Exploring SUSY light Higgs boson scenarios via dark matter experiments
Debottam Das, Andreas Goudelis, Yann Mambrini
备注：
31 pages, 5 figures. Indirect detection statistical method changed, direct detection analysis enriched, references added, main conclusions unchanged but extended. Version to appear on JCAP
We examine the dark matter phenomenology in supersymmetric light higgs boson scenarios, adapting nonuniversal Higgs masses at the gauge coupling unification scale. The correct relic density is obtained mostly through the annihilation into a pseudoscalar $A$, which gives high values for the self-annihilation cross-section at present times. Our analysis shows that most part of the $A$ pole region can produce detectable gamma-rays and antiproton signals, and still be compatible with with recent direct detection data from XENON100 and CDMS-II.
Theoretical overview on phenomenology of Higgs boson and SUSY Higgs boson at a future linear collider experiment is given as a Higgs and SUSY Higgs working group summary report for LCWS 2000.
We consider an extended Higgs sector that arises as a low-energy description of a strongly-coupled SUSY gauge theory. This model predicts the presence of extra superfields that couple with the Higgs superfields through large coupling constants. Large radiative corrections involving the extra fields can realize strongly first order electroweak phase transition, which is a vital requirement for electroweak baryogenesis scenario. At the same time, the large radiative corrections lead to significant deviations in the Higgs boson triple coupling and Higgs-to-diphoton branching ratio, which are test…
Under the expectation that nature is natural, we extend the Standard Model to include SUSY to stabilize the electroweak sector and PQ symmetry to stabilize the QCD sector. Then natural SUSY arises from a Kim-Nilles solution to the SUSY mu problem which allows for a little hierarchy where mu ~ f_a^2/M_P ~ 100-300 GeV while the SUSY particle mass scale m(SUSY)~ 1-10 TeV >> mu. Dark matter then consists of two particles: a higgsino-like WIMP and a SUSY DFSZ axion. The range of allowed axion mass values m(axion) depends on the mixed axion-higgsino relic density. The range of m(axion) is actually r…
Interesting contributions to $Δa_μ$ from a two-Higgs-doublet-model is coming from a two-loop Barr-Zee diagram for most part of the parameter space -- a fact that has been overlooked by some Higgs/SUSY experts. A definite positive contribution has requirements that go against precision EW data and other known constraints. For the case without SUSY, in particular, this is almost enough to kill the two-Higgs-doublet-model (II). We will discuss the interplay of all the constraints and their implications.
The discovery of the Standard Model (SM) or supersymmetric (SUSY) Higgs bosons belongs to the main endeavors of the Large Hadron Collider (LHC). In this article the status of the signal and background calculations for Higgs boson production at the LHC is reviewed.
We construct a calculable model of electroweak symmetry breaking in which the Higgs doublet emerges from the meta-stable SUSY breaking sector as a pseudo Nambu-Goldstone boson. The Higgs boson mass is further protected by the little Higgs mechanism, and naturally suppressed by a two-loop factor from the SUSY breaking scale of 10 TeV. Gaugino and sfermion masses arise from standard gauge mediation, but the Higgsino obtains a tree-level mass at the SUSY breaking scale. At 1 TeV, aside from new gauge bosons and fermions similar to other little Higgs models and their superpartners, our model predi…
The theoretical status of Higgs boson and supersymmetric particle production at hadron colliders is reviewed with particular emphasis on recent results and open problems.
In this talk I discuss three-body decays of the SUSY Higgs bosons which proceed via intermediate two-body states in which one of the particles is off-mass-shell. Some of these decays will be shown to have substantial branching ratios in some range of the SUSY parameter space.
