Alexander Belyaev 1

"Implications of the 4-muon signature in the NMSSM"”

Alexander Belyaev

Southampton University & Rutherford Appleton LAB

Implications of the 4-muon signature in the NMSSM

Dark Matter motivated SUSY collider signatures

NMSSM Workshop, November 16-17, 2009, LPT, d’Orsay

In collaboration with Jim Pivarski, Alexei Safonov and Sergey Senkin

Texas A&M University [work in progress]

Alexander Belyaev 2

"Implications of the 4-muon signature in the NMSSM"”

NMSSMNilles, Srednicki, Wyler, Frere, Jones Raby, Ellis, Gunion, Haber, Roszkowski, Zwirner, Drees,

Ellwanger, Rausch, Savoy, Elliott, King, White, Pandita, Ellwanger, Franke, Fraas, Kim

provides an elegant solution to -problem of MSSM

with

NMSSM solves little hierarchy problem of MSSM

“singlino” can play a role of successful DM candidate

rich collider phenomenology, rises no-loose problem/theorem

is replaced with

Alexander Belyaev 3

"Implications of the 4-muon signature in the NMSSM"”

Motivation for pp->h1->a

1a

1->4 signature search

ma1

< 2 mhas not been explored

previously studied: h1 -> a1a

1 -> 4 when 2m < m

a1 < 2m

b

[see Stefano Moretti’s talk]

pp->h1->a

1a

1->4provides with a clean signature of two pairs of

collimated muons

could be a near zero background early LHC search

lack of missing energy allows direct measurement of ma1

, mh1

two tightly-collimated + - pairs leading pT > 20 GeV: negligible background from J/

Alexander Belyaev 4

"Implications of the 4-muon signature in the NMSSM"”

Recent results from D0 on pp->h1->a

1a

1->4 search

Phys.Rev.Lett.103:061801,2009

gg->h1 was assumed to be SM like!

Alexander Belyaev 5

"Implications of the 4-muon signature in the NMSSM"”

TOOLS for production cross sectionNMSSMTOOLS: mass spectra, Br, reduced couplings for NMSSM Higgs

21 ))(()(

1

NMSSMbbh

SMNMSSM GHbbhbb →=→ σσ

( )SM

ggH

NMSSMgghSMNMSSM Hgghgg

→

→

ΓΓ

→=→ 1)(1 σσ

SMggH

NMSSMtotalhSM gghBr

Hgg→Γ

Γ→→= 1

)()( 1σ

SMggH

SMSM HbbHgg →Γ→→ ),(),( σσ

NMSSMbbh

NMSSMtotalh GgghBr

11,),( 1 Γ→

HIGLU, HDECAY: NLO cs, Br, partial width for SM Higgs

Production cross section can be expressed using information above

*

*

[Ulrich Ellwanger, Cyril Hugonie]

[Djouadi,Kalinowski,Spira]

Alexander Belyaev 6

"Implications of the 4-muon signature in the NMSSM"”

MC generators/ME generators

PYTHIA was used in this study with CMS detector parameters from CMS TDR

Recent CalcHEP development allows now to generate events for the whole chain (see talk by Sasha Pukhov)

NMSSM model is in CalcHEP

ggH and H effective vertices are added

User friendly GUI interfacebatch interface – production and decay are in one chain nowcan cross check results in two gaugesOne can implement further modifications of NMSSM using superpotential formalism thought the LanHEP package (one can also use Feynrules, see talks by Benjamin Fuks and by Felix Braam)

Alexander Belyaev 7

"Implications of the 4-muon signature in the NMSSM"”

NMSSM parameter space

superpotentialSoft-breaking

terms

Alexander Belyaev 8

"Implications of the 4-muon signature in the NMSSM"”

NMSSM parameter spacerates and Br are defined by singlet/non-singlet components of h

1 and a

1

a1 is essentially singlet over the entire space including the Peccei-Quinn (k->0) or

R-symmetry limit (A, A -> 0). For example, for A, A -> 0, non-singlet component

is defined by which is small

Alexander Belyaev 9

"Implications of the 4-muon signature in the NMSSM"”

h1 couplings to SM fermions and gauge bosons

also controls the singlet/non-singlet admixture of h1

and its couplings to fermions and gauge bosons

Alexander Belyaev 10

"Implications of the 4-muon signature in the NMSSM"”

Br(a1 -> 2

Alexander Belyaev 11

"Implications of the 4-muon signature in the NMSSM"”

gg->h1 / bb ->h

1 production cross section

Alexander Belyaev 12

"Implications of the 4-muon signature in the NMSSM"”

Parametrer space with constraints

Alexander Belyaev 13

"Implications of the 4-muon signature in the NMSSM"”

Parametrer space with constraints

Alexander Belyaev 14

"Implications of the 4-muon signature in the NMSSM"”

Parametrer space with constraints

is this physical region?

Alexander Belyaev 15

"Implications of the 4-muon signature in the NMSSM"”

pp->h1->a

1a

1->4 signal acceptance study at the LHC

CMS as a benchmarkFiner granularity in muon identication than D0: require 4 muons

highest pT > 20 GeV, all others > 5 GeV

< 2.4

minimize R(1, 2)2 + R(3, 4)2 to pair 1-2 and 3-4

simultaneously fit m12

, m34

, and m1234

spectra: background is mostly smooth function while signal has narrow 3D bump in (m12 , m34 , m1234)

simulated distributions with detector resolution (CMS TDR)

Alexander Belyaev 16

"Implications of the 4-muon signature in the NMSSM"”

Background processes

Electroweak pp->4l: CalcHEP: NegligibleQCD:

2->2 Pythia ● Leptons from heavy flavor,

including J/psi

Direct J/psi+X production (also Pythia): negligible

Fakes from QCD with misidentified muons

● Use 2->2 Pythia with 3 leptons+track smearing with decay probabilities

Alexander Belyaev 17

"Implications of the 4-muon signature in the NMSSM"”

Signal acceptance and cross section limits

Alexander Belyaev 18

"Implications of the 4-muon signature in the NMSSM"”

Tevatron versus LHC reach

Alexander Belyaev 19

"Implications of the 4-muon signature in the NMSSM"”

Tevatron versus LHC reach

Alexander Belyaev 20

"Implications of the 4-muon signature in the NMSSM"”

Tevatron versus LHC reach

Alexander Belyaev 21

"Implications of the 4-muon signature in the NMSSM"”

Conclusions

pp->h1->a

1a

1->4 is a sensitive discovery mode for ma < 2m

D0 search doesn't rule out the large parameter space, SM cs is assumed there, while the NMSSM production CS is suppressed

CMS muon spectrometer allows for identication of all four muons, providing clean signature and significant reach

a1 is essentially signlet, BBAR and CLEO do not exclude light

singlet a1, whose coupling to fermions and gauges bosons

highly suppressed