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 H [GeV] 3 10 2 10 10 LHC HIGGS XS WG 2010 1.0 0.8 h! f f 1 0.6 Br -1 10 0.4-2 10 100 200 300 500 1000 M H [GeV] 0.2 0.0 h! VV h! VV h(125 GeV) = 4.1 MeV
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 1 0.1 z = m s 2 ëv 2 z = 0.01 Br HhÆssL k 0.01 0.001 z = 0.001 z = 0.005 Simple example: one new scalar L = 2 s2 H 2 10-4 0 10 20 30 40 50 60 m s HGeVL
A light SM-like Higgs is narrow Exotic Higgs decay modes easily sensitive to new physics scales significantly above a TeV 1.0 0.8 M = 2.5 TeV M = 1 TeV Simple dim-5 interaction L = 1 M H 2 Br HhÆccL k 0.6 0.4 0.2 M = 5 TeV M = 10 TeV M = 20 TeV 0.0 0 10 20 30 40 50 60 m cq HGeVL
Exotic Higgs Decays at the LHC Higgs production in gluon fusion (8 TeV): 20 pb Accumulated data at 8 TeV: 20 ifb ~400,000 Higgs bosons served If: order one acceptance, good S/B: statistics for branching fractions ~10-4
Exotic Higgs Decays at the LHC κ g 2.0 1.5 1.0 0.5-1 -1 CMS Preliminary s = 7 TeV, L 5.1 fb s = 8 TeV, L 12.2 fb 0.0 0.0 0.5 1.0 BR BSM 20 18 16 14 12 10 8 6 4 2 0-2 Δ ln L CMS indirect limits on BSM Higgs width
Exotic Higgs Decays at the LHC Unofficial combination of ATLAS and CMS (Giardino et al.); (see also Ellis, You; Belanger et al.)
Exotic Higgs Decays at the LHC A tough signal for a hadron machine like LHC: (pp H+X) [pb] 10 1-1 10 pp 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) s= 7 TeV LHC HIGGS XS WG 2010 h a a b b b b -2 10 100 200 300 400 500 1000 M H [GeV] Four soft b-jets: p T. 30 GeV...but also, many searches have not yet been done
Immense landscape of possibilities Higgs portal couplings: L int = X i 1 d i 2 i H 2 O (d i) i +... Signatures depend on how HS states decay: to further HS states, back to SM May be: NMSSM-like, semi-invisible, high multiplicity, displaced,... Exotic Decays of the 125 GeV Higgs Boson, arxiv:1312.4992 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
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?
Theories for Exotic Higgs Decays 1. Higgs decay to scalars h a a b f f f b b BR 1 0.1 0.01 bb cc ss ΤΤ ΜΜ gg f b 0.001 ΓΓ uu dd L = V (a)+ a 2 H 2 4 10 4 1 2 5 10 20 50 m s GeV Singlet Br: SM Yukawas
Theories for Exotic Higgs Decays 1. Higgs decay to scalars h a a b f f f f b b b BR h ss XXYY 1 0.1 0.01 4b bbττ ccττ 4Τ 4g ggττ bbμμ 4Μ ΤΤΜΜ ggμμ 0.001 L = V (a)+ 4 a 2 H 2 10 4 1 2 5 10 20 50 m s GeV Singlet pair Br: SM Yukawas
Theories for Exotic Higgs Decays 1. Higgs decay to scalars Type I Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S BR 1 0.1 0.01 bb cc ss ΤΤ ΜΜ gg Type 1: SM 0.001 uu dd ΓΓ 10 4 1 2 5 10 20 50 m a GeV Singlet pseudoscalar Br: SM Yukawas
Theories for Exotic Higgs Decays 1. Higgs decay to scalars Tan Β 5, TYPE II Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S BR 1 0.1 0.01 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like 0.001 uu dd ΓΓ 10 4 1 2 5 10 20 50 m a GeV Singlet pseudoscalar Br: Type II Yukawas
Theories for Exotic Higgs Decays 1. Higgs decay to scalars Tan Β 5, TYPE III Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S BR 1 0.1 0.01 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like Type III: lepton-specific 0.001 uu dd ΓΓ 10 4 1 2 5 10 20 50 m a GeV Singlet pseudoscalar Br: Type III Yukawas
Theories for Exotic Higgs Decays 1. Higgs decay to scalars Tan Β 5, TYPE IV Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S BR 1 0.1 0.01 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like Type III: lepton-specific Type IV: flipped 0.001 uu dd ΓΓ 10 4 1 2 5 10 20 50 m a GeV Singlet pseudoscalar Br: Type IV Yukawas