It is still an open question whether the new scalar particle discovered at the LHC with a mass of 125 GeV is the SM Higgs boson or it belongs to models of new physics with an extended Higgs sector, as the MSSM or 2HDM. The ratio of branching fractions $R$ = BR($H \to b \bar b$)/BR($H \to τ^+ τ^-$) of Higgs boson decays is a powerful tool in order to distinguish the MSSM Higgs sector from the SM or non-supersymmetric 2HDM. This ratio receives large renormalization-scheme independent radiative corrections in supersymmetric models at large $\tanβ$, which are insensitive to the SUSY mass scale and…
We have systematically investigated the production of a Higgs boson with a mass of about $125$ GeV in the decays of supersymmetric particles within the phenomenological MSSM (pMSSM). We find regions of parameter space that are consistent with all world data and that predict a sizeable rate of anomalous Higgs, di-Higgs and even tri-Higgs events at the 14 TeV LHC. All relevant SUSY production processes are investigated. We find that Higgs bosons can be produced in a large variety of SUSY processes, resulting in a large range of different detector signatures containing missing transverse momentum…
We consider the exotic decays of the SM-like Higgs state within the E6 inspired supersymmetric (SUSY) models. In these models the lightest SUSY particle (LSP) can be substantially lighter than 1 eV forming hot dark matter in the Universe. The next--to--lightest SUSY particle (NLSP) also tend to be light. We argue that the NLSP with GeV scale mass may lead to the substantial branching ratio of the nonstandard decays of the SM-like Higgs boson into NLSPs.
We consider a scenario where supersymmetry (SUSY) is broken at a relatively low scale by modular fields of extra compact spacelike dimensions. The effect of both soft and hard SUSY breaking terms on the mass of the lightest neutral Higgs boson are investigated. An important conclusion is that the lightest neutral Higgs can be considerably more massive than what is expected in the MSSM, if the overseeing theory breaks SUSY at a scale not too far above a TeV. An explicit model that implements this has been shown for illustration.
String landscape ideas and the observation of a positive vacuum energy in the current universe suggest that there could be a future transition to an exactly supersymmetric world. Atomic and molecular binding in this susy background probably require that electroweak symmetry breaking survives the transition. Among several susy higgs models that have been discussed, one stands out in this regard. Thus, the higgs structure that is revealed at the LHC could have strong consequences for the type of bulk matter that may arise in a future susy universe.
We calculate the ratio of the two branching ratios, Br(h -> bb-bar) and Br(h -> cc-bar) + Br(h -> gg), in the minimal supersymmetric standard model taking into account the SUSY-loop corrections to the Higgs sector and the hbb-bar vertex. We show that the heavy Higgs mass can be extracted from the ratio, almost independently of other SUSY parameters, in the region of tan(beta) ~< 10.
Supersymmetric models with low electroweak fine-tuning contain light higgsinos with mass not too far from m_h\simeq 125 GeV, while other sparticles can be much heavier. In the R-parity conserving MSSM, the lightest neutralino is then a higgsino-like WIMP (albeit with non-negligible gaugino components), with thermal relic density well below measured values. This leaves room for axions (or other, perhaps not as well motivated, stable particles) to function as co-dark matter particles. The local WIMP abundance is then expected to be below standard estimates, and direct and indirect detection rate…
The Higgs boson sector of the Minimal Supersymmetric Standard Model (MSSM) is investigated in a uniform way in the framework of the three most prominent soft SUSY-breaking scenarios, mSUGRA, mGMSB and mAMSB, especially concerning the Higgs searches at LEP2.
Compared with the MSSM or the NMSSM with a low λ, λ-SUSY theory with a large λaround one has been deemed as a most natural realization of NMSSM. In this work, we treat the next-to-lightest CP-even Higgs boson as the SM-like Higgs boson in λ-SUSY and study the properties of the Higgs bosons and the pair production of the SM-like Higgs boson by considering various experiment constraints. We find that naturalness plays an important role in selecting the parameter space of λ-SUSY. In the most natural region of parameter space, the triple self coupling of the SM-like Higgs boson compared with its S…
While the SUSY flavor, CP and gravitino problems seem to favor a very heavy spectrum of matter scalars, fine-tuning in the electroweak sector prefers low values of superpotential mass μ. In the limit of low μ, the two lightest neutralinos and light chargino are higgsino-like. The light charginos and neutralinos may have large production cross sections at LHC, but since they are nearly mass degenerate, there is only small energy release in three-body sparticle decays. Possible dilepton and trilepton signatures are difficult to observe after mild cuts due to the very soft p_T spectrum of the fin…
We study Higgs boson couplings in the large-$λ$ version of the Next-to-Minimal Supersymmetric Standard Model, known as $λ$-SUSY. We find that the predicted deviations from the Standard Model (SM) in these couplings are inversely correlated with the amount of fine-tuning needed to accommodate a 126 GeV Higgs. In the most natural regions of parameter space, the 126 GeV Higgs has large admixtures of both the SM-singlet and the non-SM Higgs doublet scalars, and such regions are already ruled out by the LHC. Future improvements in the Higgs coupling measurements will either discover deviations from…
In this talk we assume SO(10) boundary conditions at the GUT scale, including unification for the third generation Yukawa couplings $λ_t = λ_b = λ_τ$. We find that this assumption is only consistent with the low energy data in a narrow region of soft SUSY breaking parameter space. We discuss the consequences of this result for Higgs and SUSY searches.
