Leone Cavicchia
We study the generic NMSSM with the coupling λS H_1 H_2 at the limit of perturbativity, λ~0.7-0.8, and a moderate stop mass, m_{\tilde{t}} < 300 GeV. Respecting the LEP2 bounds and insisting on naturalness, we delimit the allowed region of parameter space and we study the spectrum and phenomenology of the relatively light new particles.
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We compute the full next-to-leading order supersymmetric (SUSY) electroweak (EW) and SUSY-QCD corrections to the decays of CP-odd NMSSM Higgs bosons into stop pairs. In our numerical analysis we also present the decay of the heavier stop into the lighter stop and an NMSSM CP-odd Higgs boson. Both the EW and the SUSY-QCD corrections are found to be significant and have to be taken into account for a proper prediction of the decay widths.
In this work, we study the constraints on the scenario of light stops and sbottoms in the next-to-minimal supersymmetric standard model (NMSSM), especially by a 125 GeV Higgs boson discovery and the LHC bounds on supersymmetry. The constraints from dark matter detections are also taken into account. From the parameter scan, we find that the NMSSM can well accommodate a light Higgs boson around 125 GeV and decay patterns. We would like to stress that the LHC direct supersymmetry searches with b-tagging are very powerful and can set strong bounds on many NMSSM parameter points with light stops a…
Higgs signatures from the cascade decays of light stops are an interesting possibility in the next to minimal supersymmetric standard model (NMSSM). We investigate the potential reach of the light stop mass at the 13 TeV run of the LHC by means of five NMSSM benchmark points where this signature is dominant. These benchmark points are compatible with current Higgs coupling measurements, LHC constraints, dark matter relic density and direct detection constraints. We consider single and di-lepton search strategies, as well as the jet-substructure technique to reconstruct the Higgs bosons. We fin…
We study the viability of having two relatively light top squarks (`stops') in the framework of the Next-to-Minimal Supersymmetric Standard Model (NMSSM). Such light stops render the NMSSM rather `natural'. These are shown to be allowed by the relevant direct searches at the Large Hadron Collider (LHC) and to be compatible with the latest LHC results on the Higgs sector, other low energy electroweak constraints and recent constraints from the dark matter (DM) sector. We propose dedicated searches for such light stops at the LHC within a `simplified' scenario that may have a bino-like or a sing…
We study the next-to-minimal supersymmetric standard model with the TeV scale mirage mediation. The 125 GeV Higgs boson mass is realized with O(10)% tuning for 1.5 TeV gluino and 1TeV stop masses.
A consistent interpretation of the Higgs data requires the same precision in the Higgs boson masses and in the trilinear Higgs self-couplings, which are related through their common origin from the Higgs potential. In this work we provide the two-loop corrections at order ${\cal O}(α_t α_s)$ in the approximation of vanishing external momenta to the trilinear Higgs self-couplings in the CP-violating Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM). In the top/stop sector two different renormalization schemes have been implemented, the OS and the $\overline{\text{DR}}$ sche…
We examine the use of modified Higgs sectors to address the little hierarchy problem of supersymmetry. Such models reduce weak-scale fine-tuning by allowing lighter stops, but they retain some fine-tuning independent of the Higgs. The modified Higgs sector can also introduce model-dependent tunings. We consider the model-independent constraints on naturalness from squark, gluino, chargino and neutralino searches, as well as the model-dependent tuning in the PQ- and R-symmetric limits of the NMSSM, where cascade decays or additional quartic interactions can hide a Higgs without relying on heavy…
The recent LHC discovery of a Higgs-like resonance at 126 GeV suggests that the minimal supersymmetric standard model must be modified in order to preserve naturalness. A simple extension is to include a singlet superfield and consider the scale-invariant NMSSM, whose renormalizable superpotential contains no dimensionful parameters. This extension not only solves the μ-problem, but can easily accommodate a 126 GeV Higgs. We study the naturalness of the scale-invariant NMSSM taking into account the recent constraints from LHC searches, flavor physics and electroweak precision tests. We show th…
