WorldWideScience

Sample records for higgs phenomenology predicted

  1. Phenomenology of Higgs particles

    International Nuclear Information System (INIS)

    Jarlskog, C.; Stockholm Univ.

    1985-01-01

    These lecture notes are organized as follows: 1. Introduction, 2. Interactions and decay modes of the Standard Higgs phisub(O), 3. Nonstandard Higgs multiplets, 4. Upper limits on the Higgs mass, 5. Lower limits on the Higgs mass, 6. Production mechanisms for the Standard Higgs, 7. Outlook. (orig.)

  2. Phenomenologies of Higgs messenger models

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Sibo; Yu Yao; Wu Xinggang [Department of Physics, Chongqing University, Chongqing 401331 (China)

    2011-08-11

    In this Letter, we investigate the phenomenologies of models where the Higgs sector plays the role of messengers in gauge mediation. The minimal Higgs sector and its extension are considered respectively. We find that there exist viable models when an appropriate parity is imposed. Phenomenological features in these kind of models include three sum rules for scalar masses, light gluino as well as one-loop {mu} and two-loop B{mu} terms.

  3. Phenomenology of the Higgs boson

    International Nuclear Information System (INIS)

    Ali, A.

    1981-09-01

    The phenomenology of the standard Weinberg-Salam Higgs boson is reviewed with particular emphasis on production mechanisms in high energy e + e - and hadron-hadron collisions. The production processes relevant for the ISABELLE and TEVATRON energies are discussed and their backgrounds estimated. It is argued that the toponium production and radiative decay provides the most hopeful reaction to detect a Higgs in both the e + e - and the hadron-hadron machines. (orig.)

  4. Light Higgs bosons in phenomenological NMSSM

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, F. [CERN, Geneva (Switzerland); Clermont Univ., CNRS/IN2P3, LPC, Clermont-Ferrand (France); Rathsman, J. [Uppsala Univ. (Sweden). High-Energy Physics; Lund Univ. (Sweden). Theoretical High Energy Physics; Staal, O. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zeune, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Goettingen Univ. (Germany). II. Physikalisches Inst.

    2010-12-15

    We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constraints from both high-energy collider and flavour physics, the Higgs boson masses and couplings are studied in viable parts of parameter space. The LHC phenomenology of the light Higgs scenario for neutral and charged Higgs boson searches is discussed. (orig.)

  5. Light Higgs bosons in phenomenological NMSSM

    International Nuclear Information System (INIS)

    Mahmoudi, F.; Rathsman, J.; Zeune, L.; Goettingen Univ.

    2010-12-01

    We consider scenarios in the next-to-minimal supersymmetric model (NMSSM) where the CP-odd and charged Higgs bosons are very light. As we demonstrate, these can be obtained as simple deformations of existing phenomenological MSSM benchmarks scenarios with parameters defined at the weak scale. This offers a direct and meaningful comparison to the MSSM case. Applying a wide set of up-to-date constraints from both high-energy collider and flavour physics, the Higgs boson masses and couplings are studied in viable parts of parameter space. The LHC phenomenology of the light Higgs scenario for neutral and charged Higgs boson searches is discussed. (orig.)

  6. Phenomenological viability of orbifold models with three Higgs families

    International Nuclear Information System (INIS)

    Escudero, Nicolas; Munoz, Carlos; Teixeira, Ana M.

    2006-01-01

    We discuss the phenomenological viability of string multi-Higgs doublet models, namely a scenario of heterotic Z 3 orbifolds with two Wilson lines, which naturally predicts three supersymmetric families of matter and Higgs fields. We study the orbifold parameter space, and discuss the compatibility of the predicted Yukawa couplings with current experimental data. We address the implications of tree-level flavour changing neutral processes in constraining the Higgs sector of the model, finding that viable scenarios can be obtained for a reasonably light Higgs spectrum. We also take into account the tree-level contributions to indirect CP violation, showing that the experimental value of ε K can be accommodated in the present framework

  7. Interplay of Higgs phenomenology and new physics in supersymmetric theories

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shruti

    2017-10-15

    Supersymmetric (SUSY) theories such as the Minimal Supersymmetric Standard Model (MSSM) predict a new particle spectrum, including an extended Higgs sector, in order to address fundamental questions that remain unanswered with the results obtained at the Large Hadron Collider (LHC) so far. Despite an extensive programme to search for additional Higgs bosons at the LHC, no new Higgs-like particles have been observed beyond the discovered signal at 125 GeV. Such searches have not taken into account CP-violating effects in the Higgs sector, which are well-motivated in the light of the perceived baryon asymmetry in the universe, and which can induce significant deviations in the phenomenology of the Higgs bosons. The search for additional Higgs bosons should therefore account for the possibility that they may not necessarily be CP-eigenstates. In the most general case where the MSSM parameters can be complex, the three neutral Higgs bosons of the theory are the loop-corrected mass eigenstates {h_1,h_2,h_3}, which are admixtures of the tree-level CP-even and CP-odd Higgs states. This thesis focusses on the effects of complex parameters on the production cross sections of these Higgs bosons and the interference occurring between nearly mass-degenerate Higgs states. In the first part of this thesis, we discuss higher-order corrections in the Higgs sector which give rise to CP-violating mixing between the tree-level mass eigenstates, and present a computation of inclusive cross sections for the production of the CP-admixed Higgs bosons through gluon fusion and bottom-quark annihilation. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for the general case of arbitrary complex parameters, supplemented by various higher-order corrections. The cross sections for the bottom-quark annihilation process are treated with a simple re-weighting procedure. In the next part, we describe the implementation of our

  8. Interplay of Higgs phenomenology and new physics in supersymmetric theories

    International Nuclear Information System (INIS)

    Patel, Shruti

    2017-10-01

    Supersymmetric (SUSY) theories such as the Minimal Supersymmetric Standard Model (MSSM) predict a new particle spectrum, including an extended Higgs sector, in order to address fundamental questions that remain unanswered with the results obtained at the Large Hadron Collider (LHC) so far. Despite an extensive programme to search for additional Higgs bosons at the LHC, no new Higgs-like particles have been observed beyond the discovered signal at 125 GeV. Such searches have not taken into account CP-violating effects in the Higgs sector, which are well-motivated in the light of the perceived baryon asymmetry in the universe, and which can induce significant deviations in the phenomenology of the Higgs bosons. The search for additional Higgs bosons should therefore account for the possibility that they may not necessarily be CP-eigenstates. In the most general case where the MSSM parameters can be complex, the three neutral Higgs bosons of the theory are the loop-corrected mass eigenstates {h 1 ,h 2 ,h 3 }, which are admixtures of the tree-level CP-even and CP-odd Higgs states. This thesis focusses on the effects of complex parameters on the production cross sections of these Higgs bosons and the interference occurring between nearly mass-degenerate Higgs states. In the first part of this thesis, we discuss higher-order corrections in the Higgs sector which give rise to CP-violating mixing between the tree-level mass eigenstates, and present a computation of inclusive cross sections for the production of the CP-admixed Higgs bosons through gluon fusion and bottom-quark annihilation. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for the general case of arbitrary complex parameters, supplemented by various higher-order corrections. The cross sections for the bottom-quark annihilation process are treated with a simple re-weighting procedure. In the next part, we describe the implementation of our

  9. Higgs boson phenomenology at the LHC

    International Nuclear Information System (INIS)

    Kirchner, Sebastian

    2016-01-01

    The outstanding performance of the Large Hadron Collider (LHC) led to the discovery of the Higgs boson in 2012. The paramount endeavour after this discovery is the examination of the Higgs-boson properties, amongst others the determination of its CP quantum number and total decay width. The experimental analysis of both properties requires precise theoretical input within the Standard Model of particle physics. Theoretical methods and predictions at next-to-leading-order (NLO) in perturbative Quantum Chromodynamics (QCD), addressing the CP nature and decay width of the Higgs boson, are presented in this thesis. The thesis is split in two parts: The first part addresses the Caola-Melnikov method, which is utilised to constrain the Higgs width that is experimentally not directly measurable. The method relies on cross section measurements on and far off the Higgs boson peak. Two-loop corrections via a heavy top quark to the gluon-gluon initialised Z boson pair-production are examined as an expansion about the heavy-top limit combined with a conformal mapping and Pade approximants. The impact of the full NLO QCD corrections to the signal and background cross sections, relevant for bounding the Higgs width, is investigated. The second part of this thesis examines how precisely the CP nature of the Higgs boson can be unravelled in its decay to tau lepton pairs. All subsequent major charged-prong decays of the tau leptons are included.The impact parameter method is utilised and allows to extract the CP-mixing angle of the Higgs boson from the distribution of a signed angle. NLO QCD predictions for the signal process as well as the Drell-Yan background, including a Monte Carlo simulation of measurement uncertainties, are computed. Energy and angular correlations of the charged prongs are analysed and used to suppress the Drell-Yan background contribution. In a second step, the sensitivity to the CP-mixing angle is increased by combining the impact parameter method with the

  10. Phenomenology of a nonstandard Higgs boson in WLWL scattering

    International Nuclear Information System (INIS)

    Koulovassilopoulos, V.; Chivukula, R.S.

    1994-01-01

    In this paper we consider the phenomenology of a nonstandard Higgs boson in longitudinal gauge boson scattering. First, we present a composite Higgs model [based on an SU(4)/Sp(4) chiral-symmetry breaking pattern] in which there is a nonstandard Higgs boson. Then we explore, in a model-independent way, the phenomenology of such a nonstandard Higgs boson by calculating the leading one-loop logarithmic corrections to longitudinal gauge boson scattering. This calculation is done using the equivalence theorem and the Higgs boson is treated as a scalar-isoscalar resonance coupled to the Goldstone bosons of the SU(2) L xSu(2) R /SU(2) V chiral symmetry breaking. We show that the most important deviation from the one-Higgs-doublet standard model is parametrized by one unknown coefficient which is related to the Higgs-boson width. The implications for future hadron colliders are discussed

  11. Higgs-radion phenomenology in stabilized RS models

    Directory of Open Access Journals (Sweden)

    Boos Eduard

    2016-01-01

    Full Text Available An important general prediction of stabilized brane world models is the existence of a bulk scalar radion field, whose lowest Kaluza-Klein (KK mode is the scalar particle called the radion. This field comes from the fluctuations of the metric in the extra dimension and the radion mass can be smaller than that of all the massive KK modes of the other particles propagating in the multidimensional bulk. Due to its origin, the radion and its KK tower couple to the trace of the energy-momentum tensor of the Standard Model. These fields have the same quantum numbers as the neutral Higgs field and can mix with the latter, if they are coupled. We present a short review of some aspects of Higgs-radion phenomenology in stabilized brane-world models. In particular, we discuss the possibility of explaining the 750 GeV excess by the production of a radion-dominated state.

  12. Phenomenological comparison of models with extended Higgs sectors

    International Nuclear Information System (INIS)

    Muehlleitner, Margarete

    2017-01-01

    Beyond the Standard Model (SM) extensions usually include extended Higgs sectors. Models with singlet or doublet fields are the simplest ones that are compatible with the ρ parameter constraint. The discovery of new non-SM Higgs bosons and the identification of the underlying model requires dedicated Higgs properties analyses. In this paper, we compare several Higgs sectors featuring 3 CP-even neutral Higgs bosons that are also motivated by their simplicity and their capability to solve some of the flaws of the SM. They are: the SM extended by a complex singlet field (C x SM), the singlet extension of the 2-Higgs-Doublet Model (N2HDM), and the Next-to-Minimal Supersymmetric SM extension (NMSSM). In addition, we analyse the CP-violating 2-Higgs-Doublet Model (C2HDM), which provides 3 neutral Higgs bosons with a pseudoscalar admixture. This allows us to compare the effects of singlet and pseudoscalar admixtures. Through dedicated scans of the allowed parameter space of the models, we analyse the phenomenologically viable scenarios from the view point of the SM-like Higgs boson and of the signal rates of the non-SM-like Higgs bosons to be found. In particular, we analyse the effect of singlet/pseudoscalar admixture, and the potential to differentiate these models in the near future. This is supported by a study of couplings sums of the Higgs bosons to massive gauge bosons and to fermions, where we identify features that allow us to distinguish the models, in particular when only part of the Higgs spectrum is discovered. Our results can be taken as guidelines for future LHC data analyses, by the ATLAS and CMS experiments, to identify specific benchmark points aimed at revealing the underlying model.

  13. Phenomenological comparison of models with extended Higgs sectors

    Energy Technology Data Exchange (ETDEWEB)

    Muehlleitner, Margarete [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Theoretical Physics; Sampaio, Marco O.P. [Aveiro Univ. e CIDMA (Portugal). Dept. de Fisica; Santos, Rui [Instituto Politecnico de Lisboa (Portugal). ISEL - Instituto Superior de Engenharia de Lisboa; Lisboa Univ. (Portugal). Centro de Fisica Teorica e Computacional; Univ. do Minho, Braga (Portugal). LIP, Dept. de Fisica; Wittbrodt, Jonas [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Theoretical Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2017-03-22

    Beyond the Standard Model (SM) extensions usually include extended Higgs sectors. Models with singlet or doublet fields are the simplest ones that are compatible with the ρ parameter constraint. The discovery of new non-SM Higgs bosons and the identification of the underlying model requires dedicated Higgs properties analyses. In this paper, we compare several Higgs sectors featuring 3 CP-even neutral Higgs bosons that are also motivated by their simplicity and their capability to solve some of the flaws of the SM. They are: the SM extended by a complex singlet field (C x SM), the singlet extension of the 2-Higgs-Doublet Model (N2HDM), and the Next-to-Minimal Supersymmetric SM extension (NMSSM). In addition, we analyse the CP-violating 2-Higgs-Doublet Model (C2HDM), which provides 3 neutral Higgs bosons with a pseudoscalar admixture. This allows us to compare the effects of singlet and pseudoscalar admixtures. Through dedicated scans of the allowed parameter space of the models, we analyse the phenomenologically viable scenarios from the view point of the SM-like Higgs boson and of the signal rates of the non-SM-like Higgs bosons to be found. In particular, we analyse the effect of singlet/pseudoscalar admixture, and the potential to differentiate these models in the near future. This is supported by a study of couplings sums of the Higgs bosons to massive gauge bosons and to fermions, where we identify features that allow us to distinguish the models, in particular when only part of the Higgs spectrum is discovered. Our results can be taken as guidelines for future LHC data analyses, by the ATLAS and CMS experiments, to identify specific benchmark points aimed at revealing the underlying model.

  14. Higgs phenomenology in the minimal S U (3 )L×U (1 )X model

    Science.gov (United States)

    Okada, Hiroshi; Okada, Nobuchika; Orikasa, Yuta; Yagyu, Kei

    2016-07-01

    We investigate the phenomenology of a model based on the S U (3 )c×S U (3 )L×U (1 )X gauge theory, the so-called 331 model. In particular, we focus on the Higgs sector of the model which is composed of three S U (3 )L triplet Higgs fields and is the minimal form for realizing a phenomenologically acceptable scenario. After the spontaneous symmetry breaking S U (3 )L×U (1 )X→S U (2 )L×U (1 )Y , our Higgs sector effectively becomes that with two S U (2 )L doublet scalar fields, in which the first- and the second-generation quarks couple to a different Higgs doublet from that which couples to the third-generation quarks. This structure causes the flavor-changing neutral current mediated by Higgs bosons at the tree level. By taking an alignment limit of the mass matrix for the C P -even Higgs bosons, which is naturally realized in the case with the breaking scale of S U (3 )L×U (1 )X much larger than that of S U (2 )L×U (1 )Y, we can avoid current constraints from flavor experiments such as the B0-B¯ 0 mixing even for the Higgs bosons masses that are O (100 ) GeV . In this allowed parameter space, we clarify that a characteristic deviation in quark Yukawa couplings of the Standard Model-like Higgs boson is predicted, which has a different pattern from that seen in two Higgs doublet models with a softly broken Z2 symmetry. We also find that the flavor-violating decay modes of the extra Higgs boson, e.g., H /A →t c and H±→t s , can be dominant, and they yield the important signature to distinguish our model from the two Higgs doublet models.

  15. Theory and Phenomenology of the Elementary Goldstone Higgs

    DEFF Research Database (Denmark)

    Gertov, Helene; Meroni, Aurora; Molinaro, Emiliano

    2015-01-01

    We show, via a careful analytical and numerical analysis, that a pseudo Goldstone nature of the Higgs is naturally embodied by an elementary realization that also serves as ultraviolet completion. Renormalizability married to perturbation theory allows to precisely determine the quantum corrections...... of the theory while permitting to explore the underlying parameter space. By characterising the available parameter space of the extended Higgs sector we discover that the preferred electroweak alignment angle is centred around $\\theta \\simeq 0.02$, corresponding to the Higgs chiral symmetry breaking scale $ f...... \\simeq 14~$TeV. The latter is almost 60 times higher than the Standard Model electroweak scale. However, due to the perturbative nature of the theory, the spectrum of the enlarged Higgs sector remains in the few TeV energy range. We also analyse precision constraints and the relevant phenomenological...

  16. LHC phenomenology of composite 2-Higgs doublet models

    Energy Technology Data Exchange (ETDEWEB)

    De Curtis, Stefania [University of Florence, Department of Physics and Astronomy, Sesto Fiorentino (Italy); INFN, Sezione di Firenze (Italy); Moretti, Stefano; Yagyu, Kei; Yildirim, Emine [University of Southampton, School of Physics and Astronomy, Southampton (United Kingdom)

    2017-08-15

    We investigate the phenomenology of Composite 2-Higgs doublet models (C2HDMs) of various Yukawa types based on the global symmetry breaking SO(6) → SO(4) x SO(2). The kinetic part and the Yukawa Lagrangian are constructed in terms of the pseudo Nambu-Goldstone Boson (pNGB) matrix and a 6-plet of fermions under SO(6). The scalar potential is assumed to be the same as that of the Elementary 2-Higgs doublet model (E2HDM) with a softly broken discrete Z{sub 2} symmetry. We then discuss the phenomenological differences between the E2HDM and C2HDM by focusing on the deviations from standard model (SM) couplings of the discovered Higgs state (h) as well as on the production cross sections and branching ratios (BRs) at the large Hadron collider (LHC) of extra Higgs bosons. We find that, even if the same deviation in the hVV (V = W,Z) coupling is assumed in the two scenarios, there appear significant differences between the E2HDM and C2HDM from the structure of the Yukawa couplings, so that production and decay features of extra Higgs bosons can be used to distinguish between the two scenarios. (orig.)

  17. Higgs Phenomenology of Minimal Universal Extra Dimensions

    Directory of Open Access Journals (Sweden)

    Kakizaki Mitsuru

    2012-06-01

    Full Text Available The minimal model of Universal Extra Dimensions (MUED is briefly reviewed. We explain how the cross-sections for Higgs production via gluon fusion and decay into photons are modified, relative the the Standard Model (SM values, by KK particles running in loops, leading to an enhancement of the gg → h → γγ and gg → h → W+W− cross-sections. ATLAS and CMS searches for the SM Higgs in these channels are reinterpreted in the context of MUED and used to place new limits on the MUED parameter space. Only a small region of between 1 and 3 GeV around mh = 125 GeV for 500 GeV < R−1 < 1600 GeV remains open at the 95 % confidence level.

  18. Phenomenology of a leptonic goldstino and invisible Higgs boson decays

    CERN Document Server

    Antoniadis, Ignatios; Zwirner, Fabio; Antoniadis, Ignatios; Tuckmantel, Marc; Zwirner, Fabio

    2005-01-01

    Non-linearly realized supersymmetry, combined with the Standard Model field content and SU(3)XSU(2)XU(1) gauge invariance, permits local dimension-six operators involving a goldstino, a lepton doublet and a Higgs doublet. These interactions preserve total lepton number if the left-handed goldstino transforms as an antilepton. We discuss the resulting phenomenology, in the simple limit where the new couplings involve only one lepton family, thus conserving also lepton flavour. Both the Z boson and the Higgs boson can decay into a neutrino and a goldstino: the present limits from the invisible Z width and from other observables leave room for the striking possibility of a Higgs boson decaying dominantly, or at least with a sizable branching ratio, via such an invisible mode. We finally comment on the perspectives at hadron and lepton colliders, and on possible extensions of our analysis.

  19. Higgs couplings and phenomenology in a warped extra dimension

    International Nuclear Information System (INIS)

    Malm, Raoul; Neubert, Matthias; Schmell, Christoph

    2015-01-01

    We present a comprehensive description of the Higgs-boson couplings to Standard Model fermions and bosons in Randall-Sundrum (RS) models with a Higgs sector localized on or near the infra-red brane. The analytic results for all relevant Higgs couplings including the loop-induced couplings to gluons and photons are summarized for both the minimal and the custodial RS model. The RS predictions for all relevant Higgs decays are compared with current LHC data, which already exclude significant portions of the parameter space. We show that the latest measurements are sensitive to KK gluon masses up to 22.7 TeV×(y ⋆ /3) at 95% confidence level for anarchic 5D Yukawa couplings bounded from above by |(Y f ) ij |≤y ⋆ . We also derive the sensitivity levels attainable in the high-luminosity run of the LHC and at a future linear collider.

  20. Singlet Higgs phenomenology and the electroweak phase transition

    International Nuclear Information System (INIS)

    Profumo, Stefano; Ramsey-Musolf, Michael J.; Shaughnessy, Gabe

    2007-01-01

    We study the phenomenology of gauge singlet extensions of the Standard Model scalar sector and their implications for the electroweak phase transition. We determine the conditions on the scalar potential parameters that lead to a strong first order phase transition as needed to produce the observed baryon asymmetry of the universe. We analyze the constraints on the potential parameters derived from Higgs boson searches at LEP and electroweak precision observables. For models that satisfy these constraints and that produce a strong first order phase transition, we discuss the prospective signatures in future Higgs studies at the Large Hadron Collider and a Linear Collider. We argue that such studies will provide powerful probes of phase transition dynamics in models with an extended scalar sector

  1. Phenomenology of SU(5 low-energy realizations: The diphoton excess and Higgs flavor violation

    Directory of Open Access Journals (Sweden)

    Andrea Di Iura

    2016-10-01

    Full Text Available We discuss different SU(5 low-energy realizations and illustrate their use with the diphoton excess and Higgs flavor violation, which require new physics at the TeV scale. In particular, we study two scenarios for a 750 GeV resonance: in the first one the resonance belongs to the adjoint of SU(5, being either an SU(2L singlet or a triplet, while in the second case the signal is due to the CP-even and CP-odd states of a new SU(2L Higgs doublet belonging to a 45H or a 70H representations, giving rise to a two-Higgs doublet model at low energies. We study the fine-tuning needed for the desired members of the multiplets to be light enough, while having the rest at the GUT scale. In these scenarios, the production and decay into photons of the new resonance are mediated by the leptoquarks (LQ present in these large SU(5 representations. We analyze the phenomenology of such scenarios, focusing on the most relevant predictions that can help to disentangle the different models, like decays into gauge bosons, Standard Model (SM fermions and LQs pair production. In the case of the 45H (the Georgi–Jarlskog model, we also study the possibility to have Higgs flavor violation. We find that Bs mixing limits (in addition to τ→μγ always imply that Br(h→τμ,bs≲10−5.

  2. Light dark matter in NMSSM and implication on Higgs phenomenology

    International Nuclear Information System (INIS)

    Cao Junjie; Hikasa, Ken-ichi; Wang Wenyu; Yang Jinmin

    2011-01-01

    For the experimental search of neutralino dark matter, it is important to know its allowed mass and scattering cross section with the nucleon. In order to figure out how light a neutralino dark matter can be predicted in low energy supersymmetry, we scan over the parameter space of the NMSSM (next-to-minimal supersymmetric model), assuming all the relevant soft mass parameters to be below TeV scale. We find that in the parameter space allowed by current experiments the neutralino dark matter can be as light as a few GeV and its scattering rate off the nucleon can reach the sensitivity of XENON100 and CoGeNT. As a result, a sizable parameter space is excluded by the current XENON100 and CoGeNT data (the plausible CoGeNT dark matter signal can also be explained). The future 6000 kg-days exposure of XENON100 will further explore (but cannot completely cover) the remained parameter space. Moreover, we find that in such a light dark matter scenario a light CP-even or CP-odd Higgs boson must be present to satisfy the measured dark matter relic density. Consequently, the SM-like Higgs boson h SM may decay predominantly into a pair of light Higgs bosons or a pair of neutralinos so that the conventional decays like h SM →γγ is much suppressed.

  3. Phenomenology of the Higgs at the hadron colliders: from the standard model to supersymmetry

    International Nuclear Information System (INIS)

    Baglio, J.

    2011-10-01

    This thesis has been conducted in the context of one of the utmost important searches at current hadron colliders, that is the search for the Higgs boson, the remnant of the electroweak symmetry breaking. We wish to study the phenomenology of the Higgs boson in both the Standard Model (SM) framework and its minimal Supersymmetric extension (MSSM). After a review of the Standard Model in a first part and of the key reasons and ingredients for the supersymmetry in general and the MSSM in particular in a third part, we will present the calculation of the inclusive production cross sections of the Higgs boson in the main channels at the two current hadron colliders that are the Fermilab Tevatron collider and the CERN Large Hadron Collider (LHC), starting by the SM case in the second part and presenting the MSSM results, where we have 5 Higgs bosons and focusing on the two main production channels that are the gluon gluon fusion and the bottom quarks fusion, in the fourth part. The main output of this calculation is the extensive study of the various theoretical uncertainties that affect the predictions: the scale uncertainties which probe our ignorance of the higher-order terms in a fixed order perturbative calculation, the parton distribution functions (PDF) uncertainties and its related uncertainties from the value of the strong coupling constant, and the uncertainties coming from the use of an effective field theory to simplify the hard calculation. We then move on to the study of the Higgs decay branching ratios which are also affected by diverse uncertainties. We will present the combination of the production cross sections and decay branching fractions in some specific cases which will show interesting consequences on the total theoretical uncertainties. We move on to present the results confronted to experiments and show that the theoretical uncertainties have a significant impact on the inferred limits either in the SM search for the Higgs boson or on the MSSM

  4. Dark matter phenomenology of SM and enlarged Higgs sectors extended with vector-like leptons

    Energy Technology Data Exchange (ETDEWEB)

    Angelescu, Andrei [Universite Paris-Saclay, CNRS, Laboratoire de Physique Theorique, Orsay (France); Arcadi, Giorgio [Max Planck Institut fuer Kernphysik, Heidelberg (Germany)

    2017-07-15

    We will investigate the scenario in which the Standard Model (SM) Higgs sector and its two-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the ''portal'' for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints coming purely from DM phenomenology with more general constraints like Electroweak Precision Test (EWPT) as well as with collider searches. In the case that the new fermionic sector interacts with the SM Higgs sector, constraints from DM phenomenology force the new states to lie above the TeV scale. This requirement is relaxed in the case of 2HDM. Nevertheless, strong constraints coming from EWPTs and the Renormalization Group Equations (RGEs) limit the impact of VLFs on collider phenomenology. (orig.)

  5. Dark matter phenomenology of SM and enlarged Higgs sectors extended with vector-like leptons.

    Science.gov (United States)

    Angelescu, Andrei; Arcadi, Giorgio

    2017-01-01

    We will investigate the scenario in which the Standard Model (SM) Higgs sector and its two-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints coming purely from DM phenomenology with more general constraints like Electroweak Precision Test (EWPT) as well as with collider searches. In the case that the new fermionic sector interacts with the SM Higgs sector, constraints from DM phenomenology force the new states to lie above the TeV scale. This requirement is relaxed in the case of 2HDM. Nevertheless, strong constraints coming from EWPTs and the Renormalization Group Equations (RGEs) limit the impact of VLFs on collider phenomenology.

  6. Phenomenology of the Higgs effective Lagrangian via FEYNRULES

    International Nuclear Information System (INIS)

    Alloul, Adam; Fuks, Benjamin; Sanz, Verónica

    2014-01-01

    The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of FEYNRULES and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of FEYNRULES capable to generate model files that can be understood by the MADGRAPH 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-Higgs production. We finally study contact interactions of gauge and Higgs bosons to fermions

  7. Phenomenology of the Higgs effective Lagrangian via FEYNRULES

    Energy Technology Data Exchange (ETDEWEB)

    Alloul, Adam [Groupe de Recherche de Physique des Hautes Énergies (GRPHE), Université de Haute-Alsace, IUT Colmar, 34 rue du Grillenbreit BP 50568, 68008 Colmar Cedex (France); Fuks, Benjamin [Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques,Université de Strasbourg/CNRS-IN2P3, 23 rue du Loess, F-67037 Strasbourg (France); Sanz, Verónica [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)

    2014-04-16

    The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of FEYNRULES and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of FEYNRULES capable to generate model files that can be understood by the MADGRAPH 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-Higgs production. We finally study contact interactions of gauge and Higgs bosons to fermions.

  8. Phenomenological analysis of Higgs boson production through gluon fusion in association with jets

    International Nuclear Information System (INIS)

    Greiner, Nicolas; Luisoni, Gionata; Winter, Jan-Christopher; Yundin, Valery; Schoenherr, Marek

    2015-06-01

    We present a detailed phenomenological analysis of the production of a Standard Model Higgs boson in association with up to three jets. We consider the gluon fusion channel using an effective theory in the large top-quark mass limit. Higgs boson production in gluon fusion constitutes an irreducible background to the vector boson fusion (VBF) process; hence the precise knowledge of its characteristics is a prerequisite for any measurement in the VBF channel. The calculation is carried out at next-to-leading order (NLO) in QCD in a fully automated way by combining the two programs GoSam and Sherpa. We present numerical results for a large variety of observables for both standard cuts and VBF selection cuts. We find that for all jet multiplicities the NLO corrections are sizeable. This is particularly true in the presence of kinematic selections enhancing the VBF topology, which are based on vetoing additional jet activity. In this case, precise predictions for the background can be made using our calculation by taking the difference between the inclusive H+2 jets and the inclusive H+3 jets result.

  9. Phenomenology of the Higgs Effective Lagrangian via FeynRules

    CERN Document Server

    Alloul, Adam; Sanz, Verónica

    2014-01-01

    The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of FeynRules and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of FeynRules capable to generate model files that can be understood by the MadGraph 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-...

  10. Leptogenesis, dark matter and Higgs phenomenology at TeV

    International Nuclear Information System (INIS)

    Gu, P.-H.; Sarkar, Utpal

    2008-01-01

    We propose an interesting model of neutrino masses to realize leptogenesis and dark matter at the TeV scale. A real scalar is introduced to naturally realize the Majorana masses of the right-handed neutrinos. We also include a new Higgs doublet that contributes to the dark matter of the universe. The neutrino masses come from the vacuum expectation value of the triplet Higgs scalar. The right-handed neutrinos are not constrained by the neutrino masses and hence they could generate leptogenesis at the TeV scale without subscribing to resonant leptogenesis. In our model, all new particles could be observable at the forthcoming Large Hardon Collider or the proposed future International Linear Collider

  11. Higgs boson theory and phenomenology mass measurements and nuclear physics Recent results from ISOLTRAP

    CERN Document Server

    Carena, M S; Herfurth, F; Ames, F; Audi, G; Beck, D; Blaum, K; Bollen, G; Kellerbauer, A G; Kluge, H J; Kuckein, M; Lunney, M D; Moore, R B; Oinonen, M; Rodríguez, D; Sauvan, E; Scheidenberger, C

    2003-01-01

    Precision electroweak data presently-favors a weakly-coupled Higgs sector as the mechanism responsible for electroweak symmetry breaking. Low-energy supersymmetry provides a natural framework for weakly-coupled elementary scalars. In this review, we summarize the theoretical properties of the Standard Model (SM) Higgs boson and the Higgs sector of the minimal super-symmetric extension of the Standard Model (MSSM). We then survey the phenomenology of the SM and MSSM Higgs bosons at the Tevatron, LHC and a future e**+e**- linear collider. We focus on the Higgs discovery potential of present and future colliders and stress the importance of precision measurements of Higgs boson properties. 459 Refs.31 The Penning trap mass spectrometer ISOLTRAP is a facility for high- precision mass measurements of short-lived radioactive nuclei installed at ISOLDE/CERN in Geneva. More than 200 masses have been measured with relative uncertainties of 1 multiplied by 10**-**7 or even close to 1 multiplied by 10**-**8 in special c...

  12. Unitarity and predictiveness in new Higgs inflation

    Science.gov (United States)

    Fumagalli, Jacopo; Mooij, Sander; Postma, Marieke

    2018-03-01

    In new Higgs inflation the Higgs kinetic terms are non-minimally coupled to the Einstein tensor, allowing the Higgs field to play the role of the inflaton. The new interaction is non-renormalizable, and the model only describes physics below some cutoff scale. Even if the unknown UV physics does not affect the tree level inflaton potential significantly, it may still enter at loop level and modify the running of the Standard Model (SM) parameters. This is analogous to what happens in the original model for Higgs inflation. A key difference, though, is that in new Higgs inflation the inflationary predictions are sensitive to this running. Thus the boundary conditions at the EW scale as well as the unknown UV completion may leave a signature on the inflationary parameters. However, this dependence can be evaded if the kinetic terms of the SM fermions and gauge fields are non-minimally coupled to gravity as well. Our approach to determine the model's UV dependence and the connection between low and high scale physics can be used in any particle physics model of inflation.

  13. Simplified models for Higgs physics: singlet scalar and vector-like quark phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Matthew J. [ARC Centre of Excellence for Particle Physics at the Terascale,School of Physics, University of Melbourne,Melbourne 3010 (Australia); Hewett, J.L. [SLAC National Accelerator Laboratory,Menlo Park 94025, CA (United States); Krämer, M. [Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University,D-52056 Aachen (Germany); Rizzo, T.G. [SLAC National Accelerator Laboratory,Menlo Park 94025, CA (United States)

    2016-07-08

    Simplified models provide a useful tool to conduct the search and exploration of physics beyond the Standard Model in a model-independent fashion. In this work we consider the complementarity of indirect searches for new physics in Higgs couplings and distributions with direct searches for new particles, using a simplified model which includes a new singlet scalar resonance and vector-like fermions that can mix with the SM top-quark. We fit this model to the combined ATLAS and CMS 125 GeV Higgs production and coupling measurements and other precision electroweak constraints, and explore in detail the effects of the new matter content upon Higgs production and kinematics. We highlight some novel features and decay modes of the top partner phenomenology, and discuss prospects for Run II.

  14. Large Hadron Collider (LHC) phenomenology, operational challenges and theoretical predictions

    CERN Document Server

    Gilles, Abelin R

    2013-01-01

    The Large Hadron Collider (LHC) is the highest-energy particle collider ever constructed and is considered "one of the great engineering milestones of mankind." It was built by the European Organization for Nuclear Research (CERN) from 1998 to 2008, with the aim of allowing physicists to test the predictions of different theories of particle physics and high-energy physics, and particularly prove or disprove the existence of the theorized Higgs boson and of the large family of new particles predicted by supersymmetric theories. In this book, the authors study the phenomenology, operational challenges and theoretical predictions of LHC. Topics discussed include neutral and charged black hole remnants at the LHC; the modified statistics approach for the thermodynamical model of multiparticle production; and astroparticle physics and cosmology in the LHC era.

  15. Phenomenology of on-shell Higgs production in the MSSM with complex parameters

    Energy Technology Data Exchange (ETDEWEB)

    Liebler, Stefan; Patel, Shruti; Weiglein, Georg

    2016-11-15

    A computation of inclusive cross sections for the production of neutral Higgs bosons through gluon fusion and bottom-quark annihilation is presented in the MSSM with complex parameters. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for the general case of arbitrary complex parameters which is supplemented by higher-order corrections. Massive top- and bottom-quark contributions are included at NLO QCD. In the effective theory of a heavy top-quark the top-quark contribution is taken into account up to N{sup 3}LO QCD in an expansion around the threshold of Higgs production for the CP-even component of the light Higgs boson. For the CP-odd component of the light Higgs boson and the heavy Higgs bosons the contributions in the effective field theory are incorporated up to NNLO QCD. Two-loop electroweak effects mediated through light quarks are also incorporated, and SUSY QCD corrections at NLO are interpolated from the MSSM with real parameters. Finite wave function normalisation factors for the external Higgs bosons ensuring the correct on-shell properties are incorporated from the code FeynHiggs. In the numerical analysis for the typical case of a strong admixture of the two heavy Higgs bosons it is demonstrated that squark effects are strongly dependent on the phases of the complex parameters, and the relevance of the resummation of squark effects in the bottom-quark Yukawa coupling is emphasised. The remaining theoretical uncertainties in the cross section predictions are discussed. The results have been implemented into an extension of the numerical code SusHi called SusHiMi.

  16. Phenomenology of on-shell Higgs production in the MSSM with complex parameters

    International Nuclear Information System (INIS)

    Liebler, Stefan; Patel, Shruti; Weiglein, Georg

    2016-11-01

    A computation of inclusive cross sections for the production of neutral Higgs bosons through gluon fusion and bottom-quark annihilation is presented in the MSSM with complex parameters. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for the general case of arbitrary complex parameters which is supplemented by higher-order corrections. Massive top- and bottom-quark contributions are included at NLO QCD. In the effective theory of a heavy top-quark the top-quark contribution is taken into account up to N"3LO QCD in an expansion around the threshold of Higgs production for the CP-even component of the light Higgs boson. For the CP-odd component of the light Higgs boson and the heavy Higgs bosons the contributions in the effective field theory are incorporated up to NNLO QCD. Two-loop electroweak effects mediated through light quarks are also incorporated, and SUSY QCD corrections at NLO are interpolated from the MSSM with real parameters. Finite wave function normalisation factors for the external Higgs bosons ensuring the correct on-shell properties are incorporated from the code FeynHiggs. In the numerical analysis for the typical case of a strong admixture of the two heavy Higgs bosons it is demonstrated that squark effects are strongly dependent on the phases of the complex parameters, and the relevance of the resummation of squark effects in the bottom-quark Yukawa coupling is emphasised. The remaining theoretical uncertainties in the cross section predictions are discussed. The results have been implemented into an extension of the numerical code SusHi called SusHiMi.

  17. Phenomenology of on-shell Higgs production in the MSSM with complex parameters

    Energy Technology Data Exchange (ETDEWEB)

    Liebler, Stefan; Patel, Shruti; Weiglein, Georg [DESY, Hamburg (Germany)

    2017-05-15

    A computation of inclusive cross sections for neutral Higgs boson production through gluon fusion and bottom-quark annihilation is presented in the MSSM with complex parameters. The predictions for the gluon-fusion process are based on an explicit calculation of the leading-order cross section for arbitrary complex parameters which is supplemented by higher-order corrections: massive top- and bottom-quark contributions at NLO QCD, in the heavy top-quark effective theory the top-quark contribution up to N{sup 3}LO QCD including a soft expansion for the CP-even component of the light Higgs boson. For its CP-odd component and the heavy Higgs bosons the contributions are incorporated up to NNLO QCD. Two-loop electroweak effects are also incorporated, and SUSY QCD corrections at NLO are interpolated from the MSSM with real parameters. Finite wave function normalisation factors ensuring correct on-shell properties of the external Higgs bosons are incorporated from the code FeynHiggs. For the typical case of a strong admixture of the two heavy Higgs bosons it is demonstrated that squark effects are strongly dependent on the phases of the complex parameters. The remaining theoretical uncertainties for cross sections are discussed. The results have been implemented into an extension of the numerical code SusHi called SusHiMi. (orig.)

  18. Brane-Higgs-boson phenomenology in five-dimensional warped supersymmetry

    International Nuclear Information System (INIS)

    Bouchart, Charles; Moreau, Gregory; Knochel, Alexander

    2011-01-01

    Constructing supersymmetric extensions of higher-dimensional models can have several motivations; it is, for instance, necessary in the context of string theories. Studying the supersymmetric version of the well-motivated model proposed by Randall and Sundrum, with the Higgs boson localized on the so-called TeV-brane, is not trivial since singularities appear in the Higgs couplings. Those are regularized by the contribution from the exchange of infinite towers of Kaluza-Klein (KK) scalar modes with Dirichlet-Dirichlet boundary conditions. Here we first derive the regularized four-dimensional (4D) effective Higgs couplings and induced sfermion mass matrices. A general method is provided for this regularization, based on the completeness relation. The sfermion masses must be obtained either from integrating out the mentioned KK towers or by treating their mixing effects, depending on the cases. We then use the obtained Higgs couplings and sfermion masses for some phenomenological applications. On one side, we show at the one-loop level how all quadratic divergences in the Higgs mass cancel out for any cutoff, due to 5D supersymmetry (SUSY) and to 5D anomaly cancellation; the analytical way followed here also allows a justification of the infinite KK summation required for the so-called KK regularization in 5D SUSY, which has motivated a rich literature. On the other side, we show that a certain pattern of SUSY breaking in the bulk would allow one to distinguish experimentally the minimal SUSY model a la Randall and Sundrum with bulk matter from the minimal 4D SUSY model, in the scenario where only superpartners were produced at the Large Hadron Collider. In this SUSY-breaking context, two of the discriminating tests developed make use of some different features arising in the squark or slepton mass spectrum. The other distinctive supersymmetric Randall-Sundrum feature is the possibly larger (even dominant) Higgs boson decay branching ratios into sleptons, compared to

  19. Combining resummed Higgs predictions across jet bins

    Energy Technology Data Exchange (ETDEWEB)

    Boughezal, Radja [Argonne National Laboratory, IL (United States). High Energy Physics Division; Liu, Xiaohui; Petriello, Frank [Argonne National Laboratory, IL (United States). High Energy Physics Division; Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Walsh, Jonathan R. [California Univ., Berkeley, CA (United States). Ernest Orlando Lawrence Berkeley Laboratory; California Univ., Berkeley, CA (United States). Center for Theoretical Physics

    2013-12-15

    Experimental analyses often use jet binning to distinguish between different kinematic regimes and separate contributions from background processes. To accurately model theoretical uncertainties in these measurements, a consistent description of the jet bins is required. We present a complete framework for the combination of resummed results for production processes in different exclusive jet bins, focusing on Higgs production in gluon fusion as an example. We extend the resummation of the H+1-jet cross section into the challenging low transverse momentum region, lowering the uncertainties considerably. We provide combined predictions with resummation for cross sections in the H+0-jet and H+1-jet bins, and give an improved theory covariance matrix for use in experimental studies. We estimate that the relevant theoretical uncertainties on the signal strength in the H{yields}WW{sup *} analysis are reduced by nearly a factor of 2 compared to the current value.

  20. Predictions of the Higgs mass and the weak mixing angle in the 6D gauge-Higgs unification

    International Nuclear Information System (INIS)

    Hasegawa, Kouhei; Lim, Chong-Sa; Maru, Nobuhito

    2016-01-01

    In the gauge-Higgs unification with multiple extra spaces, the Higgs self-coupling is on the order of g 2 and the Higgs boson is predicted to be light, being consistent with the LHC results. When the gauge group is simple, the weak mixing angle is also predictable. We address a question on whether there exists a model of gauge-Higgs unification in six-dimensional space-time, which successfully predicts the mass ratios of the Higgs boson and weak gauge bosons. First, using a useful formula, we give a general argument on the condition for obtaining a realistic prediction of the weak mixing angle sin 2 θ W = 1/4, and find that triplet and sextet representations of the minimal SU(3) gauge group lead to the realistic prediction. Concerning the Higgs mass, we notice that, in the models with one Higgs doublet, the predicted Higgs mass is always the same: M H = 2M W . However, by extending our discussion to the models with two Higgs doublets, the situation changes: we obtain an interesting prediction M H ≤ 2M W at the leading order of the perturbation. Thus, it is possible to recover the observed Higgs mass, 125 GeV, for a suitable choice of the parameter. The situation is in clear contrast to the case of the minimal supersymmetric standard model, where M H ≤ M Z at the classical level and the predicted Higgs mass cannot recover the observed value. (author)

  1. Modified Higgs boson phenomenology from gauge or gaugino mediation in the next-to-minimal supersymmetric standard model

    International Nuclear Information System (INIS)

    Morrissey, David E.; Pierce, Aaron

    2008-01-01

    In the next-to-minimal supersymmetric standard model (NMSSM), the presence of light pseudoscalars can have a dramatic effect on the decays of the standard model-like Higgs boson. These pseudoscalars are naturally light if supersymmetry breaking preserves an approximate U(1) R symmetry, spontaneously broken when the Higgs bosons take on their expectation values. We investigate two classes of theories that possess such an approximate U(1) R at the mediation scale: modifications of gauge and gaugino mediation. In the models we consider, we find two disjoint classes of phenomenologically allowed parameter regions. One of these regions corresponds to a limit where the singlet of the NMSSM largely decouples. The other can give rise to a standard model-like Higgs boson with dominant branching into light pseudoscalars.

  2. A phenomenological study on the production of Higgs bosons in the cSMCS model at the LHC

    Directory of Open Access Journals (Sweden)

    N. Darvishi

    2017-10-01

    Full Text Available In the present work, we intend to predict the production rates of the Higgs bosons in the simplest extension of the Standard Model (SM by a neutral complex singlet (cSMCS. This model has an additional source of CP violation and provides strong enough first-order electroweak phase transition to generate the baryon asymmetry of universe (BAU. The scalar spectrum of the cSMCS includes three neutral Higgs particles with the lightest one considered to be the 125 GeV Higgs boson found at LHC. The SM-like Higgs boson comes mostly from the SM-like SU(2 doublet, with a small correction from the singlet. To predict the production rates of the Higgs bosons, we use a conventional effective LO QCD framework and the unintegrated parton distribution functions (UPDF of Kimber–Martin–Ryskin (KMR. We first compute the SM Higgs production cross-section and compare the results to the existing theoretical calculations from different frameworks as well as the experimental data from the CMS and ATLAS collaborations. It is shown that our framework is capable of producing sound predictions for these high-energy QCD events in the SM. Afterwards we present our predictions for the Higgs boson production in the cSMCS.

  3. Precise predictions within the two-Higgs-doublet model

    International Nuclear Information System (INIS)

    Altenkamp, Lukas

    2017-01-01

    We consider the Two-Higgs-Doublet Model (THDM) where the Standard Model (SM) field content is extended by adding a further Higgs-boson doublet. This results in five Higgs bosons, two CP-even, one CP-odd and a charged Higgs boson and it's anti-particle. In order to provide accurate and reliable predictions within this model, next-to-leading order calculations are necessary. To this end, we perform a renormalization procedure and adopt four new renormalization schemes. The counterterm Feynman rules as well as the renormalization conditions are implemented into an FeynArts model file, yielding the possibility to generate amplitudes and squared matrix elements for arbitrary processes which is a major contribution to the automation of higher-order calculations. As an application we investigate the decay of a light, CP-even, SM-like Higgs boson into four fermions in the THDM. To this end, we extend the program Prophecy4f and compute the partial decay widths for different benchmark scenarios. For all investigated scenarios, we observe that the THDM widths are bounded by the SM widths and that the deviations are larger at higher order. The renormalization group equations have been solved in order to investigate the renormalization scale dependence which gives an estimate of the theoretical uncertainty arising due to the truncation of the perturbation series. By comparing the results of different renormalization schemes we determine for which parameter regions each scheme provides reliable predictions.

  4. Precise predictions within the two-Higgs-doublet model

    Energy Technology Data Exchange (ETDEWEB)

    Altenkamp, Lukas

    2017-02-21

    We consider the Two-Higgs-Doublet Model (THDM) where the Standard Model (SM) field content is extended by adding a further Higgs-boson doublet. This results in five Higgs bosons, two CP-even, one CP-odd and a charged Higgs boson and it's anti-particle. In order to provide accurate and reliable predictions within this model, next-to-leading order calculations are necessary. To this end, we perform a renormalization procedure and adopt four new renormalization schemes. The counterterm Feynman rules as well as the renormalization conditions are implemented into an FeynArts model file, yielding the possibility to generate amplitudes and squared matrix elements for arbitrary processes which is a major contribution to the automation of higher-order calculations. As an application we investigate the decay of a light, CP-even, SM-like Higgs boson into four fermions in the THDM. To this end, we extend the program Prophecy4f and compute the partial decay widths for different benchmark scenarios. For all investigated scenarios, we observe that the THDM widths are bounded by the SM widths and that the deviations are larger at higher order. The renormalization group equations have been solved in order to investigate the renormalization scale dependence which gives an estimate of the theoretical uncertainty arising due to the truncation of the perturbation series. By comparing the results of different renormalization schemes we determine for which parameter regions each scheme provides reliable predictions.

  5. Phenomenology of the Higgs effective Lagrangian via F eynR ules

    Science.gov (United States)

    Alloul, Adam; Fuks, Benjamin; Sanz, Verónica

    2014-04-01

    The Higgs discovery and the lack of any other hint for new physics favor a description of non-standard Higgs physics in terms of an effective field theory. We present an implementation of a general Higgs effective Lagrangian containing operators up to dimension six in the framework of F eynR ules and provide details on the translation between the mass and interaction bases, in particular for three- and four-point interaction vertices involving Higgs and gauge bosons. We illustrate the strengths of this implementation by using the UFO interface of F eynR ules capable to generate model files that can be understood by the M adG raph 5 event generator and that have the specificity to contain all interaction vertices, without any restriction on the number of external legs or on the complexity of the Lorentz structures. We then investigate several new physics effects in total rates and differential distributions for different Higgs production modes, including gluon fusion, associated production with a gauge boson and di-Higgs production. We finally study contact interactions of gauge and Higgs bosons to fermions.

  6. On the phenomenology of charged Higgs bosons in the complex MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Thi Nhung Dao

    2012-02-16

    In this thesis, we study various decay and production processes of charged Higgs bosons at the Large Hadron Collider (LHC) in the context of a general complex Minimal Supersymmetric Standard Model (MSSM) with minimal flavor violation. We investigate the effect of the complex phases of the soft supersymmetry breaking parameters and of the Higgsino mixing parameter, {mu}, on the decay widths and production rates. The CP violating asymmetries induced by those phases are also considered. The calculations are done at the one-loop level. This is nontrivial since there are a large number of Feynman diagrams and various types of singularities (UV divergences, soft and collinear singularities, threshold singularities). We discuss in detail our calculation method and how to handle those divergences. In particular, the topic of one-loop renormalization and neutral-Higgs mixing effects in the complex MSSM for processes involving Higgs bosons are addressed. The higher order corrections to the decay of charged Higgs bosons into aW-boson and the lightest neutral Higgs boson are calculated and shown to be significantly large. The CP asymmetry arising from all complex phases is considered, especially from the top-quark trilinear coupling, A{sub t}, and {mu}, which induce a large contribution to the CP asymmetry. We perform a complete calculation of the next-to-leading order (NLO) electroweak (EW) corrections to the charged Higgs production in association with a W-boson via the bb annihilation channel and a consistent combination with other contributions including the standard and supersymmetric-QCD corrections and the gg fusion, with resummation of the leading radiative corrections to the bottom-Higgs couplings and the neutral Higgs-boson propagators. We observe a strong dependence of the production rates on the phases of A{sub t} and of the gluino-mass parameter M{sub 3} and a large CP asymmetry arising mainly from the gg fusion. The NLO EW corrections to the charged Higgs

  7. Precision predictions for Higgs differential distributions at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Markus

    2017-08-15

    After the discovery of a Standard-Model-like Higgs boson at the LHC a central aspect of the LHC physics program is to study the Higgs boson's couplings to Standard Model particles in detail in order to elucidate the nature of the Higgs mechanism and to search for hints of physics beyond the Standard Model. This requires precise theory predictions for both inclusive and differential Higgs cross sections. In this thesis we focus on the application of resummation techniques in the framework of Soft-Collinear Effective Theory (SCET) to obtain accurate predictions with reliable theory uncertainties for various observables. We first consider transverse momentum distributions, where the resummation of large logarithms in momentum (or distribution) space has been a long-standing open question. We show that its two-dimensional nature leads to additional difficulties not observed in one-dimensional observables such as thrust, and solving the associated renormalization group equations (RGEs) in momentum space thus requires a very careful scale setting. This is achieved using distributional scale setting, a new technique to solve differential equations such as RGEs directly in distribution space, as it allows one to treat logarithmic plus distributions like ordinary logarithms. We show that the momentum space solution fundamentally differs from the standard resummation in Fourier space by different boundary terms to all orders in perturbation theory and hence provides an interesting and complementary approach to obtain new insight into the all-order perturbative and nonperturbative structure of transverse momentum distributions. Our work lays the ground for a detailed numerical study of the momentum space resummation. We then show that in the case of a discovery of a new heavy color-singlet resonance such as a heavy Higgs boson, one can reliably and model-independently infer its production mechanism by dividing the data into two mutually exclusive jet bins. The method is

  8. Phenomenology of a very light scalar (100 MeV Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Jackson D.; Foot, Robert; Volkas, Raymond R. [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, University of Melbourne, VIC 3010 (Australia)

    2014-02-27

    In this paper we investigate the phenomenology of a very light scalar, h, with mass 100 MeV Higgs. As a benchmark model we take the real singlet scalar extension of the SM. We point out apparently unresolved uncertainties in the branching ratios and lifetime of h in a crucial region of parameter space for LHC phenomenology. Bounds from LEP, meson decays and fixed target experiments are reviewed. We also examine prospects at the LHC. For m{sub h}≲m{sub B} the dominant production mechanism is via meson decay; our main result is the calculation of the differential p{sub T} spectrum of h scalars originating from B mesons and the subsequent prediction of up to thousands of moderate (triggerable) p{sub T} displaced dimuons possibly hiding in the existing dataset at ATLAS/CMS or at LHCb. We also demonstrate that the subdominant Vh production channel has the best sensitivity for m{sub h}≳m{sub B} and that future bounds in this region could conceivably compete with those of LEP.

  9. Higgs, Top, and Bottom Mass Predictions in Finite Unified Theories

    CERN Document Server

    Heinemeyer, Sven; Zoupanos, George

    2014-01-01

    All-loop Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) based on the principle of reduction of couplings, which have a remarkable predictive power. The reduction of couplings implies the existence of renormalization group invariant relations among them, which guarantee the vanishing of the beta functions at all orders in perturbation theory in particular N = 1 GUTs. In the soft breaking sector these relations imply the existence of a sum rule among the soft scalar masses. The confrontation of the predictions of a SU(5) FUT model with the top and bottom quark masses and other low-energy experimental constraints leads to a prediction of the light Higgs-boson mass in the rangeMh ∼ 121−126 GeV, in remarkable agreement with the discovery of the Higgs boson with a mass around ∼ 125.7 GeV. Also a relatively heavy spectrum with coloured supersymmetric particles above ∼ 1.5 TeV is predicted, consistent with the non-observation of those particles at the LHC.

  10. Time-dependent fatigue--phenomenology and life prediction

    International Nuclear Information System (INIS)

    Coffin, L.F.

    1979-01-01

    The time-dependent fatigue behavior of materials used or considered for use in present and advanced systems for power generation is outlined. A picture is first presented to show how basic mechanisms and phenomenological information relate to the performance of the component under consideration through the so-called local strain approach. By this means life prediction criteria and design rules can be formulated utilizing laboratory test information which is directly translated to predicting the performance of a component. The body of phenomenological information relative to time-dependent fatigue is reviewed. Included are effects of strain range, strain rate and frequency, environment and wave shape, all of which are shown to be important in developing both an understanding and design base for time dependent fatigue. Using this information, some of the current methods being considered for the life prediction of components are reviewed. These include the current ASME code case, frequency-modified fatigue equations, strain range partitioning, the damage function method, frequency separation and damage rate equations. From this review, it is hoped that a better perspective on future directions for basic material science at high temperature can be achieved

  11. Constraints on TeV scale Majorana neutrino phenomenology from the vacuum stability of the Higgs

    International Nuclear Information System (INIS)

    Chakraborthy, Jaydeep; Das, Moumita; Mohanty, Subhendra

    2013-01-01

    The vacuum stability condition of the Standard Model Higgs potential with mass in the range of 124-127 GeV puts an upper bound on the Dirac mass of the neutrinos. We study this constraint with the right-handed neutrino masses upto TeV scale. The heavy neutrinos contribute to ΔL = 2 processes like neutrinoless double beta decay and same-sign-dilepton production in the colliders. The vacuum stability criterion also restricts the light-heavy neutrino mixing and constrains the branching ratio of lepton flavour violating process, like μ → eγ mediated by the heavy neutrinos. We show that neutrinoless double beta decay with a lifetime ∼ 10 25 years can be observed if the the lightest heavy neutrino mass is R > 3.3 TeV. Finally we show that the observation of same-sign-dileptons (SSD) associated with jets at the LHC needs much larger luminosity than available at present. We have estimated the possible maximum cross-section for this process at the LHC and show that with an integrated luminosity 100 fb 1 it may be possible to observe the SSD signals as long as M R < 400 GeV. (author)

  12. HiggsBounds 2.0.0. Confronting neutral and charged Higgs sector predictions with exclusion bounds from LEP and the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, P.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, O. [Freiburg Univ. (Germany). Physikalisches Inst.; Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Williams, K.E. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics

    2011-03-15

    HiggsBounds 2.0.0 is a computer code which tests both neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from the Higgs searches at LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. HiggsBounds 2.0.0 then uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 represents a significant extension of the code since its first release (1.0.0). It includes now 28/53 LEP/Tevatron Higgs search analyses, compared to the 11/22 in the first release, of which many of the ones from the Tevatron are replaced by updates. As a major extension, the code allows now the predictions for (singly) charged Higgs bosons to be confronted with LEP and Tevatron searches. Furthermore, the newly included analyses contain LEP searches for neutral Higgs bosons (H) decaying invisibly or into (non flavour tagged) hadrons as well as decay-mode independent searches for neutral Higgs bosons, LEP searches via the production modes {tau}{sup +}{tau}{sup -}H and b anti bH, and Tevatron searches via t anti tH. Also, all Tevatron results presented at the ICHEP'10 are included in version 2.0.0. As physics applications of HiggsBounds 2.0.0 we study the allowed Higgs mass range for model scenarios with invisible Higgs decays and we obtain exclusion results for the scalar sector of the Randall-Sundrum model using up-to-date LEP and Tevatron direct search results. (orig.)

