Lightest CP-even Higgs Boson Mass Research Articles

The lightest Higgs boson mass of the MSSM at three-loop accuracy

In this article we provide explicit computations of the quantum corrections to the lightest CP-even Higgs Boson mass in the real version of the Minimal Supersymmetric Standard Model. We compute the contributions coming from the SUSY-QCD sector with a precision of three loops at order O(αtαs2). The renormalization procedure adopted is based on the dimensional reduction scheme in order to preserve supersymmetry to all perturbative orders. The calculation extends the region of validity of previous studies to the whole supersymmetric parameter space. The involved master integrals have been computed by exploiting new proposed approaches based on the dispersion relation techniques for the numerical calculation of three-loop vacuum integrals with arbitrary mass scales.

Least fine-tuned U(1) extended SSM

We consider the Higgs boson mass in a class of the UMSSM models in which the MSSM gauge group is extended by an additional U(1)′ group. Implementing the universal boundary condition at the GUT scale we target phenomenologically interesting regions of UMSSM where the necessary radiative contributions to the lightest CP-even Higgs boson mass are significantly small and LSP is always the lightest neutralino. We find that the smallest amount of radiative contributions to the Higgs boson mass is about 50 GeV in UMSSM, this result is much lower than that obtained in the MSSM framework, which is around 90 GeV. Additionally, we examine the Higgs boson properties in these models in order to check whether if it can behave similar to the SM Higgs boson under the current experimental constraints. We find that enforcement of smaller radiative contribution mostly restricts the U(1)′ breaking scale as vS≲10 TeV. Besides, such low contributions demand hS∼0.2–0.45. Because of the model dependency in realizing these radiative contributions θE6<0 are more favored, if one seeks for the solutions consistent with the current dark matter constraints. As to the mass spectrum, we find that stop and stau can be degenerated with the LSP neutralino in the range from 300 GeV to 700 GeV; however, the dark matter constraints restrict this scale as mt˜,mτ˜≳500 GeV. Such degenerate solutions also predict stop-neutralino and stau-neutralino co-annihilation channels, which are effective to reduce the relic abundance of neutralino down to the ranges consistent with the current dark matter observations. Finally, we discuss the effects of heavy MZ′ in the fine-tuning. Even though the radiative contributions are significantly low, the required fine-tuning can still be large. We comment about reinterpretation of the fine-tuning measure in the UMSSM framework, which can yield efficiently low results for the fine-tuning the electroweak scale.

The Light CP-Even Higgs Boson Mass of the MSSM at Three-Loop Accuracy

In this paper we are going to discuss the relevant aspects related to the calculation of the higher order corrections to the lightest CP-even Higgs boson mass of the minimal supersymmetric standard model with real parameters (rMSSM). We have computed these corrections using the Feynman diagrammatic approach with a precision of three-loop in the SUSYQCD sector. The renormalization scheme adopted in this work is based on a variant of dimensional regularization where the so called dimensional reduction is performed in order to preserve supersymmetry to all perturbative orders. The calculation will extend the region of validity of previous studies to the whole parameters space. The emerging loop integrals have been computed by exploiting new proposed approaches based on the dispersion relation techniques for the numerical calculation of three-loop vacuum integrals with arbitrary mass scales.

Reconciling EFT and hybrid calculations of the light MSSM Higgs-boson mass

Various methods are used in the literature for predicting the lightest CP-even Higgs boson mass in the Minimal Supersymmetric Standard Model (MSSM). Fixed-order diagrammatic calculations capture all effects at a given order and yield accurate results for scales of supersymmetric (SUSY) particles that are not separated too much from the weak scale. Effective field theory calculations allow a resummation of large logarithmic contributions up to all orders and therefore yield accurate results for a high SUSY scale. A hybrid approach, where both methods have been combined, is implemented in the computer code FeynHiggs. So far, however, at large scales sizeable differences have been observed between FeynHiggs and other pure EFT codes. In this work, the various approaches are analytically compared with each other in a simple scenario in which all SUSY mass scales are chosen to be equal to each other. Three main sources are identified that account for the major part of the observed differences. Firstly, it is shown that the scheme conversion of the input parameters that is commonly used for the comparison of fixed-order results is not adequate for the comparison of results containing a series of higher-order logarithms. Secondly, the treatment of higher-order terms arising from the determination of the Higgs propagator pole is addressed. Thirdly, the effect of different parametrizations in particular of the top Yukawa coupling in the non-logarithmic terms is investigated. Taking into account all of these effects, in the considered simple scenario very good agreement is found for scales above 1 TeV between the results obtained using the EFT approach and the hybrid approach of FeynHiggs.

