Publications (54)171.67 Total impact
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ABSTRACT: The recent discovery of a light CPeven Higgs in a region of masses consistent with the predictions of models with low energy supersymmetry have intensified the discussion of naturalness in these situations. The focus point solution alleviates the MSSM fine tuning problem. In a previous work, we showed the general form of the MSSM focus point solution, for different values of the messenger scale and of the ratio of gaugino and scalar masses. Here we study the possibility of inducing a light stop as a result of the renormalization group running from high energies. This scenario is highly predictive and leads to observables that may be constrained by future collider and flavor physics data.06/2014; 
Article: General Focus Point in the MSSM
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ABSTRACT: The minimal supersymmetric extension of the Standard Model (SM) is a well motivated scenario for physics beyond the SM, which allows a perturbative description of the theory up to scales of the order of the Grand Unification scale, where gauge couplings unify. The Higgs mass parameter is insensitive to the ultraviolet physics and is only sensitive to the scale of soft supersymmetry breaking parameters. Present collider bounds suggest that the characteristic values of these parameters may be significantly larger than the weak scale. Large values of the soft breaking parameters, however, induce large radiative corrections to the Higgs mass parameter and therefore the proper electroweak scale may only be obtained by a fine tuned cancellation between the square of the holomorphic \muparameter and the Higgs supersymmetry breaking square mass parameter. This can only be avoided if there is a correlation between the scalar and gaugino mass parameters, such that the Higgs supersymmetry breaking parameter remains of the order of the weak scale. The scale at which this happens is dubbed as focus point. In this article, we define the general conditions required for this to happen, for different values of the messenger scale at which supersymmetry breaking is transmitted to the observable sector, and for arbitrary boundary conditions of the sfermion, gaugino, and Higgs mass parameters. Specific supersymmetry breaking scenarios in which these correlations may occur are also discussed.02/2014;  [Show abstract] [Hide abstract]
ABSTRACT: We will explore the consequences on the electroweak breaking condition, the mass of supersymmetric partners and the scale at which supersymmetry is broken, for arbitrary values of the supersymmetric parameters tan(beta) and the stop mixing X_t, which follow from the Higgs discovery with a mass m_H\simeq 126 GeV at the LHC. Within the present uncertainty on the top quark mass we deduce that radiative breaking requires tan(beta) \gtrsim 7 for maximal mixing X_t\simeq \sqrt{6}, and tan(beta) \gtrsim 20 for small mixing X_t\lesssim 1. The scale at which supersymmetry is broken \mathcal M can be of order the unification or Planck scale only for large values of tan(beta) and negligible mixing X_t\simeq 0. On the other hand for maximal mixing and large values of tan(beta) supersymmetry should break at scales as low as \mathcal M\simeq 10^5 GeV. The uncertainty in those predictions stemming from the uncertainty in the top quark mass, i.e. the top Yukawa coupling, is small (large) for large (small) values of tan(beta). In fact for tan(beta)=1 the uncertainty on the value of \mathcal M is of several orders of magnitude.12/2013;  [Show abstract] [Hide abstract]
ABSTRACT: We study an extension of the minimal supersymmetric standard model with a zero hypercharge triplet, and the effect that such a particle has on stop decays. This model has the capability of predicting a 125.5 GeV Higgs even in the presence of light stops and it can modify the diphoton rate by means of the extra charged fermion triplet coupled to the Higgs. Working in the limit where the scalar triplet decouples, and with small values of mA, we find that the fermion triplet can greatly affect the branching ratios of the stops, even in the absence of a direct stoptriplet coupling. We compare the triplet extension with the MSSM and discuss how the additional fields affect the search for stop pair production.11/2013;  [Show abstract] [Hide abstract]