  13. Handbook of LHC Higgs Cross Sections: 3. Higgs Properties

    Energy Technology Data Exchange (ETDEWEB)

    Heinemeyer, S; et al.

    2013-01-01

    This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered particle such as couplings to SM particles, spin and CP-quantum numbers etc.

  14. Phenomenological models of elastic nucleon scattering and predictions for LHC

    CERN Document Server

    Kundrat, V; Lokajicek, M; Prochazka, J

    2011-01-01

    The hitherto analyses of elastic collisions of charged nucleons involving common influence of Coulomb and hadronic scattering have been based practically on West and Yennie formula. However, this approach has been shown recently to be inadequate from experimental as well as theoretical points of view. The eikonal model enabling to determine physical characteristics in impact parameter space seems to be more pertinent. The contemporary phenomenological models admit, of course, different distributions of collision processes in the impact parameter space and cannot give any definite answer. Nevertheless, some predictions for the planned LHC energy that have been given on their basis may be useful, as well as the possibility of determining the luminosity from elastic scattering. (C) 2010 Elsevier B.V. All rights reserved.

  15. Search for Higgs bosons predicted in two-Higgs-doublet models via decays to tau lepton pairs in 1.96 TeV pp collisions.

    Science.gov (United States)

    Aaltonen, T; Adelman, J; Akimoto, T; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'Orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; Di Canto, A; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Garosi, P; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Group, R C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; LeCompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; MacQueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Renz, M; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Rutherford, B; Saarikko, H; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Trovato, M; Tsai, S-Y; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wagner-Kuhr, J; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Weinelt, J; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Würthwein, F; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

    2009-11-13

    We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using 1.8 fb(-1) of integrated luminosity of pp collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional space of tanbeta versus m(A) (the ratio of the vacuum expectation values of the two Higgs doublets and the mass of the pseudoscalar boson, respectively).

  16. Higgs, di-Higgs and tri-Higgs production via SUSY processes at the LHC with 14 TeV

    NARCIS (Netherlands)

    van Beekveld, M.; Beenakker, W.; Caron, S.; Castelijn, R.; Lanfermann, M.; Struebig, A.

    2015-01-01

    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

  17. Matching uncertainties in the prediction of the Higgs boson transverse momentum in the SM and beyond

    International Nuclear Information System (INIS)

    Bagnaschi, Emanuele

    2016-09-01

    We present the results of our recent study of the theoretical uncertainties that affect the predictions for the Higgs-boson transverse-momentum in gluon fusion when fixed- and all-order results are matched. Our investigation consists of a twofold analysis: first we present a detailed comparison of two recently introduced prescriptions for the determination of the matching scale, then we apply the results of these methods to three widely used matching frameworks, namely the aMC rate at NLO and POWHEG Monte Carlo approaches and analytic resummation. The results of our study are applied to the production of the SM Higgs boson and of the neutral Higgs bosons of the Two-Higgs-Doublet Model in a variety of scenarios.

  18. Four Generations in Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Kribs, Graham D. [Department of Physics, University of Oregon, Eugene, OR 97403 (United States); Plehn, Tilman [SUPA, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, Scotland (HCP speaker) (United Kingdom); Spannowsky, Michael [ASC, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, 80333 Muenchen (Germany); Tait, Tim M.P. [HEP Division, Argonne National Laboratory, 9700 Cass Ave., Argonne, IL 60439 (United States)

    2008-03-15

    In four-generation models Higgs masses of 115-315 GeV are perfectly allowed by electroweak precision data. In this mass range we find dramatic effects on Higgs phenomenology at hadron colliders: production rates are enhanced, weak-boson-fusion channels are suppressed, angular distributions are modified, Higgs pairs can be observed, and Higgs decays to Majorana neutrinos can lead to exotic signals.

  19. High-precision predictions for the light CP-even Higgs boson mass of the MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, T.; Hollik, W. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Rzehak, H. [Freiburg Univ. (Germany). Physikalisches Inst.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2014-03-15

    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 realised in the Standard Model (SM) and its most commonly studied extension, the Minimal Supersymmetric SM (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, M{sub h}, 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 M{sub h} 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.

  20. Higgs physics

    International Nuclear Information System (INIS)

    Rindani, Saurabh D.

    2002-07-01

    Higgs physics is at present poised at an interesting juncture, when a light Higgs boson of the standard model (henceforth to be referred to as SM), a spin-zero particle which would signal spontaneous gauge symmetry breaking in the simplest form, has not been seen until the conclusion of experiments at LEP and LEP2 electron-positron collider at CERN, Geneva. From a theoretical point of view, the developments until the present time are complex and interesting. While some of the basic principles underlying spontaneous symmetry breaking of gauge symmetry and the Higgs mechanism are now commonly known, the actual realization of this mechanism in nature is still a subject of investigation. The mass of the SM Higgs boson is an unknown parameter and the phenomenology is sensitively dependent on the mass. Thus the properties and discovery strategies for the Higgs vary greatly depending on the supposed mass, and the phenomenology rapidly gets complex as the range of the Higgs mass is increased. Branching rations for various channels and the total decay width are shown as a function of the Higgs mass. We can get the total width of the Higgs by adding up all the decay channels. Up to masses of about 140 GeV, the Higgs is very narrow, Γ(H) H ∼ 200 GeV. The width cannot be measured directly in the intermediate mass region at LHC or e + e - colliders. However, it could be measured at μ + μ - colliders. Above a mass of about 250 GeV, the state is wide enough to be observable, in general. Above the two-vector-boson threshold, the width is Γ(H) ∼ 1/2m H 3 (TeV). For m H ∼ 1 TeV, Γ H ∼ 1/2 TeV. (author)

  1. Higgs couplings and supersymmetry in the light of early LHC results

    International Nuclear Information System (INIS)

    Stefaniak, Tim

    2014-07-01

    We present phenomenological studies investigating the implications of early results from the Large Hadron Collider (LHC) for models beyond the Standard Model (BSM), mostly focusing on Supersymmetry (SUSY). Our work covers different aspects in this wide field of research. We describe the development and basic concepts of the public computer codes HiggsBounds (version 4) and HiggsSignals. These confront the Higgs sector predictions of BSM models with results from LEP, Tevatron and LHC Higgs searches. While HiggsBounds tests the model against experimental null-results, HiggsSignals evaluates the model's chi-squared compatibility with the signal rate and mass measurements of the Higgs boson, that was discovered by the LHC in 2012. We then perform a systematic study of potential deviations in the Higgs couplings from their Standard Model (SM) prediction. No significant deviations are found. Future capabilities of Higgs coupling determination at the later LHC stages and at the International Linear Collider (ILC) are explored. We also study the implications of the Higgs discovery for the Minimal Supersymmetric Standard Model (MSSM), considering either the light or the heavy CP-even Higgs boson as the discovered state. We show that both interpretations are viable and discuss their phenomenology. Finally, we study the LHC signatures of resonant scalar lepton production, which may arise in SUSY models with R-parity violation (RPV). These are confronted with early LHC results, yielding constraints on the relevant RPV operators.

  2. Phenomenology of induced electroweak symmetry breaking

    International Nuclear Information System (INIS)

    Chang, Spencer; Galloway, Jamison; Luty, Markus A.; Salvioni, Ennio; Tsai, Yuhsin

    2015-01-01

    We study the phenomenology of models of electroweak symmetry breaking where the Higgs potential is destabilized by a tadpole arising from the coupling to an “auxiliary” Higgs sector. The auxiliary Higgs sector can be either perturbative or strongly coupled, similar to technicolor models. Since electroweak symmetry breaking is driven by a tadpole, the cubic and quartic Higgs couplings can naturally be significantly smaller than their values in the standard model. The theoretical motivation for these models is that they can explain the 125 GeV Higgs mass in supersymmetry without fine-tuning. The auxiliary Higgs sector contains additional Higgs states that cannot decouple from standard model particles, so these models predict a rich phenomenology of Higgs physics beyond the standard model. In this paper we analyze a large number of direct and indirect constraints on these models. We present the current constraints after the 8 TeV run of the LHC, and give projections for the sensitivity of the upcoming 14 TeV run. We find that the strongest constraints come from the direct searches A 0 →Zh, A 0 →tt-bar, with weaker constraints from Higgs coupling fits. For strongly-coupled models, additional constraints come from ρ + →WZ where ρ + is a vector resonance. Our overall conclusion is that a significant parameter space for such models is currently open, allowing values of the Higgs cubic coupling down to 0.4 times the standard model value for weakly coupled models and vanishing cubic coupling for strongly coupled models. The upcoming 14 TeV run of the LHC will stringently test this scenario and we identify several new searches with discovery potential for this class of models.

  3. Higgs and superparticle mass predictions from the landscape

    Science.gov (United States)

    Baer, Howard; Barger, Vernon; Serce, Hasan; Sinha, Kuver

    2018-03-01

    Predictions for the scale of SUSY breaking from the string landscape go back at least a decade to the work of Denef and Douglas on the statistics of flux vacua. The assumption that an assortment of SUSY breaking F and D terms are present in the hidden sector, and their values are uniformly distributed in the landscape of D = 4, N = 1 effective supergravity models, leads to the expectation that the landscape pulls towards large values of soft terms favored by a power law behavior P( m soft) ˜ m soft n . On the other hand, similar to Weinberg's prediction of the cosmological constant, one can assume an anthropic selection of weak scales not too far from the measured value characterized by m W,Z,h ˜ 100 GeV. Working within a fertile patch of gravity-mediated low energy effective theories where the superpotential μ term is ≪ m 3/2, as occurs in models such as radiative breaking of Peccei-Quinn symmetry, this biases statistical distributions on the landscape by a cutoff on the parameter ΔEW, which measures fine-tuning in the m Z - μ mass relation. The combined effect of statistical and anthropic pulls turns out to favor low energy phenomenology that is more or less agnostic to UV physics. While a uniform selection n = 0 of soft terms produces too low a value for m h , taking n = 1 and 2 produce most probabilistically m h ˜ 125 GeV for negative trilinear terms. For n ≥ 1, there is a pull towards split generations with {m}_{\\tilde{q},\\tilde{ℓ}}(1,2)˜ 10-30 TeV whilst {m}_{{\\tilde{t}}_1}˜ 1-2 TeV . The most probable gluino mass comes in at ˜ 3 - 4 TeV — apparently beyond the reach of HL-LHC (although the required quasi-degenerate higgsinos should still be within reach). We comment on consequences for SUSY collider and dark matter searches.

  4. Handbook of LHC Higgs Cross Sections: 3. Higgs Properties Report of the LHC Higgs Cross Section Working Group

    CERN Document Server

    Heinemeyer, S; Passarino, G; Tanaka, R; Andersen, J R; Artoisenet, P; Bagnaschi, E A; Banfi, A; Becher, T; Bernlochner, F U; Bolognesi, S; Bolzoni, P; Boughezal, R; Buarque, D; Campbell, J; Caola, F; Carena, M; Cascioli, F; Chanon, N; Cheng, T; Choi, S Y; David, A; de Aquino, P; Degrassi, G; Del Re, D; Denner, A; van Deurzen, H; Diglio, S; Di Micco, B; Di Nardo, R; Dittmaier, S; Dührssen, M; Ellis, R K; Ferrera, G; Fidanza, N; Flechl, M; de Florian, D; Forte, S; Frederix, R; Frixione, S; Gangal, S; Gao, Y; Garzelli, M V; Gillberg, D; Govoni, P; Grazzini, M; Greiner, N; Griffiths, J; Gritsan, A V; Grojean, C; Hall, D C; Hays, C; Harlander, R; Hernandez-Pinto, R; Höche, S; Huston, J; Jubb, T; Kadastik, M; Kallweit, S; Kardos, A; Kashif, L; Kauer, N; Kim, H; Klees, R; Krämer, M; Krauss, F; Laureys, A; Laurila, S; Lehti, S; Li, Q; Liebler, S; Liu, X; Logan, E; Luisoni, G; Malberti, M; Maltoni, F; Mawatari, K; Maierhoefer, F; Mantler, H; Martin, S; Mastrolia, P; Mattelaer, O; Mazzitelli, J; Mellado, B; Melnikov, K; Meridiani, P; Miller, D J; Mirabella, E; Moch, S O; Monni, P; Moretti, N; Mück, A; Mühlleitner, M; Musella, P; Nason, P; Neu, C; Neubert, M; Oleari, C; Olsen, J; Ossola, G; Peraro, T; Peters, K; Petriello, F; Piacquadio, G; Potter, C T; Pozzorini, S; Prokofiev, K; Puljak, I; Rauch, M; Rebuzzi, D; Reina, L; Rietkerk, R; Rizzi, A; Rotstein-Habarnau, Y; Salam, G P; Sborlini, G; Schissler, F; Schönherr, M; Schulze, M; Schumacher, M; Siegert, F; Slavich, P; Smillie, J M; Stål, O; von Soden-Fraunhofen, J F; Spira, M; Stewart, I W; Tackmann, F J; Taylor, P T E; Tommasini, D; Thompson, J; Thorne, R S; Torrielli, P; Tramontano, F; Tran, N V; Trócsányi, Z; Ubiali, M; Vazquez Acosta, M; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Wagner, C; Walsh, J R; Wang, J; Weiglein, G; Whitbeck, A; Williams, C; Yu, J; Zanderighi, G; Zanetti, M; Zaro, M; Zerwas, P M; Zhang, C; Zirke, T J E; Zuberi, S

    2013-01-01

    This Report summarizes the results of the activities in 2012 and the first half of 2013 of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. This report follows the first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) and the second working group report Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002). After the discovery of a Higgs boson at the LHC in mid-2012 this report focuses on refined prediction of Standard Model (SM) Higgs phenomenology around the experimentally observed value of 125-126 GeV, refined predictions for heavy SM-like Higgs bosons as well as predictions in the Minimal Supersymmetric Standard Model and first steps to go beyond these models. The other main focus is on the extraction of the characteristics and properties of the newly discovered p...

  5. Towards precise predictions for Higgs-boson production in the MSSM

    CERN Document Server

    Bagnaschi, E; Liebler, S; Mantler, H; Slavich, P; Vicini, A

    2014-01-01

    We study the production of scalar and pseudoscalar Higgs bosons via gluon fusion and bottom-quark annihilation in the MSSM. Relying on the NNLO-QCD calculation implemented in the public code SusHi, we provide precise predictions for the Higgs-production cross section in six benchmark scenarios compatible with the LHC searches. We also provide a detailed discussion of the sources of theoretical uncertainty in our calculation. We examine the dependence of the cross section on the renormalization and factorization scales, on the precise definition of the Higgs-bottom coupling and on the choice of PDFs, as well as the uncertainties associated to our incomplete knowledge of the SUSY contributions through NNLO. In particular, a potentially large uncertainty originates from uncomputed higher-order QCD corrections to the bottom-quark contributions to gluon fusion.

  6. Higgs boson hunting

    International Nuclear Information System (INIS)

    Dawson, S.; Haber, H.E.; Rindani, S.D.

    1989-05-01

    This is the summary report of the Higgs Boson Working Group. We discuss a variety of search techniques for a Higgs boson which is lighter than the Z. The processes K → πH, η prime → ηH,Υ → Hγ and e + e - → ZH are examined with particular attention paid to theoretical uncertainties in the calculations. We also briefly examine new features of Higgs phenomenology in a model which contains Higgs triplets as well as the usual doublet of scalar fields. 33 refs., 6 figs., 1 tab

  7. arXiv Addendum to: Predictions for Higgs production at the Tevatron and the associated uncertainties

    CERN Document Server

    Baglio, Julien

    2010-01-01

    We update the theoretical predictions for the production cross sections of the Standard Model Higgs boson at the Fermilab Tevatron collider, focusing on the two main search channels, the gluon-gluon fusion mechanism $gg \\to H$ and the Higgs-strahlung processes $q \\bar q \\to VH$ with $V=W/Z$, including all relevant higher order QCD and electroweak corrections in perturbation theory. We then estimate the various uncertainties affecting these predictions: the scale uncertainties which are viewed as a measure of the unknown higher order effects, the uncertainties from the parton distribution functions and the related errors on the strong coupling constant, as well as the uncertainties due to the use of an effective theory approach in the determination of the radiative corrections in the $gg \\to H$ process at next-to-next-to-leading order. We find that while the cross sections are well under control in the Higgs--strahlung processes, the theoretical uncertainties are rather large in the case of the gluon-gluon fus...

  8. Precise predictions of higgs boson decays including the full one-loop corrections in supersymmetry

    International Nuclear Information System (INIS)

    Frisch, W.

    2011-01-01

    The Standard Model of elementary particle physics is a highly successful theory, describing the electromagnetic, strong and weak interaction of matter particles up to energy scales to a few hundred giga electronvolt. Despite its great success in explaining experimental results correctly, there is hardly no doubt that the SM is an effective theory, which means that the theory loses its predictability at higher energies. Therefore, the Standard Model has to be extended in a proper way to describe physics at higher energies. A most promising concept for the extension of the SM is those of Supersymmetry, where for each particle of the SM one or more superpartner particles are introduced. The simplest and most attractive extension of the SM is called Minimal Supersymmetric Standard Model (MSSM). Minimal refers to the additional field content, which is kept as low as possible. In fact the MSSM consists of the fields of the SM and their corresponding supersymmetric partner fields, as well as one additional Higgs doublet. The presence of this additional Higgs doublet leads to the existence of five physical Higgs bosons in the MSSM. The search for supersymmetric particles and Higgs bosons is one of the primary goals of the Large Hadron Collider (LHC) at the CERN laboratory, producing collisions at sufficiently high energies to detect these particles. For the discovery of these new particles, precise pre- dictions of the corresponding decay widths and branching rations are utmost mandatory. To contribute with the precision of the LHC and the future ILC, Feynman amplitudes should be calculated at least to one-loop order. Since these calculations lead to so called UV- and IR- divergences, it is essential to perform a renormalization procedure, where the divergences are subtracted by a proper definition of counterterms. The goal of this work was to develop a program package, which calculates all MSSM two- body Higgs decay widths and corresponding branching ratios at full one

  9. MSSM Higgs boson searches at the LHC: benchmark scenarios after the discovery of a Higgs-like particle

    International Nuclear Information System (INIS)

    Carena, M.; Heinemeyer, S.; Staal, O.; Wagner, C.E.M.; Weiglein, G.

    2013-01-01

    A Higgs-like particle with a mass of about 125.5 GeV has been discovered at the LHC. Within the current experimental uncertainties, this new state is compatible with both the predictions for the Standard Model (SM) Higgs boson and with the Higgs sector in the Minimal Supersymmetric Standard Model (MSSM). We propose new low-energy MSSM benchmark scenarios that, over a wide parameter range, are compatible with the mass and production rates of the observed signal. These scenarios also exhibit interesting phenomenology for the MSSM Higgs sector. We propose a slightly updated version of the well-known m h max scenario, and a modified scenario (m h mod ), where the light CP-even Higgs boson can be interpreted as the LHC signal in large parts of the M A -tan β plane. Furthermore, we define a light stop scenario that leads to a suppression of the lightest CP-even Higgs gluon fusion rate, and a light stau scenario with an enhanced decay rate of h→γγ at large tan β. We also suggest a τ-phobic Higgs scenario in which the lightest Higgs can have suppressed couplings to down-type fermions. We propose to supplement the specified value of the μ parameter in some of these scenarios with additional values of both signs. This has a significant impact on the interpretation of searches for the non-SM-like MSSM Higgs bosons. We also discuss the sensitivity of the searches to heavy Higgs decays into light charginos and neutralinos, and to decays of the form H→hh. Finally, in addition to all the other scenarios where the lightest CP-even Higgs is interpreted as the LHC signal, we propose a low-M H scenario, where instead the heavy CP-even Higgs boson corresponds to the new state around 125.5 GeV. (orig.)

  10. Multiple nano elements of SCC--transition from phenomenology to predictive mechanistics

    International Nuclear Information System (INIS)

    Staehle, R.W.

    2009-01-01

    Full text of publication follows: Predicting the occurrence and rate of stress corrosion cracking in materials of construction is one of the most critical pathways for assuring the reliability of light water nuclear reactor plants. It is the general intention of operators of nuclear plants that they continue performing satisfactorily for times of 60 to 80 years at least. Such times are beyond existing experience, and there are no bases for choosing credible predictions. Present bases for predicting SCC rely on anecdotal experience for predicting what materials sustain SCC in specified environments and on phenomenological correlations using such parameters as K (stress intensity), 1/T (temperature), E(corr) (corrosion potential), pH, [x] a (concentration), other established quantities, and statistical correlations. While these phenomenological correlations have served the industry well in the past, they have also allowed grievous mistakes. Further, such correlations are flawed in their fundamental credibility. Predicting SCC in aqueous solutions means to predict its dependence upon the seven primary variables: potential, pH, species, alloy composition, alloy structure, stress and temperature. A serious prediction of SCC upon these seven primary variables can only be achieved by moving to fundamental nano elements. Unfortunately, useful predictability from the nano approach cannot be achieved quickly or easily; thus, it will continue to be necessary to rely on existing phenomenology. However, as the nano approach evolves, it can contribute increasingly to the quantitative capacity of the phenomenological approach. The nano approach will require quite different talents and thinking than are now applied to the prediction of SCC; while some of the boundary conditions of phenomenology must continue to be applied, elements of the nano approach will include accounting for at least, typically, the following multiple elements as they apply at the sites of initiation and at

  11. Improvement of bottom-quark associated Higgs-boson production predictions for LHC using HERA data

    Energy Technology Data Exchange (ETDEWEB)

    Andrii, Gizhko; Achim, Geiser [Deutsches Elektronen-Synchrotron, Hamburg (Germany)

    2016-07-01

    The dependence of the inclusive total cross section of the bottom-quark associated Higgs-boson production predictions at the LHC, pp → (b anti b)H+X on the treatment of the beauty quark mass is studied in the context of CMS measurements. For two different schemes (four flavour scheme (4FS) and five flavour scheme (5FS)) the theoretical uncertainty due to the beauty quark mass is estimated, and the potential improvement arising from a QCD analysis of HERA beauty data is demonstrated.

  12. Higgs Physics

    CERN Document Server

    Pomarol, Alex

    2016-01-01

    With the discovery of the Higgs, we have access to a plethora of new physical processes that allow us to further test the SM and beyond. We show a convenient way to parametrize these physics using an effective theory for Higgs couplings, discussing the importance of the basis selection, predictions from a SM effective field theory, and possible ways to measure these couplings with special attention to the high-energy regime. Predictions from the MSSM and MCHM, with the comparison with data, are also provided.

  13. Smoking-gun signatures for little Higgs models

    International Nuclear Information System (INIS)

    Han, Tao

    2004-01-01

    The little Higgs idea is a new way to solve the 'little hierarchy' problem by protecting the Higgs mass from quadratically divergent one-loop corrections. After a general introduction, I first describe the Littlest Higgs model to illustrate the little Higgs idea. I then present certain phenomenological signatures of two classes of little Higgs theories for future colliders. I emphasize to test the cancellation mechanism and how to distinguish different little Higgs models. (author)

  14. Prediction of the light CP-even Higgs-boson mass of the MSSM. Towards the ILC precision

    International Nuclear Information System (INIS)

    Hahn, T.; Hollik, W.; Rzehak, H.

    2014-04-01

    The signal discovered in the Higgs searches at the LHC can be interpreted as the Higgs boson of the Standard Model as well as the light CP-even Higgs boson of the Minimal Supersymmetric Standard Model (MSSM). In this context 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. This precision can be improved substantially below the level of ∝50 MeV at the future International Linear Collider (ILC). Within the MSSM the mass of the light CP-even Higgs boson, M h , can directly be predicted from the other parameters of the model. The accuracy of this prediction should match the one of the experimental measurements. The relatively high experimentally observed value of the mass of about 125.6 GeV has led to many investigations where the supersymmetric (SUSY) partners of the top quark have masses in the multi-TeV range. We review the recent improvements for the prediction for M h in the MSSM for large scalar top masses. They were obtained 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. However, substantial further improvements will be needed to reach the ILC precision. The newly obtained corrections to M h are included into the code FeynHiggs.

  15. Higgs Portal into Hidden Sectors

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Several attractive theoretical ideas suggest the existence of one or more 'hidden sectors' consisting of standard model singlet fields, some of which may not be too heavy. There is a profound reason to think that the Higgs sector might provide the first access to these hidden sectors. This scenario could affect Higgs phenomenology in drastic ways.

  16. Higgs mass prediction in the MSSM at three-loop level in a pure DR context

    Energy Technology Data Exchange (ETDEWEB)

    Harlander, Robert V.; Klappert, Jonas; Voigt, Alexander [RWTH Aachen University, Institute for Theoretical Particle Physics and Cosmology, Aachen (Germany)

    2017-12-15

    The impact of the three-loop effects of order α{sub t}α{sub s}{sup 2} on the mass of the light CP-even Higgs boson in the MSSM is studied in a pure DR context. For this purpose, we implement the results of Kant et al. (JHEP 08:104, 2010) into the C++ module Himalaya and link it to FlexibleSUSY, a Mathematica and C++ package to create spectrum generators for BSM models. The three-loop result is compared to the fixed-order two-loop calculations of the original FlexibleSUSY and of FeynHiggs, as well as to the result based on an EFT approach. Aside from the expected reduction of the renormalization scale dependence with respect to the lower-order results, we find that the three-loop contributions significantly reduce the difference from the EFT prediction in the TeV-region of the SUSY scale M{sub S}. Himalaya can be linked also to other two-loop DR codes, thus allowing for the elevation of these codes to the three-loop level. (orig.)

  17. CP violation in supersymmetry, Higgs sector and the large hadron ...

    Indian Academy of Sciences (India)

    I would then point out some interesting aspects of the phenomenology of a moderately light charged Higgs boson, consistent with the LEP constraints, in this scenario. Decay of such a charged Higgs boson would also allow a probe of a light (≲ 50 GeV), CP-violating (CPV) Higgs boson. Such a light neutral Higgs boson ...

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

    Science.gov (United States)

    Hahn, T; Heinemeyer, S; Hollik, W; Rzehak, H; Weiglein, G

    2014-04-11

    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.

  19. Precise prediction for the light MSSM Higgs-boson mass combining effective field theory and fixed-order calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, Henning; Hollik, Wolfgang [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Munich (Germany)

    2016-09-15

    In the Minimal Supersymmetric Standard Model heavy superparticles introduce large logarithms in the calculation of the lightest CP-even Higgs-boson mass. These logarithmic contributions can be resummed using effective field theory techniques. For light superparticles, however, fixed-order calculations are expected to be more accurate. To gain a precise prediction also for intermediate mass scales, the two approaches have to be combined. Here, we report on an improvement of this method in various steps: the inclusion of electroweak contributions, of separate electroweakino and gluino thresholds, as well as resummation at the NNLL level. These improvements can lead to significant numerical effects. In most cases, the lightest CP-even Higgs-boson mass is shifted downwards by about 1 GeV. This is mainly caused by higher-order corrections to the MS top-quark mass. We also describe the implementation of the new contributions in the code FeynHiggs. (orig.)

  20. Phenomenology of new physics beyond the Standard Model: signals of Supersymmetry with displaced vertices and an extended Higgs sector at colliders

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00334334

    2017-08-02

    Our current understanding of matter and its interactions is summarised in the Standard Model (SM) of particle physics. Many experiments have tested the predictions of the SM with great success, but others have brought our ignorance into focus by showing us there are new phenomena that we can not describe within the framework of the SM. These include the experimental observations of neutrino masses and dark matter, which confirms there must be new physics. What this new physics may look like at colliders motivates the original work in this thesis, which comprises three studies: the prospects of future electron-positron colliders in testing a model with an extended Higgs sector with a scalar triplet, doublet and singlet; the discovery potential at the Large Hadron Collider (LHC) of a non-minimal Supersymmetric model via conventional sparticle searches and via searches for displaced vertices; and the experimental search for long-lived massive particles via a displaced vertex signature using data of proton-proton...

  1. FN-2HDM: Two Higgs Doublet Models with Froggatt-Nielsen symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Dery, Avital; Nir, Yosef [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Herzl 234, Rehovot 76100 (Israel)

    2017-04-03

    We embed Two Higgs Doublet Models (2HDMs) in the Froggatt Nielsen (FN) framework. We find that the approximate FN symmetry predicts i) approximate Natural Flavor Conservation (NFC) of Types II or IV in the Yukawa sector, and ii) approximate Peccei-Quinn (PQ) symmetry in the scalar sector. We discuss the phenomenological consequences of these features.

  2. Higgs bosons and sleptons in an alternative left-right model

    International Nuclear Information System (INIS)

    Roszkowski, L.

    1990-01-01

    The phenomenological structure of the combined Higgs-boson--slepton sector of the alternative left-right-supersymmetric model introduced by Ma is explored. Constraints upon and relations between Higgs-boson and slepton masses are derived and a tightly constrained mass spectrum is found. In general, one neutral Higgs boson is never heavier than 98 GeV, one neutral Higgs boson is always nearly degenerate in mass with the extra neutral gauge boson Z 2 0 , and the charged Higgs boson can in principle be as light as 22 GeV. Further constraints require large ratios of Higgs vacuum expectation values, strongly favor the W R mass above ∼423 GeV, predict one Higgs-boson mass to be always very close to 98 GeV, and masses of the other Higgs bosons and the sleptons to be bounded from above and preferably not much above the Z mass. In addition, the possibility of detecting light Higgs bosons at CERN LEP and the SLAC Linear Collider is briefly discussed

  3. The universal Higgs fit

    DEFF Research Database (Denmark)

    Giardino, P. P.; Kannike, K.; Masina, I.

    2014-01-01

    We perform a state-of-the-art global fit to all Higgs data. We synthesise them into a 'universal' form, which allows to easily test any desired model. We apply the proposed methodology to extract from data the Higgs branching ratios, production cross sections, couplings and to analyse composite...... Higgs models, models with extra Higgs doublets, supersymmetry, extra particles in the loops, anomalous top couplings, and invisible Higgs decays into Dark Matter. Best fit regions lie around the Standard Model predictions and are well approximated by our 'universal' fit. Latest data exclude the dilaton...... as an alternative to the Higgs, and disfavour fits with negative Yukawa couplings. We derive for the first time the SM Higgs boson mass from the measured rates, rather than from the peak positions, obtaining M-h = 124.4 +/- 1.6 GeV....

  4. Evaluation of the Predictive Capabilities of a Phenomenological Combustion Model for Natural Gas SI Engine

    Directory of Open Access Journals (Sweden)

    Toman Rastislav

    2017-12-01

    Full Text Available The current study evaluates the predictive capabilities of a new phenomenological combustion model, available as a part of the GT-Suite software package. It is comprised of two main sub-models: 0D model of in-cylinder flow and turbulence, and turbulent SI combustion model. The 0D in-cylinder flow model (EngCylFlow uses a combined K-k-ε kinetic energy cascade approach to predict the evolution of the in-cylinder charge motion and turbulence, where K and k are the mean and turbulent kinetic energies, and ε is the turbulent dissipation rate. The subsequent turbulent combustion model (EngCylCombSITurb gives the in-cylinder burn rate; based on the calculation of flame speeds and flame kernel development. This phenomenological approach reduces significantly the overall computational effort compared to the 3D-CFD, thus allowing the computation of full engine operating map and the vehicle driving cycles. Model was calibrated using a full map measurement from a turbocharged natural gas SI engine, with swirl intake ports. Sensitivity studies on different calibration methods, and laminar flame speed sub-models were conducted. Validation process for both the calibration and sensitivity studies was concerning the in-cylinder pressure traces and burn rates for several engine operation points achieving good overall results.

  5. QCD analysis of light charged Higgs production through polarized top quark decay in two different frames

    Energy Technology Data Exchange (ETDEWEB)

    Nejad, S. Mohammad Moosavi [Faculty of Physics, Yazd University,P.O. Box 89195-741, Yazd (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Abbaspour, S. [Faculty of Physics, Yazd University,P.O. Box 89195-741, Yazd (Iran, Islamic Republic of)

    2017-03-09

    Light and heavy charged Higgs bosons are predicted by many models with an extended Higgs sector such as the two-Higgs-doublet model (2HDM). Searches for the charged Higgs bosons have been done by the ATLAS and the CMS experiments at the Large Hadron Collider (LHC) in proton-proton collision. However, a definitive search of charged Higgs bosons still has to be carried out by the LHC experiments. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work we study the O(α{sub s}) correction to the energy spectrum of the inclusive bottom-flavored mesons (X{sub b}) in polarized top quark decays into a light charged Higgs boson (m{sub H{sup +}}Higgs bosons. To present our phenomenological predictions, we restrict ourselves to the constraints on the m{sub H{sup +}}−tan β parameter space determined by the recent results of the CMS and the ATLAS collaborations.

  6. Higgs portal inflation

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Oleg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lee, Hyun Min [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2011-05-15

    The Higgs sector of the Standard Model offers a unique opportunity to probe the hidden sector. The Higgs squared operator is the only dimension two operator which is Lorentz and gauge invariant. It can therefore couple both to scalar curvature and the hidden sector at the dim-4 level. We consider the possibility that a combination of the Higgs and a singlet from the hidden sector plays the role of inflaton, due to their large couplings to gravity. This implies that the quartic couplings satisfy certain constraints which leads to distinct low energy phenomenology, including Higgs signals at the LHC. We also address the unitarity issues and show that our analysis survives the unitarization procedure. (orig.)

  7. Partially composite Higgs models

    DEFF Research Database (Denmark)

    Alanne, Tommi; Buarque Franzosi, Diogo; Frandsen, Mads T.

    2018-01-01

    We study the phenomenology of partially composite-Higgs models where electroweak symmetry breaking is dynamically induced, and the Higgs is a mixture of a composite and an elementary state. The models considered have explicit realizations in terms of gauge-Yukawa theories with new strongly...... interacting fermions coupled to elementary scalars and allow for a very SM-like Higgs state. We study constraints on their parameter spaces from vacuum stability and perturbativity as well as from LHC results and find that requiring vacuum stability up to the compositeness scale already imposes relevant...... constraints. A small part of parameter space around the classically conformal limit is stable up to the Planck scale. This is however already strongly disfavored by LHC results. in different limits, the models realize both (partially) composite-Higgs and (bosonic) technicolor models and a dynamical extension...

  8. Higgs Portal Inflation

    CERN Document Server

    Lebedev, Oleg

    2011-01-01

    The Higgs sector of the Standard Model offers a unique opportunity to probe the hidden sector. The Higgs squared operator is the only dimension two operator which is Lorentz and gauge invariant. It can therefore couple both to scalar curvature and the hidden sector at the dim--4 level. We consider the possibility that a combination of the Higgs and a singlet from the hidden sector plays the role of inflaton, due to their large couplings to gravity. This implies that the quartic couplings satisfy certain constraints which leads to distinct low energy phenomenology, including Higgs signals at the LHC. We also address the unitarity issues and show that our analysis survives the unitarization procedure.

  9. Thought insertion as a self-disturbance: An integration of predictive coding and phenomenological approaches

    Directory of Open Access Journals (Sweden)

    Philipp Sterzer

    2016-10-01

    Full Text Available Current theories in the framework of hierarchical predictive coding propose that positive symptoms of schizophrenia, such as delusions and hallucinations, arise from an alteration in Bayesian inference, the term inference referring to a process by which learned predictions are used to infer probable causes of sensory data. However, for one particularly striking and frequent symptom of schizophrenia, thought insertion, no plausible account has been proposed in terms of the predictive-coding framework. Here we propose that thought insertion is due to an altered experience of thoughts as coming from nowhere, as is already indicated by the early 20th century phenomenological accounts by the early Heidelberg School of psychiatry. These accounts identified thought insertion as one of the self-disturbances (from German: Ichstörungen of schizophrenia and used mescaline as a model-psychosis in healthy individuals to explore the possible mechanisms. The early Heidelberg School (Gruhle, Mayer-Gross, Beringer first named and defined the self-disturbances, and proposed that thought insertion involves a disruption of the inner connectedness of thoughts and experiences, and a becoming sensory of those thoughts experienced as inserted. This account offers a novel way to integrate the phenomenology of thought insertion with the predictive coding framework. We argue that the altered experience of thoughts may be caused by a reduced precision of context-dependent predictions, relative to sensory precision. According to the principles of Bayesian inference, this reduced precision leads to increased prediction-error signals evoked by the neural activity that encodes thoughts. Thus, in analogy with the prediction-error related aberrant salience of external events that has been proposed previously, internal events such as thoughts (including volitions, emotions and memories can also be associated with increased prediction-error signaling and are thus imbued with

  10. Heavy Higgs searches. Flavour matters

    International Nuclear Information System (INIS)

    Gori, Stefania; Paul, Ayan

    2017-10-01

    We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.

  11. Heavy Higgs searches. Flavour matters

    Energy Technology Data Exchange (ETDEWEB)

    Gori, Stefania [Cincinnati Univ., OH (United States). Dept. of Physics; Grojean, Christophe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Juste, Aurelio [Institut de Fisica d' Altes Energies (IFAE), Barcelona (Spain); Institucio Catalanade Recerca i Estudis Avancats (ICREA), Barcelona (Spain); Paul, Ayan [INFN, Sezione di Roma (Italy)

    2017-10-15

    We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.

  12. Reproducing the Higgs boson data with vector-like quarks

    International Nuclear Information System (INIS)

    Bonne, N.; Moreau, G.

    2012-01-01

    Vector-Like (VL) quarks arise in the main alternatives to the supersymmetric extensions of the Standard Model (SM). Given the experimental possibility of a 125 GeV Higgs boson with rates significantly different from the SM expectations, it is motivating to study the effects of VL quarks on the Higgs boson cross sections and branching ratios. We perform a systematic search for the minimal field contents and gauge group representations of VL quarks able to significantly improve the fit of the measured Higgs rates, and simultaneously, to satisfy the direct constraints on VL quark masses as well as the electro-weak precision tests. In particular, large enhancements can be achieved in certain diphoton channels - as pointed out by both the ATLAS and CMS Collaborations - optimizing then the Higgs rate fit. This is a consequence of the introduction of VL quarks, with high electric charges of 8/3 or -7/3, which are exchanged in the Higgs-to-diphoton loop. Interestingly, the field contents and formal Higgs couplings obtained here are similar to those of scenarios in warped/composite frameworks arising from different motivations. The various exotic-charge quarks predicted, possibly below the TeV scale, might lead to a rich phenomenology soon at the LHC.

  13. Higgs production at NNLO in QCD. The VBF channel

    International Nuclear Information System (INIS)

    Bolzoni, P.; Moch, S.; Zaro, M.; Maltoni, F.

    2010-06-01

    We present a phenomenological study for the production of the Higgs boson at next-to-next-to-leading order (NNLO) in QCD via the vector boson fusion (VBF) process. After a general discussion about the different production channels of the Higgs, we show results for hadron colliders like LHC and Tevatron in VBF. The theoretical predictions are obtained using the structure function approach. This approximation turns out to be more accurate than the precision to which the VBF Higgs production channel can be considered a well defined process by itself and the theoretical uncertainty which are of the order of 1-2%. The uncertainties due to parton distributions are also discussed and are estimated to be at the same level. (orig.)

  14. Where Is Higgs Boson?

    CERN Multimedia

    2008-01-01

    Quantum physicists think they know the answer. Probabilistic calculations reveal than the data provided by previous experiments has been miscalculated and that the Higgs boson has in fact been discovered. Weird! The Higgs boson is the only particle predicted by the Standard Model that hasn't been discovered yet.

  15. Vector and axial-vector resonances in composite models of the Higgs boson

    Energy Technology Data Exchange (ETDEWEB)

    Franzosi, Diogo Buarque [II. Physikalisches Institut, Universität Göttingen,Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Cacciapaglia, Giacomo; Cai, Haiying; Deandrea, Aldo [Univ Lyon, Université Lyon 1, CNRS/IN2P3, IPNL,F-69622, Villeurbanne (France); Frandsen, Mads [CP-Origins & Danish Institute for Advanced Study DIAS, University of Southern Denmark,Campusvej 55, DK-5230 Odense M (Denmark)

    2016-11-11

    We provide a non-linear realisation of composite Higgs models in the context of the SU(4)/Sp(4) symmetry breaking pattern, where the effective Lagrangian of the spin-0 and spin-1 resonances is constructed via the CCWZ prescription using the Hidden Symmetry formalism. We investigate the EWPT constraints by accounting the effects from reduced Higgs couplings and integrating out heavy spin-1 resonances. This theory emerges from an underlying theory of gauge interactions with fermions, thus first principle lattice results predict the massive spectrum in composite Higgs models. This model can be used as a template for the phenomenology of composite Higgs models at the LHC and at future 100 TeV colliders, as well as for other application. In this work, we focus on the formalism for spin-1 resonances and their bounds from di-lepton and di-boson searches at the LHC.

  16. Strong moduli stabilization and phenomenology

    CERN Document Server

    Dudas, Emilian; Mambrini, Yann; Mustafayev, Azar; Olive, Keith A

    2013-01-01

    We describe the resulting phenomenology of string theory/supergravity models with strong moduli stabilization. The KL model with F-term uplifting, is one such example. Models of this type predict universal scalar masses equal to the gravitino mass. In contrast, A-terms receive highly suppressed gravity mediated contributions. Under certain conditions, the same conclusion is valid for gaugino masses, which like A-terms, are then determined by anomalies. In such models, we are forced to relatively large gravitino masses (30-1000 TeV). We compute the low energy spectrum as a function of m_{3/2}. We see that the Higgs masses naturally takes values between 125-130 GeV. The lower limit is obtained from the requirement of chargino masses greater than 104 GeV, while the upper limit is determined by the relic density of dark matter (wino-like).

  17. MSSM Higgs boson searches at the LHC. Benchmark scenarios after the discovery of a Higgs-like particle

    Energy Technology Data Exchange (ETDEWEB)

    Carena, M. [Fermilab, Batavia, IL (United States). Theoretical Physics Dept.; Chicago Univ., IL (United States). Enrico Fermi Inst.; Chicago Univ., IL (United States). Kavli Inst. for Cosmological Physics; Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, O. [Stockholm Univ. (Sweden). Dept. of Physics; Wagner, C.E.M. [Chicago Univ., IL (United States). Enrico Fermi Inst.; Chicago Univ., IL (United States). Kavli Inst. for Cosmological Physics; Argonne National Laboratory, Argonne, IL (United States). HEP Division; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-02-15

    A Higgs-like particle with a mass of about 125.5 GeV has been discovered at the LHC. Within the current experimental uncertainties, this new state is compatible with both the predictions for the Standard Model (SM) Higgs boson and with the Higgs sector in the Minimal Supersymmetric Standard Model (MSSM). We propose new low- energy MSSM benchmark scenarios that, over a wide parameter range, are compatible with the mass and production rates of the observed signal. These scenarios also exhibit interesting phenomenology for the MSSM Higgs sector. We propose a slightly updated version of the well-known m{sup max}{sub h} scenario, and a modified scenario (m{sup mod}{sub h}), where the light CP-even Higgs boson can be interpreted as the LHC signal in large parts of the M{sub A}-tan {beta} plane. Furthermore, we define a light stop scenario that leads to a suppression of the lightest CP-even Higgs gluon fusion rate, and a light stau scenario with an enhanced decay rate of h{yields}{gamma}{gamma} at large tan {beta}. We also suggest a {tau}-phobic Higgs scenario in which the lightest Higgs can have suppressed couplings to down-type fermions. We propose to supplement the specified value of the {mu} parameter in some of these scenarios with additional values of both signs. This has a significant impact on the interpretation of searches for the non SM-like MSSM Higgs bosons. We also discuss the sensitivity of the searches to heavy Higgs decays into light charginos and neutralinos, and to decays of the form H{yields}{gamma}{gamma}. Finally, in addition to all the other scenarios where the lightest CP-even Higgs is interpreted as the LHC signal, we propose a low-M{sub H} scenario, where instead the heavy CP-even Higgs boson corresponds to the new state around 125.5 GeV.

  18. arXiv The Hyperbolic Higgs

    CERN Document Server

    Cohen, Timothy; Giudice, Gian F.; Mccullough, Matthew

    2018-05-15

    We introduce the Hyperbolic Higgs, a novel solution to the little hierarchy problem that features Standard Model neutral scalar top partners. At one-loop order, the protection from ultraviolet sensitivity is due to an accidental non-compact symmetry of the Higgs potential that emerges in the infrared. Once the general features of the effective description are detailed, a completion that relies on a five dimensional supersymmetric framework is provided. Novel phenomenology is compared and contrasted with the Twin Higgs scenario.

  19. Baryogenesis via Elementary Goldstone Higgs Relaxation

    DEFF Research Database (Denmark)

    Gertov, Helene; Pearce, Lauren; Sannino, Francesco

    2016-01-01

    We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....

  20. Finite Unified Theories and the Higgs boson

    CERN Document Server

    Heinemeyer, Sven; Zoupanos, George

    2012-01-01

    All-loop Finite Unified Theories (FUTs) are very interesting N = 1 supersymmetric Grand Unified Theories (GUTs) realising an old field theory dream, and moreover have a remarkable predictive power due to the required reduction of couplings. Based on this theoretical framework phenomenologically consistent FUTs have been constructed. Here we review two FUT models based on the SU(5) gauge group, which can be seen as special, restricted and thus very predictive versions of the MSSM. We show that from the requirement of correct prediction of quark masses and other experimental constraints a light Higgs-boson mass in the range M_h ~ 121 - 126 GeV is predicted, in striking agreement with recent experimental results from ATLAS and CMS. The model furthermore naturally predicts a relatively heavy spectrum with colored supersymmetric particles above ~ 1.5 TeV in agreement with the non-observation of those particles at the LHC.

  1. The HiggsTools handbook: a beginners guide to decoding the Higgs sector

    Science.gov (United States)

    Boggia, M.; Cruz-Martinez, J. M.; Frellesvig, H.; Glover, N.; Gomez-Ambrosio, R.; Gonella, G.; Haddad, Y.; Ilnicka, A.; Jones, S.; Kassabov, Z.; Krauss, F.; Megy, T.; Melini, D.; Napoletano, D.; Passarino, G.; Patel, S.; Rodriguez-Vazquez, M.; Wolf, T.

    2018-06-01

    This report summarises some of the activities of the HiggsTools initial training network working group in the period 2015–2017. The main goal of this working group was to produce a document discussing various aspects of state-of-the-art Higgs physics at the large hadron collider (LHC) in a pedagogic manner. The first part of the report is devoted to a description of phenomenological searches for new physics (NP) at the LHC. All of the available studies of the couplings of the new resonance discovered in 2012 by the ATLAS and CMS experiments (Aad et al (ATLAS Collaboration) 2012 Phys. Lett. B 716 1–29 Chatrchyan et al (CMS Collaboration) 2012 Phys. Lett. B 716 30–61) conclude that it is compatible with the Higgs boson of the standard model (SM) within present precision. So far the LHC experiments have given no direct evidence for any physical phenomena that cannot be described by the SM. As the experimental measurements become more and more precise, there is a pressing need for a consistent framework in which deviations from the SM predictions can be computed precisely. Such a framework should be applicable to measurements in all sectors of particle physics, not only LHC Higgs measurements but also electroweak precision data, etc. We critically review the use of the κ-framework, fiducial and simplified template cross sections, effective field theories, pseudoobservables and phenomenological Lagrangians. Some of the concepts presented here are well known and were used already at the time of the large electron–positron collider (LEP) experiment. However, after years of theoretical and experimental development, these techniques have been refined, and we describe new tools that have been introduced in order to improve the comparison between theory and experimental data. In the second part of the report, we propose {φ }η * as a new and complementary observable for studying Higgs boson production at large transverse momentum in the case where the Higgs boson

  2. Higgs Inflation as a Mirage

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    After reviewing the nice properties of Higgs inflation and some of its problems, I will discuss a simple unitarization of the scenario that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Inflationary dynamics is not dominated by the Higgs field, but 'Higgs inflation' arises as an approximate 'mirage' picture of the true dynamics. I will speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.

  3. Precise predictions for Higgs production in association with a W-boson pair at ILC

    International Nuclear Information System (INIS)

    Mao, Song; Wen-Gan, Ma; Ren-You, Zhang; Lei, Guo; Shao-Ming, Wang

    2009-01-01

    Higgs-boson production in association with a W-boson pair at e + e - linear colliders is one of the important processes in probing the coupling between the Higgs boson and vector gauge bosons and discovering the signature of new physics. We describe the impact of the complete electroweak (EW) radiative corrections of O(α ew ) to this process in the standard model (SM) at the International Linear Collider (ILC), and investigate the dependence of the lowest-order (LO) and EW next-to-leading order (NLO) corrected cross sections on the colliding energy √(s) and the Higgs-boson mass. The LO and NLO EW corrected distributions of the invariant mass of the W-boson pair and the transverse momenta of the final W-boson and Higgs boson are presented. Our numerical results show that the relative EW radiative correction (δ ew ) varies from -19.4% to 0.2% when m H =120 GeV and √(s) grows from 300 GeV to 1.2 TeV. (orig.)

  4. Phenomenological aspects of unified theories

    International Nuclear Information System (INIS)

    Peccei, R.D.

    1987-01-01

    The author briefly discusses two new phenomena of recent interest, the 5/sup th/ force and variant axions. The former, for its elucidation, will require further gravitational experiments, but the author concludes that variant axions are now definitely rules out experimentally. Various aspects of superstring phenomenology are then addressed, including some of the generic predictions of superstrings and some of its generic problems. In particular, he discusses some of the phenomenological consequences of having an extra Z 0 boson and the circumstances under which this excitation is a genuine prediction of superstrings. Since it is likely that a more reliable relic of superstrings will be provided by the presence of superpartners at low energy (≤ TeV), he discusses some of the bounds for squarks and gluinos obtained at the SppS collider and the expectations for their production at the Tevatron. As a final topic, he touches upon some of the consequences that result from having the Fermi scale arise from an underlying theory. Some aspects of the composite Higgs model and of the strongly coupled standard model are briefly reviewed

  5. Higgs boson production in association with a jet at next-to-next-to-leading order

    CERN Document Server

    Boughezal, Radja; Melnikov, Kirill; Petriello, Frank; Schulze, Markus

    2015-01-01

    We present precise predictions for Higgs boson production in association with a jet. Our calculation is accurate to next-to-next-to-leading order (NNLO) QCD in the Higgs Effective Field Theory and constitutes the first complete NNLO computation for Higgs production with a final-state jet in hadronic collisions. We include all relevant phenomenological channels and present fully-differential results as well as total cross sections for the LHC. Our NNLO predictions reduce the unphysical scale dependence by more than a factor of two and enhance the total rate by about twenty percent compared to NLO QCD predictions. Our results demonstrate for the first time satisfactory convergence of the perturbative series.

  6. Quantum effects on Higgs-boson production and decay due to Majorana neutrinos

    International Nuclear Information System (INIS)

    Kniehl, B.A.

    1994-02-01

    We analyze the phenomenological implications for new electroweak physics in the Higgs sector in the framework of SU(2) L x U(1) Y theories that naturally predict heavy Majorana neutrinos. We calculate the one-loop Majorana-neutrino contributions to the decay rates of the Higgs boson into pairs of quarks and intermediate bosons and to its production cross section via bremsstrahlung in e + e - collisions. It turns out that these are extremely small in three-generation models. On the other hand, the sizeable quantum corrections generated by a conventional fourth generation with a Dirac neutrino may be screened considerably in the presence of a Majorana degree of freedom. (orig.)

  7. HiggsSignals. Confronting arbitrary Higgs sectors with measurements at the Tevatron and the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). The Oskar Klein Centre; Stefaniak, Tim [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-05-15

    HiggsSignals is a Fortran90 computer code that allows to test the compatibility of Higgs sector predictions against Higgs rates and masses measured at the LHC or the Tevatron. Arbitrary models with any number of Higgs bosons can be investigated using a model-independent input scheme based on HiggsBounds. The test is based on the calculation of a {chi}{sup 2} measure from the predictions and the measured Higgs rates and masses, with the ability of fully taking into account systematics and correlations for the signal rate predictions, luminosity and Higgs mass predictions. It features two complementary methods for the test. First, the peak-centered method, in which each observable is defined by a Higgs signal rate measured at a specific hypothetical Higgs mass, corresponding to a tentative Higgs signal. Second, the mass-centered method, where the test is evaluated by comparing the signal rate measurement to the theory prediction at the Higgs mass predicted by the model. The program allows for the simultaneous use of both methods, which is useful in testing models with multiple Higgs bosons. The code automatically combines the signal rates of multiple Higgs bosons if their signals cannot be resolved by the experimental analysis. We compare results obtained with HiggsSignals to official ATLAS and CMS results for various examples of Higgs property determinations and find very good agreement. A few examples of HiggsSignals applications are provided, going beyond the scenarios investigated by the LHC collaborations. For models with more than one Higgs boson we recommend to use HiggsSignals and HiggsBounds in parallel to exploit the full constraining power of Higgs search exclusion limits and the measurements of the signal seen at m{sub H} {approx} 125.5 GeV.

  8. A not so little Higgs?

    International Nuclear Information System (INIS)

    Sutherland, D.G.

    2005-01-01

    Most recent models assuming the Higgs boson is a pseudo-Nambu-Goldstone boson (pNGb) are motivated by the indication from Standard Model fits that its mass is = SU(3) model we use is briefly discussed. Some potential theoretical and phenomenological problems are mentioned briefly

  9. The 4D Composite Higgs

    CERN Document Server

    De Curtis, Stefania; Tesi, Andrea

    2012-01-01

    We propose a four dimensional description of Composite Higgs Models which represents a complete framework for the physics of the Higgs as a pseudo-Nambu-Goldstone boson. Our setup captures all the relevant features of 5D models and more in general of composite Higgs models with partial compositeness. We focus on the minimal scenario where we include a single multiplet of resonances of the composite sector, as these will be the only degrees of freedom which might be accessible at the LHC. This turns out to be sufficient to compute the effective potential and derive phenomenological consequences of the theory. Moreover our simplified approach is well adapted to simulate these models at the LHC. We also consider the impact of non-minimal terms in the effective lagrangian which do not descend from a 5D theory and could be of phenomenological relevance, for example contributing to the S-parameter.

  10. Spin-one top partner: phenomenology

    Science.gov (United States)

    Collins, Jack H.; Jain, Bithika; Perelstein, Maxim; Lorier, Nicolas Rey-Le

    2014-08-01

    Cai, Cheng, and Terning (CCT) suggested a model in which the left-handed top quark is identified with a gaugino of an extended gauge group, and its superpartner is a spin-1 particle. We perform a phenomenological analysis of this model, with a focus on the spin-1 top partner, which we dub the "swan". We find that precision electroweak fits, together with direct searches for Z ' bosons at the LHC, place a lower bound of at least about 4.5 TeV on the swan mass. An even stronger bound, 10 TeV or above, applies in most of the parameter space, mainly due to the fact that the swan is typically predicted to be significantly heavier than the Z '. We find that the 125 GeV Higgs can be easily accommodated in this model with non-decoupling D-terms. In spite of the strong lower bound on the swan mass, we find that corrections to Higgs couplings to photons and gluons induced by swan loops are potentially observable at future Higgs factories. We also briefly discuss the prospects for discovering a swan at the proposed 100 TeV pp collider.

  11. Phenomenology of 2HDM with vectorlike quarks

    Science.gov (United States)

    Arhrib, A.; Benbrik, R.; King, S. J. D.; Manaut, B.; Moretti, S.; Un, C. S.