On the two-loop corrections to the Higgs mass in trilinear R-parity violation

We study the impact of large trilinear R-parity violating couplings on the lightest CP-even Higgs boson mass in supersymmetric models. We use the publicly available computer codes SARAH and SPheno to compute the leading two-loop corrections. We use the effective potential approach. For not too heavy third generation squarks (m˜≲1 TeV) and couplings close to the unitarity bound we find positive corrections up to a few GeV in the Higgs mass.

One-parameter model for the superworld

We review the No-Scale ℱ-SU(5) model with extra TeV-scale vector-like flippon multiplets and its associated collider phenomenology in the search for supersymmetry at the LHC. The model framework possesses the rather unique capacity to provide a light CP-even Higgs boson mass in the favored 124–126 GeV window while simultaneously retaining a testably light SUSY spectrum that is consistent with emerging low-statistics excesses beyond the Standard Model expectation in the ATLAS and CMS multijet data.

Effects of neutrino inverse seesaw mechanism on the sparticle spectrum in CMSSM and NUHM2

We study the implications of the inverse seesaw mechanism (ISS) on the sparticle spectrum in the Constrained Minimal Supersymmetric Standard Model (CMSSM) and Non-Universal Higgs Model (NUHM2). Employing the maximal value of the Dirac Yukawa coupling involving the up type Higgs doublet provides a 2-3 GeV enhancement of the lightest CP-even Higgs boson mass. This effect permits one to have lighter colored sparticles in the CMSSM and NUHM2 scenarios with LSP neutralino, which can be tested at LHC14. We present a variety of LHC testable benchmark points with the desired LSP neutralino dark matter relic abundance.

High-precision predictions for the light CP-even Higgs boson mass of the minimal supersymmetric standard model.

For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FEYNHIGGS.

Higgs boson of mass 125 GeV in gauge mediated supersymmetry breaking models with matter-messenger mixing

We investigate the effects of messenger-matter mixing on the lightest CP-even Higgs boson mass m_h in gauge-mediated supersymmetry breaking models. It is shown that with such mixings m_h can be raised to about 125 GeV, even when the superparticles have sub-TeV masses, and when the gravitino has a cosmologically preferred sub-keV mass. In minimal gauge mediation without messenger-matter mixing, realizing m_h = 125 GeV would require multi-TeV SUSY spectrum. The increase in $m_h$ due to messenger-matter mixing is maximal in the case of messengers belonging to 10+\bar{10} of SU(5) unification, while it is still significant when they belong to $5+\bar{5}$ of SU(5). Our results are compatible with gauge coupling unification, perturbativity, and the unification of messenger Yukawa couplings. We embed these models into a grand unification framework with a U(1) flavor symmetry that addresses the fermion mass hierarchy and generates naturally large neutrino mixing angles. While SUSY mediated flavor changing processes are sufficiently suppressed in such an embedding, small new contributions to K^0-\bar{K^0} mixing can resolve the apparent discrepancy in the CP asymmetry parameters \sin2\beta and \epsilon_K.

Testing No-Scale [formula omitted]–[formula omitted]: A 125 GeV Higgs boson and SUSY at the [formula omitted] LHC

We celebrate the recent Higgs discovery announcement with our experimental colleagues at the LHC and look forward to the implications that this success will bring to bear upon the continuing search for supersymmetry (SUSY). The model framework named No-Scale F–SU(5) possesses the rather unique capacity to provide a light CP-even Higgs boson mass in the favored 124–126 GeV window while simultaneously retaining a testably light SUSY spectrum that is consistent with emerging low-statistics excesses beyond the Standard Model expectation in the ATLAS and CMS multijet data. In this Letter we review the distinctive F–SU(5) mechanism that forges the physical 125 GeV Higgs boson and make a specific assessment of the ATLAS multijet SUSY search observables that may be expected for a 15 fb−1 delivery of 8 TeV data in this model context. Based on our Monte Carlo study, we anticipate that the enticing hints of a SUSY signal observed in the 7 TeV data could be amplified in the 8 TeV results. Moreover, if the existing signal is indeed legitimate, we project that the rendered gains in significance will be sufficient to conclusively rule out an alternative attribution to statistical fluctuation at that juncture.

