Post on 16-Aug-2020
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
The Constrained EThe Constrained E66SSMSSMand its signatures at the LHCand 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)
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07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
�MSSM solves �technical hierarchy problem� (loops)
�But no reason why Higgs/Higgsino mass » msoft the � problem�.
�In the NMSSM =0 but singlet allows SHuHd <S> Hu Hd where <S>»
�S3 term required to avoid a massless axion due to global U(1) PQ symmetry
�S3 breaks PQ to Z3 resulting in cosmo domain walls (or tadpoles if broken)
The The problemproblem
�One solution is to forbid S3 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 E6 model with three complete 27�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
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Minimal EMinimal E66SSM: Unification at MSSM: Unification at MPPHowl, SFK
(10) (4) (2) (2)PS L RSO SU SU SU6 (10) (1)E SO U
MGUT
TeV U(1)X broken, Z� and triplets get mass, term generated
MPlanck
Quarks, leptons
Triplets and Higgs
Singlet
MW SU(2)L£ U(1)Y broken
E6! SU(4)PS£ SU(2)L £ SU(2)R
SU(4)PS£ SU(2)L £ SU(2)R £ U(1)! SM £ U(1)X
(4,2,1) (4,1,2) (6,1,1) (1,2,2) (1,1,1) 27
Three families of 27�s survive to low energy (minus the RH �s)
£ U(1)
Extra U(1)X survives to TeV scale
RH masses
M1
M2
M3
E6 broken via Pati-Salam chain
Unification at MUnification at MPP in Minimal Ein Minimal E66SSMSSM
Low energy (below MGUT) three complete families of 27�s of E6
High energy (above MGUT» 1016 GeV) this is embedded into a left-right symmetric Pati-Salam model and additional heavy Higgs are added.
Howl, SFK
MPlanck MPlanck
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
EE66SSM: Unification at MSSM: Unification at MGUTGUTSFK, Moretti, Nevzorov
15 14 4(1) (1) (1) NU U U
(10) (5) (1)SO SU U 6 (10) (1)E SO U
E6 ! SU(5)£U(1)N MGUT
TeV U(1)N broken, Z� and triplets get mass, term generated
27',27'
To achieve GUT scale unification
we add non-Higgs
Quarks, leptons
Triplets and Higgs
Singletsand RH s
H�,H�-bar
MW SU(2)L£ U(1)Y broken
Right handed neutrinos are neutral under:
! SM £ U(1)N
RH masses
M1
M2
M3
E6 broken via SU(5) chain
Unification at MUnification at MGUTGUT in Ein E66SSMSSM
3
2
1
250 GeV
1.5 TeV
Blow-up of GUT region2 loop, 3(MZ)=0.118
SFK, Moretti, Nevzorov
162 10XM
GeV
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Low energy matter content of ELow energy matter content of E66SSMSSM��s s
Exotic D,D-bar
Three families of Higgs Singlets Right-handed neutrinos
Quarks and Leptons
27i . .
Optional non-Higgs from incomplete reps 27�+27�-bar � and doublet-triplet problems (absent in minimal E6SSM)
H H
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
EE66SSM couplingsSSM couplings
SDD HSH FF D FH FW
, ,
, , , , ,
i i
c c c ci i i i i i
D D D
F Q L U D E N
,
,
i
u di i
S S
H H H
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
Two potential problems: rapid proton decay + Two potential problems: rapid proton decay + FCNCsFCNCs
� FCNC problem may be tamed by introducing a Z2 under which third family Higgs and singlet are even all else odd only allows Yukawa couplings involving third family Higgs and singlet Hu , Hd , S
� Z2 also forbids all DFF and hence forbids D decay (and p decay) Z2 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 E6SSM can have extra discrete symmetries, two possibilities:
I. Z2L under which L are odd forbids DQL, allows DQQ exotic D are diquarks
II. Z2B with L & D odd forbids DQQ, allows DQL exotic D are leptoquarks
� Small DFF couplings <10-8 will suppress p decay sufficiently but couplings >10-12 will allow D decay with lifetime <0.1 s (nucleosynth) N.B. D / g2, p / g4 (this is the only possibility in the minimal E6SSM)
Henceforth assume problems solved by one of these approachesHenceforth assume problems solved by one of these approaches
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
The Constrained EThe Constrained E66SSMSSM, ,
, ,
i u i d i i i i
j u d u d
t u b d d
W SH H SD D
f S H H h S H H
h QH t h QH b h LH
Assume universal soft masses m0, A, M1/2 at MGUT
In practice, input SUSY and exotic threshold scale S then select tan andsinglet VEV <S>=s and run up third family Yukawas from S to MGUT
Then choose m0, A, M1/2 at MGUT and run down gauge couplings, Yukawas and soft masses to low energy and minimise Higgs potential for the 3 Higgs fields S, Hu, Hd (even under Z2)
EWSB is not guaranteed, but remarkably there is always a solution for sufficiently large to drive mS
2 <0 (c.f. large ht to drive mH2<0 )
Athron, SFK, Miller, Moretti, Nevzorov
Hu, Hd, S without indices are third family Higgs and singlet, Hu,, Hd,, S are non-Higgs
The Z2 allowed couplings
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Athron, SFK, Miller, Moretti, Nevzorov
P1
P1
P1
