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

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.

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 348-350
Author(s):  
FABIO COSSUTTI

Data collected with the DELPHI detector at centre-of-mass energies up to the highest values explored by the LEP collider of about 206 GeV have been used to extract preliminary values of the cross-section for the process e+e- → W+W-. The branching ratios of the W decay were also measured; from them the value of |Vcs| was extracted. The results are compared with the most recent calculations in the framework of the Standard Model.


2020 ◽  
Vol 35 (25) ◽  
pp. 2050217
Author(s):  
Dang Van Soa ◽  
Bui Thi Ha Giang

An attempt is made to present the contribution of the scalar unparticle on some scattering processes in the Randall–Sundrum (RS) model. We have evaluated the contribution of the scalar unparticle on the W-pair production cross-sections at International Linear Colliders (ILC). The results indicate that at the low values of the scaling dimension and the bounds on scale [Formula: see text] are around few TeV, the cross-sections are much enhanced, which is quite comparable with the W-production in the Standard Model and hence it is worthwhile to explore in future colliders.


1986 ◽  
Vol 01 (08) ◽  
pp. 465-474 ◽  
Author(s):  
EMIDIO GABRIELLI

The calculations of production cross sections of W’ s and Z0’ s in e-p reactions at HERA energies and beyond are revised, improved and updated. Comparison with previous calculations show that in some cases the cross sections were considerably overestimated. The effects of a possible deviation of the W anomalous magnetic moment from the standard model value are also discussed.


2011 ◽  
Vol 26 (21) ◽  
pp. 1577-1586 ◽  
Author(s):  
JINZHONG HAN ◽  
DAPENG YANG ◽  
XUELEI WANG

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.


2007 ◽  
Vol 22 (38) ◽  
pp. 2873-2884
Author(s):  
DANIEL WHITESON

The dilepton decays of the top quark are a powerful laboratory for probing the Standard Model and searching for hints of a more fundamental theory. We present a detailed analysis of the production cross section and the kinematic qualities of top quark pair candidate events in [Formula: see text] collisions at [Formula: see text] = 1.96 TeV collected by the CDF detector which include two leptons in the final state, suggesting the decay [Formula: see text]. We describe the selection of candidate events to suppress major backgrounds and present the number of observed events over background. As a test of the top quark hypothesis, the kinematics of the events are analyzed via a measurement of M top with unprecedented precision.


2009 ◽  
Vol 18 (02) ◽  
pp. 302-308
Author(s):  
PENGNIAN SHEN ◽  
HANTAO JING ◽  
HUANQING CHIANG

The Λ-hypernucleus (LHN) production in the proton-induced reaction is studied in the distorted wave impulse approximation(DWIA). The cross sections for the LHN production in the reactions where the proton bombards the 6Li, 12C and 16O targets, respectively, are calculated. It is shown that the reaction cross sections are of the order of μb, and the distortion effects tend to reduce the cross sections by a factor of 3~10. For the sΛ–LHN production, the differential cross section is decreased with the increasing mass of the target nucleus. The pΛ–LHN production cross section is normally higher than that for the sΛ–LHN production. The double differential cross sections (DDXS) with respect to the momenta of the outgoing proton and kaon are also demonstrated. The missing mass spectra of the inclusive reaction p+A → p+K++X for the 6Li, 12C and 16O targets, an alternative way to study hypernuclear physics, are proposed. From these spectra, the masses of LHN can accurately be extracted. Moreover, the exotic LHN production in the same type of reaction is also studied . The same physical quantities are calculated. It is shown that the magnitude of the cross section is also in the order of μb. The halo effect of the core nucleus that locates at a place far away from the stable line would make the wave function broader, and consequently reduces the production cross section.


2001 ◽  
Vol 16 (supp01a) ◽  
pp. 336-338
Author(s):  
ANETTE BEHRMANN

A preliminary analysis of the lepton-pair production in e+e- annihilations at LEP2 center-of-mass energies using the data collected between 130 GeV and LEP2 highest energies (i.e. exceeding 205 GeV) with the DELPHI detector is presented. The values obtained for the cross-sections and forword-backward asymmetries are used to test the Standard Model predictions and to derive limits for possible new physics phenomena beyond it.


2014 ◽  
Vol 29 (11n12) ◽  
pp. 1450055 ◽  
Author(s):  
V. Arı ◽  
O. Çakır ◽  
S. Kuday

We study the pair production of new heavy leptons within a new U(1)′ symmetry extension of the Standard Model. Because of the new symmetry, the production and decay modes of the new heavy leptons would be different from those of three families of the standard model. The pair production cross-sections depending on the mixing parameter and the mass of heavy leptons have been calculated for the center-of-mass energies of 0.5 TeV, 1 TeV and 3 TeV. The accessible ranges of the parameters have been obtained for different luminosity projections at linear colliders. The search can be performed within the range of mixing parameter -1<x<-0.35 and 0.05<x<1, given that the heavy lepton mass Ml′ = 400 GeV at [Formula: see text] and L int = 100 fb -1. We find the sensitivity to the range of mixing parameter -1<x<1 for the mass range Ml′<800 GeV at [Formula: see text] and L int = 100 fb -1.


1991 ◽  
Vol 06 (39) ◽  
pp. 3565-3572
Author(s):  
M. H. NOUS ◽  
M. El-KISHEN ◽  
A. M. ALGELANI

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.


2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  

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.


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