Relatively light stops in gauge mediation models are usually made compatible with the Higgs mass of 125 GeV by introducing direct Higgs-messenger couplings. We show that such couplings are not necessary in a simple and predictive model that combines minimal gauge mediation and the next-to-minimal supersymmetric standard model (NMSSM). We show that one can obtain a 125 GeV Standard Model-like Higgs boson with stops as light as 1.1 TeV, thanks to the mixing of the Higgs with a singlet state at ${\cal O}(90-100)$ GeV that can explain the LEP excess. In this scenario the singlet-higgs-higgs superf…
Can supersymmetric models with a moderate stop mass be made consistent with the negative Higgs boson searches at LEP, while keeping perturbative unification manifest? The NMSSM achieves this rather easily, but only if extra matter multiplets filling complete SU(5) representations are present at intermediate energies. As a concrete example which makes use of this feature, we give an analytic description of the phenomenology of a constrained NMSSM close to a Peccei-Quinn symmetry point. The related pseudo-Goldstone boson appears in decays of the Higgs bosons and possibly of the lightest neutrali…
In this talk I discuss some aspects of the phenomenology of a moderately light charged Higgs ($H^\pm$) with a mass $\gts 130$ GeV, lighter than the top quark, at the LHC. A charged Higgs in this mass range is still allowed in next-to-minimal Supersymmetric Standard Model (NMSSM) at low $\tan β$ as well as in CP-violating (\cp) Minimal Supersymmetric Standard Model (MSSM) for a certain choice of \cp parameters, still respecting all the LEP-II bounds. In both the cases, the $H^\pm$ has a large branching ratio in the $W^\pm ϕ$ channel, where $ϕ$ denotes a generic Higgs which is dominantly pseudos…
We study the phenomenology of Higgs bosons close to 126 GeV within the scale invariant unconstrained next-to-minimal supersymmetric Standard Model (NMSSM), focusing on the regions of parameter space favoured by low fine-tuning considerations, namely stop masses of order 400 GeV to 1 TeV and an effective $μ$ parameter between 100-200 GeV, with large (but perturbative) $λ$ and low $\tan β=$2-4. We perform scans over the above parameter space, focusing on the observable Higgs cross sections into $γγ$, $WW$, $ZZ$, $bb$, $ττ$ final states, and study the correlations between these observables. We sh…
We consider extensions of the next-to-minimal supersymmetric model (NMSSM) in which the observed neutrino masses are generated through a TeV scale inverse seesaw mechanism. The new particles associated with this mechanism can have sizable couplings to the Higgs field which can yield a large contribution to the mass of the lightest CP-even Higgs boson. With this new contribution, a 126 GeV Higgs is possible along with order of 200 GeV masses for the stop quarks for a broad range of \tanβ. The Higgs production and decay in the diphoton channel can be enhanced due to this new contribution. It is …
The recent LHC indications of a SM-like Higgs boson near 125 GeV are consistent not only with the Standard Model (SM) but also with Supersymmetry (SUSY). However naturalness arguments disfavour the Minimal Supersymmetric Standard Model (MSSM). We consider the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with a SM-like Higgs boson near 125 GeV involving relatively light stops and gluinos below 1 TeV in order to satisfy naturalness requirements. We are careful to ensure that the chosen values of couplings do not become non perturbative below the grand unification (GUT) scale, although w…
We study the NMSSM with universal Susy breaking terms (besides the Higgs sector) at the GUT scale. Within this constrained parameter space, it is not difficult to find a Higgs boson with a mass of about 125 GeV and an enhanced cross section in the diphoton channel. An additional lighter Higgs boson with reduced couplings and a mass <123 GeV is potentially observable at the LHC. The NMSSM-specific Yukawa couplings lambda and kappa are relatively large and tan(beta) is small, such that lambda, kappa and the top Yukawa coupling are of order 1 at the GUT scale. The lightest stop can be as light as…
It is pointed out that mixing effects in the CP-even scalar sector of the NMSSM can give 6-8 GeV correction to the SM-like Higgs mass in moderate or large $\tanβ$ regions with a small value of the singlet-higgs-higgs superfields coupling $λ\sim\mathcal{O}(0.1)$. This effect comes mainly from the mixing of the SM-like Higgs with lighter singlet. In the same parameter range, the mixing of the heavy doublet Higgs with the singlet may strongly modify the couplings of the singlet-like and the 125 GeV scalars. Firstly, the LEP bounds on a light singlet can be evaded for a large range of its masses. …