ABSTRACT: We study the implications at the LHC for the minimal (least) version of the supersymmetric standard model. In this model supersymmetry is broken by gravity and extra gauge interactions effects, providing a spectrum similar in several aspects to that in natural supersymmetric scenarios. Having the first two generations of sparticles partially decoupled means that any significant signal can only involve gauginos and the third family of sfermions. In practice, the signals are dominated by gluino production with subsequent decays into the stop sector. As we show, for gluino masses below 2300 GeV, a discovery at the LHC is possible at \sqrt{s}=14 TeV, but will require large integrated luminosities.Physical review D: Particles and fields 04/2013; 87(11).  [Show abstract] [Hide abstract]
ABSTRACT: Extending the Higgs sector of the MSSM by triplets alleviates the little hierarchy problem and naturally allows for enhancements in the diphoton decay rate of the lightest CPeven Higgs h. In the present paper we analyze in detail the Higgs phenomenology of this theory with m_h~126 GeV. We mostly focus on a light Higgs sector where the pseudoscalar A, the nexttolightest CPeven scalar H and the charged H^\pm Higgses are naturally at the electroweak scale. It turns out that for any value m_A > m_h there is a parameter region at small tan(beta) where the CPeven Higgs sector appears at colliders as the SM one, except for loopinduced corrections. Notably the existence of this SMlike point, which is absent in the MSSM, is shared with supersymmetric theories where there are extra singlets. We also highlight a second parameter region at small m_A and small tan(beta) where the h signal strengths, diphoton channel included, are SMlike except those of bottoms and taus which can have at most a 1015 % splitting. Improvements in the A and H^\pm searches are worthwhile in order to discriminate this scenario from the SM.Journal of High Energy Physics 03/2013; 2013(7). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Recent results on Higgs searches at the LHC point towards the existence of a Higgs boson with mass of about 126 GeV whose diphoton decay rate tends to be larger than in the Standard Model. These results are in tension with natural MSSM scenarios: such a Higgs mass requires heavy (thirdgeneration) squarks which reintroduce some amount of finetuning and in general the Higgs diphoton decay rate tends to follow the Standard Model result. In this paper we prove that these problems can be alleviated by introducing an extra supersymmetric triplet coupled to the Higgs in the superpotential. This superfield generates a sizeable treelevel correction to the Higgs mass so that the third generation is no longer required to be heavy, and its charged component enhances the diphoton Higgs decay rates by as much as 50% with respect to the Standard Model values. We also show that such a scenario is compatible with present electroweak precision observables.Physical review D: Particles and fields 07/2012; 86(11).  [Show abstract] [Hide abstract]
ABSTRACT: We study the implications at the LHC for a recent class of noncustodial warped extradimensional models where the AdS_5 metric is modified near the infrared brane. Such models allow for TeV KaluzaKlein excitations without conflict with electroweak precision tests. We discuss both the production of electroweak and strong KaluzaKlein gauge bosons. As we will show, only signals involving the third generation of quarks seem to be feasible in order to probe this scenario.Physical review D: Particles and fields 06/2012; 86(1).  [Show abstract] [Hide abstract]
ABSTRACT: In this paper we embed the light stop scenario, a MSSM framework which explains the baryon asymmetry of the universe through a strong first order electroweak phase transition, in a topdown approach. The required low energy spectrum consists in the light SMlike Higgs, the righthanded stop, the gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum is naturally driven by renormalization group evolution starting from a heavy scalar spectrum at high energies. The latter is obtained through a supersymmetrybreaking mix of gauge mediation, which provides the scalars masses by new gauge interactions, and gravity mediation, which generates gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\ and B_\mu\ parameters necessary for electroweak breaking and predicts small trilinear mixing terms A_t in agreement with electroweak baryogenesis requirements. The minimal embedding predicts a Higgs mass around its experimental lower bound and by a small extension higher masses m_H\lesssim 127 GeV can be accommodated.Journal of High Energy Physics 01/2012; 2012(4). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The LHC is putting bounds on the Higgs boson mass. In this Letter we use those bounds to constrain the minimal supersymmetric standard model (MSSM) parameter space using the fact that, in supersymmetry, the Higgs mass is a function of the masses of sparticles, and therefore an upper bound on the Higgs mass translates into an upper bound for the masses for superpartners. We show that, although current bounds do not constrain the MSSM parameter space from above, once the Higgs mass bound improves big regions of this parameter space will be excluded, putting upper bounds on supersymmetry (SUSY) masses. On the other hand, for the case of splitSUSY we show that, for moderate or large tanβ, the present bounds on the Higgs mass imply that the common mass for scalars cannot be greater than 10(11) GeV. We show how these bounds will evolve as LHC continues to improve the limits on the Higgs mass.Physical Review Letters 01/2012; 108(2):021802. · 7.73 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A generalization of the NexttoMinimal Supersymmetric Model (NMSSM) is studied in which an explicit \muterm as well as a small supersymmetric mass term for the singlet superfield are incorporated. We study the possibility of raising the Standard Modellike Higgs mass at tree level through its mixing with a light, mostlysinglet, CPeven scalar. We are able to generate Higgs boson masses up to 145 GeV with top squarks below 1.1 TeV and without the need to fine tune parameters in the scalar potential. This model yields light singletlike scalars and pseudoscalars passing all collider constraints.Physics Letters B 11/2011; 710(3). · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We propose the minimal (Least) version of the Supersymmetric Standard Model which can solve the hierarchy problem in the same way as the socalled Minimal Supersymmetric Standard Model (MSSM) and presents solutions to some of its problems. Supersymmetry is broken in a secluded sector and mediated to the observable sector by messengers of a gauge group G under which the first two generations transform. The group G spontaneously breaks (almost) supersymmetrically at a scale at most a few orders of magnitude below the scale of gauge messengers M_*\sim 10^{15} GeV. By gauge mediation sfermions of the first two generations acquire supersymmetry breaking masses \hat m \sim 10 TeV. Supersymmetry breaking is also mediated by gravity which generates masses for all sfermions, Higgsinos and gauginos at the TeV scale and can provide appropriate values to the \mu and B_\mu parameters by Dterm effective operators. If gravity mediation is Minimal Flavor Violating there is no supersymmetric flavor problem. In the presence of Rparity dark matter can be the lightest neutralino, as in the MSSM, and the LHC model phenomenology is characterized by the fact that only third generation squarks and sleptons are present.Physical review D: Particles and fields 11/2011;  [Show abstract] [Hide abstract]
ABSTRACT: We study an extension of the standard anomaly/gauge mediation scenario where the messenger fields have direct interactions with an extra gauge singlet. This realizes a phenomenologically viable NMSSMlike scenario free of the mub_mu problem. Current cosmological constraints imply a small size for the anomalymediation contributions, unless some source of Rparity violation is permitted. In the latter case the allowed regions in the parameter space can be substantially larger than in the corresponding gaugemediation scenario.Physics Letters B 08/2011; · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We embed the Nextto Minimal Supersymmetric Standard Model into gauge mediation of supersymmetry breaking and study the phenomenology of scenarios where the gaugemediation contributions to soft parameters are deflected by superpotential interactions of the gauge singlet with the messenger fields and the Higgs doublets. This kind of models provide a satisfactory solution to the mub_mu problem of gauge mediation, compatible with the adequate pattern of electroweak symmetry breaking and a realistic spectrum with supersymmetric partners at the TeV scale without requiring a significant fine tuning.Physical review D: Particles and fields 03/2011; 83.  [Show abstract] [Hide abstract]
