scholarly journals Probing unified theories with reduced couplings at future hadron colliders

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
S. Heinemeyer ◽  
J. Kalinowski ◽  
W. Kotlarski ◽  
M. Mondragón ◽  
G. Patellis ◽  
...  

AbstractThe search for renormalization group invariant relations among parameters to all orders in perturbation theory constitutes the basis of the reduction of couplings concept. Reduction of couplings can be achieved in certain $$N=1$$ N = 1 supersymmetric grand unified theories and few of them can become even finite at all loops. We review the basic idea, the tools that have been developed as well as the resulting theories in which successful reduction of couplings has been achieved so far. These include: (i) a reduced version of the minimal $$N = 1\ SU(5)$$ N = 1 S U ( 5 ) model, (ii) an all-loop finite $$N = 1\ SU(5)$$ N = 1 S U ( 5 ) model, (iii) a two-loop finite $$N = 1\ SU(3)^3$$ N = 1 S U ( 3 ) 3 model and finally (vi) a reduced version of the Minimal Supersymmetric Standard Model. In this paper we present a number of benchmark scenarios for each model and investigate their observability at existing and future hadron colliders. The heavy supersymmetric spectra featured by each of the above models are found to be beyond the reach of the 14 TeV HL-LHC. It is also found that the reduced version of the MSSM is already ruled out by the LHC searches for heavy neutral MSSM Higgs bosons. In turn the discovery potential of the 100 TeV FCC-hh is investigated and found that large parts of the predicted spectrum of these models can be tested, but the higher mass regions are beyond the reach even of the FCC-hh.

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Andreas Crivellin ◽  
Dario Müller ◽  
Francesco Saturnino

Abstract Leptoquarks (LQs) are predicted within Grand Unified Theories and are well motivated by the current flavor anomalies. In this article we investigate the impact of scalar LQs on Higgs decays and oblique corrections as complementary observables in the search for them. Taking into account all five LQ representations under the Standard Model gauge group and including the most general mixing among them, we calculate the effects in h → γγ, h → gg, h → Zγ and the Peskin-Takeuchi parameters S, T and U. We find that these observables depend on the same Lagrangian parameters, leading to interesting correlations among them. While the current experimental bounds only yield weak constraints on the model, these correlations can be used to distinguish different LQ representations at future colliders (ILC, CLIC, FCC-ee and FCC-hh), whose discovery potential we are going to discuss.


2017 ◽  
Vol 32 (33) ◽  
pp. 1745005
Author(s):  
Fei Wang ◽  
Wenyu Wang ◽  
Lei Wu ◽  
Jin Min Yang ◽  
Mengchao Zhang

In this work, we investigate the degenerate heavy Higgs bosons in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) by introducing vector-like particles. Such an extension is well motivated from the top-down view since some grand unified theories usually predict the existence of singlet scalars and vector-like particles at weak scale. Under the constraints from the Large Hadron Collider (LHC) and dark matter experiments, we find that (1) the null results of searching for high mass resonances have tightly constrained the parameter space; (2) two degenerate heavy singlet Higgs bosons [Formula: see text] and [Formula: see text] can sizably decay to [Formula: see text] invisibly. Therefore, search for the monojet events through the process [Formula: see text] may further test our scenario at the future LHC.


2014 ◽  
Vol 29 (18) ◽  
pp. 1430032 ◽  
Author(s):  
S. Heinemeyer ◽  
M. Mondragón ◽  
G. Zoupanos

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power. We confront the predictions of an SU(5) FUT with the top and bottom quark masses and other low-energy experimental constraints, resulting in a relatively heavy SUSY spectrum, naturally consistent with the nonobservation of those particles at the LHC. The light Higgs boson mass is automatically predicted in the range compatible with the Higgs discovery at the LHC. Requiring a light Higgs boson mass in the precise range of Mh= 125.6 ±2.1 GeV favors the lower part of the allowed spectrum, resulting in clear predictions for the discovery potential at current and future pp, as well as future e+e-colliders.


2021 ◽  
Vol 61 ◽  
pp. 1-16
Author(s):  
Daniele Corradetti ◽  

Recent papers contributed revitalizing the study of the exceptional Jordan algebra $\mathfrak{h}_{3}(\mathbb{O})$ in its relations with the true Standard Model gauge group $\mathrm{G}_{SM}$. The absence of complex representations of $\mathrm{F}_{4}$ does not allow $\Aut\left(\mathfrak{h}_{3}(\mathbb{O})\right)$ to be a candidate for any Grand Unified Theories, but the automorphisms of the complexification of this algebra, i.e., $\mathfrak{h}_{3}^{\mathbb{C}}(\mathbb{O})$, are isomorphic to the compact form of $\mathrm{E}_{6}$ and similar constructions lead to the gauge group of the minimal left-right symmetric extension of the Standard Model.


1994 ◽  
Vol 09 (11) ◽  
pp. 1747-1785 ◽  
Author(s):  
ANDRÉ SOPCZAK

Detailed studies of neutral and charged Higgs boson pair production with full statistic detector simulations around [Formula: see text] with 500 pb−1 are presented in the context of a review of the Higgs boson discovery potential at LEP200. Already in the first phase of LEP200, a significant increase of the mass parameter space compared to LEP1 for the discovery of nonminimal Higgs bosons will be possible, while the mass range for the discovery of the minimal Standard Model Higgs boson will increase only marginally. The requirements for a decisive test of the Minimal Supersymmetric extension of the Standard Model (MSSM) at a later stage of LEP200 are discussed. A sensitivity mass range is given for charged Higgs bosons.


Author(s):  
STEPHEN M. BARR ◽  
XAVIER CALMET

We discuss how a model for the electroweak interactions without a Higgs could be embedded into a grand unified theory. The requirement of a non-trivial fixed point in the SU(2) sector of the weak interactions together with the requirement of the numerical unification of the gauge couplings leads to a prediction for the value of the SU(2) gauge coupling in the fixed point regime. The fixed point regime must be in the TeV region to solve the unitarity problem in the elastic scattering of W bosons. We find that the unification scale is at about 1014 GeV. Viable grand unified theories must thus conserve baryon number. We discuss how to build such a model without using Higgs bosons.


LEP data constrain severely many proposed extensions of the Standard Model. These include: massive neutrinos, which are now largely excluded as candidates for the dark matter of the Universe; supersymmetric particles, the lightest of which would still constitute detectable dark matter; technicolour, of which many favoured versions are now excluded by precision electroweak measurements; and grand unified theories, of which LEP data favour supersymmetric versions.


1993 ◽  
Vol 08 (24) ◽  
pp. 4339-4354 ◽  
Author(s):  
J.L. DIAZ CRUZ ◽  
O.A. SAMPAYO

We study the detection of the Higgs bosons predicted in the minimal SUSY standard model (h0, H0, A0 and H±). We find that after radiative corrections are considered, there is a region of parameter space where h0 will be out of the LEP reach. Some portion of this region can be covered at hadron colliders using the mechanism of associated production [Formula: see text], with h0→γγ. Other decays that may help to detect the neutral Higgses (produced either inclusively or in association with [Formula: see text]) are H→ZZ*, W+W−/ZZ, A0→Z+H0. We find that H± may be detected also through the decays H±→W±h0 and the associated production of H± with [Formula: see text].


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