    2018-05-01

    In this paper, we examine the consistency of the Large Hadron Collider (LHC) data collected during Runs 1 and 2 by the ATLAS and CMS experiments with the predictions of a 2-Higgs doublet model embedding vectorlike quarks (VLQs) for p p →H , A production and H , A →γ γ decay mechanisms, respectively, of (nearly) degenerate C P -even (H ) and C P -odd (A ) Higgs bosons. We show that a scenario containing one single VLQ with electromagnetic charge 2 /3 can explain the above ATLAS and CMS data for masses in the region 350 GeV ≤mVLQ≤1.5 TeV or so, depending on tan β , and for several values of the mixing angle between the top quark (t ) and its VLQ counterpart (T ). We then perform a global fit onto the model by including all relevant experimental as well as theoretical constraints. The surviving samples of our analysis are discussed within 2 σ of the LHC measurements. Additionally, we also comment on the recent anomalous result reported by CMS using Run 2 data on the associated Standard Model Higgs boson production with top quark pairs p p →t t ¯ h with an observed significance of 3.3 σ . Other than these specific examples, we also present a phenomenological analysis of the main features of the model, including the most promising T decay channels.

  12. Higgs mass prediction in the MSSM at three-loop level in a pure \\overline{{ {DR}}} context

    Science.gov (United States)

    Harlander, Robert V.; Klappert, Jonas; Voigt, Alexander

    2017-12-01

    The impact of the three-loop effects of order α _tα _s^2 on the mass of the light CP-even Higgs boson in the { {MSSM}} is studied in a pure \\overline{{ {DR}}} context. For this purpose, we implement the results of Kant et al. (JHEP 08:104, 2010) into the C++ module Himalaya and link it to FlexibleSUSY, a Mathematica and C++ package to create spectrum generators for BSM models. The three-loop result is compared to the fixed-order two-loop calculations of the original FlexibleSUSY and of FeynHiggs, as well as to the result based on an EFT approach. Aside from the expected reduction of the renormalization scale dependence with respect to the lower-order results, we find that the three-loop contributions significantly reduce the difference from the EFT prediction in the TeV-region of the { {SUSY}} scale {M_S}. Himalaya can be linked also to other two-loop \\overline{{ {DR}}} codes, thus allowing for the elevation of these codes to the three-loop level.

  13. Phenomenology of a left-right-symmetric model inspired by the trinification model

    Energy Technology Data Exchange (ETDEWEB)

    Hetzel, Jamil

    2015-02-04

    The trinification model is an interesting extension of the Standard Model based on the gauge group SU(3){sub C} x SU(3){sub L} x SU(3){sub R}. It naturally explains parity violation as a result of spontaneous symmetry breaking, and the observed fermion masses and mixings can be reproduced using only a few parameters. We study the low-energy phenomenology of the trinification model in order to compare its predictions to experiment. To this end, we construct a low-energy effective field theory, thereby reducing the number of particles and free parameters that need to be studied. We constrain the model parameters using limits from new-particle searches as well as precision measurements. The scalar sector of the model allows for various phenomenological scenarios, such as the presence of a light fermiophobic scalar in addition to a Standard-Model-like Higgs, or a degenerate (twin) Higgs state at 126 GeV. We show how a measurement of the Higgs couplings can be used to distinguish such scenarios from the Standard Model. We find that the trinification model predicts that several new scalar particles have masses in the O(100 GeV) range. Moreover, large regions of the parameter space lead to measurable deviations from Standard-Model predictions of the Higgs couplings. Hence the trinification model awaits crucial tests at the Large Hadron Collider in the coming years.

  14. Collider signatures of flavorful Higgs bosons

    International Nuclear Information System (INIS)

    Altmannshofer, Wolfgang; Eby, Joshua; Gori, Stefania; Lotito, Matteo

    2016-01-01

    Motivated by our limited knowledge of the Higgs couplings to the first two generation fermions, we analyze the collider phenomenology of a class of two Higgs doublet models (2HDMs) with a nonstandard Yukawa sector. One Higgs doublet is mainly responsible for the masses of the weak gauge bosons and the third-generation fermions, while the second Higgs doublet provides mass for the lighter fermion generations. The characteristic collider signatures of this setup differ significantly from well-studied 2HDMs with natural flavor conservation, flavor alignment, or minimal flavor violation. New production mechanisms for the heavy scalar, pseudoscalar, and charged Higgs involving second-generation quarks can become dominant. The most interesting decay modes include H/A → cc,tc,μμ,τμ and H"± → cb,cs,μν. As a result, searches for low-mass dimuon resonances are currently among the best probes of the heavy Higgs bosons in this setup.

  15. A Historical Profile of the Higgs Boson

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John; Gaillard, Mary K.; Nanopoulos, Dimitri V.

    2012-01-31

    The Higgs boson was postulated in 1964, and phenomenological studies of its possible production and decays started in the early 1970s, followed by studies of its possible productionin e{sup +} e{sup -}, {anti p}p and pp collisions, in particular. Until recently, the most sensitive searches for the Higgs boson were at LEP between 1989 and 2000, which have been complemented bysearches at the Fermilab Tevatron. The LHC has recently entered the hunt, excluding a Higgs boson over a large range of masses and revealing a tantalizing hint in the range 119 to125 GeV, and there are good prospects that the existence or otherwise of the Higgs boson will soon be established. One of the most attractive possibilities is that the Higgs bosonis accompanied by supersymmetry, though composite options have yet to be excluded. This article reviews some of the key historical developments in Higgs physics over the past half-century.

  16. Origin and phenomenology of weak-doublet spin-1 bosons

    International Nuclear Information System (INIS)

    Chizhov, M.V.; Dvali, Gia

    2011-01-01

    We study phenomenological consequences of the Standard Model extension by the new spin-1 fields with the internal quantum numbers of the electroweak Higgs doublets. We show, that there are at least three different classes of theories, all motivated by the hierarchy problem, which predict appearance of such vector weak-doublets not far from the weak scale. The common feature for all the models is the existence of an SU(3) W gauge extension of the weak SU(2) W group, which is broken down to the latter at some energy scale around TeV. The Higgs doublet then emerges as either a pseudo-Nambu-Goldstone boson of a global remnant of SU(3) W , or as a symmetry partner of the true eaten-up Goldstone boson. In the third class, the Higgs is a scalar component of a high-dimensional SU(3) W gauge field. The common phenomenological feature of these theories is the existence of the electroweak doublet vectors (Z * ,W * ), which in contrast to well-known Z ' and W ' bosons posses only anomalous (magnetic moment type) couplings with ordinary light fermions. This fact leads to some unique signatures for their detection at the hadron colliders.

  17. Neutralino-stop co-annihilation into electroweak gauge and Higgs bosons at one loop

    Energy Technology Data Exchange (ETDEWEB)

    Harz, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Herrmann, B. [Univ. Savoie/CNRS, Annecy-le-Vieux (France). LAPTh; Klasen, M. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Kovarik, K. [Karlsruhe Institute of Technology, Karlsruhe (Germany). Inst. for Theoretical Physics; Le Boulc' h, Q. [Grenoble Univ. (France). CNRS-IN2P3/INPG

    2012-12-15

    We compute the full O({alpha}{sub s}) supersymmetric QCD corrections for neutralino-stop co-annihilation into electroweak gauge and Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). We show that these annihilation channels are phenomenologically relevant within the so-called phenomenological MSSM, in particular in the light of the observation of a Higgs-like particle with a mass of about 126 GeV at the LHC. We present in detail our calculation, including the renormalization scheme, the infrared treatment, and the kinematical subtleties to be addressed. Numerical results for the co-annihilation cross sections and the predicted neutralino relic density are presented. We demonstrate that the impact of including the corrections on the cosmologically preferred region of parameter space is larger than the current experimental uncertainty from WMAP data.

  18. Higgs inflation as a mirage

    Energy Technology Data Exchange (ETDEWEB)

    Barbón, J.L.F.; Casas, J.A. [IFT-UAM/CSIC, Universidad Autónoma de Madrid,C/Nicolás Cabrera 13, 28049 Madrid (Spain); Elias-Miró, J. [Departament de Física/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain); Espinosa, J.R. [ICREA/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain)

    2015-09-04

    We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.

  19. Higgs inflation as a mirage

    International Nuclear Information System (INIS)

    Barbón, J.L.F.; Casas, J.A.; Elias-Miró, J.; Espinosa, J.R.

    2015-01-01

    We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.

  20. Higgs physics at the Large Hadron Collider

    Indian Academy of Sciences (India)

    Higgs boson; Large Hadron Collider; electroweak symmetry; spin and CP of the Higgs boson ... I shall then give a short description of the pre-LHC constraints on the Higgs mass and the theoretical predictions for the LHC along with a discussion of the current experimental results, ending with prospects in the near future at ...

  1. Higgs mass prediction with non-universal soft supersymmetry breaking in MSSM

    International Nuclear Information System (INIS)

    Codoban, S.; Jurcisin, M.; Kazakov, D.

    2001-01-01

    In the framework of the MSSM (Minimal supersymmetric extension of the standard model) the non-universal boundary conditions of soft SUSY breaking parameters are considered. Taking as input the top, bottom and Z-boson masses, the values of the gauge couplings at the EW scale and the infrared quasi-fixed points for Yukawa couplings and the soft parameters the mass of the lightest CP-even Higgs boson is found to be m h = 92.7 -4.9 +10 ± 5 ± 0.4 GeV/c 2 for the low tan(β) case and m h 125.7 -9.0 +6.4 ± 5 ± 0.4 GeV/c 2 (μ > 0) or m h 125.4 -9.0 +6.6 ± 5 ± 0.4 Ge V/c 2 (μ < 0) in the case of large tan(β). (authors)

  2. The Higgs and Supersymmetry at Run II of the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Shih, David [Rutgers Univ., Piscataway, NJ (United States)

    2016-04-14

    Prof. David Shih was supported by DOE grant DE-SC0013678 from April 2015 to April 2016. His research during this year focused on the phenomenology of super-symmetry (SUSY) and maximizing its future discovery potential at Run II of the LHC. SUSY is one of the most well-motivated frameworks for physics beyond the Standard Model. It solves the "naturalness" or "hierarchy" problem by stabilizing the Higgs mass against otherwise uncontrolled quantum corrections, predicts "grand unification" of the fundamental forces, and provides many potential candidates for dark matter. However, after decades of null results from direct and indirect searches, the viable parameter space for SUSY is increasingly constrained. Also, the discovery of a Standard Model-like Higgs with a mass at 125 GeV places a stringent constraint on SUSY models. In the work supported on this grant, Shih has worked on four different projects motivated by these issues. He has built natural SUSY models that explain the Higgs mass and provide viable dark matter; he has studied the parameter space of "gauge mediated supersymmetry breaking" (GMSB) that satisfies the Higgs mass constraint; he has developed new tools for the precision calculation of flavor and CP observables in general SUSY models; and he has studied new techniques for discovery of supersymmetric partners of the top quark.

  3. The Higgs and Supersymmetry at Run II of the LHC

    International Nuclear Information System (INIS)

    Shih, David

    2016-01-01

    Prof. David Shih was supported by DOE grant DE-SC0013678 from April 2015 to April 2016. His research during this year focused on the phenomenology of super-symmetry (SUSY) and maximizing its future discovery potential at Run II of the LHC. SUSY is one of the most well-motivated frameworks for physics beyond the Standard Model. It solves the 'naturalness' or 'hierarchy' problem by stabilizing the Higgs mass against otherwise uncontrolled quantum corrections, predicts 'grand unification' of the fundamental forces, and provides many potential candidates for dark matter. However, after decades of null results from direct and indirect searches, the viable parameter space for SUSY is increasingly constrained. Also, the discovery of a Standard Model-like Higgs with a mass at 125 GeV places a stringent constraint on SUSY models. In the work supported on this grant, Shih has worked on four different projects motivated by these issues. He has built natural SUSY models that explain the Higgs mass and provide viable dark matter; he has studied the parameter space of 'gauge mediated supersymmetry breaking' (GMSB) that satisfies the Higgs mass constraint; he has developed new tools for the precision calculation of flavor and CP observables in general SUSY models; and he has studied new techniques for discovery of supersymmetric partners of the top quark.

  4. Higgs CAT

    Energy Technology Data Exchange (ETDEWEB)

    Passarino, Giampiero [Universita di Torino, Dipartimento di Fisica Teorica, Turin (Italy); INFN, Sezione di Torino, Turin (Italy)

    2014-05-15

    Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape (..and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the gg → ZZ process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis. (orig.)

  5. Higgs CAT

    International Nuclear Information System (INIS)

    Passarino, Giampiero

    2014-01-01

    Higgs Computed Axial Tomography, an excerpt. The Higgs boson lineshape (..and the devil hath power to assume a pleasing shape, Hamlet, Act II, scene 2) is analyzed for the gg → ZZ process, with special emphasis on the off-shell tail which shows up for large values of the Higgs virtuality. The effect of including background and interference is also discussed. The main focus of this work is on residual theoretical uncertainties, discussing how much-improved constraint on the Higgs intrinsic width can be revealed by an improved approach to analysis. (orig.)

  6. CP Studies and Non-Standard Higgs Physics

    DEFF Research Database (Denmark)

    Kraml, S.; Accomando, E.; G. Akeroyd, A.

    2006-01-01

    There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state......, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories...

  7. Natural Higgs mass in supersymmetry from nondecoupling effects.

    Science.gov (United States)

    Lu, Xiaochuan; Murayama, Hitoshi; Ruderman, Joshua T; Tobioka, Kohsaku

    2014-05-16

    The Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Nondecoupling effects can boost the Higgs mass when new states interact with the Higgs boson, but new sources of SUSY breaking that accompany such extensions threaten naturalness. We show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. We explore the modified Higgs phenomenology of this scenario, which we call the "Dirac next-to-minimal supersymmetric standard model."

  8. Higgs Particle: The Origin of Mass

    OpenAIRE

    Okada, Yasuhiro

    2007-01-01

    The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generat...

  9. Workshop on CP Studies and Non-Standard Higgs Physics

    CERN Document Server

    Accomando, E.; Akhmetzyanova, E.; Albert, J.; Alves, A.; Amapane, N.; Aoki, M.; Azuelos, G.; Baffioni, S.; Ballestrero, A.; Barger, V.; Bartl, A.; Bechtle, P.; Blanger, G.; Belhouari, A.; Bellan, R.; Belyaev, A.; Benes, Petr; Benslama, K.; Bernreuther, W.; Besanon, M.; Bevilacqua, G.; Beyer, M.; Bluj, M.; Bolognesi, S.; Boonekamp, M.; Borzumati, Francesca; Boudjema, F.; Brandenburg, A.; Brauner, Tomas; Buszello, C.P.; Butterworth, J.M.; Carena, Marcela; Cavalli, D.; Cerminara, G.; Choi, S.Y.; Clerbaux, B.; Collard, C.; Conley, John A.; Deandrea, A.; De Curtis, S.; Dermisek, R.; De Roeck, A.; Dewhirst, G.; Diaz, M.A.; Diaz-Cruz, J.L.; Dietrich, D.D.; Dolgopolov, M.; Dominici, D.; Dubinin, M.; Eboli, O.; Ellis, John R.; Evans, N.; Fano, L.; Ferland, J.; Ferrag, S.; Fitzgerald, S.P.; Fraas, H.; Franke, F.; Gennai, S.; Ginzburg, I.F.; Godbole, R.M.; Gregoire, T.; Grenier, Gerald Jean; Grojean, C.; Gudnason, S.B.; Gunion, J.F.; Haber, H.E.; Hahn, T.; Han, T.; Hankele, V.; Hays, Christopher Paul; Heinemeyer, S.; Hesselbach, S.; Hewett, J.L.; Hidaka, K.; Hirsch, M.; Hollik, W.; Hooper, D.; Hosek, J.; Hubisz, J.; Hugonie, C.; Kalinowski, J.; Kanemura, S.; Kashkan, V.; Kernreiter, T.; Khater, W.; Khoze, V.A.; Kilian, W.; King, S.F.; Kittel, O.; Klamke, G.; Kneur, J.L.; Kouvaris, C.; Kraml, S.; Krawczyk, M.; Krstonoic, P.; Kyriakis, A.; Langacker, P.; Le, M.P.; Lee, H.-S.; Lee, J.S.; Lemaire, M.C.; Liao, Y.; Lillie, B.; Litvine, Vladimir A.; Logan, H.E.; McElrath, Bob; Mahmoud, T.; Maina, E.; Mariotti, C.; Marquard, P.; Martin, A.D.; Mazumdar, K.; Miller, D.J.; Min, P.; Monig, Klaus; Moortgat-Pick, G.; Moretti, S.; Muhlleitner, M.M.; Munir, S.; Nevzorov, R.; Newman, H.; Niezurawski, P.; Nikitenko, A.; Noriega-Papaqui, R.; Okada, Y.; Osland, P.; Pilaftsis, A.; Porod, W.; Przysiezniak, H.; Pukhov, A.; Rainwater, D.; Raspereza, A.; Reuter, J.; Riemann, S.; Rindani, S.; Rizzo, T.G.; Ros, E.; Rosado, A.; Rousseau, D.; Roy, D.P.; Ryskin, M.G.; Rzehak, H.; Sannino, F.; Schmidt, E.; Schrder, H.; Schumacher, M.; Semenov, A.; Senaha, E.; Shaughnessy, G.; Singh, R.K.; Terning, J.; Vacavant, L.; Velasco, M.; Villanova del Moral, Albert; von der Pahlen, F.; Weiglein, G.; Williams, J.; Williams, K.E.; Zarnecki, A.F.; Zeppenfeld, D.; Zerwas, D.; Zerwas, P.M.; Zerwekh, A.R.; Ziethe, J.; 2nd Workshop on CP Studies and Non-standard Higgs Physics; 3rd Workshop on CP Studies and Non-standard Higgs Physics; 4th Workshop on CP Studies and Non-standard Higgs Physics; CPNSH; Workshop on CP Studies and Non-standard Higgs Physics; CP Studies and Non-Standard Higgs Physics

    2006-01-01

    There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents ...

  10. Four generations and Higgs physics

    Energy Technology Data Exchange (ETDEWEB)

    Kribs, Graham D. [Department of Physics and Institute of Theoretical Science, University of Oregon, Eugene (United States); Plehn, Tilman [SUPA, School of Physics, University of Edinburgh (United Kingdom); Spannowsky, Michael [Institut fuer Theoretische Physik, Universitaet Karlsruhe (Germany); Tait, Tim M.P. [HEP Division, Argonne National Laboratory (United States)

    2008-07-01

    A fourth generation has been considered and forgotten or discarded several times, wrongly leaving the impression that it is either ruled out or disfavored by experimental data. We revisit a fourth generation of chiral matter in the light of present electroweak precision data and deduce effects on Higgs phenomenology. We find a chiral fourth generation to be a viable model which can yield interesting signatures at the LHC, e.g. production rates are enhanced, weak-boson-fusion channels are suppressed, angular distributions are modified and Higgs pairs can be observed.

  11. Status of the charged Higgs boson in two Higgs doublet models

    Science.gov (United States)

    Arbey, A.; Mahmoudi, F.; Stål, O.; Stefaniak, T.

    2018-03-01

    The existence of charged Higgs boson(s) is inevitable in models with two (or more) Higgs doublets. Hence, their discovery would constitute unambiguous evidence for new physics beyond the Standard Model (SM). Taking into account all relevant results from direct charged and neutral Higgs boson searches at LEP and the LHC, as well as the most recent constraints from flavour physics, we present a detailed analysis of the current phenomenological status of the charged Higgs sector in a variety of well-motivated two Higgs doublet models (2HDMs). We find that charged Higgs bosons as light as 75 GeV can still be compatible with the combined data, although this implies severely suppressed charged Higgs couplings to all fermions. In more popular models, e.g. the 2HDM of Type II, we find that flavour physics observables impose a combined lower limit on the charged Higgs mass of M_{H^± } ≳ 600 GeV - independent of tan β - which increases to M_{H^± } ≳ 650 GeV for tan β < 1. We furthermore find that in certain scenarios, the signature of a charged Higgs boson decaying into a lighter neutral Higgs boson and a W boson provides a promising experimental avenue that would greatly complement the existing LHC search programme for charged Higgs boson(s).

  12. Status of the charged Higgs boson in two Higgs doublet models

    International Nuclear Information System (INIS)

    Arbey, A.; Mahmoudi, F.; Stefaniak, T.; Staal, O.

    2018-01-01

    The existence of charged Higgs boson(s) is inevitable in models with two (or more) Higgs doublets. Hence, their discovery would constitute unambiguous evidence for new physics beyond the Standard Model (SM). Taking into account all relevant results from direct charged and neutral Higgs boson searches at LEP and the LHC, as well as the most recent constraints from flavour physics, we present a detailed analysis of the current phenomenological status of the charged Higgs sector in a variety of well-motivated two Higgs doublet models (2HDMs). We find that charged Higgs bosons as light as 75 GeV can still be compatible with the combined data, although this implies severely suppressed charged Higgs couplings to all fermions. In more popular models, e.g. the 2HDM of Type II, we find that flavour physics observables impose a combined lower limit on the charged Higgs mass of M H ± > or similar 600 GeV - independent of tan β - which increases to M H ± > or similar 650 GeV for tan β < 1. We furthermore find that in certain scenarios, the signature of a charged Higgs boson decaying into a lighter neutral Higgs boson and a W boson provides a promising experimental avenue that would greatly complement the existing LHC search programme for charged Higgs boson(s). (orig.)

  13. Search for Charged Higgs Bosons with the ATLAS Detector

    CERN Document Server

    Barak, L; The ATLAS collaboration

    2014-01-01

    Several non-minimal Higgs scenarios, e.g. Two Higgs Doublet Models (2HDM), predict the existence of charged Higgs bosons. This talk describes searches for charged Higgs bosons produced in top quark decays, in association with a top quark, or decaying to a tau lepton and a neutrino using the Run I data collected by the ATLAS detector at the LHC.

  14. Prediction of e± elastic scattering cross-section ratio based on phenomenological two-photon exchange corrections

    Science.gov (United States)

    Qattan, I. A.

    2017-06-01

    I present a prediction of the e± elastic scattering cross-section ratio, Re+e-, as determined using a new parametrization of the two-photon exchange (TPE) corrections to electron-proton elastic scattering cross section σR. The extracted ratio is compared to several previous phenomenological extractions, TPE hadronic calculations, and direct measurements from the comparison of electron and positron scattering. The TPE corrections and the ratio Re+e- show a clear change of sign at low Q2, which is necessary to explain the high-Q2 form factors discrepancy while being consistent with the known Q2→0 limit. While my predictions are in generally good agreement with previous extractions, TPE hadronic calculations, and existing world data including the recent two measurements from the CLAS and VEPP-3 Novosibirsk experiments, they are larger than the new OLYMPUS measurements at larger Q2 values.

  15. Higgs bosons in the standard model, the MSSM and beyond

    Indian Academy of Sciences (India)

    Abstract. I summarize the basic theory and selected phenomenology for the Higgs boson(s) of the standard model, the minimal supersymmetric model and some extensions thereof, including the next-to-minimal supersymmetric model.

  16. Little Higgs models and T parity

    International Nuclear Information System (INIS)

    Perelstein, Maxim

    2006-01-01

    Little Higgs models are an interesting extension of the standard model at the TeV scale. They provide a simple and attractive mechanism of electroweak symmetry breaking. We review one of the simplest models of this class, the littlest Higgs model, and its extension with T parity. The model with T parity satisfies precision electroweak constraints without fine-tuning, contains an attractive dark matter candidate, and leads to interesting phenomenology at the Large Hadron Collider (LHC). (author)

  17. Higgs physics

    Indian Academy of Sciences (India)

    The theoretical aspects of the physics of Higgs bosons are reviewed focussing on the elements that are relevant for the production and detection at present hadron colliders. After briefly summarizing the basics of electroweak symmetry breaking in the Standard Model, the Higgs production at the LHC and at the Tevatron is ...

  18. A tale of twin Higgs: natural twin two Higgs doublet models

    International Nuclear Information System (INIS)

    Yu, Jiang-Hao

    2016-01-01

    In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ 2 breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ 2 breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ 2 symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ 2 breaking, radiative ℤ 2 breaking, tadpole-induced ℤ 2 breaking, and quartic-induced ℤ 2 breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.

  19. Probing the Higgs self coupling via single Higgs production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Degrassi, G. [Dipartimento di Matematica e Fisica, Università di Roma Tre andINFN, sezione di Roma Tre,Via della Vasca Navale 84, I-00146 Rome (Italy); Giardino, P.P. [Physics Department, Brookhaven National Laboratory,20 Pennsylvania St., Upton NY 11742 (United States); Maltoni, F.; Pagani, D. [Centre for Cosmology, Particle Physics and Phenomenology (CP3),Université Catholique de Louvain,B-1348 Louvain-la-Neuve (Belgium)

    2016-12-16

    We propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. The method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, tt̄H) and decay (γγ, WW{sup ∗}/ZZ{sup ∗}→4f, bb̄, ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We find that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.

  20. A tale of twin Higgs: natural twin two Higgs doublet models

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jiang-Hao [Amherst Center for Fundamental Interactions, Department of Physics,University of Massachusetts Amherst,710 North Pleasant St., Amherst, MA 01002 (United States)

    2016-12-28

    In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ{sub 2} breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ{sub 2} breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ{sub 2} symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ{sub 2} breaking, radiative ℤ{sub 2} breaking, tadpole-induced ℤ{sub 2} breaking, and quartic-induced ℤ{sub 2} breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.

  1. Single Higgs-boson production at a photon-photon collider: General 2HDM versus MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Val, David, E-mail: lopez@thphys.uni-heidelberg.de [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany); Sola, Joan, E-mail: sola@ecm.ub.es [High Energy Physics Group, Dept. ECM, and Institut de Ciencies del Cosmos Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain)

    2011-08-19

    We revisit the production of a single Higgs boson from direct {gamma}{gamma}-scattering at a photon collider. We compute the total cross-section {sigma}({gamma}{gamma}{yields}h) (for h=h{sup 0},H{sup 0},A{sup 0}), and the strength of the effective g{sub h}{sup 0}{sub {gamma}{gamma}} coupling normalized to the Standard Model (SM), for both the general Two-Higgs-Doublet Model (2HDM) and the Minimal Supersymmetric Standard Model (MSSM). In both cases the predicted production rates for the CP-even (odd) states render up to 10{sup 4} (10{sup 3}) events per 500 fb{sup -1} of integrated luminosity, in full consistency with all the theoretical and phenomenological constraints. Depending on the channel the maximum rates can be larger or smaller than the SM expectations, but in most of the parameter space they should be well measurable. We analyze how these departures depend on the dynamics underlying each of the models, supersymmetric and non-supersymmetric, and highlight the possible distinctive phenomenological signatures. We demonstrate that this process could be extremely useful to discern non-supersymmetric Higgs bosons from supersymmetric ones. Furthermore, in the MSSM case, we show that {gamma}{gamma}-physics could decisively help to overcome the serious impasse afflicting Higgs boson physics at the infamous 'LHC wedge'.

  2. Understanding phenomenology.

    LENUS (Irish Health Repository)

    Flood, Anne

    2012-01-31

    Phenomenology is a philosophic attitude and research approach. Its primary position is that the most basic human truths are accessible only through inner subjectivity, and that the person is integral to the environment. This paper discusses the theoretical perspectives related to phenomenology, and includes a discussion of the methods adopted in phenomenological research.

  3. Phenomenology of non-universal gaugino masses and implications ...

    Indian Academy of Sciences (India)

    universal gaugino masses for the phenomenology of Higgs bosons in the context of large hadron collider. Keywords. Supersymmetry; non-universal gaugino masses; Higgs bosons. PACS Nos 12.60.Jv; 11.30.Er; 14.80.Ly. 1. Introduction.

  4. Higgs pair production: choosing benchmarks with cluster analysis

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Alexandra; Dall’Osso, Martino; Dorigo, Tommaso [Dipartimento di Fisica e Astronomia and INFN, Sezione di Padova,Via Marzolo 8, I-35131 Padova (Italy); Goertz, Florian [CERN,1211 Geneva 23 (Switzerland); Gottardo, Carlo A. [Physikalisches Institut, Universität Bonn,Nussallee 12, 53115 Bonn (Germany); Tosi, Mia [CERN,1211 Geneva 23 (Switzerland)

    2016-04-20

    New physics theories often depend on a large number of free parameters. The phenomenology they predict for fundamental physics processes is in some cases drastically affected by the precise value of those free parameters, while in other cases is left basically invariant at the level of detail experimentally accessible. When designing a strategy for the analysis of experimental data in the search for a signal predicted by a new physics model, it appears advantageous to categorize the parameter space describing the model according to the corresponding kinematical features of the final state. A multi-dimensional test statistic can be used to gauge the degree of similarity in the kinematics predicted by different models; a clustering algorithm using that metric may allow the division of the space into homogeneous regions, each of which can be successfully represented by a benchmark point. Searches targeting those benchmarks are then guaranteed to be sensitive to a large area of the parameter space. In this document we show a practical implementation of the above strategy for the study of non-resonant production of Higgs boson pairs in the context of extensions of the standard model with anomalous couplings of the Higgs bosons. A non-standard value of those couplings may significantly enhance the Higgs boson pair-production cross section, such that the process could be detectable with the data that the LHC will collect in Run 2.

  5. Higgs triplets in the standard model

    International Nuclear Information System (INIS)

    Gunion, J.F.; Vega, R.; Wudka, J.

    1990-01-01

    Even though the standard model of the strong and electroweak interactions has proven enormously successful, it need not be the case that a single Higgs-doublet field is responsible for giving masses to the weakly interacting vector bosons and the fermions. In this paper we explore the phenomenology of a Higgs sector for the standard model which contains both doublet and triplet fields [under SU(2) L ]. The resulting Higgs bosons have many exotic features and surprising experimental signatures. Since a critical task of future accelerators will be to either discover or establish the nonexistence of Higgs bosons with mass below the TeV scale, it will be important to keep in mind the alternative possibilities characteristic of this and other nonminimal Higgs sectors

  6. Standard model Higgs physics at colliders

    International Nuclear Information System (INIS)

    Rosca, A.

    2007-01-01

    In this report we briefly review the experimental status and prospects to verify the Higgs mechanism of spontaneous symmetry breaking. The focus is on the most relevant aspects of the phenomenology of the Standard Model Higgs boson at current (Tevatron) and future (Large Hadron Collider, LHC and International Linear Collider, ILC) particle colliders. We review the Standard Model searches: searches at the Tevatron, the program planned at the LHC and prospects at the ILC. Emphasis is put on what follows after a candidate discovery at the LHC: the various measurements which are necessary to precisely determine what the properties of this Higgs candidate are. (author)

  7. NMSSM interpretations of the observed Higgs signal

    International Nuclear Information System (INIS)

    Domingo, Florian; Weiglein, Georg

    2015-01-01

    While the properties of the signal that was discovered in the Higgs searches at the LHC are consistent so far with the Higgs boson of the Standard Model (SM), it is crucial to investigate to what extent other interpretations that may correspond to very different underlying physics are compatible with the current results. We use the Next-to-Minimal Supersymmetric Standard Model (NMSSM) as a well-motivated theoretical framework with a sufficiently rich Higgs phenomenology to address this question, making use of the public tools HiggsBounds and HiggsSignals in order to take into account comprehensive experimental information on both the observed signal and on the existing limits from Higgs searches at LEP, the TeVatron and the LHC. We find that besides the decoupling limit resulting in a single light state with SM-like properties, several other configurations involving states lighter or quasi-degenerate with the one at about 125 GeV turn out to give a competitive fit to the Higgs data and other existing constraints. We discuss the phenomenology and possible future experimental tests of those scenarios, and compare the features of specific scenarios chosen as examples with those arising from a more global fit.

  8. CP Violation in Heavy MSSM Higgs Scenarios

    CERN Document Server

    Carena, M; Lee, J S; Pilaftsis, A; Wagner, C E M

    2016-01-01

    We introduce and explore new heavy Higgs scenarios in the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation, which have important phenomenological implications that may be testable at the LHC. For soft supersymmetry-breaking scales M_S above a few TeV and a charged Higgs boson mass M_H+ above a few hundred GeV, new physics effects including those from explicit CP violation decouple from the light Higgs boson sector. However, such effects can significantly alter the phenomenology of the heavy Higgs bosons while still being consistent with constraints from low-energy observables, for instance electric dipole moments. To consider scenarios with a charged Higgs boson much heavier than the Standard Model (SM) particles but much lighter than the supersymmetric particles, we revisit previous calculations of the MSSM Higgs sector. We compute the Higgs boson masses in the presence of CP violating phases, implementing improved matching and renormalization group (RG) effects, as well as two-loop RG...

  9. Higgs searches and prospects at CDF

    International Nuclear Information System (INIS)

    Pavel A Murat

    2003-01-01

    The Standard model of electroweak interactions (SM) has been extremely successful in describing interactions of elementary particles over the last decades. The Higgs scalar boson is one of the key elements of the SM: Higgs interactions with the other particles generate the particle masses and allow to keep the theory renormalizable at electroweak scale. All the particles predicted by the SM but the Higgs boson have already been observed experimentally and therefore search for the Higgs is one of the most important scientific goals for high energy physics. The current lower limit on the SM Higgs mass M H > 114.4 GeV at 95% CL has been established by LEP experiments. In this paper we review CDF Run I results on Higgs searches including the Higgs bosons predicted by the minimal supersymmetric extention of the Standard Model (MSSM) and discuss the Run II prospects

  10. Strength of the trilinear Higgs boson coupling in technicolor models

    International Nuclear Information System (INIS)

    Doff, A.; Natale, A.A.

    2006-01-01

    In the standard model of elementary particles the fermion and gauge boson masses are generated due to the interaction of these particles with elementary Higgs scalar bosons. Despite its success there are some points in the model as, for instance, the enormous range of masses between the lightest and heaviest fermions and other peculiarities that could be better explained at a deeper level. The nature of the Higgs boson is one of the most important problems in particle physics, and there are many questions that may be answered in the near future by LHC experiments, such as: Is the Higgs boson, if it exists at all, elementary or composite? What are the symmetries behind the Higgs mechanism? There are many variants for the Higgs mechanism. Our interest in this work will be focused in the models of electroweak symmetry breaking via strongly interacting theories of technicolor (TC) type. In these theories the Higgs boson is a composite of the so called technifermions, and at some extent any model where the Higgs boson is not an elementary field follows more or less the same ideas of the technicolor models. In extensions of the standard model the scalar self-couplings can be enhanced, like in the supersymmetric version. If the same happens in models of dynamical symmetry breaking, as far as we know, has not been investigated up to now, and this study is the motivation of our work. Although technicolor is a non-Abelian gauge theory it is not necessarily similar to QCD, and most of the work in this area try to find the TC dynamics dealing with the particle content of the theory in order to obtain a technifermion self-energy that does not lead to phenomenological problems as in the scheme known as walking technicolor. In this work we will consider a very general Ansatz for the technifermion self-energy, which is an essential ingredient to compute the scalar self-couplings. This Ansatz interpolates between all known forms of technifermionic self-energy. As we vary some

  11. Higgs physics as a proble of new physics

    International Nuclear Information System (INIS)

    KANEMURA, S.

    2014-01-01

    The discovery of the Higgs boson at the LHC has opened the door to clarifying the mechanism of electroweak symmetry breaking and the origin of particle masses. The Higgs sector in the SM is the simplest possible one but is not based on a fundamental theoretical principle, so that there is also the possibility of non-minimal Higgs sectors. While the standard model is not in contradiction with current LHC data within the errors, many extended Higgs sectors can also reproduce these data. An extended Higgs sector often appears in new physics models beyond the standard model, so that this allows to determine new physics from the Higgs sector. In this talk, we discuss various aspects of extended Higgs sectors, in particular their phenomenological properties and testability at future experiments, as the International Linear Collider.

  12. Vector and Axial-vector resonances in composite models of the Higgs boson

    DEFF Research Database (Denmark)

    Franzosi, Diogo Buarque; Cacciapaglia, Giacomo; Cai, Haiying

    2016-01-01

    We provide a non-linear realisation of composite Higgs models in the context of the SU(4)/Sp(4) symmetry breaking pattern, where the effective Lagrangian of the spin-0 and spin-1 resonances is constructed via the CCWZ prescription using the Hidden Symmetry formalism. We investigate the EWPT const...... as a template for the phenomenology of composite Higgs models at the LHC and at future 100 TeV colliders, as well as for other application. In this work, we focus on the formalism for spin-1 resonances and their bounds from di-lepton and di-boson searches at the LHC.......We provide a non-linear realisation of composite Higgs models in the context of the SU(4)/Sp(4) symmetry breaking pattern, where the effective Lagrangian of the spin-0 and spin-1 resonances is constructed via the CCWZ prescription using the Hidden Symmetry formalism. We investigate the EWPT...... constraints by accounting the effects from reduced Higgs couplings and integrating out heavy spin-1 resonances. This theory emerges from an underlying theory of gauge interactions with fermions, thus first principle lattice results predict the massive spectrum in composite Higgs models. This model can be used...

  13. Higgs Discovery

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2013-01-01

    has been challenged by the discovery of a not-so-heavy Higgs-like state. I will therefore review the recent discovery \\cite{Foadi:2012bb} that the standard model top-induced radiative corrections naturally reduce the intrinsic non-perturbative mass of the composite Higgs state towards the desired...... via first principle lattice simulations with encouraging results. The new findings show that the recent naive claims made about new strong dynamics at the electroweak scale being disfavoured by the discovery of a not-so-heavy composite Higgs are unwarranted. I will then introduce the more speculative......I discuss the impact of the discovery of a Higgs-like state on composite dynamics starting by critically examining the reasons in favour of either an elementary or composite nature of this state. Accepting the standard model interpretation I re-address the standard model vacuum stability within...

  14. Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector

    Energy Technology Data Exchange (ETDEWEB)

    de Florian, D. [National Univ. of San Martin, Buenos Aires (Argentina); et al.

    2016-10-25

    This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions of Higgs boson production cross sections and decay branching ratios, parton distribution functions, and off-shell Higgs boson production and interference effects. The second part discusses the recent progress in Higgs effective field theory predictions, followed by the third part on pseudo-observables, simplified template cross section and fiducial cross section measurements, which give the baseline framework for Higgs boson property measurements. The fourth part deals with the beyond the Standard Model predictions of various benchmark scenarios of Minimal Supersymmetric Standard Model, extended scalar sector, Next-to-Minimal Supersymmetric Standard Model and exotic Higgs boson decays. This report follows three previous working-group reports: Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002), Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002), and Handbook of LHC Higgs Cross Sections: 3. Higgs properties (CERN-2013-004). The current report serves as the baseline reference for Higgs physics in LHC Run 2 and beyond.

  15. Present status and future prospects for a Higgs boson discovery at the Tevatron and LHC

    International Nuclear Information System (INIS)

    Haber, Howard E

    2010-01-01

    Discovering the Higgs boson is one of the primary goals of both the Tevatron and the Large Hadron Collider (LHC). The present status of the Higgs search is reviewed and future prospects for discovery at the Tevatron and LHC are considered. This talk focuses primarily on the Higgs boson of the Standard Model and its minimal supersymmetric extension. Theoretical expectations for the Higgs boson and its phenomenological consequences are reviewed.

  16. A phenomenological prediction of dryout based on the churn-to-annular flow transition criterion in uniformly heated vertical tubes

    International Nuclear Information System (INIS)

    Hong, Sung-Deok; Chun, Se-Young; Yang, Sun-Kyu; Chung, Moon-Ki; Lashgari, Farbod

    2000-01-01

    A phenomenological model is proposed to predict dryout in uniformly heated vertical tubes. The major point of the study was refining the initial conditions at the onset of annular flow location that starts the liquid film dryout process. The void fraction at the onset of the annular flow location has been derived from the vapor superficial velocity obtained by the churn-to-annular flow criterion with the help of the void-quality relationship. The thermodynamic equilibrium quality calculated through the iteration of flow quality using the profile-fit model to find the accurate starting point of the annular-flow in a tube. The present method was validated by worldwide data covering wide parametric ranges, a diameter of 5.1-37.5, exit quality over 10%, a flow rate of 183-5261 kg/m 2 -s and a system pressure of 0.5-17.7 MPa. The churn-to-annular flow transition criterion of Taitel et al.'s shows better prediction results than the other transition criteria. The present model improved the CHF prediction capability as a mean of 0.97 and root mean square error of 11% for the 3883 experimental data and extended the applicable range to the relatively low quality region. (author)

  17. Constraints on the mass spectrum of fourth generation fermions and Higgs bosons

    International Nuclear Information System (INIS)

    Hashimoto, Michio

    2010-01-01

    We reanalyze constraints on the mass spectrum of the chiral fourth generation fermions and the Higgs bosons for the standard model (SM4) and the two Higgs doublet model. We find that the Higgs mass in the SM4 should be larger than roughly the fourth generation up-type quark mass, while the light CP even Higgs mass in the two Higgs doublet model can be smaller. Various mass spectra of the fourth generation fermions and the Higgs bosons are allowed. The phenomenology of the fourth generation models is still rich.

  18. Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider

    International Nuclear Information System (INIS)

    Singhal, Jai Kumar; Singh, Sardar; Nagawat, Ashok K.

    2007-01-01

    We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tanβ and m A . We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson. (author)

  19. Higgs-Palatini inflation and unitarity

    International Nuclear Information System (INIS)

    Bauer, Florian; Demir, Durmus A.

    2011-01-01

    In the Higgs inflation scenario the Higgs field is strongly coupled to the Ricci scalar in order to drive primordial inflation. However, in its original form in pure metric formulation of gravity, the ultraviolet (UV) cutoff of the Higgs interactions and the Hubble rate are of the same magnitude, and this makes the whole inflationary evolution dependent of the unknown UV completion of the Higgs sector. This problem, the unitarity violation, plagues the Higgs inflation scenario. In this Letter we show that, in the Palatini formulation of gravitation, Higgs inflation does not suffer from unitarity violation since the UV cutoff lies parametrically much higher than the Hubble rate so that unknown UV physics does not disrupt the inflationary dynamics. Higgs-Palatini inflation, as we call it, is, therefore, UV-safe, minimal and endowed with predictive power.

  20. An Ultraviolet Chiral Theory of the Top for the Fundamental Composite (Goldstone) Higgs

    DEFF Research Database (Denmark)

    Cacciapaglia, Giacomo; Sannino, Francesco

    2016-01-01

    We introduce a scalar-less anomaly free chiral gauge theory that serves as natural ultraviolet completion of models of fundamental composite (Goldstone) Higgs dynamics. The new theory is able to generate the top mass and furthermore features a built-in protection mechanism that naturally suppresses...... the bottom mass. At low energies the theory predicts new fractionally charged fermions, and a number of four-fermion operators that, besides being relevant for the generation of the top mass, also lead to an intriguing phenomenology for the new states predicted by the theory....

  1. An ultraviolet chiral theory of the top for the fundamental composite (Goldstone) Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Cacciapaglia, Giacomo, E-mail: g.cacciapaglia@ipnl.in2p3.fr [Univ Lyon, Université Lyon 1, CNRS/IN2P3, IPNL, 4 rue Enrico Fermi, F-69622 Villeurbanne Cedex (France); Sannino, Francesco, E-mail: sannino@cp3.dias.sdu.dk [CP" 3-Origins and the Danish IAS, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

    2016-04-10

    We introduce a scalar-less anomaly free chiral gauge theory that serves as natural ultraviolet completion of models of fundamental composite (Goldstone) Higgs dynamics. The new theory is able to generate the top mass and furthermore features a built-in protection mechanism that naturally suppresses the bottom mass. At low energies the theory predicts new fractionally charged fermions, and a number of four-fermion operators that, besides being relevant for the generation of the top mass, also lead to an intriguing phenomenology for the new states predicted by the theory.

  2. Profile of a nonstandard Higgs boson at the CERN LHC

    International Nuclear Information System (INIS)

    Kominis, D.; Koulovassilopoulos, V.

    1995-01-01

    In a wide class of extensions of the standard model there is a scalar resonance with the quantum numbers of the usual Higgs boson but with different couplings to fermions and gauge bosons. Using an effective Lagrangian description, we examine the phenomenology of such a generic nonstandard Higgs boson at the CERN LHC. In particular, we determine the circumstances under which such a particle can be observed in its ZZ decay mode and distinguished from the Higgs boson of the standard model. We briefly comment on the energy scale effectively probed at the LHC, if the nonstandard nature of an observed Higgs particle can be asserted

  3. Exceptional phenomenology

    DEFF Research Database (Denmark)

    Aggerholm, Kenneth; Moltke Martiny, Kristian

    Phenomenological research is in traditional terms a matter of going 'back to the things themselves', as Husserl famously stated. But if phenomenology is to renew itself in creative ways and reveal new aspects of human experience it is of value to look for a certain kind of phenomena: exceptions. ...

  4. Problems of phenomenological description of elastic pp scattering at the LHC predictions of contemporary models

    CERN Document Server

    Kundrát, Vojtech; Kaspar, Jan; Procházka, Jirí

    2010-01-01

    The standard description of common influence of both the Coulomb and hadronic elastic scattering in the proton - proton elastic collisions at high energies with the help of West and Yennie complete amplitude is shown to be theoretically inconsistent. The approach being based on the eikonal model amplitude removes these troubles. The preference of its applica- tion to the analysis of experimental data and in obtaining the predictions of contemporary models for proton - proton high energy elastic hadronic scattering are discussed.

  5. Higgs Physics

    CERN Document Server

    Grojean, C.

    2016-01-01

    The cause of the screening of the weak interactions at long distances puzzled the high-energy community for more nearly half a century. With the discovery of the Higgs boson a new era started with direct experimental information on the physics behind the breaking of the electroweak symmetry. This breaking plays a fundamental role in our understanding of particle physics and sits at the high-energy frontier beyond which we expect new physics that supersedes the Standard Model. The Higgs boson (inclusive and differential) production and decay rates offer a new way to probe this frontier.

  6. Phenomenological Lagrangians

    International Nuclear Information System (INIS)

    Weinberg, S.

    1979-01-01

    The author presents an argument that phenomenological Lagrangians can be used not only to reproduce the soft pion results of current algebra, but also to justify these results, without any use of operator algebra, and shows how phenomenological Lagrangians can be used to calculate corrections to the leading soft pion results to any desired order in external momenta. The renormalization group is used to elucidate the structure of these corrections. Corrections due to the finite mass of the pion are treated and speculations are made about another possible application of phenomenological Lagrangians. (Auth.)

  7. Disentangling a dynamical Higgs

    International Nuclear Information System (INIS)

    Brivio, I.; Corbett, T.; Éboli, O.J.P.; Gavela, M.B.; Gonzalez-Fraile, J.; Gonzalez-Garcia, M.C.; Merlo, L.; Rigolin, S.

    2014-01-01

    The pattern of deviations from Standard Model predictions and couplings is different for theories of new physics based on a non-linear realization of the SU(2) L ×U(1) Y gauge symmetry breaking and those assuming a linear realization. We clarify this issue in a model-independent way via its effective Lagrangian formulation in the presence of a light Higgs particle, up to first order in the expansions: dimension-six operators for the linear expansion and four derivatives for the non-linear one. Complete sets of gauge and gauge-Higgs operators are considered, implementing the renormalization procedure and deriving the Feynman rules for the non-linear expansion. We establish the theoretical relation and the differences in physics impact between the two expansions. Promising discriminating signals include the decorrelation in the non-linear case of signals correlated in the linear one: some pure gauge versus gauge-Higgs couplings and also between couplings with the same number of Higgs legs. Furthermore, anomalous signals expected at first order in the non-linear realization may appear only at higher orders of the linear one, and vice versa. We analyze in detail the impact of both type of discriminating signals on LHC physics

  8. Disentangling a dynamical Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Brivio, I. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Corbett, T. [C.N. Yang Institute for Theoretical Physics and Department of Physics and Astronomy,SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States); Éboli, O.J.P. [Instituto de Física, Universidade de São Paulo,C.P. 66318, 05315-970, São Paulo SP (Brazil); Gavela, M.B. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Gonzalez-Fraile, J. [Departament d’Estructura i Constituents de la Matèria and ICC-UB, Universitat de Barcelona,647 Diagonal, E-08028 Barcelona (Spain); Gonzalez-Garcia, M.C. [Institució Catalana de Recerca i Estudis Avançats (ICREA),Passeig Lluís Companys, 23, E-08010 Barcelona (Spain); Departament d’Estructura i Constituents de la Matèria and ICC-UB, Universitat de Barcelona,647 Diagonal, E-08028 Barcelona (Spain); C.N. Yang Institute for Theoretical Physics and Department of Physics and Astronomy,SUNY at Stony Brook, Stony Brook, NY 11794-3840 (United States); Merlo, L. [Departamento de Física Teórica and Instituto de Física Teórica, IFT-UAM/CSIC,Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid (Spain); Rigolin, S. [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padua (Italy)

    2014-03-05

    The pattern of deviations from Standard Model predictions and couplings is different for theories of new physics based on a non-linear realization of the SU(2){sub L}×U(1){sub Y} gauge symmetry breaking and those assuming a linear realization. We clarify this issue in a model-independent way via its effective Lagrangian formulation in the presence of a light Higgs particle, up to first order in the expansions: dimension-six operators for the linear expansion and four derivatives for the non-linear one. Complete sets of gauge and gauge-Higgs operators are considered, implementing the renormalization procedure and deriving the Feynman rules for the non-linear expansion. We establish the theoretical relation and the differences in physics impact between the two expansions. Promising discriminating signals include the decorrelation in the non-linear case of signals correlated in the linear one: some pure gauge versus gauge-Higgs couplings and also between couplings with the same number of Higgs legs. Furthermore, anomalous signals expected at first order in the non-linear realization may appear only at higher orders of the linear one, and vice versa. We analyze in detail the impact of both type of discriminating signals on LHC physics.

  9. Fitting the Phenomenological MSSM

    CERN Document Server

    AbdusSalam, S S; Quevedo, F; Feroz, F; Hobson, M

    2010-01-01

    We perform a global Bayesian fit of the phenomenological minimal supersymmetric standard model (pMSSM) to current indirect collider and dark matter data. The pMSSM contains the most relevant 25 weak-scale MSSM parameters, which are simultaneously fit using `nested sampling' Monte Carlo techniques in more than 15 years of CPU time. We calculate the Bayesian evidence for the pMSSM and constrain its parameters and observables in the context of two widely different, but reasonable, priors to determine which inferences are robust. We make inferences about sparticle masses, the sign of the $\\mu$ parameter, the amount of fine tuning, dark matter properties and the prospects for direct dark matter detection without assuming a restrictive high-scale supersymmetry breaking model. We find the inferred lightest CP-even Higgs boson mass as an example of an approximately prior independent observable. This analysis constitutes the first statistically convergent pMSSM global fit to all current data.

  10. Recent developments in HiggsBounds and a preview of HiggsSignals

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, Philip; Stefaniak, Tim; Williams, Karina [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). Dept. of Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver

    2013-01-15

    We report on recent developments in the public computer code HiggsBounds, which confronts arbitrary Higgs sector predictions with 95% C.L. exclusion limits from Higgs searches at the LEP, Tevatron and LHC experiments. We discuss in detail the performance of the Standard Model (SM) likeness test as implemented in the latest version HiggsBounds-3.8.0, whose outcome decides whether a search for a SM Higgs boson can be applied to a model beyond the SM. Furthermore, we give a preview of features in the upcoming version HiggsBounds-4.0.0 and the new program HiggsSignals, which performs a {chi}{sup 2} test of Higgs sector predictions against the signal rate and mass measurements from Higgs boson analyses at the Tevatron and LHC. This is illustrated with an example where the heavier CP-even Higgs boson of the Minimal Supersymmetric Standard Model (MSSM) is considered as an explanation of the LHC Higgs signal at {approx_equal} 126 GeV.

  11. Higgs Boson Searches at Hadron Colliders (1/4)

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and strategies to measured Higgs boson parameters and the investigation of alternative symmetry breaking scenarios are addressed.

  12. Academic Training Lecture: Higgs Boson Searches at Hadron Colliders

    CERN Multimedia

    HR Department

    2010-01-01

    Regular Programme 21, 22, 23 & 24 June 2010 from 11:00 to 12:00 - Main Auditorium, Bldg. 500-1-001 Higgs Boson Searches at Hadron Colliders by Dr. Karl Jakobs (University of Freiburg) In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and ...

  13. SUSY and BSM Higgs boson searches with ATLAS and CMS

    CERN Document Server

    Dasu, S

    2012-01-01

    Results of searches for super-symmetric and other beyond the Standard Model Higgs boson searches from ATLAS and CMS experiments at the LHC arc presented. Some Standard Model (SM) higgs searches are reinterpreted in SM with four quark generations and fermio­ phobic models. Stringent limits) covering a large portion of the allowed parameter space in (MA, tan/3) plane are set for MSSM neutral higgs bosons decaying to T-lepton pairs, and charged higgs boson decaying to TV. Limits are set on a light NMSSM neutral higgs boson and on doubly charged higgs bosons predicted in some models are also set.

  14. Higgs cosmology.

    Science.gov (United States)

    Rajantie, Arttu

    2018-03-06

    The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).

  15. Higgs cosmology

    Science.gov (United States)

    Rajantie, Arttu

    2018-01-01

    The discovery of the Higgs boson in 2012 and other results from the Large Hadron Collider have confirmed the standard model of particle physics as the correct theory of elementary particles and their interactions up to energies of several TeV. Remarkably, the theory may even remain valid all the way to the Planck scale of quantum gravity, and therefore it provides a solid theoretical basis for describing the early Universe. Furthermore, the Higgs field itself has unique properties that may have allowed it to play a central role in the evolution of the Universe, from inflation to cosmological phase transitions and the origin of both baryonic and dark matter, and possibly to determine its ultimate fate through the electroweak vacuum instability. These connections between particle physics and cosmology have given rise to a new and growing field of Higgs cosmology, which promises to shed new light on some of the most puzzling questions about the Universe as new data from particle physics experiments and cosmological observations become available. This article is part of the Theo Murphy meeting issue `Higgs cosmology'.

  16. Three-body decays of Higgs bosons at LEP2 and application to a hidden fermiophobic Higgs

    International Nuclear Information System (INIS)

    Akeroyd, A.G.

    1999-01-01

    We study the decays of Higgs bosons to a lighter Higgs boson and a virtual gauge boson in the context of the non-supersymmetric two-Higgs doublet model (2HDM). We consider the phenomenological impact at LEP2 and find that such decays, when open, may be dominant in regions of parameter space and thus affect current Higgs boson search techniques. Three-body decays would be a way of producing light neutral Higgs bosons which have so far escaped detection at LEP due to suppressed couplings to the Z, and are of particular importance in the 2HDM (Model I) which allows both a light fermiophobic Higgs and a light charged scalar

  17. Next-to-leading order corrections to the spin-dependent energy spectrum of hadrons from polarized top quark decay in the general two Higgs doublet model

    Directory of Open Access Journals (Sweden)

    S. Mohammad Moosavi Nejad

    2017-08-01

    Full Text Available In recent years, searches for the light and heavy charged Higgs bosons have been done by the ATLAS and the CMS collaborations at the Large Hadron Collider (LHC in proton–proton collision. Nevertheless, a definitive search is a program that still has to be carried out at the LHC. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work, we study the scaled-energy distribution of bottom-flavored mesons (B inclusively produced in polarized top quark decays into a light charged Higgs boson and a massless bottom quark at next-to-leading order in the two-Higgs-doublet model; t(↑→bH+→BH++X. This spin-dependent energy distribution is studied in a specific helicity coordinate system where the polarization vector of the top quark is measured with respect to the direction of the Higgs momentum. The study of these energy distributions could be considered as a new channel to search for the charged Higgs bosons at the LHC. For our numerical analysis and phenomenological predictions, we restrict ourselves to the unexcluded regions of the MSSM mH+−tan⁡β parameter space determined by the recent results of the CMS [13] and ATLAS [14] collaborations.

  18. The Higgs Boson.

    Science.gov (United States)

    Veltman, Martinus J. G.

    1986-01-01

    Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)

  19. The Higgs Boson as a Window to Beyond the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Morales, Roberto [Northwestern Univ., Evanston, IL (United States)

    2013-08-01

    The recent discovery of a Higgs boson at the LHC with properties resembling those predicted by the Standard Model (SM) gives strong indication that the final missing piece of the SM is now in place. In particular, the mechanism responsible for Electroweak Symmetry Breaking (EWSB) and generating masses for the Z and W vector bosons appears to have been established. Even with this amazing discovery there are still many outstanding theoretical and phenomenological questions which suggest that there must be physics Beyond the Standard Model (BSM). As we investigate in this thesis, the Higgs boson offers the exciting possibility of acting as a window to this new physics through various avenues which are experimentally testable in the coming years. We investigate a subset of these possibilities and begin by discussing them briefly below before a detailed examination in the following chapters.

  20. Higgs Mass Textures in Flipped SU(5)

    CERN Document Server

    Ellis, Jonathan Richard; Rizos, J; Ellis, John

    1999-01-01

    We analyze the Higgs doublet-triplet mass splitting problem in the version of flipped SU(5) derived from string theory. Analyzing non-renormalizable terms up to tenth order in the superpotential, we identify a pattern of field vev's that keeps one pair of electroweak Higgs doublets light, while all other Higgs doublets and all Higgs triplets are kept heavy, with the aid of the economical missing-doublet mechanism found in the field-theoretical version of flipped SU(5). The solution predicts that second-generation charge -1/3 quarks and charged leptons are much lighter than those in the third generation.

