Search

The left-right twin Higgs (LRTH) model is a concrete realization of the twin Higgs mechanism, which predicts the existence of a new heavy top quark (T) and charged Higgs boson (ϕ±). Detecting of these new particles in the LRTH model depends on free parameters (f, f̂, M) which are constrained by the electroweak precision measurments. We study the associated production of a charged Higgs boson (ϕ+) and a heavy top quark (T) via e− e+→ϕ+T̅b in the framework the LRTH model at √s=3000GeV and yearly integrated luminosity of L=500 fb−1. We find that the production cross section of the process e−e+→ϕ+T̅b can reach to the level of several tens fb and a statical significance of 5σ can be achieved in the suitable parameter space of the LRTH model at √s=3000GeV. [ABSTRACT FROM AUTHOR]

Looking back to the discovery of weak neutral currents [ABSTRACT FROM AUTHOR]

Because muons connect directly to a standard-model Higgs particle in s-channel production, a muon colliderwould be an ideal device for precision measurement of the mass and width of a Higgs-like particle, and for further exploration of its production and decay properties. The LHC has seen evidence for a 125 GeV Higgs particle, and a muon collider at that energy could be constructed. Parameters of a high-precision muon collider are presented and the necessary components and performance are described. Extension to a higher-energy higher-luminosity device is also discussed. [ABSTRACT FROM AUTHOR]

I present a new solution to the doublet-triplet splitting problem which works also in a SUSY SU(5) GUT and is testable at TeV-scale collider experiments. In this model, the SU(5) symmetry is broken through the Hosotani mechanism. Thanks to the phase nature of the Hosotani-breaking, the so-called "missing VEV" can be realized even in an SU(5) model to solve the problem. A general and distinctive prediction of this solution is the existence of light adjoint chiral supermultiplets with masses of the SUSY breaking scale which would be observed at the LHC. [ABSTRACT FROM AUTHOR]

An overview of the searches for Higgs bosons at the Tevatron and the LHC is presented. The main Higgs production and decay modes are introduced, and the analysis techniques are described. The most recent results from direct Tevatron and LHC Higgs searches are presented. [ABSTRACT FROM AUTHOR]

I discuss Double Pomeron Exchange processes from their first observation at the CERN Intersecting Storage Rings, focusing on glueball searches, through the observations of exclusive χc0, γγ and di-jets at the Tevatron, to prospects at the LHC for exclusive Higgs boson production. [ABSTRACT FROM AUTHOR]

The right-handed sneutrino is a viable WIMP dark matter candidate within the context of the Next-to-MSSM through the inclusion of a new singlet superfield with direct coupling to the singlet Higgs. Sneutrinos within a mass-range of 5–200 GeV can reproduce the correct dark matter relic abundance while not being excluded by current direct searches, and for natural values of the input parameters. Some interesting features regarding collider phenomenology are also pointed out. [ABSTRACT FROM AUTHOR]

We present the latest results of searches for the production of Higgs bosons at the Tevatron collider in the D0 and CDF experiments. Cross section times branching ratios have been measured in many different topologies and have been interpreted in both the standard model and other models. No evidence for the production of Higgs bosons has been observed, but limits have been set. The D0 and CDF searches in the standard model have been combined and for the first time we exclude part of the possible mass range, 160 GeV to 170 GeV at the 95% confidence level. [ABSTRACT FROM AUTHOR]

An alternative process is presented for diffractive Higgs boson production in peripheral pp collisions, where the particles interact through the Double Pomeron Exchange. The event rate is computed as a central-rapidity distribution for Tevatron and LHC energies leading to a result around 0.6 pb, higher than the predictions from previous approaches. Therefore, this result arises as an enhanced signal for the detection of the Higgs boson in hadron colliders. The predictions for the Higgs boson photoproduction are compared to the ones obtained from a similar approach proposed by the Durham group, enabling an analysis of the future developments of its application to pp and AA collisions. [ABSTRACT FROM AUTHOR]

Results on diffraction from the Fermilab Tevatron collider obtained by the CDF II Collaboration using data from pp collisions at [formula] are reviewed and compared with theoretical expectations. Implications for predictions of exclusive Higgs boson production rates at the Large Hadron Collider are discussed. [ABSTRACT FROM AUTHOR]

