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 1.0 2 10 H � 0.8 h → f ¯ f 10 0.6 1 Br -1 10 0.4 -2 10 h → V V ∗ 0.2 100 200 300 500 1000 h → V V M [GeV] H 0.0 Γ h (125 GeV) = 4 . 1 MeV
A light SM-like Higgs is narrow • Presence of new light degrees of freedom can distort Higgs Br s by O (1) even for small couplings 1 z = m s 2 ë v 2 z = 0.01 0.1 Simple example: one new scalar Br H h Æ ss L k 0.01 z = 0.005 ∆ L = ζ 0.001 2 s 2 | H | 2 z = 0.001 10 - 4 0 10 20 30 40 50 60 m s H GeV L
A light SM-like Higgs is narrow • Exotic Higgs decay modes easily sensitive to new physics scales significantly above a TeV 1.0 M = 1 TeV M = 2.5 TeV 0.8 M = 5 TeV Br H h Æcc L k Simple dim-5 interaction 0.6 M = 10 TeV 0.4 ∆ L = 1 ¯ ψψ | H | 2 M = 20 TeV 0.2 M 0.0 0 10 20 30 40 50 60 m c q H GeV L
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 -1 -1 CMS Preliminary s = 7 TeV, L 5.1 fb s = 8 TeV, L 12.2 fb ≤ ≤ 2.0 g ln L κ 20 18 Δ -2 16 1.5 14 12 1.0 10 8 6 0.5 4 2 0.0 0 0.0 0.5 1.0 BR BSM 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: H+X) [pb] LHC HIGGS XS WG 2010 pp � s = 7 TeV H (NNLO+NNLL QCD + NLO EW) 10 b a � pp � qqH (NNLO QCD + NLO EW) (pp b h 1 pp pp � � WH (NNLO QCD + NLO EW) ZH (NNLO QCD +NLO EW) � b pp � a ttH (NLO QCD) -1 10 b -2 10 Four soft b -jets: 100 200 300 400 500 1000 M [GeV] H p T . 30 GeV ...but also, many searches have not yet been done
Immense landscape of possibilities • Higgs portal couplings: 1 | H | 2 O ( d i ) X L int = + . . . i Λ d i − 2 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 1 f bb b cc ss ΤΤ ΜΜ gg a 0.1 f b h b f a BR 0.01 f b ΓΓ uu 0.001 dd ∆ L = V ( a ) + λ 4 a 2 | H | 2 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 1 f b 4b bb ΤΤ cc ΤΤ 4 Τ a 0.1 f 4g b h gg ΤΤ BR � h � ss � X X YY � bb ΜΜ 4 Μ b f ΤΤΜΜ a gg ΜΜ 0.01 f b 0.001 ∆ L = V ( a ) + λ 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 1 Extended Higgs sectors bb cc ss alter Yukawas: ΤΤ ΜΜ gg 0.1 consider 2HDM + complex singlet S BR 0.01 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 1 Extended Higgs sectors bb cc ss alter Yukawas: ΤΤ ΜΜ gg 0.1 consider 2HDM + complex singlet S BR 0.01 Type 1: SM 0.001 uu dd Type II: NMSSM-like 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 1 Extended Higgs sectors bb cc ss alter Yukawas: ΤΤ ΜΜ gg 0.1 consider 2HDM + complex singlet S BR 0.01 Type 1: SM 0.001 uu dd Type II: NMSSM-like ΓΓ Type III: lepton-specific 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 1 Extended Higgs sectors bb cc ss alter Yukawas: ΤΤ ΜΜ gg 0.1 consider 2HDM + complex singlet S BR 0.01 Type 1: SM 0.001 uu dd Type II: NMSSM-like ΓΓ Type III: lepton-specific 10 � 4 1 2 5 10 20 50 Type IV: flipped m a � GeV � Singlet pseudoscalar Br: Type IV Yukawas
Theories for Exotic Higgs Decays 2. Higgs decay to fermions Lepton number violation Nonrenormalizable ∆ L = 1 M χ † χ | H | 2 ∆ L = λχ HL 1 L = 0.5 TeV 0.1 0.01 L = 1 TeV Br H h Æyy L k Chiral symmetry: 0.001 L = 2 TeV can be effective dim-6 10 - 4 10 - 5 10 - 6 0 10 20 30 40 50 60 m y H GeV L
