Diapositiva 1

1
fermion and sfermion masses
Melina Gómez Bock
Mini-Workshop on flavor physics Mexican taste
24-25 November 2008
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flavor history
...el sabor leptónico nació con el descubrimiento
del muón y la famosa pregunta de I.I. Rabi
quién ordenó esto? W. Marciano97
Light!
Una vez que Gell-Mann y yo ibamos camino a un
restaurant en Pasadena para comer, pasamos por un
lugar de helados Baskin Robins, donde
anunciaban 32 sabores diferentes. De repente, a
Murray se le ocurrio una propuesta para usar el
término sabor" (...) para distinguir entre los
diferentes grados de libertad de los
quarks.Fritzsch01
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contents

• SUSY
• Flavor in SUSY
• Sfermions masses
• Radiative generation of lepton masses
• Flavor violation processes

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Planck Scale
E
1019GeV
10-33cm
10-44s
GU
FV
SUSY
FCNC
EW
246 MeV
Standard Model
EM
weak
x
t
strong
gravity
1GeV 1.2 13 K
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Susy
Q
fermions
bosons
Q gt gt
Q gt gt
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Chiral supermultiplet
Fermión de Weyl
Campo escalar complejo
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Flavor in SUSY
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Sfermion mass matrix
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General contributions to sfermion mass
From Soft SUSY breaking terms
Direct contribution to sfermion masses
Contribution through Higgs interaction
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Trilineal scalar couplings
Off-diagonal mass terms
trilineal mass terms
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Mass contribution from auxiliary field F
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Mass contribution from auxiliary field D
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sfermion masses
A
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Trilineal terms

• Several conditions or scenarios have been
  proposed , which reduce the number of free
  parameters and safely fit the experimental
  restrictions.

• degeneration, where different sfermion families
  have the same mass
• proportionality, here the trilinear A-terms are
  proportional to the Yukawa couplings
  (SUGRA)Hall86
• decoupling, where the superpartners are too
  heavy to affect the low energy physics(Split
  SUSY, focus point SUSY, inverted
  hierarchy)Feng05
• alignment, in this case the same physics that
  plains the fermion mass spectra and mixing angles
  also would explain the pattern of sfermions mass
  spectra Nir1993

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Trilineal term Ansatz
advantages

• We have a defined mixing angle for sfermions
• Analitic expresions for FV processes
• We have no dependence on renormalization scale Q
• We are able to compare with low scale data
• Bound the parameter space of the model
• We have expresions for mass values of different
  sfermions -gt non-universality

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LO mass matrix
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Sfermion masses
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Radiative generation of leptons masses
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Radiative generation of leptons masses
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Flavor violation
B
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Flavor violation in leptons
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sabor!!!!
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Hierarchy problem
h0
h0