The SU(2)L × U(1)Y gauge theory of the electroweak interactions has enjoyed tremendous success over the past four decades, accurately predicting, or at least accommodating, all high-energy collider data. The gauge group must be broken somehow to U(1)EM, because the unbroken theory predicts massless gauge bosons and massless fermions. The Standard Model incorporates a minimal Higgs sector with a single complex doublet field, to break the symmetry spontaneously, but it is not the only possibility. SUSY Higgses, general two-Higgs-doublet models, and other ideas may prove to model nature better than the minimal model. Many of these models, and even the SM, prefer a light Higgs boson, with a mass between the LEP limit of 114.4 GeV and 200 GeV. The Constrained MSSM favors masses under 120 GeV. A survey of the experimental work so far at LEP and the Tevatron, with estimations of the sensitivity of the upcoming LHC experiments is provided. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The status of QCD corrections to Higgs boson production in hadronic colliders is summarized. Results are presented for the transverse momentum distribution at the LHC including the resummation of the dominating logarithmic contributions to all orders in the coupling constant. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The flavor democracy hypothesis (or, in other words, democratic mass matrix approach) was introduced in seventies taking in mind three Standard Model (SM) families. Later, this idea was disfavored by the large value of the t-quark mass. In nineties the hypothesis was revisited assuming that extra SM families exist. According to flavor democracy the fourth SM family should exist and there are serious arguments disfavoring the fifth SM family. The fourth SM family quarks lead to essential enhancement of the Higgs boson production cross-section at hadron colliders and the Tevatron can discover the Higgs boson before the LHC, if it mass is between 140 and 200 GeV. Then, one can handle “massless” Dirac neutrinos without see-saw mechanism. Concerning BSM physics, flavor democracy leads to several consequences: tanβ ≈ mt/mb ≈ 40 if there are three MSSM families; super-partner of the right-handed neutrino can be the LSP; relatively light E(6)-inspired isosinglet quark etc. Finally, flavor democracy may give opportunity to handle “massless” composite objects within preonic models. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

With relatively low backgrounds and a well-determined initial state, the proposed International Linear Collider (ILC) would provide a precision complement to the LHC experiments at the energy frontier. Completely and precisely exploring the discoveries of the LHC with such a machine will be critical in understanding the nature of those discoveries and what, if any, new physics they represent. The unique ability to form a complete picture of the Higgs sector is a prime example of the probative power of the ILC and represents a new era in precision physics. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

We report on direct searches for Higgs bosons carried out by the CDF and DØ Collaborations in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. Limits on the production cross section times branching fraction will be presented and a brief discussion of searches for supersymmetric Higgs bosons will be given. We will focus mainly on recent results only (those released in 2006), based on data sets of 260 – 950 fb-1 of data collected between 2004 – 2006. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this paper I present the most recent results of the ongoing searches, mainly from Tevatron Collider experiments, for new physics beyond the Standard Model. While no signal has been seen so far, many analyses are reaching the point in which either a discovery will take place or strong limit on currently popular theories will be set. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

I summarize some recent work on supersymmetric neutralinos as candidates for cold Dark Matter in the Universe. This includes a new scan of mSUGRA parameter space, with special emphasis on neutralinos annihilating predominantly through exchange of the light CP-even Higgs boson, and on bounds on sparticle masses. Next, prospects of testing models with TeV higgsino-like Dark Matter at colliders are discussed. Finally, I briefly comment on extensions of the mSUGRA model, and on scenarios with non-standard cosmology. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

I discuss central exclusive production, also known as Double Pomeron Exchange, DIPE, from the ISR through the Tevatron to the LHC. There I emphasize the interest of exclusive Higgs and W+W-/ZZ production. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The search for the Higgs boson, introduced to give a dynamical mass to Standard Model particles, is one of the crucial tasks of LHC experiments. This proceeding reviews and evaluates the potential discovery of the main channels for the Standard Model Higgs boson at this accelerator. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

I present a brief theoretical update on top quark pair production at the Tevatron and give values of the NNLO-NNNLL cross section for both mt = 175 and 178 GeV. I then present a calculation of the cross section for charged Higgs production in association with a top quark at the LHC, including NNLO soft-gluon corrections. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The Tevatron Electroweak Working group was created in September, 2003 at Fermilab to consolidate electroweak physics results for precision Standard Model tests. It is the first combined analysis group at Fermilab to publish in a refereed journal. The group currently has 49 subscribers. Three subgroups are dedicated to studies of W and Z boson properties, top quark properties, and Higgs physics respectively. The group has produced combined results from the CDF and DØ experiments on the Run 1 W boson mass and width, the Run 1 top quark mass, and the Run 2 measurement of the ratio of W and Z boson cross sections. New results are anticipated as Run 2 analyses mature. The group also organizes joint workshops for theorists and experimentalists. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

CMS and Atlas sensitivity to Standard Model Higgs boson discovery is discussed with the emphasis on aspects that could be verified by Tevatron experiments. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

In this talk, I will discuss possible new physics effects that modify the interaction of Higgs boson(s) with top and bottom quarks, and discuss how to detect such effects in current and future high energy colliders. [ABSTRACT FROM AUTHOR]

We study the production of the Higgs bosons predicted in the Minimal Supersymmetric extension of the Standard Model (h[sup 0],H[sup 0],A[sup 0],H[sup ±]), with the reactions e[sup +] e[sup -] → b&bmacr;h[sup 0] (H[sup 0], A[sup 0]), and e[sup +]e[sup -] → τ[sup -]&vmacr;[sub τ]H[sup +], τ[sup +]v[sub &tau]H[sup -], using the helicity formalism. We evaluate cross section of h[sup 0],H[sup 0],A[sup 0] and H[sup ±] in the limit when tan β is large. The numerical computation is done considering two stages of a possible Next Linear e[sup +]e[sup -] Collider: the first with √s = 500 GeV and design luminosity 50 fb[sup -1], and the second with √s = 1 TeV and luminosity 100-200 fb[sup -1]. [ABSTRACT FROM AUTHOR]

