Decays of Higgs Bosons Into a Gauge Boson and a Fermion-Antifermion Pair

Russian Physics Journal - Decay channels of the Higgs boson H into a gauge boson and a longitudinally polarized fermion-antifermion pair $$ Hto Zoverline{ff} $$ and $$ Hto...     

Decays of heavy Higgs Bosons into vector Bosons

The decays Higgs → Higgs + V (V = W, Z) are studied in the Weinberg-Salam model with two Higgs doublets and are shown to exceed the usual fermion decay mode with known fermions and the mode V$\text{V}$ in a large region of Higgs masses and mixing angles. Higgs-Higgs final states and the role of the heavy Higgs decays are briefly discussed.     

Decays of Higgs Bosons Into a Fermion-Antifermion Pair

Russian Physics Journal - Within the framework of the Minimal Supersymmetric Standard Model, decay channels of Higgs bosons (h, A), H± into arbitrarily polarized fermion-antifermion pairs $$...     

Search for Down-Type Fourth Generation Quarks with the ATLAS Detector in Events with One Lepton and Hadronically Decaying W Bosons

This Letter presents a search for pair production of heavy down-type quarks decaying via b^{'}→Wt in the lepton+jets channel, as b^{'}b[over ˉ]^{'}→W^{-}tW^{+}t[over ˉ]→bb[over ˉ]W^{+}W^{-}W^{+}W^{-}→l^{±}νbb[over ˉ]qq[over ˉ]qq[over ˉ]qq[over ˉ]. In addition to requiring exactly one lepton, large missing transverse momentum, and at least six jets, the invariant mass of nearby jet pairs is used to identify high transverse momentum W bosons. In data corresponding to an integrated luminosity of 1.04 fb^{-1} from pp collisions at sqrt[s]=7 TeV recorded with the ATLAS detector, a heavy down-type quark with mass less than 480?GeV can be excluded at the 95% confidence level.     

Effects of R-parity Violation on the Charged Higgs Boson Decays

We calculate one-loop R-parity-violating coupling corrections to the processes H^-→τν_τ and H^-→bt. We find that the corrections to the H^-→τν_τ decay mode are generally about 0.1%, and can be negligible. But the corrections to the H^-→bt decay mode can reach a few percent for the favored parameters.     

Search for New Heavy Higgs Bosons in the ATLAS and CMS Experiments at the LHC (Brief Review)

JETP Letters - The discovery of the Higgs boson by the ATLAS and CMS collaborations in 2012 was an important milestone in the modern elementary particle physics, which finally confirm the Standard...     

Three-Particle Decays of the Higgs Bosons in the Minimal Supersymmetric Standard Model

Russian Physics Journal - Decay channels of the Higgs bosons $$ H\to A\overline{f},\kern1em A\to hf\overline{f},\kern1em {H}^{\pm}\to Hf{\overline{f}}^{\hbox{'}},\kern1em {H}^{\pm}\to...     

Search for Higgs Boson in UHE Cosmic Rays

Considering the SM Higgs boson mass in the range of (95–235) GeV, we present here a mechanism for indirect searches of this scalar in UHE cosmic rays interactions. The mechanism is the decay of Higgs bosons which are produced through bubble formation due to vacuum excitation in an UHE cosmic rays interactions with air nuclei. We develop a model of hadronic interaction based on algorithms of the GENCL code of the UA5 experiment of CERN and some physics of CORSIKA code (Karlsruhe report), incorporating a fraction of energy transfer to bubble formation through vacuum excitation and subsequent multiparticle production via conversion of Higgs boson to heavy fermion pairs. Such events are expected to have high multiplicity and excess muons. This mechanism has significant effect starting from E _P 10¹⁸eV. It is found that the average muon number decreases gradually upto 175 GeV Higgs boson mass and remain practically constant thereafter for all primary energies (E _P) above 10¹⁸ eV and for all fractions of energy transfer (f _e 0.01–0.5). The fluctuation of muon multiplicity decreases with E _P and increases very slowly with Higgs mass upto 175 GeV, remaining practically invariant thereafter.     

Search for Higgs Bosons at LEP2 and Hadron Colliders

The search for the Higgs boson was one of the most relevant issues of the final years of LEP running at high energies. An excess of 3σ beyond the background expectation has been found, consistent with the production of the Higgs boson with a mass near 115 GeV/c². At the upgraded TeVatron and at LHC the search for the Higgs boson will continue. At TeVatron Higgs bosons can be detected with masses up to 180 GeV with an assumed total integrated luminosity of 20 fb^—1. LHC has the potential to discover the Higgs boson in many different decay channels for Higgs masses up to 1 TeV. It will be possible to measure Higgs boson parameters, such as mass, width, and couplings to fermions and bosons. The results from Higgs searches at LEP2 and the possibilities for searches at hadron colliders will be reviewed.     

D介子稀有衰变研究

利用工作在北京正负电子对撞机(BEPC)上的北京谱仪(BES)收集到的33pb^－1的Ψ(3770)数据,寻找D介子味道改变中性流(FCNC)和轻子数不守恒(LNV)的稀有衰变, 包括4个D⁰介子的衰变模式(K⁰e⁺e^－,Φe⁺e^－,ρ⁰e⁺e^－和K^*0e⁺e^－)和6个D⁺介子的衰变模式(K^－e⁺e⁺,K⁺e⁺e^－,π^－e⁺e⁺, π⁺e⁺e^－,K^*－e⁺e⁺和K^*+e⁺e^－). 没有发现信号,给出90%置信水平的上限. 其中, D⁺介子的两个衰变模式D⁺→K^*－e⁺e⁺和D⁺→K^*+e⁺e^－的上限是首次测量.     

