scholarly journals Diphoton decay of the Higgs boson and new bound states of top and antitop quarks

2015 ◽  
Vol 30 (21) ◽  
pp. 1550132 ◽  
Author(s):  
C. D. Froggatt ◽  
C. R. Das ◽  
L. V. Laperashvili ◽  
H. B. Nielsen
Keyword(s):  
Higgs Boson ◽  
Excited States ◽  
Atomic Physics ◽  
Bound States ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Bound State ◽  
Sigma Level ◽  
Gluon Production ◽  
State Formula

We consider the constraints, provided by the LHC results on Higgs boson decay into 2 photons and its production via gluon fusion, on the previously proposed Standard Model (SM) strongly bound state S of six top quarks and six antitop quarks. A correlation is predicted between the ratios [Formula: see text] and [Formula: see text] of the Higgs diphoton decay and gluon production amplitudes, respectively to their SM values. We estimate the contribution to these amplitudes from one-loop diagrams involving the 12 quark bound state S and related excited states using an atomic physics based model. We find two regions of parameter space consistent with the ATLAS and CMS data on [Formula: see text] at the three sigma level: a region close to the SM values [Formula: see text] with the mass of the bound state [Formula: see text][Formula: see text]GeV and a region with [Formula: see text] corresponding to a bound state mass of [Formula: see text][Formula: see text]GeV.

ENERGY SPECTRA OF GLUINONIUM

2011 ◽  
Vol 20 (supp02) ◽  
pp. 200-209
Author(s):  
CÉSAR A. Z. VASCONCELLOS ◽  
DIMITER HADJIMICHEF ◽  
MÁRIO L. L. DA SILVA ◽  
MOISÉS RAZEIRA ◽  
ALEXANDRE MESQUITA ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Excited States ◽  
Bound States ◽  
Bound State ◽  
State Equation ◽  
Relativistic Case ◽  
Light Scalar ◽  
Pseudo Scalar ◽  
Relativistic Bound States

We investigate relativistic bound states for a hypothetical light scalar gluino pair (gluinonium), in the framework of the covariant Bethe-Salpeter equation (BSE). In this paper, we derive, from the covariant BSE for a fermion-anti-fermion system, using charge conjugation, the corresponding bound-state equation for a gluino pair and we then formulate, for a static harmonic kernel, the coupled differential equations for the corresponding static Bethe-Salpeter amplitude. The steps of our approach then include a numerical solution of the Bethe-Salpeter amplitude for a two-body interaction consisting of scalar, pseudo-scalar, and four-vector components and the determination of the energy spectrum for the ground and the radially excited states of massive gluinonium. We found the energy spectrum and radial distributions of fundamental and excited states of gluinonium. The comparison of the values obtained in the extreme relativistic case with the corresponding values predicted by a harmonic oscillator potential model shows that there is good agreement between the two formulations. The predictions of the binding energy of glunionium in the non-relativistic model are however systematically higher.

scholarly journals The second lightest CP-even Higgs boson signals in the NMSSM at the LHC

2018 ◽  
Vol 33 (10) ◽  
pp. 1850071
Author(s):  
M. M. Almarashi
Keyword(s):  
Higgs Boson ◽  
Parameter Space ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Bottom Quarks ◽  
Final States ◽  
Production Rates ◽  
Decay Channels ◽  
Text Signals

We study the signal rates of the second lightest CP-even Higgs boson, [Formula: see text], of the NMSSM produced in gluon fusion, in association with bottom quarks and in association with top quarks, which is not the SM-like Higgs boson, at the LHC. We evaluate the production rates of [Formula: see text] in the SM fermionic and bosonic final states in addition to [Formula: see text], [Formula: see text] and [Formula: see text] final states. It is observed that the size of the signal rates in some regions of the NMSSM parameter space is quite large and that could help extracting [Formula: see text] signals at the LHC through a variety of decay channels.

