PRECISIQN DETERMINATIONS OF ELECTROWEAK PARAMETERS FROM ep—COLLISIONS AT HERA—ENERGIES

We have studied HERA's capability of precisely measuring various parameters of the electroweak standard model. The analysis was performed in kinematical regions, x≥0.01 and x≥0.1, where systematic errors are expected to be under control. The statistical precision reachable for standard model parameters, extracted from R≡σ NC /σCC and NC asymmetries A for polarized e± beams, was estimated for both regions. Heavy flavor contributions, which amount up to 15% to the cross sections, were included via the boson-gluon fusion process. Furthermore the influence of various uncertainties (parton distributions, quark masses, σL/σT fixing input parameters) was estimated. For x≥0.01 the uncertainties due to parton densities are sizeable, the total rates (cross sections), however, increase strongly in contrast to the region x≥0.1.

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PROBING THE ANOMALOUS COUPLINGS OF THE TOP QUARK WITH GLUON AT THE LHC AND TEVATRON

Modern Physics Letters A ◽

10.1142/s0217732313501708 ◽

2013 ◽

Vol 28 (37) ◽

pp. 1350170 ◽

Cited By ~ 7

Author(s):

HODA HESARI ◽

MOJTABA MOHAMMADI NAJAFABADI

Keyword(s):

Production Rate ◽

Cross Sections ◽

Top Quark ◽

Dipole Moments ◽

Gluon Fusion ◽

Fusion Process ◽

Small Range ◽

Anomalous Couplings ◽

Text Production ◽

Measured Ratio

In this paper, we study the sensitivity of the fraction of [Formula: see text] events arising from gluon–gluon fusion to the chromoelectric and chromomagnetic dipole moments (CEDM and CMDM) as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron. The sensitivity of measured charged asymmetry at the LHC to CEDM and CMDM is also studied. We find that at the Tevatron and the LHC, nonzero values of CMDM could suppress the [Formula: see text] production rate. It is shown that the ratio of [Formula: see text] at the Tevatron is more sensitive to CEDM and CMDM than the LHC case. The presence of CEDM always increases the contribution of gluon–gluon fusion process in top pair rate at the Tevatron and LHC. Except for a small range of CMDM, the presence of CEDM and CMDM can increase the fraction of gluon–gluon fusion at the Tevatron and LHC. The measured ratio of [Formula: see text] at the Tevatron is used to derive bounds on the chromoelectric and chromomagnetic dipole moments as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron, and the measured charged asymmetry at the LHC. The combination of [Formula: see text] and σ LHC provides stringent limits on CMDM and CEDM.

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Precision QCD measurements in DIS at HERA

Modern Physics Letters A ◽

10.1142/s0217732316300251 ◽

2016 ◽

Vol 31 (28) ◽

pp. 1630025

Author(s):

Daniel Britzger

Keyword(s):

Cross Sections ◽

Production Cross ◽

Distribution Functions ◽

Coupling Constants ◽

Charged Current ◽

Heavy Flavor ◽

Parton Distribution Functions ◽

Quark Masses ◽

Insight Into

New and recent results on QCD measurements from the H1 and ZEUS experiments at the HERA ep collider are reviewed. The final results on the combined deep-inelastic neutral and charged current cross-sections are presented and their role in the extractions of parton distribution functions (PDFs) is studied. The PDF fits give insight into the compatibility of QCD evolution and heavy flavor schemes with the data as a function of kinematic variables such as the scale Q2. Measurements of jet production cross-sections in ep collisions provide direct proves of QCD and extractions of the strong coupling constants are performed. Charm and beauty cross-section measurements are used for the determination of the heavy quark masses. Their role in PDF fits is investigated. In the regime of diffractive DIS and photoproduction, dijet and prompt photon production cross-sections provide insights into the process of factorization and the nature of the diffractive exchange.

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Heavy Quark Physics from Lattice NRQCD

International Journal of Modern Physics A ◽

10.1142/s0217751x97002164 ◽

1997 ◽

Vol 12 (22) ◽

pp. 4009-4018

Author(s):

John Sloan

Keyword(s):

Standard Model ◽

Heavy Quark ◽

Heavy Quark Physics ◽

Effective Action ◽

Systematic Errors ◽

Heavy Quarks ◽

Model Parameters ◽

Calculated Spectrum ◽

The Standard Model ◽

Lattice Calculations

I discuss recent lattice calculations of the spectroscopy of mesons containing only b and c quarks using the Non-Relativistic QCD (NRQCD) action for heavy quarks. I discuss the benefits of using a non-relativistic effective action in heavy quark calculations and the manner in which heavy quark systems are insensitive to the systematic errors common in lattice calculations. I discuss how these calculations can be used to determine the standard model parameters αs and mb by requiring that the calculated spectrum agree with experiment, and present our current estimates of these quantities.

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Top quark measurements in the CMS experiment

EPJ Web of Conferences ◽

10.1051/epjconf/201818202074 ◽

2018 ◽

Vol 182 ◽

pp. 02074

Author(s):

Luca Lista

Keyword(s):

Standard Model ◽

Cross Sections ◽

Top Quark ◽

Model Parameters ◽

Beyond The Standard Model ◽

Cms Experiment ◽

Single Top ◽

Theoretical Predictions ◽

Top Quark Production ◽

Quark Production

Experimental results on top-quark physics obtained at the CMS experiment are reported based on the data recorded at centre-of-mass energy up to 13 TeV. Inclusive and differential cross sections for both top-quark pair and single top-quark production are presented, as well as measurements of top-quark properties in production and decay, and searches for anomalous couplings. The presented measurements test theoretical predictions, including recent perturbative QCD calculations, provide constraints of fundamental standard model parameters, and set limits on physics beyond the standard model.

