γγ→γZ SCATTERING AND ITS RELATED PROCESSES

2000 ◽  
Vol 15 (40) ◽  
pp. 2387-2400
Author(s):  
FANG-XIAO DONG ◽  
XIAN-JIAN ZHOU
Keyword(s):  
Standard Model ◽  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Charged Scalar ◽  
The Standard Model ◽  
Fermion Loop ◽  
Helicity Amplitudes

The analytic helicity amplitudes of Z→3γ, γγ→Zγ and γZ→γγ via W-loop and charged scalar-loop are presented. There is some difference between our results and those in Ref. 13 for Z→3γ via W-loop and fermion-loop, which has different physical meanings. We have calculated the unpolarized and polarized cross-sections for γγ→γZ process. We find that the total cross-section of γγ→γZ is larger than that of γγ→γγ at 500 GeV of γγ c.m.s. energy. In principle this process provides a test of the non-Abelian nature of the standard model.

scholarly journals H1jet, a fast program to compute transverse momentum distributions

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Alexander Lind ◽  
Andrea Banfi
Keyword(s):  
Transverse Momentum ◽  
Standard Model ◽  
Total Cross Section ◽  
Cross Section ◽  
New Physics ◽  
Leading Order ◽  
Current Version ◽  
Differential Distribution ◽  
The Standard Model ◽  
Momentum Distributions

AbstractWe present H1jet, a fast code that computes the total cross section and differential distribution in the transverse momentum of a colour singlet. In its current version, the program implements only leading-order $$2\rightarrow 1$$ 2 → 1 and $$2\rightarrow 2$$ 2 → 2 processes, but could be extended to higher orders. We discuss the processes implemented in H1jet, give detailed instructions on how to implement new processes, and perform comparisons to existing codes. This tool, mainly designed for theorists, can be fruitfully used to assess deviations of selected new physics models from the Standard Model behaviour, as well as to quickly obtain distributions of relevance for Standard Model phenomenology.

ASSOCIATED PRODUCTION OF LIGHT PSEUDOSCALAR BOSON η WITH TOP QUARK PAIRS IN THE SLH MODEL AT THE ILC

2011 ◽  
Vol 26 (21) ◽  
pp. 1577-1586 ◽  
Author(s):  
JINZHONG HAN ◽  
DAPENG YANG ◽  
XUELEI WANG
Keyword(s):  
Standard Model ◽  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Linear Collider ◽  
International Linear Collider ◽  
Quark Pairs ◽  
Associated Production ◽  
The Standard Model ◽  
The Cross

The light pseudoscalar boson η is the typical particle predicted by the Simplest Little Higgs (SLH) model. In this paper, we investigate some processes of the associated production of a light pseudoscalar boson η with a pair of top quarks in the SLH model at the International Linear Collider (ILC), i.e. [Formula: see text] and [Formula: see text]. We find that the cross-sections of these two processes could reach [Formula: see text] fb in the favorite parameter space in the SLH model, which is consistent with the results of the cross-section of [Formula: see text] in the standard model and the cross-section of [Formula: see text] in the minimal supersymmetric standard model. It should be clear that hundreds to thousands of η can be produced at the ILC per year, these processes of [Formula: see text] are really interesting in testing the standard model and searching the signs of the SLH model.

MIXING EFFECTS OF MIRROR LEPTONS IN e+e− → W+W− AT LEP II

1990 ◽  
Vol 05 (22) ◽  
pp. 1717-1729 ◽  
Author(s):  
SARDAR SINGH ◽  
A. K. NAGAWAT ◽  
N. K. SHARMA
Keyword(s):  
Standard Model ◽  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Differential Cross Sections ◽  
Mixing Effects ◽  
Model Predictions

The deviations from standard model predictions for the process e+e− → W+W− due to the inclusion of mixing between ordinary and mirror leptons are evaluated for (i) total cross section, (ii) forward-backward asymmetry and (iii) differential cross sections for the production of unpolarized/polarized W's at LEP II [Formula: see text] energy. For the presently known limits on mirror lepton mixings ( sin 2 ψ ≈ 0.02 to 0.06) and heavy mirror neutrinos (m N ≈ 100–300 GeV ), the relative deviations are large (∆ ≈ −2% to −20%). These could possibly allow discerning of mirror lepton mixing effects at LEP II.