The natural supersymmetry (SUSY) requires that stop, sbottom, and gluino be around one TeV or lighter. By using the direct SUSY search bounds from both ATLAS and CMS Collaborations, we examine the constraints on the natural SUSY in the Next to Minimal Supersymmetric Standard Model (NMSSM). We consider two cases of interpretations for the Higgs boson data: (1) the Standard Model (SM) like Higgs boson is the lightest CP-even Higgs boson; (2) the SM like Higgs boson is the second lightest CP-even Higgs boson. We find that the direct SUSY searches at the LHC impose a strong constraint on the light…
The Next to Minimal Supersymmetric Standard Model (NMSSM) with a Higgs-singlet coupling λ close to unity, moderate tan β and stop masses below 1 TeV minimizes the fine tuning of the electroweak scale, making possible that the lightest new particles, except perhaps for the LSP, be part of the extended Higgs system. We show how the measurements of the couplings of the 126 GeV Higgs boson constrain the region of the physical parameters of a generic NMSSM most relevant to this context. In the same region of parameter space we determine the cross section for the production of a heavier CP-even scal…
In this work, we present mass limits on gluinos and stops in a natural Next-to-Minimal Supersymmetric Standard Model (NMSSM) with a singlino as the lightest supersymmetric particle. Motivated by naturalness, we consider spectra with light higgsinos, sub-TeV third generation sparticles and gluinos well below the multi-TeV regime while the electroweak gauginos, the sleptons and the first and second generation squarks are decoupled. We check that our natural supersymmetry spectra satisfy all electroweak precision observables and flavour measurements as well as theoretical constraints. By reinterp…
We study a gauge mediated supersymmetry breaking version of the NMSSM in which the soft m_{H_u}^2 and m_{H_d}^2 masses receive extra contributions due to the presence of direct couplings between the Higgs and the messenger sector. We are motivated by the well-known result that minimal gauge mediation is phenomenologically incompatible with the NMSSM due to the small value of the induced effective mu term. The model considered in the present paper solves the aforementioned problem through a modified RG running of the singlet soft mass m_N^2. This effect, which is induced by the dominant m_{H_d}…
Application of the 3-Loop FlexibleEFTHiggs Method to the MSSM and the NMSSM
基于三环FlexibleEFTHiggs混合计算，分析了MSSM中轻CP-even Higgs玻色子极点质量及其参数依赖性，并改进了NMSSM中的Higgs质量计算。
In this work we investigate the Higgs pair production in the MSSM and NMSSM at the photon-photon collision of the ILC. We consider various experimental constraints and scan over the parameter space of the MSSM and NMSSM. Then we calculate the cross section of Higgs pair production in the allowed parameter space and compare the results with the predictions in the SM. We find that the large enhancement of the cross section in the MSSM is mainly due to the contributions from the loops mediated by the stau, while in the NMSSM it is mainly due to the contributions from the top-squark loops. For lig…
We examine the implications of singlet-doublet Higgs mixing on the properties of a Standard Model (SM)-like Higgs boson within the Peccei-Quinn invariant extension of the NMSSM (PQ-NMSSM). The SM singlet added to the Higgs sector connects the PQ and visible sectors through a PQ-invariant non-renormalizable Kähler potential term, making the model free from the tadpole and domain-wall problems. For the case that the lightest Higgs boson is dominated by the singlet scalar, the Higgs mixing increases the mass of a SM-like Higgs boson while reducing its signal rate at collider experiments compared …
We discuss the impact of the two-loop corrections to the Higgs mass in the NMSSM beyond $O(α_S(α_b + α_t))$. For this purpose we use the combination of the public tools SARAH and SPheno to include all contributions stemming from superpotential parameters. We show that the corrections in the case of a heavy singlet are often MSSM-like and reduce the predicted mass of the SM-like state by about 1 GeV as long as $λ$ is moderately large. For larger values of $λ$ the additional corrections can increase the SM-like Higgs mass. If a light singlet is present the additional corrections become more impo…