  1. Higgs Particle: The Origin of Mass

    Science.gov (United States)

    Okada, Yasuhiro

    2007-11-01

    The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics.

  2. Higgs particle. The origin of mass

    International Nuclear Information System (INIS)

    Okada, Yasuhiro

    2007-01-01

    The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments. LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics. (author)

  3. Lepton masses and mixings in orbifold models with three Higgs families

    International Nuclear Information System (INIS)

    Escudero, N.; Munoz, C.; Teixeira, A.M.

    2007-01-01

    We analyse the phenomenological viability of heterotic Z 3 orbifolds with two Wilson lines, which naturally predict three supersymmetric families of matter and Higgs fields. Given that these models can accommodate realistic scenarios for the quark sector avoiding potentially dangerous flavour-changing neutral currents, we now address the leptonic sector, finding that viable orbifold configurations can in principle be obtained. In particular, it is possible to accomodate present data on charged lepton masses, while avoiding conflict with lepton flavour-violating decays. Concerning the generation of neutrino masses and mixings, we find that Z 3 orbifolds offer several interesting possibilities

  4. The Higgs particle and higher-dimensional theories

    International Nuclear Information System (INIS)

    Lim, C. S.

    2014-01-01

    In spite of the great success of LHC experiments, we do not know whether the discovered “standard model-like” Higgs particle is really what the standard model predicts, or a particle that some new physics has in its low-energy effective theory. Also, the long-standing problems concerning the property of the Higgs and its interactions are still there, and we still do not have any conclusive argument on the origin of the Higgs itself. In this article we focus on higher-dimensional theories as new physics. First we give a brief review of their representative scenarios and closely related 4D scenarios. Among them, we mainly discuss two interesting possibilities of the origin of the Higgs: the Higgs as a gauge boson and the Higgs as a (pseudo) Nambu–Goldstone boson. Next, we argue that theories of new physics are divided into two categories, i.e., theories with normal Higgs interactions and those with anomalous Higgs interactions. Interestingly, both the candidates for the origin of the Higgs mentioned above predict characteristic “anomalous” Higgs interactions, such as the deviation of the Yukawa couplings from the standard model predictions. Such deviations can hopefully be investigated by precision tests of Higgs interactions at the planned ILC experiment. Also discussed is the main decay mode of the Higgs, H→γγ. Again, theories belonging to different categories are known to predict remarkably different new physics contributions to this important process

  5. 90 - GeV Higgs boson in supersymmetric models

    International Nuclear Information System (INIS)

    Grzadkowski, B.; Kalinowski, J.; Pokorski, S.

    1989-07-01

    We discuss supersymmetric models with a hierarchy of vacuum expectation values of Higgs fields. These models predict one of the physical neutral Higgs bosons to have its mass very close to the Z-boson mass. Properties of such a 90-GeV Higgs boson are discussed. (author)

  6. arXiv NLO predictions for Higgs boson pair production with full top quark mass dependence matched to parton showers

    CERN Document Server

    Heinrich, G.; Kerner, M.; Luisoni, G.; Vryonidou, E.

    2017-08-21

    We present the first combination of NLO QCD matrix elements for di-Higgs production, retaining the full top quark mass dependence, with a parton shower. Results are provided within both the POWHEG-BOX and MadGraph5_aMC@NLO Monte Carlo frameworks. We assess in detail the theoretical uncertainties and provide differential results. We find that, as expected, the shower effects are relatively large for observables like the transverse momentum of the Higgs boson pair, which are sensitive to extra radiation. However, these shower effects are still much smaller than the differences between the Born-improved HEFT approximation and the full NLO calculation in the tails of the distributions.

  7. The Higgs transverse momentum distribution in gluon fusion as multiscale problem

    International Nuclear Information System (INIS)

    Bagnaschi, E.; Vicini, A.

    2015-05-01

    We consider Higgs production in gluon fusion and in particular the prediction of the Higgs transverse momentum distribution. We discuss the ambiguities affecting the matching procedure between fixed order matrix elements and the resummation to all orders of the terms enhanced by log(p H T /m H ) factors. Following a recent proposal (Grazzini et al., hep-ph/1306.4581), we argue that the gluon fusion process, computed considering two active quark flavors, is a multiscale problem from the point of view of the resummation of the collinear singular terms. We perform an analysis at parton level of the collinear behavior of the real emission amplitudes and we derive an upper limit to the range of transverse momenta where the collinear approximation is valid. This scale is then used as the value of the resummation scale in the analytic resummation framework or as the value of the h parameter in the POWHEG-BOX code. Finally, we provide a phenomenological analysis in the Standard Model, in the Two Higgs Doublet Model and in the Minimal Supersymmetric Standard Model. In the two latter cases, we provide an ansatz for the central value of the matching parameters not only for a Standard Model-like Higgs boson, but also for heavy scalars and in scenarios where the bottom quark may play the dominant role.

  8. Phenomenological supersymmetry

    International Nuclear Information System (INIS)

    Zwirner, F.

    1992-01-01

    The motivations for low-energy supersymmetry and the main features of the minimal supersymmetric extension of the Standard Model are reviewed. Possible non-minimal models and the issue of gauge coupling unification are also discussed. Theoretical results relevant for supersymmetric particle searches at present and future accelerators are presented. In particular, recent results on radiative corrections to supersymmetric Higgs boson masses and couplings are summarized, and their implications for experimental searches are discussed in some detail. (author). 87 refs, 9 figs

  9. Asymptotically Free Natural Supersymmetric Twin Higgs Model

    Science.gov (United States)

    Badziak, Marcin; Harigaya, Keisuke

    2018-05-01

    Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking (EWSB). All known ultraviolet completions of TH models require some nonperturbative dynamics below the Planck scale. We propose a supersymmetric model in which the TH mechanism is introduced by a new asymptotically free gauge interaction. The model features natural EWSB for squarks and gluino heavier than 2 TeV even if supersymmetry breaking is mediated around the Planck scale, and has interesting flavor phenomenology including the top quark decay into the Higgs boson and the up quark which may be discovered at the LHC.

  10. 125 GeV Higgs boson mass from 5D gauge-Higgs unification

    Science.gov (United States)

    Carson, Jason; Okada, Nobuchika

    2018-03-01

    In the context of a simple gauge-Higgs unification (GHU) scenario based on the gauge group SU(3)×U(1)^' in a 5D flat space-time, we investigate the possibility of reproducing the observed Higgs boson mass of around 125 GeV. We introduce bulk fermion multiplets with a bulk mass and a (half-)periodic boundary condition. In our analysis, we adopt a low-energy effective theoretical approach of the GHU scenario, where the running Higgs quartic coupling is required to vanish at the compactification scale. Under this "gauge-Higgs condition," we investigate the renormalization group evolution of the Higgs quartic coupling and find a relation between the bulk mass and the compactification scale so as to reproduce the 125 GeV Higgs boson mass. Through quantum corrections at the one-loop level, the bulk fermions contribute to the Higgs boson production and decay processes and deviate the Higgs boson signal strengths at the Large Hadron Collider experiments from the Standard Model (SM) predictions. Employing the current experimental data that show that the Higgs boson signal strengths for a variety of Higgs decay modes are consistent with the SM predictions, we obtain lower mass bounds on the lightest mode of the bulk fermions to be around 1 TeV.

  11. Solving the flavour problem in supersymmetric Standard Models with three Higgs families

    International Nuclear Information System (INIS)

    Howl, R.; King, S.F.

    2010-01-01

    We show how a non-Abelian family symmetry Δ 27 can be used to solve the flavour problem of supersymmetric Standard Models containing three Higgs families such as the Exceptional Supersymmetric Standard Model (E 6 SSM). The three 27-dimensional families of the E 6 SSM, including the three families of Higgs fields, transform in a triplet representation of the Δ 27 family symmetry, allowing the family symmetry to commute with a possible high energy E 6 symmetry. The Δ 27 family symmetry here provides a high energy understanding of the Z 2 H symmetry of the E 6 SSM, which solves the flavour changing neutral current problem of the three families of Higgs fields. The main phenomenological predictions of the model are tri-bi-maximal mixing for leptons, two almost degenerate LSPs and two almost degenerate families of colour triplet D-fermions, providing a clear prediction for the LHC. In addition the model predicts PGBs with masses below the TeV scale, and possibly much lighter, which appears to be a quite general and robust prediction of all models based on the D-term vacuum alignment mechanism.

  12. Topological Higgs mechanism with ordinary Higgs mechanism

    International Nuclear Information System (INIS)

    Oda Ichiro; Yahikozawa Shigeaki.

    1989-12-01

    Topological Higgs mechanism in higher dimensions is analyzed when ordinary Higgs potential exists. It is shown that if one-form B-field becomes massive by the ordinary Higgs mechanism, another D-2 form C-field also becomes massive through topological term in addition to the topological mass generation by the topological Higgs mechanism. Moreover we investigate this mechanism in three dimensional theories, that is to say, Chern-Simons theory and more general theory. (author). 10 refs

  13. Phenomenology of unified gauge theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1983-01-01

    Part I of these lectures treats the standard Glashow-Weinberg-Salam model of weak and electromagnetic interactions, discussing in turn its basic structure and weak neutral currents, charged currents, mixing angles and CP violation, and the phenomenology of weak vector and Higgs bosons. Part II of the lectures discusses the structure of theories of dynamical symmetry breaking such as technicolour, phenomenological consequences, frustrations and alternatives. The third part of these lectures offers the standard menu of grand unified theories (GUTs) of the strong, weak and electromagnetic interactions, including an hors d'oeuvre of constraints on the parameters of the standard model, a main course of baryon number violating processes, and desserts which violate lepton number and CP. The fourth and final part goes through different attempts to remedy the inadequacies of previous theories by invoking supersymmetry and reaching out towards gravitation. (orig./HSI)

  14. Updated Higgs cross section at approximate N3LO

    International Nuclear Information System (INIS)

    Bonvini, Marco; Ball, Richard D; Forte, Stefano; Marzani, Simone; Ridolfi, Giovanni

    2014-01-01

    We update our estimate of the cross section for Higgs production in gluon fusion at next-to-next-to-next-to-leading order in α s in view of the recent full computation of the result in the soft limit for infinite top mass, which determines a previously unknown constant. We briefly discuss the phenomenological implications. Results are available through the updated version of the ggHiggs code. (paper)

  15. Updated Higgs cross section at approximate N3LO

    International Nuclear Information System (INIS)

    Bonvini, Marco; Ball, Richard D.; Marzani, Simone

    2014-04-01

    We update our estimate of the cross section for Higgs production in gluon fusion at next-to-next-to-next-to-leading order (N 3 LO) in α s in view of the recent full computation of the result in the soft limit for infinite top mass, which determines a previously unknown constant. We briefly discuss the phenomenological implications. Results are available through the updated version of the ggHiggs code.

  16. The spontaneous ℤ_2 breaking Twin Higgs

    International Nuclear Information System (INIS)

    Beauchesne, Hugues; Earl, Kevin; Grégoire, Thomas

    2016-01-01

    The Twin Higgs model seeks to address the little hierarchy problem by making the Higgs a pseudo-Goldstone of a global SU(4) symmetry that is spontaneously broken to SU(3). Gauge and Yukawa couplings, which explicitly break SU(4), enjoy a discrete ℤ_2 symmetry that accidentally maintains SU(4) at the quadratic level and therefore keeps the Higgs light. Contrary to most beyond the Standard Model theories, the quadratically divergent corrections to the Higgs mass are cancelled by a mirror sector, which is uncharged under the Standard Model groups. However, the Twin Higgs with an exact ℤ_2 symmetry leads to equal vevs in the Standard Model and mirror sectors, which is phenomenologically unviable. An explicit ℤ_2 breaking potential must then be introduced and tuned against the SU(4) breaking terms to produce a hierarchy of vevs between the two sectors. This leads to a moderate but non-negligible tuning. We propose a model to alleviate this tuning, without the need for an explicit ℤ_2 breaking sector. The model consists of two SU(4) fundamental Higgses, one whose vacuum preserves ℤ_2 and one whose vacuum breaks it. As the interactions between the two Higgses are turned on, the ℤ_2 breaking is transmitted from the broken to the unbroken sector and a small hierarchy of vevs is naturally produced. The presence of an effective tadpole and feedback between the two Higgses lead to a sizable improvement of the tuning. The resulting Higgs boson is naturally very Standard Model like.

  17. Smoking-gun signatures of little Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Han Tao [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Institute of Theoretical Physics, Academia Sinica, Beijing 100080 (China); Logan, Heather E. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Wang, L.-T. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Jefferson Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2006-01-15

    Little Higgs models predict new gauge bosons, fermions and scalars at the TeV scale that stabilize the Higgs mass against quadratically divergent one-loop radiative corrections. We categorize the many little Higgs models into two classes based on the structure of the extended electroweak gauge group and examine the experimental signatures that identify the little Higgs mechanism in addition to those that identify the particular little Higgs model. We find that by examining the properties of the new heavy fermion(s) at the LHC, one can distinguish the structure of the top quark mass generation mechanism and test the little Higgs mechanism in the top sector. Similarly, by studying the couplings of the new gauge bosons to the light Higgs boson and to the Standard Model fermions, one can confirm the little Higgs mechanism and determine the structure of the extended electroweak gauge group.

  18. QCD phenomenology

    International Nuclear Information System (INIS)

    Gaillard, M.K.

    1979-01-01

    Selected topics in QCD phenomenology are reviewed: the development of an effective jet perturbation series with applications to factorization, energy flow analysis and photon physics; implications of non-perturbative phenomena for hard scattering processes and the pseudoscalar mass spectrum; resonance properties as extracted from the combined technologies of perturbative and non-perturbative QCD. (orig.)

  19. String phenomenology

    CERN Document Server

    Ibáñez, Luis E

    2015-01-01

    This chapter reviews a number of topics in the field of string phenomenology, focusing on orientifold/F-theory models yielding semirealistic low-energy physics. The emphasis is on the extraction of the low-energy effective action and possible tests of specific models at the LHC.

  20. Higgs physics at LHC

    OpenAIRE

    Unal, G

    2006-01-01

    This is a review of Higgs physics at LHC. The topics covered are the search of the Standard Model Higgs boson (with emphasis on the low mass region), the measurements of the Higgs boson properties (mass, width, spin, CP and couplings) and the Higgs sector of the MSSM.

  1. Corrections to di-Higgs boson production with light stops and modified Higgs couplings

    Science.gov (United States)

    Huang, Peisi; Joglekar, Aniket; Li, Min; Wagner, Carlos E. M.

    2018-04-01

    The Higgs pair production in gluon fusion is a sensitive probe of beyond-standard model (BSM) phenomena and its detection is a major goal for the LHC and higher energy hadron collider experiments. In this work we reanalyze the possible modifications of the Higgs pair production cross section within low energy supersymmetry models. We show that the supersymmetric contributions to the Higgs pair production cross section are strongly correlated with the ones of the single Higgs production in the gluon fusion channel. Motivated by the analysis of ATLAS and CMS Higgs production data, we show that the scalar superpartners' contributions may lead to significant modification of the di-Higgs production rate and invariant mass distribution with respect to the SM predictions. We also analyze the combined effects on the di-Higgs production rate of a modification of the Higgs trilinear and top-quark Yukawa couplings in the presence of light stops. In particular, we show that due to the destructive interference of the triangle and box amplitude contributions to the di-Higgs production cross section, even a small modification of the top-quark Yukawa coupling can lead to a significant increase of the di-Higgs production rate.

  2. Higgs and supersymmetry

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, O. [Imperial College, London (United Kingdom). High Energy Physics Group; Cavanaugh, R. [Fermi National Accelerator Laboratory, Batavia, IL (United States); Illinois Univ, Chicago, IL (United States). Physics Dept.; Roeck, A. de [CERN, Geneva (Switzerland); Antwerp Univ., Wilrijk (BE)] (and others)

    2011-12-15

    Global frequentist fits to the CMSSM and NUHM1 using the MasterCode framework predicted M{sub h}{approx_equal}119 GeV in fits incorporating the (g-2){mu} constraint and {approx_equal}126 GeV without it. Recent results by ATLAS and CMS could be compatible with a Standard Model-like Higgs boson around M{sub h}{approx_equal}125 GeV. We use the previous MasterCode analysis to calculate the likelihood for a measurement of any nominal Higgs mass within the range of 115 to 130 GeV. Assuming a Higgs mass measurement at M{sub h}{approx_equal}125 GeV, we display updated global likelihood contours in the (m{sub 0},m{sub 1/2}) and other parameter planes of the CMSSM and NUHM1, and present updated likelihood functions for m{sub g}, m{sub q{sub R}}, BR(B{sub s} {yields} {mu}{sup +}{mu}{sup -}) and the spin-independent dark matter cross section {sigma}{sup SI}{sub p}. The implications of dropping (g-2){sub {mu}} from the fits are also discussed. We furthermore comment on a hypothetical measurement of M{sub h}{approx_equal}119 GeV. (orig.)

  3. Likely values of the Higgs vacuum expectation value

    International Nuclear Information System (INIS)

    Donoghue, John F.; Dutta, Koushik; Ross, Andreas; Tegmark, Max

    2010-01-01

    We make an estimate of the likelihood function for the Higgs vacuum expectation value (vev) by imposing anthropic constraints on the existence of atoms while allowing the other parameters of the standard model to also be variable. We argue that the most important extra ingredients are the Yukawa couplings, and for the intrinsic distribution of Yukawa couplings we use the scale-invariant distribution which is favored phenomenologically. The result is successful phenomenologically, favoring values close to the observed vev. We also discuss modifications that can change these conclusions. Our work supports the hypothesis that the anthropic constraints could be the origin of the small Higgs vev.

  4. Higgs results from ATLAS

    International Nuclear Information System (INIS)

    Chen, Xin

    2016-01-01

    The updated Higgs measurements in various search channels with ATLAS Run 1 data are reviewed. Both the Standard Model (SM) Higgs results, such as H → γγ, ZZ, WW, ττ, μμ, bb-bar, and Beyond Standard Model (BSM) results, such as the charged Higgs, Higgs invisible decay and tensor couplings, are summarized. Prospects for future Higgs searches are briefly discussed

  5. Threshold region for Higgs boson production in gluon fusion.

    Science.gov (United States)

    Bonvini, Marco; Forte, Stefano; Ridolfi, Giovanni

    2012-09-07

    We provide a quantitative determination of the effective partonic kinematics for Higgs boson production in gluon fusion in terms of the collider energy at the LHC. We use the result to assess, as a function of the Higgs boson mass, whether the large m(t) approximation is adequate and Sudakov resummation advantageous. We argue that our results hold to all perturbative orders. Based on our results, we conclude that the full inclusion of finite top mass corrections is likely to be important for accurate phenomenology for a light Higgs boson with m(H)~125 GeV at the LHC with √s=14 TeV.

  6. Thermal leptogenesis in a supersymmetric neutrinophilic Higgs model

    International Nuclear Information System (INIS)

    Haba, Naoyuki; Seto, Osamu

    2011-01-01

    We investigate thermal leptogenesis in a supersymmetric neutrinophilic Higgs model by taking phenomenological constraints into account, where, in addition to the minimal supersymmetric standard model, we introduce an extra Higgs field with a tiny vacuum expectation value which generates neutrino masses. Thanks to this tiny vacuum expectation value of the neutrinophilic Higgs, our model allows us to reduce the mass of the lightest right-handed (s)neutrino to be O(10 5 ) GeV, keeping sufficiently large CP asymmetry in its decay. Therefore, the reheating temperature after inflation is not necessarily high; hence this scenario is free from the gravitino problem.

  7. CP violation in supersymmetry, Higgs sector and large hadron collider

    International Nuclear Information System (INIS)

    Godbole, Rohini M.

    2006-01-01

    In this talk I discuss some aspects of CP violation (CPV) in supersymmetry (SUSY) as well as in the Higgs sector. Further, I discuss ways in which these may be probed at hadronic colliders. In particular I will point out the ways in which studies in the χ ∼± , χ 2 ∼0 sector at Tevatron may be used to provide information on this and how the search can be extended to the LHC. I will then follow this by a discussion of the CP mixing induced in the Higgs sector due to the above-mentioned CPV in the soft SUSY breaking parameters and its effects on the Higgs phenomenology at the LHC. I would then point out some interesting aspects of the phenomenology of a moderately light charged Higgs boson, consistent with the LEP constraints, in this scenario. Decay of such a charged Higgs boson would also allow a probe of a light (≤)50 GeV), CP-violating (CPV) Higgs boson. Such a light neutral Higgs boson might have escaped detection at LEP and could also be missed at the LHC in the usual search channels. (author)

  8. Higgs boson from an extended symmetry

    International Nuclear Information System (INIS)

    Barbieri, Riccardo; Bellazzini, Brando; Rychkov, Vyacheslav S.; Varagnolo, Alvise

    2007-01-01

    The variety of ideas put forward in the context of a composite picture for the Higgs boson calls for a simple and effective description of the related phenomenology. Such a description is given here by means of a minimal model and is explicitly applied to the example of a Higgs-top sector from an SO(5) symmetry. We discuss the spectrum, the electroweak precision tests, B-physics, and naturalness. We show the difficulty in complying with the different constraints. The extended gauge sector relative to the standard SU(2)xU(1), if there is any, has little or no impact on these considerations. We also discuss the relation of the minimal model with its 'little Higgs' or holographic extensions based on the same symmetry

  9. Phenomenology & Sociality

    DEFF Research Database (Denmark)

    Gahrn-Andersen, Rasmus; Cowley, Stephen

    2017-01-01

    Although cognitive science has recently asked how human sociality is constituted, there is no clear and consistent account of the emergence of human style social agency. Previously, we have critiqued views based on 'participatory sense-making' by arguing that agency requires a distinctive kind...... of phenomenology that enables a diachronic social experience. In advancing the positive argument, we link developmental psychology to phenomenological insights by focusing on child-caregiver dynamics around the middle of the second year. Having developed very basic social skills, an infant comes to feel normative....... Developmental events thus transform the child's experience and drive the emergence of social agency. Once the child has successfully dealt with the environment’s normative perturbations she is able to develop the skills of a fully-fledged human social agent....

  10. Towards a unified picture for gauge and Higgs fields

    International Nuclear Information System (INIS)

    Mecklenburg, W.

    1981-01-01

    A scheme for a geometrical unification of gauge and Higgs fields, previously given for SU 2 , is generalized to include arbitrary semisimple gauge groups. Gauge and physical Higgs fields appear as different components of the same tensor in a high dimensional manifold, the higher dimensions being comprised by the group coordinates. Their respective inhomogeneous transformation behaviour is derived from the same principle. The number of Higgs fields is restricted. The form of the Higgs potential is fixed and the mass of the Higgs particle is predicted in terms of the vector boson mass. (author)

  11. Prospects for Higgs search at D

    Indian Academy of Sciences (India)

    - terize the Higgs sector of the standard model. The minimal version of the standard model requires a single scalar particle, though many extensions predict additional particles. Fits to the global set of electroweak data provide an indirect upper ...

  12. Character Profile of the Higgs boson

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00386479; Bentvelsen, Stan; Ferrari, Pamela

    Elementary particle physics describes and measures the properties of the smallest, most fundamental particles that make up the universe. The Standard Model of elementary particle physics provides a fundamental description of particles, their dynamics and interactions. The particles embedded into the theory are, a priori, massless, while observed particles have mass. In order to explain the origin of the elementary particle masses, the Brout-Englert-Higgs mechanism is introduced. The mechanism introduces the existence of one real scalar field, with the Higgs boson as excitation, however it does not predict its mass. To verify that the Higgs mechanism is the origin of elementary particle masses is one of the main goals of the Large Hadron Collider (LHC) programs at CERN. Higgs physics at the ATLAS detector has reached an exciting new phase of precision measurements, but the analyses are still mostly set up for conducting searches. The research shown in this thesis has provided measurements in the Higgs sector, ...

  13. ILC Higgs White Paper

    CERN Document Server

    Asner, D.M.; Calancha, C.; Fujii, K.; Graf, N.; Haber, H.E.; Ishikawa, A.; Kanemura, S.; Kawada, S.; Kurata, M.; Miyamoto, A.; Neal, H.; Ono, H.; Potter, C.; Strube, J.; Suehara, T.; Tanabe, T.; Tian, J.; Tsumura, J.; Watanuki, S.; Weiglein, G.; Yagyu, K.; Yokoya, H.

    2013-01-01

    The ILC Higgs White Paper is a review of Higgs Boson theory and experiment at the International Linear Collider (ILC). Theory topics include the Standard Model Higgs, the two-Higgs doublet model, alternative approaches to electroweak symmetry breaking, and precision goals for Higgs boson experiments. Experimental topics include the measurement of the Higgs cross section times branching ratio for various Higgs decay modes at ILC center of mass energies of 250, 500, and 1000 GeV, and the extraction of Higgs couplings and the total Higgs width from these measurements. Luminosity scenarios based on the ILC TDR machine design are used throughout. The gamma-gamma collider option at the ILC is also discussed.

  14. CMS Higgs boson results

    CERN Document Server

    Bluj, Michal Jacek

    2018-01-01

    In this report we review recent Higgs boson results obtained with pp collisions at $\\sqrt{s}=\\,$13 TeV recorded by the CMS detector in 2016 for an integrated luminosity of 35.9fb$^{\\text{-1}}$. The 2016 data allowed the observation of the $H \\to \\tau\\tau$ and $H \\to WW$ decays with high significance. We also present a combined measurement based on a full set of CMS analyses performed with 2016 data. These results are compatible with the standard model predictions with precision of several measurements exceeding results from combination of ATLAS and CMS data collected in 2011 and 2012.

  15. Semialigned two Higgs doublet model

    Science.gov (United States)

    Haba, Naoyuki; Umeeda, Hiroyuki; Yamada, Toshifumi

    2018-02-01

    In the left-right symmetric model based on S U (2 )L×S U (2 )R×U (1 )B -L gauge symmetry, there appear heavy neutral scalar particles mediating quark flavor changing neutral currents (FCNCs) at tree level. We consider a situation where such FCNCs give the only sign of the left-right model while WR gauge boson is decoupled, and name it "semialigned two Higgs doublet model" because the model resembles a two Higgs doublet model with mildly aligned Yukawa couplings to quarks. We predict a correlation among processes induced by quark FCNCs in the model, and argue that future precise calculation of meson-antimeson mixings and C P violation therein may hint at the semialigned two Higgs doublet model and the left-right model behind it.

  16. Top and Higgs mass predictions in supersymmetric SU(5) model with big top quark Yukawa coupling constant

    International Nuclear Information System (INIS)

    Krasnikov, N.V.; Rodenberg, R.

    1993-01-01

    From the requirement of the absence of the Landau pole singularity for the effective top quark Yukawa coupling constant up to Planck scale in SU(5) supersymmetric model we find an upper bound m t ≤ 187 GeV for the top quark mass. For the SU(5) fixed point renormalization group solution for top quark Yukawa coupling constant which can be interpreted as the case of composite superhiggs we find that m t ≥ 140 GeV. Similar bound takes place in all models with big anti h t (m t ). For m t ≤ 160 GeV we find also that the Higgs boson is lighter than m Z and hence it can be discovered at LEP2

  17. Finding the CP-violating Higgs bosons at e+e- colliders

    International Nuclear Information System (INIS)

    Grzadkowski, B.; Gunion, J.F.; Kalinowski, J.

    1999-01-01

    We discuss a general two-Higgs-doublet model with CP violation in the Higgs sector. In general, the three neutral Higgs fields of the model all mix and the resulting physical Higgs bosons have no definite CP properties. We derive a new sum rule relating Yukawa and Higgs-Z couplings which implies that a neutral Higgs boson cannot escape detection at an e + e - collider if it is kinematically accessible in Z+Higgs boson, b bar b+Higgs boson and t bar t+Higgs boson production, irrespective of the mixing angles and the masses of the other neutral Higgs bosons. We also discuss modifications of the sum rules and their phenomenological consequences in the case when the two-doublet Higgs sector is extended by adding one or more singlets. A brief discussion of the implications of the sum rules for Higgs boson discovery at the Fermilab Tevatron and CERN LHC is given. copyright 1999 The American Physical Society

  18. Phenomenology of Compositeness at the LHC

    CERN Document Server

    Salvioni, Ennio; Zwirner, Fabio

    The hierarchy problem of the weak scale calls for extensions of the Standard Model at the TeV, and thus within the reach of the CERN Large Hadron Collider (LHC). One of the best motivated proposals builds on the idea that the Higgs could be a composite pseudo-Nambu-Goldstone boson. In this thesis we discuss several topics in the phenomenology of composite Higgs models, concentrating mainly on LHC physics. In Chapter 1 we introduce the hierarchy problem and the essential features of viable theories of compositeness at the TeV scale. Chapter 2 is dedicated to a review of concrete constructions realizing the composite Higgs idea, focusing mostly on models with partial compositeness. In Chapter 3 we present the effective Lagrangians suited for describing the Higgs boson and the constraints placed by electroweak precision tests on their parameters. Motivated by hints in the experimental results, we also reconsider the possibility of custodial breaking in the couplings of the Higgs to the W and Z. Chapter 4 is devo...

  19. New ideas for effective Higgs measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brehmer, Johann

    2017-07-26

    An effective field theory provides a model-independent and phenomenologically powerful parametrisation of new physics in the Higgs sector. We analyse two aspects of this framework that are relevant for measurements of the Higgs properties during Run 2 of the LHC. First, the limited precision of the LHC analyses cannot guarantee a clear hierarchy between the experimental momentum transfer and the probed new physics scales, casting doubt on the validity of the effective model. By comparing a range of new physics scenarios to their dimension-six approximation, we analyse if an effective description of the Higgs sector is useful, where it breaks down, and how its validity can be improved. Second, we use information geometry to understand and optimise Higgs measurements at the LHC. Our novel approach is based on the Fisher information, which encodes the maximum precision with which theory parameters can be measured in an experiment. We develop an algorithm to calculate the Fisher information in LHC processes and compute the information on dimension-six operators in different Higgs signatures. We demonstrate how information geometry lets us improve event selections, determine the most powerful observables, and compare the power of modern multivariate techniques to that of traditional histogram-based analyses.

  20. New ideas for effective Higgs measurements

    International Nuclear Information System (INIS)

    Brehmer, Johann

    2017-01-01

    An effective field theory provides a model-independent and phenomenologically powerful parametrisation of new physics in the Higgs sector. We analyse two aspects of this framework that are relevant for measurements of the Higgs properties during Run 2 of the LHC. First, the limited precision of the LHC analyses cannot guarantee a clear hierarchy between the experimental momentum transfer and the probed new physics scales, casting doubt on the validity of the effective model. By comparing a range of new physics scenarios to their dimension-six approximation, we analyse if an effective description of the Higgs sector is useful, where it breaks down, and how its validity can be improved. Second, we use information geometry to understand and optimise Higgs measurements at the LHC. Our novel approach is based on the Fisher information, which encodes the maximum precision with which theory parameters can be measured in an experiment. We develop an algorithm to calculate the Fisher information in LHC processes and compute the information on dimension-six operators in different Higgs signatures. We demonstrate how information geometry lets us improve event selections, determine the most powerful observables, and compare the power of modern multivariate techniques to that of traditional histogram-based analyses.

  1. A comparison of the Higgs sectors of the CMSSM and NMSSM for a 126 GeV Higgs boson

    International Nuclear Information System (INIS)

    Beskidt, C.; Boer, W. de; Kazakov, D.I.

    2013-01-01

    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 χ 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 radiative corrections are needed to obtain a Higgs boson mass of 126 GeV, which requires stop squark masses in the multi-TeV range. In contrast, for the NMSSM light stop quarks are allowed, since in the NMSSM at tree level the Higgs boson mass can be above the Z 0 boson mass from mixing with the additional singlet Higgs boson. Predictions for the scalar boson masses are given in both models with emphasis on the unique signatures of the NMSSM, where the heaviest scalar Higgs boson decays in the two lighter scalar Higgs bosons with a significant branching ratio, in which case one should observe double Higgs boson production at the LHC. Such a signal is strongly suppressed in the CMSSM. In addition, since the LSP is higgsino-like, Higgs boson decays into LSPs can be appreciable, thus leading to invisible Higgs decays

  2. Higgs Physics and Cosmology

    Science.gov (United States)

    Roberts, Alex

    2016-08-01

    Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. We elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein. We explore supersymmetric theories in which the Higgs mass is boosted by the non-decoupling D-terms of an extended U(1) X gauge symmetry, defined here to be a general linear combination of hypercharge, baryon number, and lepton number. Crucially, the gauge coupling, gX, is bounded from below to accommodate the Higgs mass, while the quarks and leptons are required by gauge invariance to carry non-zero charge under U(1)X. This induces an irreducible rate, sigmaBR, for pp → X → ll relevant to existing and future resonance searches, and gives rise to higher dimension operators that are stringently constrained by precision electroweak measurements. Combined, these bounds define a maximally allowed region in the space of observables, (sigmaBR, mX), outside of which is excluded by naturalness and experimental limits. If natural supersymmetry utilizes non-decoupling D-terms, then the associated X boson can only be observed within this window, providing a model independent 'litmus test' for this broad

  3. Perspectives on string phenomenology

    CERN Document Server

    Kane, Gordon; Kumar, Piyush

    2015-01-01

    The remarkable recent discovery of the Higgs boson at the CERN Large Hadron Collider completed the Standard Model of particle physics and has paved the way for understanding the physics which may lie beyond it. String/M theory has emerged as a broad framework for describing a plethora of diverse physical systems, which includes condensed matter systems, gravitational systems as well as elementary particle physics interactions. If string/M theory is to be considered as a candidate theory of Nature, it must contain an effectively four-dimensional universe among its solutions that is indistinguishable from our own. In these solutions, the extra dimensions of string/M Theory are “compactified” on tiny scales which are often comparable to the Planck length. String phenomenology is the branch of string/M theory that studies such solutions, relates their properties to data, and aims to answer many of the outstanding questions of particle physics beyond the Standard Model. This book contains perspectives on stri...

  4. The U(1) Higgs model in an external electromagnetic field

    International Nuclear Information System (INIS)

    Damgaard, P.H.; Heller, U.M.

    1988-01-01

    An external electromagnetic field is coupled to the lattice-regularized U(1) Higgs model. We study the phase diagram of this model by both analytical and numerical techniques for different values of the external field strength tensor. The results are compared with expectations based on the analogy with superconducting systems, as described by the phenomenological Ginzburg-Landau theory. (orig.)

  5. Improving the discovery potential of charged Higgs bosons at the ...

    Indian Academy of Sciences (India)

    The Run 2 discovery potential of H¦bosons in a general Type-II 2HDM is ... gluon and quark–antiquark pairs (hence – by definition – the attainable Higgs ... This description fails to correctly account for the production phenomenology of charged.

  6. Higgs physics at CMS

    Energy Technology Data Exchange (ETDEWEB)

    Holzner, André G., E-mail: andre.georg.holzner@cern.ch [University of California at San Diego (United States); Collaboration: on behalf of the CMS collaboration

    2016-12-15

    This article reviews recent measurements of the properties of the standard model (SM) Higgs boson using data recorded with the CMS detector at the LHC: its mass, width and couplings to other SM particles. We also summarise highlights from searches for new physical phenomena in the Higgs sector as they are proposed in many extensions of the SM: flavour violating and invisible decay modes, resonances decaying into Higgs bosons and searches for additional Higgs bosons.

  7. Future ATLAS Higgs Studies

    CERN Document Server

    Smart, Ben; The ATLAS collaboration

    2017-01-01

    The High-Luminosity LHC will prove a challenging environment to work in, with for example $=200$ expected. It will however also provide great opportunities for advancing studies of the Higgs boson. The ATLAS detector will be upgraded, and Higgs prospects analyses have been performed to assess the reach of ATLAS Higgs studies in the HL-LHC era. These analyses are presented, as are Run-2 ATLAS di-Higgs analyses for comparison.

  8. Higgs-boson production and decay close to thresholds

    International Nuclear Information System (INIS)

    Kniehl, B.A.; Palisoc, C.P.; Sirlin, A.; New York Univ., NY

    2000-07-01

    At one loop in the conventional on-mass-shell renormalization scheme, the production and decay rates of the Higgs boson H exhibit singularities proportional to (2M V -M) -1/2 as the Higgs-boson mass M approaches from below the pair-production threshold of a vector boson V with mass M V . This problem is of phenomenological interest because the values 2M W and 2M Z , corresponding to the W- and Z-boson thresholds, lie within the M range presently favoured by electroweak precision data. We demonstrate how these threshold singularities are eliminated when the definitions of mass and total decay width of the Higgs boson are based on the complex-valued pole of its propagator. We illustrate the phenomenological implications of this modification for the partial width of the H → W + W - decay. (orig.)

  9. Higgs-boson production and decay close to thresholds

    International Nuclear Information System (INIS)

    Kniehl, Bernd A.; Palisoc, Caesar P.; Sirlin, Alberto

    2000-01-01

    At one loop in the conventional on-mass-shell renormalization scheme, the production and decay rates of the Higgs-boson H exhibit singularities proportional to (2M V -M) -1/2 as the Higgs-boson mass M approaches from below the pair-production threshold of a vector boson V with mass M V . This problem is of phenomenological interest because the values 2M W and 2M Z , corresponding to the W- and Z-boson thresholds, lie within the M range presently favoured by electroweak precision data. We demonstrate how these threshold singularities are eliminated when the definitions of mass and total decay width of the Higgs-boson are based on the complex-valued pole of its propagator. We illustrate the phenomenological implications of this modification for the partial width of the H→W + W - decay

  10. Higgs boson decays and production via gluon fusion at LHC in littlest Higgs models with T parity

    International Nuclear Information System (INIS)

    Wang Lei; Yang Jinmin

    2009-01-01

    We study the Higgs boson decays and production via gluon fusion at the LHC as a probe of two typical littlest Higgs models which introduce a top quark partner with different (even and odd) T parity to cancel the Higgs mass quadratic divergence contributed by the top quark. For each model, we consider two different choices for the down-type quark Yukawa couplings. We first examine the branching ratios of the Higgs boson decays and then study the production via gluon fusion followed by the decay into two photons or two weak gauge bosons. We find that the predictions can be quite different for different models or different choices of down-type quark Yukawa couplings, and all these predictions can sizably deviate from the standard model predictions. So the Higgs boson processes at the LHC can be a sensitive probe for these littlest Higgs models.

  11. The Higgs hunter's guide

    CERN Document Server

    Gunion, John F; Haber, Howard E; Kane, Gordon L

    1989-01-01

    The Higgs Hunter's Guide is a definitive and comprehensive guide to the physics of Higgs bosons. In particular, it discusses the extended Higgs sectors required by those recent theoretical approaches that go beyond the Standard Model, including supersymmetry and superstring-inspired models.

  12. Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A. [Yerevan Physics Institute, Yerevan (Armenia); Collaboration: The CMS Collaboration; and others

    2015-05-15

    Properties of the Higgs boson with mass near 125 GeV are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include γγ, ZZ, WW, ττ, bb, and μμ pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1 fb{sup -1} at 7 TeV and up to 19.7 fb{sup -1} at 8 TeV. From the high-resolution γγ and ZZ channels, the mass of the Higgs boson is determined to be 125.02{sub -0.27}{sup +0.26}(stat){sub -0.15}{sup +0.14}(syst) GeV. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is 1.00 ±0.09(stat){sub -0.07}{sup +0.08}(theo) ±0.07 (syst) at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found. (orig.)

  13. Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV

    International Nuclear Information System (INIS)

    Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.

    2015-01-01

    Properties of the Higgs boson with mass near 125 GeV are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include γγ, ZZ, WW, ττ, bb, and μμ pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1 fb -1 at 7 TeV and up to 19.7 fb -1 at 8 TeV. From the high-resolution γγ and ZZ channels, the mass of the Higgs boson is determined to be 125.02 -0.27 +0.26 (stat) -0.15 +0.14 (syst) GeV. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is 1.00 ±0.09(stat) -0.07 +0.08 (theo) ±0.07 (syst) at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found. (orig.)

  14. Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8[Formula: see text].

    Science.gov (United States)

    Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hartl, C; Hörmann, N; Hrubec, J; Jeitler, M; Kiesenhofer, W; Knünz, V; Krammer, M; Krätschmer, I; Liko, D; Mikulec, I; Rabady, D; Rahbaran, B; Rohringer, H; Schöfbeck, R; Strauss, J; Treberer-Treberspurg, W; Waltenberger, W; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Alderweireldt, S; Bansal, S; Cornelis, T; De Wolf, E A; Janssen, X; Knutsson, A; Lauwers, J; Luyckx, S; Ochesanu, S; Rougny, R; Van De Klundert, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Van Spilbeeck, A; Blekman, F; Blyweert, S; D'Hondt, J; Daci, N; Heracleous, N; Keaveney, J; Lowette, S; Maes, M; Olbrechts, A; Python, Q; Strom, D; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Caillol, C; Clerbaux, B; De Lentdecker, G; Dobur, D; Favart, L; Gay, A P R; Grebenyuk, A; Léonard, A; Mohammadi, A; Perniè, L; Randle-Conde, A; Reis, T; Seva, T; Thomas, L; Vander Velde, C; Vanlaer, P; Wang, J; Zenoni, F; Adler, V; Beernaert, K; Benucci, L; Cimmino, A; Costantini, S; Crucy, S; Fagot, A; Garcia, G; Mccartin, J; Ocampo Rios, A A; Poyraz, D; Ryckbosch, D; Salva Diblen, S; Sigamani, M; Strobbe, N; Thyssen, F; Tytgat, M; Yazgan, E; Zaganidis, N; Basegmez, S; Beluffi, C; Bruno, G; Castello, R; Caudron, A; Ceard, L; Da Silveira, G G; Delaere, C; du Pree, T; Favart, D; Forthomme, L; Giammanco, A; Hollar, J; Jafari, A; Jez, P; Komm, M; Lemaitre, V; Nuttens, C; Pagano, D; Perrini, L; Pin, A; Piotrzkowski, K; Popov, A; Quertenmont, L; Selvaggi, M; Vidal Marono, M; Vizan Garcia, J M; Beliy, N; Caebergs, T; Daubie, E; Hammad, G H; Júnior, W L Aldá; Alves, G A; Brito, L; Correa Martins Junior, M; Martins, T Dos Reis; Molina, J; Mora Herrera, C; Pol, M E; Teles, P Rebello; Carvalho, W; Chinellato, J; Custódio, A; Da Costa, E M; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Malbouisson, H; Matos Figueiredo, D; Mundim, L; Nogima, H; Prado Da Silva, W L; Santaolalla, J; Santoro, A; Sznajder, A; Tonelli Manganote, E J; Vilela Pereira, A; Bernardes, C A; Dogra, S; Fernandez Perez Tomei, T R; Gregores, E M; Mercadante, P G; Novaes, S F; Padula, Sandra S; Aleksandrov, A; Genchev, V; Hadjiiska, R; Iaydjiev, P; Marinov, A; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Vutova, M; Dimitrov, A; Glushkov, I; Litov, L; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Chen, M; Cheng, T; Du, R; Jiang, C H; Plestina, R; Romeo, F; Tao, J; Wang, Z; Asawatangtrakuldee, C; Ban, Y; Liu, S; Mao, Y; Qian, S J; Wang, D; Xu, Z; Zhang, F; Zhang, L; Zou, W; Avila, C; Cabrera, A; Chaparro Sierra, L F; Florez, C; Gomez, J P; Gomez Moreno, B; Sanabria, J C; Godinovic, N; Lelas, D; Polic, D; Puljak, I; Antunovic, Z; Kovac, M; Brigljevic, V; Kadija, K; Luetic, J; Mekterovic, D; Sudic, L; Attikis, A; Mavromanolakis, G; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Rykaczewski, H; Bodlak, M; Finger, M; Finger, M; Assran, Y; Ellithi Kame, A; Mahmoud, M A; Radi, A; Kadastik, M; Murumaa, M; Raidal, M; Tiko, A; Eerola, P; Voutilainen, M; Härkönen, J; Heikkilä, J K; Karimäki, V; Kinnunen, R; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Peltola, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Wendland, L; Talvitie, J; Tuuva, T; Besancon, M; Couderc, F; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Favaro, C; Ferri, F; Ganjour, S; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Malcles, J; Rander, J; Rosowsky, A; Titov, M; Baffioni, S; Beaudette, F; Busson, P; Chapon, E; Charlot, C; Dahms, T; Dobrzynski, L; Filipovic, N; Florent, A; Granier de Cassagnac, R; Mastrolorenzo, L; Miné, P; Naranjo, I N; Nguyen, M; Ochando, C; Ortona, G; Paganini, P; Regnard, S; Salerno, R; Sauvan, J B; Sirois, Y; Veelken, C; Yilmaz, Y; Zabi, A; Agram, J-L; Andrea, J; Aubin, A; Bloch, D; Brom, J-M; Chabert, E C; Collard, C; Conte, E; Fontaine, J-C; Gelé, D; Goerlach, U; Goetzmann, C; Le Bihan, A-C; Skovpen, K; Van Hove, P; Gadrat, S; Beauceron, S; Beaupere, N; Bernet, C; Boudoul, G; Bouvier, E; Brochet, S; Carrillo Montoya, C A; Chasserat, J; Chierici, R; Contardo, D; Courbon, B; Depasse, P; El Mamouni, H; Fan, J; Fay, J; Gascon, S; Gouzevitch, M; Ille, B; Kurca, T; Lethuillier, M; Mirabito, L; Pequegnot, A L; Perries, S; Ruiz Alvarez, J D; Sabes, D; Sgandurra, L; Sordini, V; Vander Donckt, M; Verdier, P; Viret, S; Xiao, H; Tsamalaidze, Z; Autermann, C; Beranek, S; Bontenackels, M; Edelhoff, M; Feld, L; Heister, A; Klein, K; Lipinski, M; Ostapchuk, A; Preuten, M; Raupach, F; Sammet, J; Schael, S; Schulte, J F; Weber, H; Wittmer, B; Zhukov, V; Ata, M; Brodski, M; Dietz-Laursonn, E; Duchardt, D; Erdmann, M; Fischer, R; Güth, A; Hebbeker, T; Heidemann, C; Hoepfner, K; Klingebiel, D; Knutzen, S; Kreuzer, P; Merschmeyer, M; Meyer, A; Millet, P; Olschewski, M; Padeken, K; Papacz, P; Reithler, H; Schmitz, S A; Sonnenschein, L; Teyssier, D; Thüer, S; Cherepanov, V; Erdogan, Y; Flügge, G; Geenen, H; Geisler, M; Haj Ahmad, W; Hoehle, F; Kargoll, B; Kress, T; Kuessel, Y; Künsken, A; Lingemann, J; Nowack, A; Nugent, I M; Pistone, C; Pooth, O; Stahl, A; Aldaya Martin, M; Asin, I; Bartosik, N; Behr, J; Behrens, U; Bell, A J; Bethani, A; Borras, K; Burgmeier, A; Cakir, A; Calligaris, L; Campbell, A; Choudhury, S; Costanza, F; Diez Pardos, C; Dolinska, G; Dooling, S; Dorland, T; Eckerlin, G; Eckstein, D; Eichhorn, T; Flucke, G; Garcia, J Garay; Geiser, A; Gizhko, A; Gunnellini, P; Hauk, J; Hempel, M; Jung, H; Kalogeropoulos, A; Karacheban, O; Kasemann, M; Katsas, P; Kieseler, J; Kleinwort, C; Korol, I; Krücker, D; Lange, W; Leonard, J; Lipka, K; Lobanov, A; Lohmann, W; Lutz, B; Mankel, R; Marfin, I; Melzer-Pellmann, I-A; Meyer, A B; Mittag, G; Mnich, J; Mussgiller, A; Naumann-Emme, S; Nayak, A; Ntomari, E; Perrey, H; Pitzl, D; Placakyte, R; Raspereza, A; Ribeiro Cipriano, P M; Roland, B; Ron, E; Sahin, M Ö; Salfeld-Nebgen, J; Saxena, P; Schoerner-Sadenius, T; Schröder, M; Seitz, C; Spannagel, S; Vargas Trevino, A D R; Walsh, R; Wissing, C; Blobel, V; Centis Vignali, M; Draeger, A R; Erfle, J; Garutti, E; Goebel, K; Görner, M; Haller, J; Hoffmann, M; Höing, R S; Junkes, A; Kirschenmann, H; Klanner, R; Kogler, R; Lapsien, T; Lenz, T; Marchesini, I; Marconi, D; Ott, J; Peiffer, T; Perieanu, A; Pietsch, N; Poehlsen, J; Poehlsen, T; Rathjens, D; Sander, C; Schettler, H; Schleper, P; Schlieckau, E; Schmidt, A; Seidel, M; Sola, V; Stadie, H; Steinbrück, G; Troendle, D; Usai, E; Vanelderen, L; Vanhoefer, A; Barth, C; Baus, C; Berger, J; Böser, C; Butz, E; Chwalek, T; De Boer, W; Descroix, A; Dierlamm, A; Feindt, M; Frensch, F; Giffels, M; Gilbert, A; Hartmann, F; Hauth, T; Husemann, U; Katkov, I; Kornmayer, A; Lobelle Pardo, P; Mozer, M U; Müller, T; Müller, Th; Nürnberg, A; Quast, G; Rabbertz, K; Röcker, S; Simonis, H J; Stober, F M; Ulrich, R; Wagner-Kuhr, J; Wayand, S; Weiler, T; Wolf, R; Anagnostou, G; Daskalakis, G; Geralis, T; Giakoumopoulou, V A; Kyriakis, A; Loukas, D; Markou, A; Markou, C; Psallidas, A; Topsis-Giotis, I; Agapitos, A; Kesisoglou, S; Panagiotou, A; Saoulidou, N; Stiliaris, E; Tziaferi, E; Aslanoglou, X; Evangelou, I; Flouris, G; Foudas, C; Kokkas, P; Manthos, N; Papadopoulos, I; Paradas, E; Strologas, J; Bencze, G; Hajdu, C; Hidas, P; Horvath, D; Sikler, F; Veszpremi, V; Vesztergombi, G; Zsigmond, A J; Beni, N; Czellar, S; Karancsi, J; Molnar, J; Palinkas, J; Szillasi, Z; Makovec, A; Raics, P; Trocsanyi, Z L; Ujvari, B; Swain, S K; Beri, S B; Bhatnagar, V; Gupta, R; Bhawandeep, U; Kalsi, A K; Kaur, M; Kumar, R; Mittal, M; Nishu, N; Singh, J B; Kumar, Ashok; Kumar, Arun; Ahuja, S; Bhardwaj, A; Choudhary, B C; Kumar, A; Malhotra, S; Naimuddin, M; Ranjan, K; Sharma, V; Banerjee, S; Bhattacharya, S; Chatterjee, K; Dutta, S; Gomber, B; Jain, Sa; Jain, Sh; Khurana, R; Modak, A; Mukherjee, S; Roy, D; Sarkar, S; Sharan, M; Abdulsalam, A; Dutta, D; Kumar, V; Mohanty, A K; Pant, L M; Shukla, P; Topkar, A; Aziz, T; Banerjee, S; Bhowmik, S; Chatterjee, R M; Dewanjee, R K; Dugad, S; Ganguly, S; Ghosh, S; Guchait, M; Gurtu, A; Kole, G; Kumar, S; Maity, M; Majumder, G; Mazumdar, K; Mohanty, G B; Parida, B; Sudhakar, K; Wickramage, N; Sharma, S; Bakhshiansohi, H; Behnamian, H; Etesami, S M; Fahim, A; Goldouzian, R; Khakzad, M; Mohammadi Najafabadi, M; Naseri, M; Paktinat Mehdiabadi, S; Rezaei Hosseinabadi, F; Safarzadeh, B; Zeinali, M; Felcini, M; Grunewald, M; Abbrescia, M; Calabria, C; Chhibra, S S; Colaleo, A; Creanza, D; Cristella, L; De Filippis, N; De Palma, M; Fiore, L; Iaselli, G; Maggi, G; Maggi, M; My, S; Nuzzo, S; Pompili, A; Pugliese, G; Radogna, R; Selvaggi, G; Sharma, A; Silvestris, L; Venditti, R; Verwilligen, P; Abbiendi, G; Benvenuti, A C; Bonacorsi, D; Braibant-Giacomelli, S; Brigliadori, L; Campanini, R; Capiluppi, P; Castro, A; Cavallo, F R; Codispoti, G; Cuffiani, M; Dallavalle, G M; Fabbri, F; Fanfani, A; Fasanella, D; Giacomelli, P; Grandi, C; Guiducci, L; Marcellini, S; Masetti, G; Montanari, A; Navarria, F L; Perrotta, A; 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Schmitt, M; Stoynev, S; Sung, K; Velasco, M; Won, S; Brinkerhoff, A; Chan, K M; Drozdetskiy, A; Hildreth, M; Jessop, C; Karmgard, D J; Kellams, N; Lannon, K; Lynch, S; Marinelli, N; Musienko, Y; Pearson, T; Planer, M; Ruchti, R; Smith, G; Valls, N; Wayne, M; Wolf, M; Woodard, A; Antonelli, L; Brinson, J; Bylsma, B; Durkin, L S; Flowers, S; Hart, A; Hill, C; Hughes, R; Kotov, K; Ling, T Y; Luo, W; Puigh, D; Rodenburg, M; Winer, B L; Wolfe, H; Wulsin, H W; Driga, O; Elmer, P; Hardenbrook, J; Hebda, P; Koay, S A; Lujan, P; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Quan, X; Saka, H; Stickland, D; Tully, C; Werner, J S; Zuranski, A; Brownson, E; Malik, S; Mendez, H; Ramirez Vargas, J E; Barnes, V E; Benedetti, D; Bortoletto, D; Gutay, L; Hu, Z; Jha, M K; Jones, M; Jung, K; Kress, M; Leonardo, N; Miller, D H; Neumeister, N; Primavera, F; Radburn-Smith, B C; Shi, X; Shipsey, I; Silvers, D; Svyatkovskiy, A; Wang, F; Xie, W; Xu, L; Zablocki, J; Parashar, N; Stupak, J; Adair, A; Akgun, B; Ecklund, K M; Geurts, F J M; Li, W; Michlin, B; Padley, B P; Redjimi, R; Roberts, J; Zabel, J; Betchart, B; Bodek, A; de Barbaro, P; Demina, R; Eshaq, Y; Ferbel, T; Galanti, M; Garcia-Bellido, A; Goldenzweig, P; Han, J; Harel, A; Hindrichs, O; Khukhunaishvili, A; Korjenevski, S; Petrillo, G; Verzetti, M; Vishnevskiy, D; Ciesielski, R; Demortier, L; Goulianos, K; Mesropian, C; Arora, S; Barker, A; Chou, J P; Contreras-Campana, C; Contreras-Campana, E; Duggan, D; Ferencek, D; Gershtein, Y; Gray, R; Halkiadakis, E; Hidas, D; Kaplan, S; Lath, A; Panwalkar, S; Park, M; Salur, S; Schnetzer, S; Sheffield, D; Somalwar, S; Stone, R; Thomas, S; Thomassen, P; Walker, M; Rose, K; Spanier, S; York, A; Bouhali, O; Castaneda Hernandez, A; Dalchenko, M; De Mattia, M; Dildick, S; Eusebi, R; Flanagan, W; Gilmore, J; Kamon, T; Khotilovich, V; Krutelyov, V; Montalvo, R; Osipenkov, I; Pakhotin, Y; Patel, R; Perloff, A; Roe, J; Rose, A; Safonov, A; Suarez, I; Tatarinov, A; Ulmer, K A; Akchurin, N; Cowden, C; Damgov, J; Dragoiu, C; Dudero, P R; Faulkner, J; Kovitanggoon, K; Kunori, S; Lee, S W; Libeiro, T; Volobouev, I; Appelt, E; Delannoy, A G; Greene, S; Gurrola, A; Johns, W; Maguire, C; Mao, Y; Melo, A; Sharma, M; Sheldon, P; Snook, B; Tuo, S; Velkovska, J; Arenton, M W; Boutle, S; Cox, B; Francis, B; Goodell, J; Hirosky, R; Ledovskoy, A; Li, H; Lin, C; Neu, C; Wolfe, E; Wood, J; Clarke, C; Harr, R; Karchin, P E; Kottachchi Kankanamge Don, C; Lamichhane, P; Sturdy, J; Belknap, D A; Carlsmith, D; Cepeda, M; Dasu, S; Dodd, L; Duric, S; Friis, E; Hall-Wilton, R; Herndon, M; Hervé, A; Klabbers, P; Lanaro, A; Lazaridis, C; Levine, A; Loveless, R; Mohapatra, A; Ojalvo, I; Perry, T; Pierro, G A; Polese, G; Ross, I; Sarangi, T; Savin, A; Smith, W H; Taylor, D; Vuosalo, C; Woods, N; Roinishvili, V

    Properties of the Higgs boson with mass near 125[Formula: see text] are measured in proton-proton collisions with the CMS experiment at the LHC. Comprehensive sets of production and decay measurements are combined. The decay channels include [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] pairs. The data samples were collected in 2011 and 2012 and correspond to integrated luminosities of up to 5.1[Formula: see text] at 7[Formula: see text] and up to 19.7[Formula: see text] at 8[Formula: see text]. From the high-resolution [Formula: see text] and [Formula: see text] channels, the mass of the Higgs boson is determined to be [Formula: see text]. For this mass value, the event yields obtained in the different analyses tagging specific decay channels and production mechanisms are consistent with those expected for the standard model Higgs boson. The combined best-fit signal relative to the standard model expectation is [Formula: see text] at the measured mass. The couplings of the Higgs boson are probed for deviations in magnitude from the standard model predictions in multiple ways, including searches for invisible and undetected decays. No significant deviations are found.

