scholarly journals On a possibility of a consistent interpretation of diboson excesses at LHC

2016 ◽  
Vol 31 (26) ◽  
pp. 1650144
Author(s):  
Boris A. Arbuzov ◽  
Ivan V. Zaitsev
Keyword(s):  
Isotopic Spin ◽  
Spontaneous Generation ◽  
Coupling Constant ◽  
Triple Interaction ◽  
Decay Channels ◽  
Atlas Data ◽  
Scalar State ◽  
Spin Resonances

Recently reported diboson and diphoton excesses at LHC are interpreted to be connected with heavy WW zero spin resonances. The resonances appears due to the would-be anomalous triple interaction of the weak bosons, which is defined by well-known coupling constant [Formula: see text]. The 2 TeV anomaly, tentatively corresponds to weak isotopic spin-2 scalar state and the [Formula: see text] 750 GeV anomaly corresponds to weak isotopic spin-0 pseudoscalar state. We obtain estimates for the effect, which qualitatively agree with ATLAS data. Effects are predicted in a production of W[Formula: see text] W[Formula: see text], (Z, [Formula: see text])(Z, [Formula: see text]) via resonance [Formula: see text] with [Formula: see text] 750 GeV, which could be reliably checked at the upgraded LHC at [Formula: see text] 13 TeV. In the framework of an approach to the spontaneous generation of the triple anomalous interaction its coupling constant is estimated to be [Formula: see text] in an agreement with existing restrictions. Specific predictions of the hypothesis are significant effects in decay channels [Formula: see text], [Formula: see text].

ATLAS diboson excesses as an evidence for a heavy WW resonance with the weak isospin 2

2015 ◽  
Vol 30 (36) ◽  
pp. 1550221 ◽  
Author(s):  
Boris A. Arbuzov ◽  
Ivan V. Zaitsev
Keyword(s):  
Inclusive Production ◽  
Spontaneous Generation ◽  
Atlas Data

Recently reported diboson excesses at LHC are interpreted as indications for heavy resonance with weak isospin 2 due to would-be anomalous interaction of the weak bosons, which is defined by a constant [Formula: see text]. In the framework of an approach to the spontaneous generation of such interaction, we obtain estimates for the effect, which qualitatively agrees with ATLAS data. Effects are predicted in inclusive production of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] resonances in the vicinity of [Formula: see text], which could be reliably checked at the upgraded LHC with [Formula: see text].

scholarly journals Measurement of $$W^{\pm }$$-boson and Z-boson production cross-sections in pp collisions at $$\sqrt{s}=2.76$$ TeV with the ATLAS detector

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Cross Sections ◽  
Z Boson ◽  
Production Cross ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Decay Channels ◽  
Atlas Data ◽  
Full Phase Space ◽  
Systematic Uncertainties ◽  
Detector Acceptance

Abstract The production cross-sections for $$W^{\pm }$$W± and Z bosons are measured using ATLAS data corresponding to an integrated luminosity of 4.0 pb$$^{-1}$$-1 collected at a centre-of-mass energy $$\sqrt{s}=2.76$$s=2.76 TeV. The decay channels $$W \rightarrow \ell \nu $$W→ℓν and $$Z \rightarrow \ell \ell $$Z→ℓℓ are used, where $$\ell $$ℓ can be an electron or a muon. The cross-sections are presented for a fiducial region defined by the detector acceptance and are also extrapolated to the full phase space for the total inclusive production cross-section. The combined (average) total inclusive cross-sections for the electron and muon channels are: $$\begin{aligned} \sigma ^{\text {tot}}_{W^{+}\rightarrow \ell \nu }= & {} 2312 \pm 26\ (\text {stat.})\\&\pm 27\ (\text {syst.}) \pm 72\ (\text {lumi.}) \pm 30\ (\text {extr.})~\text {pb} , \\ \sigma ^{\text {tot}}_{W^{-}\rightarrow \ell \nu }= & {} 1399 \pm 21\ (\text {stat.})\ \pm 17\ (\text {syst.}) \\&\pm 43\ (\text {lumi.}) \pm 21\ (\text {extr.})~\text {pb} , \\ \sigma ^{\text {tot}}_{Z \rightarrow \ell \ell }= & {} 323.4 \pm 9.8\ (\text {stat.}) \pm 5.0\ (\text {syst.})\\&\pm 10.0\ (\text {lumi.}) \pm 5.5 (\text {extr.}) ~\text {pb} . \end{aligned}$$σW+→ℓνtot=2312±26(stat.)±27(syst.)±72(lumi.)±30(extr.)pb,σW-→ℓνtot=1399±21(stat.)±17(syst.)±43(lumi.)±21(extr.)pb,σZ→ℓℓtot=323.4±9.8(stat.)±5.0(syst.)±10.0(lumi.)±5.5(extr.)pb.Measured ratios and asymmetries constructed using these cross-sections are also presented. These observables benefit from full or partial cancellation of many systematic uncertainties that are correlated between the different measurements.