Subjects of discussion 1. Different scenarios 2. Higgs window to a New Physics 3. Anomalies in the interactions of gauge and Higgs bosons 4. Some problems in QCD and hadron physics. 5. By-product: Production of axions, etc. from region of conversion e→γ. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We discuss associated production of a Higgs boson with a pair of t&tmacr; quarks at a future high energy e[sup +]e[sup -] collider. The process e[sup +]e[sup -] → t&tmacr;h is particularly sensitive to the presence of new physics and we consider the MSSM and models with extra dimensions at the TeV scale as examples. [ABSTRACT FROM AUTHOR]

Future γγ colliders allow the production of the heavy neutral MSSM Higgs bosons H and A as single resonances. The prospects of finding these particles in the b&bmacr; and the neutralino-pair final states have been analysed. The H, A bosons can be discovered for medium values of tan β with masses up to 70–80% of the initial e[sup ±]e[sup -] c.m. energy. This production mode thus covers parts of the supersymmetric parameter space that are not accessible at other colliders. [ABSTRACT FROM AUTHOR]

After operations at the LHC and e[sup +]e[sup -] Linear Colliders it may be found that a Standard-Model-like scenario is realized. In this scenario no new particle will be discovered, except a single Higgs boson having partial widths or coupling constants with fundamental particles, whose squares are close, within anticipated experimental uncertainty, to those of the SM. Experiments at a Photon Collider can resolve whether the SM or e.g. the Two-Higgs-Doublet Model is realized in Nature. For the SM-like realizations of the 2HDM (II) we study the loop couplings of the Higgs boson with γγ and Zγ, and also with gluons. The deviation of the two-photon width from its SM value is generally higher than the expected inaccuracy in the measurement of Γ[sub γγ] at a Photon Collider. The deviation is sensitive to the parameters of the Higgs self interaction. [ABSTRACT FROM AUTHOR]

A muon collider operating in the TeV energy range can be an ideal s-channel Higgs boson factory. This is especially true for a very heavy Higgs boson. The non-perturbative dynamical aspects of such a Higgs boson were recently investigated with large N expansion methods at next to leading order, and reveal the existence of a mass saturation effect. Even at strong coupling, the Higgs resonance remains always below 1 TeV. However, if the coupling is strong enough, the resonance becomes impossible to be detected. [ABSTRACT FROM AUTHOR]

We study the observability of the τ[sup -]τ[sup +] decay mode of a Higgs boson produced in the s-channel at a muon collider. We find that the spin correlations of the τ[sup -]τ[sup +] in τ → πv[sub τ], ρv[sub τ] decays are discriminative between the Higgs boson signal and the Standard Model background. Observation of the predicted distinctive distribution can confirm the spin-0 nature of the Higgs resonance. The relative coupling strength of the Higgs boson to b and τ can also be experimentally determined. [ABSTRACT FROM AUTHOR]

I describe and motivate suggestions for modifications of the Higgs boson decay that would cause it to be missed in the standard searches conducted at LEP2. I follow with recent progress in the search for such exotic Higgs decays in the various colliders. [ABSTRACT FROM AUTHOR]

We present searches for Higgs bosons ([lowercase_phi_synonym]) in the framework of MSSM models using up to 7.3 fb-1 of data collected with the DO\ detector in proton-antiproton collisions at a center of mass energy of 1.96 TeV at the Fermilab Tevatron collider. In addition, we discuss searches for doubly-charged Higgs bosons and fermiophobic Higgs bosons. [ABSTRACT FROM AUTHOR]

In both Supersymmetry and in generic Two Higgs Doublet models (2HDM), the charged Higgs boson H± exhibits a unique phenomenological signature. We report on a search for charged Higgs bosons, performed using 0.9 fb-1 of data collected with the D0 detector at the Fermilab Tevatron pp collider with a center-of-mass energy of s = 1.96 TeV. No evidence for a charged Higgs boson is found and we set limits on its production cross section or the branching fraction. [ABSTRACT FROM AUTHOR]

We present two searches for the Higgs boson in √s = 1.96 TeV p... collisions using data taken with the DØ detector during Run II of the Fermilab Tevatron collider. The first study is a search for neutral Higgs bosons produced in association with bottom quarks. The cross sections for these processes are enhanced in many extensions of the standard model (SM), such as in its minimal supersymmetric extension at large tanβ. The results of our analysis agree with expectations from the SM, and we use our measurements to set upper limits on the production of neutral Higgs bosons in the mass range of 90 to 150 GeV. The second study is a search for the standard model Higgs boson produced in association with the Z boson. We study the p... → ZH → v...b... channel, which is one of the most sensitive ways to search for light Higgs bosons at the Tevatron. We select multijet events with large imbalance in transverse momentum and two b-tagged jets. Then we search for a peak in invariant mass distribution of two b-tagged jets. After subtracting the backgrounds, we set the 95% C.L. upper limits on the σ(p... → ZH → v...) × BR(H → b...) for Higgs masses between 105 and 135 GeV. [ABSTRACT FROM AUTHOR]