Superconducting Niobium-Titanium: Enabler for Affordable MRI and the Search for the Higgs Boson

In 1961, Bell Telephone Laboratories researchers startled the world of physics by reporting that, at temperatures near absolute zero, a superconducting niobium-tin compound could support enormous electric current densities without resistance in the presence of very high magnetic fields. Suddenly, it became possible to fabricate supermagnets that generate high magnetic fields with unprecedented efficiency and economy. Scientists raced to find additional such materials and also to account theoretically for their behavior. Disregarded early on as unpromising, niobium-titanium alloys eventually emerged from among thousands of superconductors to become the most widely used, finding application in many thousands of MRI medical imaging systems and in huge particle accelerator magnets. In 1962, at Atomics International, experiments that revealed the supermagnet promise of niobium-titanium alloys also made essential contributions to the confirmation of the initially overlooked superconductivity theories of Soviet scientists Ginzburg, Landau, Abrikosov, and Gor'kov as the appropriate framework for understanding the physics of high magnetic field superconductivity.     

Study of the Standard Model Higgs Boson in the ATLAS and CMS Experiments at the LHC

Physics of Atomic Nuclei - Recent results on Higgs boson production and decays in the ATLAS and CMS experiments at the LHC are reviewed. These results are based on data accumulated from 2015 to...     

Search for Yukawa Production of a light neutral Higgs Boson at LEP

Within a Two-Higgs-Doublet Model (2HDM) a search for a light Higgs boson in the mass range of 4–12 GeV has been performed in the Yukawa process , using the data collected by the OPAL detector at LEP between 1992 and 1995 in collisions at about 91 GeV centre-of-mass energy. A likelihood selection is applied to separate background and signal. The number of observed events is in good agreement with the expected background. Within a CP-conserving 2HDM type II model the cross-section for Yukawa production depends on and for the production of the CP-odd A and the CP-even h, respectively, where is the ratio of the vacuum expectation values of the Higgs doublets and is the mixing angle between the neutral CP-even Higgs bosons. From our data 95% C.L. upper limits are derived for within the range of 8.5 to 13.6 and for between 8.2 to 13.7, depending on the mass of the Higgs boson, assuming a branching fraction into of 100%. An interpretation of the limits within a 2HDM type II model with Standard Model particle content is given. These results impose constraints on several models that have been proposed to explain the recent BNL measurement of the muon anomalous magnetic moment. Received: 1 November 2001 / Published online: 22 February 2002     

Decays of H(h; A) Higgs Bosons into Two Photons (Gluons)

Russian Physics Journal - Within the framework of the Minimal Supersymmetric Standard Model, we have investigated decay channels of Higgs bosons into circularly polarized photons (gluons): H(h; A)...     

Decays of the Weinberg-Salam Higgs particle in models with two Higgs doublets

In a class of extended Higgs structures containing two Higgs doublets, the decays of the Weinberg-Salam Higgs particle might be significantly different from those in the standard model because it has large branching ratios to decay into light Higgs bosons. We discuss the decays of the Weinberg-Salam Higgs particle with mass range from 7 GeV up to 1 TeV.     

Decays of Z Bosons into Triple-Quark and Double-Quark Structures

This paper presents a mechanism of decay of elementary particles, which has been developed based on a new approach. The results obtained may be of interest to experimenters engaged in the decay of Z ⁰ bosons. Schemes and modes of the structural decay of gamma structures, one of which is the Z ⁰ boson, are given. Analysis of the schemes and modes of the structural decay has shown that the decays of the product triple-quark particles (products of the decay of a Z ⁰ boson into triple-quark particles) result in the occurrence of a new mode of decay – the decay of one triple-quark particle into three triple-quark particles. According to the proposed mechanism of the decay of particles, an electron, a muon, a triton, and a gamma photon are particles consisting of a quark–antiquark pair and having a spin equal to unity.     

Search for neutral supersymmetric Higgs Bosons in multijet events at sqrt[s]=1.96 TeV

We have performed a search for neutral Higgs bosons produced in association with bottom quarks in pp collisions, using 260 pb-1 of data collected with the D0 detector in Run II of the Fermilab Tevatron Collider. 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 tanbeta. 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.     

Search for very light CP-odd Higgs Boson in radiative decays of Upsilon(1S)

We search for a non-SM-like CP-odd Higgs boson (a(1)(0)) decaying to tau(+)tau(-) or mu(+)mu(-) in radiative decays of the Upsilon(1S). No significant signal is found, and upper limits on the product branching ratios are set. Our tau(+)tau(-) results are almost 2 orders of magnitude more stringent than previous upper limits. Our data provide no evidence for a Higgs state with a mass of 214 MeV decaying to mu(+)mu(-), previously proposed as an explanation for 3 Sigma(+)-->pmu(+)mu(-) events observed by the HyperCP experiment. Our results constrain NMSSM models.     

Single Boson Realizations of the Higgs Algebra

We obtained for the Higgs algebra three kinds of single boson realizations such as the unitary Holstein-Primakoff-like realization, the non-unitary Dyson-like realization, and the unitary Villain-like realization. The corre-sponding similarity transformations between the Holstein-Primakoff-like realizations and the Dyson-like realizations are given.