We study effects of SUSY particles in the unitarity triangle analysis and the CP asymmetries in b -> s decays. We consider three different SUSY models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and MSSM with U(2) flavor symmetry, and show that the patterns and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.
Here we study and compare the sensitivity to the Higgs sector of the SUSY-seesaw models via the LFV tau decays: tau-> 3 mu, tau->K^{+}K^{-}, tau->mu eta and tau-> mu f_{0}. We emphasize that, at present, the two later channels are the most efficient ones to test indirectly the Higgs particles.
I start with a brief summary of Higgs Mechanism and supersymmetry. Then I discuss the theoretical constraints, current limits and search strategies for Higgs boson(s) at LHC - first in the SM and then in the MSSM. Finally, I discuss the analogous constraints and search strategies for the superparticles, concentrating on the minimal supergravity model. Recent advances in identifying the most promising channels for Higgs and SUSY searches are emphasized.
We study the contribution of a generic charged Higgs $(H^+)$ to the muon anomalous magnetic moment $a_μ$ with the SUSY soft breaking parameters. We find out that the deviation between the experimental data and the predicted SM value on $a_μ$ can be explained by the two-loop charged Higgs diagrams even with $m_{H^+}\sim 400 GeV$.
We calculate the order(α_s) SUSY-QCD corrections to the widths of stop and sbottom decays into Higgs bosons within the Minimal Supersymmetric Standard Model. We give the complete analytical formulae paying particular attention to the on-shell renormalization of the soft SUSY-breaking parameters. We also perform a detailed numerical analysis of both stop and sbottom decays into all Higgs bosons h^0, H^0, A^0, and H^\pm. We find that the SUSY-QCD corrections are significant, mostly negative and of the order of a few ten percent.
The implications of the LHC SUSY searches as well as the discovery of a new bosonic state compatible with the lightest Higgs boson will be discussed in the context of constrained and general MSSM scenarios. Exploring the MSSM through the Higgs sector is an alternative and complementary path to direct searches, and tight constraints on the MSSM parameter space can be obtained.
The O(alpha_s) SUSY QCD corrections to the decays of the MSSM Higgs bosons into bottom quarks and squarks can be very large for large tan beta in the on--shell renormalization scheme. We improve the calculation by a careful choice of the tree-level Higgs boson couplings in terms of running parameters of quarks and squarks.
We present the state-of-the-art of the effective field theory computation of the MSSM Higgs mass, improving the existing ones by including extra threshold corrections. We show that, with this approach, the theoretical uncertainty is within 1 GeV in most of the relevant parameter space. We confirm the smaller value of the Higgs mass found in the EFT computations, which implies a slightly heavier SUSY scale. We study the large tan(β) region, finding that sbottom thresholds might relax the upper bound on the scale of SUSY. We present SusyHD, a fast computer code that computes the Higgs mass and i…
I present applications of a master formula for next-to-next-to-leading order soft and virtual QCD corrections to various electroweak, Higgs, and supersymmetric processes. They include Drell-Yan and charged Higgs production, single-top production in flavor-changing neutral-current processes, and squark and gluino production.
The associated production of a Higgs boson with a b quark is a discovery mode for an MSSM Higgs boson at large tan beta. We compute the SUSY QCD corrections from gluino and squark loops to this process and combine them with the order alpha_s^2 NLO QCD corrections to obtain reliable predictions for the rate. Finally, we compare our results with an effective Lagrangian approximation which includes only the low energy corrections from squark and gluino loops to the b- bbar- Higgs vertices.
