Daniel E. López-Fogliani

University of Buenos Aires, Buenos Aires, Buenos Aires F.D., Argentina

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Publications (16)42.49 Total impact

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    ABSTRACT: The extended field content of the "$\mu$ from $\nu$" supersymmetric standard model ($\mu\nu$SSM) can accommodate very light scalars, pseudoscalars and neutralinos in certain regions of the parameter space with leading right-handed sneutrino and neutrino composition, respectively. Direct production of these states at colliders is suppressed due to gauge singlet nature. Nevertheless, production of these states is possible in the decay cascades of heavier ones. In this letter we emphasis how these light states can lead to unusual signals from $Z$ or $W^\pm$ boson decays at the LHC with prompt or displaced multi-leptons/jets at the final states. These new modes would give distinct evidence of new physics even when direct searches remain unsuccessful. We address possibilities to probe these non-standard signatures with ongoing or upcoming collider experiment.
    03/2014;
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    ABSTRACT: The "$\mu$ from $\nu$" supersymmetric standard model ($\mu\nu$SSM) cures the $\mu$-problem and concurrently reproduces measured neutrino data by using a set of usual right-handed neutrino superfields. Recently, the LHC has revealed the first scalar boson which naturally makes it tempting to test $\mu\nu$SSM in the light of this new discovery. We show that this new scalar while decaying to a pair of unstable long-lived neutralinos, can lead to a distinct signal with non-prompt multileptons. With concomitant collider analysis we show that this signal provides an unmistakable signature of the model, pronounced with light neutralinos. Evidence of this signal is well envisaged with sophisticated displaced vertex analysis, which deserves experimental attention.
    Physical review D: Particles and fields 11/2012; 88(1).
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    Javier Fidalgo, Daniel E. Lopez-Fogliani, Carlos Munoz, Roberto Ruiz de Austri
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    ABSTRACT: The $\mu\nu$SSM is a supersymmetric standard model that accounts for light neutrino masses and solves the $\mu$ problem of the MSSM by simply using right-handed neutrino superfields. Since this mechanism breaks R-parity, a peculiar structure for the mass matrices is generated. The neutral Higgses are mixed with the right- and left-handed sneutrinos producing 8$\times$8 neutral scalar mass matrices. We analyse the Higgs sector of the $\mu\nu$SSM in detail, with special emphasis in possible signals at colliders. After studying in general the decays of the Higges, we focus on those processes that are genuine of the $\mu\nu$SSM, and could serve to distinguish it from other supersymmetric models. In particular, we present viable benchmark points for LHC searches. For example, we find decays of a MSSM-like Higgs into two lightest neutralinos, with the latter decaying inside the detector leading to displaced vertices, and producing final states with 4 and 8 $b$-jets plus missing energy. Final states with leptons and missing energy are also found.
    Journal of High Energy Physics - J HIGH ENERGY PHYS. 07/2011; 10.
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    ABSTRACT: Motivated by the recent re-confirmation by CoGENT of the low-energy excess of events observed last year, and the recent improved limits from the XENON-100 experiment that are in contention with the CoGENT data, we re-examine the low mass neutralino region of the Minimal Supersymmetric Standard Model and of the Next-to-Minimal Supersymmetric Standard Model, both without assuming gaugino mass unification. We make several focused scans for each model, determining conservative constraints on input parameters. We then determine how these constraints are made increasingly stringent as we re-invoke our experimental constraints involving the dark matter relic abundance, collider constraints from LEP and the Tevatron, and then from flavour physics, as a series of successive 2 sigma hard cuts. We find that for both models, when all relevant constraints are applied in this fashion, we do not generate neutralino LSPs that possess a spin-independent scattering cross section in excess of 10^-5 pb and a mass ~7 GeV < m_chi < ~9 GeV that is necessary in order to explain the CoGENT observations.
    07/2011;
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    ABSTRACT: We examine the extent to which it is possible to realize the NMSSM "ideal Higgs" models espoused in several papers by Gunion et al in the context of partially universal GUT scale boundary conditions. To this end we use the powerful methodology of nested sampling. We pay particular attention to whether ideal-Higgs-like points not only pass LEP constraints but are also acceptable in terms of the numerous constraints now available, including those from the Tevatron and $B$-factory data, $(g-2)_\mu$ and the relic density $\Omega h^2$. In general for this particular methodology and range of parameters chosen, very few points corresponding to said previous studies were found, and those that were found were at best $2\sigma$ away from the preferred relic density value. Instead, there exist a class of points, which combine a mostly singlet-like Higgs with a mostly singlino-like neutralino coannihilating with the lightest stau, that are able to effectively pass all implemented constraints in the region $80<m_h<100$. It seems that the spin-independent direct detection cross section acts as a key discriminator between ideal Higgs points and the hard to detect singlino-like points.