The recent discovery of a Higgs-like boson at the LHC with a mass of 126 GeV has revived the interest in supersymmetric models, which predicted a Higgs boson mass below 130 GeV long before its discovery. We compare systematically the allowed parameter space in the constrained Minimal Supersymmetric Standard Model (CMSSM) and the Next-to-Minimal Supersymmetric Model (NMSSM) by minimizing the chi^2 function with respect to all known constraints from accelerators and cosmology using GUT scale parameters. For the CMSSM the Higgs boson mass at tree level is below the Z^0 boson mass and large radiat…
We study a region in the NMSSM parameter space in which the mass of the SM-like Higgs boson is uplifted by ~4-17 GeV, allowing for stop masses and |A_t| <= 1 TeV alleviating the little fine tuning problem of the MSSM. An uplift of the mass of the SM-like Higgs boson is possible in two distinct regions in the NMSSM parameter space: Either for large lambda and small tan(beta) or, through singlet-doublet mixing, for small lambda and large tan(beta). For a mostly singlet-like Higgs state H_S with a mass below 125 GeV we investigate possible direct or indirect search channels at the run II of the L…
We explore the effects of Higgs mixing in the general next-to-minimal supersymmetric Standard Model (NMSSM). Extended to include a gauge singlet, the Higgs sector can naturally explain the observed Higgs boson mass in TeV scale supersymmetry without invoking large stop mixing. This is particularly the case when the singlet scalar is light so that singlet-doublet mixing increases the mass of the SM-like Higgs boson. In such a case the Higgs mixing has interesting implications following from the fact that the higgsino mass parameter and the singlet coupling to Higgs bilinear crucially depend on …
We study whether a 125 GeV standard model-like Higgs boson can be accommodated within the scale-invariant NMSSM in a way that is natural in all respects, i.e., not only is the stop mass and hence its loop contribution to Higgs mass of natural size, but we do not allow significant tuning of NMSSM parameters as well. We pursue as much as possible an analytic approach which gives clear insights on various ways to accommodate such a Higgs mass, while conducting complementary numerical analyses. We consider both scenarios with singlet-like state being heavier and lighter than SM-like Higgs. With A-…
The LHC discovered the Standard Model (SM) like Higgs boson with mass around 125 GeV. However, there exist hints of deviations from Higgs decays. Including the Tevatron data, the deviations can be explained by the extremely mixed stop sector in the sense of best global fit (BGF). We analyze the relations among the competing reduced coupling hGG, Higgs boson mass,and LHC stop mass m_{\wt t_1} lower bound at the tree- and one-loop level. In particular, we point out that we use the light stop running mass in the Higgs boson mass calculation while the light stop pole mass in the Higgs decays. So t…
We present our computation of the ${\cal O}((α_t+α_λ+α_κ)^2)$ two-loop corrections to the Higgs boson masses of the CP-violating Next-to-Minimal Supersymmetric Standard Model (NMSSM) using the Feynman-diagrammatic approach in the gaugeless limit at vanishing external momentum. We choose a mixed $\overline{\mbox{DR}}$-on-shell (OS) renormalisation scheme for the Higgs sector and apply both $\overline{\mbox{DR}}$ and OS renormalisation in the top/stop sector. For the treatment of the infrared divergences we apply and compare three different regularisation methods: the introduction of a regulator…
We propose that the TeV scale mirage mediation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is a novel solution for the little hierarchy problem in supersymmetry. The 125 GeV Higgs boson can be accommodated with the new quartic coupling or the mixing with the singlet. The fine-tuning measures are estimated numerically and found as low as 10\% or below for $1.5$ TeV gluino and $1$ TeV stop. The higgsino can be as heavy as 500 GeV without deteriorating the fine-tuning. An undesirable singlet-doublet mixing in the Higgs sector is suppressed due to approximate scale symmetries. We …
We study the next-to-minimal supersymmetric standard model. We consider soft supersymmetry breaking parameters, which are induced by the mirage mediation mechanism of supersymmetry breaking. We concentrate on the mirage mediation, where the so-called mirage scale is the TeV scale. In this scenario, we can realize the up-type Higgs soft mass of O(200) GeV, while other masses such as gaugino masses and stop masses are heavy such as 1 TeV or more. Cancellation between the effective μ-term and the down-type Higgs soft mass ameliorates the fine-tuning in the electroweak symmetry breaking even for μ…