Asymmetric origin for gravitino relic density in the hybrid gravity-gauge mediated supersymmetry breaking

We propose the hybrid gravity-gauge mediated supersymmetry breaking where the gravitino mass is about several GeV. The strong constraints on supersymmetry viable parameter space from the CMS and ATLAS experiments at the LHC can be relaxed due to the heavy colored supersymmetric particles, and it is consistent with null results in the dark matter (DM) direct search experiments such as XENON100. In particular, the possible maximal flavor and CP violations from the relatively small gravity mediation may naturally account for the recent LHCb anomaly. In addition, because the gravitino mass is around the asymmetric DM mass, we propose the asymmetric origin of the gravitino relic density and solve the cosmological coincident problem on the DM and baryon densities ΩDM : Ω B ≈ 5 : 1. The gravitino relic density arises from asymmetric metastable particle (AMP) late decay. However, we show that there is no AMP candidate in the minimal supersymmetric Standard Model (SM) due to the robust gaugino/Higgsino mediated wash-out effects. Interestingly, AMP can be realized in the well motivated supersymmetric SMs with vector-like particles or continuous U(1) R symmetry. Especially, the lightest CP-even Higgs boson mass can be lifted in the supersymmetric SMs with vector-like particles.

LightestCP-even Higgs boson mass in the testable flippedSU(5)×U(1)Xmodels fromFtheory

We study the lightest CP-even Higgs boson mass in five kinds of testable flipped SU(5) x U(1)_X models from F-theory. Two kinds of models have vector-like particles around the TeV scale, while the other three kinds also have the vector-like particles at the intermediate scale that can be considered as messenger fields in gauge mediated supersymmetry breaking. We require that the Yukawa couplings for the TeV-scale vector-like particles and the third family of the Standard Model (SM) fermions are smaller than three from the electroweak scale to the SU(3)_C x SU(2)_L unification scale. With the two-loop renormalization group equation running for the gauge couplings and Yukawa couplings, we obtain the maximal Yukawa couplings between the TeV-scale vector-like particles and Higgs fields. To calculate the lightest CP-even Higgs boson mass upper bounds, we employ the renormalization group improved effective Higgs potential approach, and consider the two-loop leading contributions in the supersymmetric SM and one-loop contributions from the TeV-scale vector-like particles. We assume maximal mixings between the stops and between the TeV-scale vector-like scalars. The numerical results for these five kinds of models are roughly the same. In particular, we show that the lightest CP-even Higgs boson can have mass up to 146 GeV naturally, which is the current upper bound from the CMS and ATLAS collaborations.

Unification of dynamical determination and bare minimal phenomenological constraints in no-scaleF−SU(5)

We revisit the construction of the viable parameter space of No-Scale $\mathcal{F}\ensuremath{-}SU(5)$, a model built on the $\mathcal{F}$-lipped $SU(5)\ifmmode\times\else\texttimes\fi{}U(1{)}_{\mathrm{X}}$ gauge group, supplemented by a pair of $\mathcal{F}$-theory derived vectorlike multiplets at the TeV scale, and the dynamically established boundary conditions of No-Scale Supergravity. Employing an updated numerical algorithm and a substantially upgraded computational engine, we significantly enhance the scope, detail and accuracy of our prior study. We sequentially apply a set of ``bare-minimal'' phenomenological constraints, consisting of i) the dynamically established boundary conditions of No-Scale Supergravity, ii) consistent radiative electroweak symmetry breaking, iii) precision LEP constraints on the light supersymmetric mass content, iv) the world average top-quark mass, and v) a light neutralino satisfying the 7-year WMAP cold dark-matter relic density measurement. The overlap of the viable parameter space with key rare-process limits on the branching ratio for $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$ and the muon anomalous magnetic moment is identified as the ``golden strip'' of $\mathcal{F}\ensuremath{-}SU(5)$. A cross check for top-down theoretical consistency is provided by application of the ``Super No-Scale'' condition, which dynamically selects a pair of undetermined model parameters in a manner that is virtually identical to the corresponding phenomenological (driven primarily by the relic density) selection. The predicted vectorlike particles are candidates for production at the future LHC, which is furthermore sensitive to a distinctive signal of ultrahigh multiplicity hadronic jets. The lightest CP-even Higgs boson mass is predicted to be ${120}_{\ensuremath{-}1}^{+3.5}\text{ }\text{ }\mathrm{GeV}$, with an additional 3--4 GeV upward shift possible from radiative loops in the vectorlike multiplets. The predominantly bino flavored lightest neutralino is suitable for direct detection by the Xenon collaboration.