    Physical review D: Particles and fields 05/2011; 84.
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    Daniel E. Lopez-Fogliani
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    ABSTRACT: The $\mu \nu$SSM proposes to use right-handed neutrino supermultiplets in order to generate the $\mu$ term and neutrino masses simultaneously. We discuss neutrino physics and the associated electroweak seesaw mechanism in this model. We show how to obtain, from the neutralino-neutrino mass matrix of the $\mu \nu$SSM, the effective neutrino mass matrix. In particular we discuss certain limits of this matrix that clarify the neutrino-sector behavior of the model. We also show that current data on neutrino masses and mixing angles can easily be reproduced. These constraints can be fulfilled even with a diagonal neutrino Yukawa matrix, since this seesaw does not involve only the right-handed neutrinos but also the MSSM neutralinos. To obtain the correct neutrino angles turns out to be easy due to the following characteristics of this seesaw: R-parity is broken and the relevant scale is the electroweak one. Comment: 7 pages, 1 figure. Talk given at "BUE, CTP International Conference on Neutrino Physics in the LHC Era", Luxor, Egypt, 15-19 Nov. 2009.
    04/2010;
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    Ki-Young Choi, Daniel E. López-Fogliani, Carlos Muñoz, Roberto Ruiz de Austri
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    ABSTRACT: The munuSSM provides a solution to the mu-problem of the MSSM and explains the origin of neutrino masses by simply using right-handed neutrino superfields. Given that R-parity is broken in this model, the gravitino is a natural candidate for dark matter since its lifetime becomes much longer than the age of the Universe. We consider the implications of gravitino dark matter in the munuSSM, analyzing in particular the prospects for detecting gamma rays from decaying gravitinos. If the gravitino explains the whole dark matter component, a gravitino mass larger than 20GeV is disfavored by the isotropic diffuse photon background measurements. On the other hand, a gravitino with a mass range between 0.1-20 GeV gives rise to a signal that might be observed by the FERMI satellite. In this way important regions of the parameter space of the munuSSM can be checked.
    Journal of Cosmology and Astroparticle Physics 01/2010; 3(03):028-028. · 6.04 Impact Factor
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    ABSTRACT: We perform a first global exploration of the constrained next-to-minimal supersymmetric standard model using Bayesian statistics. We derive several global features of the model and find that, in some contrast to initial expectations, they closely resemble those of the constrained minimal supersymmetric standard model. This remains true even away from the decoupling limit which is nevertheless strongly preferred. We present ensuing implications for several key observables, including collider signatures and predictions for direct detection of dark matter.
    Physical review D: Particles and fields 11/2009; 80(9).
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    ABSTRACT: The μνSSM provides a solution to the μ problem of the MSSM and explains the origin of neutrino masses by simply using right-handed neutrino superfields. We have completed the analysis of the vacua in this model, studying the possibility of spontaneous CP violation through complex Higgs and sneutrino vacuum expectation values. As a consequence of this process, a complex MNS matrix can be present. Besides, we have discussed the neutrino physics and the associated electroweak seesaw mechanism in the μνSSM, including also phases. Current data on neutrino masses and mixing angles can easily be reproduced.
    Journal of High Energy Physics 08/2009; 2009(08):105. · 5.62 Impact Factor
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    ABSTRACT: We perform a first global exploration of the Constrained Next-to-Minimal Supersymmetric Standard Model using Bayesian statistics. We derive several global features of the model and find that, in some contrast to initial expectations, they closely resemble the Constrained MSSM. This remains true even away from the decoupling limit which is nevertheless strongly preferred. We present ensuing implications for several key observables, including collider signatures and predictions for direct detection of dark matter.
    06/2009;
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    ABSTRACT: The μνSSM is a supersymmetric standard model that solves the μ problem of the MSSM using the R-parity breaking couplings between the right-handed neutrino superfields and the Higgses in the superpotential, λi cidu. The μ term is generated spontaneously through sneutrino vacuum expectation values, μ = λici, once the electroweak symmetry is broken. In addition, the couplings κijkcicjck forbid a global U(1) symmetry avoiding the existence of a Goldstone boson, and also contribute to spontaneously generate Majorana masses for neutrinos at the electroweak scale. Following this proposal, we have analysed in detail the parameter space of the μνSSM. In particular, we have studied viable regions avoiding false minima and tachyons, as well as fulfilling the Landau pole constraint. We have also computed the associated spectrum, paying special attention to the mass of the lightest Higgs. The presence of right and left-handed sneutrino vacuum expectation values leads to a peculiar structure for the mass matrices. The most important consequence is that neutralinos are mixed with neutrinos, and neutral Higgses with sneutrinos.
    Journal of High Energy Physics 12/2008; 2008(12):099. · 5.62 Impact Factor
