The Constrained E 6 SSM

Transcription

1 The Constrained E 6 SSM and its signatures at the LHC Work with Moretti and Nevzorov; Howl; Athron, Miller, Moretti, Nevzorov Related work: Demir, Kane, T.Wang; Langacker, Nelson; Morrissey, Wells; Bourjaily; Cvetic, Demir, Espinosa, Everett, Langacker; J.Wang; Keith, Ma; Daikoku, Suematsu; Demir, Everett; Hewett, Rizzo; Barger, Langacker, Lee, Shaughnessy, many others (apologies)

2 The problem MSSM solves technical hierarchy problem (loops) But no reason why Higgs/Higgsino mass» m soft the problem. In the NMSSM = but singlet allows SHuHd <S> Hu Hd where <S>» S 3 term required to avoid a massless axion due to global U(1) PQ symmetry S 3 breaks PQ to Z 3 resulting in cosmo domain walls (or tadpoles if broken) One solution is to forbid S 3 and gauge U(1) PQ symmetry so that the dangerous axion is eaten to form a massive Z gauge boson U(1) model Anomaly cancellation in low energy gauged U(1) models implies either extra low energy exotic matter or family-nonuniversal U(1) charges For example can have an E 6 model with three complete 7 s at the TeV scale to cancel anomalies with a U(1) broken by singlets which solve the problem This is an example of a model where Higgs triplets are not split from doublets

3 Howl, SFK Minimal E 6 SSM: Unification at M P E 6 broken via Pati-Salam chain E6 SO (1) U (1) SO (1) SU (4) SU () SU () PS L R Extra U(1) X survives to TeV scale M Planck E 6! SU(4) PS SU() L SU() R U(1) RH masses M GUT M 3 M M 1 SU(4) PS SU() L SU() R U(1)! SM U(1) X (4,,1) (4,1, ) (6,1,1) (1,,) (1,1,1) 7 Quarks, leptons Triplets and Higgs Singlet Three families of 7 s survive to low energy (minus the RH s) TeV M W U(1) X broken, Z and triplets get mass, term generated SU() L U(1) Y broken

4 Unification at M P in Minimal E 6 SSM Howl, SFK M Planck M Planck Low energy (below M GUT ) three complete families of 7 s of E 6 High energy (above M GUT» 1 16 GeV) this is embedded into a left-right symmetric Pati-Salam model and additional heavy Higgs are added.

5 E 6 SSM: Unification at M GUT E6 SO (1) U (1) Right handed neutrinos are neutral under: SO (1) SU (5) U (1) U(1) U(1) U(1) N SFK, Moretti, Nevzorov E 6 broken via SU(5) chain RH masses M GUT M 3 M M 1 E 6! SU(5) U(1) N Quarks, leptons! SM U(1) N Triplets and Higgs Singlets and RH s 7',7' H,H -bar To achieve GUT scale unification we add non-higgs TeV M W U(1) N broken, Z and triplets get mass, term generated SU() L U(1) Y broken

6 Unification at M in GUT E 6 SSM loop, 3 (M Z )=.118 Blow-up of GUT region 3 1 SFK, Moretti, Nevzorov 5 GeV 1.5 TeV 1 16 M X GeV

7 Low energy matter content of E 6 SSM s Quarks and Leptons Exotic D,D-bar 7 i. H H. Three families of Higgs Singlets Right-handed neutrinos Optional non-higgs from incomplete reps bar and doublet-triplet problems (absent in minimal E 6 SSM)

8 E 6 SSM couplings S S, u H H, H i i d i D D, D, i i F Q, L, U, D, E, N c c c c i i i i i i W SHH SDD HFF DFF Singlet-Higgs-Higgs couplings includes effective term Singlet-D-D couplings includes effective D mass terms Yukawa couplings but extra Higgs give FCNCs DQQ, DQL allows D decay but also proton decay

9 Two potential problems: rapid proton decay + FCNCs FCNC problem may be tamed by introducing a Z under which third family Higgs and singlet are even all else odd only allows Yukawa couplings involving third family Higgs and singlet H u, H d, S Z also forbids all DFF and hence forbids D decay (and p decay) Z cannot be an exact symmetry! How do we reconcile D decay with p decay? Two strategies: extra exact discrete symmetries or small D Yukawas In E 6 SSM can have extra discrete symmetries, two possibilities: I. Z L under which L are odd forbids DQL, allows DQQ exotic D are diquarks II. Z B with L & D odd forbids DQQ, allows DQL exotic D are leptoquarks Small DFF couplings <1-8 will suppress p decay sufficiently but couplings >1-1 will allow D decay with lifetime <.1 s (nucleosynth) N.B. D / g, p / g 4 (this is the only possibility in the minimal E 6 SSM) Henceforth assume problems solved by one of these approaches

10 The Constrained E 6 SSM Athron, SFK, Miller, Moretti, Nevzorov W SH H SD D i u, i d, i i i i f S H H h S H H j u, d u d, h QH t h QH b h LH t u b d d The Z allowed couplings H u, H d, S without indices are third family Higgs and singlet, H u,, H d,, S are non-higgs Assume universal soft masses m, A, M 1/ at M GUT In practice, input SUSY and exotic threshold scale S then select tan and singlet VEV <S>=s and run up third family Yukawas from S to M GUT Then choose m, A, M 1/ at M GUT and run down gauge couplings, Yukawas and soft masses to low energy and minimise Higgs potential for the 3 Higgs fields S, H u, H d (even under Z ) EWSB is not guaranteed, but remarkably there is always a solution for sufficiently large to drive m S < (c.f. large h t to drive m H < )