  15. Higgs v Hawking: a battle of the heavyweights that has shaken the world of theoretical physics

    CERN Multimedia

    Connor, S

    2002-01-01

    Stephen Hawking was accused yesterday of receiving instant credibility because of his celebrity status. His accuser was Professor Peter Higgs, who predicted the existence of the elementary particle, the Higgs Boson, in the 1960s (1 page).

  16. Exploring little Higgs models with ATLAS at the LHC

    International Nuclear Information System (INIS)

    Azuelos, G.; Benslama, K.; Costanzo, D.; Couture, G.; Garcia, J.E.; Hinchliffe, I.G.; Kanaya, N.; Lechowski, M.; Mehdiyev, R.; Polesello, G.; Ros, E.; Rousseau, D.

    2004-01-01

    We discuss possible searches for the new particles predicted by Little Higgs Models at the LHC. By using a simulation of the ATLAS detector, we demonstrate how the predicted quark, gauge bosons and additional Higgs bosons can be found and estimate the mass range over which their properties can be constrained

  17. PRECISION ELECTROWEAK MEASUREMENTS AND THE HIGGS MASS

    International Nuclear Information System (INIS)

    MARCIANO, W.J.

    2004-01-01

    The utility of precision electroweak measurements for predicting the Standard Model Higgs mass via quantum loop effects is discussed. Current constraints from m w and sin 2 θ w (m z ) ovr MS imply a relatively light Higgs ∼< 154 GeV which is consistent with Supersymmetry expectations. The existence of Supersymmetry is further suggested by a discrepancy between experiment and theory for the muon anomalous magnetic moment. Constraints from precision studies on other types of ''New Physics'' are also briefly described

  18. Holographic twin Higgs model.

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  19. Holographic Twin Higgs Model

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-01

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at mKK , naturally allowing for mKK beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  20. A theoretical limit on the Higgs mass

    International Nuclear Information System (INIS)

    Temiraliev, A.T.

    2007-01-01

    Full text: The standard model of particle physics, which describes masses through the Higgs mechanism, contains parameters - such as particle masses - whose origins are still unknown and which cannot be exactly predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark and W boson constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. Several more or less precise arguments can set the upper limit for a standard model Higgs particle. All of them follows the line that the standard model breaks down of the Higgs mass is pushed too far upwards. The theoretical bounds will be reviewed. With gauge-top quark Yukawa coupling unification the standard model Higgs boson mass is estimated to be about 135 GeV. In the article will be consider an approximation of 4-fermion interactions. And as a result, the most likely Higgs mass is 150 GeV. The upper limit on the Higgs mass at the 90 % confidence level is about 250 GeV

  1. Radiative corrections to the Higgs couplings in the triplet model

    International Nuclear Information System (INIS)

    KIKUCHI, M.

    2014-01-01

    The feature of extended Higgs models can appear in the pattern of deviations from the Standard Model (SM) predictions in coupling constants of the SM-like Higgs boson (h). We can thus discriminate extended Higgs models by precisely measuring the pattern of deviations in the coupling constants of h, even when extra bosons are not found directly. In order to compare the theoretical predictions to the future precision data at the ILC, we must evaluate the theoretical predictions with radiative corrections in various extended Higgs models. In this paper, we give our comprehensive study for radiative corrections to various Higgs boson couplings of h in the minimal Higgs triplet model (HTM). First, we define renormalization conditions in the model, and we calculate the Higgs coupling; gγγ, hWW, hZZ and hhh at the one loop level. We then evaluate deviations in coupling constants of the SM-like Higgs boson from the predictions in the SM. We find that one-loop contributions to these couplings are substantial as compared to their expected measurement accuracies at the ILC. Therefore the HTM has a possibility to be distinguished from the other models by comparing the pattern of deviations in the Higgs boson couplings.

  2. Search for Multiphoton Signatures of a Higgs Boson

    Energy Technology Data Exchange (ETDEWEB)

    Atramentov, Oleksiy Vladimirovich [Iowa State Univ., Ames, IA (United States)

    2006-07-01

    In this thesis we describe a search for a fermiophobic Higgs boson in 3γ+X events. The study has been performed on 0.83 fb-1 of data collected with the D0 detector that resides at one of the interaction regions of the Tevatron collider, the world's highest energy accelerator. This study was motivated by a fairly recent phenomenological paper [33] where it was noticed that in certain class of models (2HDM Type I and THM) the multi-photon final states like this one become detectable at the luminosity that has been collected by the D0 experiment by 2006. The mechanism that permits such final state becomes available when the conventional higgs production mechanism (higgs strahlung) are suppressed. This leads to the fact that Higgs boson with mass (mhf < 90 GeV/c2) lower than the current limit has not been excluded.

  3. Light Higgs and vector-like quarks without prejudice

    Science.gov (United States)

    Fajfer, Svjetlana; Greljo, Admir; Kamenik, Jernej F.; Mustać, Ivana

    2013-07-01

    Light vector-like quarks with non-renormalizable couplings to the Higgs are a common feature of models trying to address the electroweak (EW) hierarchy problem by treating the Higgs as a pseudo-goldstone boson of a global (approximate) symmetry. We systematically investigate the implications of the leading dimension five operators on Higgs phenomenology in presence of dynamical up- and down-type weak singlet as well as weak doublet vector-like quarks. After taking into account constraints from precision EW and flavour observables we show that contrary to the renormalizable models, significant modifications of Higgs properties are still possible and could shed light on the role of vector-like quarks in solutions to the EW hierarchy problem. We also briefly discuss implications of higher dimensional operators for direct vector-like quark searches at the LHC.

  4. Unitarizing Higgs Inflation

    CERN Document Server

    Giudice, Gian F

    2011-01-01

    We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.

  5. Unitarizing Higgs inflation

    International Nuclear Information System (INIS)

    Giudice, Gian F.; Lee, Hyun Min

    2011-01-01

    We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.

  6. Radiative corrections to the triple Higgs coupling in the inert Higgs doublet model

    International Nuclear Information System (INIS)

    Arhrib, Abdesslam; Benbrik, Rachid; Falaki, Jaouad El; Jueid, Adil

    2015-01-01

    We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and e + e − Linear Collider machines, accurate theoretical predictions are required. We study the radiative corrections to the triple Higgs coupling hhh and to hZZ, hWW couplings in the context of the IHDM. By combining several theoretical and experimental constraints on parameter space, we show that extra particles might modify the triple Higgs coupling near threshold regions. Finally, we discuss the effect of these corrections on the double Higgs production signal at the e + e − LC and show that they can be rather important.

  7. Higgs boson production and decay in little Higgs models with T-parity

    International Nuclear Information System (INIS)

    Chen, C.-R.; Tobe, Kazuhiro; Yuan, C.-P.

    2006-01-01

    We study Higgs boson production and decay in a certain class of little Higgs models with T-parity in which some T-parity partners of the Standard Model (SM) fermions gain their masses through Yukawa-type couplings. We find that the Higgs boson production cross section of a 120 GeV Higgs boson at the CERN LHC via gg fusion process at one-loop level could be reduced by about 45%, 35% and 20%, as compared to its SM prediction, for a relatively low new particle mass scale f=600, 700 and 1000 GeV, respectively. On the other hand, the weak boson fusion cross section is close to the SM value. Furthermore, the Higgs boson decay branching ratio into di-photon mode can be enhanced by about 35% in small Higgs mass region in certain case, for the total decay width of Higgs boson in the little Higgs model is always smaller than that in the SM

  8. Search for BSM Higgs bosons in fermion decay modes with ATLAS

    CERN Document Server

    Straessner, Arno; The ATLAS collaboration

    2017-01-01

    Many physics models beyond the Standard Model (BSM) predict an extension of the Higgs sector, like the general 2-Higgs Doublet Model (2HDM) or supersymmetric models. In case of one additional Higgs doublet, there are five physical Higgs bosons: two CP neutral states (h,H), one CP odd state (A) and two charged Higgs bosons (H±). Typically, the already observed Higgs boson is identified with the h Higgs boson, while the others are assumed to be heavy. This presentation is reporting on recent results of direct searches for heavy neutral and charged Higgs bosons by the ATLAS Collaboration, in particular analyzing direct Higgs boson decays to fermions, like $H^\\pm \\to \\tau\

  9. CP violation in the two-doublet Higgs sector of the MSSM

    International Nuclear Information System (INIS)

    Akhmetzyanova, Eh.N.; Dolgopolov, M.V.; Dubinin, M.N.

    2006-01-01

    Models with extended two-doublet Higgs sector are discussed in view of using their particular features to find out which sources of CP violation could take place in nature. It is considered the effective two-Higgs-doublet potential with complex parameters, when the CP invariance is broken both explicitly and spontaneously. For case of the two-doublet Higgs sector of the minimal supersymmetric model, when CP invariance is violated by the interactions of Higgs fields with the third generation of scalar quarks, the Higgs bosons mass spectrum in the case of maximal CP mixing is calculated which is significantly different from CP-conserving case. The phenomenological consequences for the Higgs mass spectrum in the decoupling regime and for the strong mixing case are considered [ru

  10. The Higgs boson and the quark top in the formalism of dispersion relations and the standard model

    International Nuclear Information System (INIS)

    Bouayed, N.

    2008-11-01

    The mechanism of spontaneous symmetry breaking responsible for the generation of masses for both the bosons and the fermions of the Standard Model remains a mystery, especially that the Higgs has still not been discovered. In this thesis I concentrate on the study of the scalar sector of the Standard Model where the Higgs with the other Goldstone Bosons reside. This sector can best be probed through the massive vector bosons and the top quark. The former, for their privileged coupling to the Higgs and because their longitudinal mode represents the Goldstone Bosons, and the top, because of its very strong Yukawa coupling, are very sensitive to the mechanism of symmetry breaking. I first focus on a situation where the Higgs is light and study the processes W - W + → tt-bar and ZZ → tt-bar. In order to unambiguously reveal a sign of New Physics, the Standard Model needs to be predicted precisely. In a first step I therefore study the electroweak and QCD one loop corrections for these processes. This requires a renormalisation of the electroweak gauge and top sectors and mastering some one-loop techniques. I then concentrate on extracting the purely electroweak contributions to the above processes after setting up an analytical formula for the universal photonic contribution. The New Physics affecting the top and W system is parameterized with the help of effective operators describing symmetry breaking. The effect of these operators is carefully compared to the effect of the one-loop radiative corrections before setting a limit on the parameters of these New Physics operators. To give more realistic results the WW and ZZ cross sections are turned into e + e - and pp cross sections by using a structure function approach. This allows an application to the phenomenology at future colliders (LHC:Large Hadron Collider and ILC: International Linear Collider). A second aspect of the work presented here concerns the situation where the Higgs is heavy. For a heavy Higgs

  11. If no Higgs then what?

    CERN Document Server

    Falkowski, A.; Kaminska, A.; Pokorski, S.; Weiler, A.

    2011-01-01

    In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions of parameter space where a minimal addition - a single spin-1 custodial SU(2) triplet resonance - allows one to retain perturbative control in all channels. Elastic scattering of longitudinal W and Z bosons alone seems to permit a very large cut-off beyond the Naive Dimensional Analysis expectation. We find however that including scattering of the spin-1 resonances then leads to an earlier onset of strong coupling. Most importantly for LHC searches, we define a self-consistent set-up with a well-defined range of validity without recourse to unitarization schemes whose physical meaning is obscure. We discuss the LHC phenomenology and the discovery reach for these electroweak resonances and mention the possibility of a nightmare scenario with no Higgs nor resonan...

  12. If no Higgs then what?

    Energy Technology Data Exchange (ETDEWEB)

    Falkowski, A. [Paris-Sud, Orsay (France). Lab. de Physique Theorique d' Orsay; Grojean, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Institut de Physique Theorique, CEA/Saclay, Gif-sur-Yvette (France); Kaminska, A. [Warsaw Univ. (Poland). Inst. of Theoretical Physics; Pokorski, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Warsaw Univ. (Poland). Inst. of Theoretical Physics; Weiler, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-09-15

    In the absence of a Higgs boson, the perturbative description of the Standard Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z bosons can extend the validity of the theory up to higher scales. We carefully identify regions of parameter space where a minimal addition - a single spin-1 SU(2){sub custodial}-triplet resonance - allows one to retain perturbative control in all channels. Elastic scattering of longitudinal W and Z bosons alone seems to permit a very large cut-off beyond the Naive Dimensional Analysis expectation. We find however that including scattering of the spin-1 resonances then leads to an earlier onset of strong coupling. Most importantly for LHC searches, we define a self-consistent set-up with a well-defined range of validity without recourse to unitarization schemes whose physical meaning is obscure. We discuss the LHC phenomenology and the discovery reach for these electroweak resonances and mention the possibility of a nightmare scenario with no Higgs nor resonance within the LHC reach. Finally, we discuss the effects of parity breaking in the heavy resonance sector which reduces the contributions to the S parameter. (orig.)

  13. Very boosted Higgs in gluon fusion

    CERN Document Server

    Grojean, Christophe; Schlaffer, Matthias; Weiler, Andreas

    2014-01-01

    The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the $t\\bar{t}h$ channel to pin down this crucial coupling. Presented first in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.

  14. Superheavy dark matter through Higgs portal operators

    Science.gov (United States)

    Kolb, Edward W.; Long, Andrew J.

    2017-11-01

    The WIMPzilla hypothesis is that the dark matter is a super-weakly-interacting and superheavy particle. Conventionally, the WIMPzilla abundance is set by gravitational particle production during or at the end of inflation. In this study we allow the WIMPzilla to interact directly with Standard Model fields through the Higgs portal, and we calculate the thermal production (freeze-in) of WIMPzilla dark matter from the annihilation of Higgs boson pairs in the plasma. The two particle-physics model parameters are the WIMPzilla mass and the Higgs-WIMPzilla coupling. The two cosmological parameters are the reheating temperature and the expansion rate of the universe at the end of inflation. We delineate the regions of parameter space where either gravitational or thermal production is dominant, and within those regions we identify the parameters that predict the observed dark matter relic abundance. Allowing for thermal production opens up the parameter space, even for Planck-suppressed Higgs-WIMPzilla interactions.

  15. Very boosted Higgs in gluon fusion

    Energy Technology Data Exchange (ETDEWEB)

    Grojean, C. [Univ. Autonoma de Barcelona, Bellaterra (Spain). ICREA at IFAE; Salvioni, E. [California Univ., Davis, CA (United States). Dept. of Physics; European Organization for Nuclear Research (CERN), Geneva (Switzerland); Padova Univ. (Italy). Dipt. di Fisica e Astronomica; INFN, Sezione di Padova (Italy); Schlaffer, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Weiler, A. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-12-15

    The Higgs production and decay rates offer a new way to probe new physics beyond the Standard Model. While dynamics aiming at alleviating the hierarchy problem generically predict deviations in the Higgs rates, the current experimental analyses cannot resolve the long- and short-distance contributions to the gluon fusion process and thus cannot access directly the coupling between the Higgs and the top quark. We investigate the production of a boosted Higgs in association with a high-transverse momentum jet as an alternative to the t anti th channel to pin down this crucial coupling. Presented rst in the context of an effective field theory, our analysis is then applied to models of partial compositeness at the TeV scale and of natural supersymmetry.

  16. The Higgs Boson Search and Discovery

    CERN Document Server

    Bernardi, Gregorio

    2016-01-01

    We present a brief account of the search for the Higgs boson at the three major colliders that have operated over the last three decades: LEP, the Tevatron, and the LHC. The experimental challenges encountered stemmed from the distinct event phenomenology as determined by the colliders energy and the possible values for the Higgs boson mass, and from the capability of these colliders to deliver as much collision data as possible to fully explore the mass spectrum within their reach. Focusing more on the hadron collider searches during the last decade, we discuss how the search for the Higgs boson was advanced through mastering the experimental signatures of standard theory backgrounds, through the comprehensive utilization of the features of the detectors involved in the searches, and by means of advanced data analysis techniques. The search culminated in 2012 with the discovery, by the ATLAS and CMS collaborations, of a Higgs-like particle with mass close to 125 GeV, confirmed more recently to have propertie...

  17. Inflation and the Higgs Scalar

    Energy Technology Data Exchange (ETDEWEB)

    Green, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2014-12-05

    This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A simple scalar model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.

  18. Julius Edgar Lilienfeld Prize Lecture: The Higgs Boson, String Theory, and the Real World

    Science.gov (United States)

    Kane, Gordon

    2012-03-01

    In this talk I'll describe how string theory is exciting because it can address most, perhaps all, of the questions we hope to understand about our world: why quarks and leptons make up our world, what forces form our world, cosmology, parity violation, and much more. I'll explain why string theory is testable in basically the same ways as the rest of physics, and why much of what is written about that is misleading. String theory is already or soon being tested in several ways, including correctly predicting the recently observed Higgs boson properties and mass, and predictions for dark matter, LHC physics, cosmological history, and more, from work in the increasingly active subfield ``string phenomenology.''

  19. Phenomenological consequences of supersymmetry

    International Nuclear Information System (INIS)

    Hinchliffe, I.; Littenberg, L.

    1982-01-01

    This paper deals with the phenomenological consequences of supersymmetric theories, and with the implications of such theories for future high energy machines. The paper represents the work of a subgroup at the meeting. The authors are concerned only with high energy predictions of supersymmetry; low energy consequences (for example in the K/sub o/K-bar/sub o/ system) are discussed in the context of future experiments by another group, and will be mentioned briefly only in the context of constraining existing models. However a brief section is included on the implication for proton decay, although detailed experimental questions are not discussed

  20. Low energy phenomenology

    CERN Document Server

    Schmid, C

    1972-01-01

    The following topics are discussed: theoretical tools; models; Pade approximants; theoretical predictions of pi pi S-waves; pi pi phase shifts from K/sub e4/; Chew Low extrapolation in pi p to pi /sup -/ pi /sup +/n; the KK cusp in pi pi to pi pi ; K pi phase shifts. (25 refs) . For pt. I see ibid., 265. The following topics are discussed: patterns of resonance couplings from exchange degeneracy; Reggeon couplings; clash of t and s channel structure in pole model; B/sub 4/ phenomenology; Odorico zeros; Barrelet zeros and phase shift ambiguities. (29 refs).

  1. HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). Dept. of Physics; Stefaniak, Tim; Williams, Karina E. [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver

    2013-12-15

    We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the {chi}{sup 2} likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

  2. HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

    International Nuclear Information System (INIS)

    Bechtle, Philip; Staal, Oscar; Brein, Oliver

    2013-12-01

    We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the χ 2 likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

  3. Yukawa Bound States and Their LHC Phenomenology

    Directory of Open Access Journals (Sweden)

    Enkhbat Tsedenbaljir

    2013-01-01

    Full Text Available We present the current status on the possible bound states of extra generation quarks. These include phenomenology and search strategy at the LHC. If chiral fourth-generation quarks do exist their strong Yukawa couplings, implied by current experimental lower bound on their masses, may lead to formation of bound states. Due to nearly degenerate 4G masses suggested by Precision Electroweak Test one can employ “heavy isospin” symmetry to classify possible spectrum. Among these states, the color-octet isosinglet vector ω 8 is the easiest to be produced at the LHC. The discovery potential and corresponding decay channels are covered in this paper. With possible light Higgs at ~125 GeV two-Higgs doublet version is briefly discussed.

  4. DI-HIGGS RESULTS FROM THE ATLAS AND CMS EXPERIMENTS

    CERN Document Server

    Kagan, Michael; The ATLAS collaboration

    2018-01-01

    Measurements of di-Higgs production are of fundamental importance to understanding the process of electroweak symmetry breaking and the structure of the Higgs potential. While the Standard Model (SM) predicted production cross section for this process is too small to be observed by current LHC datasets, searches for this process at the ATLAS and CMS experiments can limit the SM production rate, anomalous Higgs self-couplings and Beyond the SM di-Higgs interaction vertices, and contributions to this process from new heavy resonances. Results from current experimental searches by ATLAS and CMS using data from Run 1 (2009- 2013) and Run 2 (2015-2018) of the LHC are presented.

  5. A primer on Higgs boson low-energy theorems

    International Nuclear Information System (INIS)

    Dawson, S.; Haber, H.E.; California Univ., Santa Cruz, CA

    1989-05-01

    We give a pedagogical review of Higgs boson low-energy theorems and their applications in the study of light Higgs boson interactions with mesons and baryons. In particular, it is shown how to combine the chiral Lagrangian method with the Higgs low-energy theorems to obtain predictions for the interaction of Higgs bosons and pseudoscalar mesons. Finally, we discuss the relation between the low-energy theorems and a technique which makes use of the trace of the QCD energy-momentum tensor. 35 refs

  6. Studies of the SM Higgs boson and searches for BSM Higgs bosons with the ATLAS Detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00182253; The ATLAS collaboration

    2016-01-01

    The ATLAS collaboration has searched for the Standard Model Higgs Boson in the first LHC Run-2 data using 3.2 $fb^{-1}$ at 13 TeV. Results are presented in terms of central value and limits on the total cross-section in the 4l and $\\gamma\\gamma$ channels. Several "Beyond Standard Model" theories predict the existence of additional heavy Higgs particles or di-Higgs resonances. Searches are conducted using the $\\gamma\\gamma$, ZZ, WW and fermionic decay channels, and cover a large range of masses for the hypothetical resonances.

  7. Signatures of extra dimensions from upsilon decays with a light gaugephobic Higgs boson

    International Nuclear Information System (INIS)

    Galloway, Jamison; McElrath, Bob; McRaven, John

    2009-01-01

    We explore non-standard Higgs phenomenology in the gaugephobic Higgs model in which the Higgs can be lighter than the usually quoted current experimental bound. The Higgs propagates in the bulk of a 5D space-time and Electroweak Symmetry Breaking occurs by a combination of boundary conditions in the extra dimension and an elementary Higgs. The Higgs can thus have a significantly suppressed coupling to the other Standard Model fields. A large enough suppression can be found to escape all limits and allow for a Higgs of any mass, which would be associated with the discovery of W ' and Z ' Kaluza-Klein resonances at the LHC. The Higgs can be precisely discovered at B-factories while the LHC would be insensitive to it due to high backgrounds. In this Letter we study the Higgs discovery mode in Y(3S), Y(2S), and Y(1S) decays, and the model parameter space that will be probed by BaBar, Belle, and CLEO data. In the absence of an early discovery of a heavy Higgs at the LHC, A Super-B factory would be an excellent option to further probe this region

  8. Searches for the Higgs Boson with the ATLAS detector at the LHC

    International Nuclear Information System (INIS)

    Mazini, Rachid

    2007-01-01

    Searching for the Higgs boson lies at the heart of the physics program of the Large Hadron Collider (LHC). The prospects for Higgs searches with the ATLAS detector at the LHC are reviewed. The discovery potential of most prominent Higgs final states predicted by the Standard Model and the MSSM are reviewed. (Author)

  9. Search for rare and exotic Higgs Boson decay modes and Higgs Boson pair production with the ATLAS detector

    CERN Document Server

    Tong, Baojia; The ATLAS collaboration

    2018-01-01

    An enhanced production of double Higgs bosons or exotic decays of the Higgs boson would be two clear signs of beyond Standard Model physics. A search is performed for resonant and non-resonant Higgs boson pair production, where the two Higgs bosons decay to four bottom quarks. Another search is conducted for a Higgs boson decay to XX to four leptons. Both analyses use up to 36 ifb of p-p collision data collected by the ATLAS detector at 13 TeV. No significant excess is found. The observed 95% confidence level upper limit on the non-resonant Higgs boson pair production is 13 times the Standard Model prediction.

  10. Phenomenological approach to precise creep life prediction by means of quantitative evaluation of strain rate acceleration in secondary creep

    International Nuclear Information System (INIS)

    Sato, Hiroyuki; Miyano, Takaya

    2010-01-01

    A method of creep life prediction by means of Strain-Acceleration-Parameter (SAP), α, is presented. The authors show that the shape of creep curve can be characterized by SAP that reflects magnitude of strain-rate change in secondary creep. The SAP-values, α are evaluated on magnesium-aluminium solution hardened alloys. Reconstruction of creep curves by combinations of SAP and minimum-creep rates are successfully performed, and the curves reasonably agree with experiments. The advantage of the proposed method is that the required parameters evaluated from individual creep curves are directly connected with the minimum creep rate. The predicted times-to-failure agree well with that obtained by experiments, and possibility of precise life time prediction by SAP is pronounced.

  11. Implementation of a phenomenological DNB prediction model based on macroscale boiling flow processes in PWR fuel bundles

    International Nuclear Information System (INIS)

    Mohitpour, Maryam; Jahanfarnia, Gholamreza; Shams, Mehrzad

    2014-01-01

    Highlights: • A numerical framework was developed to mechanistically predict DNB in PWR bundles. • The DNB evaluation module was incorporated into the two-phase flow solver module. • Three-dimensional two-fluid model was the basis of two-phase flow solver module. • Liquid sublayer dryout model was adapted as CHF-triggering mechanism in DNB module. • Ability of DNB modeling approach was studied based on PSBT DNB tests in rod bundle. - Abstract: In this study, a numerical framework, comprising of a two-phase flow subchannel solver module and a Departure from Nucleate Boiling (DNB) evaluation module, was developed to mechanistically predict DNB in rod bundles of Pressurized Water Reactor (PWR). In this regard, the liquid sublayer dryout model was adapted as the Critical Heat Flux (CHF) triggering mechanism to reduce the dependency of the model on empirical correlations in the DNB evaluation module. To predict local flow boiling processes, a three-dimensional two-fluid formalism coupled with heat conduction was selected as the basic tool for the development of the two-phase flow subchannel analysis solver. Evaluation of the DNB modeling approach was performed against OECD/NRC NUPEC PWR Bundle tests (PSBT Benchmark) which supplied an extensive database for the development of truly mechanistic and consistent models for boiling transition and CHF. The results of the analyses demonstrated the need for additional assessment of the subcooled boiling model and the bulk condensation model implemented in the two-phase flow solver module. The proposed model slightly under-predicts the DNB power in comparison with the ones obtained from steady-state benchmark measurements. However, this prediction is acceptable compared with other codes. Another point about the DNB prediction model is that it has a conservative behavior. Examination of the axial and radial position of the first detected DNB using code-to-code comparisons on the basis of PSBT data indicated that the our

  12. Photon pairs: Quantum chromodynamics continuum and the Higgs ...

    Indian Academy of Sciences (India)

    is the largest. Results are compared with data from the Fermilab Tevatron and predictions are made for the large hadron collider. The QCD continuum is shown to have a softer spectrum than the Higgs boson signal at the LHC. Keywords. Higgs; photon pairs; quantum chromodynamics. PACS Nos 12.15.Ji; 12.38.Cy; 13.85.

  13. The minimal linear σ model for the Goldstone Higgs

    International Nuclear Information System (INIS)

    Feruglio, F.; Gavela, M.B.; Kanshin, K.; Machado, P.A.N.; Rigolin, S.; Saa, S.

    2016-01-01

    In the context of the minimal SO(5) linear σ-model, a complete renormalizable Lagrangian -including gauge bosons and fermions- is considered, with the symmetry softly broken to SO(4). The scalar sector describes both the electroweak Higgs doublet and the singlet σ. Varying the σ mass would allow to sweep from the regime of perturbative ultraviolet completion to the non-linear one assumed in models in which the Higgs particle is a low-energy remnant of some strong dynamics. We analyze the phenomenological implications and constraints from precision observables and LHC data. Furthermore, we derive the d≤6 effective Lagrangian in the limit of heavy exotic fermions.

  14. Electroweak vacuum stability in the Higgs-Dilaton theory

    Energy Technology Data Exchange (ETDEWEB)

    Shkerin, A. [Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL),CH-1015, Lausanne (Switzerland); Institute for Nuclear Research of the Russian Academy of Sciences,60th October Anniversary prospect 7a, 117312, Moscow (Russian Federation)

    2017-05-30

    We study the stability of the Electroweak (EW) vacuum in a scale-invariant extension of the Standard Model and General Relativity, known as a Higgs-Dilaton theory. The safety of the EW vacuum against possible transition towards another vacuum is a necessary condition for the model to be phenomenologically acceptable. We find that, within a wide range of parameters of the theory, the decay rate is significantly suppressed compared to that of the Standard Model. We also discuss properties of a tunneling solution that are specific to the Higgs-Dilaton theory.

  15. Interference effects in MSSM Higgs searches at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Elina [Weizmann Institute of Science, Rehovot (Israel); Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2017-05-15

    Complex parameters in the MSSM lead to mixing and interference between the two heavier neutral CP-even and CP-odd Higgs states. These effects can become very large in the case of almost degenerate states. In a CP-violating benchmark scenario, we investigate phenomenological implications of such interferences in view of the LHC searches for heavy Higgs bosons decaying to a pair of τ-leptons and produced in gluon fusion and in association with b-quarks. Strongly destructive effects leave parameter regions unconstrained that would be regarded as excluded if no interference terms were taken into account.

  16. Initial conditions for critical Higgs inflation

    Science.gov (United States)

    Salvio, Alberto

    2018-05-01

    It has been pointed out that a large non-minimal coupling ξ between the Higgs and the Ricci scalar can source higher derivative operators, which may change the predictions of Higgs inflation. A variant, called critical Higgs inflation, employs the near-criticality of the top mass to introduce an inflection point in the potential and lower drastically the value of ξ. We here study whether critical Higgs inflation can occur even if the pre-inflationary initial conditions do not satisfy the slow-roll behavior (retaining translation and rotation symmetries). A positive answer is found: inflation turns out to be an attractor and therefore no fine-tuning of the initial conditions is necessary. A very large initial Higgs time-derivative (as compared to the potential energy density) is compensated by a moderate increase in the initial field value. These conclusions are reached by solving the exact Higgs equation without using the slow-roll approximation. This also allows us to consistently treat the inflection point, where the standard slow-roll approximation breaks down. Here we make use of an approach that is independent of the UV completion of gravity, by taking initial conditions that always involve sub-planckian energies.

  17. Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model. I. Phenomenological predictions

    International Nuclear Information System (INIS)

    Wakamatsu, M.

    2003-01-01

    Theoretical predictions are given for the light-flavor sea-quark distributions in the nucleon including the strange quark ones on the basis of the flavor SU(3) version of the chiral quark soliton model. Careful account is taken of the SU(3) symmetry breaking effects due to the mass difference Δm s between the strange and nonstrange quarks, which is the only one parameter necessary for the flavor SU(3) generalization of the model. A particular emphasis of study is put on the light-flavor sea-quark asymmetry as exemplified by the observables d-bar(x)-u-bar(x),d-bar(x)/u-bar(x),Δu-bar(x)-Δd-bar(x) as well as on the particle-antiparticle asymmetry of the strange quark distributions represented by s(x)-s-bar(x),s(x)/s-bar(x),Δs(x)-Δs-bar(x) etc. As for the unpolarized sea-quark distributions, the predictions of the model seem qualitatively consistent with the available phenomenological information provided by the NMC data for d-bar(x)-u-bar(x), the E866 data for d-bar(x)/u-bar(x), the CCFR data and the fit of Barone et al. for s(x)/s-bar(x), etc. The model is shown to give several unique predictions also for the spin-dependent sea-quark distribution, such that Δs(x)<<Δs-bar(x) < or approx. 0 and Δd-bar(x)<0<Δu-bar(x), although the verification of these predictions must await more elaborate experimental investigations in the near future

  18. Higgs potential in the type II seesaw model

    International Nuclear Information System (INIS)

    Arhrib, A.; Benbrik, R.; Chabab, M.; Rahili, L.; Ramadan, J.; Moultaka, G.; Peyranere, M. C.

    2011-01-01

    The standard model Higgs sector, extended by one weak gauge triplet of scalar fields with a very small vacuum expectation value, is a very promising setting to account for neutrino masses through the so-called type II seesaw mechanism. In this paper we consider the general renormalizable doublet/triplet Higgs potential of this model. We perform a detailed study of its main dynamical features that depend on five dimensionless couplings and two mass parameters after spontaneous symmetry breaking, and highlight the implications for the Higgs phenomenology. In particular, we determine (i) the complete set of tree-level unitarity constraints on the couplings of the potential and (ii) the exact tree-level boundedness from below constraints on these couplings, valid for all directions. When combined, these constraints delineate precisely the theoretically allowed parameter space domain within our perturbative approximation. Among the seven physical Higgs states of this model, the mass of the lighter (heavier) CP even state h 0 (H 0 ) will always satisfy a theoretical upper (lower) bound that is reached for a critical value μ c of μ (the mass parameter controlling triple couplings among the doublet/triplet Higgses). Saturating the unitarity bounds, we find an upper bound m h 0 or approx. μ c and μ c . In the first regime the Higgs sector is typically very heavy, and only h 0 that becomes SM-like could be accessible to the LHC. In contrast, in the second regime, somewhat overlooked in the literature, most of the Higgs sector is light. In particular, the heaviest state H 0 becomes SM-like, the lighter states being the CP odd Higgs, the (doubly) charged Higgses, and a decoupled h 0 , possibly leading to a distinctive phenomenology at the colliders.

  19. Higgs properties in the Stealth Doublet Model

    Directory of Open Access Journals (Sweden)

    Wouda Glenn

    2013-11-01

    Full Text Available I present a model with two scalar doublets and a softly broken ℤ2 symmetry, where only one of the doublets gets a vacuum expectation value and couples to fermions at tree-level. The softly broken ℤ2 symmetry leads to interesting phenomenology such as mixing between the two doublets and a charged scalar H± which can be light and dominantly decays into Hγ. The model can also naturally reproduce an enhanced γγ signal of the newly observed Higgs boson at the LHC with mass 125 GeV.

  20. Numerical simulation of Higgs models

    International Nuclear Information System (INIS)

    Jaster, A.

    1995-10-01

    The SU(2) Higgs and the Schwinger model on the lattice were analysed. Numerical simulations of the SU(2) Higgs model were performed to study the finite temperature electroweak phase transition. With the help of the multicanonical method the distribution of an order parameter at the phase transition point was measured. This was used to obtain the order of the phase transition and the value of the interface tension with the histogram method. Numerical simulations were also performed at zero temperature to perform renormalization. The measured values for the Wilson loops were used to determine the static potential and from this the renormalized gauge coupling. The Schwinger model was simulated at different gauge couplings to analyse the properties of the Kaplan-Shamir fermions. The prediction that the mass parameter gets only multiplicative renormalization was tested and verified. (orig.)

  1. Exploring collider aspects of a neutrinophilic Higgs doublet model in multilepton channels

    Science.gov (United States)

    Huitu, Katri; Kärkkäinen, Timo J.; Mondal, Subhadeep; Rai, Santosh Kumar

    2018-02-01

    We consider a neutrinophilic Higgs scenario where the Standard Model is extended by one additional Higgs doublet and three generations of singlet right-handed Majorana neutrinos. Light neutrino masses are generated through mixing with the heavy neutrinos via the Type-I seesaw mechanism when the neutrinophilic Higgs gets a vacuum expectation value (VEV). The Dirac neutrino Yukawa coupling in this scenario can be sizable compared to those in the canonical Type-I seesaw mechanism owing to the small neutrinophilic Higgs VEV giving rise to interesting phenomenological consequences. We have explored various signal regions likely to provide a hint of such a scenario at the LHC as well as at future e+e- colliders. We have also highlighted the consequences of light neutrino mass hierarchies in collider phenomenology that can complement the findings of neutrino oscillation experiments.

  2. Phenomenology of colour exotic fermions

    International Nuclear Information System (INIS)

    Luest, D.

    1986-01-01

    The authors discuss the phenomenological consequences of a dynamical scenario according to which the electroweak symmetry breaking and generation of fermion masses is due to fermions that transform under high colour representations. Particular emphasis is given to the predictions for rare processes and to the spectrum of high colour boundstates. (Auth.)

  3. LHC Higgs physics beyond the Standard Model

    International Nuclear Information System (INIS)

    Spannowsky, M.

    2007-01-01

    The Large Hadron Collider (LHC) at CERN will be able to perform proton collisions at a much higher center-of-mass energy and luminosity than any other collider. Its main purpose is to detect the Higgs boson, the last unobserved particle of the Standard Model, explaining the riddle of the origin of mass. Studies have shown, that for the whole allowed region of the Higgs mass processes exist to detect the Higgs at the LHC. However, the Standard Model cannot be a theory of everything and is not able to provide a complete understanding of physics. It is at most an effective theory up to a presently unknown energy scale. Hence, extensions of the Standard Model are necessary which can affect the Higgs-boson signals. We discuss these effects in two popular extensions of the Standard Model: the Minimal Supersymmetric Standard Model (MSSM) and the Standard Model with four generations (SM4G). Constraints on these models come predominantly from flavor physics and electroweak precision measurements. We show, that the SM4G is still viable and that a fourth generation has strong impact on decay and production processes of the Higgs boson. Furthermore, we study the charged Higgs boson in the MSSM, yielding a clear signal for physics beyond the Standard Model. For small tan β in minimal flavor violation (MFV) no processes for the detection of a charged Higgs boson do exist at the LHC. However, MFV is just motivated by the experimental agreement of results from flavor physics with Standard Model predictions, but not by any basic theoretical consideration. In this thesis, we calculate charged Higgs boson production cross sections beyond the assumption of MFV, where a large number of free parameters is present in the MSSM. We find that the soft-breaking parameters which enhance the charged-Higgs boson production most are just bound to large values, e.g. by rare B-meson decays. Although the charged-Higgs boson cross sections beyond MFV turn out to be sizeable, only a detailed

  4. LHC Higgs physics beyond the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Spannowsky, M.

    2007-09-22

    The Large Hadron Collider (LHC) at CERN will be able to perform proton collisions at a much higher center-of-mass energy and luminosity than any other collider. Its main purpose is to detect the Higgs boson, the last unobserved particle of the Standard Model, explaining the riddle of the origin of mass. Studies have shown, that for the whole allowed region of the Higgs mass processes exist to detect the Higgs at the LHC. However, the Standard Model cannot be a theory of everything and is not able to provide a complete understanding of physics. It is at most an effective theory up to a presently unknown energy scale. Hence, extensions of the Standard Model are necessary which can affect the Higgs-boson signals. We discuss these effects in two popular extensions of the Standard Model: the Minimal Supersymmetric Standard Model (MSSM) and the Standard Model with four generations (SM4G). Constraints on these models come predominantly from flavor physics and electroweak precision measurements. We show, that the SM4G is still viable and that a fourth generation has strong impact on decay and production processes of the Higgs boson. Furthermore, we study the charged Higgs boson in the MSSM, yielding a clear signal for physics beyond the Standard Model. For small tan {beta} in minimal flavor violation (MFV) no processes for the detection of a charged Higgs boson do exist at the LHC. However, MFV is just motivated by the experimental agreement of results from flavor physics with Standard Model predictions, but not by any basic theoretical consideration. In this thesis, we calculate charged Higgs boson production cross sections beyond the assumption of MFV, where a large number of free parameters is present in the MSSM. We find that the soft-breaking parameters which enhance the charged-Higgs boson production most are just bound to large values, e.g. by rare B-meson decays. Although the charged-Higgs boson cross sections beyond MFV turn out to be sizeable, only a detailed

  5. Search for the standard model Higgs boson in the dimuon decay channel with the ATLAS detector

    International Nuclear Information System (INIS)

    Rudolph, Joerg Christian

    2014-01-01

    The search for the Standard Model Higgs boson was one of the key motivations to build the world's largest particle physics experiment to date, the Large Hadron Collider (LHC). This thesis is equally driven by this search, and it investigates the direct muonic decay of the Higgs boson. The decay into muons has several advantages: it provides a very clear final state with two muons of opposite charge, which can easily be detected. In addition, the muonic final state has an excellent mass resolution, such that an observed resonance can be pinned down in one of its key properties: its mass. Unfortunately, the decay of a Standard Model Higgs boson into a pair of muons is very rare, only two out of 10000 Higgs bosons are predicted to exhibit this decay. On top of that, the non-resonant Standard Model background arising from the Z/γ * →μμ process has a very similar signature, while possessing a much higher cross-section. For one produced Higgs boson, there are approximately 1.5 million Z bosons produced at the LHC for a centre-of-mass energy of 8 TeV. Two related analyses are presented in this thesis: the investigation of 20.7 fb -1 of the proton-proton collision dataset recorded by the ATLAS detector in 2012, referred to as standalone analysis, and the combined analysis as the search in the full run-I dataset consisting of proton-proton collision data recorded in 2011 and 2012, which corresponds to an integrated luminosity of L int =24.8 fb -1 . In each case, the dimuon invariant mass spectrum is examined for a narrow resonance on top of the continuous background distribution. The dimuon phenomenology and ATLAS detector performance serve as the foundations to develop analytical models describing the spectra. Using these analytical parametrisations for the signal and background mass distributions, the sensitivity of the analyses to systematic uncertainties due to Monte-Carlo simulation mismodeling are minimised. These residual systematic uncertainties are

  6. Top quark and Higgs physics in standard model extensions

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Patrick Jose

    2012-05-25

    In this thesis we have studied several extensions of the SM and their implications on the strength and structure of the tbW vertex, on the production and decays of pseudoscalar and heavy Higgs scalars at the LHC, and the effects that models with a fourth generation have on electroweak precision observables. Apart from the SM with a fourth generation of chiral fermions, the extensions we studied all feature an extended electroweak symmetry breaking (EWSB) sector. In the case of the type-II 2HDM and the MSSM, the extended EWSB sector consists of elementary Higgs fields. In the case of Topcolor assisted Technicolor (TC2), which is a model of dynamical EWSB, the scalar and pseudoscalar fields are composite. By scanning over the phenomenologically and theoretically allowed regions of the respective parameters spaces, we determined the largest possible cross sections σ(pp→φ→VV{sup '}) where VV{sup p}rime element of {W"+W"-, ZZγγ, Zγ} for both the heavy scalar and pseudoscalar states in the above models. We found that non-SUSY models with an extended Higgs sector and only three generations, namely the type-II 2HDM and the TC2, still allow for observable pseudoscalar cross sections σ(pp → A → VV') at the LHC. In particular for the final states W{sup +}W{sup -} and γγ. In the MSSM, the discovery of the pseudoscalar A through its decays into electroweak gauge bosons is very unlikely. However, scalar cross sections σ(pp→H→W{sup +}W{sup -}) can still be of observable size at the LHC in large parts of the MSSM parameter space. SM extensions with an extended EWSB sector and four chiral generations are strongly disfavoured; direct Higgs boson searches exclude large parts of the parameter space and it is challenging to bring such an extension into accordance with electroweak precision data. On the other hand, models with additional vector-like quarks and an extended Higgs sector are still viable. The SM with four chiral generations is (still) not

  7. Are there hidden scalars in LHC Higgs results?

    International Nuclear Information System (INIS)

    Arhrib, A.; Ferreira, P.M.; Santos, Rui

    2014-01-01

    The Higgs boson recently discovered at the Large Hadron Collider has shown to have couplings to the remaining particles well within what is predicted by the Standard Model. The search for other new heavy scalar states has so far revealed to be fruitless, imposing constraints on the existence of new scalar particles. However, it is still possible that any existing heavy scalars would preferentially decay to final states involving the light Higgs boson thus evading the current LHC bounds on heavy scalar states. Moreover, decays of the heavy scalars could increase the number of light Higgs bosons being produced. Since the number of light Higgs bosons decaying to Standard Model particles is within the predicted range, this could mean that part of the light Higgs bosons could have their origin in heavy scalar decays. This situation would occur if the light Higgs couplings to Standard Model particles were reduced by a concomitant amount. Using a very simple extension of the SM — the two-Higgs doublet model — we show that in fact we could already be observing the effect of the heavy scalar states even if all results related to the Higgs are in excellent agreement with the Standard Model predictions

  8. Updated Higgs cross section at approximate N{sup 3}LO

    Energy Technology Data Exchange (ETDEWEB)

    Bonvini, Marco [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ball, Richard D. [Edinburgh Univ. (United Kingdom). Tait Inst.; Forte, Stefano [Milano Univ. (Italy). Dipt. di Fisica; INFN, Milano (Italy); Marzani, Simone [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Ridolfi, Giovanni [Genova Univ. (Italy). Dipt. di Fisica; INFN, Genova (Italy)

    2014-04-15

    We update our estimate of the cross section for Higgs production in gluon fusion at next-to-next-to-next-to-leading order (N{sup 3}LO) in α{sub s} in view of the recent full computation of the result in the soft limit for infinite top mass, which determines a previously unknown constant. We briefly discuss the phenomenological implications. Results are available through the updated version of the ggHiggs code.

  9. Higgs Boson Pizza Day

    CERN Document Server

    Stefania Pandolfi

    2016-01-01

    CERN celebrated the fourth anniversary of the historical Higgs boson announcement with special pizzas.    400 pizzas were served on Higgs pizza day in Restaurant 1 at CERN to celebrate the fourth anniversary of the announcement of the discovery of the Higgs Boson (Image: Maximilien Brice/ CERN) What do the Higgs boson and a pizza have in common? Pierluigi Paolucci, INFN and CMS collaboration member, together with INFN president Fernando Ferroni found out the answer one day in Naples: the pizza in front of them looked exactly like a Higgs boson event display. A special recipe was then created in collaboration with the chef of the historic “Ettore” pizzeria in the St. Lucia area of Naples, and two pizzas were designed to resemble two Higgs boson decay channel event displays. The “Higgs Boson Pizza Day” was held on Monday, 4 July 2016, on the fourth anniversary of the announcement of the discovery of the Higgs boso...

  10. Lattice Higgs models

    International Nuclear Information System (INIS)

    Jersak, J.

    1986-01-01

    This year has brought a sudden interest in lattice Higgs models. After five years of only modest activity we now have many new results obtained both by analytic and Monte Carlo methods. This talk is a review of the present state of lattice Higgs models with particular emphasis on the recent development

  11. Handbook of LHC Higgs Cross Sections: 2. Differential Distributions

    CERN Document Server

    Dittmaier, S; Passarino, G; Tanaka, R; Alekhin, S; Alwall, J; Bagnaschi, E A; Banfi, A; Blumlein, J; Bolognesi, S; Chanon, N; Cheng, T; Cieri, L; Cooper-Sarkar, A M; Cutajar, M; Dawson, S; Davies, G; De Filippis, N; Degrassi, G; Denner, A; D'Enterria, D; Diglio, S; Di Micco, B; Di Nardo, R; Ellis, R K; Farilla, A; Farrington, S; Felcini, M; Ferrera, G; Flechl, M; de Florian, D; Forte, S; Ganjour, S; Garzelli, M V; Gascon-Shotkin, S; Glazov, S; Goria, S; Grazzini, M; Guillet, J -Ph; Hackstein, C; Hamilton, K; Harlander, R; Hauru, M; Heinemeyer, S; Hoche, S; Huston, J; Jackson, C; Jimenez-Delgado, P; Jorgensen, M D; Kado, M; Kallweit, S; Kardos, A; Kauer, N; Kim, H; Kovac, M; Kramer, M; Krauss, F; Kuo, C -M; Lehti, S; Li, Q; Lorenzo, N; Maltoni, F; Mellado, B; Moch, S O; Muck, A; Muhlleitner, M; Nadolsky, P; Nason, P; Neu, C; Nikitenko, A; Oleari, C; Olsen, J; Palmer, S; Paganis, S; Papadopoulos, C G; Petersen, T C; Petriello, F; Petrucci, F; Piacquadio, G; Pilon, E; Potter, C T; Price, J; Puljak, I; Quayle, W; Radescu, V; Rebuzzi, D; Reina, L; Rojo, J; Rosco, D; Salam, G P; Sapronov, A; Schaarschmidt, J; Schonherr, M; Schumacher, M; Siegert, F; Slavich, P; Spira, M; Stewart, I W; Stirling, W J; Stockli, F; Sturm, C; Tackmann, F J; Thorne, R S; Tommasini, D; Torrielli, P; Tramontano, F; Trocsanyi, Z; Ubiali, M; Uccirati, S; Acosta, M Vazquez; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Warsinsky, M; Weber, M; Wiesemann, M; Weiglein, G; Yu, J; Zanderighi, G

    2012-01-01

    This Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent developments.

  12. Generalized Higgs inflation

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tsutomu [Kyoto Univ. (Japan). Hakubi Center; Kyoto Univ. (Japan). Dept. of Physics; Takahashi, Tomo [Saga Univ. (Japan). Dept. of Physics; Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics; Yokoyama, Jun' ichi [Tokyo Univ. (JP). Research Center for the Early Universe (RESCEU); Tokyo Univ., Chiba (JP). Inst. for the Physics and Mathematics of the Universe (IPMU)

    2012-03-15

    We study Higgs inflation in the context of generalized G-inflation, i.e., the most general single-field inflation model with second-order field equations. The four variants of Higgs inflation proposed so far in the literature can be accommodated at one time in our framework. We also propose yet another class of Higgs inflation, the running Einstein inflation model, that can naturally arise from the generalized G-inflation framework. As a result, five Higgs inflation models in all should be discussed on an equal footing. Concise formulas for primordial fluctuations in these generalized Higgs inflation models are provided, which will be helpful to determine which model is favored from the future experiments and observations such as the Large Hadron Collider and the Planck satellite.

  13. Hunting the dark Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Duerr, Michael; Grohsjean, Alexander; Kahlhoefer, Felix; Schmidt-Hoberg, Kai; Schwanenberger, Christian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Penning, Bjoern [Bristol Univ. (United Kingdom). H.H. Wills Physics Lab.

    2017-05-15

    We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches.

  14. Strongly interacting Higgs bosons

    International Nuclear Information System (INIS)

    Appelquist, T.; Bernard, C.

    1980-01-01

    The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed

  15. Boosted Higgs shapes

    International Nuclear Information System (INIS)

    Schlaffer, Matthias; Spannowsky, Michael; Wymant, Chris

    2014-05-01

    The inclusive Higgs production rate through gluon fusion has been measured to be in agreement with the Standard Model (SM). We show that even if the inclusive Higgs production rate is very SM-like, a precise determination of the boosted Higgs transverse momentum shape offers the opportunity to see effects of natural new physics. These measurements are generically motivated by effective field theory arguments and specifically in extensions of the SM with a natural weak scale, like composite Higgs models and natural supersymmetry. We show in detail how a measurement at high transverse momentum of H→2l+p T via H→ττ and H→WW * could be performed and demonstrate that it offers a compelling alternative to the t anti tH channel. We discuss the sensitivity to new physics in the most challenging scenario of an exactly SM-like inclusive Higgs cross-section.

  16. Hunting the dark Higgs

    International Nuclear Information System (INIS)

    Duerr, Michael; Grohsjean, Alexander; Kahlhoefer, Felix; Schmidt-Hoberg, Kai; Schwanenberger, Christian; Penning, Bjoern

    2017-05-01

    We discuss a novel signature of dark matter production at the LHC resulting from the emission of an additional Higgs boson in the dark sector. The presence of such a dark Higgs boson is motivated simultaneously by the need to generate the masses of the particles in the dark sector and the possibility to relax constraints from the dark matter relic abundance by opening up a new annihilation channel. If the dark Higgs boson decays into Standard Model states via a small mixing with the Standard Model Higgs boson, one obtains characteristic large-radius jets in association with missing transverse momentum that can be used to efficiently discriminate signal from backgrounds. We present the sensitivities achievable in LHC searches for dark Higgs bosons with already collected data and demonstrate that such searches can probe large regions of parameter space that are inaccessible to conventional mono-jet or di-jet searches.

  17. Differential Higgs boson pair production at next-to-next-to-leading order in QCD

    International Nuclear Information System (INIS)

    Florian, Daniel de; Mazzitelli, Javier; Grazzini, Massimiliano; Hanga, Catalin; Lindert, Jonas M.; Kallweit, Stefan; Maierhoefer, Philipp; Rathlev, Dirk

    2016-06-01

    We report on the first fully differential calculation for double Higgs boson production through gluon fusion in hadron collisions up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. The calculation is performed in the heavy-top limit of the Standard Model, and in the phenomenological results we focus on pp collisions at √(s)=14 TeV. We present differential distributions through NNLO for various observables including the transverse-momentum and rapidity distributions of the two Higgs bosons. NNLO corrections are at the level of 10%-25% with respect to the next-to-leading order (NLO) prediction with a residual scale uncertainty of 5%-15% and an overall mild phase-space dependence. Only at NNLO the perturbative expansion starts to converge yielding overlapping scale uncertainty bands between NNLO and NLO in most of the phase-space. The calculation includes NLO predictions for pp→HH+jet+X. Corrections to the corresponding distributions exceed 50% with a residual scale dependence of 20%-30%.

  18. Minimal spontaneously broken hidden sector and its impact on Higgs boson physics at the CERN Large Hadron Collider

    International Nuclear Information System (INIS)

    Schabinger, Robert; Wells, James D.

    2005-01-01

    Little experimental data bears on the question of whether there is a spontaneously broken hidden sector that has no Standard Model quantum numbers. Here we discuss the prospects of finding evidence for such a hidden sector through renormalizable interactions of the Standard Model Higgs boson with a Higgs boson of the hidden sector. We find that the lightest Higgs boson in this scenario has smaller rates in standard detection channels, and it can have a sizeable invisible final state branching fraction. Details of the hidden sector determine whether the overall width of the lightest state is smaller or larger than the Standard Model width. We compute observable rates, total widths and invisible decay branching fractions within the general framework. We also introduce the 'A-Higgs Model', which corresponds to the limit of a hidden sector Higgs boson weakly mixing with the Standard Model Higgs boson. This model has only one free parameter in addition to the mass of the light Higgs state and it illustrates most of the generic phenomenology issues, thereby enabling it to be a good benchmark theory for collider searches. We end by presenting an analogous supersymmetry model with similar phenomenology, which involves hidden sector Higgs bosons interacting with MSSM Higgs bosons through D-terms

  19. Exploring holographic Composite Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Croon, Djuna [Department of Physics and Astronomy, University of Sussex,BN1 9QH Brighton (United Kingdom); Perimeter Institute for Theoretical Physics,Waterloo, ON (Canada); Dillon, Barry M.; Huber, Stephan J.; Sanz, Veronica [Department of Physics and Astronomy, University of Sussex,BN1 9QH Brighton (United Kingdom)

    2016-07-13

    Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM{sub 5}, to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of “colours” N, thus increasing the decay constant of the Goldstone Higgs. This is essentially a ‘Little Randall-Sundrum Model’, which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM{sub 5} with a small UV cutoff is not in tension with the current experimental data.

  20. Motivation and detectability of an invisibly decaying Higgs boson at the Fermilab Tevatron

    International Nuclear Information System (INIS)

    Martin, S.P.; Wells, J.D.

    1999-01-01

    A Higgs boson with a mass below 150 GeV has a total decay width of less than 20 MeV into accessible standard model states. This narrow width means that the usual branching fractions for such a light Higgs boson are highly susceptible to any new particles to which it has unsuppressed couplings. In particular, there are many reasonable and interesting theoretical ideas that naturally imply an invisibly decaying Higgs boson. The motivations include models with light supersymmetric neutralinos, spontaneously broken lepton number, radiatively generated neutrino masses, additional singlet scalar(s), or right-handed neutrinos in the extra dimensions of TeV gravity. We discuss these approaches to model building and their implications for Higgs boson phenomenology in future Fermilab Tevatron runs. We find, for example, that the Tevatron with 30 fb -1 integrated luminosity can make a 3σ observation in the l + l - +E/ T channel for a 125 GeV Higgs boson that is produced with the same strength as the standard model Higgs boson but always decays invisibly. We also analyze the b bar b+E/ T final state signal and conclude that it is not as sensitive, but it may assist in excluding the possibility of an invisibly decaying Higgs boson or enable confirmation of an observed signal in the dilepton channel. We argue that a comprehensive Higgs boson search at the Tevatron should include the possibility that the Higgs boson decays invisibly. copyright 1999 The American Physical Society

  1. Higgs boson mass bounds in the presence of a heavy fourth quark family

    Energy Technology Data Exchange (ETDEWEB)

    Bulava, John [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Gerhold, Philipp; Kallarackal, Jim; Nagy, Attila [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2013-01-15

    We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

  2. Higgs boson mass bounds in the presence of a heavy fourth quark family

    CERN Document Server

    Bulava, John; Nagy, Attila; Kallarackal, Jim; Jansen, Karl

    2012-01-01

    We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC.

