The correlation matrix of Higgs rates at the LHC

CERN Document Server

Arbey, Alexandre; Mahmoudi, Farvah; Moreau, Grégory

2016-11-17

The imperfect knowledge of the Higgs boson LHC cross sections and decay rates constitutes a critical systematic uncertainty in the study of the Higgs boson properties. We show that the full covariance matrix between the Higgs rates can be determined from the most elementary sources of uncertainty by a direct application of probability theory. We evaluate the error magnitudes and full correlation matrix on the set of Higgs cross sections and partial decay widths at $\\sqrt{s}=7$, $8$, $13$ and $14$~TeV, which are provided in ancillary files. The impact of this correlation matrix on the global fits is illustrated with the latest $7$+$8$ TeV Higgs dataset.

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 ...

Probing baryogenesis through the Higgs boson self-coupling

Science.gov (United States)

Reichert, M.; Eichhorn, A.; Gies, H.; Pawlowski, J. M.; Plehn, T.; Scherer, M. M.

2018-04-01

The link between a modified Higgs self-coupling and the strong first-order phase transition necessary for baryogenesis is well explored for polynomial extensions of the Higgs potential. We broaden this argument beyond leading polynomial expansions of the Higgs potential to higher polynomial terms and to nonpolynomial Higgs potentials. For our quantitative analysis we resort to the functional renormalization group, which allows us to evolve the full Higgs potential to higher scales and finite temperature. In all cases we find that a strong first-order phase transition manifests itself in an enhancement of the Higgs self-coupling by at least 50%, implying that such modified Higgs potentials should be accessible at the LHC.

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)

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.

The correlation matrix of Higgs rates at the LHC

Energy Technology Data Exchange (ETDEWEB)

Arbey, Alexandre [Univ Lyon, Univ Lyon 1, ENS de Lyon, CNRS,Centre de Recherche Astrophysique de Lyon UMR5574,F-69230 Saint-Genis-Laval (France); Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Fichet, Sylvain [ICTP-SAIFR & IFT-UNESP,Rua Dr. Bento Teobaldo Ferraz 271, Sao Paulo (Brazil); Mahmoudi, Farvah [Univ Lyon, Univ Lyon 1, ENS de Lyon, CNRS,Centre de Recherche Astrophysique de Lyon UMR5574,F-69230 Saint-Genis-Laval (France); Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Moreau, Grégory [Laboratoire de Physique Théorique, CNRS, Université Paris-Sud 11, Bât. 210, F-91405 Orsay Cedex (France)

2016-11-17

The imperfect knowledge of the Higgs boson decay rates and cross sections at the LHC constitutes a critical systematic uncertainty in the study of the Higgs boson properties. We show that the full covariance matrix between the Higgs rates can be determined from the most elementary sources of uncertainty by a direct application of probability theory. We evaluate the error magnitudes and full correlation matrix on the set of Higgs cross sections and branching ratios at √s=7, 8, 13 and 14 TeV, which are provided in ancillary files. The impact of this correlation matrix on the global fits is illustrated with the latest 7+8 TeV Higgs dataset.

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

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

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.

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).

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).

Non-SM Exotic Higgs: Beyond SM and MSSM

Directory of Open Access Journals (Sweden)

Lacaprara Stefano

2013-05-01

Full Text Available A review of the searches for exotic Higgs boson beyond standard model and minimal supersymmetric standard model (MSSM, from experiments at the Tevatron and LHC, is presented. Several different models have been considered, including extensions to standard model with fourth generation of fermions, fermiophobic Higgs, next-to-MSSM models, seesaw type-II, and rare decay of Higgs boson to hidden sector. For next-to- MSSM models several final states have been considered, including light pseudo-scalar Higgs decay into taus, muons, and photons, as well as charged Higgs boson. The searches has been performed with re-interpretation of results from standard model Higgs search as well as on new signatures.

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.)

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.

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.)

The ATLAS Higgs machine learning challenge

CERN Document Server

Davey, W; The ATLAS collaboration; Rousseau, D; Cowan, G; Kegl, B; Germain-Renaud, C; Guyon, I

2014-01-01

High Energy Physics has been using Machine Learning techniques (commonly known as Multivariate Analysis) since the 90's with Artificial Neural Net for example, more recently with Boosted Decision Trees, Random Forest etc... Meanwhile, Machine Learning has become a full blown field of computer science. With the emergence of Big Data, Data Scientists are developing new Machine Learning algorithms to extract sense from large heterogeneous data. HEP has exciting and difficult problems like the extraction of the Higgs boson signal, data scientists have advanced algorithms: the goal of the HiggsML project is to bring the two together by a “challenge”: participants from all over the world and any scientific background can compete online ( https://www.kaggle.com/c/higgs-boson ) to obtain the best Higgs to tau tau signal significance on a set of ATLAS full simulated Monte Carlo signal and background. Winners with the best scores will receive money prizes ; authors of the best method (most usable) will be invited t...

Search for Higgs bosons beyond the Standard Model

Directory of Open Access Journals (Sweden)

Mankel Rainer

2015-01-01

Full Text Available While the existence of a Higgs boson with a mass near 125 GeV has been clearly established, the detailed structure of the entire Higgs sector is yet unclear. Beyond the standard model interpretation, various scenarios for extended Higgs sectors are being considered. Such options include the minimal and next-to-minimal supersymmetric extensions (MSSM and NMSSM of the standard model, more generic Two-Higgs Doublet models (2HDM, as well as truly exotic Higgs bosons decaying e.g. into totally invisible final states. This article presents recent results from the CMS experiment.

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.

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.

Early Universe Higgs dynamics in the presence of the Higgs-inflaton and non-minimal Higgs-gravity couplings

Energy Technology Data Exchange (ETDEWEB)

Ema, Yohei [Department of Physics, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Karčiauskas, Mindaugas [University of Jyväskylä, Department of Physics, P.O. Box 35 (YFL), FI-40014, Jyväskylä (Finland); Lebedev, Oleg; Zatta, Marco, E-mail: ema@hep-th.phys.s.u-tokyo.ac.jp, E-mail: mindaugas.m.karciauskas@jyu.fi, E-mail: oleg.lebedev@helsinki.fi, E-mail: marco.zatta@helsinki.fi [University of Helsinki and Helsinki Institute of Physics, P.O. Box 64, FI-00014, Helsinki (Finland)

2017-06-01

Apparent metastability of the electroweak vacuum poses a number of cosmological questions. These concern evolution of the Higgs field to the current vacuum, and its stability during and after inflation. Higgs-inflaton and non-minimal Higgs-gravity interactions can make a crucial impact on these considerations potentially solving the problems. In this work, we allow for these couplings to be present simultaneously and study their interplay. We find that different combinations of the Higgs-inflaton and non-minimal Higgs-gravity couplings induce effective Higgs mass during and after inflation. This crucially affects the Higgs stability considerations during preheating. In particular, a wide range of the couplings leading to stable solutions becomes allowed.

A fast and robust iterative algorithm for prediction of RNA pseudoknotted secondary structures

Science.gov (United States)

2014-01-01

Background Improving accuracy and efficiency of computational methods that predict pseudoknotted RNA secondary structures is an ongoing challenge. Existing methods based on free energy minimization tend to be very slow and are limited in the types of pseudoknots that they can predict. Incorporating known structural information can improve prediction accuracy; however, there are not many methods for prediction of pseudoknotted structures that can incorporate structural information as input. There is even less understanding of the relative robustness of these methods with respect to partial information. Results We present a new method, Iterative HFold, for pseudoknotted RNA secondary structure prediction. Iterative HFold takes as input a pseudoknot-free structure, and produces a possibly pseudoknotted structure whose energy is at least as low as that of any (density-2) pseudoknotted structure containing the input structure. Iterative HFold leverages strengths of earlier methods, namely the fast running time of HFold, a method that is based on the hierarchical folding hypothesis, and the energy parameters of HotKnots V2.0. Our experimental evaluation on a large data set shows that Iterative HFold is robust with respect to partial information, with average accuracy on pseudoknotted structures steadily increasing from roughly 54% to 79% as the user provides up to 40% of the input structure. Iterative HFold is much faster than HotKnots V2.0, while having comparable accuracy. Iterative HFold also has significantly better accuracy than IPknot on our HK-PK and IP-pk168 data sets. Conclusions Iterative HFold is a robust method for prediction of pseudoknotted RNA secondary structures, whose accuracy with more than 5% information about true pseudoknot-free structures is better than that of IPknot, and with about 35% information about true pseudoknot-free structures compares well with that of HotKnots V2.0 while being significantly faster. Iterative HFold and all data used in

Extended Higgs sectors in radiative neutrino models

Directory of Open Access Journals (Sweden)

Oleg Antipin

2017-05-01

Full Text Available Testable Higgs partners may be sought within the extensions of the SM Higgs sector aimed at generating neutrino masses at the loop level. We study a viability of extended Higgs sectors for two selected models of radiative neutrino masses: a one-loop mass model, providing the Higgs partner within a real triplet scalar representation, and a three-loop mass model, providing it within its two-Higgs-doublet sector. The Higgs sector in the one-loop model may remain stable and perturbative up to the Planck scale, whereas the three-loop model calls for a UV completion around 106 GeV. Additional vector-like lepton and exotic scalar fields, which are required to close one- and three-loop neutrino-mass diagrams, play a decisive role for the testability of the respective models. We constrain the parameter space of these models using LHC bounds on diboson resonances.

Higgs pair production in the CP-violating two-Higgs-doublet model

Science.gov (United States)

Bian, Ligong; Chen, Ning; Jiang, Yun

2017-12-01

The SM-like Higgs pair production is discussed in the framework of the general CP-violating two-Higgs-doublet model, where we find that the CP-violating mixing angles can be related to the Higgs self-couplings. Therefore, the future experimental searches for Higgs boson pairs can be constrained by the improved precision of the electric dipole moment measurements. Based on a series of constraints of the SM-like Higgs boson signal fits, the perturbative unitarity and stability bounds to the Higgs potential, and the most recent LHC searches for heavy Higgs bosons, we suggest a set of benchmark models for the future high-energy collider searches for Higgs pair production. The e+e- colliders operating at s = (500GeV,1 TeV) are capable of measuring the Higgs cubic self-couplings of the benchmark models directly. We also estimate the cross sections of the resonance contributions to the Higgs pair productions for the benchmark models at the future LHC and SppC/FCC-hh runs.

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.

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

Who will catch the Higgs boson?

International Nuclear Information System (INIS)

Colas, P.; Tuchming, B.

2004-01-01

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 the Higgs boson exists it will be detected at LHC because this equipment covers completely the energy range in which the Higgs boson is suspected to exist. (A.C.)

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.)

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.)

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.

Invisible Higgs decays from Higgs-graviscalar mixing

International Nuclear Information System (INIS)

Dominici, Daniele; Gunion, John F.

2009-01-01

We recompute the invisible Higgs decay width arising from Higgs-graviscalar mixing in the Arkani-Hamed, Dimopoulos, Dvali model, comparing the original derivation in the nondiagonal mass basis to that in a diagonal mass basis. The results obtained are identical (and differ by a factor of 2 from the original calculation) but the diagonal-basis derivation is pedagogically useful for clarifying the physics of the invisible width from mixing. We emphasize that both derivations make it clear that a direct scan in energy for a process such as WW→WW mediated by Higgs plus graviscalar intermediate resonances would follow a single Breit-Wigner form with total width given by Γ tot =Γ h SM +Γ invisible . We also compute the additional contributions to the invisible width due to direct Higgs to graviscalar-pair decays. We find that the invisible width due to the latter is relatively small, unless the Higgs mass is comparable to or larger than the effective extra-dimensional Planck mass.

Can the 125 GeV Higgs be the Little Higgs?

Energy Technology Data Exchange (ETDEWEB)

Reuter, J.; Tonini, M

2012-12-15

After the discovery of the Higgs-like boson by the LHC 2012 it is the most important task to check whether this new particle is the Standard Model Higgs boson or something else. In this paper, we study whether the 125 GeV boson could be the pseudo- Goldstone boson of Little Higgs models. We derive limits on the parameter space of several Little Higgs models (simple group and product group models, with and without T-parity), both from the experimental data from ATLAS and CMS about the different Higgs discovery channel and the electroweak precision observables. We perform a fit of several Little Higgs models to all electroweak parameters from measurements of SLC, LEP, Tevatron, and LHC. For the Higgs searches, we include all available data from the summer conferences 2012 as well as the update from December 2012.

Trilinear Higgs couplings in the two Higgs doublet model with CP violation

International Nuclear Information System (INIS)

Osland, Per; Pandita, P. N.; Selbuz, Levent

2008-01-01

We carry out a detailed analysis of the general two Higgs doublet model with CP violation. We describe two different parametrizations of this model, and then study the Higgs boson masses and the trilinear Higgs couplings for these two parametrizations. Within a rather general model, we find that the trilinear Higgs couplings have a significant dependence on the details of the model, even when the lightest Higgs boson mass is taken to be a fixed parameter. We include radiative corrections in the one-loop effective potential approximation in our analysis of the Higgs boson masses and the Higgs trilinear couplings. The one-loop corrections to the trilinear couplings of the two Higgs doublet model also depend significantly on the details of the model, and can be rather large. We study quantitatively the trilinear Higgs couplings, and show that these couplings are typically several times larger than the corresponding standard model trilinear Higgs coupling in some regions of the parameter space. We also briefly discuss the decoupling limit of the two Higgs doublet model.

Neutral Naturalness from Orbifold Higgs Models

Science.gov (United States)

Craig, Nathaniel; Knapen, Simon; Longhi, Pietro

2015-02-01

We present a general class of natural theories in which the Higgs boson is a pseudo-Goldstone boson in an orbifolded gauge theory. The symmetry protecting the Higgs boson at low energies is an accidental global symmetry of the quadratic action, rather than a full continuous symmetry. The lightest degrees of freedom protecting the weak scale carry no standard model (SM) quantum numbers and interact with visible matter principally through the Higgs portal. This opens the door to the systematic study of "neutral naturalness": natural theories with SM-neutral states that are as yet untested by the LHC.

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).

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.)

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 ...

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.

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.

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.)

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.)

The standard model Higgs search at the large hadron collider

Indian Academy of Sciences (India)

Strategies are being developed to look for signatures of Higgs boson and measure its properties. In this paper results from full detector simulation-based studies on Higgs discovery from both ATLAS and CMS experiments at the LHC will be presented. Results of simulation studies on Higgs coupling measurement at LHC ...

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)

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.)

Hybrid Higgs inflation: The use of disformal transformation

Science.gov (United States)

Sato, Seiga; Maeda, Kei-ichi

2018-04-01

We propose a hybrid type of the conventional Higgs inflation and new Higgs inflation models. We perform a disformal transformation into the Einstein frame and analyze the background dynamics and the cosmological perturbations in the truncated model, in which we ignore the higher-derivative terms of the Higgs field. From the observed power spectrum of the density perturbations, we obtain the constraint on the nonminimal coupling constant ξ and the mass parameter M in the derivative coupling. Although the primordial tilt ns in the hybrid model barely changes, the tensor-to-scalar ratio r moves from the value in the new Higgs inflationary model to that in the conventional Higgs inflationary model as |ξ | increases. We confirm our results by numerical analysis by ADM formalism of the full theory in the Jordan frame.

Higgs particles interacting via a scalar Dark Matter field

Directory of Open Access Journals (Sweden)

Bhattacharya Yajnavalkya

2016-01-01

Full Text Available We study a system of two Higgs particles, interacting via a scalar Dark Matter mediating field. The variational method in the Hamiltonian formalism of QFT is used to derive relativistic wave equations for the two-Higgs system, using a truncated Fock-space trial state. Approximate solutions of the two-body equations are used to examine the existence of Higgs bound states.

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.

The Higgs-strahlung and double Higgs-strahlung production in the left-right twin Higgs model at the ILC

International Nuclear Information System (INIS)

Yao-Bei, Liu; Hong-Mei, Han; Xue-Lei, Wang

2008-01-01

The Higgs-strahlung process e + e - → ZH and the double Higgs-strahlung process e + e - → ZHH are very important for studying Higgs boson properties and the Higgs self-coupling in the high-energy e + e - collider (ILC). We calculate the contributions of the left-right twin Higgs (LRTH) model to these processes and find that, in the favorable parameter spaces, the LRTH model can generate significant corrections to the production cross-section of these processes. We expect that the possible signals of the LRTH model can be detected via these processes in the future ILC experiments. (authors)

Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson ...

Indian Academy of Sciences (India)

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 tan and A. We observe that at fixed ...

Beyond the Standard Model Higgs searches at the LHC

CERN Document Server

Meridiani, P

2015-01-01

The Run I at the LHC marks the birth of the "Higgs physics", a path which will be followed at its full extent in the future runs of the LHC. Indeed there are two complementary paths to be followed to new physics in the Higgs sector: precision measurements of the Higgs properties (couplings, mass, spin and parity), where new physics can manifest as deviation from the Standard Model, or direct search for processes not foreseen in the Standard Model (Higgs decays not foreseen in the Standard Model, additional scalars which would indicate an extended Higgs sector). The current status of these studies at the LHC is presented, focussing in particular on the direct searches for rare or invisible Higgs decays or for an extended Higgs sector. The results are based on the analysis of the proton-proton collisions at 7 and 8 TeV center-of-mass energy at the LHC by the ATLAS and CMS collaborations.

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.

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.

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.

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.

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...

Little Higgs model limits from LHC - Input for Snowmass 2013

International Nuclear Information System (INIS)

Reuter, Juergen; Tonini, Marco; Vries, Maikel de

2013-07-01

The status of the most prominent model implementations of the Little Higgs paradigm, the Littlest Higgs with and without discrete T parity as well as the Simplest Little Higgs are reviewed. For this, we are taking into account a fit to 21 electroweak precision observables from LEP, SLC, Tevatron together with the full 25 fb -1 of Higgs data reported from ATLAS and CMS at Moriond 2013. We also - focusing on the Littlest Higgs with T parity - include an outlook on corresponding direct searches at the 8 TeV LHC and their competitiveness with the EW and Higgs data regarding their exclusion potential. This contribution to the Snowmass procedure serves as a guideline which regions in parameter space of Little Higgs models are still compatible for the upcoming LHC runs and future experiments at the energy frontier. For this we propose two different benchmark scenarios for the Littlest Higgs with T parity, one with heavy mirror quarks, one with light ones.

Little Higgs model limits from LHC - Input for Snowmass 2013

Energy Technology Data Exchange (ETDEWEB)

Reuter, Juergen; Tonini, Marco; Vries, Maikel. de

2013-07-15

The status of the most prominent model implementations of the Little Higgs paradigm, the Littlest Higgs with and without discrete T parity as well as the Simplest Little Higgs are reviewed. For this, we are taking into account a fit to 21 electroweak precision observables from LEP, SLC, Tevatron together with the full 25 fb{sup -1} of Higgs data reported from ATLAS and CMS at Moriond 2013. We also - focusing on the Littlest Higgs with T parity - include an outlook on corresponding direct searches at the 8 TeV LHC and their competitiveness with the EW and Higgs data regarding their exclusion potential. This contribution to the Snowmass procedure serves as a guideline which regions in parameter space of Little Higgs models are still compatible for the upcoming LHC runs and future experiments at the energy frontier. For this we propose two different benchmark scenarios for the Littlest Higgs with T parity, one with heavy mirror quarks, one with light ones.

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

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.)

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.

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

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)

Upper and lower Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa model

International Nuclear Information System (INIS)

Gerhold, Philipp Frederik Clemens

2009-01-01

Motivated by the advent of the Large Hadron Collider (LHC) the aim of the present work is the non-perturbative determination of the cutoff-dependent upper and lower mass bounds of the Standard Model Higgs boson based on first principle calculations, in particular not relying on additional information such as the triviality property of the Higgs- Yukawa sector or indirect arguments like vacuum stability considerations. For that purpose the lattice approach is employed to allow for a non-perturbative investigation of a chirally invariant lattice Higgs-Yukawa model, serving here as a reasonable simplification of the full Standard Model, containing only those fields and interactions which are most essential for the intended Higgs boson mass determination. These are the complex Higgs doublet as well as the top and bottom quark fields and their mutual interactions. To maintain the chiral character of the Standard Model Higgs-fermion coupling also on the lattice, the latter model is constructed on the basis of the Neuberger overlap operator, obeying then an exact global lattice chiral symmetry. Respecting the fermionic degrees of freedom in a fully dynamical manner by virtue of a PHMC algorithm appropriately adapted to the here intended lattice calculations, such mass bounds can indeed be established with the aforementioned approach. Supported by analytical calculations performed in the framework of the constraint effective potential, the lower bound is found to be approximately m low H (Λ)=80 GeV at a cutoff of Λ=1000 GeV. The emergence of a lower Higgs boson mass bound is thus a manifest property of the pure Higgs-Yukawa sector that evolves directly from the Higgs-fermion interaction for a given set of Yukawa coupling constants. Its quantitative size, however, turns out to be non-universal in the sense, that it depends on the specific form, for instance, of the Higgs boson self-interaction. The upper Higgs boson mass bound is then established in the strong coupling

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.

Higgs pair production at NLO QCD for CP-violating Higgs sectors

Science.gov (United States)

Gröber, R.; Mühlleitner, M.; Spira, M.

2017-12-01

Higgs pair production through gluon fusion is an important process at the LHC to test the dynamics underlying electroweak symmetry breaking. Higgs sectors beyond the Standard Model (SM) can substantially modify this cross section through novel couplings not present in the SM or the on-shell production of new heavy Higgs bosons that subsequently decay into Higgs pairs. CP violation in the Higgs sector is important for the explanation of the observed matter-antimatter asymmetry through electroweak baryogenesis. In this work we compute the next-to-leading order (NLO) QCD corrections in the heavy top quark limit, including the effects of CP violation in the Higgs sector. We choose the effective theory (EFT) approach, which provides a rather model-independent way to explore New Physics (NP) effects by adding dimension-6 operators, both CP-conserving and CP-violating ones, to the SM Lagrangian. Furthermore, we perform the computation within a specific UV-complete model and choose as benchmark model the general 2-Higgs-Doublet Model with CP violation, the C2HDM. Depending on the dimension-6 coefficients, the relative NLO QCD corrections are affected by several per cent through the new CP-violating operators. This is also the case for SM-like Higgs pair production in the C2HDM, while the relative QCD corrections in the production of heavier C2HDM Higgs boson pairs deviate more strongly from the SM case. The absolute cross sections both in the EFT and the C2HDM can be modified by more than an order of magnitude. In particular, in the C2HDM the resonant production of Higgs pairs can by far exceed the SM cross section.

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.

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.)

Higgs-Like Particle due to Revised Quantum Electrodynamics

Directory of Open Access Journals (Sweden)

Lehnert B.

2013-07-01

Full Text Available A Higgs-like particle having zero net electric charge, zero spin, and a nonzero rest mass can be deduced from an earlier elaborated revised quantum electrodynamical theory which is based on linear symmetry breaking through a nonzero electric field divergence in the vacuum state. This special particle is obtained from a composite longitudinal solution based on a zero magnetic field strength and on a nonzero divergence but a vanishing curl of the electric field strength. The present theory further differs from that of the nonlinear spontaneously broken symmetry by Higgs, in which elementary particles obtain their masses through an interaction with the Higgs field. An experimental proof of the basic features of a Higgs-like particle thus supports the present theory, but does not for certain confirm the process which would generate massive particles through a Higgs field

Mass Limit for the standard model Higgs boson with the full LEP I ALEPH data sample

CERN Document Server

Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Büscher, V; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

1996-01-01

background from the electroweak process e+e- --> l+ l- q qbar. This search results in a 95% C.L. lower limit on the Higgs boson mass of $63.9$~\\Gcs. The reaction e+e- --> HZ* is used to search for the standard model Higgs boson in the H nu nubar and the H l+ l- channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the H mu+ mu- channel, in agreement with the expected

Mass limit for the standard model Higgs boson with the full LEP I ALEPH data sample

Science.gov (United States)

Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Nief, J.-Y.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Padilla, C.; Park, I. C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Pacheco, A.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Rensch, B.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Teixeira-Dias, P.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Giehl, I.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Choi, Y.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Höcker, A.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Büscher, V.; Cowan, G.; Grupen, C.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, A. M.; Lan Wu, Sau; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

1996-02-01

The reaction e +e - → HZ ∗ is used to search for the standard model Higgs boson in the Hν overlineν and the Hℓ +ℓ - channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the H μ+μ- channel, in agreement with the expected background from the electroweak process e +e -ℓ +ℓ -q overlineq. This search results in a 95% C.L. lower limit on the Higgs boson mass of 63.9 GeV/ c2.

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.

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...

Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson ...

Indian Academy of Sciences (India)

The Higgs sector of the MSSM contains two scalar doublet fields leading to five ... At tree level, the masses and couplings of the MSSM Higgs bosons ..... J F Gunion, H E Haber, G Kane and S Dawson, The Higgs Hunters Guide (Addison-.

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.