scholarly journals Flavor-dependent radiative corrections in coherent elastic neutrino-nucleus scattering

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Oleksandr Tomalak ◽  
Pedro Machado ◽  
Vishvas Pandey ◽  
Ryan Plestid
Keyword(s):  
Standard Model ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Physics ◽  
Heavy Particle ◽  
New Physics ◽  
Effective Field ◽  
Radiative Corrections ◽  
The Standard Model ◽  
Nucleus Scattering

Abstract We calculate coherent elastic neutrino-nucleus scattering cross sections on spin-0 nuclei (e.g. 40Ar and 28Si) at energies below 100 MeV within the Standard Model and account for all effects of permille size. We provide a complete error budget including uncertainties at nuclear, nucleon, hadronic, and quark levels separately as well as perturbative error. Our calculation starts from the four-fermion effective field theory to explicitly separate heavy-particle mediated corrections (which are absorbed by Wilson coefficients) from light-particle contributions. Electrons and muons running in loops introduce a non- trivial dependence on the momentum transfer due to their relatively light masses. These same loops, and those mediated by tau leptons, break the flavor universality because of mass-dependent electromagnetic radiative corrections. Nuclear physics uncertainties significantly cancel in flavor asymmetries resulting in subpercent relative errors. We find that for low neutrino energies, the cross section can be predicted with a relative precision that is competitive with neutrino-electron scattering. We highlight potentially useful applications of such a precise cross section prediction ranging from precision tests of the Standard Model, to searches for new physics and to the monitoring of nuclear reactors.

TRIPLE GAUGE BOSON PRODUCTION IN e+e- COLLISIONS

1991 ◽  
Vol 06 (39) ◽  
pp. 3565-3572
Author(s):  
M. H. NOUS ◽  
M. El-KISHEN ◽  
A. M. ALGELANI
Keyword(s):  
Higgs Boson ◽  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Cross Section ◽  
Gauge Boson ◽  
Cross Sections ◽  
Production Cross ◽  
Boson Production ◽  
Production Mechanism ◽  
The Standard Model

The production cross-sections for a triple gauge boson has been investigated in both the standard model and the minimal supersymmetric standard model, via e+e-→W+W-Z0. All events that contain the Higgs-boson seem to have no influence in this process. At [Formula: see text], this process could be detected with a reasonable cross-section, the production mechanism in this case will be e+e-→Z0→W+W-→W+W-Z0.

scholarly journals PRELIMINARY MEASUREMENTS OF THE QUARK-ANTIQUARK PRODUCTION CROSS-SECTION IN E+E- ANNIHILATIONS UP TO LEP2 HIGHEST ENERGIES

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 342-344
Author(s):  
GIUSEPPE DELLA RICCA
Keyword(s):  
Standard Model ◽  
Pair Production ◽  
Cross Section ◽  
Cross Sections ◽  
Production Cross Section ◽  
Production Cross ◽  
Delphi Detector ◽  
The Standard Model ◽  
Model Predictions ◽  
The Cross

Data collected with the DELPHI detector at [Formula: see text] up to LEP2 highest energies (i.e. exceeding 205 GeV) have been used to extract preliminary values of the cross-sections for quark-antiquark pair-production in e + e - annihilations. The values found were used to test the Standard Model predictions and to seek for physics beyond it.

scholarly journals Differential cross-section measurements for the electroweak production of dijets in association with a Z boson in proton–proton collisions at ATLAS

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Standard Model ◽  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Azimuthal Angle ◽  
Proton Proton ◽  
Weak Boson ◽  
The Standard Model ◽  
Two Jets