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    D G Cerdeño, E Gabrielli, D E López-Fogliani, C Muñoz, A M Teixeira
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    ABSTRACT: The viability of the lightest neutralino as a dark matter candidate in the next-to-minimal supersymmetric standard model is analysed. We carry out a thorough analysis of the parameter space, taking into account accelerator constraints as well as bounds on low-energy observables, such as the muon anomalous magnetic moment and rare K and B meson decays. The neutralino relic density is also evaluated and consistency with present bounds imposed. Finally, the neutralino direct detection cross section is calculated in the allowed regions of the parameter space and compared to the sensitivities of present and projected dark matter experiments. Regions of the parameter space are found where experimental constraints are fulfilled, the lightest neutralino has the correct relic abundance and its detection cross section is within the reach of dark matter detectors. This is possible in the presence of very light singlet-like Higgses and when the neutralino is either light enough so that some annihilation channels are kinematically forbidden, or has a large singlino component.
    Journal of Cosmology and Astroparticle Physics 03/2007; 2007(06). · 6.04 Impact Factor
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    D E López-Fogliani, C Muñoz
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    ABSTRACT: The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type H2Lnuc. We propose to use these superfields to solve the mu problem of the MSSM without having to introduce an extra singlet superfield as in the case of the next-to-MSSM (NMSSM). In particular, terms of the type nuc H1H2 in the superpotential may carry out this task spontaneously through neutrino vacuum expectation values. In addition, terms of the type (nuc)3 avoid the presence of axions and generate effective Majorana masses for neutrinos at the electroweak scale. On the other hand, these terms break lepton number and R parity explicitly. For Dirac masses of the neutrinos of order 10(-4) GeV, eigenvalues reproducing the correct scale of neutrino masses are obtained.
    Physical Review Letters 08/2006; 97(4):041801. · 7.94 Impact Factor
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    D. G. Cerdeno, C. Hugonie, D. E. Lopez-Fogliani, C. Munoz, A. M. Teixeira
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    ABSTRACT: We analyse the direct detection of neutralino dark matter in the framework of the Next-to-Minimal Supersymmetric Standard Model. After performing a detailed analysis of the parameter space, taking into account all the available constraints from LEPII, we compute the neutralino-nucleon cross section, and compare the results with the sensitivity of detectors. We find that sizable values for the detection cross section, within the reach of dark matter detectors, are attainable in this framework. For example, neutralino-proton cross sections compatible with the sensitivity of present experiments can be obtained due to the exchange of very light Higgses with $m_{h_1^0}\lsim 70$ GeV. Such Higgses have a significant singlet composition, thus escaping detection and being in agreement with accelerator data. The lightest neutralino in these cases exhibits a large singlino-Higgsino composition, and a mass in the range $50\lsim m_{\tilde\chi_1^0}\lsim 100$ GeV.
    Journal of High Energy Physics 09/2004; · 5.62 Impact Factor
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    Javier Fidalgo, Daniel E. López-Fogliani, Carlos Muñoz, Roberto Ruiz de Austri
    [show abstract] [hide abstract]
    ABSTRACT: The μνSSM is a supersymmetric standard model that accounts for light neutrino masses and solves the μ problem of the MSSM by simply using right-handed neutrino superfields. Since this mechanism breaks R-parity, a peculiar structure for the mass matrices is generated. The neutral Higgses are mixed with the right- and left-handed sneutrinos producing 8 × 8 neutral scalar mass matrices. We analyse the Higgs sector of the μνSSM in detail, with special emphasis in possible signals at colliders. After studying in general the decays of the Higges, we focus on those processes that are genuine of the μνSSM, and could serve to distinguish it form other supersymmetric models. In particular, we present viable benchmark points for LHC searches. For example, we find decays of a MSSM-like Higgs into two lightest neutralinos, with the latter decaying inside the detector leading to displaced vertices, and producing final states with 4 and 8 b-jets plus missing energy. Final states with leptons and missing energy are also found.
    Journal of High Energy Physics 2011(10). · 5.62 Impact Factor
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    Nicolas Escudero, Daniel E. Lopez-Fogliani, Carlos Munoz
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    ABSTRACT: The �ν SSM is a supersymmetric standard model that solves theproblem of the MSSM using the R-parity breaking couplings between the right-handed neutrino superfields and the Higgses in the superpotential, λi ˆ νc i ˆ Hd ˆ Hu. Theterm is generated spontaneously through sneutrino

Publication Stats

165 Citations
42.49 Total Impact Points

Institutions

  • 2012
    • University of Buenos Aires
      • Department of Physics (FI)
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2011
    • Université Paris-Sud 11
      • Laboratoire de Physique Théorique d'Orsay
      Orsay, Île-de-France, France
  • 2004–2010
    • Universidad Autónoma de Madrid
      • Department of Theoretical physics
      Madrid, Madrid, Spain
  • 2008–2009
    • The University of Sheffield
      • Department of Physics and Astronomy
      Sheffield, ENG, United Kingdom