CMS standard model Higgs boson results

Directory of Open Access Journals (Sweden)

Garcia-Abia Pablo

2013-11-01

Full Text Available In July 2012 CMS announced the discovery of a new boson with properties resembling those of the long-sought Higgs boson. The analysis of the proton-proton collision data recorded by the CMS detector at the LHC, corresponding to integrated luminosities of 5.1 fb−1 at √s = 7 TeV and 19.6 fb−1 at √s = 8 TeV, confirm the Higgs-like nature of the new boson, with a signal strength associated with vector bosons and fermions consistent with the expectations for a standard model (SM Higgs boson, and spin-parity clearly favouring the scalar nature of the new boson. In this note I review the updated results of the CMS experiment.

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.

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.

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....

Extended Higgs sectors in the context of supersymmetry at the LHC

Directory of Open Access Journals (Sweden)

Bandyopadhyay Priyotosh

2016-01-01

Full Text Available We study an extension of the Higgs sector of the Standard Model (SM with SU(2 triplet and a SM gauge singlet in the context of supersymmetry. For a Z3 symmetric superpotential where the singlet field generates the bilinear Higgs mixing term between the two Higgs doublets dynamically. Models like this, often have a very light pseudoscalar as a pseudo-Nambu Goldstone model of an extra U(1 symmetry. We investigate the possibility of such light hidden Higgs boson with the data of the discovered Higgs boson around 125 GeV. Along with the neutral sector, the charged Higgs bosons in the triplet extended case are really interesting. For instance, the triplet charged Higgs bosons give rise to new decay mode to ZW± along with an a1W± final state, due to the existence of a light pseudoscalar. These new modes can be looked for at the LHC in the search for Higgs bosons in other representations of SU(2.

Applying exclusion likelihoods from LHC searches to extended Higgs sectors

International Nuclear Information System (INIS)

Bechtle, Philip; Heinemeyer, Sven; Staal, Oscar; Stefaniak, Tim; Weiglein, Georg

2015-01-01

LHC searches for non-standard Higgs bosons decaying into tau lepton pairs constitute a sensitive experimental probe for physics beyond the Standard Model (BSM), such as supersymmetry (SUSY). Recently, the limits obtained from these searches have been presented by the CMS collaboration in a nearly model-independent fashion - as a narrow resonance model - based on the full 8 TeV dataset. In addition to publishing a 95 % C.L. exclusion limit, the full likelihood information for the narrowresonance model has been released. This provides valuable information that can be incorporated into global BSM fits. We present a simple algorithm that maps an arbitrary model with multiple neutral Higgs bosons onto the narrow resonance model and derives the corresponding value for the exclusion likelihood from the CMS search. This procedure has been implemented into the public computer code HiggsBounds (version 4.2.0 and higher). We validate our implementation by cross-checking against the official CMS exclusion contours in three Higgs benchmark scenarios in the Minimal Supersymmetric Standard Model (MSSM), and find very good agreement. Going beyond validation, we discuss the combined constraints of the ττ search and the rate measurements of the SM-like Higgs at 125 GeV in a recently proposed MSSM benchmark scenario, where the lightest Higgs boson obtains SM-like couplings independently of the decoupling of the heavier Higgs states. Technical details for how to access the likelihood information within HiggsBounds are given in the appendix. The program is available at http:// higgsbounds.hepforge.org. (orig.)

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

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.

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)

Can we distinguish an MSSM Higgs from a SM Higgs at a linear collider?

International Nuclear Information System (INIS)

Logan, Heather E.

2001-01-01

We study the prospects for distinguishing the CP-even Higgs boson of the minimal supersymmetric extension of the Standard Model (MSSM) from the Standard Model (SM) Higgs boson by measuring its branching ratios at an e + e - linear collider. The regions of the M A -tan β plane in which an MSSM Higgs boson can be distinguished from the SM Higgs boson depend strongly upon the supersymmetric parameters that enter the radiative corrections to the Higgs mass matrix and the Higgs couplings to fermions. In some regions of parameter space it is possible to extract the supersymmetric correction to the relation between the b quark mass and its Yukawa coupling from Higgs branching ratio measurements

{Delta}r in the Two-Higgs-Doublet Model at full one loop level - and beyond

Energy Technology Data Exchange (ETDEWEB)

Lopez-Val, David [Universitaet Heidelberg, Institut fuer Theoretische Physik, Heidelberg (Germany); Sola, Joan [Universitat de Barcelona, Dept. Estructura i Constituents de la Materia, Barcelona, Catalonia (Spain); Institut de Ciencies del Cosmos, Barcelona, Catalonia (Spain)

2013-04-15

After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The fundamental parameter {Delta}r, relating the values of the electroweak gauge boson masses and the Fermi constant, is the traditional observable encoding high precision information of the quantum effects. In this work we present a complete quantitative study of {Delta}r in the framework of the general Two-Higgs-Doublet Model (2HDM). While the one-loop analysis of {Delta}r in this model was carried out long ago, in the first part of our work we consistently incorporate the higher order effects that have been computed since then for the SM part of {Delta}r. Within the on-shell scheme, we find typical corrections leading to shifts of {proportional_to}20-40 MeV on the W mass, resulting in a better agreement with its experimentally measured value and in a degree no less significant than in the MSSM case. In the second part of our study we devise a set of effective couplings that capture the dominant higher order genuine 2HDM quantum effects on the {delta}{rho} part of {Delta}r in the limit of large Higgs boson self-interactions. This limit constitutes a telltale property of the general 2HDM which is unmatched by e.g. the MSSM. (orig.)

Δr in the Two-Higgs-Doublet Model at full one loop level - and beyond

International Nuclear Information System (INIS)

Lopez-Val, David; Sola, Joan

2013-01-01

After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The fundamental parameter Δr, relating the values of the electroweak gauge boson masses and the Fermi constant, is the traditional observable encoding high precision information of the quantum effects. In this work we present a complete quantitative study of Δr in the framework of the general Two-Higgs-Doublet Model (2HDM). While the one-loop analysis of Δr in this model was carried out long ago, in the first part of our work we consistently incorporate the higher order effects that have been computed since then for the SM part of Δr. Within the on-shell scheme, we find typical corrections leading to shifts of ∝20-40 MeV on the W mass, resulting in a better agreement with its experimentally measured value and in a degree no less significant than in the MSSM case. In the second part of our study we devise a set of effective couplings that capture the dominant higher order genuine 2HDM quantum effects on the δρ part of Δr in the limit of large Higgs boson self-interactions. This limit constitutes a telltale property of the general 2HDM which is unmatched by e.g. the MSSM. (orig.)

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...

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

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.

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.

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.

Swimming against the tide: explaining the Higgs

CERN Multimedia

Emma Sanders

2012-01-01

"Never before in the field of science journalism have so few journalists understood what so many physicists were telling them!" tweeted the UK Channel 4’s Tom Clarke from last December’s Higgs seminar. As a consequence, most coverage focused on debates over the use of the label “god particle” and the level of excitement of the physicists (high), whilst glossing over what this excitement was actually all about.   So what is the Higgs? Something fundamental. Something to do with mass. If your interest in physics is more than simply passing, you may find that rooms full of chattering politicians or the use of different footwear when walking through snow just don’t do the job in convincing you why the Higgs is so important. And if images of fish make you feel like a fish out of water - or at least one swimming against a strong current - then perhaps you would appreciate a different approach. The need for the Higgs Whilst gauge th...

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.

W/Top/Higgs-tagging in ATLAS

CERN Document Server

Norjoharuddeen, Nurfikri; The ATLAS collaboration

2017-01-01

We present updates of W, Top and Higgs tagging studies with the ATLAS detector. The performance of 2 variable taggers, HEPTopTagger and shower deconstruction are compared in Monte Carlo simulations. To asses the modelling of the taggers’ performance, the tagging efficiencies are measured, with the full 2015+2016 dataset, in semi-leptonic top quark pair events and the background rejections are measured in dijet and photon+jet topologies. Recent developments in subjet reconstruction techniques for high transverse momentum Higgs->bb tagging are also presented.

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.

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.

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...

Higgs boson production and decay at e+e− colliders as a probe of the Left–Right twin Higgs model

Directory of Open Access Journals (Sweden)

Jinzhong Han

2015-07-01

Full Text Available In the framework of the Left–Right twin Higgs (LRTH model, we consider the constrains from the latest search for high-mass dilepton resonances at the LHC and find that the heavy neutral boson ZH is excluded with mass below 2.76 TeV. Under these constrains, we study the Higgs–Gauge coupling production processes e+e−→ZH, e+e−→νeνe¯H and e+e−→e+e−H, top quark Yukawa coupling production process e+e−→tt¯H, Higgs self-couplings production processes e+e−→ZHH and e+e−→νeνe¯HH at e+e− colliders. Besides, we study the major decay modes of the Higgs boson, namely h→ff¯(f=b,c,τ, VV⁎(V=W,Z, gg, γγ. We find that the LRTH effects are sizable so that the Higgs boson processes at e+e− collider can be a sensitive probe for the LRTH model.

Fingerprinting the extended Higgs sector using one-loop corrected Higgs boson couplings and future precision measurements

Directory of Open Access Journals (Sweden)

Shinya Kanemura

2015-07-01

Full Text Available We calculate radiative corrections to a full set of coupling constants for the 125 GeV Higgs boson at the one-loop level in two Higgs doublet models with four types of Yukawa interaction under the softly-broken discrete Z2 symmetry. The renormalization calculations are performed in the on-shell scheme, in which the gauge dependence in the mixing parameter which appears in the previous calculation is consistently avoided. We first show the details of our renormalization scheme, and present the complete set of the analytic formulae of the renormalized couplings. We then numerically demonstrate how the inner parameters of the model can be extracted by the future precision measurements of these couplings at the high luminosity LHC and the International Linear Collider.

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.

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).

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.

Higgs naturalness and dark matter stability by scale invariance

Directory of Open Access Journals (Sweden)

Jun Guo

2015-09-01

Full Text Available Extending the spacetime symmetries of standard model (SM by scale invariance (SI may address the Higgs naturalness problem. In this article we attempt to embed accidental dark matter (DM into SISM, requiring that the symmetry protecting DM stability is accidental due to the model structure rather than imposed by hand. In this framework, if the light SM-like Higgs boson is the pseudo Goldstone boson of SI spontaneously breaking, we can even pine down the model, two-Higgs-doublets plus a real singlet: The singlet is the DM candidate and the extra Higgs doublet triggers electroweak symmetry breaking via the Coleman–Weinberg mechanism; Moreover, it dominates DM dynamics. We study spontaneously breaking of SI using the Gillard–Weinberg approach and find that the second doublet should acquire vacuum expectation value near the weak scale. Moreover, its components should acquire masses around 380 GeV except for a light CP-odd Higgs boson. Based on these features, we explore viable ways to achieve the correct relic density of DM, facing stringent constraints from direct detections of DM. For instance, DM annihilates into bb¯ near the SM-like Higgs boson pole, or into a pair of CP-odd Higgs boson with mass above that pole.

Higgs Boson Pair Production in Gluon Fusion at Next-to-Leading Order with Full Top-Quark Mass Dependence.

Science.gov (United States)

Borowka, S; Greiner, N; Heinrich, G; Jones, S P; Kerner, M; Schlenk, J; Schubert, U; Zirke, T

2016-07-01

We present the calculation of the cross section and invariant mass distribution for Higgs boson pair production in gluon fusion at next-to-leading order (NLO) in QCD. Top-quark masses are fully taken into account throughout the calculation. The virtual two-loop amplitude has been generated using an extension of the program GoSam supplemented with an interface to Reduze for the integral reduction. The occurring integrals have been calculated numerically using the program SecDec. Our results, including the full top-quark mass dependence for the first time, allow us to assess the validity of various approximations proposed in the literature, which we also recalculate. We find substantial deviations between the NLO result and the different approximations, which emphasizes the importance of including the full top-quark mass dependence at NLO.

Composite Higgs under LHC Experimental Scrutiny

Directory of Open Access Journals (Sweden)

Mühlleitner M.

2012-06-01

Full Text Available The LHC has been built to understand the dynamics at the origin of the breaking of the electroweak symmetry. Weakly coupled models with a fundamental Higgs boson have focused most of the attention of the experimental searches. We will discuss here how to reinterpret these searches in the context of strongly coupled models where the Higgs boson emerges as a composite particle. In particular, we use LHC data to constrain the compositeness scale. We also briefly review the prospects to observe other bosonic and fermionic resonances of the strong sector.

Effect of multiple Higgs fields on the phase structure of the SU(2)-Higgs model

International Nuclear Information System (INIS)

Wurtz, Mark; Steele, T. G.; Lewis, Randy

2009-01-01

The SU(2)-Higgs model, with a single Higgs field in the fundamental representation and a quartic self-interaction, has a Higgs region and a confinement region which are analytically connected in the parameter space of the theory; these regions thus represent a single phase. The effect of multiple Higgs fields on this phase structure is examined via Monte Carlo lattice simulations. For the case of N≥2 identical Higgs fields, there is no remaining analytic connection between the Higgs and confinement regions, at least when Lagrangian terms that directly couple different Higgs flavors are omitted. An explanation of this result in terms of enhancement from overlapping phase transitions is explored for N=2 by introducing an asymmetry in the hopping parameters of the Higgs fields. It is found that an enhancement of the phase transitions can still occur for a moderate (10%) asymmetry in the resulting hopping parameters.

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.

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.)

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.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set.

Science.gov (United States)

Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; 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; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

2015-04-10

A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^{P}=0^{-} and a gravitonlike Higgs boson with J^{P}=2^{+}, assuming for both a mass of 125  GeV/c^{2}. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of sqrt[s]=1.96  TeV, and correspond to an integrated luminosity of 9.45  fb^{-1}. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125  GeV/c^{2} at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set

Energy Technology Data Exchange (ETDEWEB)

Aaltonen, Timo Antero [Univ. of Helsinki, Helsinki (Finland); Helsinki Institute of Physics, Helsinki (Finland). et al.

2015-04-10

In this study, a search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^P = 0^– and a gravitonlike Higgs boson with J^P = 2⁺, assuming for both a mass of 125 GeV/c². We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of √s = 1.96 TeV, and correspond to an integrated luminosity of 9.45 fb^–1. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125 GeV/c² at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Higher order corrections to Higgs boson decays in the MSSM with complex parameters

Energy Technology Data Exchange (ETDEWEB)

Williams, Karina E. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Rzehak, Heidi [Freiburg Univ. (Germany). Physikalisches Inst.; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2011-03-15

We discuss Higgs boson decays in the CP-violating MSSM, and examine their phe- nomenological impact using cross section limits from the LEP Higgs searches. This includes a discussion of the full 1-loop results for the partial decay widths of neutral Higgs bosons into lighter neutral Higgs bosons (h{sub a}{yields}h{sub b}h{sub c}) and of neutral Higgs bosons into fermions (h{sub a}{yields}f anti f). In calculating the genuine vertex corrections, we take into account the full spectrum of supersymmetric particles and all complex phases of the supersymmetric parameters. These genuine vertex corrections are supplemented with Higgs propagator corrections incorporating the full one-loop and the dominant two-loop contributions, and we illustrate a method of consistently treating diagrams involving mixing with Goldstone and Z bosons. In particular, the genuine vertex corrections to the process h{sub a}{yields}h{sub b}h{sub c} are found to be very large and, where this process is kinematically allowed, can have a significant effect on the regions of the CPX bench- mark scenario which can be excluded by the results of the Higgs searches at LEP. However, there remains an unexcluded region of CPX parameter space at a lightest neutral Higgs boson mass of {proportional_to}45 GeV. In the analysis, we pay particular attention to the conversion between parameters defined in different renormalisation schemes and are therefore able to make a comparison to the results found using renormalisation group improved/effective potential calculations. (orig.)

Higgs instability and de Sitter radiation

Directory of Open Access Journals (Sweden)

Gaurav Goswami

2015-12-01

Full Text Available If the Standard Model (SM of elementary particle physics is assumed to hold good to arbitrarily high energies, then, for the best fit values of the parameters, the scalar potential of the Standard Model Higgs field turns negative at a high scale μinst. If the physics beyond the SM is such that it does not modify this feature of the Higgs potential and if the Hubble parameter during inflation (Hinf is such that Hinf≫μinst, then, quantum fluctuations of the SM Higgs during inflation make it extremely unlikely that after inflation it will be found in the metastable vacuum at the weak scale. In this work, we assume that (i during inflation, the SM Higgs is in Bunch–Davies vacuum state, and, (ii the question about the stability of the effective potential must be answered in the frame of the freely falling observer (just like in Minkowski spacetime, and then use the well-known fact that the freely falling observer finds Bunch–Davies vacuum to be in thermal state to show that the probability to end up in the electroweak vacuum after inflation is reasonably high.

Two Higgs Doublet Model and Model Independent Interpretation of Neutral Higgs Boson Searches

CERN Document Server

Abbiendi, G.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, John; Anderson, K.J.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Bailey, I.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Baumann, S.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Benelli, G.; Bentvelsen, S.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; de Roeck, A.; de Wolf, E.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanti, M.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Glenzinski, D.; Goldberg, J.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Stoll, K.; Strom, David M.; Strohmer, R.; Stumpf, L.; Surrow, B.; Talbot, S.D.; Tarem, S.; Taylor, R.J.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Vachon, B.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

2001-01-01

Searches for the neutral Higgs bosons h0 and A0, are used to obtain limits on the Type II Two Higgs Doublet Model (2HDM(II)) with no CP-violation in the Higgs sector and no additional particles besides the five Higgs bosons. The analysis combines approximately 170 pb-1 of data collected with the OPAL detector at sqrt{s} ~ 189 GeV with previous runs at sqrt{s} ~ mZ and sqrt{s} ~ 183 GeV. The searches are sensitive to the h0, A0 -> qq, gg, tau+tau- and h0 -> A0A0 decay modes of the Higgs bosons. For the first time, the 2HDM(II) parameter space is explored in a detailed scan, and new flavour independent analyses are applied to examine regions in which the neutral Higgs bosons decay predominantly into light quarks or gluons. Model-independent limits are also given.

THE HIGGS WORKING GROUP: SUMMARY REPORT.

Energy Technology Data Exchange (ETDEWEB)

DAWSON, S.; ET AL.

2005-08-01

This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e{sup +}e{sup -} collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg {yields} H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan {beta} and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e{sup +}e{sup -} collider.

THE HIGGS WORKING GROUP: SUMMARY REPORT

International Nuclear Information System (INIS)

DAWSON, S.

2005-01-01

This working group has investigated Higgs boson searches at the Tevatron and the LHC. Once Higgs bosons are found their properties have to be determined. The prospects of Higgs coupling measurements at the LHC and a high-energy linear e + e - collider are discussed in detail within the Standard Model and its minimal supersymmetric extension (MSSM). Recent improvements in the theoretical knowledge of the signal and background processes are presented and taken into account. The residual uncertainties are analyzed in detail. Theoretical progress is discussed in particular for the gluon-fusion processes gg → H(+j), Higgs-bremsstrahlung off bottom quarks and the weak vector-boson-fusion (VBF) processes. Following the list of open questions of the last Les Houches workshop in 2001 several background processes have been calculated at next-to-leading order, resulting in a significant reduction of the theoretical uncertainties. Further improvements have been achieved for the Higgs sectors of the MSSM and NMSSM. This report summarizes our work performed before and after the workshop in Les Houches. Part A describes the theoretical developments for signal and background processes. Part B presents recent progress in Higgs boson searches at the Tevatron collider. Part C addresses the determination of Higgs boson couplings, part D the measurement of tan β and part E Higgs boson searches in the VBF processes at the LHC. Part F summarizes Higgs searches in supersymmetric Higgs decays, part G photonic Higgs decays in Higgs-strahlung processes at the LHC, while part H concentrates on MSSM Higgs bosons in the intense-coupling regime at the LHC. Part I presents progress in charged Higgs studies and part J the Higgs discovery potential in the NMSSM at the LHC. The last part K describes Higgs coupling measurements at a 1 TeV linear e + e - collider

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.

New ATLAS Higgs physics results

CERN Multimedia

CERN. Geneva

2014-01-01

New Higgs physics results from the ATLAS experiment using the full Run-1 LHC dataset, corresponding to an integrated luminosity of approximately 25 fb-1, of proton-proton collisions at 7 TeV and 8 TeV, will be presented.

Higher-order corrected Higgs bosons in FeynHiggs2.4

Indian Academy of Sciences (India)

treatment of loop-corrected Higgs-boson mass eigenstates as external (on-shell) or internal .... This gives rise to finite wave function normalization factors. [22]. .... The elements of Un can be interpreted as effective couplings of internal Higgs.

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.

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.

Search for the Higgs boson in fermionic channels using the ATLAS detector

Directory of Open Access Journals (Sweden)

Hageböck Stephan

2015-01-01

Full Text Available Since the discovery of the Higgs boson by the ATLAS and CMS experiments at the LHC, the emphasis has shifted towards measurements of its properties. Of particular importance is the direct observation of the coupling of the Higgs boson to fermions. A review of ATLAS results in the search for the Higgs boson in tau, muon and b-quark pairs is presented.

SM-like Higgs decay into two muons at 1.4 TeV CLIC

CERN Document Server

Milutinovic-Dumbelovic, G

2014-01-01

The potential for measuring the Standard Model (SM) Higgs boson decay into two muons at a 1.4 TeV CLIC e+e− collider is addressed in this paper, that was presented at ICHEP2014. The study is performed in the full Geant4 detector simulations of CLIC_ILD, taking into consideration all the relevant physics and the beam-induced background processes, as well as the instrumentation of the very forward region to tag forward electrons. In this analysis we show that the branching ratio BR(H-->mu+mu-) times the Higgs production cross-section can be measured with 38% statistical accuracy at √s =1.4 TeV using an integrated luminosity of 1.5 ab-1. This study is part of an ongoing comprehensive Higgs physics benchmark study covering various Higgs production processes and decay modes, currently being carried out to estimate the full Higgs physics potential of CLIC.

Low-Data Investigation of Higgs Boson Discovery at the LHC

CERN Document Server

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, but cannot give a precise value to its mass. Experiment and theoretical arguments have put limits on the Higgs mass to within 114.7 GeV/c2 < MH < 1000 GeV/c2. The Large Hadron Collider at CERN will provide access to a new energy regime that will offer many channels for a potential discovery of the Higgs. In the Compact Muon Solenoid (CMS) detector experiment, the “Golden mode” for Higgs discovery features decay to two Z0, with both Z0 decaying to leptonic final states. Full reconstruction analyses suffer from the...

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 ...

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.

Interference contributions to gluon initiated heavy Higgs production in the Two-Higgs-Doublet Model

International Nuclear Information System (INIS)

Greiner, Nicolas

2016-03-01

We discuss the production of a heavy neutral Higgs boson of a CP-conserving Two-Higgs-Doublet Model in gluon fusion and its decay into a four-fermion final state, gg(→VV)→e + e - π + π - /e + e - ν l anti ν l . We investigate the interference contributions to invariant mass distributions of the four-fermion final state and other relevant kinematical observables. The relative importance of the different contributions is quantified for the process in the on-shell approximation, gg→ZZ. We show that interferences of the heavy Higgs with the light Higgs boson and background contributions are essential for a correct description of the differential cross section. Even though they contribute below O(10%) to those heavy Higgs signal cross sections, to which the experiments at the Large Hadron Collider were sensitive in its first run, we find that they are sizeable in certain regions of the parameter space that are relevant for future heavy Higgs boson searches. In fact, the interference contributions can significantly enhance the experimental sensitivity to the heavy Higgs boson.

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.

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

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.

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.

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'.

Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa Model

Energy Technology Data Exchange (ETDEWEB)

Gerhold, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany); Jansen, K. [John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany)

2010-02-15

We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the Higgs-fermion sector of the Standard Model. As expected from the triviality picture of the Higgs sector, we observe the upper mass bound to decrease with rising cutoff parameter {lambda}. Moreover, the strength of the fermionic contribution to the upper mass bound is explored by comparing to the corresponding analysis in the pure {phi}{sup 4}-theory. (orig.)

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...

