Oblique parameters in gauged baryon and lepton numbers with a 125 GeV Higgs

In an extension of the standard model, where baryon number and lepton number are local gauge sym- metries, we analyze the effect of corrections from exotic fermions and scalars on the oblique parameters S, T, U. Because a light neutral Higgs h0 with mass around 12-126 GeV strongly constrains the corresponding parameter space of this model, we also investigate the gluon fusion process gg→h0 and two photon decay of the lightest neutral Higgs h0→yy at the Large Hadron Collider.     

t →cγ and t →cg in Local Gauged Baryon and Lepton Numbers

In this paper, we calculate the top quark rare decays t →cγ and v in an extension of the standard model, where baryon number and lepton number are local gauge symmetries. Adopting reasonable assumptions on the parameter space, we find that the branching ratios of t →cγ and t →cg can reach 10^-6 and 10^-5 respectively, which can be detected in near future.     

New Electroweak Model Without a Higgs Particle

A new unified electroweak model is proposed in this paper. In this unified electroweak model, Higgsmechanism is not used, so no Higgs particle exists in the model. In order to keep the masses of intermediate gaugebosons non-zero, two sets of gauge fields will be introduced. In order to introduce symmetry breaking and to help tointroduce the masses of all fields, a vacuum potential is needed. Except for those terms concerning Higgs particle, thefundamental dynamical properties of this model are similar to those of the standard model. And in a proper limit, thismodel will approximately return to the standard model. The purpose of this paper is not to say that the Higgs particledoes not exist in Nature, it is only to prove that, without a Higgs particle, we can also set up a unified electroweak modelwhich is consistent with present experiments.     

Neutrino Mixing in the BLMSSM

Abstract In recent years, a nonzero value for the neutrino mixing angle θ13 has been successively measured by the international famous reactor oscillation experiments, which is greater than 5 standard deviations. Our study is in the framework of the MSSM, where baryon and lepton numbers are local gauged symmetries （BLMSSM）. This model can generate three tiny neutrino masses at the tree level through TeV scale seesaw mechanism. In our paper, we analyze the neutrino masses and their corresponding mixing angles with a ＂top-down＂ method, assuming neutrino mass spectrum with normal ordering （NO） and inverted ordering （IO）.     

Charmed baryon heavy-quark resonances with symmetry

We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as Ac（2595）, Ac（2660）, Ec（2902） or Ac（2941）, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU（4） schemes.     

Charmed baryon resonances with heavy-quark symmetry

We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with exper-imental observations, such as Λ_c(2595), Λ_c(2660), Σ_c(2902) or Λ_c(2941), while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU(4) schemes.     

Littlest Higgs Model and Higgs Boson Associated Production with Top Quark Pair at High Energy Linear e+e- Collider

In the parameter space allowed by the electroweak precision measurement data, we consider the contributions of the new particles predicted by the littlest Higgs model to the Higgs boson associated production with top quark pair in the future high energy linear e⁺e^- collider (ILC). We find that the contributions mainly come from the new gauge bosons Z_H and B_H. For reasonable values of the free parameters, the absolute value of the relative correction parameter δσ/σ^SM can be significanly large, which might be observed in the future ILC experiment with √{S}=800 GeV.     

Two Higgs bi-doublet left-right model with spontaneous P and CP violation

A left-right symmetric model with two Higgs bi-doublet is shown to be a consistent model for both spontaneous P and CP violation. The flavor changing neutral currents can be suppressed by the mechanism of approximate global U(1) family symmetry. The constraints from neural K meson mass difference Δm _K are calculated and it is demonstrated that a right-handed gauge boson W ₂ contribution in box-diagrams with mass well below 1 TeV is allowed due to a cancelation caused by a light-charged Higgs boson with a mass range of 150–300 GeV. The W ₂ contribution to ε _K can be suppressed from an appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa matrix. The model is also found to be fully consistent with B ⁰ mass difference Δm _B and the mixing induced CP violation sin2β _{J/ Ψ}, which is usually difficult for the model with only one Higgs bi-doublet. The new physics beyond the standard model can be directly searched at the colliders LHC and ILC. Supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 10475105 and 10491306) and the Key Project of Chinese Academy of Sciences (CAS)     

Higgs Algebraic Symmetry of Screened System in a Spherical Geometry

The orbits and the dynamical symmetries for the screened Coulomb potentials and isotropic harmonic oscillators have been studied by Wu and Zeng[Z.B.Wu and J.Y.Zeng,Phys.Rev.A 62(2000)032509].We find similar properties in the corresponding systems in a spherical space,whose dynamical symmetries are described by Higgs algebra.There exist extended Runge-Lenz vector for screened Coulomb potentials and extended quadruple tensor for screened harmonic oscillators.They,together with angular momentum,constitute the generators of the geometrical symmetry group.Moreover,there exist an infinite number of closed orbits for suitable angular momentum values,and we give the equations of the classical orbits.The eigenenergy spectrum and corresponding eigenstates in these systems are derived.     

Selected topics in Higgs physics at the LHC

In this talk I discuss a few selected topics in Higgs phenomenology at the LHC. After some brief remarks on the standard model Higgs I turn to more novel possibilities, discussing a heavy Higgs scenario, a light Higgs scenario and a no Higgs scenario. In the case of the light Higgs, I discuss briefly the physics opportunities afforded if it becomes possible to detect low angle scattered protons at the LHC.     