  3. Higgs Boson Properties and Search for Additional Resonances

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00435709

    The Higgs boson was predicted by the Standard Model of particle physics and jointly discovered by the CMS and ATLAS experiments at LHC, in 2012. Following its discovery, the property measurements of the Higgs boson and the search for additional resonances become important research goals. The Standard Model is not the complete theory and leaves many questions unanswered, therefore it is important to search for any evidence of new physics beyond the SM. This thesis will briefly introduce the theoretical motivation for the Higgs boson, the production and decay mechanisms of the Higgs boson, and the methods used for analysis of the Higgs boson properties. The spin-1 and spin-2 Higgs hypotheses are tested in H->ZZ->4l channel, using the data recorded by CMS in Run1 of LHC. The exotic spin models were excluded and the Higgs boson is shown to agree with the Standard Model prediction of spin-0. The search for high-mass Higgs-like resonance is performed in H->ZZ->4l and H->ZZ->2l2q channels, using data recorded by CMS...

  4. Higgs Searches at DØ

    Science.gov (United States)

    Owen, Mark

    2009-09-01

    The Higgs boson is essential to achieve electroweak symmetry breaking in the Standard Model. Results on searches for the Higgs boson using data collected in pbar p collisions at √ s = 1.96 {TeV} with the DØ detector at the Fermilab Teva-tron collider are presented. The data, corresponding to integrated luminosities between 1 fb-1 and 2 fb-1 show no excess above the expected backgrounds and as such upper limits on the production cross section of Higgs bosons are set at the 95% confidence level.

  5. Higgs boson mass and new physics

    Energy Technology Data Exchange (ETDEWEB)

    Bezrukov, Fedor [Connecticut Univ., Storrs, CT (United States). Dept. of Physics; Brookhaven National Lab., Upton, NY (United States). RIKEN-BNL Research Center; Kalmykov, Mikhail Yu.; Kniehl, Bernd A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Shaposhnikov, Mikhail [Ecole Polytechnique Federale de Lausanne (Switzerland). Inst. de Theorie des Phenomenes Physiques

    2012-05-15

    We discuss the lower Higgs boson mass bounds which come from the absolute stability of the Standard Model (SM) vacuum and from the Higgs inflation, as well as the prediction of the Higgs boson mass coming from asymptotic safety of the SM. We account for the 3-loop renormalization group evolution of the couplings of the Standard Model and for a part of two-loop corrections that involve the QCD coupling {alpha}{sub s} to initial conditions for their running. This is one step above the current state of the art procedure (''one-loop matching-two-loop running''). This results in reduction of the theoretical uncertainties in the Higgs boson mass bounds and predictions, associated with the Standard Model physics, to 1-2 GeV. We find that with the account of existing experimental uncertainties in the mass of the top quark and {alpha}{sub s} (taken at 2{sigma} level) the bound reads M{sub H} {>=} M{sub min} (equality corresponds to the asymptotic safety prediction), where M{sub min}=129{+-}6 GeV. We argue that the discovery of the SM Higgs boson in this range would be in agreement with the hypothesis of the absence of new energy scales between the Fermi and Planck scales, whereas the coincidence of M{sub H} with M{sub min} would suggest that the electroweak scale is determined by Planck physics. In order to clarify the relation between the Fermi and Planck scale a construction of an electron-positron or muon collider with a center of mass energy {proportional_to}200+200 GeV (Higgs and t-quark factory) would be needed.

  6. Higgs boson mass and new physics

    International Nuclear Information System (INIS)

    Bezrukov, Fedor; Brookhaven National Lab., Upton, NY; Kalmykov, Mikhail Yu.; Kniehl, Bernd A.; Shaposhnikov, Mikhail

    2012-05-01

    We discuss the lower Higgs boson mass bounds which come from the absolute stability of the Standard Model (SM) vacuum and from the Higgs inflation, as well as the prediction of the Higgs boson mass coming from asymptotic safety of the SM. We account for the 3-loop renormalization group evolution of the couplings of the Standard Model and for a part of two-loop corrections that involve the QCD coupling α s to initial conditions for their running. This is one step above the current state of the art procedure (''one-loop matching-two-loop running''). This results in reduction of the theoretical uncertainties in the Higgs boson mass bounds and predictions, associated with the Standard Model physics, to 1-2 GeV. We find that with the account of existing experimental uncertainties in the mass of the top quark and α s (taken at 2σ level) the bound reads M H ≥ M min (equality corresponds to the asymptotic safety prediction), where M min =129±6 GeV. We argue that the discovery of the SM Higgs boson in this range would be in agreement with the hypothesis of the absence of new energy scales between the Fermi and Planck scales, whereas the coincidence of M H with M min would suggest that the electroweak scale is determined by Planck physics. In order to clarify the relation between the Fermi and Planck scale a construction of an electron-positron or muon collider with a center of mass energy ∝200+200 GeV (Higgs and t-quark factory) would be needed.

  7. Phenomenology of atmospheric neutrinos

    Directory of Open Access Journals (Sweden)

    Fedynitch Anatoli

    2016-01-01

    Full Text Available The detection of astrophysical neutrinos, certainly a break-through result, introduced new experimental challenges and fundamental questions about acceleration mechanisms of cosmic rays. On one hand IceCube succeeded in finding an unambiguous proof for the existence of a diffuse astrophysical neutrino flux, on the other hand the precise determination of its spectral index and normalization requires a better knowledge about the atmospheric background at hundreds of TeV and PeV energies. Atmospheric neutrinos in this energy range originate mostly from decays of heavy-flavor mesons, which production in the phase space relevant for prompt leptons is uncertain. Current accelerator-based experiments are limited by detector acceptance and not so much by the collision energy. This paper recaps phenomenological aspects of atmospheric leptons and calculation methods, linking recent progress in flux predictions with particle physics at colliders, in particular the Large Hadron Collider.

  8. Constraints on the trilinear Higgs self coupling from precision observables

    Energy Technology Data Exchange (ETDEWEB)

    Degrassi, G. [Dipartimento di Matematica e Fisica, Università di Roma Tre andINFN - Sezione di Roma Tre,I-00146 Rome (Italy); Fedele, M. [Dipartimento di Fisica, Università di Roma “La Sapienza” andINFN - Sezione di Roma,I-00185 Rome (Italy); Giardino, P.P. [Physics Department, Brookhaven National Laboratory,Upton, New York 11973 (United States)

    2017-04-27

    We present the constraints on the trilinear Higgs self coupling that arise from loop effects in the W boson mass and the effective sine predictions. We compute the contributions to these precision observables of two-loop diagrams featuring an anomalous trilinear Higgs self coupling. We explicitly show that the same anomalous contributions are found if the analysis of m{sub W} and sin{sup 2} θ{sub eff}{sup lep} is performed in a theory in which the scalar potential in the Standard Model Lagrangian is modified by an (in)finite tower of (Φ{sup †}Φ){sup n} terms with Φ the Higgs doublet. We find that the bounds on the trilinear Higgs self coupling from precision observables are competitive with those coming from Higgs pair production.

  9. Inflation from the Higgs field false vacuum with hybrid potential

    DEFF Research Database (Denmark)

    Masina, I.; Notari, A.

    2012-01-01

    We have recently suggested [1, 2] that Inflation could have started in a local minimum of the Higgs potential at field values of about 10(15) - 10(17) GeV, which exists for a narrow band of values of the top quark and Higgs masses and thus gives rise to a prediction on the Higgs mass...... we present an alternative possibility with an additional subdominant scalar very weakly coupled to the Higgs, realizing an (inverted) hybrid Inflation scenario. Interestingly, we show that such model has an additional constraint m(H) ..., this selects a narrower range 10(-4) less than or similar to r Higgs mass of about m(H)

  10. Search for neutral MSSM Higgs bosons at LEP

    CERN Document Server

    Schael, S.; Bruneliere, R.; De Bonis, I.; Decamp, D.; Goy, C.; Jezequel, S.; Lees, J.P.; Martin, F.; Merle, E.; Minard, M.N.; Pietrzyk, B.; Trocme, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Martinez, M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; De Filippis, N.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Barklow, T.; Buchmuller, O.; Cattaneo, M.; Clerbaux, B.; Drevermann, H.; Forty, R.W.; Frank, M.; Gianotti, F.; Hansen, J.B.; Harvey, J.; Hutchcroft, D.E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Teubert, F.; Valassi, A.; Videau, I.; Badaud, F.; Dessagne, S.; Falvard, A.; Fayolle, D.; Gay, P.; Jousset, J.; Michel, B.; Monteil, S.; Pallin, D.; Pascolo, J.M.; Perret, P.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Kraan, A.C.; Nilsson, B.S.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.C.; Machefert, F.; Rouge, A.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bossi, F.; Capon, G.; Cerutti, F.; Chiarella, V.; Mannocchi, G.; Laurelli, P.; Mannocchi, G.; Murtas, G.P.; Passalacqua, L.; Kennedy, J.; Lynch, J.G.; Negus, P.; O'Shea, V.; Thompson, A.S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E.E.; Putzer, A.; Stenzel, H.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Cameron, W.; Davies, G.; Dornan, P.J.; Girone, M.; Marinelli, N.; Nowell, J.; Rutherford, S.A.; Sedgbeer, J.K.; Thompson, J.C.; White, R.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Clarke, D.P.; Ellis, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Pearson, M.R.; Robertson, N.A.; Smizanska, M.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Blumenschein, U.; Holldorfer, F.; Jakobs, K.; Kayser, F.; Muller, A.S.; Renk, B.; Sander, H.G.; Schmeling, S.; Wachsmuth, H.; Zeitnitz, C.; Ziegler, T.; Bonissent, A.; Coyle, P.; Curtil, C.; Ealet, A.; Fouchez, D.; Payre, P.; Tilquin, A.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Manner, W.; Moser, H.G.; Settles, R.; Villegas, M.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Jacholkowska, A.; Serin, L.; Veillet, J.J.; Azzurri, P.; Bagliesi, G.; Boccali, T.; Foa, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Spagnolo, P.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Awunor, O.; Blair, G.A.; Cowan, G.; Garcia-Bellido, A.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Ward, J.J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Fabbro, B.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Tuchming, B.; Vallage, B.; Litke, A.M.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Hodgson, P.N.; Lehto, M.; Thompson, L.F.; Bohrer, A.; Brandt, S.; Grupen, C.; Hess, J.; Ngac, A.; Prange, G.; Borean, C.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S.R.; Berkelman, K.; Cranmer, K.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P.A.; Nielsen, J.; Pan, Y.B.; von Wimmersperg-Toeller, J.H.; Wiedenmann, W.; Wu, J.; Wu, S.L.; Wu, X.; Zobernig, G.; Dissertori, G.; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Buschbeck, B.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, P.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S.U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; de Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, P.; Gazis, E.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, J.N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E.K.; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Monig, Klaus; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, T.D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, P.; Van Eldik, J.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, A.; Achard, P.; Zupan, M.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, V.P.; Anselmo, F.; Arefiev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Yu.; Ganguli, S.N.; Garcia-Abia, P.; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, G.; Grimm, O.; Gruenewald, M.W.; Guida, M.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, A.; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, J.; Jin, B.N.; Jindal, P.; Jones, L.W.; de Jong, P.; Josa-Mutuberra, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, J.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Nowak, H.; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Piccolo, D.; Pierella, F.; Pieri, M.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofiev, D.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Rembeczki, S.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, S.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, C.; Ting, S.C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Vesztergombi, G.; Vetlitsky, I.; Viertel, G.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.; Abbiendi, G.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, J.; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, R.M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; de Jong, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, J.W.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, M.; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, K.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jost, U.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, P.; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Poli, B.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, D.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, L.; Heinemeyer, S.; Pilaftsis, A.; Weiglein, G.

    2006-01-01

    The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric Standard Model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of ``benchmark" models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter tanb and, in some scenarios, on the masses of neutral Higgs bosons.

  11. WIMP Dark Matter interpretation of Higgs results

    CERN Document Server

    Wang, Renjie; The ATLAS collaboration

    2017-01-01

    The results from searching for dark matter either directly from invisible decay of Higgs bosons or in association with a Higgs boson at the LHC are presented. No significant excess is found beyond the Standard Model prediction, and upper limits are set on the production cross section times branching fraction using data collected in proton-proton collisions at center-of-mass energies of 13 TeV by the ATLAS and CMS detectors. An interpreted upper limit is presented on the allowed dark matter-nucleon scattering cross section.

  12. Exploring extended scalar sectors with di-Higgs signals: a Higgs EFT perspective

    Science.gov (United States)

    Corbett, Tyler; Joglekar, Aniket; Li, Hao-Lin; Yu, Jiang-Hao

    2018-05-01

    We consider extended scalar sectors of the Standard Model as ultraviolet complete motivations for studying the effective Higgs self-interaction operators of the Standard Model effective field theory. We investigate all motivated heavy scalar models which generate the dimension-six effective operator, | H|6, at tree level and proceed to identify the full set of tree-level dimension-six operators by integrating out the heavy scalars. Of seven models which generate | H|6 at tree level only two, quadruplets of hypercharge Y = 3 Y H and Y = Y H , generate only this operator. Next we perform global fits to constrain relevant Wilson coefficients from the LHC single Higgs measurements as well as the electroweak oblique parameters S and T. We find that the T parameter puts very strong constraints on the Wilson coefficient of the | H|6 operator in the triplet and quadruplet models, while the singlet and doublet models could still have Higgs self-couplings which deviate significantly from the standard model prediction. To determine the extent to which the | H|6 operator could be constrained, we study the di-Higgs signatures at the future 100 TeV collider and explore future sensitivity of this operator. Projected onto the Higgs potential parameters of the extended scalar sectors, with 30 ab-1 luminosity data we will be able to explore the Higgs potential parameters in all seven models.

  13. The Higgs mass beyond the CMSSM

    International Nuclear Information System (INIS)

    Ellis, John; Luo, Feng; Olive, Keith A.; Sandick, Pearl

    2013-01-01

    The apparent discovery of a Higgs boson with mass ∝125 GeV has had a significant impact on the constrained minimal supersymmetric extension of the Standard Model (the CMSSM). Much of the low-mass parameter space in the CMSSM has been excluded by supersymmetric particle searches at the LHC as well as by the Higgs mass measurement and the emergent signal for B s →μ + μ - . Here, we consider the impact of these recent LHC results on several variants of the CMSSM with a primary focus on obtaining a Higgs mass of ∝125 GeV. In particular, we consider the one- and two-parameter extensions of the CMSSM with one or both of the Higgs masses set independently of the common sfermion mass, m 0 (the NUHM1,2). We also consider the one-parameter extension of the CMSSM in which the input universality scale M in is below the GUT scale (the sub-GUT CMSSM). Finally, we reconsider mSUGRA models with sub-GUT universality, which have the same number of parameters as the CMSSM. We find that when M in GUT large regions of parameter space open up where the relic density of neutralinos can successfully account for dark matter with a Higgs boson mass ∝125 GeV. Interestingly, we find that the preferred range of the A-term in sub-GUT mSUGRA models straddles that predicted by the simplest Polonyi model. (orig.)

  14. Induced gravity with Higgs potential. Elementary interactions and quantum processes

    Energy Technology Data Exchange (ETDEWEB)

    Bezares Roder, Nils Manuel

    2010-07-01

    relation between density and pressure in galactodynamics to that of solar-relativistic behavior appears for the dominance of phenomenological Dark Matter in galaxies. - Within spherical symmetry gravitationally repulsive issues of induced gravity are concluded. - Fundamental relations of cosmology within induced gravity with Higgs potential are derived for a Friedmann-Robertson-Walker symmetry. Cosmic acceleration and dark-matter phenomenology are analyzed in virtue of the generalized Friedmann equations, the equations of state, cosmic deceleration and density parameters. - Indications of a possible finite initial state of the Universe are achieved for a Friedmann cosmology together with accelerating behavior in such a state as well as in the current Universe. (orig.)

  15. Induced gravity with Higgs potential. Elementary interactions and quantum processes

    International Nuclear Information System (INIS)

    Bezares Roder, Nils Manuel

    2010-01-01

    density and pressure in galactodynamics to that of solar-relativistic behavior appears for the dominance of phenomenological Dark Matter in galaxies. - Within spherical symmetry gravitationally repulsive issues of induced gravity are concluded. - Fundamental relations of cosmology within induced gravity with Higgs potential are derived for a Friedmann-Robertson-Walker symmetry. Cosmic acceleration and dark-matter phenomenology are analyzed in virtue of the generalized Friedmann equations, the equations of state, cosmic deceleration and density parameters. - Indications of a possible finite initial state of the Universe are achieved for a Friedmann cosmology together with accelerating behavior in such a state as well as in the current Universe. (orig.)

  16. Higgs to bb in the VBF channel

    CERN Document Server

    CMS Collaboration

    2013-01-01

    A search for the standard model Higgs boson in the vector boson fusion production channel with decay to bottom quarks is reported. A data sample comprising 19.0~fb$^{-1}$ of proton-proton collisions at $\\sqrt{s}=8$~TeV collected during the 2012 running period has been analyzed and 95\\% Confidence Level upper limits are derived for five mass points from 115 to 135 GeV. At a Higgs boson mass of 125~GeV the observed limit is 3.6 while the expected limit is 3.0 times the standard model prediction. For a 125 GeV Higgs boson signal the fitted signal strength is $\\mu=\\sigma/\\sigma_{\\rm SM}=0.7\\pm1.4$.

  17. Higgs inflation at the critical point

    CERN Document Server

    Bezrukov, Fedor

    2014-01-01

    Higgs inflation can occur if the Standard Model (SM) is a self-consistent effective field theory up to inflationary scale. This leads to a lower bound on the Higgs boson mass, $M_h \\geq M_{\\text{crit}}$. If $M_h$ is more than a few hundreds of MeV above the critical value, the Higgs inflation predicts the universal values of inflationary indexes, $r\\simeq 0.003$ and $n_s\\simeq 0.97$, independently on the Standard Model parameters. We show that in the vicinity of the critical point $M_{\\text{crit}}$ the inflationary indexes acquire an essential dependence on the mass of the top quark $m_t$ and $M_h$. In particular, the amplitude of the gravitational waves can exceed considerably the universal value.

  18. Pseudo-Observables in Higgs decays

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    In view of future high-statistics data, it is useful to define a framework for precise determinations of the properties of the Higgs particle valid in generic extensions of the Standard Model. For Higgs decays, this goal can be achieved with a limited set of "Pseudo-Observables" (PO). The PO provides a systematic generalization of the "kappa-framework" so far adopted by the LHC experiments and provide a useful bridge between data and theory predictions. I discuss how the PO are defined, with particular attention to the h->4f decays, and how they can be used to test various dynamical and symmetry hypotheses about the Higgs sector. The relation between PO and EFT couplings is also discussed.

  19. Combined mass and couplings of the Higgs boson at CMS

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    From the high-resolution gammagamma and ZZ channels, the mass of the Higgs boson is measured to be 125.02+0.26- 0.27 (stat)+0.14-0.15 (syst) GeV. The event yields relative to the standard model predictions have been measured and the Higgs boson couplings to other particles are tested for deviations from the standard model predictions.

  20. Hunting the mysterious Higgs

    CERN Multimedia

    Parker, Andy

    1996-01-01

    The Higgs boson is the most mysterious of all the fundamental particles. It accounts for how other particles acquired mass just after the beginning of the Universe. LEP-2 and the LHC at CERN will hunt it down between them

  1. Very light dilaton and naturally light Higgs boson

    Science.gov (United States)

    Hong, Deog Ki

    2018-02-01

    We study very light dilaton, arising from a scale-invariant ultraviolet theory of the Higgs sector in the standard model of particle physics. Imposing the scale symmetry below the ultraviolet scale of the Higgs sector, we alleviate the fine-tuning problem associated with the Higgs mass. When the electroweak symmetry is spontaneously broken radiatively à la Coleman-Weinberg, the dilaton develops a vacuum expectation value away from the origin to give an extra contribution to the Higgs potential so that the Higgs mass becomes naturally around the electroweak scale. The ultraviolet scale of the Higgs sector can be therefore much higher than the electroweak scale, as the dilaton drives the Higgs mass to the electroweak scale. We also show that the light dilaton in this scenario is a good candidate for dark matter of mass m D ˜ 1 eV - 10 keV, if the ultraviolet scale is about 10-100 TeV. Finally we propose a dilaton-assisted composite Higgs model to realize our scenario. In addition to the light dilaton the model predicts a heavy U(1) axial vector boson and two massive, oppositely charged, pseudo Nambu-Goldstone bosons, which might be accessible at LHC.

  2. Review of Physics Results from the Tevatron: Higgs Boson Physics

    International Nuclear Information System (INIS)

    Junk, Thomas R.; Juste, Aurelio

    2015-01-01

    We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DO. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeVHiggs boson with a mass in the range 115 GeVHiggs boson mass of m H =125 GeV, studies of Higgs boson properties were performed, including measurements of the product of the cross section times branching the ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model

  3. Invisible Higgs boson decay with B→Kνν constraint

    International Nuclear Information System (INIS)

    Kim, C. S.; Park, Seong Chan; Wang Kai; Zhu Guohuai

    2010-01-01

    If the Higgs boson were the only particle within the LHC accessible range, precision measurement of the Higgs's properties would play a unique role in studying electroweak symmetry breaking as well as possible new physics. We try to use low energy experiments such as rare B decay to constrain a challenging decay mode of Higgs, in which a Higgs decays to a pair of light (≅1∼2 GeV) SM singlet S and becomes invisible. By using the current experimental bound of rare decay B→Kνν and computing the contribution of B→KSS to (the) B→K+Ee, we obtain an upper bound on the Higgs coupling to such light singlet. It is interesting that the partial width of the invisible decay mode h→SS by taking the upper bound value of coupling is at a comparable level with h→WW/ZZ or WW ( * ) decay modes, making the Higgs identifiable but with a different predicted decay branching ratio from [the] standard model Higgs decay. It will then have an impact on precision measurement of the Higgs's properties. We also study the implication for cosmology from such a light singlet and propose a solution to the potential problem.

  4. A Natural Extension of Standard Warped Higher-Dimensional Compactifications: Theory and Phenomenology

    Science.gov (United States)

    Hong, Sungwoo

    Warped higher-dimensional compactifications with "bulk'' standard model, or their AdS/CFT dual as the purely 4D scenario of Higgs compositeness and partial compositeness, offer an elegant approach to resolving the electroweak hierarchy problem as well as the origins of flavor structure. However, low-energy electroweak/flavor/CP constraints and the absence of non-standard physics at LHC Run 1 suggest that a "little hierarchy problem'' remains, and that the new physics underlying naturalness may lie out of LHC reach. Assuming this to be the case, we show that there is a simple and natural extension of the minimal warped model in the Randall-Sundrum framework, in which matter, gauge and gravitational fields propagate modestly different degrees into the IR of the warped dimension, resulting in rich and striking consequences for the LHC (and beyond). The LHC-accessible part of the new physics is AdS/CFT dual to the mechanism of "vectorlike confinement'', with TeV-scale Kaluza-Klein excitations of the gauge and gravitational fields dual to spin-0,1,2 composites. Unlike the minimal warped model, these low-lying excitations have predominantly flavor-blind and flavor/CP-safe interactions with the standard model. In addition, the usual leading decay modes of the lightest KK gauge bosons into top and Higgs bosons are suppressed. This effect permits erstwhile subdominant channels to become significant. These include flavor-universal decays to all pairs of SM fermions, and a novel channel--decay to a radion and a SM gauge boson, followed by radion decay to a pair of SM gauge bosons. We present a detailed phenomenological study of the latter cascade decay processes. Remarkably, this scenario also predicts small deviations from flavor-blindness originating from virtual effects of Higgs/top compositeness at O(10) TeV, with subdominant resonance decays into a pair of Higgs/top-rich final states, giving the LHC an early "preview'' of the nature of the resolution of the hierarchy

  5. Beyond the standard Higgs at the LHC. Present constraints on little Higgs models and future prospects

    International Nuclear Information System (INIS)

    Tonini, Marco

    2014-11-01

    This thesis discusses the consistency of different Little Higgs models with the collected collider data as of the summer of 2013. Moreover, future prospects for possible discoveries and mass measurement methods of new physics signals at the foreseen LHC run II with increased center-of-mass energy are presented. Little Higgs models belong to a class of extensions of the Standard Higgs model, predicting a strong interaction regime at a compositeness scale Λ=4πf approximate global symmetry spontaneously broken at the scale f. A natural hierarchy between the compositeness and the electroweak scale is introduced by the Collective Symmetry Breaking mechanism: one-loop diagrams generating the Higgs mass term are forced to be at most logarithmically sensitive to Λ. A naturally light Higgs boson can thus be accommodated, consistently with a perturbative theory until a scale of order 10 TeV. We have probed the parameter space of three prominent examples of Little Higgs models, namely the Simplest Little Higgs model, the Littlest Higgs model, and the Littlest Higgs model with T-parity, against electroweak precision observables and the collected LHC data concerning both Higgs properties and direct searches for new particles, with √(s)=7,8 TeV and up to 25 fb -1 of integrated luminosity. Lower bounds on the scale f are set, within a certain degree of confidence level, which allow to draw conclusions on the ''naturalness'' of the different models. Optimisations of the existing direct searches setups, assuming a Little Higgs signal, as well as dedicated mass measurement methods designed for the foreseen LHC runs with √(s)=13,14 TeV are thoroughly discussed and proposed in this thesis. Special attention will be dedicated to final states including either a large or negligible fraction of missing transverse momentum. In particular, we will propose a dedicated collider search tailored for the discovery and mass measurement of a top partner, exploiting jet

  6. A Higgs-bozon

    CERN Document Server

    Dezso, Horvath

    2017-01-01

    A részecskefizika általánosan elfogadott és az elmúlt 40 év alatt sokszorosan igazolt elmélete, a standard modell valamennyi alkatrészét sikerült megfigyelni és tanulmányozni a Higgs-bozon kivételével. A CERN nagy hadronütköztetője (LHC), a világ legnagyobb részecskegyorsítója is elsősorban a Higgs-részecske kimutatására épült. 2012 közepére az LHC két óriási mérőberendezése, a sok ezer fizikus részvételével épült CMS és ATLAS megfigyelt egy - a Higgs-bozon elméletileg megjósolt tulajdonságaival rendelkező - új részecskét. A könyv áttekinti a standard modell elméletét és a Higgs-részecske feltételezett tulajdonságait, majd összefoglalja az LHC Higgs-keresési eredményeit és a hozzájuk vezető utat. Függelékben ismerteti a könyvben előforduló fizikusok életrajzát és bizonyos fizikai fogalmak részletesebb leírását. A 2013-as fizikai Nobel-díjat Peter Higgs és François Englert kapták megosztva a Higgs-mechanizmus és a Higgs-bozon elmé...

  7. Too big for Higgs

    CERN Multimedia

    Hawkes, N

    1999-01-01

    A conference in the US has suggested that the mass of the Higgs boson may not be as large as previously thought. It may be within the reach of the Tevatron at Fermilab if it operates for longer than the planned two years. If so, the LHC designed specifically to find the Higgs boson may be beaten to the discovery before it is even built (1/2 page).

  8. Calculations of multi-particle processes at the one-loop level: precise predictions for the LHC

    International Nuclear Information System (INIS)

    Karg, Stefan

    2007-01-01

    We present a calculation of the loop-induced processes gg→HH and gg→HHH, and investigate the observability of multi-Higgs boson production at the LHC in the Standard Model and beyond. While the SM cross sections are too small to allow observation at the LHC, we demonstrate that physics beyond the SM can lead to amplified, observable cross sections. Furthermore, the applicability of the heavy top quark approximation in two- and three-Higgs boson production is investigated. The calculation of the process PP→VV+jet at NLO is an important background process to Higgs production in association with a jet at the LHC. We compute the virtual corrections to this process which form the ''bottleneck'' for obtaining a complete NLO prediction. The resulting analytic expressions are generated with highly automated computer routines and translated into a flexible Fortran code, which can be employed in the computation of differential cross sections of phenomenological interest. (orig.)

  9. Phenomenology of R-parity violating minimal supergravity

    International Nuclear Information System (INIS)

    Bernhardt, M.A.

    2008-02-01

    We investigate in detail the low-energy spectrum of the P 6 violating minimal supergravity model using the SOFTSUSY spectrum code. We impose the experimental constraints from the measurement of the anomalous magnetic moment of the muon (g-2) μ , the b→sγ decay, the branching ration of B s →μ + μ - , as well as the mass bound from direct searches at colliders, in particular the Higgs boson and the lightest Chargino. We focus on regions, where the lightest neutralino is not the lightest supersymmetric particle (LSP). In these regions of parameter space either the lightest scalar tau or one of the sneutrinos is the LSP. We suggest four benchmark points with typical spectra and novel collider signatures which we investigate with a parton level Monte-Carlo simulation. We give an outlook for their detailed phenomenological analysis and simulation by the LHC collaborations, then including detector effects. In addition, we discuss a full Monte-Carlo simulation for single slepton production in association with a single top quark via an LQD type operator at the hadron colliders LHC and Tevatron. We present these results and show a predicted range of detectability for this process- for small couplings in various minimal supergravity models at the LHC. (orig.)

  10. Phenomenology of R-parity violating minimal supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Bernhardt, M.A.

    2008-02-15

    We investigate in detail the low-energy spectrum of the P{sub 6} violating minimal supergravity model using the SOFTSUSY spectrum code. We impose the experimental constraints from the measurement of the anomalous magnetic moment of the muon (g-2){sub {mu}}, the b{yields}s{gamma} decay, the branching ration of B{sub s}{yields}{mu}{sup +}{mu}{sup -}, as well as the mass bound from direct searches at colliders, in particular the Higgs boson and the lightest Chargino. We focus on regions, where the lightest neutralino is not the lightest supersymmetric particle (LSP). In these regions of parameter space either the lightest scalar tau or one of the sneutrinos is the LSP. We suggest four benchmark points with typical spectra and novel collider signatures which we investigate with a parton level Monte-Carlo simulation. We give an outlook for their detailed phenomenological analysis and simulation by the LHC collaborations, then including detector effects. In addition, we discuss a full Monte-Carlo simulation for single slepton production in association with a single top quark via an LQD type operator at the hadron colliders LHC and Tevatron. We present these results and show a predicted range of detectability for this process- for small couplings in various minimal supergravity models at the LHC. (orig.)

  11. Higgs Physics at CLIC

    CERN Document Server

    AUTHOR|(CDS)2073690

    2016-01-01

    The Compact Linear Collider (CLIC) is an attractive option for a future multi-TeV linear electron-positron collider, offering the potential for a rich precision physics programme, combined with sensitivity to a wide range of new phenomena. The physics reach of CLIC has been studied in the context of three distinct centre-of-mass energies, √s = 350 GeV, 1.4 TeV and 3.0 TeV. This staged scenario provides an excellent environment for precise studies of the properties of the 126 GeV Higgs boson. Operation at √s = 350 GeV allows, on the one hand, for a determination of the couplings and width of the Higgs boson in a model-independent manner through the study of the Higgsstrahlung process, and on the other hand, for a study of Higgs bosons produced in W+W− fusion for the most common Higgs decay modes. Operation at higher centre-of-mass energies, √s = 1.4 TeV and 3 TeV, provides high statistics W+W− fusion samples allowing for high precision measurements of many Higgs couplings and a study of rare Higgs de...

  12. Statistical methods and the Higgs at 115 GeV at LEP; Methodes statistiques et le Higgs a 115 GeV au LEP

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, P

    2001-07-01

    The purpose of these lectures is to give the means to understand the results provided by the Higgs working group (HWG) that combines data from 4 experiments concerning the search for the Higgs boson at LEP. The first part deals with experimental analysis, it means phenomenology and how to select the interesting events. In the second part, the author presents statistical methods and statistical tools that are used to process data, it is shown that combining different analyses may increase the sensitivity level. The third part is dedicated to the situation at the LEP concerning the search for the Higgs boson by July 2001. Data are consistent for either a standard Higgs at around 115.6 GeV or a minimal supersymmetric model scenario.

  13. Electroweak symmetry breaking in supersymmetric gauge-Higgs unification models

    International Nuclear Information System (INIS)

    Choi, Kiwoon; Jeong, Kwang-Sik; Okumura, Ken-ichi; Haba, Naoyuki; Shimizu, Yasuhiro; Yamaguchi, Masahiro

    2004-01-01

    We examine the Higgs mass parameters and electroweak symmetry breaking in supersymmetric orbifold field theories in which the 4-dimensional Higgs fields originate from higher-dimensional gauge supermultiplets. It is noted that such gauge-Higgs unification leads to a specific boundary condition on the Higgs mass parameters at the compactification scale, which is independent of the details of supersymmetry breaking mechanism. With this boundary condition, phenomenologically viable parameter space of the model is severely constrained by the condition of electroweak symmetry breaking for supersymmetry breaking scenarios which can be realized naturally in orbifold field theories. For instance, if it is assumed that the 4-dimensional effective theory is the minimal supersymmetric standard model with supersymmetry breaking parameters induced by the Scherk-Schwarz mechanism, a correct electroweak symmetry breaking can not be achieved for reasonable range of parameters of the model, even when one includes additional contributions to the Higgs mass parameters from the auxiliary component of 4-dimensional conformal compensator. However if there exists a supersymmetry breaking mediated by brane superfields, sizable portion of the parameter space can give a correct electroweak symmetry breaking. (author)

  14. Doubling Up on Supersymmetry in the Higgs Sector

    CERN Document Server

    Ellis, John; Sanz, Verónica

    2016-10-17

    We explore the possibility that physics at the TeV scale possesses approximate $N = 2$ supersymmetry, which is reduced to the $N=1$ minimal supersymmetric extension of the Standard Model (MSSM) at the electroweak scale. This doubling of supersymmetry modifies the Higgs sector of the theory, with consequences for the masses, mixings and couplings of the MSSM Higgs bosons, whose phenomenological consequences we explore in this paper. The mass of the lightest neutral Higgs boson $h$ is independent of $\\tan \\beta$ at the tree level, and the decoupling limit is realized whatever the values of the heavy Higgs boson masses. Radiative corrections to the top quark and stop squarks dominate over those due to particles in $N=2$ gauge multiplets. We assume that these radiative corrections fix $m_h \\simeq 125$ GeV, whatever the masses of the other neutral Higgs bosons $H, A$, a scenario that we term the $h$2MSSM. Since the $H, A$ bosons decouple from the $W$ and $Z$ bosons in the $h$2MSSM at tree level, only the LHC const...

  15. Low-Data Investigation of Higgs Boson Discovery at the LHC

    OpenAIRE

    Scoby, Cheyne M

    2006-01-01

    The Standard Model (SM) remains as a complete and effective tool for understanding fundamental particles and their interactions. There is only one particle that the model predicts that has not yet been discovered. The Higgs boson is required as part of the mechanism behind electroweak symmetry breaking, and explains how the weak vector bosons, as well as the charged quarks and leptons gain mass, proportional to their coupling to the Higgs field. The SM predicts many properties of the Higgs, b...

  16. Phenomenology and homeopathy.

    Science.gov (United States)

    Whitmarsh, Tom

    2013-07-01

    There is a great overlap between the way of seeing the world in clinical homeopathy and in the technical philosophical system known as phenomenology. A knowledge of phenomenologic principles reveals Hahnemann to have been an unwitting phenomenologist. The ideas of phenomenology as applied to medicine show that homeopathy is the ideal medical system to fulfill the goals of coming ever closer to true patient concerns and experience of illness. Copyright © 2013 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  17. QCD evolution of (un)polarized gluon TMDPDFs and the Higgs q T -distribution

    Science.gov (United States)

    Echevarria, Miguel G.; Kasemets, Tomas; Mulders, Piet J.; Pisano, Cristian

    2015-07-01

    We provide the proper definition of all the leading-twist (un)polarized gluon transverse momentum dependent parton distribution functions (TMDPDFs), by considering the Higgs boson transverse momentum distribution in hadron-hadron collisions and deriving the factorization theorem in terms of them. We show that the evolution of all the (un)polarized gluon TMDPDFs is driven by a universal evolution kernel, which can be resummed up to next-to-next-to-leading-logarithmic accuracy. Considering the proper definition of gluon TMDPDFs, we perform an explicit next-to-leading-order calculation of the unpolarized ( f {1/ g }), linearly polarized ( h {1/⊥ g }) and helicity ( g {1/L g }) gluon TMDPDFs, and show that, as expected, they are free from rapidity divergences. As a byproduct, we obtain the Wilson coefficients of the refactorization of these TMDPDFs at large transverse momentum. In particular, the coefficient of g {1/L g }, which has never been calculated before, constitutes a new and necessary ingredient for a reliable phenomenological extraction of this quantity, for instance at RHIC or the future AFTER@LHC or Electron-Ion Collider. The coefficients of f {1/ g } and h {1/⊥ g } have never been calculated in the present formalism, although they could be obtained by carefully collecting and recasting previous results in the new TMD formalism. We apply these results to analyze the contribution of linearly polarized gluons at different scales, relevant, for instance, for the inclusive production of the Higgs boson and the C-even pseudoscalar bottomonium state η b . Applying our resummation scheme we finally provide predictions for the Higgs boson q T -distribution at the LHC.

  18. SM Higgs decay branching ratios and total Higgs width

    CERN Multimedia

    Daniel Denegri

    2001-01-01

    Upper: Higgs decay ratios as a function of Higgs mass. The largest branching ratio is not necessarily the most usefull one. The most usefull ones are gamma gamma bbar ZZ and WW as in those modes latter signal to background ratios can be achieved. Lower: Total Higgs decay width versus Higgs mass. At low masses the natural width is extremely small, thus observability depends on instrumental resolution primarily.

  19. Working Group Report: Higgs Boson

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Sally; Gritsan, Andrei; Logan, Heather; Qian, Jianming; Tully, Chris; Van Kooten, Rick [et al.

    2013-10-30

    This report summarizes the work of the Energy Frontier Higgs Boson working group of the 2013 Community Summer Study (Snowmass). We identify the key elements of a precision Higgs physics program and document the physics potential of future experimental facilities as elucidated during the Snowmass study. We study Higgs couplings to gauge boson and fermion pairs, double Higgs production for the Higgs self-coupling, its quantum numbers and $CP$-mixing in Higgs couplings, the Higgs mass and total width, and prospects for direct searches for additional Higgs bosons in extensions of the Standard Model. Our report includes projections of measurement capabilities from detailed studies of the Compact Linear Collider (CLIC), a Gamma-Gamma Collider, the International Linear Collider (ILC), the Large Hadron Collider High-Luminosity Upgrade (HL-LHC), Very Large Hadron Colliders up to 100 TeV (VLHC), a Muon Collider, and a Triple-Large Electron Positron Collider (TLEP).

  20. Higgs boson transverse momentum distribution

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    I will review  the recent progress in understanding Higgs boson transverse momentum distribution focusing on effects that go beyond the point-like approximation for the Higgs-glue interaction vertex.

  1. Deuteron stripping reactions using dirac phenomenology

    Science.gov (United States)

    Hawk, E. A.; McNeil, J. A.

    2001-04-01

    In this work deuteron stripping reactions are studied using the distorted wave born approximation employing dirac phenomenological potentials. In 1982 Shepard and Rost performed zero-range dirac phenomenological stripping calculations and found a dramatic reduction in the predicted cross sections when compared with similar nonrelativistic calculations. We extend the earlier work by including full finite range effects as well as the deuteron's internal D-state. Results will be compared with traditional nonrelativistic approaches and experimental data at low energy.

  2. Higgs bosons in the standard model, the МssМ and beyond

    Indian Academy of Sciences (India)

    I summarize the basic theory and selected phenomenology for the Higgs bo- ... The most immediate goal of the present and future colliders will be to discover ...... cluded domains lie at high m (for which decoupling is setting in) and high tanβ.

  3. Search for hidden Higgs decay in ATLAS detector

    International Nuclear Information System (INIS)

    Gabrielli, A.

    2013-01-01

    In this paper, a brief overview of the search for the Higgs boson in Hidden Valley models is given. Hidden Valley models predict Higgs decays to neutral particles, which can be also long lived with decay paths comparable to the LHC detectors dimensions. Decay final states consist of collimated leptons (Lepton Jets). Results are presented of a search for Higgs decays to long lived particles in the ATLAS detector at the LHC, based on 1.92 fb −1 data collected during 2011 at a 7TeV center-of-mass energy.

  4. Phenomenology of supersymmetry with scalar sequestering

    International Nuclear Information System (INIS)

    Perez, Gilad; Roy, Tuhin S.; Schmaltz, Martin

    2009-01-01

    The defining feature of scalar sequestering is that the minimal supersymmetric standard model squark and slepton masses as well as all entries of the scalar Higgs mass matrix vanish at some high scale. This ultraviolet boundary condition--scalar masses vanish while gaugino and Higgsino masses are unsuppressed--is independent of the supersymmetry breaking mediation mechanism. It is the result of renormalization group scaling from approximately conformal strong dynamics in the hidden sector. We review the mechanism of scalar sequestering and prove that the same dynamics which suppresses scalar soft masses and the B μ term also drives the Higgs soft masses to -|μ| 2 . Thus the supersymmetric contribution to the Higgs mass matrix from the μ term is exactly canceled by the soft masses. Scalar sequestering has two tell-tale predictions for the superpartner spectrum in addition to the usual gaugino mediation predictions: Higgsinos are much heavier (μ > or approx. TeV) than scalar Higgses (m A ∼few hundred GeV), and third generation scalar masses are enhanced because of new positive contributions from Higgs loops.

  5. Tools for charged Higgs bosons

    International Nuclear Information System (INIS)

    Staal, Oscar

    2010-12-01

    We review the status of publicly available software tools applicable to charged Higgs physics. A selection of codes are highlighted in more detail, focusing on new developments that have taken place since the previous charged Higgs workshop in 2008. We conclude that phenomenologists now have the tools ready to face the LHC data. A new web page collecting charged Higgs resources is presented. (orig.)

  6. Finite-Temperature Higgs Potentials

    International Nuclear Information System (INIS)

    Dolgopolov, M.V.; Gurskaya, A.V.; Rykova, E.N.

    2016-01-01

    In the present article we consider the short description of the “Finite-Temperature Higgs Potentials” program for calculating loop integrals at vanishing external momenta and applications for extended Higgs potentials reconstructions. Here we collect the analytic forms of the relevant loop integrals for our work in reconstruction of the effective Higgs potential parameters in extended models (MSSM, NMSSM and etc.)

  7. Phenomenology of the spontaneous C P violation in SU(3)L x U(1)Y electroweak models

    International Nuclear Information System (INIS)

    Epele, Luis N.; Gomez Dumm, Daniel A.

    1994-01-01

    This work studies the phenomenological consequence of the spontaneous C P violation in a SU(3) L x U(1) Y model with three Higgs triplets and one sextuplet, which has been recently proposed. Since this C P-violating effects are due to the presence of complex vacuum expectation values in the Higgs sector, our analysis requires a detailed study of the enlarged potential

  8. Phenomenology and Meaning Attribution

    African Journals Online (AJOL)

    John Paley. (2017). Phenomenology as Qualitative Research: A Critical Analysis of Meaning Attribution. ... basic philosophical nature of phenomenological meaning and inquiry, and that he not ... In keeping with the title of my book, Researching. Lived Experience ...... a quantitative social science that can make generalizing.

  9. What Is Film Phenomenology?

    NARCIS (Netherlands)

    Hanich, Julian; Ferencz-Flatz, Christian

    2016-01-01

    In this article Christian Ferencz-Flatz and I try to give an answer to the question what film phenomenology actually is. We proceed in three steps. First, we provide a survey of five different research practices within current film phenomenological writing: We call them excavation, explanation,

  10. Qui attrapera le Higgs?

    CERN Multimedia

    Colas, Paul

    2003-01-01

    The Higgs boson was theoretically created about 40 years ago by a Scott Peter Higgs who wanted to explain why some particles get a mass. Since then the Higgs boson has taken consistency and has become an important point of the standard model theory. Its experimental discovery would be a milestone of modern physics. The search for the Higgs boson is an international challenge that takes place around 2 huge machines: the Tevatron near Chicago and the LHC (large hadron collider) that is being built in CERN. The Tevatron is in fact the upgrading of an old particle accelerator, it is a proton collider and its narrow range of energy is compensated by a low background noise. On the other hand the LHC will begin operating only in 2007 and its full power will be reached a few years later, the energy available to create particles will be then 7 times higher than for the Tevatron. Both machines have chance of succeeding by being the first to detect the Higgs boson. Time plays in favor of the Tevatron but in any case if ...

  11. Gauge-Higgs unification with brane kinetic terms

    International Nuclear Information System (INIS)

    Aranda, Alfredo; Diaz-Cruz, J. Lorenzo

    2006-01-01

    By identifying the Higgs field as an internal component of a higher-dimensional gauge field it is possible to solve the little hierarchy problem. The construction of a realistic model that incorporates such a gauge-Higgs unification is an important problem that demands attention. In fact, several attempts in this direction have already been put forward. In this Letter we single out one such attempt, a 6D SU(3) extended electroweak theory, where it is possible to obtain a Higgs mass prediction in accord with global fits. One shortcoming of the model is its prediction for the Weinberg angle, it is too large. We slightly modify the model by including brane kinetic terms in a way motivated by the orbifold action on the 6D fields. We show that in this way it is possible to obtain the correct Weinberg angle while keeping the desired results in the Higgs sector

  12. Searches for Higgs and Higgs-like particles at LHCb

    CERN Document Server

    Kucharczyk, Marcin

    2014-01-01

    A set of results related to the new particles searches in LHCb are reported. Upper limits on the cross section times branching fraction of neutral Higgs bos on decaying into two tau leptons have been set in the model independent search and in the Minimal Su persymmetric Model. Many theo- retical models predict the existence of the Higgs bosons dec aying into heavy long-lived particles. The upper limit on their production cross section has been de termined for several combinations of parameters. A measurement of the cross section for the produ ction of b ̄ b and c ̄ c pairs based on in- clusive final states has been performed in a region of pseudor apidity 2.5 5 GeV of the b hadron candidate, resulting in σ ( b ̄ b ) = 7.7 ± 0.12 (stat) ± 0.84 (syst) and σ ( c ̄ c ) = 104.6 ± 2.7 (stat) ± 11.4 (syst). The forward-central b ̄ b production asymme- try, based on the selection of high p T jet pairs tagged by the presence of a displaced muon with high momentum, has been determined to be A b ̄ b FC = (0...

  13. Searches for Higgs and Higgs-like particles at LHCb

    CERN Document Server

    AUTHOR|(SzGeCERN)477437

    2013-01-01

    A set of results related to the new particles searches in LHCb are reported. Upper limits on the cross section times branching fraction of neutral Higgs boson decaying into two tau leptons have been set in the model independent search and in the Minimal Supersymmetric Model. Many theoretical models predict the existence of the Higgs bosons decaying into heavy long-lived particles. The upper limit on their production cross section has been determined for several combinations of parameters. A measurement of the cross section for the production of $b\\overline{b}$ and $c\\overline{c}$ pairs based on inclusive final states has been performed in a region of pseudorapidity 2.5 5 GeV of the $b$ hadron candidate, resulting in $\\sigma$ $(b\\overline{b})$ = $7.7 \\pm 0.12 (stat) \\pm 0.84 (syst)$ and $\\sigma$ $(c\\overline{c})$ = $104.6 \\pm 2.7 (stat) \\pm 11.4 (syst)$. The forward-central $b\\overline{b}$ production asymmetry, based on the selection of high $p_T$ jet pairs tagged by the presence of a displaced muon with hig...

  14. Il Bosone di Higgs

    CERN Multimedia

    Hemmer, Sabine

    2018-01-01

    Poster di ATLAS sul bosone di Higgs indirizzato al pubblico generico, che spiega il meccanismo di Brout-Englert-Higgs e la sua importanza. Spiega anche il ruolo del Bosone di Higgs, come viene cercato, il percorso della sua scoperta e cosa viene dopo la scoperta. Disponibile anche in Francese (http://cds.cern.ch/record/1697501) e Inglese (http://cds.cern.ch/record/1697389). Non esitate a utilizzarlo nelle sedi dei vostri Istituti e negli eventi divulgativi! Il poster è in formato A0. Cliccate sull'immagine per scaricare il .pdf ad alta qualità e stamparlo dove preferite. Per qualisasi domanda o commento potete contattare atlas-outreach-coordination@cern.ch

  15. Higgs searches with CMS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    The excellent performances of the LHC in the 2011 run are setting the grounds for the final chase of the Higgs boson. The CMS experiment is recording high quality data that are being thoroughly scrutinized. Several decay channels are investigated to probe the entire possible Higgs mass spectrum, from 110 to 600 GeV/c^2. The study of the first 1.5/fb of collected data places already tight limits and excludes large fractions of the Higgs mass range, leaving however still open the search in the theoretically favored low mass region. In this seminar we will report on the diverse CMS analyses that yield to such results describing the experimental challenges that each had to meet.

  16. The Higgs boson

    CERN Multimedia

    Brunet, S

    2014-01-01

    ATLAS Higgs poster targeted to general public, explaining the Brout-Englert-Higgs mechanism and why it is important. It also explains the role of the Higgs Boson, how we look for it, the journey of the discovery and what comes after the discovery. Also available in French (http://cds.cern.ch/record/1697501). Don’t hesitate to use it in your institute’s corridors and in your outreach events! The poster is in A0 format. You can click on the image to download the high-quality .pdf version and print it at your favorite printshop. For any questions or comments you can contact atlas-outreach-coordination@cern.ch.

  17. Higgs boson as a top-mode pseudo-Nambu-Goldstone boson

    Science.gov (United States)

    Fukano, Hidenori S.; Kurachi, Masafumi; Matsuzaki, Shinya; Yamawaki, Koichi

    2014-09-01

    In the spirit of the top-quark condensation, we propose a model which has a naturally light composite Higgs boson, "tHiggs" (ht0), to be identified with the 126 GeV Higgs discovered at the LHC. The tHiggs, a bound state of the top quark and its flavor (vectorlike) partner, emerges as a pseudo-Nambu-Goldstone boson (NGB), "top-mode pseudo-Nambu-Goldstone boson," together with the exact NGBs to be absorbed into the W and Z bosons as well as another (heavier) top-mode pseudo-Nambu-Goldstone bosons (CP-odd composite scalar, At0). Those five composite (exact/pseudo-) NGBs are dynamically produced simultaneously by a single supercritical four-fermion interaction having U(3)×U(1) symmetry which includes the electroweak symmetry, where the vacuum is aligned by a small explicit breaking term so as to break the symmetry down to a subgroup, U(2)×U(1)', in a way not to retain the electroweak symmetry, in sharp contrast to the little Higgs models. The explicit breaking term for the vacuum alignment gives rise to a mass of the tHiggs, which is protected by the symmetry and hence naturally controlled against radiative corrections. Realistic top-quark mass is easily realized similarly to the top-seesaw mechanism by introducing an extra (subcritical) four-fermion coupling which explicitly breaks the residual U(2)'×U(1)' symmetry with U(2)' being an extra symmetry besides the above U(3)L×U(1). We present a phenomenological Lagrangian of the top-mode pseudo-Nambu-Goldstone bosons along with the Standard Model particles, which will be useful for the study of the collider phenomenology. The coupling property of the tHiggs is shown to be consistent with the currently available data reported from the LHC. Several phenomenological consequences and constraints from experiments are also addressed.

  18. Higgs potential and spinor connection within Weinberg-Salam model

    International Nuclear Information System (INIS)

    Trostel, R.

    1987-01-01

    We arrive at a theory of the Higgs potential by extending the usual concept of the covariant derivative containing the gauge fields to one which also contains the Higgs fields, by using a spinor connection compatible under local gauge transformations. Not only the Yukawa couplings are geometrized by this procedure but also the nonlinear Higgs potential naturally appears within the curvature of the corresponding spinor connection. Taking the gauge group to be SU(2) x U(1), we arrive for the leptonic Weinberg Salam model at a Weinberg angle prediction of sin 2 θ=1/4 and at a Higgs mass of about 263-270 GeV without using any supersymmetry argument. Taking the gauge group to be SU(3) C x SU(2) x U(1) the above leptonic result is obtained only if e 2 /g S 2 is sufficiently small, which is approximately true. Working with two independent Higgs doublets we arrive at a Higgs mass sum rule, where two Higgs must have a mass of about 188 GeV. (author)

  19. Higgs for the masses

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-03-15

    The unified theory of electromagnetism and the weak nuclear force, crowned with the discovery at CERN in 1983 of the W and Z bosons which carry the weak nuclear force, is one of the great triumphs of modern physics. But the picture is not yet complete. An essential but still elusive ingredient is the so-called 'Higgs boson' (after Edinburgh theorist Peter Higgs), responsible for the vital symmetry breaking in the theory. This gives the carriers of the weak force mass, while the photon, the carrier of electromagnetism, is massless.

  20. Discovery of the Higgs boson by the ATLAS and CMS experiments at the LHC

    CERN Document Server

    Wang, HaiChen

    2014-01-01

    The Standard Model (SM) Higgs boson was predicted by theorists in the 1960s during the development of the electroweak theory. Prior to the startup of the CERN Large Hadron Collider (LHC), experimental searches found no evidence of the Higgs boson. In July 2012, the ATLAS and CMS experiments at the LHC reported the discovery of a new boson in their searches for the SM Higgs boson. Subsequent experimental studies have revealed the spin-0 nature of this new boson and found its couplings to SM particles consistent to those of a Higgs boson. These measurements confirmed the newly discovered boson is indeed a Higgs boson. More measurements will be performed to compare the properties of the Higgs boson with the SM predictions.

  1. Bound states via Higgs exchanging and heavy resonant di-Higgs

    Directory of Open Access Journals (Sweden)

    Zhaofeng Kang

    2017-08-01

    Full Text Available The existence of Higgs boson h predicted by the standard model (SM was established and hunting for clues to new physics (NP hidden in h has become the top priority in particle physics. In this paper we explore an intriguing phenomenon that prevails in NP associated with h, bound state (Bh, referring to the ground state only of relatively heavy particles ϕ out of NP via interchanging h. This is well-motivated due to the intrinsic properties of h: It has zero spin and light mass, capable of mediating Yukawa interactions; moreover, it may be strongly coupled to ϕ in several important contexts, from addressing the naturalness problem by compositeness/supersymmetry (SUSY/classical scale invariance to understanding neutrino mass origin radiatively and matter asymmetry by electroweak baryogensis. The new resonance Bh, being a neutral scalar boson, has important implications to the large hadron collider (LHC di-Higgs search because it yields a clear resonant di-Higgs signature at the high mass region (≳1 TeV. In other words, searching for Bh offers a new avenue to probe the hidden sector with a Higgs-portal. For illustration in this paper we concentrate on two examples, the stop sector in SUSY and an inert Higgs doublet from a radiative neutrino model. In particular, h-mediation opens a new and wide window to probe the conventional stoponium and the current date begins to have sensitivity to stoponium around TeV.

  2. Bound states via Higgs exchanging and heavy resonant di-Higgs

    Science.gov (United States)

    Kang, Zhaofeng

    2017-08-01

    The existence of Higgs boson h predicted by the standard model (SM) was established and hunting for clues to new physics (NP) hidden in h has become the top priority in particle physics. In this paper we explore an intriguing phenomenon that prevails in NP associated with h, bound state (Bh, referring to the ground state only) of relatively heavy particles ϕ out of NP via interchanging h. This is well-motivated due to the intrinsic properties of h: It has zero spin and light mass, capable of mediating Yukawa interactions; moreover, it may be strongly coupled to ϕ in several important contexts, from addressing the naturalness problem by compositeness/supersymmetry (SUSY)/classical scale invariance to understanding neutrino mass origin radiatively and matter asymmetry by electroweak baryogensis. The new resonance Bh, being a neutral scalar boson, has important implications to the large hadron collider (LHC) di-Higgs search because it yields a clear resonant di-Higgs signature at the high mass region (≳ 1 TeV). In other words, searching for Bh offers a new avenue to probe the hidden sector with a Higgs-portal. For illustration in this paper we concentrate on two examples, the stop sector in SUSY and an inert Higgs doublet from a radiative neutrino model. In particular, h-mediation opens a new and wide window to probe the conventional stoponium and the current date begins to have sensitivity to stoponium around TeV.

  3. Distinguishing Little-Higgs product and simple group models at the LHC and ILC

    International Nuclear Information System (INIS)

    Kilian, W.; Rainwater, D.

    2006-09-01

    We propose a means to discriminate between the two basic variants of Little Higgs models, the Product Group and Simple Group models, at the next generation of colliders. It relies on a special coupling of light pseudoscalar particles present in Little Higgs models, the pseudo-axions, to the Z and the Higgs boson, which is present only in Simple Group models. We discuss the collider phenomenology of the pseudo-axion in the presence of such a coupling at the LHC, where resonant production and decay of either the Higgs or the pseudo-axion induced by that coupling can be observed for much of parameter space. The full allowed range of parameters, including regions where the observability is limited at the LHC, is covered by a future ILC, where double scalar production would be a golden channel to look for. (orig.)