The Higgs boson resonance from a chiral Higgs-Yukawa model on the lattice

Energy Technology Data Exchange (ETDEWEB)

Kallarackal, Jim

2011-04-28

Despite the fact that the standard model of particle physics has been confirmed in many high energy experiments, the existence of the Higgs boson is not assured. The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for fermions and the weak gauge bosons. The goal of this work is to set limits on the mass and the decay width of the Higgs boson. The basis to compute the physical quantities is the path integral which is here evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. A polynomial hybrid Monte Carlo algorithm is used to incorporate dynamical fermions. The chiral symmetry of the electroweak model is incorporated by using the Neuberger overlap operator. Here, the standard model is considered in the limit of a Higgs-Yukawa sector which does not contain the weak gauge bosons and only a degenerate doublet of top- and bottom quarks are incorporated. Results from lattice perturbation theory up to one loop of the Higgs boson propagator are compared with those obtained from Monte Carlo simulations at three different values of the Yukawa coupling. At all values of the investigated couplings, the perturbative results agree very well with the Monte Carlo data. A main focus of this work is the investigation of the resonance parameters of the Higgs boson. The resonance width and the resonance mass are investigated at weak and at large quartic couplings. The parameters of the model are chosen such that the Higgs boson can decay into any even number of Goldstone bosons. Thus, the Higgs boson does not appear as an asymptotic stable state but as a resonance. In all considered cases the Higgs boson resonance width lies below 10% of the resonance mass. The obtained resonance mass is compared with the mass obtained from the Higgs boson propagator. The results agree perfectly at all values of the quartic coupling considered. Finally, the effect of a heavy fourth generation of fermions on the

The Higgs boson resonance from a chiral Higgs-Yukawa model on the lattice

International Nuclear Information System (INIS)

Kallarackal, Jim

2011-01-01

Despite the fact that the standard model of particle physics has been confirmed in many high energy experiments, the existence of the Higgs boson is not assured. The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for fermions and the weak gauge bosons. The goal of this work is to set limits on the mass and the decay width of the Higgs boson. The basis to compute the physical quantities is the path integral which is here evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. A polynomial hybrid Monte Carlo algorithm is used to incorporate dynamical fermions. The chiral symmetry of the electroweak model is incorporated by using the Neuberger overlap operator. Here, the standard model is considered in the limit of a Higgs-Yukawa sector which does not contain the weak gauge bosons and only a degenerate doublet of top- and bottom quarks are incorporated. Results from lattice perturbation theory up to one loop of the Higgs boson propagator are compared with those obtained from Monte Carlo simulations at three different values of the Yukawa coupling. At all values of the investigated couplings, the perturbative results agree very well with the Monte Carlo data. A main focus of this work is the investigation of the resonance parameters of the Higgs boson. The resonance width and the resonance mass are investigated at weak and at large quartic couplings. The parameters of the model are chosen such that the Higgs boson can decay into any even number of Goldstone bosons. Thus, the Higgs boson does not appear as an asymptotic stable state but as a resonance. In all considered cases the Higgs boson resonance width lies below 10% of the resonance mass. The obtained resonance mass is compared with the mass obtained from the Higgs boson propagator. The results agree perfectly at all values of the quartic coupling considered. Finally, the effect of a heavy fourth generation of fermions on the

The ATLAS Higgs Machine Learning Challenge

CERN Document Server

Cowan, Glen; The ATLAS collaboration; Bourdarios, Claire

2015-01-01

High Energy Physics has been using Machine Learning techniques (commonly known as Multivariate Analysis) since the 1990s with Artificial Neural Net and more recently with Boosted Decision Trees, Random Forest etc. Meanwhile, Machine Learning has become a full blown field of computer science. With the emergence of Big Data, data scientists are developing new Machine Learning algorithms to extract meaning from large heterogeneous data. HEP has exciting and difficult problems like the extraction of the Higgs boson signal, and at the same time data scientists have advanced algorithms: the goal of the HiggsML project was to bring the two together by a “challenge”: participants from all over the world and any scientific background could compete online to obtain the best Higgs to tau tau signal significance on a set of ATLAS fully simulated Monte Carlo signal and background. Instead of HEP physicists browsing through machine learning papers and trying to infer which new algorithms might be useful for HEP, then c...

Higgs Boson fermionic production and decay modes with the ATLAS detector

CERN Document Server

Piacquadio, Giacinto; The ATLAS collaboration

2018-01-01

The Higgs couplings to heavy quarks, top and bottom quarks, are difficult to directly access experimentally, nevertheless their measurement is crucial for a full characterization of the Higgs sector and to probe a large variety of physics scenarios beyond the Standard Model. In this talk I will discuss the results recently obtained by the ATLAS Collaboration based on Run-2 2015 and 2016 data, which led to evidence for Higgs boson decays to b-quarks and for the ttH production mode.

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.

ISR corrections to associated HZ production at future Higgs factories

Directory of Open Access Journals (Sweden)

Mario Greco

2018-02-01

Full Text Available We evaluate the QED corrections due to initial state radiation (ISR to associated Higgs boson production in electron–positron (e+e− annihilation at typical energies of interest for the measurement of the Higgs properties at future e+e− colliders, such as CEPC and FCC–ee. We apply the QED Structure Function approach to the four-fermion production process e+e−→μ+μ−bb¯, including both signal and background contributions. We emphasize the relevance of the ISR corrections particularly near threshold and show that finite third order collinear contributions are mandatory to meet the expected experimental accuracy. We analyze in turn the rôle played by a full four-fermion calculation and beam energy spread in precision calculations for Higgs physics at future e+e− colliders.

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.)

Electroweak symmetry breaking: Higgs/whatever

International Nuclear Information System (INIS)

Chanowitz, M.S.

1990-01-01

In these two lectures the author discusses electroweak symmetry breaking from a general perspective, stressing properties that are model independent and follow just from the assumption that the electroweak interactions are described by a spontaneously broken gauge theory. This means he assumes the Higgs mechanism though not necessarily the existence of Higgs bosons. The first lecture presents the general framework of a spontaneously broken gauge theory: (1) the Higgs mechanism sui generis, with or without Higgs boson(s) and (2) the implications of symmetry and unitarity for the mass scale and interaction strength of the new physics that the Higgs mechanism requires. In addition he reviews a softer theoretical argument based on the naturalness problem which leads to a prejudice against Higgs bosons unless they are supersymmetric. This is a prejudice, not a theorem, and it could be overturned in the future by a clever new idea. In the second lecture he illustrates the general framework by reviewing some specific models: (1) the Weinberg-Salam model of the Higgs sector; (2) the minimal supersymmetric extension of the Weinberg-Salam model; and (3) technicolor as an example of the Higgs mechanism without Higgs bosons. He concludes the second lecture with a discussion of strong WW scattering that must occur if L SB lives above 1 TeV. In particular he describes some of the experimental signals and backgrounds at the SSC. 57 refs., 12 figs

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.

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...

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.

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.

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

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).

ISR effects for resonant Higgs production at future lepton colliders

Directory of Open Access Journals (Sweden)

Mario Greco

2016-12-01

Full Text Available We study the effects of the initial state radiation on the s-channel Higgs boson resonant production at μ+μ− and e+e− colliders by convoluting with the beam energy spread profile of the collider and the Breit–Wigner resonance profile of the signal. We assess their impact on both the Higgs signal and SM backgrounds for the leading decay channels h→bb¯, WW⁎. Our study improves the existing analyses of the proposed future resonant Higgs factories and provides further guidance for the accelerator designs with respect to the physical goals.

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...

Beyond the standard Higgs after the 125 GeV Higgs discovery.

Science.gov (United States)

Grojean, C

2015-01-13

An elementary weakly coupled and solitary Higgs boson allows one to extend the validity of the Standard Model up to very high energy, maybe as high as the Planck scale. Nonetheless, this scenario fails to fill the universe with dark matter and does not explain the matter-antimatter asymmetry. However, amending the Standard Model tends to destabilize the weak scale by large quantum corrections to the Higgs potential. New degrees of freedom, new forces, new organizing principles are required to provide a consistent and natural description of physics beyond the standard Higgs.

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)

A new implementation of the NMSSM Higgs boson decays

Directory of Open Access Journals (Sweden)

Spira M.

2013-05-01

Full Text Available Supersymmetric theories provide elegant extensions of the Standard Model. Among these the NMSSM is a model which in addition to the content of the MSSM includes a new singlet to solve the μ problem. We present here the basic features of the NMSSM Higgs sector and a new Fortran implementation of the decays of the Higgs bosons in the NMSSM, both with real and complex parameters.

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.

Are Higgs particles strongly interacting(question mark)

International Nuclear Information System (INIS)

Shanker, O.

1982-02-01

The order of magnitude of Yukawa couplings in some theories with flavour violating Higgs particles is estimated. Based on these couplings, mass bounds for flavour violating Higgs particles are derived from the Ksub(L)-Ksub(S) mass difference. The Higgs particles have to be very heavy, implying that the Higgs sector quartic couplings are very large. Thus, these theories seem to require a strongly interacting Higgs sector unless one adjusts to the Higgs-fermion Yukawa couplings to within two orders of magnitude, so as to suppress the coupling of Higgs particles to the flavour-violating anti sd current. Most models with flavour violating Higgs particles have the same general features, so the conclusions are likely to hold for a wide class of models with flavour violating Higgs particles

CMS latest results on Higgs measurements

CERN Multimedia

CERN. Geneva

2014-01-01

Since the discovery of a Higgs boson by the CMS and ATLAS Collaborations in 2012, physicists at the LHC have been making intense efforts to measure this new particle’s properties. Last week, at the 37th International Conference on High Energy Physics, the CMS Collaboration has presented a broad set of results from new studies of the Higgs boson. They are based on the full Run 1 data from pp collisions at centre-of-mass energies of 7 and 8 TeV. The analyses include the final calibration and alignment constants and contains about 25 fb−1 of data. These new results will be summarized here.

Radiative generation of the Higgs potential

International Nuclear Information System (INIS)

Chun, Eung Jin; Jung, Sunghoon; Lee, Hyun Min

2013-01-01

We consider the minimal extension of the Standard Model with U(1) B−L gauge symmetry for generating the Higgs potential radiatively. Assuming that the full scalar potential vanishes at the vacuum instability scale, we achieve the goal in terms of two free parameters, the B−L gauge coupling and the right-handed neutrino Yukawa coupling. The B−L gauge symmetry is broken spontaneously by the Coleman–Weinberg mechanism while the scale symmetry breakdown induces electroweak symmetry breaking through the radiative generation of appropriate scalar quartic couplings. We show that there is a reasonable parameter space that is consistent with a correct electroweak symmetry breaking and the observed Higgs mass

Toponium and two-Higgs models

International Nuclear Information System (INIS)

Franzini, P.J.

1986-04-01

Bounds from B 0 - anti B 0 mixing on charged-Higgs-boson masses and couplings in two-Higgs-doublet models are presented. These bounds are comparable to those obtained, with additional assumptions, from the neutral-K-system. The effects of the neutral Higgs bosons of these models on the spectrum and wave function of toponium are discussed. These effects could, in the future, lead to limits on, or the discovery of, these Higgs bosons. 8 refs., 3 figs

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.

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.

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.)

Measuring the Higgs self-coupling at the International Linear Collider

International Nuclear Information System (INIS)

Duerig, Claude Fabienne

2016-10-01

In this thesis, the experimental prospects of measuring the Standard Model (SM) Higgs self-coupling λ_S_M at the International Linear Collider (ILC) are investigated. The observation of double Higgs production is necessary to directly establish a non-zero Higgs self-coupling. Information on λ_S_M can be extracted from a measurement of the cross section for this process. At a centre-of-mass energy of √(s)=500 GeV double Higgs-strahlung is the dominant Higgs-pair production process. This measurement is extremely challenging due to very small production cross sections and multi-jet final states which pose large challenges to detector technologies and event reconstruction techniques. A detailed full detector simulation of the International Large Detector is performed for a Higgs boson with a mass of 125 GeV. The analysis is based on ILC beam parameters according to the Technical Design Report and investigates several improvements compared to earlier studies. These include an isolated lepton selection strategy and the application of kinematic fits to final states with heavy-flavoured jets. Depending on the decay mode of the Z boson, relative improvements of up to 25% are obtained in the selection of ZHH (HH → bbbb) events. This results in a relative improvement of 10% in the measurement of σ_Z_H_H when combining all channels. For the SM scenario, an evidence of 3.5σ for the observation of double Higgs-strahlung and a measurement precision of 30% on σ_Z_H_H is reached with an integrated luminosity of L=2ab"-"1 and a beam polarisation of P(e"+e"-)=(0.3,-0.8). The result extrapolates to an achievable precision of 21% on σ_Z_H_H after the full ILC running scenario, which corresponds to a 5.9σ discovery for the observation of double Higgs-strahlung. Combined with the channel HH→bbWW, σ_Z_H_H can even be measured to a precision of 16%, which corresponds to a precision of 26% on λ_S_M. Additionally, the impact of γγ→low-p_T hadrons background is investigated

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)

Higgs Boson in Multi-b-Jets Final States Reconstruction with Full Simulation of Atlas Detector

International Nuclear Information System (INIS)

Sapinski, M.; Cavalli, D.

2001-01-01

Channels with multi-b-jet final states are very important in the discovery strategies for the Higgs boson search in ATLAS experiment at LHC. Excellent jets reconstruction efficiencies and mass resolution capability of the di-jet system are crucial aspects of the detector performance for the signal observability in these channels. Full simulation and reconstruction of the four representative channels with b-jets in final states is discussed: WH, t(anti)tH with H → b(anti)b and A → Zh, H → hh with h → b(anti)b. These channels are used as benchmark ones to study the different complexity of events, level of combinatorial background from signal itself and universality of the algorithms used for jets reconstruction and energy calibration at the wide range of energy/mass scales. Equivalently important aspect of this study is to verify applicability of the fast detector simulation, based on parametrisation of main features of the detector, for studying signal and background rates for the above channels. For that reason the detailed comparisons of the expected efficiencies and acceptances in full (based on GEANT 3) and fast simulations are shown at the different stages of the selection procedures. In general good agreement is found between results obtained in both approaches. (author)

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)

A Correlation between the Higgs Mass and Dark Matter

Directory of Open Access Journals (Sweden)

Mark P. Hertzberg

2017-01-01

Full Text Available Depending on the value of the Higgs mass, the Standard Model acquires an unstable region at large Higgs field values due to RG running of couplings, which we evaluate at 2-loop order. For currently favored values of the Higgs mass, this renders the electroweak vacuum only metastable with a long lifetime. We argue on statistical grounds that the Higgs field would be highly unlikely to begin in the small field metastable region in the early universe, and thus some new physics should enter in the energy range of order of, or lower than, the instability scale to remove the large field unstable region. We assume that Peccei-Quinn (PQ dynamics enters to solve the strong CP problem and, for a PQ-scale in this energy range, may also remove the unstable region. We allow the PQ-scale to scan and argue, again on statistical grounds, that its value in our universe should be of order of the instability scale, rather than (significantly lower. Since the Higgs mass determines the instability scale, which is argued to set the PQ-scale, and since the PQ-scale determines the axion properties, including its dark matter abundance, we are led to a correlation between the Higgs mass and the abundance of dark matter. We find the correlation to be in good agreement with current data.

Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely charged leptons using the full CDF data set.

Science.gov (United States)

Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M E; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calamba, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; 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; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chung, W H; Chung, Y S; Ciocci, M A; Clark, A; Clarke, C; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; Dell'Orso, M; Demortier, L; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, S; Ershaidat, N; Eusebi, R; Farrington, S; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeans, D T; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kim, Y J; Kimura, N; Kirby, M; Klimenko, S; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; LeCompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Mastrandrea, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Prokoshin, F; Pranko, A; Ptohos, F; Punzi, G; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Sorin, V; Song, H; Squillacioti, P; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Tipton, P; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; 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; Zanetti, A; Zeng, Y; Zhou, C; Zucchelli, S

2012-09-14

We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45  fb(-1). In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H→bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125  GeV/c(2), we observe (expect) a limit of 7.1 (3.9) times the standard model value.

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

Higgs friends and counterfeits at hadron colliders

International Nuclear Information System (INIS)

Fox, Patrick J.; Tucker-Smith, David; Weiner, Neal

2011-01-01

We consider the possibility of 'Higgs counterfeits' - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving 'Higgs friends,' fields similarly produced through gg fusion processes, which would be discovered through diboson channels WW,ZZ,γγ, or even γZ, potentially with larger cross sections times branching ratios than for the Higgs. The discovery of either a Higgs friend or a Higgs counterfeit, rather than directly pointing towards the origin of the weak scale, would indicate the presence of new colored fields necessary for the sizable production cross section (and possibly new colorless but electroweakly charged states as well, in the case of the diboson decays of a Higgs friend). These particles could easily be confused for an ordinary Higgs, perhaps with an additional generation to explain the different cross section, and we emphasize the importance of vector boson fusion as a channel to distinguish a Higgs counterfeit from a true Higgs. Such fields would naturally be expected in scenarios with 'effective Z's,' where heavy states charged under the SM produce effective charges for SM fields under a new gauge force. We discuss the prospects for discovery of Higgs counterfeits, Higgs friends, and associated charged fields at the LHC.

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.)

BSM Higgs results from ATLAS and CMS

Directory of Open Access Journals (Sweden)

Flechl Martin

2013-11-01

Full Text Available Résumé. Searches for Higgs bosons in different extensions of the Standard Model (SM are presented. These include the Minimal Supersymmetric extension of the SM (MSSM, the next-to-MSSM (NMSSM, models with additional scalar singlets, doublets, or triplets, and generic searches for models with couplings modified with respect to the SM or for non-SM Higgs boson decay channels. Results are based on data collected by the ATLAS and CMS experiments in 2011 and 2012 at the LHC. No excess is found in any of the searches and thus the resulting exclusion limits are given.

Gauge boson/Higgs boson unification: The Higgs bosons as superpartners of massive gauge bosons

International Nuclear Information System (INIS)

Fayet, P.

1984-01-01

We show how one can use massive gauge superfields to describe, simultaneously, gauge bosons (Wsup(+-), Z, ...) and Higgs bosons (wsup(+-), z, ...) together with their spin-1/2 partners (pairs of winos, zinos, ...), despite their different electroweak properties. This provides a manifestly supersymmetric formulation of spontaneously broken supersymmetric gauge theories, and makes explicit the relations between massive gauge bosons and Higgs bosons. It raises, however, the following question: if the gauge bosons Wsup(+-) and Z and the Higgs bosons wsup(+-) and z are related by supersymmetry, how it is possible that the former couple to leptons and quarks proportionately to g or g', and the latter proportionately to gsub(F)sup(1/2) m (fermions). The paradox is solved as follows: when the Higgs bosons are described by massive gauge superfields, the lagrangian density is non-polynomial and field redefinitions have to be performed, in particular: lepton or quark field -> lepton or quark field + (approx.= Gsub(F)sup(1/2) Higgs field) (lepton or quark field). They automatically regenerate, from the lepton and quark supersymmetric mass terms, the correct Yukawa couplings of Higgs bosons proportional to fermion masses. We also apply this method to the case in which an extra U(1) group is gauged, the standard Higgs boson h 0 being then the superpartner of the new neutral gauge boson U. (orig.)

Model-independent determination of the triple Higgs coupling at e+e- colliders

Science.gov (United States)

Barklow, Tim; Fujii, Keisuke; Jung, Sunghoon; Peskin, Michael E.; Tian, Junping

2018-03-01

The observation of Higgs pair production at high-energy colliders can give evidence for the presence of a triple Higgs coupling. However, the actual determination of the value of this coupling is more difficult. In the context of general models for new physics, double Higgs production processes can receive contributions from many possible beyond-Standard-Model effects. This dependence must be understood if one is to make a definite statement about the deviation of the Higgs field potential from the Standard Model. In this paper, we study the extraction of the triple Higgs coupling from the process e+e-→Z h h . We show that, by combining the measurement of this process with other measurements available at a 500 GeV e+e- collider, it is possible to quote model-independent limits on the effective field theory parameter c6 that parametrizes modifications of the Higgs potential. We present precise error estimates based on the anticipated International Linear Collider physics program, studied with full simulation. Our analysis also gives new insight into the model-independent extraction of the Higgs boson coupling constants and total width from e+e- data.

Higgs Production and Decay in Models of a Warped Extra Dimension with a Bulk Higgs

OpenAIRE

Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias

2014-01-01

Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS$_5$ space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusio...

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.

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.

Searches for low-mass Higgs and dark bosons at BaBar

Energy Technology Data Exchange (ETDEWEB)

Oberhof, Benjamin, E-mail: benjamin.oberhof@pi.infn.it [INFN sezione di Pisa and Universitá di Pisa, Polo Fibonacci - Edificio C, Largo B. Pontecorvo 3, 56125 - Pisa (Italy)

2013-01-15

We present BaBar latest results for the direct search of a light CP-odd Higgs boson using radiative decays of the ϒ(nS) (n=1,2,3) resonances in different final states. We also present the results for the search of a hidden sector gauge and Higgs bosons using the full BaBar datasample.

Dark side of the Higgs boson

International Nuclear Information System (INIS)

Low, I.; Schwaller, P.; Shaughnessy, G.; Wagner, C.E.M.

2012-01-01

Current limits from the Large Hadron Collider exclude a standard model-like Higgs mass above 150 GeV, by placing an upper bound on the Higgs production rate. We emphasize that, alternatively, the limit could be interpreted as a lower bound on the total decay width of the Higgs boson. If the invisible decay width of the Higgs is of the same order as the visible decay width, a heavy Higgs boson could be consistent with null results from current searches. We propose a method to infer the invisible decay of the Higgs by using the width of the measured h → ZZ → 4 (ell) line shape, and study the effect on the width extraction due to a reduced signal strength. Assuming the invisible decay product is the dark matter, we show that minimal models are tightly constrained by limits from Higgs searches at the LHC and direct detection experiments of dark matter, unless the relic density constraint is relaxed.

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

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

Searches for BSM Higgs Bosons with ATLAS

CERN Document Server

Navarro, Gabriela; The ATLAS collaboration

2015-01-01

The discovery of a Higgs-like boson with a mass of about 125GeV has prompted the question of whether or not this particle is part of a much larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS Experiment regarding Beyond-the-Standard Model (BSM) Higgs hypothesis tests are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal Supersymmetric Standard Model.

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

Higgs inflation and the cosmological constant

Energy Technology Data Exchange (ETDEWEB)

Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2014-02-15

The Higgs not only induces the masses of all SM particles, the Higgs, given its special mass value, is the natural candidate for the inflaton and in fact is ruling the evolution of the early universe, by providing the necessary dark energy which remains the dominant energy density. SM running couplings not only allow us to extrapolate SM physics up to the Planck scale, but equally important they are triggering the Higgs mechanism. This is possible by the fact that the bare mass term in the Higgs potential changes sign at about μ{sub 0}≅1.40 x 10{sup 16} GeV and in the symmetric phase is enhanced by quadratic terms in the Planck mass. Such a huge Higgs mass term is able to play a key role in triggering inflation in the early universe. In this article we extend our previous investigation by working out the details of a Higgs inflation scenario. We show how different terms contributing to the Higgs Lagrangian are affecting inflation. Given the SM and its extrapolation to scales μ>μ{sub 0} we find a calculable cosmological constant V(0) which is weakly scale dependent and actually remains large during inflation. This is different to the Higgs fluctuation field dependent ΔV(φ), which decays exponentially during inflation, and actually would not provide a sufficient amount of inflation. The fluctuation field has a different effective mass which shifts the bare Higgs transition point to a lower value μ'{sub 0} ≅7.7 x 10{sup 14} GeV. The vacuum energy V(0) being proportional to M{sub Pl}{sup 4} has a coefficient which vanishes near the Higgs transition point, such that the bare and the renormalized cosmological constant match at this point. The role of the Higgs in reheating and baryogenesis is emphasized.

Search for a lighter Higgs boson in Two Higgs Doublet Models

Energy Technology Data Exchange (ETDEWEB)

Cacciapaglia, Giacomo; Deandrea, Aldo; Gascon-Shotkin, Suzanne; Corre, Solène Le; Lethuillier, Morgan [University Lyon, Université Claude Bernard Lyon 1, CNRS/IN2P3, UMR5822 IPNL,4, rue E. Fermi, Villeurbanne, F-69622 (France); Tao, Junquan [Institute High Energy Physics, Chinese Academy of Sciences,P.O. Box 918, Beijing, 100049 (China)

2016-12-15

We consider present constraints on Two Higgs Doublet Models, both from the LHC at Run 1 and from other sources in order to explore the possibility of constraining a neutral scalar or pseudo-scalar particle lighter than the 125 GeV Higgs boson. Such a lighter particle is not yet completely excluded by present data. We show with a simplified analysis that some new constraints could be obtained at the LHC if such a search is performed by the experimental collaborations, which we therefore encourage to continue carrying out light diphoton resonance searches at √s=13 TeV in the context of Two Higgs Doublet Models.

Measurement of the Higgs boson coupling with tau leptons and search for an additional neutral MSSM Higgs boson with the ATLAS detector

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00376986

The aim of this thesis is the search for the Standard Model Higgs boson and for additional heavy MSSM Higgs bosons in the $\\tau\\tau$ channel with the ATLAS detector of the LHC. The search for the Higgs boson predicted by the Standard Model is performed using the full integrated luminosity of the Run 1 of the LHC: 4.5 fb$^{-1}$ of data collected at an energy in the center of mass of 7 TeV and 20.3 fb$^{-1}$ of data collected at an energy in the center of mass of 8 TeV. The analysis enhances the sensitivity to signal events by implementing a Boosted Decision Tree trained on the signal and background models. The BDT score distribution shows an excess of data over the background expectation, with an observed (expected) statistical significance of 4.5 $\\sigma$ (3.4 $\\sigma$), which provides evidence for the direct coupling of the Higgs boson to fermions. The measured signal strength normalized to the Standard Model expectation of $\\mu = 1.43^{+0.43}_{-0.37}$ is consistent with the predicted Yukawa coupling strengt...