We consider a plausible scenario in the Minimal Supersymmetric Standard Model (MSSM) where all the genuine supersymmetric (SUSY) particles are heavier than the electroweak scale. In this situation, indirect searches via their radiative corrections to low energy observables are complementary to direct searches, and they can be crucial if the SUSY masses are at the TeV energy range. We summarize the most relevant heavy SUSY radiative effects in Higgs boson physics and emphasize those that manifest a non-decoupling behaviour. We focus, in particular, on the SUSY-QCD non-decoupling effects in ferm…
We compute the mass of the Higgs particle in a scheme in which SUSY is broken at a large scale M_{SS} well above the electroweak scale M_{EW}. Below M_{SS} one assumes one is just left with the SM with a fine-tuned Higgs potential. Under standard unification assumptions one can compute the mass of the Higgs particle as a function of the SUSY breaking scale M_{SS}. For M_{SS} > 10^{10} GeV one obtains m_H=126 \pm 3 GeV, consistent with CMS and ATLAS results. For lower values of M_{SS} the values of the Higgs mass tend to those of a fine-tuned MSSM with m_H < 130 GeV. These results support the i…
The processes e+e- -> t tbar/b bbar + Higgs allow to measure the Yukawa couplings between Higgs bosons and heavy quarks in supersymmetric theories. The complete set of next-to-leading order SUSY-QCD corrections to the cross sections of these processes have been determined in the minimal supersymmetric extension of the Standard Model. They turn out to be O(10-20%) and thus important for future linear e+e- colliders.
We study the Higgs potential of the next-to-minimal renormalizable SUSY SO(10) GUT with 120 Higgs representation on top of the "standard" minimal model Higgs sector spanning over 10, 126bar+126 and 210. All the GUT-scale Higgs sector mass matrices for the 592 Higgs states of the model are written down in detail with all the conventions fully specified. The consistency of the results is checked by the decoupling of 120 and independently by the analysis of the relevant Goldstone modes. The matching of the Yukawa sector sum-rules driving the matter fermion masses and mixing at the level of the ef…
We compute Gamma(H+ -> t \bar{b}) at one-loop in the MSSM and show how future data at the Tevatron and/or at the LHC could be used to unravel the potential SUSY nature of the charged Higgs.
We analyze the next-to-leading order SUSY-QCD corrections to the production of Higgs particles at hadron colliders in supersymmetric extensions of the Standard Model. Besides the standard QCD corrections due to gluon exchange and emission, genuine supersymmetric corrections due to the virtual exchange of squarks and gluinos are present. At both the Tevatron and the LHC, these corrections are found to be small in the Higgs-strahlung, Drell-Yan-like Higgs pair production and vector boson fusion processes.
Recent evidence from the LHC for the Higgs boson with mass between 142 GeV < m_h < 147GeV points to PeV-scale Split Supersymmetry. This article explores the consequences of a Higgs mass in this range and possible discovery modes for Split Susy. Moderate lifetime gluinos, with decay lengths in the 25 microns to 10 years range, are its imminent smoking gun signature. The 7 TeV LHC will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production. Moreover, the dark matter abundance may be obtained from annihilation through an s-channel Higgs resonan…
There are two different types of perturbative unification in SUSY GUTs. Perturbative gauge unification is necessary for the extremely successful prediction of $\sin^2θ_w$. ``Perturbative validity'' requires that {\it all} couplings (not just the gauge couplings) remain small; this assumption is essential to the proof that any SUSY GUT must have a light Higgs with a mass below 140 GeV. It is pointed out here that if the latter bound is violated (so that there need be no light Higgs bosons), then it is plausible that the successful prediction of $\sin^2θ_w$ will {\it not} be significantly altere…
We assume that the scale of the soft supersymmetry breaking masses, m_SUSY, sliding at tree level, is fixed by the minimization of the potential, but without a significant contribution of the cosmological term. Under these assumptions the electroweak breaking scale gets related to m_SUSY by a loop factor. Applied to specific models of supersymmetry breaking, this mechanism naturally gives sparticles slightly above all present accelerator bounds.