  4. Distinguishing Little-Higgs product and simple group models at the LHC and ILC

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, W. [Siegen Univ. (Gesamthochschule) (Germany). Fachbereich 7 - Physik]|[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Rainwater, D. [Rochester Univ., NY (United States). Dept. of Physics and Astronomy; Reuter, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-09-15

    We propose a means to discriminate between the two basic variants of Little Higgs models, the Product Group and Simple Group models, at the next generation of colliders. It relies on a special coupling of light pseudoscalar particles present in Little Higgs models, the pseudo-axions, to the Z and the Higgs boson, which is present only in Simple Group models. We discuss the collider phenomenology of the pseudo-axion in the presence of such a coupling at the LHC, where resonant production and decay of either the Higgs or the pseudo-axion induced by that coupling can be observed for much of parameter space. The full allowed range of parameters, including regions where the observability is limited at the LHC, is covered by a future ILC, where double scalar production would be a golden channel to look for. (orig.)

  5. Implications of improved Higgs mass calculations for supersymmetric models.

    Science.gov (United States)

    Buchmueller, O; Dolan, M J; Ellis, J; Hahn, T; Heinemeyer, S; Hollik, W; Marrouche, J; Olive, K A; Rzehak, H; de Vries, K J; Weiglein, G

    We discuss the allowed parameter spaces of supersymmetric scenarios in light of improved Higgs mass predictions provided by FeynHiggs 2.10.0. The Higgs mass predictions combine Feynman-diagrammatic results with a resummation of leading and subleading logarithmic corrections from the stop/top sector, which yield a significant improvement in the region of large stop masses. Scans in the pMSSM parameter space show that, for given values of the soft supersymmetry-breaking parameters, the new logarithmic contributions beyond the two-loop order implemented in FeynHiggs tend to give larger values of the light CP-even Higgs mass, [Formula: see text], in the region of large stop masses than previous predictions that were based on a fixed-order Feynman-diagrammatic result, though the differences are generally consistent with the previous estimates of theoretical uncertainties. We re-analyse the parameter spaces of the CMSSM, NUHM1 and NUHM2, taking into account also the constraints from CMS and LHCb measurements of [Formula: see text]and ATLAS searches for [Formula: see text] events using 20/fb of LHC data at 8 TeV. Within the CMSSM, the Higgs mass constraint disfavours [Formula: see text], though not in the NUHM1 or NUHM2.

  6. Implications of improved Higgs mass calculations for supersymmetric models

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, O. [Imperial College, London (United Kingdom). High Energy Physics Group; Dolan, M.J. [SLAC National Accelerator Laboratory, Menlo Park, CA (United States). Theory Group; Ellis, J. [King' s College, London (United Kingdom). Theoretical Particle Physics and Cosmology Group; and others

    2014-03-15

    We discuss the allowed parameter spaces of supersymmetric scenarios in light of improved Higgs mass predictions provided by FeynHiggs 2.10.0. The Higgs mass predictions combine Feynman-diagrammatic results with a resummation of leading and subleading logarithmic corrections from the stop/top sector, which yield a significant improvement in the region of large stop masses. Scans in the pMSSM parameter space show that, for given values of the soft supersymmetry-breaking parameters, the new logarithmic contributions beyond the two-loop order implemented in FeynHiggs tend to give larger values of the light CP-even Higgs mass, M{sub h}, in the region of large stop masses than previous predictions that were based on a fixed-order Feynman-diagrammatic result, though the differences are generally consistent with the previous estimates of theoretical uncertainties. We re-analyze the parameter spaces of the CMSSM, NUHM1 and NUHM2, taking into account also the constraints from CMS and LHCb measurements of BR(B{sub s}→μ{sup +}μ{sup -}) and ATLAS searches for E{sub T} events using 20/fb of LHC data at 8 TeV. Within the CMSSM, the Higgs mass constraint disfavours tan β

  7. Two Higgs Bosons near 125 GeV in the Complex NMSSM and the LHC Run I Data

    International Nuclear Information System (INIS)

    Munir, Shoaib; Moretti, Stefano

    2015-01-01

    We analyse the impact of explicit CP-violation in the Higgs sector of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) on its consistency with the Higgs boson data from the Large Hadron Collider (LHC). Through detailed scans of the parameter space of the complex NMSSM for certain fixed values of one of its CP-violating (CPV) phases, we obtain a large number of points corresponding to five phenomenologically relevant scenarios containing ∼125 GeV Higgs boson(s). We focus, in particular, on the scenarios where the visible peaks in the experimental samples can actually be explained by two nearly mass-degenerate neutral Higgs boson states. We find that some points corresponding to these scenarios give an overall slightly improved fit to the data, more so for nonzero values of the CPV phase, compared to the scenarios containing a single Higgs boson near 125 GeV

  8. The search for associated Higgs boson production with Higgs decaying to bb in CMS

    CERN Document Server

    De Gruttola, Michele

    2013-01-01

    Results are presented on the study of a Higgs boson at 125 GeV decaying into final states consisting of b anti-b quark pair, based on the full statistics of about 25 fb$^{-1}$, collected in 2011 and 2012 at 7 and 8 TeV, respectively, with the CMS experiment. The $b \\bar{b}$ decay channel is studied in associated production with W/Z bosons and in the vector boson fusion process. The combination of the latest CMS $\\mathrm{H}\\rightarrow b \\bar{b}$ search for a mass of 125 GeV is an excess of observed events of 2.1 standard deviations, and is consistent with the standard model prediction for Higgs boson production. The observed signal strength corresponding to this excess is $1.0\\pm0.5$ relative to the standard model Higgs boson.

  9. The U(1)-Higgs model: critical behaviour in the confining-Higgs region

    International Nuclear Information System (INIS)

    Alonso, J.L.; Azcoiti, V.; Campos, I.; Ciria, J.C.; Cruz, A.; Iniguez, D.; Lesmes, F.; Piedrafita, C.; Rivero, A.; Tarancon, A.; Badoni, D.; Fernandez, L.A.; Munoz Sudupe, A.; Ruiz-Lorenzo, J.J.; Gonzalez-Arroyo, A.; Martinez, P.; Pech, J.; Tellez, P.

    1993-01-01

    We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and confining phases merge. We find evidence for a first-order transition line that ends in a second-order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and critical exponents in close resemblance with simple models that show analogous critical behaviour. The measured data allow us to fit the critical exponents finding values in agreement with the mean-field prediction. The location of the critical point and the slope of the first-order line are accurately measured. (orig.)

  10. Higgs boson production in the littlest Higgs model with T-parity at the ILC

    Science.gov (United States)

    Han, Jinzhong; Yang, Guang; Meng, Ming; Wang, Weijian; Li, Jingyun

    2018-04-01

    We investigate the Higgs boson production processes e+e‑→ ZH, e+e‑→ νν¯H, e+e‑→ tt¯H, e+e‑→ ZHH and e+e‑→ νν¯HH in the littlest Higgs model with T-parity (LHT) at the International Linear Collider (ILC). We calculate the LHT model predictions on the production rate of these processes at the ILC in the case of (un)polarized beams and the signal strengths of the production processes ZH and νν¯H with Higgs decaying to bb¯(gg,γγ). In the allowed parameter space, we find that the signal strengths μgg is most likely approach to the expected precision of the ILC.

  11. Phenomenological consequences of supersymmetry

    International Nuclear Information System (INIS)

    Hinchliffe, I.; Littenberg, L.

    1982-01-01

    This report deals with the phenomenological consequences of supersymmetric theories, and with the implications of such theories for future high energy machines. It is concerned only with high energy predictions of supersymmetry; low energy consequences (for example in the K/sub o/anti K/sub o/ system) are discussed in the context of future experiments by another group, and will be mentioned briefly only in the context of constraining existing models. However a brief section is included on the implication for proton decay, although detailed experimental questions are not discussed. The report is organized as follows. Section I consists of a brief review of supersymmetry and the salient features of existing supersymmetric models; this section can be ignored by those familiar with such models since it contains nothing new. Section 2 deals with the consequences for nucleon decay of SUSY. The remaining sections then discuss the physics possibilities of various machines; e anti e in Section 3, ep in Section 4, pp (or anti pp) colliders in Section 5 and fixed target hadron machines in Section 6

  12. Multifield dynamics in Higgs-otic inflation

    Energy Technology Data Exchange (ETDEWEB)

    Bielleman, S.; Ibáñez, L.E.; Pedro, F.G.; Valenzuela, I. [Departamento de Física Teórica UAM and Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain)

    2016-01-20

    In Higgs-otic inflation a complex neutral scalar combination of the h{sup 0} and H{sup 0} MSSM Higgs fields plays the role of inflaton in a chaotic fashion. The potential is protected from large trans-Planckian corrections at large inflaton if the system is embedded in string theory so that the Higgs fields parametrize a D-brane position. The inflaton potential is then given by a DBI+CS D-brane action yielding an approximate linear behaviour at large field. The inflaton scalar potential is a 2-field model with specific non-canonical kinetic terms. Previous computations of the cosmological parameters (i.e. scalar and tensor perturbations) did not take into account the full 2-field character of the model, ignoring in particular the presence of isocurvature perturbations and their coupling to the adiabatic modes. It is well known that for generic 2-field potentials such effects may significantly alter the observational signatures of a given model. We perform a full analysis of adiabatic and isocurvature perturbations in the Higgs-otic 2-field model. We show that the predictivity of the model is increased compared to the adiabatic approximation. Isocurvature perturbations moderately feed back into adiabatic fluctuations. However, the isocurvature component is exponentially damped by the end of inflation. The tensor to scalar ratio varies in a region r=0.08–0.12, consistent with combined Planck/BICEP results.

  13. Search for Charged Higgs in CDF

    Science.gov (United States)

    CDF Collaboration

    1996-05-01

    We present results of a search for charged Higgs production from pbarp collisions at √s=1.8 TeV at Fermilab's Tevatron collider using the CDF detector. An expanded Higgs sector containing charged Higgs bosons is a persistent feature of candidate theories to replace the Standard Model. The minimal supersymmetric extention of the Standard Model, for example, predicts that the dominant decay mode of the top quark is tarrow H+barrow τ+ν b for large values of tanβ. We use the hadronic decays of the tau lepton in this channel to set a new limit on charged Higgs production. *We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Science and Culture of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; and the A. P. Sloan Foundation. Supported by U.S. NSF NSF-94-17820.

  14. Elementary Goldstone Higgs Boson and Dark Matter

    DEFF Research Database (Denmark)

    Alanne, Tommi; Gertov, Helene; Sannino, Francesco

    2015-01-01

    We investigate a perturbative extension of the Standard Model featuring elementary pseudo-Goldstone Higgs and dark matter particles. These are two of the five Goldstone bosons parametrising the SU(4)/Sp(4) coset space. They acquire masses, and therefore become pseudo-Goldstone bosons, due...... of the theory, the quantum corrections are precisely calculable. The remaining pseudo-Goldstone boson is identified with the dark matter candidate because it is neutral with respect to the Standard Model and stable. By a direct comparison with the Large Hadron Collider experiments, the model is found...... to be phenomenologically viable. Furthermore the dark matter particle leads to the observed thermal relic density while respecting the most stringent current experimental constraints....

  15. Improved Limits for Higgs-Portal Dark Matter from LHC Searches.

    Science.gov (United States)

    Hoferichter, Martin; Klos, Philipp; Menéndez, Javier; Schwenk, Achim

    2017-11-03

    Searches for invisible Higgs decays at the Large Hadron Collider constrain dark matter Higgs-portal models, where dark matter interacts with the standard model fields via the Higgs boson. While these searches complement dark matter direct-detection experiments, a comparison of the two limits depends on the coupling of the Higgs boson to the nucleons forming the direct-detection nuclear target, typically parametrized in a single quantity f_{N}. We evaluate f_{N} using recent phenomenological and lattice-QCD calculations, and include for the first time the coupling of the Higgs boson to two nucleons via pion-exchange currents. We observe a partial cancellation for Higgs-portal models that makes the two-nucleon contribution anomalously small. Our results, summarized as f_{N}=0.308(18), show that the uncertainty of the Higgs-nucleon coupling has been vastly overestimated in the past. The improved limits highlight that state-of-the-art nuclear physics input is key to fully exploiting experimental searches.

  16. Higgs characterisation in the presence of theoretical uncertainties and invisible decays

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Christoph [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Kogler, Roman [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Schulz, Holger; Spannowsky, Michael [Durham University, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom)

    2017-11-15

    While the Higgs characterisation programme is well under way, direct signs for new physics beyond the Standard Model remain elusive. Performing a fit of fully differential Higgs production cross sections at the LHC to a subset of Higgs-relevant effective operators, we discuss the extent to which theoretical uncertainties can limit the sensitivity in such a new physics search programme. Extending the dimension-6 Higgs Effective Field Theory framework by introducing new light degrees of freedom that can contribute to an invisible (or undetectable) Higgs decay width h → φφ, we show how differential coupling fits can disentangle effects from non-Standard Model couplings and an invisible decay width, as present in many new physics scenarios, such as Higgs-portal dark matter. Including the so-called off-shell measurement that has been advocated as a sensitive determination of the Higgs width in the κ framework, we show explicitly that this method does not provide complementary sensitivity for scale-separated new physics Λ >> m{sub h} >> m{sub φ}, which is favoured in beyond the Standard Model scenarios that relate astrophysics and collider phenomenology in the light of non-observation of new physics during run 1 of the LHC. (orig.)

  17. Collider Probes of the MSSM Higgs Sector with Explicit CP Violation

    CERN Document Server

    Carena, M S; Mrenna, S; Pilaftsis, Apostolos; Wagner, C E M

    2003-01-01

    We investigate the hadron collider phenomenology of the Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation for Higgs bosons that can be observed in Standard Model search channels: W/ZH(->b-bbar) at the Tevatron, and gg->H(->gamma-gamma), t-tbar-H(->b-bbar) and WW->H(->tau+tau-) at the LHC. Our numerical analysis is based on a benchmark scenario proposed earlier called CPX, which has been designed to showcase the effects of CP violation in the MSSM, and on several variant benchmarks. In most of the CPX parameter space, these hadron colliders will find one of the neutral MSSM Higgs bosons. However, there are small regions of parameter space in which none of the neutral Higgs bosons can be detected in the standard channels at the Tevatron and the LHC. This occurs because the neutral Higgs boson with the largest coupling to W and Z bosons decays predominantly into either two lighter Higgs bosons or a Higgs boson and a gauge boson, whilst the lighter Higgs boson has only small couplings to the...

  18. B-meson anomalies and Higgs physics in flavored U(1)' model

    Science.gov (United States)

    Bian, Ligong; Lee, Hyun Min; Park, Chan Beom

    2018-04-01

    We consider a simple extension of the Standard Model with flavor-dependent U(1)', that has been proposed to explain some of B-meson anomalies recently reported at LHCb. The U(1)' charge is chosen as a linear combination of anomaly-free B_3-L_3 and L_μ -L_τ . In this model, the flavor structure in the SM is restricted due to flavor-dependent U(1)' charges, in particular, quark mixings are induced by a small vacuum expectation value of the extra Higgs doublet. As a result, it is natural to get sizable flavor-violating Yukawa couplings of heavy Higgs bosons involving the bottom quark. In this article, we focus on the phenomenology of the Higgs sector of the model including extra Higgs doublet and singlet scalars. We impose various bounds on the extended Higgs sector from Higgs and electroweak precision data, B-meson mixings and decays as well as unitarity and stability bounds, then discuss the productions and decays of heavy Higgs bosons at the LHC.

  19. Higgs! Wo steckst du?

    CERN Multimedia

    Hein, Till

    2005-01-01

    CERN's physicists are worried by a great question: does the universe remain stable? Why does the world exist? To answer, they look for the infinitely small and are trying to find the "key": the hypothetical Higgs-boson (4½ pages)

  20. APS Quantum Critical Higgs

    CERN Document Server

    Bellazzini, Brando; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John

    2016-01-01

    The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in AdS space. For both of these models we consider the processes $gg\\to ZZ$ and $gg\\to hh$, which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.

  1. Higgs physics at LHC

    Indian Academy of Sciences (India)

    The large hadron collider (LHC) and its detectors, ATLAS and CMS, are being built to study TeV scale physics, and to fully understand the electroweak symmetry breaking mechanism. The Monte-Carlo simulation results for the standard model and minimal super symmetric standard model Higgs boson searches and ...

  2. Quantum Critical Higgs

    Science.gov (United States)

    Bellazzini, Brando; Csáki, Csaba; Hubisz, Jay; Lee, Seung J.; Serra, Javi; Terning, John

    2016-10-01

    The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However, light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper, we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in anti-de Sitter space. For both of these models, we consider the processes g g →Z Z and g g →h h , which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.

  3. Minimal mirror twin Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, Riccardo [Institute of Theoretical Studies, ETH Zurich,CH-8092 Zurich (Switzerland); Scuola Normale Superiore,Piazza dei Cavalieri 7, 56126 Pisa (Italy); Hall, Lawrence J.; Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States)

    2016-11-29

    In a Mirror Twin World with a maximally symmetric Higgs sector the little hierarchy of the Standard Model can be significantly mitigated, perhaps displacing the cutoff scale above the LHC reach. We show that consistency with observations requires that the Z{sub 2} parity exchanging the Standard Model with its mirror be broken in the Yukawa couplings. A minimal such effective field theory, with this sole Z{sub 2} breaking, can generate the Z{sub 2} breaking in the Higgs sector necessary for the Twin Higgs mechanism. The theory has constrained and correlated signals in Higgs decays, direct Dark Matter Detection and Dark Radiation, all within reach of foreseen experiments, over a region of parameter space where the fine-tuning for the electroweak scale is 10-50%. For dark matter, both mirror neutrons and a variety of self-interacting mirror atoms are considered. Neutrino mass signals and the effects of a possible additional Z{sub 2} breaking from the vacuum expectation values of B−L breaking fields are also discussed.

  4. Improved prediction for the mass of the W boson in the NMSSM

    International Nuclear Information System (INIS)

    Staal, O.; Zeune, L.

    2015-10-01

    Electroweak precision observables, being highly sensitive to loop contributions of new physics, provide a powerful tool to test the theory and to discriminate between different models of the underlying physics. In that context, the W boson mass, M W , plays a crucial role. The accuracy of the M W measurement has been significantly improved over the last years, and further improvement of the experimental accuracy is expected from future LHC measurements. In order to fully exploit the precise experimental determination, an accurate theoretical prediction for M W in the Standard Model (SM) and extensions of it is of central importance. We present the currently most accurate prediction for the W boson mass in the Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM), including the full one-loop result and all available higher-order corrections of SM and SUSY type. The evaluation of M W is performed in a flexible framework, which facilitates the extension to other models beyond the SM. We show numerical results for the W boson mass in the NMSSM, focussing on phenomenologically interesting scenarios, in which the Higgs signal can be interpreted as the lightest or second lightest CP-even Higgs boson of the NMSSM. We find that, for both Higgs signal interpretations, the NMSSM M W prediction is well compatible with the measurement. We study the SUSY contributions to M W in detail and investigate in particular the genuine NMSSM effects from the Higgs and neutralino sectors.

  5. Is radiative electroweak symmetry breaking consistent with a 125 GeV Higgs mass?

    Science.gov (United States)

    Steele, T G; Wang, Zhi-Wei

    2013-04-12

    The mechanism of radiative electroweak symmetry breaking occurs through loop corrections, and unlike conventional symmetry breaking where the Higgs mass is a parameter, the radiatively generated Higgs mass is dynamically predicted. Padé approximations and an averaging method are developed to extend the Higgs mass predictions in radiative electroweak symmetry breaking from five- to nine-loop order in the scalar sector of the standard model, resulting in an upper bound on the Higgs mass of 141 GeV. The mass predictions are well described by a geometric series behavior, converging to an asymptotic Higgs mass of 124 GeV consistent with the recent ATLAS and CMS Collaborations observations. Similarly, we find that the Higgs self-coupling converges to λ=0.23, which is significantly larger than its conventional symmetry breaking counterpart for a 124 GeV Higgs mass. In addition to this significant enhancement of the Higgs self-coupling and HH→HH scattering, we find that Higgs decays to gauge bosons are unaltered and the scattering processes WL(+)WL(+)→HH, ZLZL→HH are also enhanced, providing signals to distinguish conventional and radiative electroweak symmetry breaking mechanisms.

  6. Phenomenology of Baryon Resonances

    Energy Technology Data Exchange (ETDEWEB)

    Doring, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Landay, Justin [George Washington Univ., Washington, DC (United States); Mai, Maxim [George Washington Univ., Washington, DC (United States); Molina, Raquel [Univ. of Sao Paulo (Brazil); Ronchen, Deborah [Univ. of Bonn (Germany)

    2018-04-01

    Results for light baryon spectroscopy by different collaborations and the state of the art in the subfield is reviewed. Highlights contain common efforts of different phenomenology groups and the impact of recent high-precision data from ELSA, JLab, MAMI, and other facilities. Questions will be addressed, on one side, of how to proceed to reach conclusive answers in baryon spectroscopy, and, on the other side, how phenomenology can be connected to theory in a meaningful way.

  7. On the Tuning and the Mass of the Composite Higgs

    CERN Document Server

    Panico, Giuliano; Tesi, Andrea; Wulzer, Andrea

    2013-01-01

    We analyze quantitatively the tuning of composite Higgs models with partial compositeness and its interplay with the predicted Higgs mass. In this respect we identify three classes of models, characterized by different quantum numbers of the fermionic colored resonances associated with the top quark, the so-called top partners. The main result of this classification is that in all models with moderate tuning a light Higgs, of 125 GeV mass, requires the presence of light top partners, around 1 TeV. The minimal tuning is comparable to the one of the most attractive supersymmetric models in particular the ones realizing Natural SUSY. This gives further support to an extensive program of top partners searches at the LHC that can already probe the natural region of composite Higgs models.

  8. Classical and quantum initial conditions for Higgs inflation

    Directory of Open Access Journals (Sweden)

    Alberto Salvio

    2015-11-01

    Full Text Available We investigate whether Higgs inflation can occur in the Standard Model starting from natural initial conditions or not. The Higgs has a non-minimal coupling to the Ricci scalar. We confine our attention to the regime where quantum Einstein gravity effects are small in order to have results that are independent of the ultraviolet completion of gravity. At the classical level we find no tuning is required to have successful Higgs inflation, provided the initial homogeneity condition is satisfied. On the other hand, at the quantum level we obtain that the renormalization for large non-minimal coupling requires an additional degree of freedom, unless a tuning of the initial values of the running parameters is made. In order to see that this effect may change the predictions we finally include such degree of freedom in the field content and show that Starobinsky's R2 inflation dominates over Higgs inflation.

  9. Phenomenological analysis of D-brane Pati-Salam vacua

    CERN Document Server

    Anastasopoulos, P.; Vlachos, N.D.

    2010-01-01

    In the present work we perform a phenomenological analysis of the effective low energy models with Pati-Salam (PS) gauge symmetry derived in the context of D-branes. A main issue in these models arises from the fact that the right-handed fermions and the PS-symmetry breaking Higgs field transform identically under the PS symmetry, causing unnatural matter-Higgs mixing effects. We argue that this problem could be solved in particular D-brane setups where these fields arise in different intersections. We further observe that whenever a large Higgs mass term is generated in a particular class of mass spectra, a splitting mechanism -reminiscent of the doublet triplet splitting- may protect the neutral Higgs components from a heavy mass term. We analyze the implications of each individual representation which in principle is available in these models in order to specify the minimal spectrum required to build up a consistent PS model which reconciles the low energy data. A short discussion is devoted on the effects...

  10. Higgs-boson contributions to gauge-boson mass shifts in extended electroweak models

    International Nuclear Information System (INIS)

    Moore, S.R.

    1985-10-01

    In the minimal standard model, the difference between the tree-level and one-loop-corrected predictions for the gauge-boson masses, known as the mass shifts, are of the order of 4%. The dominant contribution is from light-fermion loops. The Higgs-dependent terms are small, even if the Higgs boson is heavy. We have analyzed the mass shifts for models with a more complicated Higgs sector. We use the on-shell renormalization scheme, in which the parameters of the theory are the physical masses and couplings. We have considered the 2-doublet, n-doublet, triplet and doublet-triplet models. We have found that the Z-boson mass prediction has a strong dependence on the charged-Higgs mass. In the limit that the charged Higgs is much heavier than the gauge bosons, the Higgs-dependent terms become significant, and may even cancel the light-fermion terms. In the models with a Higgs triplet, there is also a strong dependence on the neutral-Higgs masses, although this contribution tends to be suppressed in realistic models. The W-boson mass shift does not have a strong Higgs dependence. If we use the Z mass as input in determining the parameters of the theory, a scenario which will become attractive as the mass of the Z is accurately measured in the next few years, we find that the W-boson mass shift exhibits the same sort of behavior, differing from the minimal model for the case of the charged Higgs being heavy. We have found that when radiative corrections are taken into account, models with extended Higgs sectors may differ significantly from the minimal standard model in their predictions for the gauge-boson masses. Thus, an accurate measurement of the masses will help shed light on the structure of the Higgs sector. 68 refs

  11. Electroweak Higgs production with HiggsPO at NLO QCD

    International Nuclear Information System (INIS)

    Greljo, Admir; Isidori, Gino; Zhang, Hantian; Lindert, Jonas M.; Marzocca, David

    2017-01-01

    We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p T for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available. (orig.)

  12. Electroweak Higgs production with HiggsPO at NLO QCD

    Science.gov (United States)

    Greljo, Admir; Isidori, Gino; Lindert, Jonas M.; Marzocca, David; Zhang, Hantian

    2017-12-01

    We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p_T for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available.

  13. Electroweak Higgs production with HiggsPO at NLO QCD

    Energy Technology Data Exchange (ETDEWEB)

    Greljo, Admir [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Johannes Gutenberg-Universitaet Mainz, PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics, Mainz (Germany); University of Sarajevo, Faculty of Science, Sarajevo (Bosnia and Herzegovina); Isidori, Gino; Zhang, Hantian [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Lindert, Jonas M. [Durham University, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Marzocca, David [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); INFN, Sezione di Trieste(Italy); SISSA, Trieste (Italy)

    2017-12-15

    We present the HiggsPO UFO model for Monte Carlo event generation of electroweak VH and VBF Higgs production processes at NLO in QCD in the formalism of Higgs pseudo-observables (PO). We illustrate the use of this tool by studying the QCD corrections, matched to a parton shower, for several benchmark points in the Higgs PO parameter space. We find that, while being sizable and thus important to be considered in realistic experimental analyses, the QCD higher-order corrections largely factorize. As an additional finding, based on the NLO results, we advocate to consider 2D distributions of the two-jet azimuthal-angle difference and the leading jet p{sub T} for new physics searches in VBF Higgs production. The HiggsPO UFO model is publicly available. (orig.)

  14. Torsion as a dark matter candidate from the Higgs portal

    Science.gov (United States)

    Belyaev, Alexander S.; Thomas, Marc C.; Shapiro, Ilya L.

    2017-05-01

    Torsion is a metric-independent component of gravitation, which may provide a more general geometry than the one taking place within general relativity. On the other hand, torsion could lead to interesting phenomenology in both particle physics and cosmology. In the present work it is shown that a torsion field interacting with the SM Higgs doublet and having a negligible coupling to standard model (SM) fermions is protected from decaying by a Z2 symmetry, and therefore becomes a promising dark matter (DM) candidate. This model provides a good motivation for Higgs portal vector DM scenario. We evaluate the DM relic density and explore direct DM detection and collider constraints on this model to understand its consistency with experimental data and establish the most up-to-date limits on its parameter space. We have found in the model when the Higgs boson is only partly responsible for the generation of torsion mass, there is a region of parameter space where torsion contributes 100% to the DM budget of the Universe. Furthermore, we present the first results on the potential of the LHC to probe the parameter space of minimal scenario with Higgs portal vector DM using mono-jet searches and have found that LHC at high luminosity will be sensitive to the substantial part of model parameter space which cannot be probed by other experiments.

  15. Anomaly mediated supersymmetric models and Higgs data from the LHC

    CERN Document Server

    Arbey, A; Mahmoudi, F; Tarhini, A

    2013-01-01

    Anomaly mediation models are well motivated supersymmetry breaking scenarios which appear as alternatives to the mSUGRA paradigm. These models are quite compelling from the theoretical point of view and it is therefore important to test if they are also viable models for phenomenology. We perform a study of these models in the light of all standard flavour, collider and dark matter constraints, including also the recent Higgs boson measurements for the mass and signal strengths in the different decay channels. The minimal AMSB scenario can satisfy in part of its parameter space the dark matter requirement but is only marginally consistent with the current Higgs boson mass value. The HyperCharge-AMSB and Mixed Moduli-AMSB scenarios can better describe present data from dark matter, flavour, low energy physics and are consistent with the measured mass of the Higgs boson. The inclusion of the preferred signal strengths for the Higgs boson decay channels shows that for tan(beta) > 5 the HC-AMSB and MM-AMSB models...

  16. The Standard Model and Higgs physics

    Science.gov (United States)

    Torassa, Ezio

    2018-05-01

    The Standard Model is a consistent and computable theory that successfully describes the elementary particle interactions. The strong, electromagnetic and weak interactions have been included in the theory exploiting the relation between group symmetries and group generators, in order to smartly introduce the force carriers. The group properties lead to constraints between boson masses and couplings. All the measurements performed at the LEP, Tevatron, LHC and other accelerators proved the consistency of the Standard Model. A key element of the theory is the Higgs field, which together with the spontaneous symmetry breaking, gives mass to the vector bosons and to the fermions. Unlike the case of vector bosons, the theory does not provide prediction for the Higgs boson mass. The LEP experiments, while providing very precise measurements of the Standard Model theory, searched for the evidence of the Higgs boson until the year 2000. The discovery of the top quark in 1994 by the Tevatron experiments and of the Higgs boson in 2012 by the LHC experiments were considered as the completion of the fundamental particles list of the Standard Model theory. Nevertheless the neutrino oscillations, the dark matter and the baryon asymmetry in the Universe evidence that we need a new extended model. In the Standard Model there are also some unattractive theoretical aspects like the divergent loop corrections to the Higgs boson mass and the very small Yukawa couplings needed to describe the neutrino masses. For all these reasons, the hunt of discrepancies between Standard Model and data is still going on with the aim to finally describe the new extended theory.

  17. MSSM interpretations of the LHC discovery. Light or heavy Higgs?

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, P.; Stefaniak, T. [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, O. [Stockholm Univ. (Sweden). The Oskar Klein Centre; Weiglein, G.; Zeune, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-11-15

    A Higgs-like particle with a mass of about 126 GeV has been discovered at the LHC. Within the experimental uncertainties, the measured properties of this new state are compatible with those of the Higgs boson in the Standard Model (SM). While not statistically significant at present, the results show some interesting patterns of deviations from the SM predictions, in particular a higher rate in the {gamma}{gamma} decay mode observed by ATLAS and CMS, and a somewhat smaller rate in the {tau}{sup +}{tau}{sup -} mode. The LHC discovery is also compatible with the predictions of the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM), interpreting the new state as either the light or the heavy CP-even MSSM Higgs boson. Within the framework of the MSSM with seven free parameters (pMSSM-7), we fit the various rates of cross section times branching ratio as measured by the LHC and Tevatron experiments under the hypotheses of either the light or the heavy CP-even Higgs boson being the new state around 126 GeV, with and without the inclusion of further lowenergy observables. We find an overall good quality of the fits, with the best fit points exhibiting an enhancement of the {gamma}{gamma} rate, as well as a small suppression of the b anti b and {tau}{sup +}{tau}{sup -} channels with respect to their SM expectations, depending on the details of the fit. For the fits including the whole data set the light CP-even Higgs interpretation in the MSSM results in a higher relative fit probability than the SM fit. On the other hand, we find that the present data also permit the more exotic interpretation in terms of the heavy CP-even MSSM Higgs, which could give rise to experimental signatures of additional Higgs states in the near future.

  18. SEARCHING FOR HIGGS BOSONS AND NEW PHYSICS AT HADRON COLLIDERS

    International Nuclear Information System (INIS)

    Chung Kao

    2007-01-01

    The objectives of research activities in particle theory are predicting the production cross section and decay branching fractions of Higgs bosons and new particles at hadron colliders, developing techniques and computer software to discover these particles and to measure their properties, and searching for new phenomena and new interactions at the Fermilab Tevatron and the CERN Large Hadron Collider. The results of our project could lead to the discovery of Higgs bosons, new particles, and signatures for new physics, or we will be able to set meaningful limits on important parameters in particle physics. We investigated the prospects for the discovery at the CERN Large Hadron Collider of Higgs bosons and supersymmetric particles. Promising results are found for the CP-odd pseudoscalar (A 0 ) and the heavier CP-even scalar (H 0 ) Higgs bosons with masses up to 800 GeV. Furthermore, we study properties of the lightest neutralino (χ 0 ) and calculate its cosmological relic density in a supersymmetric U(1)(prime) model as well as the muon anomalous magnetic moment a μ = (g μ -2)/2 in a supersymmetric U(1)(prime) model. We found that there are regions of the parameter space that can explain the experimental deviation of a μ from the Standard Model calculation and yield an acceptable cold dark matter relic density without conflict with collider experimental constraints. Recently, we presented a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion (b(bar b) to hh) at the CERN Large Hadron Collider (LHC) in the Standard Model and the minimal supersymmetric model. We plan to predict the Higgs pair production rate and to study the trilinear coupling among the Higgs bosons. In addition, we have made significant contributions in B physics, single top production, charged Higgs search at the Fermilab as well as in grid computing for both D0 and ATLAS

  19. The first lessons of the LHC: the Higgs boson and supersymmetry

    International Nuclear Information System (INIS)

    Kazakov, D.I.

    2013-01-01

    We discuss recent results on the Higgs boson discovery and search for supersymmetry at the LHC. Is the Higgs boson really discovered and if yes is it the Higgs boson of the Standard Model? Which properties of the discovered particle are consistent with the SM and what are the alternatives? Could it be that two Higgs bosons are discovered? What one can say about the stability of the electroweak vacuum if the Higgs boson has a mass of 125 GeV? What are the predictions of SUSY theories concerning the Higgs boson mass? Does the value of 125 GeV support SUSY or contradict it? What is the situation with SUSY searches and what is left of SUSY parameter space? Is low energy SUSY still alive? What are the perspectives of SUSY finding at the LHC at 14 TeV?

  20. NMSSM Higgs boson search in events containing 2b+2τ

    Energy Technology Data Exchange (ETDEWEB)

    Anstruther, Yasmin; Beskidt, Conny; Boer, Wim de; Wayand, Stefan; Wolf, Roger [EKP, KIT, Karlsruhe (Germany)

    2015-07-01

    The discovery of a Higgs boson at the LHC was a great success. However supersymmetric extensions of the Standard Model predict more than one Higgs boson. The NMSSM Higgs sector contains seven Higgs bosons, of which the three lightest are neutral and CP even. This allows for a via gluon-gluon fusion produced heavy H{sub 3} to decay into the SM-like H{sub 2} and an even lighter H{sub 1}. These then decay into two tau leptons and two b quarks, respectively. Private results and exclusion limits of this analysis are presented.

  1. More on Higgs bosons in SU(5)

    International Nuclear Information System (INIS)

    Hueffel, H.

    1980-01-01

    In the framework of the minimal SU(5) model of Georgi and Glashow the explicit couplings between the various mass eigenstate Higgs bosons and the gauge fields as well as the Higgs boson self couplings are presented. As an application bounds for the parameters of the Higgs potential and for the Higgs boson masses are derived by applying partial wave unitarity to the tree graphs of Higgs-Higgs scattering. (Auth.)

  2. Higgs boson, renormalization group, and naturalness in cosmology

    International Nuclear Information System (INIS)

    Barvinsky, A.O.; Kamenshchik, A.Yu.; Kiefer, C.; Starobinsky, A.A.; Steinwachs, C.F.

    2012-01-01

    We consider the renormalization group improvement in the theory of the Standard Model (SM) Higgs boson playing the role of an inflaton with a strong non-minimal coupling to gravity. At the one-loop level with the running of constants taken into account, it leads to a range of the Higgs mass that is entirely determined by the lower WMAP bound on the cosmic microwave background (CMB) spectral index. We find that the SM phenomenology is sensitive to current cosmological data, which suggests to perform more precise CMB measurements as a SM test complementary to the LHC program. By using the concept of a field-dependent cutoff, we show the naturalness of the gradient and curvature expansion in this model within the conventional perturbation theory range of the SM. We also discuss the relation of these results to two-loop calculations and the limitations of the latter caused by parametrization and gauge dependence problems. (orig.)

  3. The Higgs portal above threshold

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Lou, Hou Keong [Department of Physics, Princeton University,Princeton, NJ 08540 (United States); McCullough, Matthew [Theory Division, CERN,1211 Geneva 23 (Switzerland); Thalapillil, Arun [Department of Physics and Astronomy, Rutgers University,Piscataway, NJ 08854 (United States)

    2016-02-18

    The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.

  4. The Higgs portal above threshold

    International Nuclear Information System (INIS)

    Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; Thalapillil, Arun

    2016-01-01

    The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.

  5. Higgs Tasting Workshop 2016: Higgs and flavor in the LHC Run 2 era

    CERN Document Server

    2016-01-01

    The discovery of a Higgs particle by the LHC experiments has launched the exploration of electroweak symmetry breaking and potentially opened a new window into beyond Standard Model physics. Measurements of Higgs boson properties during Run 1 of the LHC are broadly consistent with the Standard Model predictions, although they leave significant room for New Physics contributions. At the same time, a number of exciting anomalies in low-energy precision flavor observables have cumulated over the years, whose potential implications are yet to be fully gauged. One of the most pressing questions in high energy physics is the origin of flavor and it is undeniably linked in an intimate way to the physics of the Higgs boson. The Standard Model comes with definite predictions for the structure of the couplings between the Higgs boson and the fermions. Probing this structure or observing any deviation will have long-reaching implications on our understanding on how Nature works at its most fundamental level, including c...

  6. Maximally Symmetric Composite Higgs Models.

    Science.gov (United States)

    Csáki, Csaba; Ma, Teng; Shu, Jing

    2017-09-29

    Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.

  7. Light Higgs from pole attractor

    International Nuclear Information System (INIS)

    Matsedonskyi, Oleksii; Montull, Marc

    2017-09-01

    We propose a new way of explaining the observed Higgs mass, within the cosmological relaxation framework. The key feature distinguishing it from other scanning scenarios is that the scanning field has a non-canonical kinetic term, whose role is to terminate the scan around the desired Higgs mass value. We propose a concrete realisation of this idea with two new singlet fields, one that scans the Higgs mass, and another that limits the time window in which the scan is possible. Within the provided time period, the scanning field does not significantly evolve after the Higgs field gets close to the Standard Model value, due to particle production friction.

  8. Light Higgs bosons at LEP

    International Nuclear Information System (INIS)

    Ekspong, G.

    1981-11-01

    Among possible production reactions for neutral Higgs bosons it is known that e + e - →Z 0 +H 0 offers advantages of relatively high production cross section and low background from other reactions. With Z 0 decaying to two electrons, which are measured, the existence of a Higgs candidate will be seen as a peak in the missing mass spectrum. It is shown that a sufficiently good mass resolution is obtainable to make a search for Higgs feasible at LEP. In its first phase, the energy of LEP limits the search to Higgs bosons of mass around 10 GeV. (Auth.)

  9. Higgs mass bounds from a chirally invariant lattice Higgs-Yukawa model with overlap fermions

    International Nuclear Information System (INIS)

    Gerhold, Philipp; Kallarackal, Jim

    2008-10-01

    We study the parameter dependence of the Higgs mass in a chirally invariant lattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure as in the Higgs sector of the electroweak Standard Model. Eventually, the aim is to establish upper and lower Higgs mass bounds. Here we present our preliminary results on the lower Higgs mass bound at several selected values for the cutoff and give a brief outlook towards the upper Higgs mass bound. (orig.)

  10. The limit of the Yang-Mills-Higgs flow on Higgs bundles

    OpenAIRE

    Li, Jiayu; Zhang, Xi

    2014-01-01

    In this paper, we consider the gradient flow of the Yang-Mills-Higgs functional for Higgs pairs on a Hermitian vector bundle $(E, H_{0})$ over a compact K\\"ahler manifold $(M, \\omega )$. We study the asymptotic behavior of the Yang-Mills-Higgs flow for Higgs pairs at infinity, and show that the limiting Higgs sheaf is isomorphic to the double dual of the graded Higgs sheaves associated to the Harder-Narasimhan-Seshadri filtration of the initial Higgs bundle.

  11. Integrating over Higgs branches

    International Nuclear Information System (INIS)

    Moore, G.; Shatashvili, S.

    2000-01-01

    We develop some useful techniques for integrating over Higgs branches in supersymmetric theories with 4 and 8 supercharges. In particular, we define a regularized volume for hyperkaehler quotients. We evaluate this volume for certain ALE and ALF spaces in terms of the hyperkaehler periods. We also reduce these volumes for a large class of hyperkaehler quotients to simpler integrals. These quotients include complex coadjoint orbits, instanton moduli spaces on R 4 and ALE manifolds, Hitchin spaces, and moduli spaces of (parabolic) Higgs bundles on Riemann surfaces. In the case of Hitchin spaces the evaluation of the volume reduces to a summation over solutions of Bethe ansatz equations for the non-linear Schroedinger system. We discuss some applications of our results. (orig.)

  12. Searches for BSM Higgs bosons at ATLAS, including rare and invisible decays

    CERN Document Server

    Otero y Garzon, Gustavo; The ATLAS collaboration

    2017-01-01

    Several theories beyond the Standard Model predict the existence of high mass neutral or charged Higgs particles or BSM decay modes of the 125 GeV Higgs boson. In this presentation the latest ATLAS results on searches for these particles will be discussed.

  13. Looking For Physics Beyond The Standard Model: Searches For Charged Higgs Bosons At $e^{+}e^{-}$ Colliders

    CERN Document Server

    Kiiskinen, A P

    2004-01-01

    This thesis describes direct searches for pair production of charged Higgs bosons performed in the data collected by the DELPHI detector at the LEP collider at CERN. In addition, the possibilities to discover and study heavy charged Higgs bosons at possible future high-energy linear colliders are presented. The existence of charged Higgs bosons is predicted by many extensions of the Standard Model. A possible discovery of these particles would be a solid proof for physics beyond the Standard Model. Discovery of charged Higgs bosons, and measurement of their properties, would also provide useful information about the structure of the more general theory. New analysis methods were developed for the searches performed at LEP. A large, previously unexplored, mass range for cover but no evidence for the existence of the charged Higgs bosons was found. This allowed setting new lower mass limits for the charged Higgs boson within the framework of general two Higgs doublet models. Results have been interpreted and pr...

  14. DELPHI: Higgs candidate

    CERN Multimedia

    2001-01-01

    This track is an example of real data collected from the DELPHI detector on the Large Electron-Positron (LEP) collider at CERN, which ran between 1989 and 2000. Its topology is compatible with what is expected from the associated production of a Z boson and Higgs boson of mass 113 GeV that each decay into two jets. A different pairing of the jets could lead to an interpretation compatible with the production of two Z bosons.

  15. Higgs physics: Theory

    Indian Academy of Sciences (India)

    2012-10-06

    Oct 6, 2012 ... confidence level (CL) established at LEP2 [4]. ... particle is not self-consistent at high energies as it leads to ... matter and thus impact their density in the Universe today. ... s = 7 TeV LHC, lead to a K-factor KNLO ∼ 1.8 in the low Higgs mass ...... See Michael Spira, http://people.web.psi.ch/spira/proglist.html.

  16. Higgs-photon resonances

    Energy Technology Data Exchange (ETDEWEB)

    Dobrescu, Bogdan A.; Fox, Patrick J.; Kearney, John [Fermilab, Theoretical Physics Department, Batavia, IL (United States)

    2017-10-15

    We study models that produce a Higgs boson plus photon (h{sup 0}γ) resonance at the LHC. When the resonance is a Z{sup '} boson, decays to h{sup 0}γ occur at one loop. If the Z{sup '} boson couples at tree level to quarks, then the h{sup 0}γ branching fraction is typically of order 10{sup -5} or smaller. Nevertheless, there are models that would allow the observation of Z{sup '} → h{sup 0}γ at √(s) = 13 TeV with a cross section times branching fraction larger than 1 fb for a Z{sup '} mass in the 200-450 GeV range, and larger than 0.1 fb for a mass up to 800 GeV. The one-loop decay of the Z{sup '} into lepton pairs competes with h{sup 0}γ, even if the Z{sup '} couplings to leptons vanish at tree level. We also present a model in which a Z{sup '} boson decays into a Higgs boson and a pair of collimated photons, mimicking an h{sup 0}γ resonance. In this model, the h{sup 0}γ resonance search would be the discovery mode for a Z{sup '} as heavy as 2 TeV. When the resonance is a scalar, although decay to h{sup 0}γ is forbidden by angular momentum conservation, the h{sup 0} plus collimated photons channel is allowed. We comment on prospects of observing an h{sup 0}γ resonance through different Higgs decays, on constraints from related searches, and on models where h{sup 0} is replaced by a nonstandard Higgs boson. (orig.)

  17. Dirichlet Higgs in Extra-Dimension Consistent with Electroweak Data

    International Nuclear Information System (INIS)

    Naoyuki Habay; Kin-ya Odaz; Ryo Takahashi

    2011-01-01

    We propose a simple five-dimensional extension of the Standard Model (SM) without any Higgs potential nor any extra fields. A Higgs doublet lives in the bulk of a flat line segment and its boundary condition is Dirichlet at the ends of the line, which causes the electroweak symmetry breaking without Higgs potential. The vacuum expectation value of the Higgs is induced from the Dirichlet boundary condition which is generally allowed in higher dimensional theories. The lightest physical Higgs has non-flat profile in the extra dimension even though the vacuum expectation value is flat. As a consequence, we predict a maximal top Yukawa deviation (no coupling between top and Higgs) for the brane-localized fermion and a small deviation, a multiplication of 2√2/π ≅ 0.9 to the Yukawa coupling, for the bulk fermion. The latter is consistent with the electroweak precision data within 90% C.L. for 430 GeV ≤ m KK ≤ 500 GeV. (authors)

  18. arXiv Initial Conditions for Critical Higgs Inflation

    CERN Document Server

    Salvio, Alberto

    2018-05-10

    It has been pointed out that a large non-minimal coupling ξ between the Higgs and the Ricci scalar can source higher derivative operators, which may change the predictions of Higgs inflation. A variant, called critical Higgs inflation, employs the near-criticality of the top mass to introduce an inflection point in the potential and lower drastically the value of ξ . We here study whether critical Higgs inflation can occur even if the pre-inflationary initial conditions do not satisfy the slow-roll behavior (retaining translation and rotation symmetries). A positive answer is found: inflation turns out to be an attractor and therefore no fine-tuning of the initial conditions is necessary. A very large initial Higgs time-derivative (as compared to the potential energy density) is compensated by a moderate increase in the initial field value. These conclusions are reached by solving the exact Higgs equation without using the slow-roll approximation. This also allows us to consistently treat the inflection poi...

  19. Aspects of Higgs Physics and New Physics at the LHC

    CERN Document Server

    Gröber, Ramona

    We study Higgs physics and related issues in the Standard Model (SM) and beyond. In the first part, we present theoretical predictions for Higgs pair production in the SM including higher order corrections in Quantum Chromodynamics (QCD) and the uncertainties on the respective cross sections from various sources. The second part covers supersymmetry. In the framework of the minimal supersymmetric extension of the SM, we investigate decays of light top squarks in the kinematic region where a flavour-changing decay into a charm or up quark and a neutralino or a four-body decay occurs. Furthermore, we discuss the Higgs sector in the next-to-minimal supersymmetric extension of the SM with complex parameters. In particular, we calculate the Higgs boson masses at one-loop order. In addition, we present Higgs boson production cross sections and decay widths. The third part introduces Composite Higgs Models as plausible candidates for physics beyond the SM. We calculate the leadingorder cross section for single and d...

  20. Analysis of the phase structure in extended Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Seniuch, M.

    2006-07-07

    We study the generation of the baryon asymmetry in the context of electroweak baryogenesis in two different extensions of the Standard Model. First, we consider an effective theory, in which the Standard Model is augmented by an additional dimension-six Higgs operator. The effects of new physics beyond a cut-off scale are parameterized by this operator. The second model is the two-Higgs-doublet model, whose particle spectrum is extended by two further neutral and two charged heavy Higgs bosons. In both cases we focus on the properties of the electroweak phase transition, especially on its strength and the profile of the nucleating bubbles. After reviewing some general aspects of the electroweak phase transition and baryogenesis we derive the respective thermal effective potentials to one-loop order. We systematically study the parameter spaces, using numerical methods, and compute the strength of the phase transition and the wall thickness as a function of the Higgs masses. We find a strong first order transition for a light Higgs state with a mass up to about 200 GeV. In case of the dimension-six model the cut-off scale has to stay between 500 and 850 GeV, in the two-Higgs-doublet model one needs at least one heavy Higgs mass of 300 GeV. The wall thickness varies for both theories in the range roughly from two to fifteen, in units of the inverse critical temperature. We also estimate the size of the electron and neutron electric dipole moments, since new sources of CP violation give rise to them. In wide ranges of the parameter space we are not in conflict with the experimental bounds. Finally the baryon asymmetry, which is predicted by these models, is related to the Higgs mass and the other appropriate input parameters. In both models the measured baryon asymmetry can be achieved for natural values of the model parameters. (orig.)

  1. Phenomenological constraints on light mixed sneutrino dark matter scenarios

    Directory of Open Access Journals (Sweden)

    Mitsuru Kakizaki

    2015-10-01

    Full Text Available In supersymmetric models with Dirac neutrinos, the lightest sneutrino can be a good thermal dark matter candidate when the soft sneutrino trilinear parameter is large. In this paper, we focus on scenarios where the mass of the mixed sneutrino LSP is of the order of GeV so the sneutrino dark matter is still viable complying with the limits by current and near future direct detection experiments. We investigate phenomenological constraints in the parameter space of the models, as well as the vacuum stability bound. Finally, we show that the allowed regions can be explored by measuring Higgs boson properties at future collider experiments.

  2. Photon pairs: Quantum chromodynamics continuum and the Higgs ...

    Indian Academy of Sciences (India)

    Resummation is needed to obtain reliable predictions in the range of transverse momentum where the cross-section is the largest. Results are compared with data from the Fermilab Tevatron and predictions are made for the large hadron collider. The QCD continuum is shown to have a softer spectrum than the Higgs boson ...

  3. A Phenomenological Model for Prediction Auto-Ignition and Soot Formation of Turbulent Diffusion Combustion in a High Pressure Common Rail Diesel Engine

    Directory of Open Access Journals (Sweden)

    Qinghui Zhou

    2011-06-01

    Full Text Available A new phenomenological model, the TP (Temperature Phase model, is presented to carry out optimization calculations for turbulent diffusion combustion in a high-pressure common rail diesel engine. Temperature is the most important parameter in the TP model, which includes two parts: an auto-ignition and a soot model. In the auto-ignition phase, different reaction mechanisms are built for different zones. For the soot model, different methods are used for different temperatures. The TP model is then implemented in KIVA code instead of original model to carry out optimization. The results of cylinder pressures, the corresponding heat release rates, and soot with variation of injection time, variation of rail pressure and variation of speed among TP model, KIVA standard model and experimental data are analyzed. The results indicate that the TP model can carry out optimization and CFD (computational fluid dynamics and can be a useful tool to study turbulent diffusion combustion.

  4. Search for non-minimal Higgs bosons in Z0 decays with the L3 detector at LEP

    International Nuclear Information System (INIS)

    Sopczak, A.

    1992-01-01

    A general search for neutral and charged Higgs bosons in e + e - collisions at the Z 0 resonance is reported. No assumption that the Higgs sector consists of one doublet as in the Minimal Standard Model (MSM) is made. In the MSM of electroweak interactions, a single Higgs doublet generates the masses for the gauge bosons and for the charged fermions via spontaneous breaking of the gauge symmetry. With only one doublet, Higgs boson production and decay properties depend only on the Higgs boson mass. The LEP experiments have searched for the MSM Higgs boson and exclude it for masses less than about 60 GeV. It is quite possible that the actual scalar sector in nature has more than one doublet of Higgs bosons or has Higgs bosons in other multiplets. This is expected in many theories that go beyond the Standard Model. In Supersymmetric models, at least two Higgs doublets are predicted. A model with two Higgs doublets illustrates some processes that occur in more general models. If the Higgs sector contains more than a single doublet, rates for bremsstrahlung of the lightest Higgs boson from the Z 0 are no longer uniquely predicted and are generally lower than in the MSM. At the same time, with a richer Higgs sector, pairs of Higgs particles can be produced in Z 0 decays. Therefore, if one is to find a non-MSM Higgs boson at LEP, one must search for bremsstrahlung at lower rates than predicted in the MSM and for Higgs boson pair-production. This work is based on the 1990 and 1991 L3 data sample which totals 408,000 hadronic Z 0 decays, collected at center-of-mass energies between 88.2 and 94.3 GeV. No Higgs signal inconsistent with background is observed in any of the decay channels analyzed. From the results of direct searches, model-independent limits on Higgs boson bremsstrahlung and on Higgs boson pair-production from the Z 0 are presented. The bremsstrahlung limits are interpreted in a general two-doublet model

  5. Vector Higgs-portal dark matter and the invisible Higgs

    International Nuclear Information System (INIS)

    Lebedev, Oleg; Lee, Hyun Min; Mambrini, Yann

    2011-11-01

    The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z 2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stueckelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson. (orig.)

  6. Vector Higgs-portal dark matter and the invisible Higgs

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Oleg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Lee, Hyun Min [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Mambrini, Yann [Paris-Sud Univ., 91 - Orsay (France). Lab. de Physique Theorique

    2011-11-15

    The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z{sub 2} parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stueckelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson. (orig.)

  7. Vector Higgs portal dark matter and the invisible Higgs

    International Nuclear Information System (INIS)

    Lebedev, Oleg; Lee, Hyun Min; Mambrini, Yann

    2012-01-01

    The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z 2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak constraints. We illustrate this idea with the Stückelberg and Higgs mechanisms. Vector DM is consistent with the WMAP, XENON100, and LHC constraints, while it can affect significantly the invisible Higgs decay. Due to the enhanced branching ratio for the Higgs decay into the longitudinal components of the vector field, the vector Higgs portal provides an efficient way to hide the Higgs at the LHC. This could be the reason why the latest combined ATLAS/CMS data did not bring evidence for the existence of the Higgs boson.

  8. Finite size scaling and phenomenological renormalization

    International Nuclear Information System (INIS)

    Derrida, B.; Seze, L. de; Vannimenus, J.

    1981-05-01

    The basic equations of the phenomenological renormalization method are recalled. A simple derivation using finite-size scaling is presented. The convergence of the method is studied analytically for the Ising model. Using this method we give predictions for the 2d bond percolation. Finally we discuss how the method can be applied to random systems

  9. Creativity in phenomenological methodology

    DEFF Research Database (Denmark)

    Dreyer, Pia; Martinsen, Bente; Norlyk, Annelise

    2014-01-01

    on the methodologies of van Manen, Dahlberg, Lindseth & Norberg, the aim of this paper is to argue that the increased focus on creativity and arts in research methodology is valuable to gain a deeper insight into lived experiences. We illustrate this point through examples from empirical nursing studies, and discuss......Nursing research is often concerned with lived experiences in human life using phenomenological and hermeneutic approaches. These empirical studies may use different creative expressions and art-forms to describe and enhance an embodied and personalised understanding of lived experiences. Drawing...... may support a respectful renewal of phenomenological research traditions in nursing research....

  10. Stress tensor for GYM in 4p dimensions and viability of GYM-Higgs in four dimensions

    International Nuclear Information System (INIS)

    O'Brien, G.M.; Tchrakian, D.H.

    1985-01-01

    We present the stress tensor for GYM systems in 4p dimensions and give a method to compute this tensor density for a GYM-Higgs system in four dimensions. This computation is made explicitly for the first such system and its viability in four Euclidean dimensions is checked. The possibility of extracting phenomenological models from this system is analysed briefly. (Author)

  11. Radiative PQ breaking and the Higgs boson mass

    Energy Technology Data Exchange (ETDEWEB)

    D’Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio [Berkeley Center for Theoretical Physics, Department of Physics, and Theoretical Physics Group, Lawrence Berkeley National Laboratory, University of California,Berkeley, CA 94720 (United States)

    2015-06-17

    The small and negative value of the Standard Model Higgs quartic coupling at high scales can be understood in terms of anthropic selection on a landscape where large and negative values are favored: most universes have a very short-lived electroweak vacuum and typical observers are in universes close to the corresponding metastability boundary. We provide a simple example of such a landscape with a Peccei-Quinn symmetry breaking scale generated through dimensional transmutation and supersymmetry softly broken at an intermediate scale. Large and negative contributions to the Higgs quartic are typically generated on integrating out the saxion field. Cancellations among these contributions are forced by the anthropic requirement of a sufficiently long-lived electroweak vacuum, determining the multiverse distribution for the Higgs quartic in a similar way to that of the cosmological constant. This leads to a statistical prediction of the Higgs boson mass that, for a wide range of parameters, yields the observed value within the 1σ statistical uncertainty of ∼5 GeV originating from the multiverse distribution. The strong CP problem is solved and single-component axion dark matter is predicted, with an abundance that can be understood from environmental selection. A more general setting for the Higgs mass prediction is discussed.

