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Register a new userGlobal fits of GUT-scale SUSY models with GAMBIT
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We present the most comprehensive global fits to date of three supersymmetric models motivated by grand unification: the Constrained Minimal Supersymmetric Standard Model (CMSSM), and its Non-Universal Higgs Mass generalisations NUHM1 and NUHM2. We include likelihoods from a number of direct and indirect dark matter searches, a large collection of electroweak precision and flavour observables, direct searches for supersymmetry at LEP and Runs I and II of the LHC, and constraints from Higgs observables. Our analysis improves on existing results not only in terms of the number of included observables, but also in the level of detail with which we treat them, our sampling techniques for scanning the parameter space, and our treatment of nuisance parameters. We show that stau co-annihilation is now ruled out in the CMSSM at more than 95% confidence. Stop co-annihilation turns out to be one of the most promising mechanisms for achieving an appropriate relic density of dark matter in all three models, whilst avoiding all other constraints. We find high-likelihood regions of parameter space featuring light stops and charginos, making them potentially detectable in the near future at the LHC. We also show that tonne-scale direct detection will play a largely complementary role, probing large parts of the remaining viable parameter space, including essentially all models with multi-TeV neutralinos.
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We present comprehensive global fits of supersymmetric (SUSY) models from the Global and Modular Beyond-the-Standard-Model Inference Tool (GAMBIT) collaboration, based on arXiv:1705.07935 and arXiv:1705.07917. We investigate several variants of the minimal supersymmetric standard model, a fully constrained version (CMSSM) with universal scalar ($m_0$), gaugino ($m_{1/2}$) and trilinear masses ($A_0$) at the gauge coupling unification scale, a similar model that is relaxed by adding an extra parameter for the soft Higgs masses (NUHM1), another where the soft Higgs masses are also split (NUHM2) and finally a weak scale MSSM7 model. We use the public GAMBIT global fitting framework and take into account all relevant data to reveal the regions of parameter space with the highest likelihood. Our results reveal that all models have very heavy scenarios that are well out of reach of the LHC, but will be probed by forthcoming dark matter experiments, as well as a stop-co-annihilation region which has better prospects for detection in collider experiments. The stau co-annihilation region is excluded from the CMSSM at $2 sigma$ but is present in the NUHM1 and NUHM2 variants. Finally by relaxing constraints in the NUHM1, NUHM2 and MSSM7 we see additional regions appear: lighter chargino co-annihilation region, sbottom co-annihilation and $h/Z$ funnels.
We present global analyses of effective Higgs portal dark matter models in the frequentist and Bayesian statistical frameworks. Complementing earlier studies of the scalar Higgs portal, we use GAMBIT to determine the preferred mass and coupling ranges for models with vector, Majorana and Dirac fermion dark matter. We also assess the relative plausibility of all four models using Bayesian model comparison. Our analysis includes up-to-date likelihood functions for the dark matter relic density, invisible Higgs decays, and direct and indirect searches for weakly-interacting dark matter including the latest XENON1T data. We also account for important uncertainties arising from the local density and velocity distribution of dark matter, nuclear matrix elements relevant to direct detection, and Standard Model masses and couplings. In all Higgs portal models, we find parameter regions that can explain all of dark matter and give a good fit to all data. The case of vector dark matter requires the most tuning and is therefore slightly disfavoured from a Bayesian point of view. In the case of fermionic dark matter, we find a strong preference for including a CP-violating phase that allows suppression of constraints from direct detection experiments, with odds in favour of CP violation of the order of 100:1. Finally, we present DDCalc 2.0.0, a tool for calculating direct detection observables and likelihoods for arbitrary non-relativistic effective operators.
Supersymmetric $SO(10)$ grand unified models with renormalizable Yukawa couplings involving only ${bf 10}$ and $overline{bf 126}$ Higgs fields have been shown to realize the fermion masses and mixings economically. In previous works, the sum rule of the fermion mass matrices are given by inputting the quark matrices, and the neutrino mixings are predicted in this framework. Now the three neutrino mixings have been measured, and in this paper, we give the sum rule by inputting the lepton mass matrices, which makes clear certain features of the solution, especially if the vacuum expectation values of ${bf 126}+ overline{bf126}$ ($v_R$) are large and the right-handed neutrinos are heavy. We perform the $chi^2$ analyses to fit the fermion masses and mixings using the sum rule. In previous works, the best fit appears at $v_R sim 10^{13}$ GeV, and the fit at the large $v_R$ scale ($sim 10^{16}$ GeV) has been less investigated. Our expression of the sum rule has a benefit to understand the flavor structure in the large $v_R$ solution. Using the fit results, we perform the calculation of the $mu to egamma$ process and the electric dipole moment of electron, and the importance of $v_R$ dependence emerges in low energy phenomena. We also show the prediction of the CP phase in the neutrino oscillations, which can be tested in the near future.
SO(10) GUT models with only small Higgs fields use higher-dimensional operators to generate realistic fermion mass matrices. In particular, a Higgs field in the spinor representation, 16^d_H, acquires a weak scale vev. We include the weak vev of the corresponding field bar{16}^u_H and investigate the effect on two successful models, one by Albright and Barr (AB) and another by Babu, Pati and Wilczek (BPW). We find that the BPW model is a particular case within a class of models with identical fermion masses and mixings. In contrast, we expect corrections to the parameters of AB-type models.
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