ABSTRACT: In addition to the narrow spinone resonances ρT, ωT and aT occurring in lowscale technicolor, there will be relatively narrow scalars in the mass range 200 to 600–700 GeV. We study the lightest isoscalar state, σT. In several important respects it is like a heavy Higgs boson with a small vev. It may be discoverable with high luminosity at the LHC where it is produced via weak boson fusion and likely has substantial W+W− and Z0Z0 decay modes.Physics Letters B 11/2010; · 4.57 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present a generalization of the nexttominimal supersymmetric standard model, with an explicit μ term and a supersymmetric mass for the singlet superfield, as a route to alleviating the little hierarchy problem of the minimal supersymmetric standard model (MSSM). Though this model does not address the μ problem of the MSSM, we are able to generate masses for the lightest neutral Higgs boson up to 140 GeV with top squarks below the TeV scale, all couplings perturbative to the gauge unification scale, and with no need to finetune parameters in the scalar potential. This model more closely resembles the MSSM phenomenologically than the canonical nexttominimal supersymmetric standard model.Physical Review Letters 08/2010; 105(9):091802. · 7.73 Impact Factor 
Article: Gaugemediated embedding of the singlet extension of the minimal supersymmetric standard model
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ABSTRACT: We embed the SMSSM—a singlet extension of the minimal supersymmetric standard model with an explicit μterm and supersymmetric mass term—in a gaugemediated supersymmetry breaking scheme. We find that by absolving the singlet of its responsibility for solving the μproblem, we are instead able to solve the little hierarchy problem. Specifically, we find that even with a minimal embedding of the SMSSM into a gaugemediated scheme, we can easily raise the lightest Higgs mass above 114 GeV, while keeping top squarks below the TeV scale, maintaining perturbative unification of the gauge couplings, and without tuning the other parameters of the model.Physical review D: Particles and fields 08/2010; 82(3).  [Show abstract] [Hide abstract]
ABSTRACT: We embed the SMSSM  a singlet extension of the minimal supersymmetric standard model with an explicit muterm and supersymmetric mass term  in a gaugemediated supersymmetry breaking scheme. We find that by absolving the singlet of its responsibility for solving the muproblem, we are instead able to solve the little hierarchy problem naturally. Specifically, we find that even with a minimal embedding of the SMSSM into a gaugemediated scheme, we can easily raise the lightest Higgs mass above 114 GeV, while keeping top squarks below the TeV scale, maintaining perturbative unification of the gauge couplings, and without tuning the other parameters of the model. Comment: 22 pages, 4 PDF figures05/2010;  [Show abstract] [Hide abstract]
ABSTRACT: We present a generalization of the NexttoMinimal Supersymmetric Standard Model (NMSSM), with an explicit muterm and a supersymmetric mass for the singlet superfield, as a route to alleviating the little hierarchy problem of the Minimal Supersymmetric Standard Model (MSSM). Though this model does not address the muproblem of the MSSM, we are able to generate masses for the lightest neutral Higgs boson up to 140 GeV with top squarks below the TeV scale, all couplings perturbative to the gauge unification scale, and with no need to fine tune parameters in the scalar potential. This model, which we call the SMSSM, more closely resembles the MSSM phenomenologically than the NMSSM as usually defined. Comment: 8 pages, 2 figures05/2010;  [Show abstract] [Hide abstract]
ABSTRACT: We develop a 5d model for ElectroWeak physics based on a non compact warped extra dimension of finite length, known as the soft wall scenario, where all the dynamical degrees of freedom propagate in the 5d bulk. We solve the equations of motion and find the allowed spectra, showing that the mass of the lightest fermionic mode behaves as a power law of the effective 4d Yukawa coupling constant, with the exponent being the corresponding fermionic 5d bulk mass. Precisely this non universal behavior allows us to reproduce the hierarchy between the Standard Model (SM) fermion masses (from neutrinos to the top quark) with nonhierarchical fermionic bulk masses. Comment: 26 pages, 4 figures, minor changes, one figured added, version to be publish in PRDPhysical review D: Particles and fields 05/2009;
Publication Stats
2k  Citations  
171.67  Total Impact Points  
Top Journals
Institutions

2008–2013

University of Notre Dame
 Department of Physics
South Bend, Indiana, United States


2012

Universidad Autónoma de Madrid
Madrid, Madrid, Spain


2006–2007

CERN
 Physics Department (PH)
Genève, Geneva, Switzerland


2005

Johns Hopkins University
 Department of Physics and Astronomy
Baltimore, MD, United States


2001

Argonne National Laboratory
Lemont, Illinois, United States


1999–2001

Instituto de Estructura de la Materia
Madrid, Madrid, Spain