tan 3, 6 , 0.7s TeV
Consider a particular EWSB solution P1 with = -0.5
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Spectrum for P1 Spectrum for P1
12 0700 , 1.6 , 1M GeV m TeV A TeV
1.4TeV
1.8TeV
2.2TeV
03,4 2,
02, ,H h A
0 05,6 3, ,h Z
tan 3, 6 , 0.7, 0.5s TeV
01
02 1, g
97GeV
174GeV
460GeV
01h120GeV
Athron, SFK, Miller, Moretti, Nevzorov
4.7TeV3D3D5TeV
1,2D1.5TeV
1,2D300GeV
1.4TeV 1t
2, , ,Q t b L 1.8TeV1.7TeV
non-Higgsinos
non-Higgs
??GeV
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Athron, SFK, Miller, Moretti, Nevzorov
P2 P2Expt excluded
Theor excluded
tan 10, 6 , 0.7s TeV
Consider a particular EWSB solution P2 with = -0.3
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Spectrum for P2 Spectrum for P2
12 0420 , 2 , 20M GeV m TeV A GeV
tan 10, 6 , 0.7, 0.3s TeV
Athron, SFK, Miller, Moretti, Nevzorov
1.0TeV
1.8TeV
2.2TeV
03,4 2,
02, ,H h A
0 05,6 3, ,h Z
01
02 1,
g
65GeV
125GeV
300GeV0
1h116GeV
4.6TeV3D
1.5TeV 1t
2, , ,Q t b L 2.0TeV
3D4.9TeV
1,2D1.5TeV
1,2D300GeV
non-Higgs
non-Higgsinos??GeV
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Athron, SFK, Miller, Moretti, Nevzorov
tan 10, 20 , 1.8s TeV
P3 P3
Consider a particular EWSB solution P3 with = -0.6
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Spectrum for P3 Spectrum for P3
12 01 , 5.5 , 4.6M TeV m TeV A TeV
tan 10, 20 , 1.8, 0.6s TeV
Athron, SFK, Miller, Moretti, Nevzorov
3.5TeV
4.9TeV
7.5TeV
03,4 2,
02, ,H h A
0 05,6 3, ,h Z
0 01 1,h
02 1,
g
130GeV
650GeV
230GeV
4TeV 1t
2, , ,Q t b L 5.5TeV
3 3,D D17TeV
1,2D4TeV
1,2D300GeV
non-Higgs
non-Higgsinos??GeV
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Note the characteristic spectrumNote the characteristic spectrumFor a given low energy M1, M2, M3 need a larger M1/2 than in the MSSM
Lightest states are h10 and gauginos:
Generally m0>M1/2 heavy squarks,sleptons with
2Remaining gauginos, Higgs and Z� are much heavier(ignoring non-Higgs and non-Higgsinos)
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Consider the lightest Consider the lightest gauginogaugino statesstates
01 1N
02 2 1 1,N C
g123 0.7M M
122 0.25M M
121 0.15M M
12
400 1000M GeV
» Wino
» Bino
Gluino
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
CharginoChargino and and neutralinoneutralino production and decayproduction and decay
2N
1N
l l
1C
1N
l
N.B. Wino production only is allowed (no Bino production via W,Z)
Expect N2N2 , N2C1 , C1C1 pair production (not involving the N1» Bino )
However the decays must involve N1
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
e.g. Ne.g. N22NN22 production and decay production and decay
2N
1N
( )l p
( )l p Three body decays M < MZ
22llm p p
2 1max ll N Nm M M M
End point gives mass differenceFor absolute masses see Choi, Kim talks
Y=N2, N=N1
2 2missTN N l l l l E
2 2pp N N V
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
g
1N
5
4g
q
m
m
1
,Y g
N N
pp gg V
GluinosGluinos are light < 1 are light < 1 TeVTeV and easily producedand easily produced
missTgg qqqq E
For gluino mass see Choi, Kim talks
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
'1 ZM g S
SFK,Moretti,Nevzorov
ZZ�� < 5 < 5 TeVTeV can be discovered can be discovered
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Exotic DExotic D--quarks in Equarks in E66SSMSSM
300Dm GeV
Inv. mass distribution
SFK,Moretti,Nevzorov
Total cross section
SFK,Moretti,Nevzorov
Usual case is of scalar leptoquarks, here we have novel case of D being fermonic leptoquarks or diquarks
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Novel signatures of D quarksNovel signatures of D quarksIn E6SSM it is possible that the D fermions decay rapidly as leptoquarksor 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 >300 GeV:
p p
Clean events with two D-jets containing a pair of stable D-hadrons
Dp or Dn
Dp or Dn
,p nD Du D Dd
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
ConclusionsConclusions
E6 SSM�s are well motivated from string theory
Generally lead to lower fine tuning
Unification at GUT scale or Planck scale (ME6SSM)
ME6SSM solves problem without doublet-triplet splitting
CE6SSM has successful EWSB and leads to a characteristic SUSY spectrum with light gauginos, and heavy Z�
D quarks can either decay promptly as fermionic leptoquarksor diquarks, or can be long lived spectacular LHC signals
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
Some details about ESome details about E66SSMSSM��ss
Extra U(1)Nsurviving to TeV scale
Hypercharge
Most general E6 allowed couplings from 273:
Allows p and D decay
FCNC�sfrom extra Higgs
SHH terms SDD terms
Yukawas of quarks, leptons
DFF terms (F=Q,L)
RH chargeless Optional non-Higgs
07/01/2008 Steve King, LHC New Physics Signatures Workshop, MCTP
EWSB minimisation conditions
With , , s , v1 , v2 fixed these fix m1 , m2 and ms which are given by
Leading to quadratic equations for m0 , M1/2 , A with two solutions