[SEMINARI]: Prof. Quiros: ELECTROWEAK PHYSICS IN EXTENSIONS OF THE STANDARD MODEL WITH LARGE EXTRA DIMENSIONS

[Arcadi Santamaria Luna]

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                              S E M I N A R I

        [Image]        Departament de Física Teòrica         [Image]
                  Universitat de València - IFIC (UV-CSIC)
                      46100 Burjassot (València) Spain

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        ELECTROWEAK PHYSICS IN EXTENSIONS OF THE STANDARD MODEL WITH LARGE
                                 EXTRA DIMENSIONS

                            Prof. Mariano Quiros

                            (IEM - CSIC Madrid )

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                              Seminari del IFIC
                   Thursday 25 of May of 2000 at 12:30 AM
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                                    Resum

   We study the implications of extra dimensions of size $R\sim 1/TeV$ on
     electroweak and flavor physics due to the presence of Kaluza-Klein
 excitations of the SM gauge-bosons. We consider several scenarios with the
SM fermions either living in the bulk or being localized at different points
 of an extra dimension. Global fits to electroweak observables provide lower
bounds on 1/R, which are generically in the 2-5 TeV range. We find, however,
  certain models where the fit to electroweak observables is better than in
 the SM, because of an improvement in the prediction to the weak charge Q_W.
  We also consider the case of softly-broken supersymmetric theories and we
 find new non-decoupling effects that put new constraints on 1/R. If quarks
  of different families live in different points of the extra dimension, we
 find that the Kaluza-Klein modes of the SM gluons generate (at tree level)
 dangerous flavor and CP-violating interactions. The lower bound on 1/R can
  increase in this case up to 5000 TeV, disfavoring these scenarios in the
                          context of TeV-strings.

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