Quantum field theory of bound states IV. Relativistic theory of the excited states of hydrogen

1953 ◽  
Vol 219 (1139) ◽  
pp. 516-526 ◽  
Keyword(s):  
Excited States ◽  
Lamb Shift ◽  
Bound States ◽  
Bound State ◽  
Crossing Over ◽  
Quantum Field ◽  
Coupled Equations ◽  
First Approximation ◽  
Single Integral ◽  
The Difference

When allowance is made for the instability of the excited states of hydrogen it is necessary to replace the equation of Salpeter & Bethe (1951) by a set of coupled integral equations for representatives of the state vector. These representatives correspond to an electron-proton bound state and also to the electron and proton with any number of photons present. The coupled equations can be reduced to a single integral equation, which gives the electronproton bound state as an eigenstate of a modified propagator. The modified propagator is related to the two-body propagator of Salpeter & Bethe. The difference between the first approximation to the modified propagator and the first approximation to the two-body compound propagator (Eden 1952, 1953) can be represented by a displacement of its singularity in total energy-momentum space. This displacement gives in a relativistic form all the relevant contributions to the Lamb shift to this order; these include the contribution from low-energy transverse photons crossing over an arbitrary number of longitudinal photons; previously this term has always been deduced by physical arguments and obtained by non-relativistic methods (Bethe 1947; Salpeter 1952). The displacement of the singularity also gives decay coefficients to this order in the charge. The method can readily be extended to higher approximations.

scholarly journals NEW BOUND STATES OF HEAVY QUARKS AT LHC AND TEVATRON

2011 ◽  
Vol 26 (15) ◽  
pp. 2503-2521 ◽  
Author(s):  
C. R. DAS ◽  
C. D. FROGGATT ◽  
L. V. LAPERASHVILI ◽  
H. B. NIELSEN
Keyword(s):  
Top Quark ◽  
Bound States ◽  
Form Factors ◽  
Top Quarks ◽  
Bound State ◽  
Heavy Quarks ◽  
Fourth Generation ◽  
Charge Multiplicity ◽  
The Masses ◽  
B Quark

The present paper is based on the assumption that heavy quarks bound states exist in the Standard Model (SM). Considering New Bound States (NBS) of top–antitop quarks (named T-balls) we have shown that: (1) there exists the scalar 1S-bound state of [Formula: see text]; (2) the forces which bind the top-quarks are very strong and almost completely compensate the mass of the twelve top–antitop-quarks in the scalar NBS; (3) such strong forces are produced by the Higgs–top-quarks interaction with a large value of the top-quark Yukawa coupling constant gt≃1. Theory also predicts the existence of the NBS [Formula: see text], which is a color triplet and a fermion similar to the t'-quark of the fourth generation. We have also considered the "b-quark-replaced" NBS, estimated the masses of the lightest fermionic NBS: M NBS ≳300 GeV , and discussed the larger masses of T-balls. We have developed a theory of the scalar T-ball's condensate and predicted the existence of three SM phases. Searching for heavy quark bound states at the Tevatron and LHC is discussed. We have constructed the possible form-factors of T-balls, and estimated the charge multiplicity coming from the T-ball's decays.

scholarly journals Tetraquark state X(6900) and the interaction between diquark and antidiquark

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Hong-Wei Ke ◽  
Xin Han ◽  
Xiao-Hai Liu ◽  
Yan-Liang Shi
Keyword(s):  
Excited States ◽  
Bound States ◽  
Effective Interaction ◽  
Axial Vector ◽  
Bound State ◽  
Tetraquark State ◽  
Effective Coupling ◽  
Final State ◽  
Interaction Kernel ◽  
Quantum Numbers

AbstractRecently LHCb declared a new structure X(6900) in the final state di-$$J/\psi $$ J / ψ which is popularly regarded as a cc-$$\bar{c}\bar{c}$$ c ¯ c ¯ tetraquark state. Within the Bethe–Salpeter (B–S) framework we study the possible cc-$$\bar{c}\bar{c}$$ c ¯ c ¯ bound states and the interaction between diquark (cc) and antidiquark ($$\bar{c}\bar{c}$$ c ¯ c ¯ ). In this work cc ($$\bar{c}\bar{c}$$ c ¯ c ¯ ) is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of cc-$$\bar{c}\bar{c}$$ c ¯ c ¯ bound state are $$0^+$$ 0 + , $$1^+$$ 1 + and $$2^+$$ 2 + . Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for the diquark and antidiquark system. Then we deduce the B–S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of X(6900) when we assign appropriate values for parameter $$\kappa $$ κ introduced in the interaction (kernel). We also briefly calculate the spectra of bb-$$\bar{b}\bar{b}$$ b ¯ b ¯ bound states. Future measurement of bb-$$\bar{b}\bar{b}$$ b ¯ b ¯ state will help us to determine the exact form of effective interaction.