John Ellis discusses the Higgs, the lack of the Higgs, and extra dimensions

CERN Multimedia

Katarina Anthony

2011-01-01

On 13 September, CERN will be hosting a colloquium to mark John Ellis' 65th birthday. The colloquium comes as John ends his long career as a distinguished CERN staff member and makes a transition to Clerk Maxwell Professor of Theoretical Physics at King’s College London. The Bulletin took the opportunity to ask John to share his expectations from the LHC during this long-awaited data-taking phase...   John Ellis  in his office (July 2011). So, let’s start from the Higgs boson: does it exist and where is it? The million-dollar question… Sometime in the next few months, I think we will finally get clarity on the Higgs boson. While it has been with us as a hypothesis since 1964, I think we are finally closing in on it now. However, in every possible discovery scenario, clarity on the Higgs will lead to new physics. Let me explain... Experiments have left only three possible mass ranges where the Higgs – or a Higgs-like particl...

Where is the Higgs boson?

International Nuclear Information System (INIS)

Aranda, A.; Balazs, C.; Diaz-Cruz, J.L.

2003-01-01

Electroweak precision measurements indicate that the standard model Higgs boson is light and that it could have already been discovered at LEP 2, or might be found at the Tevatron run 2. In the context of a TeV -1 size extra-dimensional model, we argue that the Higgs boson production rates at LEP and the Tevatron are suppressed, while they might be enhanced at the LHC or at CLIC. This is due to the possible mixing between brane and bulk components of the Higgs boson, that is, the non-trivial brane-bulk 'location' of the lightest Higgs. To parametrize this mixing, we consider two Higgs doublets, one confined to the usual space dimensions and the other propagating in the bulk. Calculating the production and decay rates for the lightest Higgs boson, we find that compared to the standard model (SM), the cross section receives a suppression well below but an enhancement close to and above the compactification scale M c . This impacts the discovery of the lightest (SM like) Higgs boson at colliders. To find a Higgs signal in this model at the Tevatron run 2 or at the LC with √s=1.5 TeV, a higher luminosity would be required than in the SM case. Meanwhile, at the LHC or at CLIC with √s∼3-5 TeV one might find highly enhanced production rates. This will enable the latter experiments to distinguish between the extra-dimensional and the SM for M c up to about 6 TeV

Measurements of properties of the Higgs boson in the diphoton decay channel with the full 2016 data set

CERN Document Server

CMS Collaboration

2017-01-01

Measurements of properties of the Higgs boson SM(125) in the $\\mathrm{H}\\rightarrow\\gamma\\gamma$ decay channel are reported. The analysis uses the data collected by the CMS experiment in proton-proton collisions during the 2016 LHC running period. The data sample corresponds to an integrated luminosity of $35.9\\,\\text{fb}^\\text{$-$1}$ at ${\\sqrt{s}=13\\,\\text{Te}\\hspace{-.08em}\\text{V}}$. The measured signal strength relative to the standard model prediction is ${1.16^{+0.15}_{-0.14}=1.16\\ ^{+0.11}_{-0.10}\\text{(stat.)}\\ ^{+0.09}_{-0.08}\\text{(syst.)}\\ ^{+0.06}_{-0.05}\\text{(theo.)}}$. Signal strengths associated with the different Higgs boson production mechanisms, coupling modifiers to bosons and fermions, and effective couplings to photons and gluons are also measured.

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.

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.)

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.

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.

Off-Shell Higgs Probe of Naturalness

Science.gov (United States)

Gonçalves, Dorival; Han, Tao; Mukhopadhyay, Satyanarayan

2018-03-01

Examining the Higgs sector at high energy scales through off-shell Higgs production can potentially shed light on the naturalness problem of the Higgs boson mass. We propose such a study at the LHC by utilizing a representative model with a new scalar field (S ) coupled to the standard model Higgs doublet (H ) in a form |S |2|H |2. In the process p p →h*→Z Z , the dominant momentum-dependent part of the one-loop scalar singlet corrections, especially above the new threshold at 2 mS, leads to a measurable deviation in the differential distribution of the Z -pair invariant mass, in accordance with the quadratic divergence cancellation to the Higgs mass. We find that it is conceivable to probe such new physics at the 5 σ level at the high-luminosity LHC, improving further with the upgraded 27 TeV LHC, without requiring the precise measurement of the Higgs boson total width. The discovery of such a Higgs portal could also have important implications for thermal dark matter as well as for electroweak baryogenesis.

Graceful exit from Higgs G-inflation

Energy Technology Data Exchange (ETDEWEB)

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

2013-09-15

Higgs G-inflation is a Higgs inflation model with a generalized Galileon term added to the standard model Higgs field, which realizes inflation compatible with observations. Recently, it was claimed that the generalized Galileon term induces instabilities during the oscillation phase, and that the simplest Higgs G-inflation model inevitably suffers from this problem. In this paper, we extend the original Higgs G-inflation Lagrangian to a more general form, namely introducing a higher-order kinetic term and generalizing the form of the Galileon term, so that the Higgs field can oscillate after inflation without encountering instabilities. Moreover, it accommodates a large region of the n{sub s}-r plane, most of which is consistent with current observations, leading us to expect the detection of B-mode polarization in the cosmic microwave background in the near future.

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.

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.

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.

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.

LEP Higgs boson searches beyond the standard model

Indian Academy of Sciences (India)

These include the searches for charged Higgs bosons, models with two Higgs field doublets, searches for 'fermiophobic' Higgs decay, invisible Higgs boson decays, decay-mode independent searches, and limits on Yukawa and anomalous Higgs couplings. I review the searches done by the four LEP experiments and ...

Higgs into the heart of imagination

CERN Document Server

Van den Bergh, Hannie

2010-01-01

Higgs is the documentary about the quest for the Higgs particle, also known as "The God Particle". It is considered the missing link in particle physics. Higgs is a film about the curiosity, the passion, and the imaginative power of silence.

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...

Toponium Tests Of Top-Quark Higgs Bags

OpenAIRE

Macpherson, Alick L.; Campbell, Bruce A.

1993-01-01

Recently it has been suggested that top quarks, or very massive fourth generation quarks, might surround themselves with a Higgs "bag" of deformation of the Higgs expectation value from its vacuum magnitude. In this paper we address the question of whether such nonlinear Higgs-top interaction effects are subject to experimental test. We first note that if top quarks were necessarily accompanied by Higgs "bags", then top quark weak decay would involve the sudden disruption of the Higgs "bag", ...

Studying Higgs pair production in the process γγ→H0H0 in the two-Higgs-doublet model

International Nuclear Information System (INIS)

La-Zhen, S.; Yao-Yang, L.

1996-01-01

In the two-Higgs-doublet model the complete nonstandard Higgs boson helicity amplitudes for the Higgs boson pair production process γγ→H 0 H 0 is calculated and explicit formulas for nonstandard Higgs boson contributions to the helicity amplitudes are given. It is shown that the cross section is in the range of 0.03 endash 30 pb at √s=1 TeV, for Higgs boson masses of 350 H 0 <490 GeV in monochromatic γγ collisions. The angular distribution for Higgs pair production is strongly peaked in the forward and backward directions. In particular the angular dependence for Higgs pair production is due to the nonstandard Higgs boson getting larger where the box diagrams constitute the dominant part of the differential cross section. For studying heavy Higgs pair production the use of circularly polarized photon beams with equal helicities is advantageous. copyright 1996 The American Physical Society

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.

Vacuum stability in neutrinophilic Higgs doublet model

International Nuclear Information System (INIS)

Haba, Naoyuki; Horita, Tomohiro

2011-01-01

A neutrinophilic Higgs model has tiny vacuum expectation value (VEV), which can naturally explain tiny masses of neutrinos. There is a large energy scale hierarchy between a VEV of the neutrinophilic Higgs doublet and that of usual standard model-like Higgs doublet. In this Letter we at first analyze vacuum structures of Higgs potential in both supersymmetry (SUSY) and non-SUSY neutrinophilic Higgs models, and next investigate a stability of this VEV hierarchy against radiative corrections. We will show that the VEV hierarchy is stable against radiative corrections in both Dirac neutrino and Majorana neutrino scenarios in both SUSY and non-SUSY neutrinophilic Higgs doublet models.

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.

Stability of the minimum of a SO(N)-invariant Higgs potential with reducible Higgs fields

International Nuclear Information System (INIS)

Thornburg, R.J.

1986-01-01

The present work takes up the problem of finding the absolute minimum of a SO(N)-invariant Higgs potential for the reducible representation of Higgs fields consisting of the antisymmetric (A) and symmetric (S) traceless second-rank tensors. The stability of the minimum under changes on the potential's parameters is also investigated. Potentials containing S alone, both A and S coupled by a positive semi-definite term are minimized. Eigenstates of the Higgs mass matrix are calculated and related to the behavior of the SO(N)-action. Previous results relying on the absence of pseudo-Goldstone models and a new application of the geometry of the action show that the minimum is stable under small changes of the parameters. It is thus stable in an open region of the full eleven-dimensional parameter space of the most general potential of its kind. The isotropy group of the minimum is found to be either SO(N-p) x SO(p-2) x SO(2) or U({N-p}/2) x U(p/2), and the relative magnitudes of the vacuum expectation values of A and S are not constrained. For SO(10), U(3) x U(2) contains the standard model. One-loop Renormalization Group β-functions are calculated for all parameters of the model

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.)

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...

Scalar field dark matter and the Higgs field

Directory of Open Access Journals (Sweden)

O. Bertolami

2016-08-01

Full Text Available We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10−6–10−4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall–Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.

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.

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

Higgs mixing in the NMSSM and light higgsinos

International Nuclear Information System (INIS)

Jeong, Kwang Sik; Shoji, Yutaro; Yamaguchi, Masahiro

2014-12-01

We explore the effects of Higgs mixing in the general next-to-minimal supersymmetric Standard Model (NMSSM). Extended to include a gauge singlet, the Higgs sector can naturally explain the observed Higgs boson mass in TeV scale supersymmetry without invoking large stop mixing. This is particularly the case when the singlet scalar is light so that singlet-doublet mixing increases the mass of the SM-like Higgs boson. In such a case the Higgs mixing has interesting implications following from the fact that the higgsino mass parameter and the singlet coupling to Higgs bilinear crucially depend on the Higgs boson masses and mixing angles. For the mixing compatible with the current LHC data on the Higgs signal rates, the higgsinos are required to be relatively light, around or below a few hundred GeV, as long as the heavy doublet Higgs boson has a mass smaller than about 250√(tanβ) GeV and the singlet-like Higgs boson is consistent with the LEP constraint. In addition, the Higgs coupling to photons can receive a sizable contribution of either sign from the charged-higgsino loops combined with singlet-doublet mixing.

Difficult scenarios for NMSSM Higgs discovery at the LHC

International Nuclear Information System (INIS)

Ellwanger, Ulrich; Gunion, John F.; Hugonie, Cyril

2005-01-01

We identify scenarios not ruled out by LEP data in which NMSSM Higgs detection at the LHC will be particularly challenging. We first review the 'no-lose' theorem for Higgs discovery at the LHC that applies if Higgs bosons do not decay to other Higgs bosons - namely, with L = 300 fb -1 , there is always one or more 'standard' Higgs detection channel with at least a 5σ signal. However, we provide examples of no-Higgs-to-Higgs cases for which all the standard signals are no larger than 7σ implying that if the available L is smaller or the simulations performed by ATLAS and CMS turn out to be overly optimistic, all standard Higgs signals could fall below 5σ even in the no-Higgs-to-Higgs part of NMSSM parameter space. In the vast bulk of NMSSM parameter space, there will be Higgs-to-Higgs decays. We show that when such decays are present it is possible for all the standard detection channels to have very small significance. In most such cases, the only strongly produced Higgs boson is one with fairly SM-like couplings that decays to two lighter Higgs bosons (either a pair of the lightest CP-even Higgs bosons, or, in the largest part of parameter space, a pair of the lightest CP-odd Higgs bosons). A number of representative bench-mark scenarios of this type are delineated in detail and implications for Higgs discovery at various colliders are discussed

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.

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.

Putting a Stop to di-Higgs Modifications

CERN Document Server

Batell, Brian; Stolarski, Daniel; Verhaaren, Christopher B

2015-01-01

Pair production of Higgs bosons at hadron colliders is an enticing channel to search for new physics. New colored particles that couple strongly to the Higgs, such as those most often called upon to address the hierarchy problem, provide well motivated examples in which large enhancements of the di-Higgs rate are possible, at least in principle. However, in such scenarios the di-Higgs production rate is tightly correlated with the single Higgs production rate and, since the latter is observed to be SM-like, one generally expects that only modest enhancements in di-Higgs production are allowed by the LHC Run 1 data. We examine the contribution of top squarks (stops) in a simplified supersymmetry model to di-Higgs production and find that this general expectation is indeed borne out. In particular, the allowed deviations are typically small, but there are tuned regions of parameter space where expectations based on EFT arguments break down in which order 100% enhancements to the di-Higgs production rate are pos...

Effective Field Theory with Two Higgs Doublets

CERN Document Server

Crivellin, Andreas; Procura, Massimiliano

2016-01-01

In this article we extend the effective field theory framework describing new physics effects to the case where the underlying low-energy theory is a Two-Higgs-Doublet model. We derive a complete set of independent operators up to dimension six assuming a $Z_2$-invariant CP-conserving Higgs potential. The effects on Higgs and gauge boson masses, mixing angles in the Higgs sector as well as couplings to fermions and gauge bosons are computed. At variance with the case of a single Higgs doublet, we find that pair production of SM-like Higgses, arising through dimension-six operators, is not fixed by fermion-fermion-Higgs couplings and can therefore be sizable.

Cosmological perturbations in the new Higgs inflation

Energy Technology Data Exchange (ETDEWEB)

Germani, Cristiano [Arnold Sommerfeld Center, Ludwig-Maximilians-University, Theresienstr, 37 80333 Muenchen (Germany); Kehagias, Alex, E-mail: cristiano.germani@lmu.de, E-mail: kehagias@central.ntua.gr [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece)

2010-05-01

We study the cosmological perturbations created during the New Higgs inflationary phase. In the New Higgs Inflation, the Higgs boson is kinetically coupled to the Einstein tensor and only three perturbative degrees of freedom, a scalar and two tensorial (gravitational waves), propagate during Inflation. Scalar perturbations are found to match the latest WMAP-7yrs data within Standard Model Higgs parameters. Primordial gravitational waves also, although propagating with superluminal speed, are consistent with present data. Finally, we estimate the values of the parameter of the New Higgs Inflation in relation to the Higgs mass, the spectral index and amplitude of the primordial scalar perturbations showing that the unitarity bound of the theory is not violated.

Searches for non-Standard Model Higgs bosons

CERN Document Server

Dumitriu, Ana Elena; The ATLAS collaboration

2018-01-01

This presentation focuses on the Searches for non-Standard Model Higgs bosons using 36.1 fb of data collected by the ATLAS experiment. There are several theoretical models with an extended Higgs sector considered: 2 Higgs Doublet Models (2HDM), Supersymmetry (SUSY), which brings along super-partners of the SM particles (+ The Minimal Supersymmetric Standard Model (MSSM), whose Higgs sector is equivalent to the one of a constrained 2HDM of type II and the next-to MSSM (NMSSM)), General searches and Invisible decaying Higgs boson.

Maximal CP violation via Higgs-boson exchange

International Nuclear Information System (INIS)

Lavoura, L.

1992-01-01

The unitarity of the mixing matrix of the charged Higgs bosons, and the orthogonality of the mixing matrix of the neutral Higgs bosons, are used to derive upper bounds on the values of general CP-violating expressions. The bounds are independent of the total number of Higgs fields in any specific model. They allow is to relax the usual assumption of only one Higgs boson being light. It is natural that the CP violation in the exchange of neutral Higgs bosons between bottom quarks be particularly large

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.)

Machine Learning wins the Higgs Challenge

CERN Multimedia

Abha Eli Phoboo

2014-01-01

The winner of the four-month-long Higgs Machine Learning Challenge, launched on 12 May, is Gábor Melis from Hungary, followed closely by Tim Salimans from the Netherlands and Pierre Courtiol from France. The challenge explored the potential of advanced machine learning methods to improve the significance of the Higgs discovery.   Winners of the Higgs Machine Learning Challenge: Gábor Melis and Tim Salimans (top row), Tianqi Chen and Tong He (bottom row). Participants in the Higgs Machine Learning Challenge were tasked with developing an algorithm to improve the detection of Higgs boson signal events decaying into two tau particles in a sample of simulated ATLAS data* that contains few signal and a majority of non-Higgs boson “background” events. No knowledge of particle physics was required for the challenge but skills in machine learning - the training of computers to recognise patterns in data – were essential. The Challenge, hosted by Ka...

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.

Minkowski space structure of the Higgs potential in the two-Higgs-doublet model. II. Minima, symmetries, and topology

International Nuclear Information System (INIS)

Ivanov, I. P.

2008-01-01

We continue to explore the consequences of the recently discovered Minkowski space structure of the Higgs potential in the two-Higgs-doublet model. Here, we focus on the vacuum properties. The search for extrema of the Higgs potential is reformulated in terms of 3-quadrics in the 3+1-dimensional Minkowski space. We prove that 2HDM cannot have more than two local minima in the orbit space and that a twice-degenerate minimum can arise only via spontaneous violation of a discrete symmetry of the Higgs potential. Investigating topology of the 3-quadrics, we give concise criteria for existence of noncontractible paths in the Higgs orbit space. We also study explicit symmetries of the Higgs potential/Lagrangian and their spontaneous violation from a wider perspective than usual

Composite Higgs-mediated flavor-changing neutral current

International Nuclear Information System (INIS)

Agashe, Kaustubh; Contino, Roberto

2009-01-01

We discuss how, in the presence of higher-dimensional operators, the standard model fermion masses can be misaligned in flavor space with the Yukawa couplings to the Higgs boson, even with only one Higgs doublet. Such misalignment results in flavor-violating couplings to the Higgs and hence flavor-changing neutral current processes from tree-level Higgs exchange. We perform a model-independent analysis of such an effect. Specializing to the framework of a composite Higgs with partially composite standard model gauge and fermion fields, we show that the constraints on the compositeness scale implied by ε K can be generically as strong as those from the exchange of heavy spin-1 resonances if the Higgs is light and strongly coupled to the new states. In the special and well-motivated case of a composite pseudo-Goldstone Higgs, we find that the shift symmetry acting on the Higgs forces an alignment of the fermion mass terms with their Yukawa couplings at leading order in the fermions' degree of compositeness, thus implying much milder bounds. As a consequence of the flavor-violating Higgs couplings, we estimate BR(t→ch)∼10 -4 and BR(h→tc)∼5x10 -3 both for a pseudo-Goldstone (if t R is fully composite) and for a generic composite Higgs. By virtue of the AdS/CFT correspondence, our results directly apply to 5-dimensional Randall-Sundrum compactifications.

Upper and lower Higgs boson mass bounds from a lattice Higgs-Yukawa model with dynamical overlap fermions

International Nuclear Information System (INIS)

Gerhold, Philipp; Jansen, Karl

2009-12-01

We study a lattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure as in the Higgs sector of the electroweak Standard Model, in particular, obeying a Ginsparg- Wilson version of the underlying SU(2) L x U(1) Y symmetry, being a global symmetry here due to the neglection of gauge fields in this model. In this paper we present our results on the cutoffdependent upper Higgs boson mass bound at several selected values of the cutoff parameter Λ. (orig.)

Co-Higgs bundles on P^1

OpenAIRE

Rayan, Steven

2010-01-01

Co-Higgs bundles are Higgs bundles in the sense of Simpson, but with Higgs fields that take values in the tangent bundle instead of the cotangent bundle. Given a vector bundle on P^1, we find necessary and sufficient conditions on its Grothendieck splitting for it to admit a stable Higgs field. We characterize the rank-2, odd-degree moduli space as a universal elliptic curve with a globally-defined equation. For ranks r=2,3,4, we explicitly verify the conjectural Betti numbers emerging from t...

Strongly interacting Higgs sector without technicolor

International Nuclear Information System (INIS)

Liu Chuan; Kuti, J.

1994-12-01

Simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with a higher derviative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection. As a finite and unitary theory in the continuum, this model serves as an explicit and simple example of a strong interacting Higgs sector without technicolor. (orig.)

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

Difficult Scenarios for NMSSM Higgs Discovery at the LHC

CERN Document Server

Ellwanger, U; Hugonie, C; Ellwanger, Ulrich; Gunion, John F.; Hugonie, Cyril

2005-01-01

We identify scenarios not ruled out by LEP data in which NMSSM Higgs detection at the LHC will be particularly challenging. We first review the `no-lose' theorem for Higgs discovery at the LHC that applies if Higgs bosons do not decay to other Higgs bosons - namely, with L=300 fb^-1, there is always one or more `standard' Higgs detection channel with at least a 5 sigma signal. However, we provide examples of no-Higgs-to-Higgs cases for which all the standard signals are no larger than 7 sigma implying that if the available L is smaller or the simulations performed by ATLAS and CMS turn out to be overly optimistic, all standard Higgs signals could fall below 5 sigma even in the no-Higgs-to-Higgs part of NMSSM parameter space. In the vast bulk of NMSSM parameter space, there will be Higgs-to-Higgs decays. We show that when such decays are present it is possible for all the standard detection channels to have very small significance. In most such cases, the only strongly produced Higgs boson is one with fairly S...

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.)

Higgs physics at a future e+e- linear collider

International Nuclear Information System (INIS)

Schumacher, M.

2001-01-01

This letter reviews the potential of a high luminosity e + e - linear collider (LC) in the precision study of the Higgs boson profile. The complementarity with the large hadron collider (LHC) Higgs physics program is briefly discussed. At the LC the Higgs mass can be best measured exploiting the kinematics in the Higgs-strahlung process: e + e - → Z → ZH. Spin, parity and charge-conjugation quantum numbers of the Higgs boson can be determined in a model-independent way. At the LC the Higgs boson production and decay rates can be used to measure the Higgs couplings to gauge bosons and fermions. Several extensions of the SM model introduce additional Higgs doublets and singlets. A no loose theorem guarantees that in a general supersymmetric model embedded in a GUT scenario at least one Higgs boson will be observable at √s = 500 GeV with L = 500 fb -1 . At the LHC the SM Higgs boson or at least one Higgs boson in the MSSM will be observed. Beyond its discovery a limited number of measurements of Higgs boson properties can be carried out at the LHC (mass, total width for a heavy Higgs boson, some ratios of couplings). The complementary of LC over LHC concerning the Higgs sector is threefold: first the accuracy of these measurements will be increased, secondly the absolute measurements of all the relevant Higgs boson couplings, including the Higgs self coupling, will be possible only at LC, and finally extended Higgs sector scenarios can be observed at LC closing the loopholes of a possible non-discovery at the LHC

The Higgs boson resonance width from a chiral Higgs-Yukawa model on the lattice

International Nuclear Information System (INIS)

Gerhold, Philipp; Kallarackal, Jim; Humboldt-Universitaet, Berlin; Jansen, Karl

2011-11-01

The Higgs boson is a central part of the electroweak theory and is crucial to generate masses for quarks, leptons and the weak gauge bosons. We use a 4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the electroweak model to compute physical quantities in the path integral approach which is evaluated by means of Monte Carlo simulations thus allowing for fully non perturbative calculations. The chiral symmetry of the model is incorporated by using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa model does not involve the weak gauge bosons and furthermore, only a degenerate doublet of top- and bottom quarks are incorporated. The goal of this work is to study the resonance properties of the Higgs boson and its sensitivity to the strength of the quartic self coupling. (orig.)

Finding the Higgs boson: A status report

International Nuclear Information System (INIS)

Dawson, S.

1995-01-01

The search for the Higgs boson of the minimal Standard Model has been a major focus of experimental high energy physics for some years now. Here, the authors review the current experimental limits and discuss the prospects for finding the Higgs boson at future accelerators, such as LEPII and the LHC. They consider only the Standard Model Higgs boson. Since a null result which definitively excluded a Higgs boson below some mass scale would be extremely important, they emphasize the case where the Higgs boson is much heavier than the relevant collider energy (or where there is no Higgs boson at all). Many of the results given here are a summary of those obtained by the DPF Committee on Long Term Planning

The Nobel Prize winner in physics 2013--Peter Higgs

International Nuclear Information System (INIS)

Liu Jinyan

2014-01-01

Peter Higgs is a famous English physicist who was known for his works on Higgs mechanism and Higgs particle. He won the 2013 Noble Prize in physics. This paper briefly outlines his life, the proposition of Higgs mechanism and the origin of the name of Higgs particle. The discovery of Higgs particle is also given here. (author)

Disentangling Higgs-Top Couplings in Associated Production

CERN Document Server

Ellis, John; Sakurai, Kazuki; Takeuchi, Michihisa

2014-01-01

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, $\\kappa_t$ and ${\\tilde \\kappa_t}$, which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-$\\gamma$-$\\gamma$ couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints on ${\\tilde \\kappa_t}$, if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributions. We discuss methods to measure directly the scalar and pseudoscalar Higgs-top couplings by measurements of Higgs production in association with ${\\bar t} t$, single $t$ and single ${\\bar t}$ at the LHC. Measurements of the total cross sections are very sensitive to variations in the Higgs-top couplings that are consistent with the present indirect constraints, as are invariant mass distributions in ${\\bar t} t H$, $tH$ and ${\\bar t} H$ final states. We also investigate the addition...

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...

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.

Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

Energy Technology Data Exchange (ETDEWEB)

Yu, Shin-Shan [Taiwan, Natl. Central U.; Chekanov, Sergei [Argonne; Gray, Lindsey [Fermilab; Kotwal, Ashutosh [Duke U.; Sen, Sourav [Duke U.; Tran, Nhan Viet [Fermilab

2016-11-04

We study the detector performance in the reconstruction of hadronically-decaying W bosons and Higgs bosons at very high energy proton colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs bosons carry transverse momentum in the multi-TeV range, which results in collimated decay products that are reconstructed as a single jet. We present a measurement of the energy response and resolution of boosted W-jets and Higgs-jets and show the separation of two sub-jets within the boosted boson jet.

Flavor changing heavy Higgs interactions at the LHC

Directory of Open Access Journals (Sweden)

Baris Altunkaynak

2015-12-01

Full Text Available A general two Higgs doublet model (2HDM is adopted to study the signature of flavor changing neutral Higgs (FCNH decay ϕ0→tc¯+t¯c, where ϕ0 could be a CP-even scalar (H0 or a CP-odd pseudoscalar (A0. Measurement of the light 125 GeV neutral Higgs boson (h0 couplings at the Large Hadron Collider (LHC favor the decoupling limit or the alignment limit of a 2HDM, in which gauge boson and diagonal fermion couplings of h0 approach Standard Model values. In such limit, FCNH couplings of h0 are naturally suppressed by a small mixing parameter cos⁡(β−α, while the off-diagonal couplings of heavier neutral scalars ϕ0 are sustained by sin⁡(β−α∼1. We study physics background from dominant processes with realistic acceptance cuts and tagging efficiencies. Promising results are found for the LHC running at 13 or 14 TeV collision energies.

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.

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)

Higgs decays and brane gravi-vectors

International Nuclear Information System (INIS)

Clark, T. E.; Liu Boyang; Love, S. T.; Xiong, C.; Veldhuis, T. ter

2008-01-01

Higgs boson decays in flexible brane world models with stable, massive gravi-vectors are considered. Such vectors couple bilinearly to the standard model fields through either the standard model energy-momentum tensor, the weak hypercharge field strength, or the Higgs scalar. The role of the coupling involving the extrinsic curvature is highlighted. It is found that within the presently allowed parameter space, the decay rate of the Higgs into two gravi-vectors (which would appear as an invisible Higgs decay) can be comparable to the rate for any of the standard model decay modes.

The hunt for the Higgs particle

CERN Multimedia

CERN. Geneva

2007-01-01

With the advent of the LHC, the hunt for the Higgs boson enters its crucial phase. These three lectures will review: the Higgs mechanism; its implementation in the minimal Standard Model; possible alternatives with and without elementary scalar fields; the presently available information on electroweak gauge symmetry breaking and the Higgs particle; the properties of the Higgs boson(s) in the Standard Model and its supersymmetric extensions; the strategies for direct searches at colliders, with emphasis on the LHC, and comments on the possible scenarios that may emerge.

New Physics and novel Higgs signals

International Nuclear Information System (INIS)

Diaz-Cruz, J. Lorenzo

2003-01-01

We review some of the results of our recent work dealing with the novel type of Higgs signals that arise when one considers extensions of the standard model. We discuss first possible deviations on the Higgs couplings due to heavy particles, in the context of the MSSM and with large extra-dimensions. Then, we present several models where it is possible to induce flavor violating Higgs couplings, and probe them at future hadron colliders through the LFV Higgs decay h → τμ or with rare top decays

Bounding the Higgs boson width through interferometry.

Science.gov (United States)

Dixon, Lance J; Li, Ye

2013-09-13

We study the change in the diphoton-invariant-mass distribution for Higgs boson decays to two photons, due to interference between the Higgs resonance in gluon fusion and the continuum background amplitude for gg→γγ. Previously, the apparent Higgs mass was found to shift by around 100 MeV in the standard model in the leading-order approximation, which may potentially be experimentally observable. We compute the next-to-leading-order QCD corrections to the apparent mass shift, which reduce it by about 40%. The apparent mass shift may provide a way to measure, or at least bound, the Higgs boson width at the Large Hadron Collider through "interferometry." We investigate how the shift depends on the Higgs width, in a model that maintains constant Higgs boson signal yields. At Higgs widths above 30 MeV, the mass shift is over 200 MeV and increases with the square root of the width. The apparent mass shift could be measured by comparing with the ZZ* channel, where the shift is much smaller. It might be possible to measure the shift more accurately by exploiting its strong dependence on the Higgs transverse momentum.

Higgs as a holographic pseudo-Goldstone boson

International Nuclear Information System (INIS)

Contino, Roberto; Nomura, Yasunori; Pomarol, Alex

2003-01-01

The AdS/CFT correspondence allows one to relate 4D strongly coupled theories to weakly coupled theories in 5D AdS. We use this correspondence to study a scenario in which the Higgs appears as a composite pseudo-Goldstone boson (PGB) of a strongly coupled theory. We show how a non-linearly realized global symmetry protects the Higgs mass and guarantees the absence of quadratic divergences at any loop order. The gauge and Yukawa interactions for the PGB Higgs are simple to introduce in the 5D AdS theory, and their one-loop contributions to the Higgs potential are calculated using perturbation theory. These contributions are finite, giving a squared-mass to the Higgs which is one-loop smaller than the mass of the first Kaluza-Klein state. We also show that if the symmetry breaking is caused by boundary conditions in the extra dimension, the PGB Higgs corresponds to the fifth component of the bulk gauge boson. To make the model fully realistic, a tree-level Higgs quartic coupling must be induced. We present a possible mechanism to generate it and discuss the conditions under which an unwanted large Higgs mass term is avoided

New physics searches with Higgs-photon associated production at the Higgs factory

Science.gov (United States)

Ren, Hong-Yu

2015-11-01

A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e+ e- →γh could be a useful channel for new physics. We express new physics model-independently in the effective Lagrangian approach, and find that the new physics effects of γh have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculate for the first time the 95% confidence level(CL) bounds of γh at the Higgs factory, and prove that γh is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run. Supported by National Natural Science Foundation of China (11275102) and Tsinghua Scholarship for Overseas Graduate Studies

Measuring the CP state of tau lepton pairs from Higgs decay at the ILC

OpenAIRE

Jeans, D.; Wilson, G. W.

2018-01-01

In the Standard Model, the Higgs boson is a CP even state with CP conserving couplings; any deviations from this would be a sign of new physics. These CP properties can be probed by measuring Higgs decays to tau lepton pairs: the transverse correlation between the tau spins depends on CP. This paper develops such an analysis, using full simulation of signal and background events in the International Large Detector concept for the International Linear Collider. We consider Higgs-strahlung even...

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.

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}}

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.

Higgs bosons in supersymmetric models. Pt. 1

International Nuclear Information System (INIS)

Gunion, J.F.

1986-01-01

We describe the properties of Higgs bosons in a class of supersymmetric theories. We consider models in which the low-energy sector contains two weak complex doublets and perhaps one complex gauge-singlet Higgs field. Supersymmetry is assumed to be either softly or spontaneously broken, thereby imposing a number of restrictions on the Higgs boson parameters. We elucidate the Higgs boson masses and present Feynman rules for their couplings to the gauge bosons, fermions and scalars of the theory. We also present Feynman rules for vertices which are related by supersymmetry to the above couplings. Exact analytic expressions are given in two useful limits - one corresponding to the absence of the gauge-singlet Higgs field and the other corresponding to the absence of a supersymmetric Higgs mass term. (orig.)

Pauline Gagnon's blog post: I’m a Higgs gatherer, not a Higgs hunter!

CERN Multimedia

Pauline Gagnon

2011-01-01

Ever since four theorists published their “Higgs hunter’s guide” in 1990, people have been referring to the Higgs hunt, as if we were a bunch of bloodthirsty physicists out for a kill. I’d say, if the search for the Higgs is a safari, at most it’s going to be a photo safari!   The way it works is purely based on statistics. With the ATLAS and CMS detectors, we collect millions of “events” every day, each event being a snapshot of what happened after two protons collided in the Large Hadron Collider (LHC). All sorts of particles are created out of the highly concentrated energy coming from these head-on collisions, some more often than others. Whatever happens often, we know very well by now, having had plenty of opportunities to study them in the past. What’s left now is everything that is hard to do, like catching rare events such as those containing Higgs bosons. And for ...

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...

Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

International Nuclear Information System (INIS)

Chien, Y.T.; Cirigliano, V.; Dekens, W.; Vries, J. de; Mereghetti, E.

2016-01-01

We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section and branching ratios measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.

Probing hidden sector photons through the Higgs window

International Nuclear Information System (INIS)

Ahlers, M.

2008-07-01

We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the Standard Model Higgs via a renormalizable quartic term - sometimes called the Higgs Portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone. (orig.)

Probing hidden sector photons through the Higgs window

International Nuclear Information System (INIS)

Ahlers, Markus; Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas

2008-01-01

We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the standard model Higgs via a renormalizable quartic term - sometimes called the Higgs portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs, we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone.

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.

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

The Higgs vacuum uplifted. Revisiting the electroweak phase transition with a second Higgs doublet

Energy Technology Data Exchange (ETDEWEB)

Dorsch, G.C. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Huber, S.J. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Mimasu, K. [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy; Louvain Univ. Catholique, Louvain-la-Neuve (Belgium). Center for Cosmology, Particle Physics and Phenomenology; No, J.M. [King' s College, London (United Kingdom). Dept. of Physics; Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy

2017-05-25

The existence of a second Higgs doublet in Nature could lead to a cosmological first order electroweak phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We explore the parameter space of such a two-Higgs-doublet-model and show that a first order electroweak phase transition strongly correlates with a significant uplifting of the Higgs vacuum w.r.t. its Standard Model value. We then obtain the spectrum and properties of the new scalars H{sub 0}, A{sub 0} and H{sup ±} that signal such a phase transition, showing that the decay A{sub 0}→H{sub 0}Z at the LHC and a sizable deviation in the Higgs self-coupling λ{sub hhh} from its SM value are sensitive indicators of a strongly first order electroweak phase transition in the 2HDM.

Higgs-gauge boson interactions in the economical 3-3-1 model

International Nuclear Information System (INIS)

Phung Van Dong; Hoang Ngoc Long; Dang Van Soa

2006-01-01

Interactions among the standard model gauge bosons and scalar fields in the framework of the SU(3) C xSU(3) L xU(1) X gauge model with minimal (economical) Higgs content are presented. From these couplings, all scalar fields including the neutral scalar h and the Goldstone bosons can be identified and their couplings with the usual gauge bosons such as the photon, the charged W ± , and the neutral Z, without any additional conditions, are recovered. In the effective approximation, the full content of the scalar sector can be recognized. The CP-odd part of the Goldstone associated with the neutral non-Hermitian bilepton gauge boson G X 0 is decoupled, while its CP-even counterpart has the mixing in the same way in the gauge boson sector. Masses of the new neutral Higgs boson H 1 0 and the neutral non-Hermitian bilepton X 0 are dependent on a coefficient of Higgs self-coupling (λ 1 ). Similarly, masses of the singly charged Higgs boson H 2 ± and of the charged bilepton Y ± are proportional through a coefficient of Higgs self-interaction (λ 4 ). The hadronic cross section for production of this Higgs boson at the CERN LHC in the effective vector boson approximation is calculated. Numerical evaluation shows that the cross section can exceed 260 fb

A global view on the Higgs self-coupling

International Nuclear Information System (INIS)

Di Vita, S.; Grojean, C.; Humboldt-Universitaet, Berlin; Panico, G.; Riembau, M.; Vantalon, T.; Barcelona Institute of Science and Technology, Bellaterra

2017-04-01

The Higgs self-coupling is notoriously intangible at the LHC. It was recently proposed to probe the trilinear Higgs interaction through its radiative corrections to single-Higgs processes. This approach however requires to disentangle these effects from those associated to deviations of other Higgs-couplings to fermions and gauge bosons. We show that a global fit exploiting only single-Higgs inclusive data suffers from degeneracies that prevent one from extracting robust bounds on each individual coupling. We show how the inclusion of double-Higgs production via gluon fusion, and the use of differential measurements in the associated single-Higgs production channels WH, ZH and t anti tH, can help to overcome the deficiencies of a global Higgs-couplings fit. In particular, we bound the variations of the Higgs trilinear self-coupling relative to its SM value to the interval [0.1, 2.3] at 68% confidence level at the high-luminosity LHC, and we discuss the robustness of our results against various assumptions on the experimental uncertainties and the underlying new physics dynamics. We also study how to obtain a parametrically enhanced deviation of the Higgs self-couplings and we estimate how large this deviation can be in a self-consistent effective field theory framework.

A global view on the Higgs self-coupling

Energy Technology Data Exchange (ETDEWEB)

Di Vita, S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Grojean, C. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Panico, G. [Barcelona Institute of Science and Technology, Bellaterra (Spain). IFAE; Riembau, M.; Vantalon, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Barcelona Institute of Science and Technology, Bellaterra (Spain). IFAE

2017-04-15

The Higgs self-coupling is notoriously intangible at the LHC. It was recently proposed to probe the trilinear Higgs interaction through its radiative corrections to single-Higgs processes. This approach however requires to disentangle these effects from those associated to deviations of other Higgs-couplings to fermions and gauge bosons. We show that a global fit exploiting only single-Higgs inclusive data suffers from degeneracies that prevent one from extracting robust bounds on each individual coupling. We show how the inclusion of double-Higgs production via gluon fusion, and the use of differential measurements in the associated single-Higgs production channels WH, ZH and t anti tH, can help to overcome the deficiencies of a global Higgs-couplings fit. In particular, we bound the variations of the Higgs trilinear self-coupling relative to its SM value to the interval [0.1, 2.3] at 68% confidence level at the high-luminosity LHC, and we discuss the robustness of our results against various assumptions on the experimental uncertainties and the underlying new physics dynamics. We also study how to obtain a parametrically enhanced deviation of the Higgs self-couplings and we estimate how large this deviation can be in a self-consistent effective field theory framework.

On-shell neutral Higgs bosons in the NMSSM with complex parameters

Energy Technology Data Exchange (ETDEWEB)

Domingo, Florian [Universidad Autonoma de Madrid, Instituto de Fisica Teorica (UAM/CSIC), Cantoblanco, Madrid (Spain); Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Drechsel, Peter; Passehr, Sebastian [Deutsches Elektronensynchrotron DESY, Hamburg (Germany)

2017-08-15

The Next-to-Minimal Supersymmetric Standard model (NMSSM) appears as an interesting candidate for the interpretation of the Higgs measurement at the LHC and as a rich framework embedding physics beyond the Standard Model. We consider the renormalization of the Higgs sector of this model in its CP-violating version, and propose a renormalization scheme for the calculation of on-shell Higgs masses. Moreover, the connection between the physical states and the tree-level ones is no longer trivial at the radiative level: a proper description of the corresponding transition thus proves necessary in order to calculate Higgs production and decays at a consistent loop order. After discussing these formal aspects, we compare the results of our mass calculation to the output of existing tools. We also study the relevance of the on-shell transition matrix in the example of the h{sub i} → τ{sup +}τ{sup -} width. We find deviations between our full prescription and popular approximations that can exceed 10%. (orig.)

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.

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.

ISR corrections to associated HZ production at future Higgs factories

Science.gov (United States)

Greco, Mario; Montagna, Guido; Nicrosini, Oreste; Piccinini, Fulvio; Volpi, Gabriele

2018-02-01

We evaluate the QED corrections due to initial state radiation (ISR) to associated Higgs boson production in electron-positron (e+e-) annihilation at typical energies of interest for the measurement of the Higgs properties at future e+e- colliders, such as CEPC and FCC-ee. We apply the QED Structure Function approach to the four-fermion production process e+e- →μ+μ- b b bar , including both signal and background contributions. We emphasize the relevance of the ISR corrections particularly near threshold and show that finite third order collinear contributions are mandatory to meet the expected experimental accuracy. We analyze in turn the rôle played by a full four-fermion calculation and beam energy spread in precision calculations for Higgs physics at future e+e- colliders.

Study of the Standard Model Higgs boson decaying to taus at CMS

CERN Document Server

Botta, Valeria

2017-01-01

The most recent search for the Standard Model Higgs boson decaying to a pair of $\\tau$ leptons is performed using proton-proton collision events at a centre-of-mass energy of 13~TeV, recorded by the CMS experiment at the LHC. The full 2016 dataset, corresponding to an integrated luminosity of 35.9~fb$^{-1}$, has been analysed. The Higgs boson signal in the $\\tau^{+}\\tau^{-}$ decay mode is observed with a significance of 4.9 standard deviations, to be compared to an expected significance of 4.7 standard deviations. This measurement is the first observation of the Higgs boson decay into fermions by a single experiment.

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.

Stable Higgs Bosons - new candidate for cold dark matter

International Nuclear Information System (INIS)

Hosotani, Yutaka

2010-01-01

The Higgs boson is in the backbone of the standard model of electroweak interactions. It must exist in some form for achieving unification of interactions. In the gauge-Higgs unification scenario the Higgs boson becomes a part of the extra-dimensional component of gauge fields. The Higgs boson becomes absolutely stable in a class of the gauge-Higgs unification models, serving as a promising candidate for cold dark matter in the universe. The observed relic abundance of cold dark matter is obtained with the Higgs mass around 70 GeV. The Higgs-nucleon scattering cross section is found to be close to the recent CDMS II XENON10 bounds in the direct detection of dark matter. In collider experiments stable Higgs bosons are produced in a pair, appearing as missing energies momenta so that the way of detecting Higgs bosons must be altered.

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

Heavy Higgs bosons at 14 TeV and 100 TeV

Energy Technology Data Exchange (ETDEWEB)

Hajer, Jan [Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong S.A.R., P.R.C. (China); Jockey Club Institute for Advanced Study,The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong S.A.R., P.R.C. (China); Li, Ying-Ying; Liu, Tao; Shiu, John F.H. [Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong S.A.R., P.R.C. (China)

2015-11-18

Searching for Higgs bosons beyond the Standard Model (BSM) is one of the most important missions for hadron colliders. As a landmark of BSM physics, the MSSM Higgs sector at the LHC is expected to be tested up to the scale of the decoupling limit of O(1) TeV, except for a wedge region centered around tan β∼3–10, which has been known to be difficult to probe. In this article, we present a dedicated study testing the decoupled MSSM Higgs sector, at the LHC and a next-generation pp-collider, proposing to search in channels with associated Higgs productions, with the neutral and charged Higgs further decaying into tt and tb, respectively. In the case of neutral Higgs we are able to probe for the so far uncovered wedge region via pp→bbH/A→bbtt. Additionally, we cover the the high tan β range with pp→bbH/A→bbττ. The combination of these searches with channels dedicated to the low tan β region, such as pp→H/A→tt and pp→ttH/A→tttt potentially covers the full tan β range. The search for charged Higgs has a slightly smaller sensitivity for the moderate tan β region, but additionally probes for the higher and lower tan β regions with even greater sensitivity, via pp→tbH{sup ±}→tbtb. While the LHC will be able to probe the whole tan β range for Higgs masses of O(1) TeV by combining these channels, we show that a future 100 TeV pp-collider has a potential to push the sensitivity reach up to ∼O(10) TeV. In order to deal with the novel kinematics of top quarks produced by heavy Higgs decays, the multivariate Boosted Decision Tree (BDT) method is applied in our collider analyses. The BDT-based tagging efficiencies of both hadronic and leptonic top-jets, and their mutual fake rates as well as the faking rates by other jets (h, Z, W, b, etc.) are also presented.

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.

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

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.

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.

Some decays of neutral Higgs bosons in the NMSSM

International Nuclear Information System (INIS)

Cuong, Nguyen Chinh; Trang, Do Thi Thu; Thuy, Nguyen Thi Phuong

2014-01-01

To solve the μ problem of the Minimal Supersymmetric Standard Model (MSSM), a single field S is added to build the Next Minimal Supersymmetric Standard Model (NMSSM). Vacuum enlarged with non-zero vevs of the neutral-even CP is the combination of H u , H d and S. In the NMSSM, the higgs sector is increased to 7 higgs (compared with 5 higgs in the MSSM), including three higgs which are even-CP h 1,2,3 (m h1 < m h2 < m h3 ), two higgs which are odd-CP a 1,2 (m a1 < m a2 ) and a couple of charged higgs H ± . The decays higgs into higgs is one of the remarkable new points of the NMSSM. In this paper we study some decays of neutral Higgs bosons. The numerical results are also presented together with evaluations.

Higgs particles in the standard model and supersymmetric theories

International Nuclear Information System (INIS)

Muehlleitner, M.M.

2000-08-01

This thesis presents a theoretical analysis of the properties of the Higgs bosons in the standard model (SM) and the minimal supersymmetric extension (MSSM), which can be investigated at the LHC and e + e - linear colliders. The final goal is the reconstruction of the Higgs potential and thus the verification of the Higgs mechanism. MSSM Higgs boson production processes at future γγ colliders are calculated in several decay channels. Heavy scalar and pseudoscalar Higgs bosons can be discovered in the bb final state in the investigated mass range 200 to 800 GeV for moderate and large values of tanβ. The τ + τ - channel provides a heavy Higgs boson discovery potential for large values of tanβ. Several mechanisms that can be exploited at e + e - linear colliders for the measurement of the lifetime of a SM Higgs boson in the intermediate mass range are analysed. In the WW mode, the lifetime of Higgs scalars with masses below ∝160 GeV can be determined with an error less than 10%. The reconstruction of the Higgs potential requires the measurement of the Higgs self-couplings. The SM and MSSM trilinear Higgs self-couplings are accessible in double and triple Higgs production. A theoretical analysis is presented in the relevant channels at the LHC and e + e - linear colliders. For high luminosities, the SM trilinear Higgs self-coupling can be measured with an accuracy of 20% at a 500 GeV e + e - linear collider. The MSSM coupling among three light Higgs bosons has to be extracted from continuum production. The other trilinear Higgs couplings are measurable in a restricted range of the MSSM parameter space. At the LHC, the Hhh coupling can be probed in resonant decays. (orig.)

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.

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.

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.)

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.)

NLO corrections to differential cross sections for pseudo-scalar Higgs boson production

International Nuclear Information System (INIS)

Field, B.; Smith, J.; Tejeda-Yeomans, M.E.; Neerven, W.L. van

2003-01-01

We have computed the full next-to-leading (NLO) QCD corrections to the differential distributions d 2 σ/(dp T dy) for pseudo-scalar Higgs (A) production at large hadron colliders. This calculation has been carried out using the effective Lagrangian approach which is valid as long as the mass of the pseudo-scalar Higgs boson m A and its transverse momentum p T do not exceed the top-quark mass m t . The shape of the distributions hardly differ from those obtained for scalar Higgs (H) production because, apart from the overall coupling constant and mass, there are only small differences between the partonic differential distributions for scalar and pseudo-scalar production. Therefore, there are only differences in the magnitudes of the hadronic differential distributions which can be mainly attributed to the unknown mixing angle β describing the pseudo-scalar Higgs coupling to the top quarks

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.

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.

The problem with false vacuum Higgs inflation

International Nuclear Information System (INIS)

Fairbairn, Malcolm; Grothaus, Philipp; Hogan, Robert

2014-01-01

We investigate the possibility of using the only known fundamental scalar, the Higgs, as an inflaton with minimal coupling to gravity. The peculiar appearance of a plateau or a false vacuum in the renormalised effective scalar potential suggests that the Higgs might drive inflation. For the case of a false vacuum we use an additional singlet scalar field, motivated by the strong CP problem, and its coupling to the Higgs to lift the barrier allowing for a graceful exit from inflation by mimicking hybrid inflation. We find that this scenario is incompatible with current measurements of the Higgs mass and the QCD coupling constant and conclude that the Higgs can only be the inflaton in more complicated scenarios

Supersymmetric Higgs bosons and beyond

International Nuclear Information System (INIS)

Carena, Marcela; Kong, Kyoungchul; Ponton, Eduardo; Zurita, Jose

2010-01-01

We consider supersymmetric models that include particles beyond the minimal supersymmetric standard model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest CP-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the standard model and the MSSM.

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...

Associated central exclusive production of charged Higgs bosons

International Nuclear Information System (INIS)

Enberg, Rikard; Pasechnik, Roman

2011-01-01

We propose central exclusive production of a charged Higgs boson in association with a W boson as a possible signature of certain types of extended Higgs sectors. We calculate the cross section and find that the rate at the LHC could be large enough to allow observation in some models with two-Higgs doublets, where the charged Higgs and at least one of the neutral scalars can be light enough. We use the two-Higgs doublet model as a prototype and consider two distinct regions of parameter space, but we also briefly discuss the prospects for the next-to-minimal supersymmetric standard model, where the charged Higgs may very well be quite light.

Goldstone and Higgs Hydrodynamics in the BCS–BEC Crossover

Directory of Open Access Journals (Sweden)

Luca Salasnich

2017-06-01

Full Text Available We discuss the derivation of a low-energy effective field theory of phase (Goldstone and amplitude (Higgs modes of the pairing field from a microscopic theory of attractive fermions. The coupled equations for Goldstone and Higgs fields are critically analyzed in the Bardeen–Cooper–Schrieffer (BCS-to-Bose–Einstein condensate (BEC crossover—both in three spatial dimensions and in two spatial dimensions. The crucial role of pair fluctuations is investigated, and the beyond-mean-field Gaussian theory of the BCS–BEC crossover is compared with available experimental data of the two-dimensional ultracold Fermi superfluid.