11 Athron, SFK, Miller, Moretti, Nevzorov tan 3, s 6 TeV,.7 P1 Consider a particular EWSB solution P1 with = -.5 P1 P1

12 Spectrum for P1 tan 3, s 6 TeV,.7,.5 M 7 GeV, m 1.6 TeV, A 1TeV 1 Athron, SFK, Miller, Moretti, Nevzorov 5TeV 4.7TeV D D 3 3.TeV 1.8TeV 1.4TeV H, h, A, h, Z 5,6 3 3,4, 1.5TeV D 1, Q, t, b, L 1.8TeV 1.7TeV non-higgs 1.4TeV t 1 46GeV 174GeV 1GeV 97GeV g, 1 h 1 1 3GeV??GeV D 1, non- Higgsinos

13 Athron, SFK, Miller, Moretti, Nevzorov tan 1, s 6 TeV,.7 Consider a particular EWSB solution P with = -.3 Expt excluded P P Theor excluded

14 Spectrum for P tan 1, s 6 TeV,.7,.3 Athron, SFK, Miller, Moretti, Nevzorov 4.9TeV 4.6TeV D 3 D 3 M 4 GeV, m TeV, A GeV 1.TeV 1.8TeV 1.TeV H, h, A, h, Z 5,6 3 3,4, 1.5TeV.TeV D 1, 1.5TeV t 1 Q, t, b, L non-higgs 3GeV 15GeV 116GeV 65GeV g h 1 1, 1 3GeV??GeV D 1, non- Higgsinos

15 Athron, SFK, Miller, Moretti, Nevzorov tan 1, s TeV, 1.8 Consider a particular EWSB solution P3 with = -.6 P3 P3

16 Spectrum for P3 tan 1, s TeV, 1.8,.6 Athron, SFK, Miller, Moretti, Nevzorov 17TeV D 3, D3 M 1 TeV, m 5.5 TeV, A 4.6TeV 1 7.5TeV 4.9TeV 3.5TeV H, h, A, h, Z 5,6 3 3,4, 4TeV 5.5TeV D 1, 4TeV t 1 Q, t, b, L non-higgs 65GeV g 3GeV D 1, 3GeV 13GeV, 1 1,h1??GeV non- Higgsinos

17 Note the characteristic spectrum For a given low energy M 1, M, M 3 need a larger M 1/ than in the MSSM Lightest states are h 1 and gauginos: Remaining gauginos, Higgs and Z are much heavier (ignoring non-higgs and non-higgsinos) Generally m >M 1/ heavy squarks,sleptons with

18 Consider the lightest gaugino states Gluino M 3.7 M 1 g» Wino M.5M 1 N, C1 1» Bino M1.15M 1 N 1 1 M 1 4 1GeV

19 Chargino and neutralino production and decay N.B. Wino production only is allowed (no Bino production via W,Z) Expect N N, N C 1, C 1 C 1 pair production (not involving the N 1» Bino ) l l l However the decays must involve N 1 N C 1 N 1 N 1

20 e.g. N N production and decay Y=N, N=N 1 pp N N V miss NN l l l l E T l ( p ) Three body m ll p p decays l ( p ) N M < M Z max m ll M M N M N 1 N 1 End point gives mass difference For absolute masses see Choi, Kim talks

21 Gluinos are light < 1 TeV and easily produced q q g N 1 m m 5 g 4 q Y g, N N 1 pp gg V gg qqqq E T miss For gluino mass see Choi, Kim talks

22 Z < 5 TeV can be discovered M g S ' Z 1 SFK,Moretti,Nevzorov

23 Exotic D-quarks D in E 6 SSM Usual case is of scalar leptoquarks, here we have novel case of D being fermonic leptoquarks or diquarks Inv. mass distribution md 3GeV Total cross section SFK,Moretti,Nevzorov SFK,Moretti,Nevzorov

24 Novel signatures of D quarks In E 6 SSM it is possible that the D fermions decay rapidly as leptoquarks or diquarks giving missing energy in the final state (Brent Nelson s talk) However it is also possible that DFF couplings are highly suppressed giving rise to long lived D quarks giving jets containing heavy long lived D-hadron D-hadrons resemble protons or neutrons but with mass >3 GeV: D Du, D Dd p n Clean events with two D-jets containing a pair of stable D-hadrons D p or D n p p D p or D n

25 Conclusions E 6 SSM s are well motivated from string theory Generally lead to lower fine tuning Unification at GUT scale or Planck scale (ME 6 SSM) ME 6 SSM solves problem without doublet-triplet splitting CE 6 SSM has successful EWSB and leads to a characteristic SUSY spectrum with light gauginos, and heavy Z D quarks can either decay promptly as fermionic leptoquarks or diquarks, or can be long lived spectacular LHC signals

26 Some details about E 6 SSM s Hypercharge Extra U(1) N surviving to TeV scale RH chargeless Most general E 6 allowed couplings from 7 3 : Optional non-higgs SHH terms SDD terms FCNC s from extra Higgs Allows p and D decay Yukawas of quarks, leptons DFF terms (F=Q,L)

27 EWSB minimisation conditions With,, s, v 1, v fixed these fix m 1, m and m s which are given by Leading to quadratic equations for m, M 1/, A with two solutions