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SuSpect3: A C++ Code for the Supersymmetric and Higgs Particle Spectrum of the MSSM
Auteur(s): Kneur J.L., Moultaka G., Ughetto M., Zerwas Dirk, Djouadi Abdelhak
(Document sans référence bibliographique) Texte intégral en Openaccess :
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Ref Arxiv: 2211.16956
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Résumé: We present the program SuSpect3 that calculates the masses and couplings of the Higgs and supersymmetric particles predicted by the Minimal Supersymmetric Standard Model (MSSM). The model is implemented in both its nonconstrained version, the MSSM, and its constrained versions, such as the minimal supergravity and the gauge or anomaly mediated supersymmetry breaking models, in which the soft supersymmetrybreaking parameters obey certain universal boundary conditions at the high energy scale. The low energy parameters are then obtained using renormalization group equations and electroweak symmetry breaking, and all the dominant radiative corrections have been consistently implemented. SuSpect3 is a major rewrite, in C++ object oriented programming, of the FORTRAN code SuSpect. It includes all the features of the earlier code in an improved and updated manner, and involves new options such as compressed SUSY scenarios, an MSSMinflation model and the possibility of using the observed Higgs mass as an input. The main features and the use of the program are explained.
Commentaires: 33 pages



The hMSSM with a Light Gaugino/Higgsino Sector:Implications for Collider and Astroparticle Physics
Auteur(s): Arcadi Giorgio, Djouadi Abdelhak, He HongJian, Kneur J.L., Xiao RuiQing
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Ref Arxiv: 2206.11881
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Résumé: The hMSSM is a special parameterization of the minimal supersymmetric extension of the Standard Model (MSSM) in which the mass of the lightest Higgs boson is automatically set to the LHC measured value, $M_h\!\!=\!\! 125$ GeV, by adjusting the supersymmetric particle spectrum such that it provides the required amount of radiative corrections to the Higgs boson masses. The latter spectrum was in general assumed to be very heavy, as indicated by the present exclusion limits of the LHC, not to affect the phenomenology of the Higgs sector. In this work, we investigate the impact on the hMSSM by a light gaugino and higgsino sector, that is allowed by the present LHC data. In particular, we discuss the radiative corrections due to charginos and neutralinos to the Higgs boson masses and couplings and show that an hMSSM can still be realized in this context. We first describe how this scenario is implemented in the package SuSpect that generates the MSSM Higgs and supersymmetric spectra. We then analyze the possible impact of Higgs boson decays into these new states, as well as the reverse cascade channels with Higgs bosons in the final states, for the constraints on the MSSM Higgs sector at the LHC. We further explore the cosmological constraints on the hMSSM with a light gauginohiggsino spectrum. We analyze the relic abundance of the lightest neutralino as a candidate of the dark matter in the Universe and the constraints on its mass and couplings by the present and future astroparticle physics experiments.



Holographic models of composite Higgs in the Veneziano limit. Part II. Fermionic sector
Auteur(s): Elander D., Frigerio M., Knecht Marc, Kneur J.L.
(Article) Publié:
Jhep, vol. 05 p.066 (2022)
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Ref Arxiv: 2112.14740
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DOI: 10.1007/JHEP05(2022)066
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Résumé: We continue our study of stronglycoupled, approximately scaleinvariant gauge theories with a large number of flavours, which provide a suitable ultraviolet completion of the compositeHiggs scenario. We identify the requisite operators to realise partial compositeness of the StandardModel fermions. In order to compute the spectrum of composite fermionic states, we extend the bottomup holographic models, which we previously introduced to capture the main features of the nonperturbative dynamics in the Veneziano limit, by adding fermion fields in the bulk. We identify regions in parameter space where some fermionic bound states become light, depending in particular on the number of flavours, the operator scaling dimensions, and the bulk Yukawa couplings. We also observe a dense spectrum of states, when multiscale dynamics is induced by a large backreaction of bulk scalars on the geometry. Adapting the formalism of the holographic Wilsonian renormalisation group, we study the linear coupling between the composite and elementary fermions, as a function of energy scale. We find that, in some circumstances, the associated operators are dangerously irrelevant: the renormalisationgroup flow gives rise to a large linear coupling in the infrared, even when it is irrelevant from the point of view of the ultraviolet fixed point. We finally compute the partially composite spectrum, correlate it with the analysis of the flow, and assess the potential phenomenological implications, e.g. for the topquark partners.