Natural predictions for the Higgs boson mass and supersymmetric contributions to rare processes

In the context of No-Scale F-SU(5), a model defined by the convergence of the F-lipped SU(5) Grand Unified Theory, two pairs of hypothetical TeV scale vector-like supersymmetric multiplets with origins in F-theory, and the dynamically established boundary conditions of No-Scale Supergravity, we predict that the lightest CP-even Higgs boson mass lies within the range of 119.0 GeV to 123.5 GeV, exclusive of the vector-like particle contribution to the mass. With reports by the CMS, ATLAS, CDF, and DØ Collaborations detailing enticing statistical excesses in the vicinity of 120 GeV in searches for the Standard Model Higgs boson, all signs point to an imminent discovery. While basic supersymmetric constructions such as mSUGRA and the CMSSM have already suffered overwhelming reductions in viable parameterization during the LHCʼs initial year of operation, about 80% of the original No-Scale F-SU(5) model space remains viable after analysis of the first 1.1 fb−1 of integrated luminosity. This model is moreover capable of handily explaining the small excesses recently reported in the CMS multijet supersymmetry search, and also features a highly favorable “golden” subspace which may simultaneously account for the key rare process limits on the muon anomalous magnetic moment (g−2)μ and the branching ratio of the flavor-changing neutral current decay b→sγ. In addition, the isolated mass parameter responsible for the global particle mass normalization, the gaugino boundary mass M1/2, is dynamically determined at a secondary local minimization of the minimum of the Higgs potential Vmin, in a manner which is deeply consistent with all precision measurements at the physical electroweak scale.

General gauge and anomaly mediated supersymmetry breaking in grand unified theories with vector-like particles

In Grand Unified Theories (GUTs) from orbifold and various string constructions the generic vector-like particles do not need to form complete SU(5) or SO(10) representations. To realize them concretely, we present orbifold SU(5) models, orbifold SO(10) models where the gauge symmetry can be broken down to flipped SU(5) X U(1)_X or Pati-Salam SU(4)_C X SU(2)_L X SU(2)_R gauge symmetries, and F-theory SU(5) models. Interestingly, these vector-like particles can be at the TeV-scale so that the lightest CP-even Higgs boson mass can be lifted, or play the messenger fields in the Gauge Mediated Supersymmetry Breaking (GMSB). Considering GMSB, ultraviolet insensitive Anomaly Mediated Supersymmetry Breaking (AMSB), and the deflected AMSB, we study the general gaugino mass relations and their indices, which are valid from the GUT scale to the electroweak scale at one loop, in the SU(5) models, the flipped SU(5) X U(1)_X models, and the Pati-Salam SU(4)_C X SU(2)_L X SU(2)_R models. In the deflected AMSB, we also define the new indices for the gaugino mass relations, and calculate them as well. Using these gaugino mass relations and their indices, we may probe the messenger fields at intermediate scale in the GMSB and deflected AMSB, determine the supersymmetry breaking mediation mechanisms, and distinguish the four-dimensional GUTs, orbifold GUTs, and F-theory GUTs.