If Supersymmetry (SUSY) has a compressed spectrum the current limits from the LHC can be drastically reduced. We take possible `worst case' scenarios where combinations of the stop, squark and gluino masses are degenerate with the mass of the lightest SUSY particle. To accurately derive limits in the model, care must be taken when describing QCD radiation and we examine this in detail. Lower mass bounds are then produced by considering all the 7 TeV hadronic SUSY and monojet searches. The evolution of the limits as the mass splitting is varied is also presented.
We show that an enhanced two-photon signal of the Higgs boson, h, observed with 125 GeV mass by the ATLAS and CMS collaborations, can be obtained if it is identified principally with the neutral $H_u^0$ of the two Higgs doublets of minimal Supersymmetry. We focus on sparticles and the pseudoscalar Higgs $A$ at the TeV scale. The off-diagonal element of the (Hu0,Hd0) mass matrix in the flavor basis must be suppressed, and this requires both a large Higgsino mass parameter, mu \sim TeV, and large tan beta. A MSSM sum rule is derived that relates gamma gamma and bb rates, and the gamma gamma enha…
In the context of the Minimal Supersymmetric extension of the Standard Model, we discuss the impact of the decays of the neutral Higgs bosons into supersymmetric particles, charginos/neutralinos and sfermions. We show that these decay modes could be dominant, when they are kinematically accessible, thus strongly suppressing the branching ratios for the decay channels which are used to detect the Higgs bosons at hadron colliders. These SUSY decay modes should therefore not be overlooked in the search for the Higgs particles at the LHC.
I briefly review the physics of the Higgs sector in the Standard Model (SM) and its supersymmetric extension, in particular the MSSM, and discuss the prospects for discovering the Higgs particles at the Large Hadron Collider. Some emphasis will be put on the theoretical developments which occurred in the last few years.
An overview of hints for new physics outside the Standard Model and the status of sparticle and Higgs searches is given. The present limits on Higgs bosons of about 90 GeV as well as the $\bsg$ rate and cosmological constraints severely restrict the available parameter space of the MSSM.
We show that the gauge mediation models with vector-like matters can explain the Higgs boson mass of 126 GeV without large soft scalar masses nor a large left-right mixing of the stops. The scenario has interesting features: the existence of the light non-colored SUSY particles accessible at the LHC and ILC, the explanation of the muon g-2 and the possibility of the enhanced di-photon decay rate of the Higgs boson.
In the $SO(5) \times U(1)$ gauge-Higgs unification in the Randall-Sundrum (RS) warped space the Higgs boson naturally becomes stable. The model is consistent with the current collider signatures only for a large warp factor $z_L > 10^{15}$ of the RS space. In order for stable Higgs bosons to explain the dark matter of the Universe the Higgs boson must have a mass $m_h = 70 \sim 75$ GeV, which can be obtained in the non-SUSY model with $z_L \sim 10^5$. We show that this discrepancy is resolved in supersymmetric gauge-Higgs unification where a stop mass is about $300 \sim 320 $GeV and gauginos i…
We study the stability of the effective higgs potential in the split supersymmetry and Little Higgs models. In particular, we study the effects of higher dimensional operators in the effective potential on the higgs mass predictions. We find that the size and sign of the higher dimensional operators can significantly change the higgs mass required to maintain vacuum stability in Split Susy models. In the Little Higgs models the effects of higher dimensional operators can be large because of a relatively lower cut-off scale. Working with a specific model we find that a contribution from the hig…
We demonstrate that soft SUSY breaking introduced via replacement of the couplings of a rigid theory by spurion superfields has far reaching consequences. Substituting these modified couplings into renormalization constants, RG equations, solutions to these equations, fixed points, finiteness conditions, etc., one can get corresponding relations for the soft terms by a simple Taylor expansion over the Grassmannian variables. This way one can get new solutions of the RG equations. Some examples including the MSSM, SUSY GUTs and the N=2 Seiberg-Witten model are given.
Properties of Dirac neutralinos and the corresponding EW scalar gauge bosons, as predicted by the N=1/N=2 hybrid supersymmetric model, and prospects for their discovery at colliders are discussed.
