSSM-like, semi-invisible, high

multiplicity, displaced, ... Lint = X

i

1 Λdi−2

i

|H|2O(di)

i

+ . . .

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SLIDE 10

Theories for Exotic Higgs Decays

  • Long-standing body of work on

exotic Higgs decays, much driven by precision EW preference for a Higgs below the LEP bound

  • Many examples fall out naturally from extended Higgs

sectors: NMSSM, EW baryogenesis, ...

  • Others come from DM model building
  • Genericity of Higgs portal: what are light degrees of

freedom?

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SLIDE 11

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

h a b b b b a

f f f f ∆L = V (a) + λ 4 a2|H|2

1 2 5 10 20 50 104 0.001 0.01 0.1 1 msGeV BR bb cc ss ΤΤ ΜΜ gg ΓΓ uu dd

Singlet Br: SM Yukawas

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SLIDE 12

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

h a b b b b a

f f f f ∆L = V (a) + λ 4 a2|H|2

Singlet pair Br: SM Yukawas

1 2 5 10 20 50 104 0.001 0.01 0.1 1 msGeV BRhssX X YY 4b bbΤΤ ccΤΤ 4Τ 4g ggΤΤ bbΜΜ 4Μ ΤΤΜΜ ggΜΜ

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SLIDE 13

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

Singlet pseudoscalar Br: SM Yukawas

Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S Type 1: SM

1 2 5 10 20 50 104 0.001 0.01 0.1 1 maGeV BR

Type I

bb cc ss ΤΤ ΜΜ gg uu dd ΓΓ

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SLIDE 14

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

Singlet pseudoscalar Br: Type II Yukawas

Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S Type 1: SM Type II: NMSSM-like

1 2 5 10 20 50 104 0.001 0.01 0.1 1 maGeV BR

Tan Β5, TYPE II

bb cc ss ΤΤ ΜΜ gg uu dd ΓΓ

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SLIDE 15

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

Singlet pseudoscalar Br: Type III Yukawas

Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S Type 1: SM Type II: NMSSM-like Type III: lepton-specific

1 2 5 10 20 50 104 0.001 0.01 0.1 1 maGeV BR

Tan Β5, TYPE III

bb cc ss ΤΤ ΜΜ gg uu dd ΓΓ

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SLIDE 16

Theories for Exotic Higgs Decays

  • 1. Higgs decay to scalars

Singlet pseudoscalar Br: Type IV Yukawas

Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S Type 1: SM Type II: NMSSM-like Type III: lepton-specific Type IV: flipped

1 2 5 10 20 50 104 0.001 0.01 0.1 1 maGeV BR

Tan Β5, TYPE IV

bb cc ss ΤΤ ΜΜ gg uu dd ΓΓ

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SLIDE 17

Theories for Exotic Higgs Decays

  • 2. Higgs decay to fermions

∆L = λχHL ∆L = 1 M χ†χ|H|2 Lepton number violation Nonrenormalizable

L = 0.5 TeV L = 1 TeV L = 2 TeV

10 20 30 40 50 60 10-6 10-5 10-4 0.001 0.01 0.1 1 myHGeVL Br HhÆyyLk

Chiral symmetry: can be effective dim-6

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SLIDE 18

Theories for Exotic Higgs Decays

  • 2. Higgs decay to fermions

Signatures depend on further fermion couplings: parameters largely independent of Higgs couplings

h X X

h h

h

invisible: DM, SUSY light bosonic dofs? flavored 3-body decays

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SLIDE 19

Theories for Exotic Higgs Decays

  • 3. Higgs decay to vectors

h

∆L = V (S) +  4 S2|H|2 +✏BµνV µν

  • Photon and Higgs portal

couplings with independent strengths

  • Higgs mixing: ,
  • Kinetic mixing:

h → VDVD h → VDZ h → aa

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SLIDE 20

Theories for Exotic Higgs Decays

  • 3. Higgs decay to vectors
  • ΤΤ

c c b b light hadrons ΝΝ

10 20 30 40 50 60 0.0 0.1 0.2 0.3 0.4 0.5 mZD Br

Relatively leptophilic!

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SLIDE 21

Direct searches for exotic Higgs decays

  • Each final state requires its own strategy.
  • General observations:
  • Leptonic resonances especially powerful
  • Recast LHC8 analyses already place interesting limits on final

states with multiple electroweak objects

  • ...but results depend very sensitively on acceptance thresholds
  • gluon fusion: powerful but limited
  • A range of possibilities from spectacular to very

hard

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SLIDE 22

Direct searches for exotic Higgs decays

Example 1: . h → VDVD → 4`

h

Resonant 4-lepton signal: spectacular ...just need to look for it!