Flipped [formula omitted] models from F-theory

We systematically construct flipped SU ( 5 ) × U ( 1 ) X models without and with bulk vector-like particles from F-theory. To realize the decoupling scenario, we introduce sets of vector-like particles in complete SU ( 5 ) × U ( 1 ) multiplets at the TeV scale, or at the intermediate scale, or at the TeV scale and high scale. To avoid the Landau pole problem for the gauge couplings, we can only introduce five sets of vector-like particles around the TeV scale. These vector-like particles can couple to the Standard Model singlet fields, and obtain suitable masses by Higgs mechanism. We study gauge coupling unification in detail. We show that the U ( 1 ) X flux contributions to the gauge couplings preserve the SU ( 5 ) × U ( 1 ) X gauge coupling unification. We calculate the SU ( 3 ) C × SU ( 2 ) L unification scales, and the SU ( 5 ) × U ( 1 ) X unification scales and unified couplings. In most of our models, the high-scale or bulk vector-like particles can be considered as string-scale threshold corrections since their masses are close to the string scale. Furthermore, we discuss the phenomenological consequences of our models. In particular, in the models with TeV-scale vector-like particles, the vector-like particles can be observed at the Large Hadron Collider, the proton decay is within the reach of the future Hyper-Kamiokande experiment, the lightest CP-even Higgs boson mass can be increased, the hybrid inflation can be naturally realized, and the correct cosmic primordial density fluctuations can be generated.

High precision calculations within the MSSM

In this talk we report on two recent high precision calculations within the minimal supersymmetric extension of the Standard Model. In the first part of the talk we present the computation of the light CP-even Higgs boson mass with three-loop accuracy, taking into account the next-to-next-to-leading order effects from supersymmetric Quantum Chromodynamics. Furthermore, we discuss a consistent evolution of the strong coupling constant α s from M Z to the GUT scale, involving three-loop running and two-loop decoupling. For both observables the numerical results amount to corrections of the same order as the current experimental accuracy or that expected at the CERN Large Hadron Collider (LHC).

String inspired singlet extensions of the minimal supersymmetric Standard Model

The only allowed Higgs superpotential term at stringy tree level in the string derived Singlet Extensions of the Minimal Supersymmetric Standard Model (SEMSSM) is h S H d H u , which leads to an additional global U ( 1 ) symmetry in the Higgs potential. We propose the string inspired SEMSSM where the global U ( 1 ) symmetry is broken by the additional superpotential terms or supersymmetry breaking soft terms that can be obtained naturally due to the instanton effects or anomalous U ( 1 ) A gauge symmetry. In these models, we can solve the μ problem and the fine-tuning problem for the lightest CP-even Higgs boson mass in the MSSM, generate the baryon asymmetry via electroweak baryogenesis, and predict the new Higgs physics which can be tested at the LHC and ILC.

Production and decays of supersymmetric Higgs bosons in spontaneously brokenRparity

We study the mass spectra, production and decay properties of the lightest supersymmetric CP-even and CP-odd Higgs bosons in models with spontaneously broken R-parity (SBRP). We compare the resulting mass spectra with expectations of the Minimal Supersymmetric Standard Model (MSSM), stressing that the model obeys the upper bound on the lightest CP-even Higgs boson mass. We discuss how the presence of the additional scalar singlet states affects the Higgs production cross sections, both for the Bjorken process and the "associated production". The main phenomenological novelty with respect to the MSSM comes from the fact that the spontaneous breaking of lepton number leads to the existence of the majoron, denoted J, which opens new decay channels for supersymmetric Higgs bosons. We find that the invisible decays of CP-even Higgses can be dominant, while those of the CP-odd bosons may also be sizeable.

Electroweak precision observables: two-loop Yukawa corrections of supersymmetric particles

The dominant electroweak two-loop corrections to the precision observables M_W and s_w^eff are calculated in the MSSM. They are obtained by evaluating the two-loop Yukawa contributions of O(alpha_t^2), O(alpha_t alpha_b), O(alpha_b^2) to the quantity Delta rho. The result, involving the contributions from Standard Model fermions, sfermions, Higgs bosons and higgsinos, is derived in the gauge-less limit for arbitrary values of the lightest CP-even Higgs boson mass. A thorough discussion of the parameter relations enforced by supersymmetry is given, and two different renormalization schemes are applied. Compared to the previously known result for the quark-loop contribution we find a shift of up to +8 MeV in M_W and -4 * 10^-5 in s_w^eff. Detailed numerical estimates of the remaining uncertainties of M_W and s_w^eff from unknown higher-order contributions are obtained for different values of the supersymmetric mass scale.