AbstractDifferential cross-section measurements are presented for the electroweak production of two jets in association with a Z boson. These measurements are sensitive to the vector-boson fusion production mechanism and provide a fundamental test of the gauge structure of the Standard Model. The analysis is performed using proton–proton collision data collected by ATLAS at $$\sqrt{s}=13\ \hbox {TeV}$$ s = 13 TeV and with an integrated luminosity of $$139\ \hbox {fb}^{-1}$$ 139 fb - 1 . The differential cross-sections are measured in the $$Z\rightarrow \ell ^+\ell ^-$$ Z → ℓ + ℓ - decay channel ($$\ell =e,\mu $$ ℓ = e , μ ) as a function of four observables: the dijet invariant mass, the rapidity interval spanned by the two jets, the signed azimuthal angle between the two jets, and the transverse momentum of the dilepton pair. The data are corrected for the effects of detector inefficiency and resolution and are sufficiently precise to distinguish between different state-of-the-art theoretical predictions calculated using Powheg+Pythia8, Herwig7+Vbfnlo and Sherpa 2.2. The differential cross-sections are used to search for anomalous weak-boson self-interactions using a dimension-six effective field theory. The measurement of the signed azimuthal angle between the two jets is found to be particularly sensitive to the interference between the Standard Model and dimension-six scattering amplitudes and provides a direct test of charge-conjugation and parity invariance in the weak-boson self-interactions.

scholarly journals Measurement of the inclusive and differential t$$ \overline{t} $$γ cross sections in the single-lepton channel and EFT interpretation at $$ \sqrt{s} $$ = 13 TeV

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Standard Model ◽  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Center Of Mass ◽  
Effective Field ◽  
Data Set ◽  
The Standard Model ◽  
Direct Limits

Abstract The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The data set, corresponding to an integrated luminosity of 137 fb−1, was recorded by the CMS experiment during the 2016–2018 data taking of the LHC. The measurements are performed in a fiducial volume defined at the particle level. Events with an isolated, highly energetic lepton, at least three jets from the hadronization of quarks, among which at least one is b tagged, and one isolated photon are selected. The inclusive fiducial t$$ \overline{\mathrm{t}} $$ t ¯ γ cross section, for a photon with transverse momentum greater than 20 GeV and pseudorapidity |η| < 1.4442, is measured to be 798 ± 7(stat) ± 48(syst) fb, in good agreement with the prediction from the standard model at next-to-leading order in quantum chromodynamics. The differential cross sections are also measured as a function of several kinematic observables and interpreted in the framework of the standard model effective field theory (EFT), leading to the most stringent direct limits to date on anomalous electromagnetic dipole moment interactions of the top quark and the photon.

NOTE ON THE MEASUREMENT OF y-DEPENDENCE IN NEUTRINO-ELECTRON SCATTERING: A SENSITIVE TEST OF THE STANDARD MODEL

1993 ◽  
Vol 02 (04) ◽  
pp. 915-921 ◽  
Author(s):  
C. RANGACHARYULU ◽  
A. RICHTER
Keyword(s):  
Standard Model ◽  
Differential Cross Section ◽  
Cross Section ◽  
Electron Scattering ◽  
Differential Cross ◽  
Sensitive Test ◽  
Testing Ground ◽  
The Standard Model ◽  
Sensitive Testing

It is pointed out that the y-dependence of the differential cross-section for various types of neutrinos on the electron promises to be a sensitive testing ground of the electroweak Standard Model at KAON in Vancouver. Estimates of the flux requirements are given and the feasibility of such experiments is discussed.

TeV Scale B – L Phenomenology at LHC

2007 ◽  
Vol 22 (31) ◽  
pp. 5889-5908 ◽  
Author(s):  
M. Abbas ◽  
W. Emam ◽  
S. Khalil ◽  
M. Shalaby
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Cross Sections ◽  
Branching Ratios ◽  
Higgs Production ◽  
Neutrino Masses ◽  
Natural Explanation ◽  
The Standard Model ◽  
The Cross

We present the phenomenology of the low scale U(1)B–L extension of the standard model and its implications at LHC. We show that this model provides a natural explanation for the presence of three right-handed neutrinos and can naturally account the observed neutrino masses and mixing. We study the decay and production of the extra gauge boson and the SM singlet scalar (heavy Higgs) predicted in this type of models. We find that the cross sections of the SM-like Higgs production are reduced by ~ 20% – 30%, while its decay branching ratios remain intact. The extra Higgs has relatively small cross sections and the branching ratios of Z′ → l+l− are of order ~ 20% compared to ~ 3% of the SM results.

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