  • NMSSM-motivated 4-muon searches stop at 5 GeV
  • Scrape data from Higgs searches, ZZ calibration regions
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SLIDE 23

Direct searches for exotic Higgs decays

Example 1: . h → VDVD → 4`

CMS data, SM background: ZZ*

mV = 20 GeV smax = 7.3 fb

40 60 80 100 10 20 30 40 50 60 m1 HGeVL m2 HGeVL

Exotic contribution

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SLIDE 24

Direct searches for exotic Higgs decays

Example 1: . h → VDVD → 4`

CMS data, SM background: ZZ* Exotic contribution

mV = 40 GeV smax = 3.4 fb

40 60 80 100 10 20 30 40 50 60 m1 HGeVL m2 HGeVL

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SLIDE 25

Direct searches for exotic Higgs decays

Example 1: . h → VDVD → 4`

10 20 30 40 50 60 0.0000 0.0002 0.0004 0.0006 0.0008 0.0010 mZDqHGeVL BrkHhÆ ZDZDL

95% CL limits ATLAS ZZ control region CMS Higgs

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SLIDE 26

Direct searches for exotic Higgs decays

Example 1A: .

95% CL limits

h → ZVD → 4`

CMS 20 5 fb1 ATLAS 20 5 fb1

15 20 25 30 5 10 15 mX Brh Z X BrX 104

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SLIDE 27

Direct searches for exotic Higgs decays

Example 1A: . h → ZVD → 4`

10-3 10-2 10-1 1 101 10-5 10-4 10-3 10-2 10-1 mZD @GeVD e

U70

PROMPT NON-PROMPT

E141 E774 EWPM am, 5 s am,±2 s favored ae BaBar KLOE WASA APEXêMAMI Orsay BrHhÆZZDL=10-6 10-5 10-4 10-3 CMS

Further possibilities:

h → ss → 4ZD

more complicated HS cascades...

h → ZDZD → exotic

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SLIDE 28

Direct searches for exotic Higgs decays

Example 2: . h → aa → 4τ, 2τ2µ

Exclusions from multilepton searches

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SLIDE 29

Direct searches for exotic Higgs decays

Example 2: . h → aa → 4τ, 2τ2µ

Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]

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SLIDE 30

Direct searches for exotic Higgs decays

Example 2A: MET h → 22 → 4`+ Best existing limits from inclusive many-bin CMS multi-lepton searches: Br(h → χ2χ2) < 12%

(SUS-12-027, SUS-13-010) (includes Z Br and is highly spectrum-dependent)

  • Most multi-lepton analyses specialized for high-pT signals
  • Can further target analyses to Higgs kinematics
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SLIDE 31

30 GeV 40 GeV 50 GeV 60 GeV 20 GeV

10 20 30 40 50 0.02 0.05 0.10 0.20 0.50 1.00 mΧ1 Allowed BR

Estimated 95% CL limits on allowed Br

Direct searches for exotic Higgs decays

Best limits: GMSB search (CMS SUS-12-018)

  • 4 ifb, not optimized for Higgs signal

Example 2B: MET h → χ2χ2 → 2γ+

h

GMSB neutralinos extended DM sector with dipole

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SLIDE 32

Estimated 95% CL reach

Direct searches for exotic Higgs decays

Example 3: . h → ss → 2b2µ

10 20 30 40 50 60 104 103 102 101 1 ma GeV

  • Max. Br haabbΜΜ

8 TeV LHC, L25 fb1

At least one btag Two btags No btag

2m2

µ

3m2

b

= 4 × 10−4

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SLIDE 33

Direct searches for exotic Higgs decays

LHC prospects for . h → ss, aa

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SLIDE 34

Direct searches for exotic Higgs decays

LHC prospects for . h → ss, aa

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SLIDE 35

Direct searches for exotic Higgs decays

LHC prospects for . h → ss, aa

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SLIDE 36
  • The observed 125 GeV Higgs boson is highly

sensitive to the potential existence of new light degrees of freedom

  • Many interesting results/prospects at LHC8

already

  • Light (pseudo-)scalars: still difficult
  • Great statistical power from LHC 14: Higgs factory
  • but reduced acceptance for low-pT objects may limit reach
  • Important to remember for LHC 14: many physics
  • pportunities at low pT

Summary and Conclusions