We perform a systematic study of radiative corrections to the masses of the Higgs bosons in the minimal supersymmetric standard model (MSSM) augmented by a single gauge singlet, the so-called next-to-minimal supersymmetric standard model (NMSSM). Our method is based on the one-loop effective potential and includes effects of top quark, squark, Higgs and Higgsino loops. We discuss the renormalisation group flows of Yukawa couplings and the upper bound on the lightest CP-even neutral Higgs boson mass as a function of the heavier stop mass and top mass. We then give a general discussion of Higgs …
In light of the recent LHC Higgs search data, we investigate the pair production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We first scan the parameter space of each model by considering various experimental constraints, and then calculate the Higgs pair production rate in the allowed parameter space. We find that in most cases the dominant contribution to the Higgs pair production comes from the gluon fusion process and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction (even for a TeV-scale stop the production rate can still be e…
The Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) with a Higgs boson of mass 125 GeV can be compatible with stop masses of order of the electroweak scale, thereby reducing the degree of fine-tuning necessary to achieve electroweak symmetry breaking. Moreover, in an attractive region of the NMSSM parameter space, corresponding to the "alignment limit" in which one of the neutral Higgs fields lies approximately in the same direction in field space as the doublet Higgs vacuum expectation value, the observed Higgs boson is predicted to have Standard-Model-like properties. …
There could be another scalar in nature quasi-degenerate with the observed one (h125). This is possible in models such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The scenario(s) with a single Higgs boson can be compared to that with multiple ones, all near 125 GeV. In order to assess the extent to which the current set of collider, cold dark matter relic density and direct detection limits are capable of discriminating these scenarios, we perform, for the first-time, global fits of a weak-scale phenomenological NMSSM with 26 free parameters using the nested sampling implemen…
The publicly available spectrum generators for the NMSSM often lead to different predictions for the mass of the standard model-like Higgs boson even if using the same renormalization scheme and two-loop accuracy. Depending on the parameter point, the differences can exceed 5 GeV, and even reach 8 GeV for moderate superparticle masses of up to 2 TeV. It is shown here that these differences can be traced back to the calculation of the running standard model parameters entering all calculations, to the approximations used in the two-loop corrections included in the different codes, and to differ…
To explain all the available experimental results, we have proposed the Electroweak Supersymmetry (EWSUSY) previously, where the squarks and/or gluino are heavy around a few TeVs while the sleptons, sneutrinos, Bino, Winos, and/or Higgsinos are light within one TeV. In the Next to Minimal Supersymmetric Standard Model (NMSSM), we perform the systematic χ^2 analyses on parameter space scan for three EWSUSY scenarios: (I) R-parity conservation and one dark matter candidate; (II) R-parity conservation and multi-component dark matter; (III) R-parity violation. We obtain the minimal χ^2/(degree of …
Deconstructing resonant Higgs pair production at the LHC: effects of coloured and neutral scalars in the NMSSM test case
本研究以NMSSM为测试案例，分析LHC上类SM希格斯对共振产生中有色与中性标量带来的干涉效应，通过振幅分解提取新物理特征，并给出具有潜在可观测信号的基准点。
We study the next-to-minimal supersymmetric standard model (NMSSM) with the TeV scale mirage mediation, which is known as a solution for the little hierarchy problem in supersymmetry. Our previous study showed that 125 GeV Higgs boson is realized with O(10) % fine-tuning for 1.5 TeV gluino (1 TeV stop) mass. The $μ$ term could be as large as 500 GeV without sacrificing the fine-tuning thanks to a cancellation mechanism. The singlet-doublet mixing is suppressed by $\tanβ$. In this paper, we further extend this analysis. We argue that approximate scale symmetries play a role behind the suppressi…
It is well known that excessively heavy supersymmetric particles (sparticles) are disfavored to explain the $(g-2)_μ$ anomaly, but some people overlook that moderately light sparticles are also disfavored by the LHC probes of supersymmetry. We take the Next-to-Minimal Supersymmetric Standard Model as an example to emphasize the latter point. It is found that, if the theory is required to explain the anomaly at $2σ$ level and meanwhile keep consistent with the LHC results, the following lower bounds may be set: $\tan β\gtrsim 20$, $|M_1| \gtrsim 275~{\rm GeV}$, $M_2 \gtrsim 300~{\rm GeV}$, $μ\g…