Higgs Algebraic Symmetry of Screened System in a Spherical Geometry

The orbits and the dynamical symmetries for the screened Coulomb potentials and isotropic harmonic oscillators have been studied by Wu and Zeng [Z.B. Wu and J.Y. Zeng, Phys. Rev. A 62 (2000) 032509]. We find similar properties in the corresponding systems in a spherical space, whose dynamical symmetries are described by Higgs algebra. There exist extended Runge-Lenz vector for screened Coulomb potentials and extended quadruple tensor for screened harmonic oscillators. They, together with angular momentum, constitute the generators of the geometrical symmetry group. Moreover, there exist an infinite number of closed orbits for suitable angular momentum values, and we give the equations of the classical orbits. The eigenenergy spectrum and corresponding eigenstates in these systems are derived.     

Production and decay of the 125 GeV Higgs boson in thelittlest Higgs model with T-parity

Motivated by recent search results for the standard model (SM) Higgs boson at the Large Hadron Collider (LHC), we revisit the Higgs phenomenology in the littlest Higgs model with T-parity (LHT). We present the signal strength modifier μ, respectively, for the main search channels qq' → jjh→ jjγγ, qq'→ Vh→ Vγγ, qq'→ Vh → Vbb, gg→ h → γγ, and gg → h → VV in the LHT model. It is found that an enhancement factor of 1.09-1.56 in the qq' → jjh→ jjγγ channel can be obtained for this model in Case B with parameter f in the range 500-1000~GeV. However, the rates for bb, ττ are significantly suppressed relative to the SM predictions, which are still consistent with the current sensitivity. It is hoped that this will be further tested with larger integrated luminosity at the LHC.     

Littlest Higgs模型中通过e^+e^-对撞研究新规范玻色子B_H与SM中规范玻色子的伴随产生过程

计划中的高能量、高亮度对撞机ILC在寻找新物理模型所预言的新的重粒子方面具有很大的潜力。本文,我们研究了在ILC上,通过过程e^+e^- ->r(Z)B_H发现littlest Higgs模型中最轻的新规范玻色子B_H的可能性。结果显示,在较大的参数空间范围,这两个过程都有较大的产生截面,能产生足够的信号探测B_H,尤其是对过程e^+e^- ->rB_H。另外,B_H的一些衰变道可以产生特征比较明显背景比较干净的信号。如果B_H存在,随着ILC的运行,新的规范玻色子B_H应能通过这两过程观测。     

Super-light baryo-photons,weak gravity conjecture and exotic instantons in neutron-antineutron transitions

In companion papers(A. Addazi, Nuovo Cim. C, 38(1): 21(2015); A. Addazi, Z. Berezhiani, and Y. Kamyshkov, ar Xiv:1607.00348), we have discussed current bounds on a new super-light baryo-photon, associated with a U(1)B-L gauge, from current neutron-antineutron data, which are competitive with E¨otv¨os-type experiments.Here, we discuss the implications of possible baryo-photon detection in string theory and quantum gravity. The discovery of a very light gauge boson should imply violation of the weak gravity conjecture, carrying deep consequences for our understanding of holography, quantum gravity and black holes. We also show how the detection of a baryophoton would exclude the generation of all B-L violating operators from exotic stringy instantons. We will argue against the common statement in the literature that neutron-antineutron data may indirectly test at least the 300-1000 Te V scale. Searches for baryo-photons can provide indirect information on the Planck(or string) scale(quantum black holes, holography and non-perturbative stringy effects). This strongly motivates new neutron-antineutron experiments with adjustable magnetic fields dedicated to the detection of super-light baryo-photons.     

Higgs and Bottom Quarks Associated Production at High Energy Colliders in the Littlest Higgs Model with T-Parity

In the littlest Higgs Model with T-parity,we discuss the Higgs production in association with bottom quarks at the LHC and future electron-positron collider.We calculate the cross sections of production channels pp→bb H,bb→H and bg→b H at 14 Te V LHC and the cross sections of production channel e~+e~-→bb H in(un)polarized beams at the lowest order.In order to investigate the observability,we display some typical final state distributions in the Higgs to diphoton channel.     

Single Production of Charged Gauge Boson WH^- from Left-Right Twin Higgs Model in Association with Top Quark at LHC

The twin Higgs mechanism has recently been proposed to solve the little hierarchy problem. In the context of the left-right twin Higgs （LRTH） model, we discuss single production of the new charged gauge boson WH^- , which is predicted by the left-right twin Higgs model, in association with top quark at the CERN Large Hadron Collider （LHC）. It is found that, for a typical nonzero value of mass mixing parameter M = 150 GeV in the LRTH model, the production cross section is in the range of 3 ×10^-2 - 6.07×10^3 fb at the LHC. As long as the WH^- is not too heavy, the possible signatures of the heavy charged gauge boson might be detected at the LHC experiments.     

A quark model study of semileptonic baryon decays in the electronic decay modes

A relativistic quark model based on Dirac equation with the independent-quark confining potential of the form (1 +γ ⁰)[a ln(r/b)] is used to compute the weak electric and magnetic form factors for semileptonic baryonic decays in the electronic decay modes. The values obtained for (g ₂/g ₁) agree with the non relativistic results and those for (f ₂/f ₁) agree with the MIT bag model values of Donoghue and Holstein. The SU(3) symmetry breaking does not generate appreciable departures in (f ₂/f ₁) values from corresponding Cabibbo values.     

From two mesons and (V-A) weak currents to the standard model of quark and lepton interactions

This retrospective paper traces the conceptual evolution of two theories in which the author was involved—the two-meson theory (with H A Bethe) in 1947 and the universal (V-A) theory of weak interactions (with E C G Sudarshan) in 1957—into the present-day standard model of particle interactions. Part 1 is entitled ‘From the pion to QCD and pseudo-Goldstone bosons” and Part 2 “From the muon and neutrino to QFD and chiral anomalies’. Adapted from two lectures delivered at the University of Rochester in October, 1987.