RGE behavior of SUSY with a U (2) 3 symmetry

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Regular Article - Theoretical Physics

RGE behavior of SUSY with a U (2)3 symmetry Gianluca Blankenburg1 , Joel Jones-Pérez2,3,4,a 1

Dipartimento di Fisica, Università di Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati, Italy 3 Departament de Física Teòrica and IFIC, Universitat de València-CSIC, 46100, Burjassot, Spain 4 Theory Division, CERN, 1211 Geneva 23, Switzerland 2

Received: 25 October 2012 / Revised: 12 December 2012 / Published online: 1 February 2013 © Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica 2013

Abstract The first LHC results seem to disfavor, from the point of view of naturalness, any constrained MSSM realization with universal conditions at the SUSY-breaking scale. A more motivated scenario is given by split-family SUSY, in which the first two generations of squarks are heavy, compatible with a U (2)3 flavor symmetry. We consider this flavor symmetry to be broken at a very high scale and study the consequences at low energies through its RGE evolution. Initial conditions compatible with a split scenario are found, and the preservation of correlations from minimal U (2)3 breaking are checked. The various chiral operators in F = 2 processes are analyzed, and we show that, due to LHC gluino bounds, the (LL)(RR) operators cannot always be neglected. Finally, we also study a possible extension of the U (2)3 model compatible with the lepton sector.

1 Introduction In the past years, weak scale supersymmetry (SUSY) has possibly been the best motivated paradigm as an extension for the Standard Model (SM). The most popular realization of SUSY has been the Minimal Supersymmetric Standard Model (MSSM), usually studied through its constrained form, the CMSSM. Based on models of gravity mediated SUSY-breaking, the CMSSM has only a few additional parameters, defined at a unification scale, MGUT . The parameters of the model would then be evolved down to a SUSY-decoupling scale, MSUSY , through the use of renormalization group equations (RGE). One of the main consequences of this approach is that the soft SUSY-breaking terms would acquire a flavor structure compatible with the Minimal Flavor Violation (MFV) ansatz [1]. The current lack of SUSY signals at the LHC have forced the theoretical community to start stepping way from this

simple realization of SUSY, and consider more complex scenarios that could still preserve all of its virtues, but at the same time avoid the current experimental constraints. One such scenario is that of hierarchical soft sfermion masses [2–7], where the first two generations are heavy enough to avoid the current bounds, but the third generation is light enough to mitigate the naturalness problem, and still give us a chance to observe a signal in the near future. Given such a scenario, one can question if a MFV flavor structure is as well motivated as in the CMSSM. In fact, it is difficult for MFV to provide such a split layout, especially for very hierarchical masses. Thus, it is