Recent theoretical developments concerning Higgs production at the Large Hadron Collider are reviewed, both in the Standard Model and in the MSSM. Emphasis is put on the inclusive and exclusive cross sections for gluon fusion, as well as on the associated production with bottom quarks.
The upper bound on the mass of the lightest Higgs boson is provided in the supersymmetric standard model with multi-Higgs doublets, up to two-loop order. Relatively large corrections are expected from the experimentally unconstrained extra Yukawa couplings. We calculate it including the two-loop leading-log contributions as a function of the scale $Λ$, below which the theory remains perturbative. Even for $Λ=10^{4}$ GeV, we obtain the upper bound of 140 GeV, which is heavier than that of the MSSM by 10 GeV.
I discuss the decay modes of the neutral and charged Higgs bosons in the minimal supersymmetric extension of the Standard Model. Special emphasis will be put on the the QCD corrections to the hadronic decay modes, the below threshold -three body- decays and the decays into supersymmetric particles, charginos, neutralinos and sfermions. A Fortran code calculating the various Higgs decay branching ratios is then briefly presented. [Talk given at the Ringberg Workshop The Higgs Puzzle, Ringberg Castle, Tegernsee, Germany, December 8-13 1996; to appear in the proceedings.]
In this talk, I discuss some aspects of Higgs searches at future colliders, particularly comparing and contrasting the capabilities of LHC and Next Linear Collider (NLC), including the aspects of Higgs searches in supersymmetric theories. After this, I will discuss how the search and study of sparticles other than the Higgs can give information about the parameters of the Minimal Supersymmetric Standard Model (MSSM).
We study the Higgs boson mass and the spectrum of supersymmetric (SUSY) particles in the well-motivated particle physics model derived from a ten-dimensional supersymmetric Yang-Mills theory compactified on three factorizable tori with magnetic fluxes. This model was proposed in a previous work, where the flavor structures of the standard model including the realistic Yukawa hierarchies are obtained from non-hierarchical input parameters on the magnetized background. Assuming moduli- and anomaly-mediated contributions dominate the soft SUSY breaking terms, we study the precise SUSY spectra and…
Though the mass of Higgs particle is the parameter determined by the experiment in the standard model (SM), SUSY models have rather predictive power for the lightest Higgs mass, and its upper bound in some SUSY models are close to the observable region in LEP2. The upper bound of the lightest Higgs mass is analysed systematically on the basis of the $CP$ violation in the minimal and the next minimal supersymmetric standard model (MSSM and NMSSM). In the explicit $CP$ violation case, the mass bound is large around $130 \sim 160$ GeV in both models. In the spontaneous $CP$ violation case induced…
We analyze the contribution of the SUSY particles to the coupling of the lightest Higgs boson to two photons in supersymmetric theories. We discuss to what extent these contributions can be large enough to allow for a discrimination between the lightest SUSY and the standard Higgs particles in the decoupling limit where all other Higgs bosons are very heavy and no supersymmetric particle has been discovered at future colliders. We find that only chargino and top squark loops can generate a sizeable difference between the standard and the SUSY Higgs-photon couplings. For masses above 250 GeV, t…
We study the decays of the SM-like Higgs state within the E6 inspired supersymmetric (SUSY) models with exact custodial symmetry that forbids tree-level flavor-changing transitions and the most dangerous baryon and lepton number violating operators. In these models there are two states which are absolutely stable and can contribute to the dark matter density. One of them is the lightest SUSY particle (LSP) which is expected to be lighter than 1 eV forming hot dark matter in the Universe. The presence of another stable neutral state allows to account for the observed cold dark matter density. I…
The recent discovery of a SM-like Higgs boson at the LHC, with a mass around 125-126 GeV, together with the absence of results in the direct searches for supersymmetry, is pushing the SUSY scale ($m_\text{SUSY}$) into the multi-TeV range. This discouraging situation from a low-energy SUSY point of view has its counterpart in indirect SUSY observables which present a non-decoupling behavior with $m_\text{SUSY}$. This is the case of the one-loop lepton flavor violating Higgs decay rates induced by SUSY, which are shown here to remain constant as $m_\text{SUSY}$ grows, for large $m_\text{SUSY} >$…