Precision measurements of the 125 GeV Higgs resonance recently discovered at the LHC have determined that its properties are similar to the ones of the Standard Model (SM) Higgs boson. However, the current uncertainties in the determination of the Higgs boson couplings leave room for significant deviations from the SM expectations. In fact, if one assumes no correlation between the top-quark and gluon couplings to the Higgs, the current global fit to the Higgs data lead to central values of the Higgs couplings to the bottom-quark and the top-quark that are about 2 $σ$ away from the SM predicti…
The ${\cal O}(α_t+α_λ+α_κ)^2$ Correction to the $ρ$ Parameter and its Effect on the W Boson Mass Calculation in the Complex NMSSM
本文在CP破坏的NMSSM中计算了ρ参数至双圈阶$\mathcal{O}(α_t+α_λ+α_κ)^2$的修正并用于W玻色子质量预言，发现双圈效应为次主导，且方案不确定性显著降低，结果已集成至NMSSMCALC程序。
The semi-constrained NMSSM (scNMSSM) extends the MSSM by a singlet field, and requires unification of the soft SUSY breaking terms in the squark and slepton sectors, while it allows that in the Higgs sector to be different. We try to interpret the muon g-2 in the scNMSSM, under the constraints of 125 GeV Higgs data, B physics, searches for low and high mass resonances, searches for SUSY particles at the LHC, dark matter relic density by WMAP/Planck, and direct searches for dark matter by LUX, XENON1T, and PandaX-II. We find that under the above constraints, the scNMSSM can still (i) satisfy mu…
We present the first global analysis of the Constrained NMSSM that investigates the impact of the recent discovery of a 126 GeV Higgs-like boson, of the observation of a signal for BR(B_s->μ^+μ^-), and of constraints on supersymmetry from ~5/fb of data accumulated at the LHC, as well as of other relevant constraints from colliders, flavor physics and dark matter. We consider three possible cases, assuming in turn that the discovered Higgs boson is: i) the lightest Higgs boson of the model; ii) the next-to-lightest Higgs boson; and iii) a combination of both roughly degenerate in mass. The like…
We compute the tuning in supersymmetric models associated with the constraints from collider measurements of the Higgs couplings to fermions and gauge bosons. In supersymmetric models, a CP-even state with SM Higgs couplings mixes with additional, heavier CP-even states, causing deviations in the Higgs couplings from SM values. These deviations are reduced as the heavy states are decoupled with large soft masses, thereby exacerbating the tuning associated with the electroweak scale. This new source of tuning is different from that derived from collider limits on stops, gluinos and Higgsinos. I…
An effective theory approach is used to compute analytically the radiative corrections to the mass of the light Higgs boson of the Minimal Supersymmetric Standard Model when there is a hierarchy in the masses of the stops (M_st1 >> M_st2 >> M_top, with moderate stop mixing). The calculation includes up to two-loop leading and next-to-leading logarithmic corrections dependent on the QCD and top-Yukawa couplings, and is further completed by two-loop non-logarithmic corrections extracted from the effective potential. The results presented disagree already at two-loop-leading-log level with widely…
In the Minimal Supersymmetric Standard Model (MSSM), a Higgs boson mass of 125 GeV can be obtained with moderately heavy scalar top superpartners provided they are highly mixed. The source of this mixing, a soft trilinear stop-stop-Higgs coupling, can result in the appearance of charge- and color-breaking minima in the scalar potential of the theory. If such a vacuum exists and is energetically favorable, the Standard Model-like vacuum can decay to it via quantum tunnelling. In this work we investigate the conditions under which such exotic vacua arise, and we compute the tunnelling rates to t…
Electroweak baryogenesis is an attractive scenario for the generation of the baryon asymmetry of the universe as its realization depends on the presence at the weak scale of new particles which may be searched for at high energy colliders. In the MSSM it may only be realized in the presence of light stops, and with moderate or small mixing between the left- and right-handed components. Consistency with the observed Higgs mass around 125 GeV demands the heavier stop mass to be much larger than the weak scale. Moreover the lighter stop leads to an increase of the gluon-gluon fusion Higgs product…
