ENCONTRANDO O B

1
ENCONTRANDO O BÓSON DE HIGGS ATRAVÉS DE
SUPERSIMETRIA

• Maurício B. Magro (CUFSA Santo André)F. de
  Campos (FEG / UNESP - Guaratinguetá)Oscar Éboli
  (IFUSP São Paulo)D. Restrepo (U. Antioquia -
  Colômbia)J. W. F. Valle (U. Valência - Espanha)

2
SUPERSYMMETRY AND THE HIGGS BOSON

• The CERN LHC will test the origin of mass and the
  nature of electroweak symmetry breaking ? Higgs
  Boson ? Hierarchy Problem
• Supersymmetry (SUSY) is a possible solution to
  the hierarchy problem
• Weak scale Supersymmetry breaking unifies gauge
  coupling constants and can include gravity
• SUSY is broken via SuperGravity
• ????
• New physics beyond the Standard Model

3
THE BILINEAR R-PARITY MODEL IN mAMSB

• In SUSY there is a multiplicative quantum number
  called R-parity
• RP (-1)2J3BL
• If R-parity is conserved
• 1. SUSY particles are produced in pairs.
• 2. SUSY particles must decay into antother SUSY
  particles.
• 3. There is a stable SUSY particle LSP
  (neutralino).
• We introduced a bilinear term in the SUSY
  superpotential
• eiLiHu
• that breaks R-parity explicitly.

4
Consequences

1. Only one neutrino aquires mass at tree level. The
   neutrino mass spectrum can be cosistent with
   neutrino oscillation data, favouring ?? ? ??.
2. The neutrino mass is given by with ?i
   ??i ei?d
3. The neutrino mixing angles are given by
   and
4. The lightest nuetralino is unstable, therefore
   can decay inside the present detector colliders
   ? New signatures at colliders.
5. The Neutralino branching ratio into Higgs is

5
HIGGS SEARCH

• Neutralino Decays
• It can decay through Higgs boson as
• ?0 ? ? H .? ? bb
• The model backgrounds are
• ?0 ? ? Z .? ? bb and ?0 .? ? bb
• ?0 ? tW.? ? qq (mistaged bs)

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• The LSP can live long enough to produce a
  displaced vertex at detectors.
• The displaced vertices have litte if none
  background at LHC
• We have considered a neutralino that lives long
  enough to decay out the primary vertex and before
  the tracking detectors.
• We have applied the following kinematic cuts
• 1. All charged tracks must be inside the region
  of ? lt 2.5
• 2. We considered a b-tagging efficiency of either
  50 or 30
• 3. We required an isolated electon(muon) with pt
  gt 20(6) GeV
• or a jet with pt gt 100 GeV
• or missing tranverse energy Etmiss gt 100 GeV
  
• 4. We required an invariant mass inside the range
  
• 100 GeV lt MH lt 125 GeV

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THE RESULTS

• The parameters are
• m1/2 m0 Tanß 10 sign(?) gt 0 ei ?i.
• - We have used SPheno code to calculate the
  R-Parity violating branching ratios and Pythia
  code to calculate the cross sections.
• - We required at least 5 background free events,
  consistent with neutrino data.

Reach for LHC
Reach for
Tevatron 10 fb-1 (stars) and 100 fb-1 (squares)
2 fb-1 (stars) and 8 fb-1
(squares)
8
Results
Reach for LHC
Reach for
Tevatron 10 fb-1 (stars) and 100 fb-1 (squares)
2 fb-1 (stars) and 8 fb-1
(squares)
low efficienciy

• For more details, see Phys. Rev. D80, 015002
  (2009).