scholarly journals Exotic diboson $$Z'$$ decays in the U$$\mu \nu $$SSM

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
J. A. Aguilar-Saavedra ◽  
I. Lara ◽  
D. E. López-Fogliani ◽  
C. Muñoz
Keyword(s):  
Standard Model ◽  
Top Quarks ◽  
High Energy ◽  
Large Radius ◽  
Decay Modes ◽  
Z Decays ◽  
The Standard Model

AbstractSearches for new leptophobic resonances at high energy colliders usually target their decay modes into pairs of light quarks, top quarks, or standard model bosons. Additional decay modes may also be present, producing signatures to which current searches are not sensitive. We investigate the performance of generic searches that look for resonances decaying into two large-radius jets. As benchmark for our analysis we use a supersymmetric $$\text {U}(1)'$$ U ( 1 ) ′ extension of the Standard Model, the so-called U$$\mu \nu $$ μ ν SSM, where all the SM decay modes of the $$Z'$$ Z ′ boson take place, plus additional (cascade) decays into new scalars. The generic searches use a generic multi-pronged jet tagger and take advantage of the presence of b quarks in the large-radius jets, and are sensitive to all these $$Z'$$ Z ′ decay modes (except into light quarks) at once. For couplings that are well below current experimental constraints, these generic searches are sensitive at the $$3\sigma -4\sigma $$ 3 σ - 4 σ level with Run 2 LHC data.

MEASURING THE $H t\bar t$ COUPLING IN e+e− COLLISIONS

1992 ◽  
Vol 07 (19) ◽  
pp. 1765-1769 ◽  
Author(s):  
A. DJOUADI ◽  
J. KALINOWSKI ◽  
P.M. ZERWAS
Keyword(s):  
Standard Model ◽  
Top Quark ◽  
Top Quarks ◽  
Mass Range ◽  
High Energy ◽  
Fundamental Parameter ◽  
Quark Coupling ◽  
The Standard Model

Higgs radiation off heavy top quarks in high-energy e+e− colliders may be exploited to measure the Higgs-top quark coupling. We explore the mass range for which the process [Formula: see text] provides access to this fundamental parameter in the Standard Model.

scholarly journals Planck Neutrinos as Ultra High Energy Cosmic Rays

2020 ◽  
Vol 29 (1) ◽  
pp. 40-46
Author(s):  
Dmitri L. Khokhlov
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Standard Model ◽  
Active Galactic Nuclei ◽  
Planck Scale ◽  
Galactic Nuclei ◽  
High Energy ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
The Standard Model

AbstractThe studied conjecture is that ultra high energy cosmic rays (UHECRs) are hypothetical Planck neutrinos arising in the decay of the protons falling onto the gravastar. The proton is assumed to decay at the Planck scale into positron and four Planck neutrinos. The supermassive black holes inside active galactic nuclei, while interpreted as gravastars, are considered as UHECR sources. The scattering of the Planck neutrinos by the proton at the Planck scale is considered. The Planck neutrinos contribution to the CR events may explain the CR spectrum from 5 × 1018 eV to 1020 eV. The muon number in the Planck neutrinos-initiated shower is estimated to be larger by a factor of 3/2 in comparison with the standard model that is consistent with the observational data.

scholarly journals Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Upalaparna Banerjee ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman ◽  
Michael Spannowsky
Keyword(s):  
Standard Model ◽  
High Energy ◽  
Beyond The Standard Model ◽  
Minimal Extension ◽  
Effective Operator ◽  
Abelian Gauge ◽  
Gauge Symmetries ◽  
Higher Dimensional ◽  
The Standard Model ◽  
Mass Dimension

Abstract It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy experiments and on account of this, it must be included as an infrared (IR) degree of freedom (DOF) along with the SM ones. The rest of the non-SM particles are heavy enough to be directly experimentally inaccessible and can be integrated out. Now, to capture the effects of the complete theory, one must take into account the higher dimensional operators constituted of the SM DOFs and the minimal extension. This construction, BSMEFT, is in the same spirit as SMEFT but now with extra IR DOFs. Constructing a BSMEFT is in general the first step after establishing experimental evidence for a new particle. We have investigated three different scenarios where the SM is extended by additional (i) uncolored, (ii) colored particles, and (iii) abelian gauge symmetries. For each such scenario, we have included the most-anticipated and phenomenologically motivated models to demonstrate the concept of BSMEFT. In this paper, we have provided the full EFT Lagrangian for each such model up to mass dimension 6. We have also identified the CP, baryon (B), and lepton (L) number violating effective operators.

scholarly journals CALCULATING TWO- AND THREE-BODY DECAYS WITH FeynArts AND FormCalc

2003 ◽  
Vol 14 (09) ◽  
pp. 1273-1278 ◽  
Author(s):  
MICHAEL KLASEN
Keyword(s):  
Standard Model ◽  
Particle Production ◽  
High Energy Physics ◽  
High Energy ◽  
Energy Distributions ◽  
Particle Decay ◽  
The Standard Model ◽  
Decay Widths ◽  
Three Body ◽  
Energy Physics