scholarly journals DECAYS OF FOURTH GENERATION BOUND STATES

2012 ◽  
Vol 27 (30) ◽  
pp. 1250179
Author(s):  
V. F. DMITRIEV ◽  
V. V. FLAMBAUM
Keyword(s):  
Higgs Boson ◽  
Binding Energy ◽  
Decay Mode ◽  
Bound States ◽  
Bound State ◽  
Fourth Generation ◽  
Exchange Potential ◽  
Total Width ◽  
Decay Modes ◽  
Boson Exchange

We consider the decay modes of the heavy [Formula: see text] bound states originating from Higgs boson exchange between quark–antiquark pair. In case of a small coupling between the fourth and lower generation the main decay mode is [Formula: see text] annihilation. We show that for a vector state the dominant decay modes are Higgs-gamma and Higgs-Z decays, while for a pseudoscalar state the strong two-gluon decay mode dominates. The bound states are very narrow. The ratio of the total width to the binding energy is less than 1% if we are not extremely close to the critical quark mass where the binding energy is very small. The discussed decay modes exist for any fermion–antifermion bound states including heavy leptons and heavy neutrinos if their masses are high enough to form a bound state due to attractive Higgs boson exchange potential.

scholarly journals Boosting invisible Higgs boson searches by tagging a gluon jet for the gluon fusion process

2020 ◽  
Vol 102 (11) ◽  
Author(s):  
Won Sang Cho ◽  
Hyung Do Kim ◽  
Dongsub Lee
Keyword(s):  
Higgs Boson ◽  
Gluon Fusion ◽  
Fusion Process

scholarly journals ZH production in gluon fusion: two-loop amplitudes with full top quark mass dependence

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Long Chen ◽  
Gudrun Heinrich ◽  
Stephen P. Jones ◽  
Matthias Kerner ◽  
Jonas Klappert ◽  
...  
Keyword(s):  
Top Quark ◽  
Quark Mass ◽  
Gluon Fusion ◽  
Top Quarks ◽  
Mass Dependence ◽  
Finite Part ◽  
Top Quark Mass ◽  
Helicity Amplitudes ◽  
Quark Mass Dependence ◽  
Loop Amplitudes

Abstract We present results for the two-loop helicity amplitudes entering the NLO QCD corrections to the production of a Higgs boson in association with a Z -boson in gluon fusion. The two-loop integrals, involving massive top quarks, are calculated numerically. Results for the interference of the finite part of the two-loop amplitudes with the Born amplitude are shown as a function of the two kinematic invariants on which the amplitudes depend.

scholarly journals Bound states of a Klein–Gordon particle in the presence of a smooth potential well

2020 ◽  
Vol 35 (23) ◽  
pp. 2050140
Author(s):  
Eduardo López ◽  
Clara Rojas
Keyword(s):  
Bound States ◽  
Gordon Equation ◽  
Bound State ◽  
Potential Well ◽  
One Dimensional ◽  
Smooth Potential ◽  
Klein Gordon ◽  
The One ◽  
Potential Parameters ◽  
Klein Gordon Equation

We solve the one-dimensional time-independent Klein–Gordon equation in the presence of a smooth potential well. The bound state solutions are given in terms of the Whittaker [Formula: see text] function, and the antiparticle bound state is discussed in terms of potential parameters.

RETARDATION EFFECTS IN COVARIANT THREE-DIMENSIONAL BOUND STATE WAVE FUNCTIONS

2005 ◽  
Vol 14 (06) ◽  
pp. 931-947 ◽  
Author(s):  
F. PILOTTO ◽  
M. DILLIG
Keyword(s):  
Bound States ◽  
Three Dimensional ◽  
Bound State ◽  
Relative Energy ◽  
Wave Functions ◽  
Three Dimensions ◽  
State Wave ◽  
Scalar Diquark ◽  
Bound State Wave Function ◽  
Retardation Effects

We investigate the influence of retardation effects on covariant 3-dimensional wave functions for bound hadrons. Within a quark-(scalar) diquark representation of a baryon, the four-dimensional Bethe–Salpeter equation is solved for a 1-rank separable kernel which simulates Coulombic attraction and confinement. We project the manifestly covariant bound state wave function into three dimensions upon integrating out the non-static energy dependence and compare it with solutions of three-dimensional quasi-potential equations obtained from different kinematical projections on the relative energy variable. We find that for long-range interactions, as characteristic in QCD, retardation effects in bound states are of crucial importance.

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