Looking through the Higgs portal with exotic Higgs decays

Transcription

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

2 A light SM-like Higgs is narrow H [GeV] LHC HIGGS XS WG h! f f Br M H [GeV] h! VV h! VV h(125 GeV) = 4.1 MeV

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 z = m s 2 ëv 2 z = 0.01 Br HhÆssL k z = z = Simple example: one new scalar L = 2 s2 H m s HGeVL

4 A light SM-like Higgs is narrow Exotic Higgs decay modes easily sensitive to new physics scales significantly above a TeV M = 2.5 TeV M = 1 TeV Simple dim-5 interaction L = 1 M H 2 Br HhÆccL k M = 5 TeV M = 10 TeV M = 20 TeV m cq HGeVL

5 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

6 Exotic Higgs Decays at the LHC κ g CMS Preliminary s = 7 TeV, L 5.1 fb s = 8 TeV, L 12.2 fb BR BSM Δ ln L CMS indirect limits on BSM Higgs width

7 Exotic Higgs Decays at the LHC Unofficial combination of ATLAS and CMS (Giardino et al.); (see also Ellis, You; Belanger et al.)

8 Exotic Higgs Decays at the LHC A tough signal for a hadron machine like LHC: (pp H+X) [pb] 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 M H [GeV] Four soft b-jets: p T. 30 GeV...but also, many searches have not yet been done

9 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: 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

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?

11 Theories for Exotic Higgs Decays 1. Higgs decay to scalars h a a b f f f b b BR bb cc ss ΤΤ ΜΜ gg f b ΓΓ uu dd L = V (a)+ a 2 H m s GeV Singlet Br: SM Yukawas

12 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 b bbττ ccττ 4Τ 4g ggττ bbμμ 4Μ ΤΤΜΜ ggμμ L = V (a)+ 4 a 2 H m s GeV Singlet pair Br: SM Yukawas

13 Theories for Exotic Higgs Decays 1. Higgs decay to scalars Type I Extended Higgs sectors alter Yukawas: consider 2HDM + complex singlet S BR bb cc ss ΤΤ ΜΜ gg Type 1: SM uu dd ΓΓ m a GeV Singlet pseudoscalar Br: SM Yukawas

14 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 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like uu dd ΓΓ m a GeV Singlet pseudoscalar Br: Type II Yukawas

15 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 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like Type III: lepton-specific uu dd ΓΓ m a GeV Singlet pseudoscalar Br: Type III Yukawas

16 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 bb cc ss ΤΤ ΜΜ gg Type 1: SM Type II: NMSSM-like Type III: lepton-specific Type IV: flipped uu dd ΓΓ m a GeV Singlet pseudoscalar Br: Type IV Yukawas

17 Theories for Exotic Higgs Decays 2. Higgs decay to fermions Lepton number violation Nonrenormalizable L = HL L = 1 M H L = 0.5 TeV Br HhÆyyL k L = 1 TeV L = 2 TeV Chiral symmetry: can be effective dim m y HGeVL

18 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

19 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

20 Theories for Exotic Higgs Decays 3. Higgs decay to vectors Br 0.3 light hadrons cc Τ Τ bb ΝΝ m ZD Relatively leptophilic!

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

22 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

23 Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` m V = 20 GeV s max = 7.3 fb m 2 HGeVL m 1 HGeVL CMS data, SM background: ZZ* Exotic contribution

24 Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` m V = 40 GeV s max = 3.4 fb m 2 HGeVL m 1 HGeVL CMS data, SM background: ZZ* Exotic contribution

25 Direct searches for exotic Higgs decays Example 1:. h! V D V D! 4` Br k HhÆ ZDZDL ATLAS ZZ control region CMS Higgs m ZDq HGeVL 95% CL limits

26 Direct searches for exotic Higgs decays Example 1A: h! ZV D! 4`. Br h ZX Br X ATLAS 20 5fb 1 CMS 20 5fb m X 95% CL limits

27 Direct searches for exotic Higgs decays Example 1A:. h! ZV D! 4` 10-1 CMS EWPM a m, 5 s WASA KLOE BaBar 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 NON-PROMPT Orsay U m

28 Direct searches for exotic Higgs decays Example 2: h! aa! 4, 2 2µ. Exclusions from multilepton searches

29 Direct searches for exotic Higgs decays Example 2: h! aa! 4, 2 2µ. Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]

30 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 , SUS ) (includes Z Br and is highly spectrum-dependent) Most multi-lepton analyses specialized for high-pt signals Can further target analyses to Higgs kinematics

31 Direct searches for exotic Higgs decays Example 2B: h! 2 2! 2 + MET GMSB neutralinos extended DM sector with dipole Estimated 95% CL limits on allowed Br 40 GeV 50 GeV h Allowed BR GeV 30 GeV GeV m c1 Best limits: GMSB search (CMS SUS ) 4 ifb, not optimized for Higgs signal

32 Direct searches for exotic Higgs decays Example 3:. h! ss! 2b2µ 2m 2 µ 3m 2 b = Max. Br h aa bbμ Μ TeVLHC,L 25 fb m a GeV No b tag Two b tags At least one b tag Estimated 95% CL reach

33 Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.

34 Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.

35 Direct searches for exotic Higgs decays LHC prospects for h! ss, aa.

36 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