Theories for Exotic Higgs Decays 2. Higgs decay to fermions Lepton number violation Nonrenormalizable L = HL L = 1 M H 2 1 0.1 L = 0.5 TeV Br HhÆyyL k 0.01 0.001 10-4 L = 1 TeV L = 2 TeV Chiral symmetry: can be effective dim-6 10-5 10-6 0 10 20 30 40 50 60 m y HGeVL
Theories for Exotic Higgs Decays 2. Higgs decay to fermions X Signatures depend on further fermion couplings: parameters largely independent of Higgs couplings h X invisible: DM, SUSY h h h light bosonic dofs? flavored 3-body decays
Theories for Exotic Higgs Decays 3. Higgs decay to vectors h L = V (S)+ apple 4 S2 H 2 Photon and Higgs portal couplings with independent strengths Higgs mixing: h! V D V D, h! aa Kinetic mixing: h! V D Z + B µ V µ
Theories for Exotic Higgs Decays 3. Higgs decay to vectors 0.5 0.4 Br 0.3 light hadrons 0.2 0.1 0.0 cc Τ Τ bb ΝΝ 10 20 30 40 50 60 m ZD Relatively leptophilic!
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
Direct searches for exotic Higgs decays Example 1:. h! V D V D! 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
Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` 60 50 m V = 20 GeV s max = 7.3 fb m 2 HGeVL 40 30 20 10 40 60 80 100 m 1 HGeVL CMS data, SM background: ZZ* Exotic contribution
Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` 60 50 m V = 40 GeV s max = 3.4 fb m 2 HGeVL 40 30 20 10 40 60 80 100 m 1 HGeVL CMS data, SM background: ZZ* Exotic contribution
Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` 0.0010 Br k HhÆ ZDZDL 0.0008 0.0006 0.0004 0.0002 ATLAS ZZ control region CMS Higgs 0.0000 10 20 30 40 50 60 m ZDq HGeVL 95% CL limits
Direct searches for exotic Higgs decays Example 1A: h! ZV D! 4`. Br h ZX Br X 10 4 15 10 5 0 ATLAS 20 5fb 1 CMS 20 5fb 1 15 20 25 30 m X 95% CL limits
Direct searches for exotic Higgs decays Example 1A:. h! ZV D! 4` 10-1 CMS EWPM 10-3 10-2 a m, 5 s WASA KLOE BaBar 10-4 10-5 BrHhÆZZ D L=10-6 Further possibilities: e 10-3 E774 a m,±2 s favored a e APEXêMAMI h! ss! 4Z D h! Z D Z D! exotic 10-4 E141 PROMPT more complicated HS cascades... 10-5 NON-PROMPT Orsay U70 10-3 10-2 10-1 1 10 1 m ZD @GeVD
Direct searches for exotic Higgs decays Example 2: h! aa! 4, 2 2µ. Exclusions from multilepton searches
Direct searches for exotic Higgs decays Example 2: h! aa! 4, 2 2µ. Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]
Direct searches for exotic Higgs decays Example 2A: h! 2 2! 4`+ MET Best existing limits from inclusive many-bin CMS multi-lepton searches: Br(h! 2 2 ) < 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
Direct searches for exotic Higgs decays Example 2B: h! 2 2! 2 + MET GMSB neutralinos extended DM sector with dipole 1.00 0.50 Estimated 95% CL limits on allowed Br 40 GeV 50 GeV h Allowed BR 0.20 0.10 0.05 20 GeV 30 GeV 0.02 60 GeV 0 10 20 30 40 50 m c1 Best limits: GMSB search (CMS SUS-12-018) 4 ifb, not optimized for Higgs signal
Direct searches for exotic Higgs decays Example 3:. h! ss! 2b2µ 2m 2 µ 3m 2 b =4 10 4 Max. Br h aa bbμ Μ 1 10 1 10 2 10 3 8TeVLHC,L 25 fb 1 10 4 10 20 30 40 50 60 m a GeV No b tag Two b tags At least one b tag Estimated 95% CL reach
Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.
Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.
Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.
Summary and Conclusions 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 but reduced acceptance for low-pt objects may limit reach Important to remember for LHC 14: many physics Great statistical power from LHC 14: Higgs factory opportunities at low pt