High Mass Standard Model Higgs searches at the Tevatron

Directory of Open Access Journals (Sweden)

Petridis Konstantinos A.

2012-06-01

Full Text Available We present the results of searches for the Standard Model Higgs boson decaying predominantly to W+W− pairs, at a center-of-mass energy of √s = 1.96 TeV, using up to 8.2 fb−1 of data collected with the CDF and D0 detectors at the Fermilab Tevatron collider. The analysis techniques and the various channels considered are discussed. These searches result in exclusions across the Higgs mass range of 156.5< mH <173.7 GeV for CDF and 161< mH <170 GeV for D0.

Doubling down on naturalness with a supersymmetric twin Higgs

Science.gov (United States)

Craig, Nathaniel; Howe, Kiel

2014-03-01

We show that naturalness of the weak scale can be comfortably reconciled with both LHC null results and observed Higgs properties provided the double protection of supersymmetry and the twin Higgs mechanism. This double protection radically alters conventional signs of naturalness at the LHC while respecting gauge coupling unification and precision electroweak limits. We find the measured Higgs mass, couplings, and percent-level naturalness of the weak scale are compatible with stops at ~ 3.5 TeV and higgsinos at ~ 1 TeV. The primary signs of naturalness in this scenario include modifications of Higgs couplings, a modest invisible Higgs width, resonant Higgs pair production, and an invisibly-decaying heavy Higgs.

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.

Disentangling Higgs-top couplings in associated production

International Nuclear Information System (INIS)

Ellis, John; Hwang, Dae Sung; Sakurai, Kazuki; Takeuchi, Michihisa

2014-01-01

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, κ t and κ-tilde t , which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-γ-γ couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints on κ-tilde t , if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributions. We discuss methods to measure directly the scalar and pseudoscalar Higgs-top couplings by measurements of Higgs production in association with t-macront, single t and single t-macron at the LHC. Measurements of the total cross sections are very sensitive to variations in the Higgs-top couplings that are consistent with the present indirect constraints, as are invariant mass distributions in t-macrontH, tH and t-macronH final states. We also investigate the additional information on κ t and κ-tilde t that could be obtained from measurements of the longitudinal and transverse t polarization in the different associated production channels, and the t-macront spin correlation in t-macrontH events

Detection of Higgs bosons decaying to bottom quarks

International Nuclear Information System (INIS)

Gilman, F.J.; Price, L.E.

1986-11-01

Several developments affecting the possibility of Higgs detection are discussed. These include the level of certainty about the t quark mass, Monte Carlo programs to generate both signal and background events, and separation and/or enhancement of heavy quark jets from jets due to light quarks or gluons, and the possibility that the neutral Higgs decay into bottom quarks might be the decay mode of choice for detecting the intermediate mass Higgs. Possible means of detection of an intermediate mass Higgs at the SSC, particularly if a prominent decay mode is to bottom quarks, are examined, using the PYTHIA Monte Carlo program to generate both signal and background events. For the signal, events were generated in which Higgs bosons are created in proton-proton collisions, with the Higgs decaying into bottom quarks. The presence of W or Z bosons, created in the same proton-proton collision, is used to enhance the likelihood of Higgs production and to reduce the potentially enormous background. It is found that the Higgs decay to bottom quarks, if important, would be more favorable for detection of the Higgs than decay to top quarks was found to be because of the smaller background. 3 refs., 4 figs

Pseudo-Goldstone Higgs Doublets from Non-Vectorlike Grand Unified Higgs Sector

CERN Document Server

Hernández, A E Cárcamo

2016-01-01

We present a novel way of realizing the pseudo-Nambu-Goldstone boson mechanism for the doublet-triplet splitting in supersymmetric grand unified theories. The global symmetries of the Higgs sector are attributed to a non-vectorlike Higgs content, which is consistent with unbroken supersymmetry in a scenario with flat extra dimensions and branes. We also show how in such a model one can naturally obtain a realistic pattern for the Standard Model fermion masses and mixings.

Higgs production and decay in models of a warped extra dimension with a bulk Higgs

International Nuclear Information System (INIS)

Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias

2015-01-01

Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS 5 space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the H → γγ decay rate and show that they are finite (at one-loop order) as a consequence of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model scalars is constructed in detail. The largest effects are due to virtual KK fermions, whose contributions to the cross section and decay rate introduce a quadratic sensitivity to the maximum allowed value y * of the random complex entries of the 5D anarchic Yukawa matrices. We find an enhancement of the gluon-fusion cross section and a reduction of the H → γγ rate as well as of the tree-level Higgs couplings to fermions and electroweak gauge bosons. As a result, we perform a detailed study of the correlated signal strengths for different production mechanisms and decay channels as functions of y * , the mass scale of Kaluza-Klein resonances and the scaling dimension of the composite Higgs operator

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.

Higgs portal valleys, stability and inflation

CERN Document Server

Ballesteros, Guillermo

2015-01-01

The measured values of the Higgs and top quark masses imply that the Standard Model potential is very likely to be unstable at large Higgs values. This is particularly problematic during inflation, which sources large perturbations of the Higgs. The instability could be cured by a threshold effect induced by a scalar with a large vacuum expectation value and directly connected to the Standard Model through a Higgs portal coupling. However, we find that in a minimal model in which the scalar generates inflation, this mechanism does not stabilize the potential because the mass required for inflation is beyond the instability scale. This conclusion does not change if the Higgs has a direct weak coupling to the scalar curvature. On the other hand, if the potential is absolutely stable, successful inflation in agreement with current CMB data can occur along a valley of the potential with a Mexican hat profile. We revisit the stability conditions, independently of inflation, and clarify that the threshold effect ca...

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, ...

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."

Higgs enhancement for the dark matter relic density

Science.gov (United States)

Harz, Julia; Petraki, Kalliopi

2018-04-01

We consider the long-range effect of the Higgs on the density of thermal-relic dark matter. While the electroweak gauge boson and gluon exchange have been previously studied, the Higgs is typically thought to mediate only contact interactions. We show that the Sommerfeld enhancement due to a 125 GeV Higgs can deplete TeV-scale dark matter significantly and describe how the interplay between the Higgs and other mediators influences this effect. We discuss the importance of the Higgs enhancement in the minimal supersymmetric standard model and its implications for experiments.

Higgs boson pair production at the photon linear collider in the two Higgs doublet model

International Nuclear Information System (INIS)

Asakawa, Eri; Harada, Daisuke; Okada, Yasuhiro; Kanemura, Shinya; Tsumura, Koji

2009-02-01

We calculate the cross section of the lightest Higgs boson pair production at the Photon Linear Collider in the two Higgs doublet model. We focus on the scenario in which the lightest Higgs boson has the standard model like couplings to gauge bosons. We take into account the one-loop correction to the hhh coupling as well as additional one-loop diagrams due to charged bosons to the γγ → hh helicity amplitudes. We discuss the impact of these corrections on the hhh coupling measurement at the Photon Linear Collider. (author)

Goldstone bosons and a dynamical Higgs field

NARCIS (Netherlands)

Mooij, S.; Postma, M.

2011-01-01

Higgs inflation uses the gauge variant Higgs field as the inflaton. During inflation the Higgs field is displaced from its minimum, which results in associated Goldstone bosons that are apparently massive. Working in a minimally coupled U(1) toy model, we use the closed-time-path formalism to show

Doubling down on naturalness with a supersymmetric twin Higgs

International Nuclear Information System (INIS)

Craig, Nathaniel; Howe, Kiel

2014-01-01

We show that naturalness of the weak scale can be comfortably reconciled with both LHC null results and observed Higgs properties provided the double protection of supersymmetry and the twin Higgs mechanism. This double protection radically alters conventional signs of naturalness at the LHC while respecting gauge coupling unification and precision electroweak limits. We find the measured Higgs mass, couplings, and percent-level naturalness of the weak scale are compatible with stops at ∼3.5 TeV and higgsinos at ∼1 TeV. The primary signs of naturalness in this scenario include modifications of Higgs couplings, a modest invisible Higgs width, resonant Higgs pair production, and an invisibly-decaying heavy Higgs

Higgs decays to dark matter: Beyond the minimal model

International Nuclear Information System (INIS)

Pospelov, Maxim; Ritz, Adam

2011-01-01

We examine the interplay between Higgs mediation of dark-matter annihilation and scattering on one hand and the invisible Higgs decay width on the other, in a generic class of models utilizing the Higgs portal. We find that, while the invisible width of the Higgs to dark matter is now constrained for a minimal singlet scalar dark matter particle by experiments such as XENON100, this conclusion is not robust within more generic examples of Higgs mediation. We present a survey of simple dark matter scenarios with m DM h /2 and Higgs portal mediation, where direct-detection signatures are suppressed, while the Higgs width is still dominated by decays to dark matter.

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.)

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.)

Partially composite Goldstone Higgs boson

DEFF Research Database (Denmark)

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

2017-01-01

We consider a model of dynamical electroweak symmetry breaking with a partially composite Goldstone Higgs boson. The model is based on a strongly interacting fermionic sector coupled to a fundamental scalar sector via Yukawa interactions. The SU(4)×SU(4) global symmetry of these two sectors...... is broken to a single SU(4) via Yukawa interactions. Electroweak symmetry breaking is dynamically induced by condensation due to the strong interactions in the new fermionic sector which further breaks the global symmetry SU(4)→Sp(4). The Higgs boson arises as a partially composite state which is an exact...... Goldstone boson in the limit where SM interactions are turned off. Terms breaking the SU(4) global symmetry explicitly generate a mass for the Goldstone Higgs boson. The model realizes in different limits both (partially) composite Higgs and (bosonic) technicolor models, thereby providing a convenient...

The Higgs of the Higgs and the diphoton channel

CERN Document Server

Kannike, Kristjan

2016-07-20

LHC results do not confirm conventional natural solutions to the Higgs mass hierarchy problem, motivating alternative interpretations where a hierarchically small weak scale is generated from a dimension-less quantum dynamics. We propose weakly and strongly-coupled models where the field that breaks classical scale invariance giving mass to itself and to the Higgs is identified with a possible new resonance within the LHC reach. As an example, we identify such resonance with the 750 GeV diphoton excess recently reported by ATLAS and CMS. Such models can be extrapolated up to the Planck scale, provide Dark Matter candidates and eliminate the SM vacuum instability.

Higgs detectability in the extended supersymmetric standard model

International Nuclear Information System (INIS)

Kamoshita, Jun-ichi

1995-01-01

Higgs detectability at a future linear collider are discussed in the minimal supersymmetric standard model (MSSM) and a supersymmetric standard model with a gauge singlet Higgs field (NMSSM). First, in the MSSM at least one of the neutral scalar Higgs is shown to be detectable irrespective of parameters of the model in a future e + e - linear collider at √s = 300-500 GeV. Next the Higgs sector of the NMSSM is considered, since the lightest Higgs boson can be singlet dominated and therefore decouple from Z 0 boson it is important to consider the production of heavier Higgses. It is shown that also in this case at least one of the neutral scalar Higgs will be detectable in a future linear collider. We extend the analysis and show that the same is true even if three singlets are included. Thus the detectability of these Higgs bosons of these models is guaranteed. (author)

Large Higgs energy region in Higgs associated top pair production at the Linear Collider

International Nuclear Information System (INIS)

Farrell, Cailin; Hoang, Andre H.

2005-01-01

The process e + e - →ttH is considered in the kinematic end point region where the Higgs energy is close to its maximal energy. In perturbative QCD, using the loop expansion, the amplitudes are plagued by Coulomb singularities that need to be resummed. We show that the QCD dynamics in this end point region is governed by nonrelativistic heavy quarkonium dynamics, and we use a nonrelativistic effective theory to compute the Higgs energy distribution at leading and next-to-leading-logarithmic approximation in the nonrelativistic expansion. Updated numbers for the total cross section including the summations in the Higgs energy end point region are presented

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.

Higgs constraints from vector boson fusion and scattering

International Nuclear Information System (INIS)

Campbell, John M.; Ellis, R. Keith

2015-01-01

We present results on 4-lepton + 2-jet production, the partonic processes most commonly described as vector boson pair production in the Vector Boson Fusion (VBF) mode. That final state contains diagrams that are mediated by Higgs boson exchange. We focus particularly on the high-mass behaviour of the Higgs boson mediated diagrams, which unlike on-shell production, gives information about the Higgs couplings without assumptions on the Higgs boson total width. We assess the sensitivity of the high-mass region to Higgs coupling strengths, considering all vector boson pair channels, W - W + , W ± W ± , W ± Z and ZZ. Because of the small background, the most promising mode is W + W + which has sensitivity to Higgs couplings because of Higgs boson exchange in the t-channel. Furthermore, using the Caola-Melnikov (CM) method, the off-shell couplings can be interpreted as bounds on the Higgs boson total width. We estimate the bound that can be obtained with current data, as well as the bounds that could be obtained at √s=13 TeV in the VBF channel for data samples of 100 and 300 fb -1 . The CM method has already been successfully applied in the gluon fusion (GGF) production channel. The VBF production channel gives important complementary information, because both production and decay of the Higgs boson occur already at tree graph level

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

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

Constraints on the Lee-Wick Higgs sector

International Nuclear Information System (INIS)

Carone, Christopher D.; Primulando, Reinard

2009-01-01

Lee-Wick partners to the standard model Higgs doublet may appear at a mass scale that is significantly lower than that of the remaining Lee-Wick partner states. The relevant effective theory is a two-Higgs doublet model in which one doublet has wrong-sign kinetic and mass terms. We determine bounds on this effective theory, including those from neutral B-meson mixing, b→X s γ, and Z→bb. The results differ from those of conventional two-Higgs doublet models and lead to meaningful constraints on the Lee-Wick Higgs sector.

Disentangling Higgs-top couplings in associated production

Energy Technology Data Exchange (ETDEWEB)

Ellis, John [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,London WC2R 2LS (United Kingdom); TH Division, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Hwang, Dae Sung [Department of Physics, Sejong University,Seoul 143-747 (Korea, Republic of); Sakurai, Kazuki; Takeuchi, Michihisa [Theoretical Particle Physics and Cosmology Group, Physics Department, King’s College London,London WC2R 2LS (United Kingdom)

2014-04-01

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, κ{sub t} and κ-tilde{sub t}, which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-γ-γ couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints on κ-tilde{sub t}, if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributions. We discuss methods to measure directly the scalar and pseudoscalar Higgs-top couplings by measurements of Higgs production in association with t-macront, single t and single t-macron at the LHC. Measurements of the total cross sections are very sensitive to variations in the Higgs-top couplings that are consistent with the present indirect constraints, as are invariant mass distributions in t-macrontH, tH and t-macronH final states. We also investigate the additional information on κ{sub t} and κ-tilde{sub t} that could be obtained from measurements of the longitudinal and transverse t polarization in the different associated production channels, and the t-macront spin correlation in t-macrontH events.

Discovering Higgs Bosons of the MSSM using Jet Substructure

International Nuclear Information System (INIS)

Kribs, Graham D.; Martin, Adam; Roy, Tuhin S.; Spannowsky, Michael

2010-01-01

We present a qualitatively new approach to discover Higgs bosons of the MSSM at the LHC using jet substructure techniques applied to boosted Higgs decays. These techniques are ideally suited to the MSSM, since the lightest Higgs boson overwhelmingly decays to b(bar b) throughout the entire parameter space, while the heavier neutral Higgs bosons, if light enough to be produced in a cascade, also predominantly decay to b(bar b). The Higgs production we consider arises from superpartner production where superpartners cascade decay into Higgs bosons. We study this mode of Higgs production for several superpartner hierarchies: m # tilde q#,m # tilde g# > m # tilde W#, # tilde B# > m h + μ; m(tilde q);m # tilde q#,m # tilde g# > m # tilde W#, # tilde B# > m h,H,A + μ; and m # tilde q#,m # tilde g# > m # tilde W# > m h + μ with m # tilde B# ∼ μ. In these cascades, the Higgs bosons are boosted, with pT > 200 GeV a large fraction of the time. Since Higgs bosons appear in cascades originating from squarks and/or gluinos, the cross section for events with at least one Higgs boson can be the same order as squark/gluino production. Given 10 fb -1 of 14 TeV LHC data, with m # tilde q# ∼< 1 TeV, and one of the above superpartner mass hierarchies, our estimate of S√ B of the Higgs signal is sufficiently high that the b(bar b) mode can become the discovery mode of the lightest Higgs boson of the MSSM.

Ruling out a strongly interacting standard Higgs model

International Nuclear Information System (INIS)

Riesselmann, K.; Willenbrock, S.

1997-01-01

Previous work has suggested that perturbation theory is unreliable for Higgs- and Goldstone-boson scattering, at energies above the Higgs-boson mass, for relatively small values of the Higgs quartic coupling λ(μ). By performing a summation of nonlogarithmic terms, we show that perturbation theory is in fact reliable up to relatively large coupling. This eliminates the possibility of a strongly interacting standard Higgs model at energies above the Higgs-boson mass, complementing earlier studies which excluded strong interactions at energies near the Higgs-boson mass. The summation can be formulated in terms of an appropriate scale in the running coupling, μ=√(s)/e∼√(s)/2.7, so it can be incorporated easily in renormalization-group-improved tree-level amplitudes as well as higher-order calculations. copyright 1996 The American Physical Society

Limits from LEP Data on CP-Violating Nonminimal Higgs Sectors

International Nuclear Information System (INIS)

Gunion, J.F.; Grzadkowski, B.; Kalinowski, J.; Haber, H.E.; Kalinowski, J.

1997-01-01

We derive a sum rule which shows how to extend limits from LEP data on the masses of the lightest CP-even and CP-odd Higgs bosons of a CP-conserving two-Higgs doublet model to any two Higgs bosons of a general CP-violating two-Higgs-doublet model. We generalize the analysis to a Higgs sector consisting of an arbitrary number of Higgs doublets and singlets, giving explicit limits for the CP-conserving and CP-violating two-doublet plus one-singlet Higgs sectors. copyright 1997 The American Physical Society

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 ...

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.

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.

Baryonic Higgs at the LHC

Energy Technology Data Exchange (ETDEWEB)

Duerr, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fileviez Perez, Pavel [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, Physics Dept.; Smirnov, Juri [INFN, Sezione di Firenze (Italy); Florence Univ., Sesto Fiorentino (Italy). Dept. of Physics and Astronomy

2017-04-15

We investigate the possible collider signatures of a new Higgs in simple extensions of the Standard Model where baryon number is a local symmetry spontaneously broken at the low scale. We refer to this new Higgs as ''Baryonic Higgs''. This Higgs has peculiar properties since it can decay into all Standard Model particles, the leptophobic gauge boson, and the vector-like quarks present in these theories to ensure anomaly cancellation. We investigate in detail the constraints from the γγ, Zγ, ZZ, and WW searches at the Large Hadron Collider, needed to find a lower bound on the scale at which baryon number is spontaneously broken. The di-photon channel turns out to be a very sensitive probe in the case of small scalar mixing and can severely constrain the baryonic scale. We also study the properties of the leptophobic gauge boson in order to understand the testability of these theories at the LHC.

Higgs mass determination in supersymmetry

Energy Technology Data Exchange (ETDEWEB)

Vega, Javier Pardo [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy); SISSA International School for Advanced Studies and INFN Trieste, Via Bonomea 265, 34136, Trieste (Italy); Villadoro, Giovanni [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy)

2015-07-29

We present the state-of-the-art of the effective field theory computation of the MSSM Higgs mass, improving the existing ones by including extra threshold corrections. We show that, with this approach, the theoretical uncertainty is within 1 GeV in most of the relevant parameter space. We confirm the smaller value of the Higgs mass found in the EFT computations, which implies a slightly heavier SUSY scale. We study the large tan β region, finding that sbottom thresholds might relax the upper bound on the scale of SUSY. We present SUSYHD, a fast computer code that computes the Higgs mass and its uncertainty for any SUSY scale, from the TeV to the Planck scale, even in Split SUSY, both in the (DR)-bar and in the on-shell schemes. Finally, we apply our results to derive bounds on some well motivated SUSY models, in particular we show how the value of the Higgs mass allows to determine the complete spectrum in minimal gauge mediation.

Frequently Asked Questions: The Higgs!

CERN Multimedia

CERN Bulletin

2012-01-01

Why have we tried so hard to find the Higgs particle? How does the Higgs mechanism work? What is the difference in physics between strong evidence and a discovery? Why do physicists speak in terms of "sigmas"? Find out here!   Why have we tried so hard to find the Higgs particle? Because it could be the answer to the question: how does Nature decide whether or not to assign mass to particles? All the fundamental particles making up matter – the electron, the quarks, etc. – have masses. Moreover, quantum physics requires that forces are also carried by particles. The W and Z particles that carry the weak force responsible for radioactivity must also have masses, whereas the photon, the carrier of the electromagnetic force, has no mass at all. This is the root of the “Higgs problem”: how to give masses to the fundamental particles and break the symmetry between the massive W and Z and the massless photon? Just assigning masses by hand...

Impersonating the Standard Model Higgs boson: alignment without decoupling

International Nuclear Information System (INIS)

Carena, Marcela; Low, Ian; Shah, Nausheen R.; Wagner, Carlos E.M.

2014-01-01

In models with an extended Higgs sector there exists an alignment limit, in which the lightest CP-even Higgs boson mimics the Standard Model Higgs. The alignment limit is commonly associated with the decoupling limit, where all non-standard scalars are significantly heavier than the Z boson. However, alignment can occur irrespective of the mass scale of the rest of the Higgs sector. In this work we discuss the general conditions that lead to “alignment without decoupling”, therefore allowing for the existence of additional non-standard Higgs bosons at the weak scale. The values of tan β for which this happens are derived in terms of the effective Higgs quartic couplings in general two-Higgs-doublet models as well as in supersymmetric theories, including the MSSM and the NMSSM. Moreover, we study the information encoded in the variations of the SM Higgs-fermion couplings to explore regions in the m A −tan β parameter space

A Study Of Observability Of Higgs Boson Decay In Higgs Boson Decays To Two Z Mesons Decays To Four Leptons At Cms

CERN Document Server

Liang, G

2005-01-01

The Standard Model (SM) of particle physics has been the most successful theory about fundamental particles and how they interact. In SM, the originally massless fundamental particles acquire masses in a process called the Higgs mechanism. This mechanism involves an additional particle, called the Higgs boson, whose responsibility is to break the electroweak symmetry and help those massless particles acquire masses. With the discovery of the top quark at Tevatron in 1995, the Higgs boson remains to be the only unfound fundamental particle in the Standard Model. The discovery of the Higgs boson would greatly increase our understanding of the origin of the mass. One of the most important objectives of the LHC experiment is to discover the Higgs boson. At LHC, the CMS experiment is optimized for the search of the Higgs boson over a mass range up to 1 TeV. Among all Higgs decay channels, H → ZZ → 4l is one of the most promising channels to search the SM Higgs boson at CMS. This study concentrat...

Signatures of Higgs dilaton and critical Higgs inflation.

Science.gov (United States)

García-Bellido, Juan

2018-03-06

We test the Higgs dilaton inflation model (HDM) using the latest cosmological datasets, including the cosmic microwave background temperature, polarization and lensing data from the Planck satellite (2015), the BICEP and Keck Array experiments, the type Ia supernovae from the JLA catalogue, the baryon acoustic oscillations from CMASS, LOWZ and 6dF, the weak lensing data from the CFHTLenS survey and the matter power spectrum measurements from the latest SDSS data release. We find that the values of all cosmological parameters allowed by the HDM are well within the Planck satellite (2015) constraints. In particular, we determine [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] (at 95.5% c.l.). We also place new stringent constraints on the couplings of the HDM, ξ χ Higgs inflation model, taking into account the running of both the self-coupling λ( μ ) and the non-minimal coupling to gravity ξ ( μ ). We find peaks in the curvature power spectrum at scales corresponding to the critical value μ that re-enter during the radiation era and collapse to form a broad distribution of clustered primordial black holes, which could constitute today the main component of dark matter.This article is part of the Theo Murphy meeting issue 'Higgs cosmology'. © 2018 The Author(s).

Introduction to the physics of Higgs bosons

International Nuclear Information System (INIS)

Dawson, S.

1994-11-01

A basic introduction to the physics of the Standard Model Higgs boson is given. We discuss Higgs boson production in e + e - and hadronic collisions and survey search techniques at future accelerators. The Higgs bosons of the minimal SUSY model are briefly considered. Indirect limits from triviality arguments, vacuum stability and precision measurements at LEP are also presented

Gaugephobic Higgs Signals at the LHC

CERN Document Server

Galloway, Jamison; McRaven, John; Terning, John

2009-01-01

The Gaugephobic Higgs model provides an interpolation between three different models of electroweak symmetry breaking: Higgsless models, Randall-Sundrum models, and the Standard Model. At parameter points between the extremes, Standard Model Higgs signals are present at reduced rates, and Higgsless Kaluza-Klein excitations are present with shifted masses and couplings, as well as signals from exotic quarks necessary to protect the Zbb coupling. Using a new implementation of the model in SHERPA, we show the LHC signals which differentiate the generic Gaugephobic Higgs model from its limiting cases. These are all signals involving a Higgs coupling to a Kaluza-Klein gauge boson or quark. We identify the clean signal $p p \\to W^(i) \\to W H$ mediated by a Kaluza-Klein W, which can be present at large rates and is enhanced for even Kaluza-Klein numbers. Due to the very hard lepton coming from the W decay, this signature has little background, and provides a better discovery channel for the Higgs than any of the Sta...