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Standard Model Physics from Quarkonia and Lattice QCD

International Journal of Modern Physics A ◽

10.1142/s0217751x97002188 ◽

1997 ◽

Vol 12 (22) ◽

pp. 4029-4038

Author(s):

James N. Simone

Keyword(s):

Standard Model ◽

Lattice Qcd ◽

Heavy Quark ◽

Lattice Spacing ◽

Systematic Errors ◽

Heavy Quarks ◽

Careful Attention ◽

Quark Masses

Quarkonia is studied in lattice QCD using Wilson heavy quarks improved to O(a) in the lattice spacing a. The quarkonia spectrum is compared to experiment and provides a check on lattice spacing errors. Careful attention to systematic errors in quarkonia permits determinations of the QCD coupling αs and the heavy quark masses.

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GLUON-FUSION-INDUCED Zg AND Zgg PRODUCTIONS IN THE STANDARD MODEL AT THE LHC

International Journal of Modern Physics A ◽

10.1142/s0217751x13501017 ◽

2013 ◽

Vol 28 (20) ◽

pp. 1350101

Author(s):

XIANGDONG GAO ◽

QIANG LI ◽

CAI-DIAN LÜ

Keyword(s):

Large Hadron Collider ◽

Standard Model ◽

Cross Sections ◽

Hadron Collider ◽

Gluon Fusion ◽

Leading Order ◽

Total Cross Sections ◽

The Standard Model

We report calculations of the gluon-induced Zg and Zgg productions in the Standard Model at the Large Hadron Collider (LHC) operating at both 7 TeV and 14 TeV collision energies. We present total cross-sections and differential distributions of the processes and compare them with the leading and next-to-leading order QCD pp → Z+1 jet, Z+2 jets results. Our results show that the gluon-induced Zg and Zgg productions contribute to pp → Z+1 jet, Z+2 jets at 1% level.

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Standard model measurements with ATLAS (+CMS) detector(s)

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194515601027 ◽

2015 ◽

Vol 39 ◽

pp. 1560102

Author(s):

Shu Li

Keyword(s):

Standard Model ◽

Cross Sections ◽

Center Of Mass ◽

Order Theory ◽

New Physics ◽

Effective Field ◽

Heavy Flavor ◽

Leading Order ◽

Center Of Mass Energy ◽

8 Tev

We present a broad range of Standard Model measurements performed in proton-proton collisions at the LHC on a variety of topics [Formula: see text]jets production and ratios, the electroweak multi-boson production, [Formula: see text] heavy flavor decay production, jet production, photon physics, the Standard Model soft QCD and diffractive physics. The latest public results from ATLAS experiment are obtained at the center-of-mass energy of both 7 TeV and 8 TeV, which covers total cross sections, fiducial cross sections, differential cross sections wherever available and comparison with Leading-Order/Next-to-Leading-Order/Next-to-Next-to-Leading-Order theory predictions. These measurements provide important tests for perturbative QCD, electroweak multi-boson interactions, Electroweak Symmetry Breaking over a broad kinematic range and constraints for PDFs. Model-independent new physics searches are also performed by probing anomalous gauge bosons couplings using effective Lagrangian or effective field theory formalism.

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Analyzing the Anomalous Dipole Moment Type Couplings of Heavy Quarks with FCNC Interactions at the CLIC

Advances in High Energy Physics ◽

10.1155/2014/717848 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

A. T. Tasci ◽

A. Senol ◽

C. Verep

Keyword(s):

Dipole Moment ◽

Standard Model ◽

Heavy Quark ◽

Cross Sections ◽

Linear Collider ◽

Heavy Quarks ◽

Decay Modes ◽

Quark Masses ◽

Single Production

We examine both anomalous magnetic and dipole moment type couplings of a heavy quark via its single production with subsequent dominant standard model decay modes at the compact linear collider (CLIC). The signal and background cross sections are analyzed for heavy quark masses 600 and 700 GeV. We make the analysis to delimitate these couplings as well as to find the attainable integrated luminosities for3σobservation limit.

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Charm and Beauty Production Cross-Section Measurements in Deep Inelastic Electron-Proton Scattering at HERA

Ukrainian Journal of Physics ◽

10.15407/ujpe64.7.543 ◽

2019 ◽

Vol 64 (7) ◽

pp. 543

Author(s):

V. Aushev

Keyword(s):

Cross Sections ◽

Production Cross ◽

Inelastic Electron ◽

Heavy Flavor ◽

Quark Masses ◽

Systematic Uncertainties ◽

Bjorken Scaling ◽

Qcd Analysis ◽

Scattering Cross Sections ◽

Beauty Production

The open charm and beauty production cross-sections in the deep inelastic ep scattering (DIS) at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross-sections are obtained in the kinematic range of negative four-momentum transfer squared of a photon 2.5≤ Q2 ≤2000 GeV2 and the Bjorken scaling variable 3×10¬5 ≤ xBj ≤5×10¬2. The different charm- and beauty-tagging methods are used for the heavy-flavor production study in DIS. The combined method accounts for the correlations of systematic uncertainties, as well as statistical uncertainties among the different datasets. Perturbative QCD (pQCD) calculations are compared to the measured combined data. A NLO QCD analysis is performed using these data together with the combined inclusive deep inelastic scattering cross-sections from HERA. The running charm- and beauty-quark masses are determined as mc(mc) = 1,290+0,046−0,041(exp /fit)+0,062−0,014(model)+0,03−0,031(parametrization) GeV and mb(mb) = 4,049+0,104−0,109(exp /fit)+0,090−0,032(model)+0,001−0,031(parametrization) GeV.

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