Publications (10)3.63 Total impact
-
Article: Asymmetry at LHC for an U(1)' anomalous extension of MSSM
[show abstract] [hide abstract]
ABSTRACT: The measurement of the forward-backward asymmetry at LHC could be an important instrument to pinpoint the features of extra neutral gauge particles obtained by an extension of the gauge symmetry group of the standard model. For definitiveness, in this work we consider an extension of the gauge group of the Minimal Supersymmetric Standard Model by an extra anomalous U(1) gauge symmetry (MiAUMSSM). We focus on pp -> e+e- at LHC and use four different definitions of the asymmetry obtained implementing four different cuts on the directions and momenta of the final states of our process of interest. The calculations are performed without imposing constraints on the charges of the extra Z's of our model, since the anomaly is cancelled by a Green-Schwarz type mechanism. Our final result is a fit of our data with a polynomial in the charges from which to extract the values of the charges given the experimental result.07/2012; -
Article: Stückelino dark matter in anomalous U(1)′ models
[show abstract] [hide abstract]
ABSTRACT: We study a possible dark matter candidate in the framework of a minimal anomalous U(1)′ extension of the MSSM. It turns out that in a suitable decoupling limit the Stückelino, the fermionic degree of freedom of the Stückelberg multiplet, is the lightest supersymmetric particle (LSP). We compute the relic density of this particle including coannihilations with the next to lightest supersymmetric particle (NLSP) and with the next to next to lightest supersymmetric particle (NNLSP), which are assumed to be almost degenerate in mass. This assumption is needed in order to satisfy the stringent limits that the Wilkinson Microwave Anisotropy Probe (WMAP) puts on the relic density. We find that the WMAP constraints can be satisfied by different NLSP and NNLSP configurations as a function of the mass gap with the LSP. These results hold in the parameter space region where the model remains perturbative.European Physical Journal C 04/2012; 69(3):455-465. · 3.63 Impact Factor -
Article: Dark Matter in Anomalous $U(1)'$ Models with neutral mixing
[show abstract] [hide abstract]
ABSTRACT: We study the lightest masses in the fermionic sector of an anomalous $U(1)'$ extension of the minimal supersymmetric standard model inspired by brane constructions. The LSP of this model is an XWIMP (extremely weak interaction particle) which is shown to have a relic density satisfying WMAP data. This computation is carried out numerically after having adapted the DarkSUSY package to our case.05/2011; -
Article: St\"uckelino Dark Matter in Anomalous U(1)' Models
[show abstract] [hide abstract]
ABSTRACT: We study a possible dark matter candidate in the framework of a minimal anomalous $U(1)'$ extension of the MSSM. It turns out that in a suitable decoupling limit the St\"uckelino, the fermionic degree of freedom of the St\"uckelberg multiplet, is the lightest supersymmetric particle (LSP). We compute the relic density of this particle including coannihilations with the next to lightest supersymmetric particle (NLSP) and with the next to next to lightest supersymmetric particle (NNLSP) which are assumed almost degenerate in mass. This assumption is needed in order to satisfy the stringent limits that the Wilkinson Microwave Anisotropy Probe (WMAP) puts on the relic density. We find that the WMAP constraints can be satisifed by different NLSP and NNLSP configurations as a function of the mass gap with the LSP. These results hold in the parameter space region where the model remains perturbative.11/2008; -
Article: Minimal Anomalous U(1)' Extension of the MSSM
[show abstract] [hide abstract]
ABSTRACT: We study an extension of the MSSM by an anomalous abelian vector multiplet and a St\"uckelberg multiplet. The anomalies are cancelled by the Green-Schwarz mechanism and the addition of Chern-Simons terms. The advantage of this choice over the standard one is that it allows for arbitrary values of the quantum numbers of the extra $U(1)$. As a first step towards the study of hadron annihilations producing four leptons in the final state (a clean signal which might be studied at LHC) we then compute the decays $Z'\to Z_0 \g$ and $Z'\to Z_0 Z_0$. We find that the largest values of the decay rate is $\sim 10^{-4}$ GeV, while the expected number of events per year at LHC is at most of the order of 10.05/2008; -
Article: Deflected Anomaly Mediation and Neutralino Dark Matter
[show abstract] [hide abstract]