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

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

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.

NNLO QCD corrections to Higgs boson production at large transverse momentum

Energy Technology Data Exchange (ETDEWEB)

Chen, X. [Center for High Energy Physics, Peking University,Beijing 100871 (China); Cruz-Martinez, J. [Institute for Particle Physics Phenomenology, Department of Physics, University of Durham,Durham, DH1 3LE (United Kingdom); Gehrmann, T. [Department of Physics, University of Zürich,CH-8057 Zürich (Switzerland); Glover, E.W.N. [Institute for Particle Physics Phenomenology, Department of Physics, University of Durham,Durham, DH1 3LE (United Kingdom); Jaquier, M. [Albert-Ludwigs-Universität Freiburg, Physikalisches Institut,D-79104 Freiburg (Germany)

2016-10-13

We derive the second-order QCD corrections to the production of a Higgs boson recoiling against a parton with finite transverse momentum, working in the effective field theory in which the top quark contributions are integrated out. To account for quark mass effects, we supplement the effective field theory result by the full quark mass dependence at leading order. Our calculation is fully differential in the final state kinematics and includes the decay of the Higgs boson to a photon pair. It allows one to make next-to-next-to-leading order (NNLO)-accurate theory predictions for Higgs-plus-jet final states and for the transverse momentum distribution of the Higgs boson, accounting for the experimental definition of the fiducial cross sections. The NNLO QCD corrections are found to be moderate and positive, they lead to a substantial reduction of the theory uncertainty on the predictions. We compare our results to 8 TeV LHC data from ATLAS and CMS. While the shape of the data is well-described for both experiments, we agree on the normalization only for CMS. By normalizing data and theory to the inclusive fiducial cross section for Higgs production, good agreement is found for both experiments, however at the expense of an increased theory uncertainty. We make predictions for Higgs production observables at the 13 TeV LHC, which are in good agreement with recent ATLAS data. At this energy, the leading order mass corrections to the effective field theory prediction become significant at large transverse momenta, and we discuss the resulting uncertainties on the predictions.

NNLO QCD corrections to Higgs boson production at large transverse momentum

Science.gov (United States)

Chen, X.; Cruz-Martinez, J.; Gehrmann, T.; Glover, E. W. N.; Jaquier, M.

2016-10-01

We derive the second-order QCD corrections to the production of a Higgs boson recoiling against a parton with finite transverse momentum, working in the effective field theory in which the top quark contributions are integrated out. To account for quark mass effects, we supplement the effective field theory result by the full quark mass dependence at leading order. Our calculation is fully differential in the final state kinematics and includes the decay of the Higgs boson to a photon pair. It allows one to make next-to-next-to-leading order (NNLO)-accurate theory predictions for Higgs-plus-jet final states and for the transverse momentum distribution of the Higgs boson, accounting for the experimental definition of the fiducial cross sections. The NNLO QCD corrections are found to be moderate and positive, they lead to a substantial reduction of the theory uncertainty on the predictions. We compare our results to 8 TeV LHC data from ATLAS and CMS. While the shape of the data is well-described for both experiments, we agree on the normalization only for CMS. By normalizing data and theory to the inclusive fiducial cross section for Higgs production, good agreement is found for both experiments, however at the expense of an increased theory uncertainty. We make predictions for Higgs production observables at the 13 TeV LHC, which are in good agreement with recent ATLAS data. At this energy, the leading order mass corrections to the effective field theory prediction become significant at large transverse momenta, and we discuss the resulting uncertainties on the predictions.

Triple top signal as a probe of charged Higgs in a 2HDM

Science.gov (United States)

Patrick, Riley; Sharma, Pankaj; Williams, Anthony G.

2018-05-01

Within the framework of the type-II Two Higgs Doublet Model (2HDM-II) we study the production of three top quarks at the Large Hadron Collider (LHC). In the Standard Model the production cross section of three tops is low (≈3 fb), while it is expected to be significant in the 2HDM-II for reasonable choices of the parameters. We study the production of a charged Higgs in association with a top quark, followed by the decays H± →W± A and A → t t bar . We undertake a full detector simulation of the signal, and use simple conservative cuts, focussing on the final states that contain three or more leptons, and exactly one same sign di-lepton pair. Finally, we present the exclusion bounds dependent on charged Higgs and pseudoscalar Higgs masses expected in the near future at the 14 TeV LHC.

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.

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.

Standard model Higgs boson-inflaton and dark matter

International Nuclear Information System (INIS)

Clark, T. E.; Liu Boyang; Love, S. T.; Veldhuis, T. ter

2009-01-01

The standard model Higgs boson can serve as the inflaton field of slow roll inflationary models provided it exhibits a large nonminimal coupling with the gravitational scalar curvature. The Higgs boson self interactions and its couplings with a standard model singlet scalar serving as the source of dark matter are then subject to cosmological constraints. These bounds, which can be more stringent than those arising from vacuum stability and perturbative triviality alone, still allow values for the Higgs boson mass which should be accessible at the LHC. As the Higgs boson coupling to the dark matter strengthens, lower values of the Higgs boson mass consistent with the cosmological data are allowed.

Higgs-Mediated Electric Dipole Moments in the MSSM An Application to Baryogenesis and Higgs Searches

CERN Document Server

Pilaftsis, Apostolos

2002-01-01

We perform a comprehensive study of the dominant two- and higher-loop contributions to the Tl(205), neutron and muon electric dipole moments induced by Higgs bosons, third-generation quarks and squarks, charginos and gluinos in the Minimal Supersymmetric Standard Model (MSSM). We find that strong correlations exist among the contributing CP-violating operators, for large stop, gluino and chargino phases, and for a wide range of values of \\tan\\beta and charged Higgs-boson masses, giving rise to large suppressions of the Tl(205) and neutron electric dipole moments below their present experimental limits. Based on this observation, we discuss the constraints that the nonobservation of electric dipole moments imposes on the radiatively-generated CP-violating Higgs sector and on the mechanism of electroweak baryogenesis in the MSSM. We improve previously suggested benchmark scenarios of maximal CP violation for analyzing direct searches of CP-violating MSSM Higgs-bosons at high-energy colliders, and stress the imp...

Search for the standard model Higgs boson decaying to a bb pair in events with no charged leptons and large missing transverse energy using the full CDF data set.

Science.gov (United States)

Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M E; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calamba, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; 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; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chung, W H; Chung, Y S; Ciocci, M A; Clark, A; Clarke, C; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; Dell'Orso, M; Demortier, L; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, S; Ershaidat, N; Eusebi, R; Farrington, S; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kim, Y J; Kimura, N; Kirby, M; Klimenko, S; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; LeCompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Mastrandrea, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Prokoshin, F; Pranko, A; Ptohos, F; Punzi, G; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Sorin, V; Song, H; Squillacioti, P; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; 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; Zanetti, A; Zeng, Y; Zhou, C; Zucchelli, S

2012-09-14

We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at sqrt[s]=1.96  TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45  fb(-1). We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a b quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and 150  GeV/c(2). For a Higgs boson mass of 125  GeV/c(2), the observed (expected) limit is 6.7 (3.6) times the standard model prediction.

Flavor with a light dynamical "Higgs particle"

CERN Document Server

Alonso, R.; Merlo, L.; Rigolin, S.; Yepes, J.

2013-01-01

The Higgs-fermion couplings are sensitive probes of possible new physics behind a stable light Higgs particle. It is then essential to identify the flavour pattern of those interactions. We consider the case in which a strong dynamics lies behind a light Higgs, and explore the implications within the Minimal Flavour Violation ansatz. The dominant effects on flavour-changing Higgs-fermion couplings stem in this context from operators with mass dimension <6, and we analyze all relevant chiral operators up to that order, including loop-corrections induced by 4-dimensional ones. Bounds on the operator coefficients are derived from a plethora of low-energy flavour transitions, providing a guideline on which flavour-changing Higgs interactions may be open to experimental scrutiny. In particular, the coefficient of a genuinely CP-odd operator is only softly constrained and therefore its impact is potentially interesting.

Higgs bosons in the left-right model

International Nuclear Information System (INIS)

Boyarkina, G.G.; Boyarkin, O.M.

2000-01-01

The model with the SU(2) L x SU(2) R x U(1) B-L gauge group, containing one bidoublet and two triplets in the Higgs sector, is considered. The link between the constants determining the physical Higgs boson interactions and the neutrino oscillation parameters is found. It is shown that the observation of the ultrahigh-energy neutrinos with the help of the processes e - ν e →W - Z, e - ν e →μ - ν μ , gives us information on the singly charged Higgs bosons. The processes of the doubly charged Higgs boson production, e - μ - →Δ (--) 1 γ, e - μ - →Δ (--) 1 Z, are investigated. From the point of view of detecting the neutral Higgs bosons the process of the electron-muon recharge e - μ + →e + μ - is studied. (orig.)

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).

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.

A very light Higgs at LEP

International Nuclear Information System (INIS)

Brown, N.

1990-01-01

If the standard Higgs particle is very light (≤50 MeV) then it will be sufficiently long lived that it could decay outside the detectors at LEP. This could give a signal of two final state leptons which are not back-to-back, with missing transverse momentum. We show that with suitable cuts this Higgs signal can be distinguished from backgrounds with a large enough rate that such a light Higgs will either be discovered or completely ruled out. (author)

The hunt for the Higgs particle

CERN Multimedia

CERN. Geneva

2003-01-01

This series of lectures will cover experimental search strategies for the Higgs boson from LEP to LHC/Tevatron and to a possible e+e- linear collider (NLC). The emphasis will be on specific benchmark decay channels, e.g. H->bb, H->ZZ->4 leptons, H->WW->lvjj, in terms of signal reconstruction and background rejection, on Higgs boson searches in supersymmetric models, and on precise measurements of the Higgs boson properties if it were to be discovered at one of the future machines.

A Brief Survey of Higgs Bundles

OpenAIRE

Zúñiga-Rojas, Ronald Alberto

2018-01-01

Considering a compact Riemann surface of genus greater than two, a Higgs~bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This theory started around thirty years ago, with Hitchin's work, when he reduced the self-duality equations from dimension four to dimension two, and so, studied those equations over Riemann surfaces. Hitchin baptized those fields as "Higgs fields" beacuse in the context of physics and ...

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

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.

Discovering Higgs bosons of the MSSM using jet substructure

International Nuclear Information System (INIS)

Kribs, Graham D.; Roy, Tuhin S.; Spannowsky, Michael; Martin, Adam

2010-01-01

We present a qualitatively new approach to discover Higgs bosons of the minimal supersymmetric standard model (MSSM) at the LHC using jet substructure techniques applied to boosted Higgs decays. These techniques are ideally suited to the MSSM, since the lightest Higgs boson overwhelmingly decays to bb throughout the entire parameter space, while the heavier neutral Higgs bosons, if light enough to be produced in a cascade, also predominantly decay to bb. The Higgs production we consider arises from superpartner production where superpartners cascade decay into Higgs bosons. We study this mode of Higgs production for several superpartner hierarchies: m q -tilde, m g -tilde>m W -tilde ,B -tilde>m h +μ; m q -tilde, m g -tilde>m W -tilde ,B -tilde>m h,H,A +μ; and m q -tilde, m g -tilde>m W -tilde>m h +μ with m B -tilde≅μ. In these cascades, the Higgs bosons are boosted, with p T >200 GeV a large fraction of the time. Since Higgses appear in cascades originating from squarks and/or gluinos, the cross section for events with at least one Higgs can be the same order as squark/gluino production. Given 10 fb -1 of 14 TeV LHC data, with m q -tilde < or approx. 1 TeV, and one of the above superpartner mass hierarchies, our estimate of S/√(B) of the Higgs signal is sufficiently high that the bb mode can become the discovery mode of the lightest Higgs boson of the MSSM.

Measurement of the Higgs boson mass with the ATLAS detector

Directory of Open Access Journals (Sweden)

Garay Walls F. M.

2015-01-01

Full Text Available A summary of the latest results on the combined measurement of the Higgs boson mass in the H → ZZ* → 4l and the H → γγ decay channels with the ATLAS detector is presented. The analysis uses 25 fb−1 of pp collision data recorded by the ATLAS detector at the CERN Large Hadron Collider at centre-of-mass energies of 7TeV and 8 TeV during 2011 and 2012. The combined measured value of the Higgs boson mass is mH = 125.36 ± 0.37 (stat ± 0.18 (syst GeV.

Systematic study of Higgs masses in the MSSM

CERN Document Server

Ghosh, B

2000-01-01

The Higgs masses in the minimal supersymmetric standard model at extremely high energies relevant to LEP2 and LHC have been studied. The results of systematic studies on Higgs masses for the possible ranges of all the parameters in the case of 1-loop radiative correction to the Higgs boson masses have been given. On the basis of detailed analyses we come to interesting constraints on the Higgs masses in the minimal supersymmetric standard model. (11 refs).

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

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.

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\

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

Stiefel-Skyrem-Higgs models, their classical static solutions and Yang-Mills-Higgs monopoles

International Nuclear Information System (INIS)

Dobrev, V.K.

1981-07-01

A new series of models is introduced by adding Higgs fields to the earlier proposed euclidean four-dimensional Skyrme-like models with Yang-Mills composite fields constructed from Stiefel manifold-valued fields. The classical static versions of these models are discussed. The connection with the monopole solutions of the Yang-Mills-Higgs models in the Prasad-Sommerfield limit is pointed out and the BPS monopole is reobtained as an example. (author)

Higgs and new physics at high energy

International Nuclear Information System (INIS)

Solans, C.A.

2014-07-01

The observation of a new particle in the search for the Standard Model (SM) Higgs boson at the LHC, reported by the ATLAS and CMS collaborations, is a milestone in the quest to understand electroweak symmetry breaking. The evidence at the level of 5*σ for a Higgs boson-like particle has been published by both experiments after a preliminary analysis of the data from the LHC Run-I. Precision measurements of the new particle are of critical importance. ATLAS and CMS discovered a Higgs like particle with a mass close to 125.5 GeV, and measured the spin, parity and signal strength to be compatible with the one from the SM Higgs boson [J P = 0 + , μ(VBF+VH)=μ(ggH+ttH)=1]. In a coupling scale factors analysis, compatibility with the SM is found in all the tests performed, with probabilities ranging from 7% to 21%. Consequently, the Higgs physics potential of the LHC Run-I is almost exploited. Run-II and beyond will give the possibility to measure the couplings more precisely, to constrain rare decays further, and to determine a possible CP admixture of the Higgs boson

Alchemical inflation: inflaton turns into Higgs

Science.gov (United States)

Nakayama, Kazunori; Takahashi, Fuminobu

2012-11-01

We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field.

Alchemical inflation: inflaton turns into Higgs

International Nuclear Information System (INIS)

Nakayama, Kazunori; Takahashi, Fuminobu

2012-01-01

We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field

Measuring the Higgs mass at TESLA

International Nuclear Information System (INIS)

Garcia-Abia, P.; Lohmann, W.; Raspereza, A.

2001-01-01

We report on the accuracy of the measurement of the Higgs boson mass that would be achieved in a linear collider operating at a center-of-mass energy of 350 GeV, assuming an integrated luminosity of 500 fb-1. For that we have exploited the exclusive Higgs decays into b quarks and W bosons. The Higgs mass is determined with an accuracy of about 40 MeV for m H =120 GeV and 80 MeV for m H =180 GeV

Probing the non-minimal Higgs sector at the SSC

International Nuclear Information System (INIS)

Gunion, J.F.; Haber, H.E.; Komamiya, S.; Yamamoto, H.; Barbaro-Galtieri, A.

1987-11-01

Non-minimal Higgs sectors occur in the Standard Model with more than one Higgs doublet, as well as in theories that go beyond the Standard Model. In this report, we discuss how Higgs search strategies must be altered, with respect to the Standard Model approaches, in order to probe the non-minimal Higgs sectors at the SSC

CMS presents new boundary of Higgs width

CERN Multimedia

Katarina Anthony

2014-01-01

At last year's Moriond conference, CERN physicists announced the retirement of the "Higgs-like" particle and the arrival of "boson, Higgs boson". Now, one year later, at the same session in the same conference, physicists are back with more exciting news about the famed particle. This time: the best constraint yet of the Higgs Boson “width”, a parameter that determines the particle’s lifetime.   Rencontres de Moriond 2014. As a key indicator for new physics, the Higgs “width” has long been on the LHC "to-do" list. Now less than two years post-discovery, the CMS experiment has gotten the closest yet to pinning it down, constraining the parameter to < 17 MeV with 95% confidence. This result is some two orders of magnitude better than previous limits: stronger evidence that this boson looks like the Standard Model Higgs boson. "It's been exciting to see how wel...

Higgs production via weak boson fusion in the standard model and the MSSM

International Nuclear Information System (INIS)

Figy, Terrance; Palmer, Sophy

2010-12-01

Weak boson fusion is expected to be an important Higgs production channel at the LHC. Complete one-loop results for weak boson fusion in the Standard Model have been obtained by calculating the full virtual electroweak corrections and photon radiation and implementing these results into the public Monte Carlo program VBFNLO (which includes the NLO QCD corrections). Furthermore the dominant supersymmetric one-loop corrections to neutral Higgs production, in the general case where the MSSM includes complex phases, have been calculated. These results have been combined with all one-loop corrections of Standard Model type and with the propagator-type corrections from the Higgs sector of the MSSM up to the two-loop level. Within the Standard Model the electroweak corrections are found to be as important as the QCD corrections after the application of appropriate cuts. The corrections yield a shift in the cross section of order 5% for a Higgs of mass 100-200 GeV, confirming the result obtained previously in the literature. For the production of a light Higgs boson in the MSSM the Standard Model result is recovered in the decoupling limit, while the loop contributions from superpartners to the production of neutral MSSM Higgs bosons can give rise to corrections in excess of 10% away from the decoupling region. (orig.)

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

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.

Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set.

Science.gov (United States)

Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Binkley, M E; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calamba, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; 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; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chung, W H; Chung, Y S; Ciocci, M A; Clark, A; Clarke, C; Compostella, G; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; Dell'Orso, M; Demortier, L; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, S; Ershaidat, N; Eusebi, R; Farrington, S; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeans, D T; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kim, Y J; Kimura, N; Kirby, M; Klimenko, S; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; LeCompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Mastrandrea, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Prokoshin, F; Pranko, A; Ptohos, F; Punzi, G; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Sorin, V; Song, H; Squillacioti, P; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; 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; Zanetti, A; Zeng, Y; Zhou, C; Zucchelli, S

2012-09-14

We present a search for the standard model Higgs boson produced in association with a W boson in sqrt[s]=1.96  TeV pp collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45  fb(-1). In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H→bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125  GeV/c(2), we observe (expect) a limit of 4.9 (2.8) times the standard model value.

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

Higgs Signals in a Type I 2HDM or with a Sister Higgs

Energy Technology Data Exchange (ETDEWEB)

Alves, Daniele S.M. [Fermilab; Fox, Patrick J. [Fermilab; Weiner, Neal J. [New York U.

2012-07-01

In models where an additional SU(2)-doublet that does not have couplings to fermions participates in electroweak symmetry breaking, the properties of the Higgs boson are changed. At tree level, in the neighborhood of the SM-like range of parameter space, it is natural to have the coupling to vectors, cV, approximately constant, while the coupling to fermions, cf, is suppressed. This leads to enhanced VBF signals of gamma gamma while keeping other signals of Higgses approximately constant (such as WW* and ZZ*), and suppressing higgs to tau tau. Sizable tree-level effects are often accompanied by light charged Higgs states, which lead to important constraints from b to s gamma and top to b H+, but also often to similarly sizable contributions to the inclusive h to gamma gamma signal from radiative effects. In the simplest model, this is described by a Type I 2HDM, and in supersymmetry is naturally realized with 'sister Higgs' fields. In such a scenario, additional light charged states can contribute further with fewer constraints from heavy flavor decays. With supersymmetry, Grand Unification motivates the inclusion of colored partner fields. These G-quarks may provide additional evidence for such a model.

Higgs Pair Production as a Signal of Enhanced Yukawa Couplings

Energy Technology Data Exchange (ETDEWEB)

Bauer, Martin [Heidelberg U.; Carena, Marcela [Chicago U., KICP; Carmona, Adrián [U. Mainz, PRISMA

2017-12-31

We present a non-trivial correlation between the enhancement of the Higgs-fermion couplings and the Higgs pair production cross section in two Higgs doublet models with a flavour symmetry. This symmetry suppresses flavour-changing neutral couplings of the Higgs boson and allows for a partial explanation of the hierarchy in the Yukawa sector. After taking into account the constraints from electroweak precision measurements, Higgs coupling strength measurements, and unitarity and perturbativity bounds, we identify an interesting region of parameter space leading to enhanced Yukawa couplings as well as enhanced di-Higgs gluon fusion production at the LHC reach. This effect is visible in both the resonant and non-resonant contributions to the Higgs pair production cross section. We encourage dedicated searches based on differential distributions as a novel way to indirectly probe enhanced Higgs couplings to light fermions.

Exploring a heavy charged Higgs using jet substructure in a fully hadronic channel

Directory of Open Access Journals (Sweden)

Riley Patrick

2017-04-01

Full Text Available In the framework of the type-II Two Higgs Doublet Model (2HDM-II a charged Higgs search strategy is presented for the dominant production mode gb→tH± at the 14 TeV LHC. We consider the decay process which includes t→bW± and H±→AW±, and a fully hadronic final state consisting of bbb¯+jets+X. Dictated by the b→sγ constraints which render MH±>480 GeV we study two scenarios in which the charged Higgs mass is 750 GeV and the pseudoscalar Higgs mass is 200 GeV and 500 GeV. In this mass scheme highly boosted final state objects are expected and handled with jet substructure techniques which also acts to suppress the standard model background. A detailed detector analysis is performed, followed by a multivariate analysis involving many kinematic variables to optimize signal to background significance. Finally the LHC search sensitivities for the two scenarios are presented for various integrated luminosities.

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)

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)

7th Higgs Hunting 2016

CERN Document Server

2016-01-01

A subject of major importance in fundamental physics is the investigation of the origin of Electroweak Symmetry Breaking. The mechanism of mass generation through the spontaneous breaking of a gauge symmetry is called the Brout-Englert-Higgs mechanism and is associated with the appearance of a physical scalar boson. The discovery announced at CERN on 4th July 2012 by the ATLAS and CMS Collaborations of a boson at a mass close to 125 GeV/c2, compatible with this scalar boson of the Standard Model, the so-called Higgs boson, mainly in γγ, ZZ and WW decay modes, with compatible evidence also found at Fermilab in the bb mode, changed the landscape. This important discovery was acknowledged as decisive for the attribution of the 2013 Nobel Prize in Physics awarded jointly to François Englert and Peter Higgs . This 7th workshop of the "Higgs Hunting" series organized in Paris on August 31 - September 2, 2016 will discuss the developments of LHC run 2 analyses, detailed studies of the new boson and possible de...

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Madsen, Alexander; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the latest results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Vanadia, Marco; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the latest Run 1 results from the ATLAS Experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in wellmotivated BSM Higgs frameworks, including the two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Scutti, Federico; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are summarized. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Nagata, Kazuki; The ATLAS collaboration

2014-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs physics using the ATLAS experiment

CERN Document Server

Ernis, G; The ATLAS collaboration

2014-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Trilinear Higgs coupling determination via single-Higgs differential measurements at the LHC

Energy Technology Data Exchange (ETDEWEB)

Maltoni, Fabio; Shivaji, Ambresh; Zhao, Xiaoran [Universite Catholique de Louvain, Centre for Cosmology, Particle Physics and Phenomenology (CP3), Louvain-la-Neuve (Belgium); Pagani, Davide [Technische Universitaet Muenchen, Garching (Germany)

2017-12-15

We study one-loop effects induced by an anomalous Higgs trilinear coupling on total and differential rates for the H → 4l decay and some of the main single-Higgs production channels at the LHC, namely, VBF, VH, t anti tH and tHj. Our results are based on a public code that calculates these effects by simply reweighting samples of Standard-Model-like events for a given production channel. For VH and t anti tH production, where differential effects are particularly relevant, we include Standard Model electroweak corrections, which have similar sizes but different kinematic dependences. Finally, we study the sensitivity of future LHC runs to determine the trilinear coupling via inclusive and differential measurements, considering also the case where the Higgs couplings to vector bosons and the top quark is affected by new physics. We find that the constraints on the couplings and the relevance of differential distributions critically depend on the expected experimental and theoretical uncertainties. (orig.)