We generalize the analytical expressions for the two-loop leading-log neutral Higgs boson masses and mixing angles to the case of general left- and right-handed soft supersymmetry breaking stop and sbottom masses and left--right mixing mass parameters ($m_Q, m_U, m_D, A_t, A_b$). This generalization is essential for the computation of Higgs masses and couplings in the presence of light stops. At high scales we use the minimal supersymmetric standard model effective potential, while at low scales we consider the two-Higgs doublet model (renormalization group improved) effective potential, with …
A light stop around the weak scale is a hopeful messenger of natural supersymmetry (SUSY), but it has not shown up at the current stage of LHC. Such a situation raises the question of the fate of natural SUSY. Actually, a relatively light stop can easily be hidden in a compressed spectra such as mild mass degeneracy between stop and neutralino plus top quark. Searching for such a stop at the LHC is a challenge. On the other hand, in terms of the argument of natural SUSY, other members in the stop sector, including a heavier stop $\tilde{t}_2$ and lighter sbottom $\tilde{b}_1$ (both assumed to …
The lighter mass eigenstate ($\widetilde{t}_1$) of the two top squarks, the scalar superpartners of the top quark, is extremely difficult to discover if it is almost degenerate with the lightest neutralino ($\widetildeχ_1^0$), the lightest and stable supersymmetric particle in the R-parity conserving supersymmetry. The current experimental bound on $\widetilde{t}_1$ mass in this scenario stands only around 200 GeV. For such a light $\widetilde{t}_1$, the heavier top squark ($\widetilde{t}_2$) can also be around the TeV scale. Moreover, the high value of the higgs ($h$) mass prefers the left an…
The BMSSM framework is an effective theory approach that encapsulates a variety of extensions beyond the MSSM with which it shares the same field content. The lightest Higgs mass can be much heavier than in the MSSM without creating a tension with naturalness or requiring superheavy stops. The phenomenology of the Higgs sector is at the same time much richer. We critically review the properties of a Higgs with mass around 125GeV in this model. In particular, we investigate how the rates in the important inclusive 2 photons channel, the 2 photons + 2 jets and the ZZ to 4 leptons (and/or WW) can…
In the decoupling limit, $M^2_{A^0} \gg M^2_Z$, the heavy CP-even, CP-odd and charged Higgs boson masses are nearly degenerate, $\sin(β-α)$ approaches 1, and the lightest CP-even Higgs boson almost displays the same properties as the Standard Model Higgs boson. But the stop and sbottom sector can change this pattern through radiative corrections. We find that there are parameter regions at small, moderate and large $\tanβ$ in MSSM under experimental constraints of $(g-2)_μ$ and $b\to sγ$, where $\sin^2(β-α)$ is damped (say below 0.8), which has a significant effect on Higgs couplings $g_{h^0VV…
We present a simple supersymmetric model of split families consistent with flavor limits that preserves the successful prediction of gauge coupling unification and naturally accounts for the Higgs mass. The model provides an intricate connection between the Standard Model flavor hierarchy, supersymmetric flavor problem, unification and the Higgs mass. In particular unification favors a naturally large Higgs mass from D-term corrections to the quartic couplings in the Higgs potential. The unification scale is lowered with a stable proton that can account for the success of b-tau Yukawa coupling…
It is challenging to explain the tentative 125 GeV Higgs signal in the Minimal Supersymmetric Standard Model (MSSM) without introducing excessive fine-tuning, and this motivates the study of non-minimal implementations of low energy supersymmetry (SUSY). A term λSH_uH_d involving a Standard Model (SM) singlet state S leads to an additional source for the quartic interaction raising the mass of the lightest SM-like Higgs. However, in order to achieve m_h \approx 125 GeV with light stops and small stop mixing, it is necessary for λ\gtrsim 0.7 and consequently λmay become non-perturbative before …
In simple SO(10) SUSY GUTs the top, bottom and tau Yukawa couplings unify at the GUT scale. A naive renormalization group analysis, neglecting weak scale threshold corrections, leads to moderate agreement with the low energy data. However it is known that intrinsically large threshold corrections proportional to $\tanβ\sim m_t(M_Z)/m_b(M_Z) \sim 50$ can nullify these $t, b$, $τ$ mass predictions. In this paper we turn the argument around. Instead of predicting fermion masses, we use the constraint of Yukawa unification and the observed values $M_t, m_b(m_b), M_τ$ to constrain SUSY parameter sp…
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