ABSTRACT: We study the phenomenology of the neutralino dark matter in the so called deflected anomaly mediation scenario. This scheme is obtained from the minimal anomaly mediated scenario by introducing a gauge mediated sector with $N_f$ messenger fields. Unlike the former scheme the latter has no tachyons. We find that the neutralino is still the LSP in a wide region of the parameter space: it is essentially a pure bino in the scenario with $N_f=1$ while it can also be a pure higgsino for $N_f>1$. This is very different from the naive anomaly mediated scenario which predicts a wino like neutralino. Moreover we do not find any tachyonic scalars in this scheme. After computing the relic density (considering all the possible coannihilations) we find that there are regions in the parameter space with values compatible with the latest WMAP results with no need to consider moduli fields that decay in the early universe.12/2006; -
Article: Extra-Dimensions and Dark Matter
[show abstract] [hide abstract]
ABSTRACT: In this paper we study the general scenario of an effective theory coming from the compactification of a higher dimensional theory in a string inspired setting. This leads to gauge coupling unification at an intermediate mass scale. After having computed all the threshold corrections (due to Kaluza-Klein modes) to the running of the couplings of the MSSM we embark in a detailed phenomenological analysis of the model, based on the numerical package DarkSUSY, to find constraints on the scenario from Dark Matter data. The mass spectrum of the theory does not have tachyons. Moreover we find that the neutralino is still the LSP with a relic density compatible with the most recent experimental data. With respect to the standard mSUGRA scenario we find that the neutralino is higgsino like in most of the parameter space. Our modifications to the DarkSUSY package will be shortly available upon request. Comment: 37 pages, 17 figures, uses feynmf.sty, two references added03/2006; -
Article: Search for supersymmetric dark matter with GLAST
[show abstract] [hide abstract]
ABSTRACT: The detection of exotic cosmic rays due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. The study of the spectrum of gamma-rays, antiprotons and positrons offers goof possibilities to perform this search in a significant portion of the Minimal Supersymmetric Standard Model parameter space. In particular the EGRET team have seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation with standard processes. We will review the limits achievable with the experiment GLAST taking into account the LEP results and we will compare this method with the antiproton and positrons experiments, and direct detection underground experiments.Nuclear Physics B - Proceedings Supplements. -
Article: The Galactic center as a dark matter gamma-ray source
[show abstract] [hide abstract]
ABSTRACT: The EGRET telescope has identified a gamma-ray source at the Galactic center. We point out here that the spectral features of this source are compatible with the gamma-ray flux induced by pair annihilations of dark matter weakly interacting massive particles (WIMPs). We show that the discrimination between this interpretation and other viable explanations will be possible with GLAST, the next major gamma-ray telescope in space, on the basis of both the spectral and the angular signature of the WIMP-induced component. If, on the other hand, the data will point to an alternative explanation, we prove that there will still be the possibility for GLAST to single out a weaker dark matter source at the Galactic center. The potential of GLAST has been explored both in the context of a generic simplified toy-model for WIMP dark matter, and in a more specific setup, the case of dark matter neutralinos in the minimal supergravity framework. In the latter, we find that even in the case of moderate dark matter densities in the Galactic center region, there are portions of the parameter space which will be probed by GLAST.Astroparticle Physics. -
Article: Search for dark matter with GLAST
[show abstract] [hide abstract]
ABSTRACT: The detection of exotic cosmic rays due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. The study of the spectrum of gamma-rays, antiprotons and positrons offers good possibilities to perform this search in a significant portion of the Minimal Supersymmetric Standard Model parameter space. In particular the EGRET team have seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation with standard processes. We will review the limits achievable with the experiment GLAST taking into accounts the LEP results and we will compare this method with the antiproton and positrons experiments.Nuclear Physics B - Proceedings Supplements.
Top co-authors
Top Journals
Institutions
-
2006–2012
-
Università degli Studi di Roma "Tor Vergata"
- Dipartimento di Fisica
Roma, Latium, Italy
-