Trilinear Higgs coupling determination via single-Higgs differential measurements at the LHC

Science.gov (United States)

Maltoni, Fabio; Pagani, Davide; Shivaji, Ambresh; Zhao, Xiaoran

2017-12-01

We study one-loop effects induced by an anomalous Higgs trilinear coupling on total and differential rates for the H→ 4ℓ decay and some of the main single-Higgs production channels at the LHC, namely, VBF, VH, t{\\bar{t}}H and tHj. Our results are based on a public code that calculates these effects by simply reweighting samples of Standard-Model-like events for a given production channel. For VH and t{\\bar{t}}H production, where differential effects are particularly relevant, we include Standard Model electroweak corrections, which have similar sizes but different kinematic dependences. Finally, we study the sensitivity of future LHC runs to determine the trilinear coupling via inclusive and differential measurements, considering also the case where the Higgs couplings to vector bosons and the top quark is affected by new physics. We find that the constraints on the couplings and the relevance of differential distributions critically depend on the expected experimental and theoretical uncertainties.

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...

Higgs Production in a Warped Extra Dimension

Energy Technology Data Exchange (ETDEWEB)

Carena, Marcela [Chicago U., EFI; Casagrande, Sandro [Munich, Tech. U., Universe; Goertz, Florian [Zurich, ETH; Haisch, Ulrich [Oxford U., Theor. Phys.; Neubert, Matthias [Mainz U., Inst. Phys.

2012-04-01

Measurements of the Higgs-boson production cross section at the LHC are an important tool for studying electroweak symmetry breaking at the quantum level, since the main production mechanism gg-->h is loop-suppressed in the Standard Model (SM). Higgs production in extra-dimensional extensions of the SM is sensitive to the Kaluza-Klein (KK) excitations of the quarks, which can be exchanged as virtual particles in the loop. In the context of the minimal Randall-Sundrum (RS) model with bulk fields and a brane-localized Higgs sector, we derive closed analytical expressions for the gluon-gluon fusion process, finding that the effect of the infinite tower of virtual KK states can be described in terms of a simple function of the fundamental (5D) Yukawa matrices. Given a specific RS model, this will allow one to easily constrain the parameter space, once a Higgs signal has been established. We explain that discrepancies between existing calculations of Higgs production in RS models are related to the non-commutativity of two limits: taking the number of KK states to infinity and removing the regulator on the Higgs-boson profile, which is required in an intermediate step to make the relevant overlap integrals well defined. Even though the one-loop gg-->h amplitude is finite in RS scenarios with a brane-localized Higgs sector, it is important to introduce a consistent ultraviolet regulator in order to obtain the correct result.

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.

Electroweak symmetry breaking: Higgs/whatever

International Nuclear Information System (INIS)

Chanowitz, M.S.

1989-01-01

In the first of these two lectures the Higgs mechanism is reviewed in its most general form, which does not necessarily require the existence of Higgs bosons. The general consequences of the hypothesis that electroweak symmetry breaking is due to the Higgs mechanism are deduced just from gauge invariance and unitarity. In the second lecture the general properties are illustrated with three specific models: the Weinberg-Salam model, its minimal supersymmetric extension, and technicolor. The second lecture concludes with a discussion of the experiment signals for strong WW scattering, whose presence or absence will allow us to determine whether the symmetry breaking sector lies above or below 1 TeV. 57 refs

Lepton flavor violating Higgs couplings and single production of the Higgs boson via eγ collision

International Nuclear Information System (INIS)

Yue, Chong-Xing; Pang, Cong; Guo, Yu-Chen

2015-01-01

Taking into account the constraints on the lepton flavor violation (LFV) couplings of the Standard Model (SM) Higgs boson H with leptons from low energy experiments and the recent Compact Muon Solenoid experiment results, we investigate production of the SM Higgs boson associated with a lepton τ via eγ collision at the International Linear Collider (ILC) and Large Hadron Electron Collider experiments. The production cross sections are calculated and the LFV signals and the relevant SM backgrounds are examined. The LFV signals of the SM Higgs boson might be observed via eγ collision in future ILC experiments. (paper)

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.

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....

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)

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.

ATLAS Higgs Physics Prospects at the High Luminosity LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00218105; The ATLAS collaboration

2016-01-01

The High-Luminosity Large Hadron Collider will provide an unprecedented opportunity to study the properties of the Higgs boson and eventually probe for new physics beyond the Standard Model. The large anticipated data sample will allow for more precise investigations of topics already studied with earlier data samples, as well as for studies of processes that are accessible only with the much larger statistics. Rates and signal strengths will be measured for a variety of Higgs-boson production and decay modes, allowing extraction of the Higgs boson couplings. Particular final states will allow differential cross-sections to be measured for all production modes, and for studies of the Higgs width and CP properties, as well as the tensor structure of its coupling to bosons. An important part of the High-Luminosity LHC experimental program will be investigations of the Higgs self-coupling, which is accessible via studies of di-Higgs production. In this note the projections of the ATLAS physics reach in the Higgs...

Academic training: The Hunt for the Higgs Particle

CERN Multimedia

2007-01-01

2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 27, 28 February, 1st March, from 11:00 to 12:00 Main Auditorium, bldg. 500 The Hunt for the Higgs Particle F. ZWIRNER, University and INFN, Padova, Italy With the advent of the LHC, the hunt for the Higgs boson is entering its crucial phase. These three lectures will review: the Higgs mechanism; its implementation in the minimal Standard Model; possible alternatives with and without elementary scalar fields; the presently available information on electroweak gauge symmetry breaking and the Higgs particle; the properties of the Higgs boson(s) in the Standard Model and its supersymmetric extensions; the strategies for direct searches at colliders, with emphasis on the LHC, and comments on the possible scenarios that may emerge.

Minimal composite Higgs models at the LHC

Science.gov (United States)

Carena, Marcela; Da Rold, Leandro; Pontón, Eduardo

2014-06-01

We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5) → SO(4) symmetry breaking pattern, assuming the "partial compositeness" paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.

Seeking heavy Higgs bosons through cascade decays

Science.gov (United States)

Coleppa, Baradhwaj; Fuks, Benjamin; Poulose, P.; Sahoo, Shibananda

2018-04-01

We investigate the LHC discovery prospects for a heavy Higgs boson decaying into the standard model Higgs boson and additional weak bosons. We consider a generic model-independent new physics configuration where this decay proceeds via a cascade involving other intermediate scalar bosons and focus on an LHC final-state signature comprised either of four b -jets and two charged leptons or of four charged leptons and two b -jets. We design two analyses of the corresponding signals, and demonstrate that a 5 σ discovery at the 14 TeV LHC is possible for various combinations of the parent and daughter Higgs-boson masses. We moreover find that the standard model backgrounds can be sufficiently rejected to guarantee the reconstruction of the parent Higgs boson mass. We apply our analyses to the Type-II two-Higgs-doublet model and identify the regions of the parameter space to which the LHC is sensitive.

Minimal composite Higgs models at the LHC

International Nuclear Information System (INIS)

Carena, Marcela; Rold, Leandro Da; Pontón, Eduardo

2014-01-01

We consider composite Higgs models where the Higgs is a pseudo-Nambu Goldstone boson arising from the spontaneous breaking of an approximate global symmetry by some underlying strong dynamics. We focus on the SO(5)→SO(4) symmetry breaking pattern, assuming the “partial compositeness" paradigm. We study the consequences on Higgs physics of the fermionic representations produced by the strong dynamics, that mix with the Standard Model (SM) degrees of freedom. We consider models based on the lowest-dimensional representations of SO(5) that allow for the custodial protection of the Zb-barb coupling, i.e. the 5, 10 and 14. We find a generic suppression of the gluon fusion process, while the Higgs branching fractions can be enhanced or suppressed compared to the SM. Interestingly, a precise measurement of the Higgs boson couplings can distinguish between different realizations in the fermionic sector, thus providing crucial information about the nature of the UV dynamics.

Higgs versus matter in the heterotic landscape

International Nuclear Information System (INIS)

Buchmueller, W.; Schmidt, J.

2009-01-01

In supersymmetric extensions of the standard model there is no basic difference between Higgs and matter fields, which leads to the well-known problem of potentially large baryon and lepton number violating interactions. Although these unwanted couplings can be forbidden by continuous or discrete global symmetries, a theoretical guiding principle for their choice is missing. We examine this problem for a class of vacua of the heterotic string compactified on an orbifold. As expected, in general there is no difference between Higgs and matter. However, certain vacua happen to possess unbroken matter parity and discrete R-symmetries which single out Higgs fields in the low energy effective field theory. We present a method how to identify maximal vacua in which the perturbative contribution to the μ-term and the expectation value of the superpotential vanish. Two vacua are studied in detail, one with two pairs of Higgs doublets and one with partial gauge-Higgs unification

W+W- interactions and the search for the Higgs boson

International Nuclear Information System (INIS)

Levi, M.E.

1989-07-01

Since the original paper by Peter Higgs in 1964, which was only a page and a half long, the number of publications on the topic of the Higgs particle has grown year by year and threatens to overwhelm us. If only for this reason it has become imperative that we find the Higgs. In this lecture series we will begin with a general review of the standard model Higgs and a summary of existing experimental limits on Higgs masses. We will then discuss Higgs searches at e + e - machines which are just coming on line, e.g. SLC and LEP, and proceed to work our way up to TLC, CLIC, and the SSC, where we will introduce the topic of W + W - interactions. The range of Higgs masses we cover will span six orders of magnitude from MeV to TeV. Non-minimal Higgs searches will not be dealt with in this lecture series; instead see the excellent theoretical reviews of both minimal and non-minimal model Higgs. 55 refs., 51 figs., 20 tabs

High-energy vector boson scattering after the Higgs discovery

International Nuclear Information System (INIS)

Kilian, Wolfgang; Sekulla, Marco; Ohl, Thorsten; Reuter, Juergen

2014-08-01

Weak vector-boson W,Z scattering at high energy probes the Higgs sector and is most sensitive to any new physics associated with electroweak symmetry breaking. We show that in the presence of the 125 GeV Higgs boson, a conventional effective-theory analysis fails for this class of processes. We propose to extrapolate the effective-theory ansatz by an extension of the parameter-free K-matrix unitarization prescription, which we denote as direct T-matrix unitarization. We generalize this prescription to arbitrary non-perturbative models and describe the implementation, as an asymptotically consistent reference model matched to the low-energy effective theory. We present exemplary numerical results for full six-fermion processes at the LHC.

B¯→Xsγ with a warped bulk Higgs

Directory of Open Access Journals (Sweden)

P. Moch

2016-01-01

Full Text Available We study the decay B¯→Xsγ in Randall–Sundrum models with an IR-localised bulk Higgs. The two models under consideration are a minimal model and a model with a custodial protection mechanism. We include the effects of tree- and one-loop diagrams involving 5D gluon and Higgs exchanges as well as QCD corrections arising from the evolution from the Kaluza–Klein scale to the typical scale of the decay. We find the RS corrections to the branching fraction can be sizeable for large Yukawas and moderate KK scales T; for small Yukawas the RS contribution is small enough to be invisible in current experimental data.

Higgs physics at the CLIC electron-positron linear collider.

Science.gov (United States)

Abramowicz, H; Abusleme, A; Afanaciev, K; Alipour Tehrani, N; Balázs, C; Benhammou, Y; Benoit, M; Bilki, B; Blaising, J-J; Boland, M J; Boronat, M; Borysov, O; Božović-Jelisavčić, I; Buckland, M; Bugiel, S; Burrows, P N; Charles, T K; Daniluk, W; Dannheim, D; Dasgupta, R; Demarteau, M; Díaz Gutierrez, M A; Eigen, G; Elsener, K; Felzmann, U; Firlej, M; Firu, E; Fiutowski, T; Fuster, J; Gabriel, M; Gaede, F; García, I; Ghenescu, V; Goldstein, J; Green, S; Grefe, C; Hauschild, M; Hawkes, C; Hynds, D; Idzik, M; Kačarević, G; Kalinowski, J; Kananov, S; Klempt, W; Kopec, M; Krawczyk, M; Krupa, B; Kucharczyk, M; Kulis, S; Laštovička, T; Lesiak, T; Levy, A; Levy, I; Linssen, L; Lukić, S; Maier, A A; Makarenko, V; Marshall, J S; Martin, V J; Mei, K; Milutinović-Dumbelović, G; Moroń, J; Moszczyński, A; Moya, D; Münker, R M; Münnich, A; Neagu, A T; Nikiforou, N; Nikolopoulos, K; Nürnberg, A; Pandurović, M; Pawlik, B; Perez Codina, E; Peric, I; Petric, M; Pitters, F; Poss, S G; Preda, T; Protopopescu, D; Rassool, R; Redford, S; Repond, J; Robson, A; Roloff, P; Ros, E; Rosenblat, O; Ruiz-Jimeno, A; Sailer, A; Schlatter, D; Schulte, D; Shumeiko, N; Sicking, E; Simon, F; Simoniello, R; Sopicki, P; Stapnes, S; Ström, R; Strube, J; Świentek, K P; Szalay, M; Tesař, M; Thomson, M A; Trenado, J; Uggerhøj, U I; van der Kolk, N; van der Kraaij, E; Vicente Barreto Pinto, M; Vila, I; Vogel Gonzalez, M; Vos, M; Vossebeld, J; Watson, M; Watson, N; Weber, M A; Weerts, H; Wells, J D; Weuste, L; Winter, A; Wojtoń, T; Xia, L; Xu, B; Żarnecki, A F; Zawiejski, L; Zgura, I-S

2017-01-01

The Compact Linear Collider (CLIC) is an option for a future [Formula: see text] collider operating at centre-of-mass energies up to [Formula: see text], providing sensitivity to a wide range of new physics phenomena and precision physics measurements at the energy frontier. This paper is the first comprehensive presentation of the Higgs physics reach of CLIC operating at three energy stages: [Formula: see text], 1.4 and [Formula: see text]. The initial stage of operation allows the study of Higgs boson production in Higgsstrahlung ([Formula: see text]) and [Formula: see text]-fusion ([Formula: see text]), resulting in precise measurements of the production cross sections, the Higgs total decay width [Formula: see text], and model-independent determinations of the Higgs couplings. Operation at [Formula: see text] provides high-statistics samples of Higgs bosons produced through [Formula: see text]-fusion, enabling tight constraints on the Higgs boson couplings. Studies of the rarer processes [Formula: see text] and [Formula: see text] allow measurements of the top Yukawa coupling and the Higgs boson self-coupling. This paper presents detailed studies of the precision achievable with Higgs measurements at CLIC and describes the interpretation of these measurements in a global fit.

New fat Higgs: Increasing the MSSM Higgs mass with natural gauge unification

International Nuclear Information System (INIS)

Chang, Spencer; Kilic, Can; Mahbubani, Rakhi

2005-01-01

In this paper we increase the minimal supersymmetric standard model tree level Higgs mass bound to a value that is naturally larger than the LEP-II search constraint by adding to the superpotential a λSH u H d term, as in the next to minimal supersymmetric standard model, and UV completing with new strong dynamics before λ becomes nonperturbative. Unlike other models of this type, the Higgs fields remain elementary, alleviating the supersymmetric fine-tuning problem while maintaining unification in a natural way

Higgs bosons in extra dimensions

Science.gov (United States)

Quiros, Mariano

2015-05-01

In this paper, motivated by the recent discovery of a Higgs-like boson at the Large Hadron Collider (LHC) with a mass mH≃125 GeV, we review different models where the hierarchy problem is solved by means of a warped extra dimension. In the Randall-Sundrum (RS) model electroweak observables provide very strong bounds on the mass of KK modes which motivates extensions to overcome this problem. Two extensions are briefly discussed. One particular extension is based on the deformation of the metric such that it strongly departs from the AdS5 structure in the IR region while it goes asymptotically to AdS5 in the UV brane. This model has the IR brane close to a naked metric singularity (which is outside the physical interval) characteristic of soft-walls constructions. The proximity of the singularity provides a strong wave function renormalization for the Higgs field which suppresses the T and S parameters. The second class of considered extensions are based on the introduction of an extra gauge group in the bulk such that the custodial SU(2)R symmetry is gauged and protects the T parameter. By further enlarging the bulk gauge symmetry one can find models where the Higgs is identified with the fifth component of gauge fields and for which the Higgs potential along with the Higgs mass can be dynamically determined by the Coleman-Weinberg mechanism.

On stability of the electroweak vacuum and the Higgs portal

International Nuclear Information System (INIS)

Lebedev, Oleg

2012-03-01

In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that an arbitrarily small mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass, which survives in the zero--mixing/heavy--singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self--coupling can be measured. As a result, Higgs inflation and its variants can still be viable.

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.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Vanadia, Marco; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV/$\\rm{c^2}$ has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this report, the latest Run 1 results from the ATLAS Experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well motivated BSM Higgs frameworks, including the two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

On stability of the electroweak vacuum and the Higgs portal

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Oleg

2012-03-15

In the Standard Model (SM), the Higgs mass around 125 GeV implies that the electroweak vacuum is metastable since the quartic Higgs coupling turns negative at high energies. I point out that an arbitrarily small mixing of the Higgs with a heavy singlet can make the electroweak vacuum completely stable. This is due to a tree level correction to the Higgs mass, which survives in the zero--mixing/heavy--singlet limit. Such a situation is experimentally indistinguishable from the SM, unless the Higgs self--coupling can be measured. As a result, Higgs inflation and its variants can still be viable.

Search for B-decay to Higgs bosons for Higgs boson masses between 50 and 210 MeV/c2

International Nuclear Information System (INIS)

Snyder, A.; Murray, W.N.; Blockus, D.; Brabson, B.; Brom, J.M.; Ogren, H.; Rust, D.R.; Abrams, G.; Amidei, D.; Baden, A.R.; Boyer, J.; Butler, F.; Drell, P.S.; Gidal, G.; Gold, M.S.; Goldhaber, G.; Haggerty, J.; Harr, R.; Herrup, D.; Jaffre, M.; Juricic, I.; Kadyk, J.A.; Levi, M.E.; Rowson, P.C.; Schellman, H.; Schmidke, W.B.; Sheldon, P.D.; Trilling, G.H.; Wood, D.R.; Akerlof, C.; Bonvicini, G.; Chapman, J.; Frey, R.; Koska, W.; Meyer, D.I.; Nitz, D.; Petradza, M.; Thun, R.; Tschirhart, R.; Veltman, H.; Alexander, J.P.; Barklow, T.; Bartelt, J.; Boyarski, A.; Bulos, F.; Burke, D.L.; Cords, D.; Coupal, D.P.; Destaebler, H.C.; Dorfan, J.M.; Feldman, G.J.; Field, R.C.; Fordham, C.; Fujino, D.; Gan, K.K.; Gladney, L.; Glanzman, T.; Grosse-Wiesmann, P.; Hanson, G.; Hayes, K.; Himel, T.; Hollebeek, R.J.; Hutchinson, D.; Innes, W.R.; Jaros, J.A.; Karlen, D.; Klein, S.R.; Kozanecki, W.; Lankford, A.J.; Larsen, R.R.; Leclaire, B.W.; Lockyer, N.S.; Lueth, V.; Moffeit, K.C.; Mueller, L.; Nash, J.; Ong, R.A.; O'Shaughnessy, K.F.; Perl, M.L.; Petersen, A.; Richter, B.; Riles, K.; Van Kooten, R.; Voruganti, P.; Yelton, J.M.; Alvarez, M.; Calvino, F.; Fernandez, E.; Ford, W.T.; Rankin, P.; Smith, J.G.; Wagner, S.R.; Weber, P.; White, S.L.; Barish, B.C.; Hawkes, C.M.; Milliken, B.D.; Nelson, M.E.; Peck, C.; Porter, F.C.; Soderstrom, E.; Stroynowski, R.; Wicklund, E.; Weir, A.J.; Wu, D.Y.; Barnett, B.A.; Hylen, J.; Matthews, J.A.J.; Stoker, D.P.; Breakstone, A.; Cence, R.J.; Parker, S.I.; Schaad, T.

1989-01-01

We use data from the Mark II experiment at PEP to search for the process B→h 0 X for m h0 between 50 and 210 MeV/c 2 . No evidence for the Higgs boson is seen in this mass range. The limit obtained rules out the standard Higgs boson for masses between 70 and 210 MeV/c 2 and significantly constrains extensions of the Higgs sector. (orig.)

Search for Higgs portal DM at the ILC

Energy Technology Data Exchange (ETDEWEB)

Ko, P. [School of Physics, KIAS,Seoul 02455 (Korea, Republic of); Quantum Universe Center, KIAS,Seoul 02455 (Korea, Republic of); Yokoya, Hiroshi [Quantum Universe Center, KIAS,Seoul 02455 (Korea, Republic of)

2016-08-18

Higgs portal dark matter (DM) models are simple interesting and viable DM models. There are three types of the models depending on the DM spin: scalar, fermion and vector DM models. In this paper, we consider renormalizable, unitary and gauge invariant Higgs portal DM models, and study how large parameter regions can be surveyed at the International Linear Collider (ILC) experiment at √s=500 GeV. For the Higgs portal singlet fermion and vector DM cases, the force mediator involves two scalar propagators, the SM-like Higgs boson and the dark Higgs boson. We show that their interference generates interesting and important patterns in the mono-Z plus missing E{sub T} signatures at the ILC, and the results are completely different from those obtained from the Higgs portal DM models within the effective field theories. In addition, we show that it would be possible to distinguish the spin of DM in the Higgs portal scenarios, if the shape of the recoil-mass distribution is observed. We emphasize that the interplay between these collider observations and those in the direct detection experiments has to be performed in the model with renomalizability and unitarity to combine the model analyses in different scales.

Partially natural Two Higgs Doublet Models

Energy Technology Data Exchange (ETDEWEB)

Draper, Patrick [Department of Physics, University of California,Broida Hall, Santa Barbara, CA 93106 (United States); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California,1156 High Street, Santa Cruz, CA 95064 (United States); Kavli Institute for Theoretical Physics, University of California,Kohn Hall, Santa Barbara, CA 93106 (United States); Ruderman, Joshua T. [Center for Cosmology and Particle Physics, Department of Physics, New York University,4 Washington Pl. New York, NY 10003 (United States)

2016-06-21

It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions at the electroweak scale, and the models possess a rich electroweak vacuum structure. The mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.

Off-the-Wall Higgs in the universal Randall-Sundrum model

International Nuclear Information System (INIS)

Davoudiasl, Hooman; Lillie, Ben; Rizzo, Thomas G.

2006-01-01

We outline a consistent Randall-Sundrum (RS) framework in which a fundamental 5-dimensional Higgs doublet induces electroweak symmetry breaking (EWSB). In this framework of a warped Universal Extra Dimension, the lightest Kaluza-Klein (KK) mode of the bulk Higgs is tachyonic leading to a vacuum expectation value (vev) at the TeV scale. The consistency of this picture imposes a set of constraints on the parameters in the Higgs sector. A novel feature of our scenario is the emergence of an adjustable bulk profile for the Higgs vev. We also find a tower of non-tachyonic Higgs KK modes at the weak scale. We consider an interesting implementation of this 'Off-the-Wall Higgs' mechanism where the 5-dimensional curvature-scalar coupling alone generates the tachyonic mode responsible for EWSB. In this case, additional relations among the parameters of the Higgs and gravitational sectors are established. We discuss the experimental signatures of the bulk Higgs in general, and those of the 'Gravity-Induced' EWSB in particular

Improved formalism for precision Higgs coupling fits

Science.gov (United States)

Barklow, Tim; Fujii, Keisuke; Jung, Sunghoon; Karl, Robert; List, Jenny; Ogawa, Tomohisa; Peskin, Michael E.; Tian, Junping

2018-03-01

Future e+e- colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e+e- data, based on the effective field theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e+e- colliders.

Improved formalism for precision Higgs coupling fits

International Nuclear Information System (INIS)

Barklow, Tim; Peskin, Michael E.; Jung, Sunghoon; Tian, Junping

2017-08-01

Future e + e - colliders give the promise of model-independent determinations of the couplings of the Higgs boson. In this paper, we present an improved formalism for extracting Higgs boson couplings from e + e - data, based on the Effective Field Theory description of corrections to the Standard Model. We apply this formalism to give projections of Higgs coupling accuracies for stages of the International Linear Collider and for other proposed e + e - colliders.

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.

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

String tension in the three-dimensional Abelian Higgs model

International Nuclear Information System (INIS)

Farakos, K.; Koutsoumbas, G.; Sarantakos, S.

1988-01-01

We measure the expectation values of the Wilson loops for the radially active Abelian Higgs model in three dimensions with Higgs charge q = 1 and q = 2. We observe a drastic fall-off of the area term as we pass to the Higgs phase, as well as a peak of the perimetric term at the phase transition. Implications of our results for other Higgs models are also discussed. (orig.)

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.)

Searches for neutral Higgs bosons in extended models

NARCIS (Netherlands)

Abdallah, J.; Blom, M.R.; Drees, J.; Palacios, J.; van der Pol, M.; Siebel, M.; van Dam, P.A.; Zupan, M.

2004-01-01

Searches for neutral Higgs bosons produced at LEP in association with Z bosons, in pairs and in the Yukawa process are presented in this paper. Higgs boson decays into b quarks, τ leptons, or other Higgs bosons are considered, giving rise to four-b, four-b+jets, six-b and four-τ final states, as

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.

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.