The Feynman diagram generator FeynArts and the computer algebra program FormCalc allow for an automatic computation of 2→2 and 2→3 scattering processes in High Energy Physics. We have extended this package by four new kinematical routines and adapted one existing routine in order to accomodate also two- and three-body decays of massive particles. This makes it possible to compute automatically two- and three-body particle decay widths and decay energy distributions as well as resonant particle production within the Standard Model and the Minimal Supersymmetric Standard Model at the tree- and loop-level. The use of the program is illustrated with three standard examples: [Formula: see text], [Formula: see text], and [Formula: see text].

scholarly journals A CRITICAL LOOK AT PRECISION ELECTROWEAK DATA AT HIGH ENERGY—A HINT FOR PHYSICS BEYOND THE STANDARD MODEL?

1994 ◽  
Vol 09 (35) ◽  
pp. 3301-3312
Author(s):  
A. GURTU
Keyword(s):  
Standard Model ◽  
Pair Production ◽  
High Energy ◽  
Recent Measurement ◽  
Beyond The Standard Model ◽  
Full Data ◽  
Text Production ◽  
Basic Framework ◽  
The Standard Model ◽  
Precision Electroweak Data

High energy electroweak data, including the recent measurement of M top is analyzed within the basic framework of the standard model. While the experimentally measured value of [Formula: see text] implies a low value of M top , the rest of the data demands a much higher value. Estimates of M Higgs within the SM framework including and excluding this Rb measurement are given. Next this discrepancy is expressed in terms of a new parameter, [Formula: see text], the excess[Formula: see text] production compared to that expected from a SM fit. This parameter is determined to be (9.4 to 12.8) ± 5.0 MeV, implying an excess of over 10 000 [Formula: see text] events in each LEP experiment after the 1993 data is fully analyzed. The origin of these events could be non-minimal Higgs pair production which should be thoroughly searched for in the full data sample of ~2×106 events per LEP experiment. Unless this discrepancy eventually turns out to be a fluctuation one may be witnessing at LEP the advent of physics beyond the standard model.

scholarly journals W-boson production in the high energy electron-photon collisions

2019 ◽  
pp. 41-50
Author(s):  
Ivan A. Shershan ◽  
Tatiana V. Shishkina
Keyword(s):  
Standard Model ◽  
Cross Sections ◽  
W Boson ◽  
High Energy ◽  
New Physics ◽  
Coupling Constants ◽  
Boson Production ◽  
The Standard Model ◽  
Electron Photon ◽  
W Boson Production

In this paper the analysis of W-boson production process in high-energy electron-photon collisions as a tool to search for deviations from the Standard Model is considered. In particular, a set of extended gauge models, including anomalous multi-boson interactions, are discussed as a promising way for «new physics» study. A numerical analysis of the total cross sections of the processes was carried out. The lowest order radiative corrections in the soft-photon approximation within the Standard Model are taken into account. Calculations beyond the Standard Model was performed, the kinematic features of the cross sections were identified. The restrictions on the anomalous triple gauge boson coupling constants were analyzed and the kinematic areas to the search for their manifestations were obtained during the experiments at the International Linear Collider. The paper shows that the search for «new physics» effects based on electron-photon collisions around the W-boson production peak is the maximal promising. It was also shown that future experiments at high luminosity linear colliders will significantly clarify the constraints on anomalous gauge coupling constants.

scholarly journals A global view of the off-shell Higgs portal

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Maximilian Ruhdorfer ◽  
Ennio Salvioni ◽  
Andreas Weiler
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Vector Boson ◽  
Effective Interaction ◽  
Goldstone Boson ◽  
High Energy ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Higgs Portal ◽  
First Time

We study for the first time the collider reach on the derivative Higgs portal, the leading effective interaction that couples a pseudo Nambu-Goldstone boson (pNGB) scalar Dark Matter to the Standard Model. We focus on Dark Matter pair production through an off-shell Higgs boson, which is analyzed in the vector boson fusion channel. A variety of future high-energy lepton colliders as well as hadron colliders are considered, including CLIC, a muon collider, the High-Luminosity and High-Energy versions of the LHC, and FCC-hh. Implications on the parameter space of pNGB Dark Matter are discussed. In addition, we give improved and extended results for the collider reach on the marginal Higgs portal, under the assumption that the new scalars escape the detector, as motivated by a variety of beyond the Standard Model scenarios.

High(est) energy lepton colliders

2021 ◽  
pp. 2142016
Author(s):  
Roberto Franceschini
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
High Energy ◽  
New Physics ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Lepton Colliders ◽  
The Standard Model

We discuss the physics opportunities and challenges presented by high energy lepton colliders in the range of center-of-mass energy between few and several tens of TeV. The focus is on the progress attainable on the study of weak and Higgs interactions in connection with new physics scenarios motivated by the shortcomings of the Standard Model.

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