The Higgs boson mass as fundamental parameter of the minimal supersymmetric standard model
Auteur(s): ElKosseifi Rima, Kneur J.L., Moultaka G., Zerwas Dirk
(Article) Publié:
European Physical Journal C Particles And Fields, vol. 82 p.657 (2022)
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Ref HAL: hal03574108_v1
Ref Arxiv: 2202.06919
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DOI: 10.1140/epjc/s10052022106064
WoS: WOS:000834632900001
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Résumé: In the Minimal Supersymmetric Standard Model (MSSM) the mass of the lightest neutral Higgs boson is determined by the supersymmetric parameters. In the $m_h$MSSM the precisely measured Higgs boson replaces the trilinear coupling $A_t$ as input parameter. Expressions are derived to extract $A_t$ in a semianalytical form as a function of the light Higgs boson (pole) mass. An algorithm is developed and implemented at twoloop precision, generalizable to higher orders, to perform this inversion consistently. The result of the algorithm, implemented in the SuSpect spectrum calculator, is illustrated on a parameter set compatible with LHC measurements.



All order resummed leading and nexttoleading soft modes of dense QCD pressure
Auteur(s): Fernandez L., Kneur J.L.
(Article) Publié:
Phys.rev.lett., vol. 129 p.212001 (2022)
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Ref Arxiv: 2109.02410
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Résumé: The cold and dense QCD equation of state (EoS) at high baryon chemical potential $\mu_B$ involves at order $\alpha^2_S$ an allloop summation of the soft mode $m_E\sim \alpha_S^{1/2} \mu_B$ contributions. Recently, the complete soft contributions at order $\alpha^3_S$ were calculated, using the hard thermal loop (HTL) formalism. By identifying {\em massive} renormalization group (RG) properties within HTL, we resum to all orders $\alpha_S^p, p\ge 3$ the leading and nexttoleading logarithmic soft contributions. We obtain compact analytical expressions, that show visible deviations from the stateofthe art results, and noticeably reduced residual scale dependence. Our results should help to reduce uncertainties in extending the EoS in the intermediate $\mu_B$ regime, relevant in particular for the phenomenology of neutron stars.



Renormalization group optimized $\lambda \phi^4$ pressure at nexttonexttoleading order
Auteur(s): Fernandez L., Kneur J.L.
(Article) Publié:
Physical Review D, vol. 104 p.096012 (2021)
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Ref Arxiv: 2107.13328
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DOI: 10.1103/PhysRevD.104.096012
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Résumé: We investigate the renormalization group optimized perturbation theory (RGOPT) at the nexttonexttoleading order (NNLO) for the thermal scalar field theory. From comparing three thus available successive RGOPT orders, we illustrate the efficient resummation and very good apparent convergence properties of the method. In particular, the remnant renormalization scale dependence of thermodynamical quantities is drastically improved as compared to both standard perturbative expansions and other related resummation methods, such as the screened perturbation theory. Our present results thus constitute a useful first NNLO illustration in view of NNLO applications of this approach to the more involved thermal QCD.



Renormalization group improved pressure for hot and dense quark matter
Auteur(s): Kneur J.L., Pinto Marcus Benghi, Restrepo Tulio E.
(Article) Publié:
Physical Review D, vol. 104 p.034003 (2021)
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Ref HAL: hal03129450_v1
Ref Arxiv: 2101.08240
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DOI: 10.1103/PhysRevD.104.034003
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Résumé: We apply the renormalization group optimized perturbation theory (RGOPT) to evaluate the quark contribution to the QCD pressure at finite temperatures and baryonic densities, at nexttoleading order (NLO). Our results are compared to NLO and stateoftheart higher orders of standard perturbative QCD (pQCD) and hard thermal loop perturbation theory (HTLpt). The RGOPT provides an all order resummed pressure in a welldefined approximation, exhibiting a drastically better remnant renormalization scale dependence than pQCD, thanks to builtin renormalization group invariance consistency. At NLO, upon simply adding to the RGOPTresummed quark contributions the purely perturbative NLO glue contribution, our results show a remarkable agreement with ab initio lattice simulation data for temperatures $0.25\lesssim T\lesssim 1\text{\hspace{0.17em}}\text{\hspace{0.17em}}\mathrm{GeV}$, with a remnant scale dependence drastically reduced as compared to HTLpt.