Theories for Exotic Higgs Decays 2. Higgs decay to fermions X h Signatures depend on further invisible: DM, SUSY fermion couplings: parameters largely independent of Higgs X couplings h h h light bosonic dofs? flavored 3-body decays
Theories for Exotic Higgs Decays 3. Higgs decay to vectors • Photon and Higgs portal couplings with independent h strengths • Higgs mixing: , h → V D V D h → aa • Kinetic mixing: h → V D Z ∆ L = V ( S ) + 4 S 2 | H | 2 + ✏ B µ ν V µ ν
Theories for Exotic Higgs Decays 3. Higgs decay to vectors 0.5 0.4 light hadrons 0.3 Br � � � � c c 0.2 Relatively leptophilic! 0.1 Τ � Τ � b b ΝΝ 0.0 10 20 30 40 50 60 m Z D
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 ` Resonant 4-lepton signal: spectacular h ...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 m V = 20 GeV s max = 7.3 fb 50 m 2 H GeV L 40 30 20 10 40 60 80 100 m 1 H GeV L CMS data, SM background: ZZ* Exotic contribution
Direct searches for exotic Higgs decays Example 1: . h → V D V D → 4 ` 60 m V = 40 GeV s max = 3.4 fb 50 m 2 H GeV L 40 30 20 10 40 60 80 100 m 1 H GeV L CMS data, SM background: ZZ* Exotic contribution
Direct searches for exotic Higgs decays Example 1: . h → V D V D → 4 ` 0.0010 ATLAS ZZ 0.0008 Br k H h Æ Z D Z D L control region 0.0006 0.0004 CMS Higgs 0.0002 0.0000 10 20 30 40 50 60 m Z D q H GeV L 95% CL limits
Direct searches for exotic Higgs decays Example 1A: . h → ZV D → 4 ` Br � h � Z X � � Br � X � �� � � 10 4 ATLAS 20 � 5 fb � 1 15 CMS 20 � 5 fb � 1 10 5 0 15 20 25 30 m X 95% CL limits
Direct searches for exotic Higgs decays Example 1A: . h → ZV D → 4 ` 10 - 1 CMS 10 - 3 EWPM 10 - 2 10 - 4 Further possibilities: WASA a m , 5 s BaBar KLOE 10 - 5 Br H h Æ ZZ D L = 10 - 6 h → ss → 4 Z D a m , ± 2 s favored 10 - 3 e APEX ê MAMI h → Z D Z D → exotic a e E774 more complicated HS E141 cascades... 10 - 4 PROMPT NON - PROMPT Orsay U70 10 - 5 10 - 3 10 - 2 10 - 1 1 10 1 m Z D @ GeV D
Direct searches for exotic Higgs decays Example 2: . h → aa → 4 τ , 2 τ 2 µ Exclusions from multilepton searches
Direct searches for exotic Higgs decays Example 2: . h → aa → 4 τ , 2 τ 2 µ Gain from sharp resonance in muons, despite lower BR [Lisanti & Wacker]
Direct searches for exotic Higgs decays Example 2A: MET h → � 2 � 2 → 4 ` + Best existing limits from inclusive many-bin CMS multi-lepton searches: Br ( h → χ 2 χ 2 ) < 12% (SUS-12-027, SUS-13-010) (includes Z Br and is highly spectrum-dependent) • Most multi-lepton analyses specialized for high- p T signals • Can further target analyses to Higgs kinematics
Direct searches for exotic Higgs decays Example 2B: MET h → χ 2 χ 2 → 2 γ + Estimated 95% CL limits on allowed Br GMSB neutralinos 1.00 extended DM sector with dipole 40 GeV 0.50 50 GeV Allowed BR 0.20 30 GeV 0.10 20 GeV h 0.05 60 GeV 0.02 0 10 20 30 40 50 m Χ 1 Best limits: GMSB search (CMS SUS-12-018) • 4 ifb, not optimized for Higgs signal
Recommend
More recommend