IMPLICATIONS OF A LARGE $Ht \bar{t}$-COUPLING FOR THREE-BODY DECAYS OF HIGGS BOSON AND TOP QUARK

1991 ◽  
Vol 06 (38) ◽  
pp. 3491-3497 ◽  
Author(s):  
R. DECKER ◽  
M. NOWAKOWSKI ◽  
A. PILAFTSIS
Keyword(s):  
Top Quark ◽  
Branching Ratios ◽  
Higgs Particle ◽  
Coupling Constant ◽  
Decay Channels ◽  
The Standard Model ◽  
The Common ◽  
The Masses ◽  
Three Body ◽  
O 10

The three-body decays a heavy Higgs [Formula: see text], [Formula: see text] and of a heavy top t → bW+ H are studied in the context of the Standard Model. The common feature of these decay channels is the relative big coupling constant of the Higgs particle to the top quark. Indeed within a certain range of the masses M H , mt we find that branching ratios of the order O(10-3) are possible for the decays [Formula: see text] and t → bW+ H. The decay with [Formula: see text] as a function of M H and mt is investigated below the 2mt threshold (Mtt < 2mt) and is found to have an interesting behaviour just near this threshold.

Uniqueness of solutions of the Bethe─Salpeter equation for scattering

1956 ◽  
Vol 237 (1211) ◽  
pp. 496-512 ◽  
Keyword(s):  
Integral Equation ◽  
Angular Momentum ◽  
Singular Integral Equation ◽  
Singular Integral ◽  
Nucleon Nucleon ◽  
Isotopic Spin ◽  
Coupling Constant ◽  
Uniqueness Of Solutions ◽  
Nucleon Scattering ◽  
Range Of Values

The Bethe-Salpeter equation for nucleon-nucleon scattering is a singular integral equation, and it is therefore not certain that a unique solution exists. It is shown that the equation is soluble for states of all angular momentum, parity and isotopic spin if, and only if, g 2 /4 π is less than 1/6 π . The range of values of g for which there exist solutions of a particular angular momentum and parity is given. The Bethe-Salpeter equation for meson-nucleon scattering is also examined. In this case, the equation is soluble for all values of the coupling constant, but the solution, regarded as a function of g , will exhibit discontinuities when g passes through certain values.

scholarly journals PROPAGATOR POLES AND AN EMERGENT STABLE STATE BELOW THRESHOLD: GENERAL DISCUSSION AND THE E(38) STATE

2012 ◽  
Vol 27 (39) ◽  
pp. 1250229 ◽  
Author(s):  
FRANCESCO GIACOSA ◽  
THOMAS WOLKANOWSKI
Keyword(s):  
Numerical Study ◽  
Stable State ◽  
Scalar Particle ◽  
Riemann Sheet ◽  
Coupling Constant ◽  
Scalar State ◽  
Simple Quantum ◽  
Pion Threshold ◽  
Order Of Magnitude ◽  
Pseudo Scalar

In the framework of a simple quantum field theory describing the decay of a scalar state into two (pseudo)scalar ones we study the pole(s) motion(s) of its propagator: besides the expected pole on the second Riemann sheet, we find — for a large enough coupling constant — a second, additional pole on the first Riemann sheet below threshold, which corresponds to a stable state. We then perform a numerical study for a hadronic system in which a scalar particle couples to pions. We investigate under which conditions a stable state below the two-pion threshold can emerge. In particular, we study the case in which this stable state has a mass of 38 MeV, which corresponds to the recently claimed novel scalar state E(38). Moreover, we also show that the resonance f0(500) and the stable state E(38) could be two different manifestations of the same "object". Finally, we also estimate the order of magnitude of its coupling to photons.

Exchange-Correlation Energy Densities and Response Potentials: Connection Between Two Definitions and Analytical Model for the Strong-Coupling Limit of a Stretched Bond

2019 ◽  
Author(s):  
S. Giarrusso ◽  
Paola Gori-Giorgi
Keyword(s):  
Density Functional Theory ◽  
Strong Coupling ◽  
Density Functional ◽  
Correlation Energy ◽  
Order Term ◽  
Strong Coupling Limit ◽  
Local Form ◽  
Coupling Constant ◽  
Functional Theory ◽  
Exchange Correlation

We analyze in depth two widely used definitions (from the theory of conditional probablity amplitudes and from the adiabatic connection formalism) of the exchange-correlation energy density and of the response potential of Kohn-Sham density functional theory. We introduce a local form of the coupling-constant-dependent Hohenberg-Kohn functional, showing that the difference between the two definitions is due to a corresponding local first-order term in the coupling constant, which disappears globally (when integrated over all space), but not locally. We also design an analytic representation for the response potential in the strong-coupling limit of density functional theory for a model single stretched bond.<br>

Assessing the Calculation of Exchange Coupling Constants and Spin Crossover Gaps Using the Approximate Projection Model to Improve Density Function Calculations

2019 ◽  
Author(s):  
Xianghai Sheng ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Exchange Coupling ◽  
Density Functional ◽  
Spin Crossover ◽  
Coupling Constants ◽  
Spin Projection ◽  
Coupling Constant ◽  
Projection Model ◽  
Functional Theory

This work evaluates the quality of exchange coupling constant and spin crossover gap calculations using density functional theory corrected by the Approximate Projection model. Results show that improvements using the Approximate Projection model range from modest to significant. This study demonstrates that, at least for the class of systems examined here, spin-projection generally improves the quality of density functional theory calculations of J-coupling constants and spin crossover gaps. Furthermore, it is shown that spin-projection can be important for both geometry optimization and energy evaluations. The Approximate Project model provides an affordable and practical approach for effectively correcting spin-contamination errors in molecular exchange coupling constant and spin crossover gap calculations.

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