  12. Radiative PQ breaking and the Higgs boson mass

    Science.gov (United States)

    D'Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2015-06-01

    The small and negative value of the Standard Model Higgs quartic coupling at high scales can be understood in terms of anthropic selection on a landscape where large and negative values are favored: most universes have a very short-lived electroweak vacuum and typical observers are in universes close to the corresponding metastability boundary. We provide a simple example of such a landscape with a Peccei-Quinn symmetry breaking scale generated through dimensional transmutation and supersymmetry softly broken at an intermediate scale. Large and negative contributions to the Higgs quartic are typically generated on integrating out the saxion field. Cancellations among these contributions are forced by the anthropic requirement of a sufficiently long-lived electroweak vacuum, determining the multiverse distribution for the Higgs quartic in a similar way to that of the cosmological constant. This leads to a statistical prediction of the Higgs boson mass that, for a wide range of parameters, yields the observed value within the 1σ statistical uncertainty of ˜ 5 GeV originating from the multiverse distribution. The strong CP problem is solved and single-component axion dark matter is predicted, with an abundance that can be understood from environmental selection. A more general setting for the Higgs mass prediction is discussed.

  13. Radiative PQ breaking and the Higgs boson mass

    International Nuclear Information System (INIS)

    D’Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2015-01-01

    The small and negative value of the Standard Model Higgs quartic coupling at high scales can be understood in terms of anthropic selection on a landscape where large and negative values are favored: most universes have a very short-lived electroweak vacuum and typical observers are in universes close to the corresponding metastability boundary. We provide a simple example of such a landscape with a Peccei-Quinn symmetry breaking scale generated through dimensional transmutation and supersymmetry softly broken at an intermediate scale. Large and negative contributions to the Higgs quartic are typically generated on integrating out the saxion field. Cancellations among these contributions are forced by the anthropic requirement of a sufficiently long-lived electroweak vacuum, determining the multiverse distribution for the Higgs quartic in a similar way to that of the cosmological constant. This leads to a statistical prediction of the Higgs boson mass that, for a wide range of parameters, yields the observed value within the 1σ statistical uncertainty of ∼5 GeV originating from the multiverse distribution. The strong CP problem is solved and single-component axion dark matter is predicted, with an abundance that can be understood from environmental selection. A more general setting for the Higgs mass prediction is discussed.

  14. The flavor of the composite pseudo-goldstone Higgs

    International Nuclear Information System (INIS)

    Csaki, Csaba; Weiler, Andreas; Falkowski, Adam

    2008-01-01

    We study the flavor structure of 5D warped models that provide a dual description of a composite pseudo-Goldstone Higgs. We first carefully re-examine the flavor constraints on the mass scale of new physics in the standard Randall-Sundrum-type scenarios, and find that the KK gluon mass should generically be heavier than about 21 TeV. We then compare the flavor structure of the composite Higgs models to those in the RS model. We find new contributions to flavor violation, which while still are suppressed by the RS-GIM mechanism, will enhance the amplitudes of flavor violations. In particular, there is a kinetic mixing term among the SM fields which (although parametrically not enhanced) will make the flavor bounds even more stringent than in RS. This together with the fact that in the pseudo-Goldstone scenario Yukawa couplings are set by a gauge coupling implies the KK gluon mass to be at least about 33 TeV. For both the RS and the composite Higgs models the flavor bounds could be stronger or weaker depending on the assumption on the value of the gluon boundary kinetic term. These strong bounds seem to imply that the fully anarchic approach to flavor in warped extra dimensions is implausible, and there have to be at least some partial flavor symmetries appearing that eliminate part of the sources for flavor violation. We also present complete expressions for the radiatively generated Higgs potential of various 5D implementations of the composite Higgs model, and comment on the 1-5 percent level tuning needed in the top sector to achieve a phenomenologically acceptable vacuum state.

  15. Supersymmetry and supergravity: Phenomenology and grand unification

    International Nuclear Information System (INIS)

    Arnowitt, R.; Nath, P.

    1993-01-01

    A survey is given of supersymmetry and supergravity and their phenomenology. Some of the topics discussed are the basic ideas of global supersymmetry, the minimal supersymmetric Standard Model (MSSM) and its phenomenology, the basic ideas of local supersymmetry (supergravity), grand unification, supersymmetry breaking in supergravity grand unified models, radiative breaking of SU(2) x U(1), proton decay, cosmological constraints, and predictions of supergravity grand unified models. While the number of detailed derivations are necessarily limited, a sufficient number of results are given so that a reader can get a working knowledge of this field

  16. Learning from Higgs physics at future Higgs factories

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Jiayin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chinese Academy of Sciences, Beijing (China). Center for Future High Energy Physics; Li, Honglei [Jinan Univ., Shandong (China). School of Physics and Technology; Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Liu, Zhen [Fermi National Accelerator Laboratory, Batavia, IL (United States). Theoretical Physics Dept.; Su, Shufang [Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Su, Wei [Arizona Univ., Tucson, AZ (United States). Dept. of Physics; Chinese Academy of Sciences, Beijing (China). Inst. of Theoretical Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physics

    2017-09-15

    Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explored its sensitivity to new physics models at the electron-positron colliders. In particular, we studied two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We performed a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtained the limits on the singlet-doublet mixing angle sinθ, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyzed tree level effects in tanβ vs. cos(β-α) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtained lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compared the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).

  17. Learning from Higgs physics at future Higgs factories

    International Nuclear Information System (INIS)

    Gu, Jiayin; Chinese Academy of Sciences, Beijing; Li, Honglei; Arizona Univ., Tucson, AZ; Liu, Zhen; Su, Shufang; Su, Wei; Chinese Academy of Sciences, Beijing; Univ. of Chinese Academy of Sciences, Beijing

    2017-09-01

    Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explored its sensitivity to new physics models at the electron-positron colliders. In particular, we studied two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We performed a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtained the limits on the singlet-doublet mixing angle sinθ, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyzed tree level effects in tanβ vs. cos(β-α) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtained lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compared the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).

  18. Grand unified supersymmetric Higgs bosons as pseudo-Goldstone particles

    International Nuclear Information System (INIS)

    Barbieri, R.; Dvali, G.; Strumia, A.

    1993-01-01

    We reconsider the possibility that the Higgs doublet responsible for the breaking of the electroweak gauge group be quasi-Goldstone bosons of a spontaneously broken approximate global symmetry of the theory. Supersymmetric SU(5) and SO(10) gauge models are discussed. The main phenomenological consequence of this viewpoint is the possible existence at the Fermi scale of a quasi-stable particle, most likely a Lorentz scalar, with the same colour and charge as a down quark. Its existence is a generic feature of models based on SO(10). The associated phenomoenological is illustrated. We also show how the phenomenology of the minimal SU(5) theory, already proposed, gets tightly constrained by the consideration of coupling constant unification without any assumption, otherwise crucial, on the superheavy threshold effects. (orig.)

  19. Tadpole-induced electroweak symmetry breaking and pNGB Higgs models

    Energy Technology Data Exchange (ETDEWEB)

    Harnik, Roni; Howe, Kiel; Kearney, John [Theoretical Physics Department, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2017-03-22

    We investigate induced electroweak symmetry breaking (EWSB) in models in which the Higgs is a pseudo-Nambu-Goldstone boson (pNGB). In pNGB Higgs models, Higgs properties and precision electroweak measurements imply a hierarchy between the EWSB and global symmetry-breaking scales, v{sub H}≪f{sub H}. When the pNGB potential is generated radiatively, this hierarchy requires fine-tuning to a degree of at least ∼v{sub H}{sup 2}/f{sub H}{sup 2}. We show that if Higgs EWSB is induced by a tadpole arising from an auxiliary sector at scale f{sub Σ}≪v{sub H}, this tuning is significantly ameliorated or can even be removed. We present explicit examples both in Composite Higgs models based on SO(5)/SO(4) and in Twin Higgs models. For the Twin case, the result is a fully natural model with f{sub H}∼1 TeV and the lightest colored top partners at 2 TeV. These models also have an appealing mechanism to generate the scales of the auxiliary sector and Higgs EWSB directly from the scale f{sub H}, with a natural hierarchy f{sub Σ}≪v{sub H}≪f{sub H}∼TeV. The framework predicts modified Higgs coupling as well as new Higgs and vector states at LHC13.

  20. Fundamental Composite (Goldstone) Higgs Dynamics

    DEFF Research Database (Denmark)

    Cacciapaglia, G.; Sannino, Francesco

    2014-01-01

    We provide a unified description, both at the effective and fundamental Lagrangian level, of models of composite Higgs dynamics where the Higgs itself can emerge, depending on the way the electroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a massive excitation of the conden...... searches of new physics at the Large Hadron Collider....

  1. Origins of inert Higgs doublets

    Directory of Open Access Journals (Sweden)

    Thomas W. Kephart

    2016-05-01

    Full Text Available We consider beyond the standard model embedding of inert Higgs doublet fields. We argue that inert Higgs doublets can arise naturally in grand unified theories where the necessary associated Z2 symmetry can occur automatically. Several examples are discussed.

  2. Higgs particle searches at LEP

    International Nuclear Information System (INIS)

    Martin, J.P.

    1996-01-01

    Results on searches for the Higgs particle performed by the four LEP experiments are received in the framework of the Standard Model, Two Doublet Model, and Minimal Supersymmetric Model. The combined mass lower limit for the standard Higgs boson is 66 GeV/c 2 at 95 % CL for a statistics of 14.6 Million hadronic Z decays. (authors)

  3. Higgs physics at the LHC

    CERN Document Server

    Mariotti, Chiara

    2017-01-01

    The first measurements of the mass, the width, and the couplings of the newly discovered Higgs boson at LHC at 7 and 8 TeV center of mass energy will be reviewed. Recent results at 13 TeV center of mass energy will be presented. Finally, searches for additional Higgs bosons in models beyond the standard model will be summarised.

  4. Higgs boson search at ATLAS

    International Nuclear Information System (INIS)

    Hanninger, Guilherme Nunes

    2012-01-01

    Full text: The Standard Model of particle physics (SM) has been extremely successful describing the elementary particles and their interactions. It also features a theory describing the origin of particle masses: the 'Higgs mechanism', which postulates the existence of a new particle called the 'Higgs boson'. In 2011 and 2012, tantalising hints of the Higgs boson were reported by the experiments at the Large Hadron Collider (LHC). The results of the search for the Standard Model Higgs Boson with the ATLAS detector in proton-proton collisions at the LHC at 7 and 8 TeV center-of-mass energies are presented. A large number of the Higgs Boson decay channels, such as photon, tau, W and Z pairs, as well as for combined channels in the mass range from 110 GeV to 600 GeV are reviewed and discussed. The combined upper limits on the production cross section as a function of the Higgs Boson mass are derived. Practical methods to estimate the backgrounds using control samples in real data are discussed. Validation of some of the data driven background estimation methods using the early 7 TeV ATLAS data at the LHC is also presented. In addition, searches for Higgs Bosons in scenarios beyond the Standard Model (BSM) lead to improved constraints on the Higgs sector of BSM theories such as Supersymmetry. (author)

  5. Standard model without Higgs particles

    International Nuclear Information System (INIS)

    Kovalenko, S.G.

    1992-10-01

    A modification of the standard model of electroweak interactions with the nonlocal Higgs sector is proposed. Proper form of nonlocality makes Higgs particles unobservable after the electroweak symmetry breaking. They appear only as a virtual state because their propagator is an entire function. We discuss some specific consequences of this approach comparing it with the conventional standard model. (author). 12 refs

  6. Limits on light Higgs bosons

    International Nuclear Information System (INIS)

    Dawson, S.

    1988-01-01

    Experimental limits on light Higgs bosons (M/sub H/ < 5 GeV) are examined. Particular attention is paid to the process K → πH. It is shown that there may be an allowed window for light Higgs bosons between about 100 and 210 MeV. 13 refs., 2 figs

  7. Sasakian and Parabolic Higgs Bundles

    Science.gov (United States)

    Biswas, Indranil; Mj, Mahan

    2018-03-01

    Let M be a quasi-regular compact connected Sasakian manifold, and let N = M/ S 1 be the base projective variety. We establish an equivalence between the class of Sasakian G-Higgs bundles over M and the class of parabolic (or equivalently, ramified) G-Higgs bundles over the base N.

  8. Higgs, supersymmetry and dark matter after Run I of the LHC

    CERN Document Server

    Dumont, Beranger

    2017-01-01

    Two major problems call for an extension of the Standard Model (SM): the hierarchy problem in the Higgs sector and the dark matter in the Universe. The discovery of a Higgs boson with mass of about 125 GeV was clearly the most significant piece of news from CERN's Large Hadron Collider (LHC). In addition to representing the ultimate triumph of the SM, it shed new light on the hierarchy problem and opened up new ways of probing new physics. The various measurements performed at Run I of the LHC constrain the Higgs couplings to SM particles as well as invisible and undetected decays. In this thesis, the impact of the LHC Higgs results on various new physics scenarios is assessed, carefully taking into account uncertainties and correlations between them. Generic modifications of the Higgs coupling strengths, possibly arising from extended Higgs sectors or higher-dimensional operators, are considered. Furthermore, specific new physics models are tested. This includes, in particular, the phenomenological Minimal S...

  9. Quantum Gravity Phenomenology

    OpenAIRE

    Amelino-Camelia, Giovanni

    2003-01-01

    Comment: 9 pages, LaTex. These notes were prepared while working on an invited contribution to the November 2003 issue of Physics World, which focused on quantum gravity. They intend to give a non-technical introduction (accessible to readers from outside quantum gravity) to "Quantum Gravity Phenomenology"

  10. Supersymmetry and Superstring Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, Mary K; Gaillard, Mary K.; Zumino, Bruno

    2008-05-05

    We briefly cover the early history of supersymmetry, describe the relation of SUSY quantum field theories to superstring theories and explain why they are considered a likely tool to describe the phenomenology of high energy particle theory beyond the Standard Model.

  11. The Phenomenology of Democracy

    Science.gov (United States)

    Shaw, Robert

    2009-01-01

    Human beings originate votes, and democracy constitutes decisions. This is the essence of democracy. A phenomenological analysis of the vote and of the decision reveals for us the inherent strength of democracy and its deficiencies. Alexis de Tocqueville pioneered this form of enquiry into democracy and produced positive results from it.…

  12. Superstring inspired phenomenology

    International Nuclear Information System (INIS)

    Binetruy, P.

    1988-01-01

    Recent progress in superstring model building is reviewed with an emphasis on the general features of the models obtained. The problems associated with supersymmetry breaking and intermediate gauge symmetry breaking (M W I GUT ) are described. Finally, the phenomenology of these models is summarized, with a discussion of the role that new experimental results could play to help clearing up the above difficulties

  13. Transversity: Theory and phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    D' Alesio, Umberto [Dipartimento di Fisica, Universita di Cagliari, Cittadella Universitaria, and Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari, C. P. 170, I-09042 Monserrato (Italy)

    2013-04-15

    The distribution of transversely polarized quarks inside a transversely polarized nucleon, known as transversity, encodes a basic piece of information on the nucleon structure, sharing the same status with the more familiar unpolarized and helicity distributions. I will review its properties and discuss different ways to access it, with highlights and limitations. Recent phenomenological extractions and perspectives are also presented.

  14. Transversity: Theory and phenomenology

    International Nuclear Information System (INIS)

    D'Alesio, Umberto

    2013-01-01

    The distribution of transversely polarized quarks inside a transversely polarized nucleon, known as transversity, encodes a basic piece of information on the nucleon structure, sharing the same status with the more familiar unpolarized and helicity distributions. I will review its properties and discuss different ways to access it, with highlights and limitations. Recent phenomenological extractions and perspectives are also presented.

  15. Brane vector phenomenology

    International Nuclear Information System (INIS)

    Clark, T.E.; Love, S.T.; Nitta, Muneto; Veldhuis, T. ter; Xiong, C.

    2009-01-01

    Local oscillations of the brane world are manifested as massive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher-dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints

  16. Inert two-Higgs-doublet model strongly coupled to a non-Abelian vector resonance

    Science.gov (United States)

    Rojas-Abatte, Felipe; Mora, Maria Luisa; Urbina, Jose; Zerwekh, Alfonso R.

    2017-11-01

    We study the possibility of a dark matter candidate having its origin in an extended Higgs sector which, at least partially, is related to a new strongly interacting sector. More concretely, we consider an i2HDM (i.e., a Type-I two Higgs doublet model supplemented with a Z2 under which the nonstandard scalar doublet is odd) based on the gauge group S U (2 )1×S U (2 )2×U (1 )Y . We assume that one of the scalar doublets and the standard fermion transform nontrivially under S U (2 )1 while the second doublet transforms under S U (2 )2. Our main hypothesis is that standard sector is weakly coupled while the gauge interactions associated to the second group is characterized by a large coupling constant. We explore the consequences of this construction for the phenomenology of the dark matter candidate and we show that the presence of the new vector resonance reduces the relic density saturation region, compared to the usual i2DHM, in the high dark matter mass range. In the collider side, we argue that the mono-Z production is the channel which offers the best chances to manifest the presence of the new vector field. We study the departures from the usual i2HDM predictions and show that the discovery of the heavy vector at the LHC is challenging even in the mono-Z channel since the typical cross sections are of the order of 10-2 fb .

  17. The Higgs mass derived from the U(3) Lie group

    DEFF Research Database (Denmark)

    Trinhammer, Ole; Bohr, Henrik; Jensen, Mogens O Stibius

    2015-01-01

    The Higgs mass value is derived from a Hamiltonian on the Lie group U(3) where we relate strong and electroweak energy scales. The baryon states of nucleon and delta resonances originate in specific Bloch wave degrees of freedom coupled to a Higgs mechanism which also gives rise to the usual gauge...... boson masses. The derived Higgs mass is around 125 GeV. From the same Hamiltonian, we derive the relative neutron to proton mass ratio and the N and Delta mass spectra. All compare rather well with the experimental values. We predict scarce neutral flavor baryon singlets that should be visible...... in scattering cross-sections for negative pions on protons, in photoproduction on neutrons, in neutron diffraction dissociation experiments and in invariant mass spectra of protons and negative pions in B-decays. The fundamental predictions are based on just one length scale and the fine structure constant...

  18. Combined Measurements of the Higgs Boson Mass and Couplings

    CERN Document Server

    Zhang, Yu; The ATLAS collaboration

    2017-01-01

    Combined measurements of the Higgs boson mass, as well its production cross sections and branching fractions, are performed using the H->yy and H->ZZ->4l decay channels. The measurements are based on 36.1 fb−1 of proton-proton collision data recorded by the ATLAS experiment at the LHC at sqrt(s)= 13 TeV. The Higgs boson mass is measured to be 124.98 +/- 0.19 (stat) +/- 0.21 (syst) GeV. The rates for gluon fusion, vector-boson fusion, VH, and ttH production, as well as kinematic subdivisions of these processes, are found to be compatible with the Standard Model. The measured ratios of the Higgs boson couplings to their SM predictions are also consistent with the predictions.

  19. Double elementary Goldstone Higgs boson production in future linear colliders

    Science.gov (United States)

    Guo, Yu-Chen; Yue, Chong-Xing; Liu, Zhi-Cheng

    2018-03-01

    The Elementary Goldstone Higgs (EGH) model is a perturbative extension of the Standard Model (SM), which identifies the EGH boson as the observed Higgs boson. In this paper, we study pair production of the EGH boson in future linear electron positron colliders. The cross-sections in the TeV region can be changed to about ‑27%, 163% and ‑34% for the e+e‑→ Zhh, e+e‑→ νν¯hh and e+e‑→ tt¯hh processes with respect to the SM predictions, respectively. According to the expected measurement precisions, such correction effects might be observed in future linear colliders. In addition, we compare the cross-sections of double SM-like Higgs boson production with the predictions in other new physics models.

  20. Future prospects of Higgs Physics at CMS

    OpenAIRE

    Marono, Miguel Vidal

    2014-01-01

    The Higgs boson physics reach of the CMS detector with 300(0) fb-1 of proton-proton collisions at sqrt{s} = 14 TeV is presented. Precision measurements of the Higgs boson properties, Higgs boson pair production and self-coupling, rare Higgs boson decays, and the potential for additional Higgs bosons are discussed. The Higgs boson physics reach of the CMS detector with 300(0) fb-1 of proton-proton collisions at sqrt{s} = 14 TeV is presented. Precision measurements of the Higgs boson propert...

  1. The minimal curvaton-Higgs model

    Energy Technology Data Exchange (ETDEWEB)

    Enqvist, Kari [Helsinki Univ. and Helsinki Institute of Physics (Finland). Physics Dept.; Lerner, Rose N. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Helsinki Univ. and Helsinki Institute of Physics (Finland). Physics Dept.; Takahashi, Tomo [Saga Univ. (Japan). Dept. of Physics

    2013-10-15

    We present the first full study of the minimal curvaton-Higgs (MCH) model, which is a minimal interpretation of the curvaton scenario with one real scalar coupled to the standard model Higgs boson. The standard model coupling allows the dynamics of the model to be determined in detail, including effects from the thermal background and from radiative corrections to the potential. The relevant mechanisms for curvaton decay are incomplete non-perturbative decay (delayed by thermal blocking), followed by decay via a dimension-5 non-renormalisable operator. To avoid spoiling the predictions of big bang nucleosynthesis, we find the ''bare'' curvaton mass to be m{sub {sigma}}{>=}8 x 10{sup 4} GeV. To match observational data from Planck there is an upper limit on the curvaton-higgs coupling g, between 10{sup -3} and 10{sup -2}, depending on the mass. This is due to interactions with the thermal background. We find that typically non-Gaussianities are small but that if f{sub NL} is observed in the near future then m{sub {sigma}}

  2. Does the `Higgs' have Spin Zero?

    CERN Document Server

    Ellis, John

    2012-01-01

    The Higgs boson is predicted to have spin zero. The ATLAS and CMS experiments have recently reported of an excess of events with mass ~ 125 GeV that has some of the characteristics expected for a Higgs boson. We address the questions whether there is already any evidence that this excess has spin zero, and how this possibility could be confirmed in the near future. The excess observed in the gamma gamma final state could not have spin one, leaving zero and two as open possibilities. We calculate the angular distribution of gamma gamma pairs from the decays of a spin-two boson produced in gluon-gluon collisions, showing that is unique and distinct from the spin-zero case. We also calculate the distributions for lepton pairs that would be produced in the W W* decays of a spin-two boson, which are very different from those in Higgs decays, and note that the kinematics of the event selection used to produce the excess observed in the W W* final state have reduced efficiency for spin two.

  3. The minimal curvaton-Higgs model

    International Nuclear Information System (INIS)

    Enqvist, Kari; Lerner, Rose N.; Helsinki Univ. and Helsinki Institute of Physics; Takahashi, Tomo

    2013-10-01

    We present the first full study of the minimal curvaton-Higgs (MCH) model, which is a minimal interpretation of the curvaton scenario with one real scalar coupled to the standard model Higgs boson. The standard model coupling allows the dynamics of the model to be determined in detail, including effects from the thermal background and from radiative corrections to the potential. The relevant mechanisms for curvaton decay are incomplete non-perturbative decay (delayed by thermal blocking), followed by decay via a dimension-5 non-renormalisable operator. To avoid spoiling the predictions of big bang nucleosynthesis, we find the ''bare'' curvaton mass to be m σ ≥8 x 10 4 GeV. To match observational data from Planck there is an upper limit on the curvaton-higgs coupling g, between 10 -3 and 10 -2 , depending on the mass. This is due to interactions with the thermal background. We find that typically non-Gaussianities are small but that if f NL is observed in the near future then m σ 9 GeV, depending on Hubble scale during inflation. In a thermal dark matter model, the lower bound on m σ can increase substantially. The parameter space may also be affected once the baryogenesis mechanism is specified.

  4. Higgs mass in the gauge-Higgs unification

    International Nuclear Information System (INIS)

    Haba, Naoyuki; Takenaga, Kazunori; Yamashita, Toshifumi

    2005-01-01

    The gauge-Higgs unification theory identifies the zero mode of the extra-dimensional component of the gauge field as the usual Higgs doublet. Since this degree of freedom is the Wilson line phase, the Higgs does not have the mass term nor quartic coupling at the tree level. Through quantum corrections, the Higgs can take a vacuum expectation value, and its mass is induced. The radiatively induced mass tends to be small, although it can be lifted to O(100) GeV by introducing the O(10) numbers of bulk fields. Perturbation theory becomes unreliable when a large number of bulk fields are introduced. We reanalyze the Higgs mass based on useful expansion formulae for the effective potential and find that even a small number of bulk field can have the suitable heavy Higgs mass. We show that a small (large) number of bulk fields are enough (needed) when the SUSY breaking mass is large (small). We also study the case of introducing the soft SUSY breaking scalar masses in addition to the Scherk-Schwarz SUSY breaking and obtain the heavy Higgs mass due to the effect of the scalar mass

  5. Phenomenology of CP violation

    International Nuclear Information System (INIS)

    Ecker, G.

    1987-01-01

    A short survey of the theoretical status of CP violation is presented. The Standart Model is confronted with the present experimental situation. Possible future tests of our notions of CP violation are discussed, concentrating on rare K decays. Other promising reactions such as B decays are briefly reviewed. Among alternative models of CP violation, multi-Higgs extensions of the Standart Model, left-right symmetric gauge theories and minimal SUSY models are discussed. Finally, the relevance of generalized CP invariance is emphasized. 64 refs., 7 figs. (Author)

  6. Searches for standard model Higgs boson and supersymmetry - Trigger studies and software tools development for new phenomena in the DO experiment

    International Nuclear Information System (INIS)

    Duperrin, A.

    2007-04-01

    This document presents a summary of my research work during the past 7 years for the preparation of the D0 experiment at Fermilab and the analysis of the data collected at the Tevatron hadron collider. It mainly focuses on 2 topics: trigger and direct search for new phenomena, particularly on supersymmetry and standard model Higgs boson searches. This document is divided into 5 chapters: 1) the phenomenology of the standard model and beyond, 2) the phenomenology of pp-bar events, 3) the Tevatron and D0 detector, 4) the trigger system and data acquisition, and 5) data analysis: search for supersymmetry and Higgs boson

  7. submitter LEP Higgs

    CERN Document Server

    Mori, T

    2001-01-01

    As the LEP experiments verified the gauge interactions more and more rigorously, searches for the Higgs boson, which forms the very basis of the gauge theories, were taking on more and more importance in LEP physics. How this last missing particle in the Standard Model may be discovered (or totally excluded) will be the key to new physics beyond the Standard Model. Here I briefly describe how the LEP experiments together have closed in on this God particle during their 11 year running.

  8. Heavy Higgs boson with a light sneutrino next-to-lightest supersymmetric particle in the MSSM with enhanced SU(2) D-terms

    International Nuclear Information System (INIS)

    Medina, Anibal D.; Shah, Nausheen R.; Wagner, Carlos E. M.

    2009-01-01

    The minimal supersymmetric extension of the standard model provides a solution to the hierarchy problem and leads to the presence of a light Higgs. A Higgs boson with mass above the present experimental bound may only be obtained for relatively heavy third generation squarks, requiring a precise, somewhat unnatural balance between different contributions to the effective Higgs mass parameter. It was recently noticed that somewhat heavier Higgs bosons, which are naturally beyond the CERN LEP bound, may be obtained by enhanced weak SU(2) D-terms. Such contributions appear in models with an enhanced electroweak gauge symmetry, provided the supersymmetry breaking masses associated with the scalars responsible for the breakdown of the enhanced gauge symmetry group to the standard model one are larger than the enhanced symmetry breaking scale. In this article we emphasize that the enhanced SU(2) D-terms will not only raise the Higgs boson mass but also affect the spectrum of the nonstandard Higgs bosons, sleptons, and squarks, which therefore provide a natural contribution to the T parameter, compensating for the negative one coming from the heavy Higgs boson. The sleptons and nonstandard Higgs bosons of these models, in particular, may act in a way similar to the so-called inert Higgs doublet. The phenomenological properties of these models are emphasized, and possible cosmological implications as well as collider signatures are described.

  9. Is the Higgs boson associated with Coleman-Weinberg dynamical symmetry breaking?

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Christopher T. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2014-04-01

    The Higgs mechanism may be a quantum phenomenon, i.e., a Coleman-Weinberg potential generated by the explicit breaking of scale symmetry in Feynman loops. We review the relationship of scale symmetry, trace anomalies, and emphasize the role of the renormalization group in determining Coleman- Weinberg potentials. We propose a simple phenomenological model with "maximal visibility" at the LHC containing a "dormant" Higgs doublet (no VEV, coupled to standard model gauge interactions $SU(2)\\times U(1)$) with a mass of $\\sim 380$ GeV. We discuss the LHC phenomenology and UV challenges of such a model. We also give a schematic model in which new heavy fermions, with masses $\\sim 230$ GeV, can drive a Coleman-Weinberg potential at two-loops. The role of the "improved stress tensor" is emphasized, and we propose a non-gravitational term, analogous to the $\\theta$-term in QCD, which generates it from a scalar action.

  10. Higgs and confinement phases in the fundamental SU(2) Higgs model: Mean field analysis

    International Nuclear Information System (INIS)

    Damgaard, P.H.; Heller, U.M.

    1985-01-01

    The phase diagram of the four-dimensional SU(2) gauge-Higgs model with Higgs field in the fundamental representation is derived by mean field techniques. When the Higgs field is allowed to fluctuate in. Magnitude, the analytic connection between Higgs and confinement phases breaks down for sufficiently small values of the quark Higgs coupling, indicating that the Higgs and confinement phases for these couplings are strictly distinct phases. (orig.)

  11. Higgs quartic coupling and neutrino sector evolution in 2UED models

    KAUST Repository

    Abdalgabar, A.

    2014-05-20

    Two compact universal extra-dimensional models are an interesting class of models for different theoretical and phenomenological issues, such as the justification of having three standard model fermion families, suppression of proton decay rate, dark matter parity from relics of the six-dimensional Lorentz symmetry, origin of masses and mixings in the standard model. However, these theories are merely effective ones, with typically a reduced range of validity in their energy scale. We explore two limiting cases of the three standard model generations all propagating in the bulk or all localised to a brane, from the point of view of renormalisation group equation evolutions for the Higgs sector and for the neutrino sector of these models. The recent experimental results of the Higgs boson from the LHC allow, in some scenarios, stronger constraints on the cutoff scale to be placed, from the requirement of the stability of the Higgs potential. 2014 The Author(s).

  12. Constraining composite Higgs models using LHC data

    Science.gov (United States)

    Banerjee, Avik; Bhattacharyya, Gautam; Kumar, Nilanjana; Ray, Tirtha Sankar

    2018-03-01

    We systematically study the modifications in the couplings of the Higgs boson, when identified as a pseudo Nambu-Goldstone boson of a strong sector, in the light of LHC Run 1 and Run 2 data. For the minimal coset SO(5)/SO(4) of the strong sector, we focus on scenarios where the standard model left- and right-handed fermions (specifically, the top and bottom quarks) are either in 5 or in the symmetric 14 representation of SO(5). Going beyond the minimal 5 L - 5 R representation, to what we call here the `extended' models, we observe that it is possible to construct more than one invariant in the Yukawa sector. In such models, the Yukawa couplings of the 125 GeV Higgs boson undergo nontrivial modifications. The pattern of such modifications can be encoded in a generic phenomenological Lagrangian which applies to a wide class of such models. We show that the presence of more than one Yukawa invariant allows the gauge and Yukawa coupling modifiers to be decorrelated in the `extended' models, and this decorrelation leads to a relaxation of the bound on the compositeness scale ( f ≥ 640 GeV at 95% CL, as compared to f ≥ 1 TeV for the minimal 5 L - 5 R representation model). We also study the Yukawa coupling modifications in the context of the next-to-minimal strong sector coset SO(6)/SO(5) for fermion-embedding up to representations of dimension 20. While quantifying our observations, we have performed a detailed χ 2 fit using the ATLAS and CMS combined Run 1 and available Run 2 data.

  13. Phenomenology of non-minimal supersymmetric models at linear colliders

    International Nuclear Information System (INIS)

    Porto, Stefano

    2015-06-01

    The focus of this thesis is on the phenomenology of several non-minimal supersymmetric models in the context of future linear colliders (LCs). Extensions of the minimal supersymmetric Standard Model (MSSM) may accommodate the observed Higgs boson mass at about 125 GeV in a more natural way than the MSSM, with a richer phenomenology. We consider both F-term extensions of the MSSM, as for instance the non-minimal supersymmetric Standard Model (NMSSM), as well as D-terms extensions arising at low energies from gauge extended supersymmetric models. The NMSSM offers a solution to the μ-problem with an additional gauge singlet supermultiplet. The enlarged neutralino sector of the NMSSM can be accurately studied at a LC and used to distinguish the model from the MSSM. We show that exploiting the power of the polarised beams of a LC can be used to reconstruct the neutralino and chargino sector and eventually distinguish the NMSSM even considering challenging scenarios that resemble the MSSM. Non-decoupling D-terms extensions of the MSSM can raise the tree-level Higgs mass with respect to the MSSM. This is done through additional contributions to the Higgs quartic potential, effectively generated by an extended gauge group. We study how this can happen and we show how these additional non-decoupling D-terms affect the SM-like Higgs boson couplings to fermions and gauge bosons. We estimate how the deviations from the SM couplings can be spotted at the Large Hadron Collider (LHC) and at the International Linear Collider (ILC), showing how the ILC would be suitable for the model identication. Since our results prove that a linear collider is a fundamental machine for studying supersymmetry phenomenology at a high level of precision, we argue that also a thorough comprehension of the physics at the interaction point (IP) of a LC is needed. Therefore, we finally consider the possibility of observing intense electromagnetic field effects and nonlinear quantum electrodynamics

  14. Phenomenology in Its Original Sense.

    Science.gov (United States)

    van Manen, Max

    2017-05-01

    In this article, I try to think through the question, "What distinguishes phenomenology in its original sense?" My intent is to focus on the project and methodology of phenomenology in a manner that is not overly technical and that may help others to further elaborate on or question the singular features that make phenomenology into a unique qualitative form of inquiry. I pay special attention to the notion of "lived" in the phenomenological term "lived experience" to demonstrate its critical role and significance for understanding phenomenological reflection, meaning, analysis, and insights. I also attend to the kind of experiential material that is needed to focus on a genuine phenomenological question that should guide any specific research project. Heidegger, van den Berg, and Marion provide some poignant exemplars of the use of narrative "examples" in phenomenological explorations of the phenomena of "boredom," "conversation," and "the meaningful look in eye-contact." Only what is given or what gives itself in lived experience (or conscious awareness) are proper phenomenological "data" or "givens," but these givens are not to be confused with data material that can be coded, sorted, abstracted, and accordingly analyzed in some "systematic" manner. The latter approach to experiential research may be appropriate and worthwhile for various types of qualitative inquiry but not for phenomenology in its original sense. Finally, I use the mythical figure of Kairos to show that the famous phenomenological couplet of the epoché-reduction aims for phenomenological insights that require experiential analysis and attentive (but serendipitous) methodical inquiry practices.

  15. Resonant diphoton phenomenology simplified

    International Nuclear Information System (INIS)

    Panico, Giuliano; Vecchi, Luca; Wulzer, Andrea

    2016-01-01

    A framework is proposed to describe resonant diphoton phenomenology at hadron colliders in full generality. It can be employed for a comprehensive model-independent interpretation of the experimental data. Within the general framework, few benchmark scenarios are defined as representative of the various phenomenological options and/or of motivated new physics scenarios. Their usage is illustrated by performing a characterization of the 750 GeV excess, based on a recast of available experimental results. We also perform an assessment of which properties of the resonance could be inferred, after discovery, by a careful experimental study of the diphoton distributions. These include the spin J of the new particle and its dominant production mode. Partial information on its CP-parity can also be obtained, but only for J≥2. The complete determination of the resonance CP properties requires studying the pattern of the initial state radiation that accompanies the resonant diphoton production.

  16. Scrutinizing the alignment limit in two-Higgs-doublet models. II. mH=125 GeV

    Science.gov (United States)

    Bernon, Jérémy; Gunion, John F.; Haber, Howard E.; Jiang, Yun; Kraml, Sabine

    2016-02-01

    In the alignment limit of a multidoublet Higgs sector, one of the Higgs mass eigenstates aligns in field space with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM) Higgs boson. We consider C P -conserving two-Higgs-doublet models (2HDMs) of type I and type II near the alignment limit in which the heavier of the two C P -even Higgs bosons, H , is the SM-like state observed with a mass of 125 GeV, and the couplings of H to gauge bosons approach those of the SM. We review the theoretical structure and analyze the phenomenological implications of this particular realization of the alignment limit, where decoupling of the extra states cannot occur given that the lighter C P -even state h must, by definition, have a mass below 125 GeV. For the numerical analysis, we perform scans of the 2HDM parameter space employing the software packages 2hdmc and lilith, taking into account all relevant pre-LHC constraints, constraints from the measurements of the 125 GeV Higgs signal at the LHC, as well as the most recent limits coming from searches for other Higgs-like states. Implications for Run 2 at the LHC, including expectations for observing the other scalar states, are also discussed.

  17. Muon g−2 in the aligned two Higgs doublet model

    Energy Technology Data Exchange (ETDEWEB)

    Han, Tao [Department of Physics and Astronomy, University of Pittsburgh,Pittsburgh, PA 15260 (United States); Physics Department, Collaborative Innovation Center of Quantum Matter, Tsinghua University,Beijing 100084 (China); Korea Institute for Advanced Study,Seoul 130-722 (Korea, Republic of); Kang, Sin Kyu [School of Liberal Arts, Seoul National University of Science and Technology,Seoul 139-743 (Korea, Republic of); Sayre, Joshua [Department of Physics and Astronomy, University of Pittsburgh,Pittsburgh, PA 15260 (United States)

    2016-02-16

    We study the Two-Higgs-Doublet Model with the aligned Yukawa sector (A2HDM) in light of the observed excess measured in the muon anomalous magnetic moment. We take into account the existing theoretical and experimental constraints with up-to-date values and demonstrate that a phenomenologically interesting region of parameter space exists. With a detailed parameter scan, we show a much larger region of viable parameter space in this model beyond the limiting case Type X 2HDM as obtained before. It features the existence of light scalar states with masses 3 GeV≲m{sub H}≲50 GeV, or  10 GeV≲m{sub A}≲130 GeV, with enhanced couplings to tau leptons. The charged Higgs boson is typically heavier, with 200 GeV≲m{sub H{sup +}}≲630 GeV. The surviving parameter space is forced into the CP-conserving limit by EDM constraints. Some Standard Model observables may be significantly modified, including a possible new decay mode of the SM-like Higgs boson to four taus. We comment on future measurements and direct searches for those effects at the LHC as tests of the model.

  18. The Higgs Portal and Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Assamagan, Ketevi [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, Chien-Yi [Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada); Univ. of Victoria, BC (Canada); Chou, John Paul [Rutgers Univ., Piscataway, NJ (United States); Curtin, David [Univ. of Maryland, College Park, MD (United States); Fedderke, Michael A. [Univ. of Chicago, IL (United States); Gershtein, Yuri [Rutgers Univ., Piscataway, NJ (United States); He, Xiao-Gang [Shanghai Jiao Tong Univ. (China); Klute, Markus [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kozaczuk, Jonathon [TRIUMF, Vancouver, BC (Canada); Kotwal, Ashutosh [Duke Univ., Durham, NC (United States); Lowette, Steven [Vrije Univ., Brussels (Belgium); No, Jose Miguel [Univ. of Sussex, Brighton (United Kingdom); Plehn, Tilman [Heidelberg Univ. (Germany); Qian, Jianming [Univ. of Michigan, Ann Arbor, MI (United States); Ramsey-Musolf, Michael [Univ. of Massachusetts, Amherst, MA (United States); Safonov, Alexei [Texas A & M Univ., College Station, TX (United States); Shelton, Jessie [Univ. of Illinois, Urbana-Champaign, IL (United States); Spannowsky, Michael [Durham Univ. (United Kingdom); Su, Shufang [Univ. of Arizona, Tucson, AZ (United States); Walker, Devin G. E. [Univ. of Washington, Seattle, WA (United States); Willocq, Stephane [Univ. of Massachusetts, Amherst, MA (United States); Winslow, Peter [Univ. of Massachusetts, Amherst, MA (United States)

    2016-04-18

    Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first-order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.

  19. Searching for additional Higgs bosons via Higgs cascades

    Science.gov (United States)

    Gao, Christina; Luty, Markus A.; Mulhearn, Michael; Neill, Nicolás A.; Wang, Zhangqier

    2018-04-01

    The discovery of a 125 GeV Higgs boson at the Large Hadron Collider strongly motivates direct searches for additional Higgs bosons. In a type I two Higgs doublet model there is a large region of parameter space at tan β ≳5 that is currently unconstrained experimentally. We show that the process g g →H →A Z →Z Z h can probe this region, and can be the discovery mode for an extended Higgs sector at the LHC. We analyze 9 promising decay modes for the Z Z h state, and we find that the most sensitive final states are ℓℓℓℓb b , ℓℓj j b b , ℓℓν ν γ γ and ℓℓℓℓ+ missing energy.

  20. Effective approaches in and beyond the MSSM: applications to Higgs physics and dark matter observables

    International Nuclear Information System (INIS)

    Drieu la Rochelle, G.

    2012-01-01

    We have developed in this thesis a method to shed some light on the features of supersymmetry in view of Higgs physics and observables pertaining to dark matter: the effective approach. We have thus investigated the BMSSM framework, an extension of the MSSM - Minimal Supersymmetric Standard Model - that encompasses many different extensions of the MSSM. It turns out that allowing for extra-physics that affect the Higgs sector of the MSSM produces a much richer Higgs phenomenology compared to the MSSM. An important development that we have carried out in the aim of exploiting the LHC performance in the BMSSM framework is the recasting of the Standard Model analyses to BSM (Beyond the Standard Model) theories. Precisely, we have evaluated the accuracy of some approximations as for instance the quadrature sum of different signals to combine the statistical significances and the use of the inclusive predicted cross-sections instead of the exclusive ones. We have also seen that limits on the cross-sections that are obtained by a combination of different subchannels are generically model-dependent. We have then turned to another set of constraints on supersymmetric theories that consists in the dark matter observables. Our work has focused on the precise computation of the relic density in the MSSM. We have decided to introduce once again an effective approach, but whereas the one implemented in the BMSSM aimed at accounting for extra physics beyond the MSSM, this specific one was built to account for radiative corrections brought by MSSM particles. We have performed the implementation of different effective vertices and assessed the robustness of the approach in the case of annihilation of neutralinos to fermions. We have found that the full one-loop result was very well approximated in the case of a bi no-like neutralino, where the discrepancy between both calculations was found to be less than 2%. We have also discussed the case of the Higgsino's-like neutralino with

  1. Search for neutral and charged BSM Higgs bosons with the ATLAS detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00376986; The ATLAS collaboration

    2017-01-01

    Several theories beyond the Standard Model, like the EWS or 2HDM models, predict the existence of high mass neutral or charged Higgs particles. In this presentation the latest ATLAS results on searches for these particles will be discussed.

  2. Search for neutral and charged BSM Higgs Bosons with the ATLAS detector

    CERN Document Server

    {A}lvarez Piqueras, Dami{a}n; The ATLAS collaboration

    2017-01-01

    Several theories beyond the Standard Model, like the EWS or 2HDM models, predict the existence of high mass neutral or charged Higgs particles. In this presentation the latest ATLAS results on searches for these particles will be discussed.

  3. Implications of Higgs searches on the four-generation standard model.

    Science.gov (United States)

    Kuflik, Eric; Nir, Yosef; Volansky, Tomer

    2013-03-01

    Within the four-generation standard model, the Higgs couplings to gluons and to photons deviate in a significant way from the predictions of the three-generation standard model. As a consequence, large departures in several Higgs production and decay channels are expected. Recent Higgs search results, presented by ATLAS, CMS, and CDF, hint on the existence of a Higgs boson with a mass around 125 GeV. Using these results and assuming such a Higgs boson, we derive exclusion limits on the four-generation standard model. For m(H)=125 GeV, the model is excluded above 99.95% confidence level. For 124.5 GeV≤m(H)≤127.5 GeV, an exclusion limit above 99% confidence level is found.

  4. Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00444174; The ATLAS collaboration

    2015-01-01

    Some recent searches for the Higgs boson in the context of beyond the Standard Model, performed by the ATLAS experiment are presented: high mass Higgs boson searches, lepton flavour violating Higgs decay, NMSSM, con- straint from the search for three photons. The interpretation based on the measurements of Higgs couplings are shown, along with the constraint on the Higgs boson invisible decays. Except the latter has some part using both full √s = 7 TeV and √s = 8 TeV data, the rest are performed with the √s = 8 TeV data of proton-proton collisions collected by the ATLAS experiment. No sig- nificant excess of data over the predicted background is observed in all those searches. Limits are placed in certain quantities depending on the searches.

  5. The Higgs mechanism and the origin of mass

    Science.gov (United States)

    Djouadi, Abdelhak

    2012-06-01

    The Higgs mechanism plays a key role in the physics of elementary particles: in the context of the Standard Model, the theory which describes in a unified framework the electromagnetic, weak and strong nuclear interactions, it allows for the generation of particle masses while preserving the fundamental symmetries of the theory. This mechanism predicts the existence of a new type of particle, the scalar Higgs boson, with unique characteristics. The detection of this particle and the study of its fundamental properties is a major goal of high-energy particle colliders, such as the CERN Large Hadron Collider or LHC.

  6. What is the probability of the Higgs boson discovery?

    Energy Technology Data Exchange (ETDEWEB)

    Unzicker, Alexander [Pestalozzi-Gymnasium Muenchen (Germany)

    2010-07-01

    The standard model of particle physics requires the existence of the Higgs boson which provides a mechanism for the appearance of masses. Its detection is one of the most important goals of high energy physics, and enormous efforts have been undertaken at Tevatron and specially at the Large Hadron Collider. But how sure can we be that the Higgs exits at all? At such controversial questions, the German philosopher Immanuel Kant recommended a bet, and nowadays this can be realized using online prediction markets like Intrade.com. Such platforms have been proven useful for giving estimates of unknown probabilities, and the application for evaluating scientific research is discussed in general.

  7. Results on SUSY and Higgs searches at CMS

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    We present the results of searches for Supersymmetry and the Higgs boson performed using data collected in 2010 by the CMS experiment at the LHC in pp-collisions at a centre-of-mass energy of 7 TeV. Searches for Supersymmetry are performed in all-hadronic final states with jets and missing transverse energy and in final states including one or more isolated leptons or photons. No evidence for new physics is observed and limits are set on the predictions of a range of Supersymmetric scenarios. The results of searches for the Higgs boson are presented and limits set.

  8. Gluon fusion Higgs production in the CP violating MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Shruti; Liebler, Stefan; Weiglein, Georg [DESY, Hamburg (Germany)

    2016-07-01

    The MSSM with complex parameters has emerged as an attractive SUSY candidate providing new sources of CP-violation, which are well motivated in the context of the observed imbalance between matter and antimatter in the universe. In order to study the effects of the complex parameters, which enter via loop contributions, an accurate prediction for the Higgs production cross-section is required. In this talk, we present a study of these effects carried out with an implementation in the program SusHi linked to FeynHiggs.

  9. Neutral Scalar Higgs searches using Vector Boson Fusion at ATLAS

    CERN Document Server

    De Jong, J K; Pinfold, J L

    2005-01-01

    The Higgs boson is the last undiscovered particle predicted by the Standard Model. Its discovery is key to our understanding of the electroweak symmetry breaking process and the origin of mass. The primary purpose of the ATLAS detector at the Large Hadron Collider is the discovery of this particle. This thesis evaluates the discovery potential of the ATLAS experiment for a Heavy Neutral Scalar Higgs boson, $\\text{M}_{H} \\ge 170 ~\\text{\\GEVCC}$, produced through vector boson fusion and decaying through the four physics channels : H$\\rightarrow$ZZ$\\rightarrow l^{+}l^{-}$+jj and H$\\rightarrow$WW$\\rightarrow l\

  10. The God's particle - In the search for the Higgs boson

    International Nuclear Information System (INIS)

    Baggot, Jim

    2013-01-01

    This document briefly presents a book in which the author reports the quest of scientists in the elaboration of a model which could explain matter structure at its most elementary level, until the discovery of the famous Higgs boson at the LHC in July 2012. He explains the nature of the Higgs boson and why its discovery is so important because it confirms a model which has been progressively elaborated, discovery after discovery, and which also predicted the existence of a boson giving their mass to the other particles. In other words, without this boson, the universe could not just be what it is

  11. Quantum chromodynamics effects in electroweak and Higgs physics

    Indian Academy of Sciences (India)

    Several examples of the often intricate effects of higher-order quantum chromodynamics (QCD) corrections on predictions for hadron-collider observables, are discussed, using the production of electroweak gauge boson and the Standard Model Higgs boson as examples. Particular attention is given to the interplay of QCD ...

  12. Electroweak and Higgs boson production at the LHC

    Directory of Open Access Journals (Sweden)

    Lazopoulos Achilleas

    2013-05-01

    Full Text Available I summarize very briefly the status of theory predictions for the production of electroweak and Higgs bosons at the LHC, highlighting recent developments and issues that have attracted the interest of the theory community. The focus is on inclusive and fixed order differential computations and related developments in parton showers are not discussed at all in this contribution.

  13. Higgs inflation, seesaw physics and fermion dark matter

    Directory of Open Access Journals (Sweden)

    Nobuchika Okada

    2015-07-01

    Full Text Available We present an inflationary model in which the Standard Model Higgs doublet field with non-minimal coupling to gravity drives inflation, and the effective Higgs potential is stabilized by new physics which includes a dark matter particle and right-handed neutrinos for the seesaw mechanism. All of the new particles are fermions, so that the Higgs doublet is the unique inflaton candidate. With central values for the masses of the top quark and the Higgs boson, the renormalization group improved Higgs potential is employed to yield the scalar spectral index ns≃0.968, the tensor-to-scalar ratio r≃0.003, and the running of the spectral index α=dns/dln⁡k≃−5.2×10−4 for the number of e-folds N0=60 (ns≃0.962, r≃0.004, and α≃−7.5×10−4 for N0=50. The fairly low value of r≃0.003 predicted in this class of models means that the ongoing space and land based experiments are not expected to observe gravity waves generated during inflation.

  14. Discovery of the Higgs Boson Decaying to Two Photons

    CERN Document Server

    AUTHOR|(CDS)2075371; Branson, James; Pieri, Marco

    2014-09-10

    The Standard Model (SM) of particle physics fundamentally relies on the existence of the Higgs boson. This massive particle is a relic of the underlying and hidden Higgs field, whose transformation into the Higgs boson provides mass to weak bosons and all massive fermions in the SM. This particle has been long-sought and finally using data from proton-proton collisions at the LHC, CMS and ATLAS experiments have discovered a particle which is compatible with the SM Higgs boson. Presented here is the development of one of the discovery channels, $\\mathrm{H}\\rightarrow\\gamma\\gamma$, and the final $\\mathrm{H}\\rightarrow\\gamma\\gamma$ analysis and results using the full luminosity of the LHC Run 1 dataset $\\sim$25 $\\mathrm{fb}^{-1}$ at 7 or 8 TeV center of mass energy. The observed (expected) significance of this di-photon excess in the final analysis is $5.7\\sigma$ ($5.2\\sigma$) with a measured signal strength of $\\sigma / \\sigma_{SM} = 1.14^{+0.26}_{-0.23}$. The mass of this Higgs boson is not predicted by t...

  15. The RG-improved Twin Higgs effective potential at NNLL

    Energy Technology Data Exchange (ETDEWEB)

    Greco, Davide; Mimouni, Kin [Institut de Théorie des Phénomènes Physiques, EPFL,Route de la Sorge, Lausanne, CH-1015 (Switzerland)

    2016-11-18

    We present the Renormalization Group improvement of the Twin Higgs effective potential at cubic order in logarithmic accuracy. We first introduce a model-independent low-energy effective Lagrangian that captures both the pseudo-Nambu-Goldstone boson nature of the Higgs field and the twin light degrees of freedom charged under a copy of the Standard Model. We then apply the background field method to systematically re-sum all the one loop diagrams contributing to the potential. We show how this technique can be efficient to implicitly renormalize the higher-dimensional operators in the twin sector without classifying all of them. A prediction for the Higgs mass in the Twin Higgs model is derived and found to be of the order of M{sub H}∼120 GeV with an ultraviolet cut-off m{sub ∗}∼10–20 TeV. Irrespective of any possible ultraviolet completion of the low-energy Lagrangian, the infrared degrees of freedom alone are therefore enough to account for the observed value of the Higgs mass through running effects.

  16. Searches for standard model Higgs boson and supersymmetry - Trigger studies and software tools development for new phenomena in the DO experiment; Recherche du boson de Higgs et de la supersymetrie - Conditions de declenchement pour phenomenes rares dans l'experience DO

    Energy Technology Data Exchange (ETDEWEB)

    Duperrin, A

    2007-04-15

    This document presents a summary of my research work during the past 7 years for the preparation of the D0 experiment at Fermilab and the analysis of the data collected at the Tevatron hadron collider. It mainly focuses on 2 topics: trigger and direct search for new phenomena, particularly on supersymmetry and standard model Higgs boson searches. This document is divided into 5 chapters: 1) the phenomenology of the standard model and beyond, 2) the phenomenology of pp-bar events, 3) the Tevatron and D0 detector, 4) the trigger system and data acquisition, and 5) data analysis: search for supersymmetry and Higgs boson.

  17. Higgs properties and decays, searches for high mass Higgs boson and di-Higgs production

    CERN Document Server

    Cadamuro, Luca

    2018-01-01

    The study of the scalar sector of the standard model of particle physics is one of the main goals of the LHC physics programme.A precise characterisation of the Higgs boson, searches for extensions of the scalar sector, and the study of Higgs boson pair production are complementary in this exploration.This document describes the status of Higgs boson physics analyses performed by the ATLAS and CMS Collaborations, focusing on the latest results from pp collisions at sqrt(s) = 13 TeV recorded in 2016, for an integrated luminosity of about 36 fb-1.

  18. Higgs vacuum stability and modified chaotic inflation

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Abhijit Kumar, E-mail: abhijit.saha@iitg.ernet.in; Sil, Arunansu, E-mail: asil@iitg.ernet.in

    2017-02-10

    The issue of electroweak vacuum stability is studied in presence of a scalar field which participates in modifying the minimal chaotic inflation model. It is shown that the threshold effect on the Higgs quartic coupling originating from the Higgs–inflaton sector interaction can essentially make the electroweak vacuum stable up to the Planck scale. On the other hand we observe that the new physics parameters in this combined framework are enough to provide deviation from the minimal chaotic inflation predictions so as to keep it consistent with recent observation by Planck 2015.

  19. Inflation and pseudo-Goldstone Higgs boson

    DEFF Research Database (Denmark)

    Alanne, Tommi; Sannino, Francesco; Tenkanen, Tommi

    2017-01-01

    We consider inflation within a model framework where the Higgs boson arises as a pseudo-Goldstone boson associated with the breaking of a global symmetry at a scale significantly larger than the electroweak one. We show that in such a model the scalar self-couplings can be parametrically suppressed...... and, consequently, the nonminimal couplings to gravity can be of order one or less, while the inflationary predictions of the model remain compatible with the precision cosmological observations. Furthermore, in the model we study, the existence of the electroweak scale is entirely due to the inflaton...

  20. Top quark and Higgs boson masses from wormhole physics

    International Nuclear Information System (INIS)

    Harris, B.A.; Joshi, G.C.

    1994-01-01

    We bring together quantum field theory on S 4 with the Coleman wormhole hypothesis, which imposes constraints on terms in the gravitational Lagrangian. In particular, we investigate the effect of matter fields on the trace anomaly, which is related to the (curvature) 2 terms, by the use of the renormalization group equations. We consider a toy model of a nonconformally coupled Higgs boson to a single ''top'' quark. By numerically solving the renormalization group equations for the couplings of the model, we can find preferred values of the particle masses for various values of the bare nonconformal coupling. By making the ad hoc assumption that the tree-level, Higgs boson treace anomaly vanishes on shell, a unique prediction can be made within this model for the masses of both the Higgs boson and the top quark